Dr Gengfa Fang is the Funding Director of IoT Innovation Lab at UTS. He applies his expertise in Internet of Things (IoT) and machine learning technologies to the energy and healthcare industry by making them more predictable, manageable and intelligent to communities. His main research areas are IoT streaming data analytics and machine learning, localisation, 5G/6G communications and networking. His research has been funded by Cisco, SAS, Intel, NBN, and government research schemes including CRC-P and Innovation Connection.
Can supervise: YES
Chu, P, Zhang, JA, Wang, X, Fang, G & Wang, D 2020, 'Semi-Persistent Resource Allocation Based on Traffic Prediction for Vehicular Communications', IEEE Transactions on Intelligent Vehicles, vol. 5, no. 2, pp. 345-355.View/Download from: Publisher's site
Chu, P, Zhang, JA, Wang, X, Fei, Z, Fang, G & Wang, D 2020, 'Interference Characterization and Power Optimization for Automotive Radar With Directional Antenna', IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY, vol. 69, no. 4, pp. 3703-3716.View/Download from: Publisher's site
Song, X, Fan, X, Xiang, C, Ye, Q, Liu, L, Wang, Z, He, X, Yang, N & Fang, G 2019, 'A Novel Convolutional Neural Network Based Indoor Localization Framework With WiFi Fingerprinting', IEEE Access, vol. 7, pp. 110698-110709.View/Download from: Publisher's site
With the ubiquitous deployment of wireless systems and pervasive availability of smart devices, indoor localization is empowering numerous location-based services. With the established radio maps, WiFi fingerprinting has become one of the most practical approaches to localize mobile users. However, most fingerprint-based localization algorithms are computation-intensive, with heavy dependence on both offline training phase and online localization phase. In this paper, we propose CNNLoc, a Convolutional Neural Network (CNN) based indoor localization system with WiFi fingerprints for multi-building and multi-floor localization. Specifically, we devise a novel classification model and a novel positioning model by combining a Stacked Auto-Encoder (SAE) with a one-dimensional CNN. The SAE is utilized to precisely extract key features from sparse Received Signal Strength (RSS) data while the CNN is trained to effectively achieve high accuracy in the positioning phase. We evaluate the proposed system on the UJIIndoorLoc dataset and Tampere dataset and compare the performance with several state-of-the-art methods. Moreover, we further propose a newly collected WiFi fingerprinting dataset UTSIndoorLoc and test the positioning model of CNNLoc on it. The results show CNNLoc outperforms the existing solutions with 100% and 95% success rates on building-level localization and floor-level localization, respectively.
Zheng, G, Yang, W, Valli, C, Shankaran, R, Abbas, H, Zhang, G, Fang, G, Chaudhry, J & Qiao, L 2019, 'Fingerprint Access Control for Wireless Insulin Pump Systems Using Cancelable Delaunay Triangulations', IEEE Access, vol. 7, pp. 75629-75641.View/Download from: Publisher's site
© 2013 IEEE. An insulin pump is a small wearable medical gadget which can mimic the way a healthy pancreas functions by providing continuous subcutaneous insulin infusion for the patient. However, in the current products, the access to the pump is not securely controlled, rendering the pump insecure to harmful or even lethal attacks, such as those that lead to the privacy breach of the patient and the delivery of abnormal dosage of insulin to the patient. In a conventional symmetric key-based security solution, how to distribute and manage the key is quite challenging, since the patient bearing an insulin pump may visit any hospital or clinic to receive treatment from any qualified doctor. In order to prevent malicious access to the pump, in this paper, we propose a Fingerprint-based Insulin Pump security (FIPsec) scheme which requires an entity to first pass the fingerprint authentication process before it is allowed to access the insulin pump. With this scheme, the request from an adversary to access the pump will be blocked thereby protecting the pump from the possibility of being subjected to serious attacks during the post-request period. In the scheme, a cancelable Delaunay triangle-based fingerprint matching algorithm is proposed for the insulin pump, which has capabilities to resist against nonlinear fingerprint image distortion and the influence of missing or spurious minutiae. In order to evaluate the performance of the proposed fingerprint matching algorithm, we perform comprehensive experiments on FVC2002 DB1 and DB2 fingerprint databases. The results show that the FIPsec scheme can achieve a reasonably low equal error rate and thus becomes a viable solution to thwarting unauthorized access to the insulin pump.
Fan, X, He, X, Xiang, C, Puthal, D, Gong, L, Nanda, P & Fang, G 2018, 'Towards System Implementation and Data Analysis for Crowdsensing BasedOutdoor RSS Maps', IEEE Access, vol. 6.View/Download from: Publisher's site
With the explosive usage of smart mobile devices, sustainable access to wireless networks (e.g., WiFi) has become a pervasive demand. Most mobile users expect seamless network connection with low cost. Indeed,
this can be achieved by using an accurate received signal strength (RSS) map of wireless access points. While existing methods are either costly or unscalable, the recently emerged mobile crowdsensing (MCS)
paradigm is a promising technique for building RSS maps. MCS applications leverage pervasive mobile devices to collaboratively collect data. However, the heterogeneity of devices and the mobility of users
could cause inherent noises and blank spots in collected dataset. In this paper, we study (1) how to tame the sensing noises from heterogenous mobile devices, and (2) how to construct accurate and complete RSS
maps with random mobility of crowdsensing participants. First, we build a mobile crowdsensing system called iMap to collect RSS measurements with heterogeneous mobile devices. Second, through observing
experimental results, we build statistical models of sensing noises and derive different parameters for each kind of mobile device. Third, we present the signal transmission model with measurement error model, and we propose a novel signal recovery scheme to construct accurate and complete RSS maps. The evaluation results show that the proposed method can achieve 90% and 95% recovery rate in geographic coordinate
system and polar coordinate system, respectively.
Li, X, Shankaran, R, Orgun, MA, Fang, G & Xu, Y 2018, 'Resource Allocation for Underlay D2D Communication with Proportional Fairness', IEEE Transactions on Vehicular Technology, vol. 67, no. 7, pp. 6244-6258.View/Download from: Publisher's site
© 1967-2012 IEEE. As an emerging paradigm, device-to-device (D2D) communication has the capability to complement and enhance the conventional cellular network by offering high spectral and energy efficiency. However, the problem of cochannel interference makes the resource allocation very complex and challenging in underlay D2D communication networks. This paper proposes a novel joint power control and resource scheduling scheme to enhance both the network throughput and the users' fairness of the underlay D2D communication networks. Unlike other previous work in this area, our scheme aims at maximizing the sum of all users' proportional fairness functions, while simultaneously taking into account factors such as fairness, signal-to-interference-plus-noise ratio requirements, and severe interference. The proposed scheme offers a practical solution because it works for lengthy time slots, a realistic scenario for the underlay D2D communication system. We also take into consideration the time-varying feature of user's channel condition in our proposed solution. Numerical results confirm that our proposed scheme not only dramatically improves the system throughput, but also boosts the system fairness while guaranteeing the Quality-of-Service levels of all D2D users and cellular users.
Zhang, X, Lin, J, Chen, Z, Sun, F, Zhu, X & Fang, G 2018, 'An Efficient Neural-Network-Based Microseismic Monitoring Platform for Hydraulic Fracture on an Edge Computing Architecture.', Sensors (Basel, Switzerland), vol. 18, no. 6.View/Download from: Publisher's site
Microseismic monitoring is one of the most critical technologies for hydraulic fracturing in oil and gas production. To detect events in an accurate and efficient way, there are two major challenges. One challenge is how to achieve high accuracy due to a poor signal-to-noise ratio (SNR). The other one is concerned with real-time data transmission. Taking these challenges into consideration, an edge-computing-based platform, namely Edge-to-Center LearnReduce, is presented in this work. The platform consists of a data center with many edge components. At the data center, a neural network model combined with convolutional neural network (CNN) and long short-term memory (LSTM) is designed and this model is trained by using previously obtained data. Once the model is fully trained, it is sent to edge components for events detection and data reduction. At each edge component, a probabilistic inference is added to the neural network model to improve its accuracy. Finally, the reduced data is delivered to the data center. Based on experiment results, a high detection accuracy (over 96%) with less transmitted data (about 90%) was achieved by using the proposed approach on a microseismic monitoring system. These results show that the platform can simultaneously improve the accuracy and efficiency of microseismic monitoring.
Sun, B, Guo, Y, Fang, G & Dutkiewicz, E 2017, 'An efficient dictionary refinement algorithm for multiple target counting and localization in wireless sensor networks', International Journal of Distributed Sensor Networks, vol. 13, no. 8.View/Download from: Publisher's site
© The Author(s) 2017. Many applications provided by wireless sensor networks rely heavily on the location information of the monitored targets. Since the number of targets in the region of interest is limited, localization benefits from compressive sensing, sampling number can be greatly reduced. Despite many compressive sensing–based localization methods proposed, existing solutions are based on the assumption that all targets fall on a sampled and fixed grid, performing poorly when there are targets deviating from the grid. To address such a problem, in this article, we propose a dictionary refinement algorithm where the grid is iteratively adjusted to alleviate the deviation. In each iteration, the representation coefficient and the grid parameters are updated in turn. After several iterations, the measurements can be sparsely represented by the representation coefficient which indicates the number and locations of multiple targets. Extensive simulation results show that the proposed dictionary refinement algorithm achieves more accurate counting and localization compared to the state-of-the-art compressive sensing reconstruction algorithms.
Wang, H, Nguyen, D, Dutkiewicz, Fang & Mueck 2017, 'Negotiable Auction based on Mixed Graph: A Novel Spectrum Sharing Framework', IEEE Transactions on Cognitive Communications and Networking, vol. 3, no. 3, pp. 390-403.View/Download from: Publisher's site
Auction-based spectrum sharing is a promising solution to improve the spectrum utilization in 5G networks. Along with the spatial reuse, we observe that the ability to adjust the coverage of a spectrum bidder can provide room to itself for further negotiation while auctioning. In this paper, we propose a novel economic tool, size-negotiable auction mechanism (SNAM), which provides a hybrid solution between auction and negotiation for multi-buyers sharing spectrum chunks from a common database. Unlike existing auction-based spectrum sharing models, each bidder of the SNAM submits its bid for using the spectrum per unit space and a set of coverage ranges over which the bidder is willing to pay for the spectrum. The auctioneer then coordinates the interference areas (or coverage negotiation) to ensure no two winners interfere with each other while aiming to maximize the auction's total coverage area or revenue. In this scenario, the undirected graph used by existing auction mechanisms fails to model the interference among bidders. Instead, we construct a mixed interference graph and prove that SNAM's auctioning on the mixed graph is truthful and individually rational. Simulation results show that, compared with existing auction approaches, the proposed SNAM dramatically improves the spatial efficiency, hence leads to significantly higher seller revenue and buyer satisfaction under various setups. Thanks to its low complexity and low overhead, SNAM can target fine timescale trading (in minutes or hours) with a large number of bidders and requested coverages.
Zheng, G, Fang, G, Shankaran, R, Orgun, MA, Zhou, J, Qiao, L & Saleem, K 2017, 'Multiple ECG Fiducial Points-Based Random Binary Sequence Generation for Securing Wireless Body Area Networks.', IEEE Journal of Biomedical and Health Informatics, vol. 21, no. 3, pp. 655-663.View/Download from: Publisher's site
Generating random binary sequences (BSes) is a fundamental requirement in cryptography. A BS is a sequence of N bits, and each bit has a value of 0 or 1. For securing sensors within wireless body area networks (WBANs), electrocardiogram (ECG)-based BS generation methods have been widely investigated in which interpulse intervals (IPIs) from each heartbeat cycle are processed to produce BSes. Using these IPI-based methods to generate a 128-bit BS in real time normally takes around half a minute. In order to improve the time efficiency of such methods, this paper presents an ECG multiple fiducial-points based binary sequence generation (MFBSG) algorithm. The technique of discrete wavelet transforms is employed to detect arrival time of these fiducial points, such as P, Q, R, S, and T peaks. Time intervals between them, including RR, RQ, RS, RP, and RT intervals, are then calculated based on this arrival time, and are used as ECG features to generate random BSes with low latency. According to our analysis on real ECG data, these ECG feature values exhibit the property of randomness and, thus, can be utilized to generate random BSes. Compared with the schemes that solely rely on IPIs to generate BSes, this MFBSG algorithm uses five feature values from one heart beat cycle, and can be up to five times faster than the solely IPI-based methods. So, it achieves a design goal of low latency. According to our analysis, the complexity of the algorithm is comparable to that of fast Fourier transforms. These randomly generated ECG BSes can be used as security keys for encryption or authentication in a WBAN system.
Fang, G, Orgun, MA, Shankaran, R, Dutkiewicz, E & Zheng, G 2016, 'Truthful Channel Sharing for Self Coexistence of Overlapping Medical Body Area Networks.', PLoS ONE, vol. 11, no. 2, pp. 1-19.View/Download from: Publisher's site
As defined by IEEE 802.15.6 standard, channel sharing is a potential method to coordinate inter-network interference among Medical Body Area Networks (MBANs) that are close to one another. However, channel sharing opens up new vulnerabilities as selfish MBANs may manipulate their online channel requests to gain unfair advantage over others. In this paper, we address this issue by proposing a truthful online channel sharing algorithm and a companion protocol that allocates channel efficiently and truthfully by punishing MBANs for misreporting their channel request parameters such as time, duration and bid for the channel. We first present an online channel sharing scheme for unit-length channel requests and prove that it is truthful. We then generalize our model to settings with variable-length channel requests, where we propose a critical value based channel pricing and preemption scheme. A bid adjustment procedure prevents unbeneficial preemption by artificially raising the ongoing winner's bid controlled by a penalty factor λ. Our scheme can efficiently detect selfish behaviors by monitoring a trust parameter α of each MBAN and punish MBANs from cheating by suspending their requests. Our extensive simulation results show our scheme can achieve a total profit that is more than 85% of the offline optimum method in the typical MBAN settings.
Lei, C, Bie, H, Fang, G, Gaura, E, Brusey, J, Zhang, X & Dutkiewicz, E 2016, 'A Low Collision and High Throughput Data Collection Mechanism for Large-Scale Super Dense Wireless Sensor Networks', SENSORS, vol. 16, no. 7.View/Download from: Publisher's site
Shrestha, S, Fang, G, Dutkiewicz, E & Huang, X 2016, 'Solving hidden terminal problem in MU-MIMO WLANs with fairness and throughput-aware precoding and a degrees-of-freedom-based MAC design', EURASIP JOURNAL ON WIRELESS COMMUNICATIONS AND NETWORKING.View/Download from: Publisher's site
Tong, X, Fang, G, Nguyen, DN, Lin, J & Cabrera, E 2016, 'An Energy-Balanced Routing Algorithm in Wireless Seismic Sensor Network', Journal of Computational and Theoretical Nanoscience, vol. 13, no. 10, pp. 6823-6833.View/Download from: Publisher's site
Due to unpredictable geological outdoor environments and imbalances in energy consumption of seismometer nodes in the wireless seismic sensor networks (WSSN), some seismometer nodes fail much earlier than others due to power loss. This would cause hot spot problems, network partitions, and significantly shorten network lifetime. In this paper, we designed an energy-balanced routing algorithm (EBRA) to ensure balanced energy consumption from all seismometer nodes in the WSSN and to enhance the connectivity and lifetime of the WSSN. By aiming at minimizing the imbalance in the residual energy, we divide the routing algorithm into two parts: clustering formation and inter-cluster routing. In clustering formation, we design an energy-balanced clustering algorithm, which selects the cluster head dynamically, based on residual energy, distance between the seismometer node and data collector. The clustering algorithm mitigates hot spot problems by balancing energy consumption among seismometer nodes. In regards to inter-cluster routing, we can relate it to the pareto-candidate set. To reduce the average multi-hop delay from cluster heads to the data collector, we optimize the pareto-candidate set by Hamming distance. In the design of EBRA, we consider minute details such as energy consumed by transmitting bits and impact of average multi-hop delay. This adds to the novelty of this work compared to the existing studies. Simulation results demonstrated a reduction in the average multi-hop delay by 87.5% with network size of 200 nodes in ten different data collector locations. Our algorithm also improves the network lifetime over the others three schemes by 7.8%, 23% and 45.4%, respectively.
Lei, C, Bie, H, Fang, G, Mueck, M & Zhang, X 2016, 'An Efficient Backoff Algorithm Based on the Theory of Confidence Interval Estimation', IEICE TRANSACTIONS ON COMMUNICATIONS, vol. E99B, no. 10, pp. 2179-2186.View/Download from: Publisher's site
Tong, X, Fang, G & Lin, J 2016, 'A novel approach of energy efficiency based on multiple data collector placement for wireless seismic sensor network', Journal of Computational and Theoretical Nanoscience, vol. 13, no. 10, pp. 6834-6843.View/Download from: Publisher's site
© Copyright 2016 American Scientific Publishers All rights reserved. Since the geological environments are highly unpredictable and the battery capacity of seismometer nodes in the wireless seismic sensor networks (WSSN) is constraint, the lifetime of the network that using conventional single data collector may be dramatically reduced. Even with the most energyefficient algorithm that deploys multiple data collectors, it is still too difficult to satisfy the system requirement in terms of energy consumption. In this paper, we therefore propose an optimal solution that uses multiple data collectors to minimize the total energy consumption of data transmissions in WSSN. The aim of this work is not only to determine how many data collectors are required, but also to find out how to place them in an effective way, so that the energy efficiency of the system can be further enhanced. In so doing, an optimal solution that is based on the placement of multiple data collectors is proposed. A two-step approach is adopted, in which the number of required data collectors is firstly calculated based on a graph theoretic approach and then the placement of the data collectors are further optimized according to maximize the network lifetime. The simulation analysis shows that with a given number of seismometer nodes, using the proposed algorithm, an optimal value can always be found to extend the WSSN lifetime. As the number of seismometer nodes are selected to be 200, 500, 800 and 1000, the lifetime of the WSSN can be improved by 176%, 236.8%, 408.4% and 575%, respectively.
Zhou, J, Dutkiewicz, E, Liu, RP, Fang, G & Liu, Y 2015, 'Energy efficient duty cycle design based on quantum immune clonal evolutionary algorithm in body area networks', EAI Endorsed Transactions on Energy Web, vol. 16, no. 9.View/Download from: Publisher's site
Duty cycle design is an important topic in body area networks. As small sensors are equipped with the limited power source, the extension of network lifetime is generally achieved by reducing the network energy consumption, for instance through duty cycle schemes. However, the duty cycle design is a highly complex NP-hard problem and its computational complexity is too high with exhaustive search algorithm for practical implementation. In order to extend the network lifetime, we proposed a novel quantum immune clonal evolutionary algorithm (QICEA) for duty cycle design while maintaining full coverage in the monitoring area. The QICEA is tested, and a performance comparison is made with simulated annealing (SA) and genetic algorithm (GA). Simulation results show that compared to the SA and the GA, the proposed QICEA can extending the lifetime of body area networks and enhancing the energy efficiency effectively.
Zhou, J, Dutkiewicz, E, Liu, RP, Fang, G & Liu, Y 2015, 'Low energy clustering in BAN based on fuzzy simulated evolutionary computation', EAI Endorsed Transactions on Energy Web, vol. 16, no. 8, pp. 1-7.View/Download from: Publisher's site
© 2015 ICST.A low energy clustering method of body area networks based on fuzzy simulated evolutionary computation is proposed in this paper. To reduce communication energy consumption, we also designed a fuzzy controller to dynamically adjust the crossover and mutation probability. Simulations are conducted by using the proposed method, the clustering methods based on the particle swarm optimization and the method based on the quantum evolutionary algorithm. Results show that the energy consumption of the proposed method decreased compared with the other two methods, which means that the proposed method significantly improves the energy efficiency.
Zhou, J, Dutkiewicz, E, Liu, RP, Huang, X, Fang, G & Liu, Y 2015, 'A Modified Shuffled Frog Leaping Algorithm for PAPR Reduction in OFDM Systems', IEEE TRANSACTIONS ON BROADCASTING, vol. 61, no. 4, pp. 698-709.View/Download from: Publisher's site
Lei, C, Bie, H, Fang, G & Zhang, X 2015, 'An adaptive channel access method for dynamic super dense wireless sensor networks', Sensors (Switzerland), vol. 15, no. 12, pp. 30221-30239.View/Download from: Publisher's site
© 2015 by the authors; licensee MDPI, Basel, Switzerland. Super dense and distributed wireless sensor networks have become very popular with the development of small cell technology, Internet of Things (IoT), Machine-to-Machine (M2M) communications, Vehicular-to-Vehicular (V2V) communications and public safety networks. While densely deployed wireless networks provide one of the most important and sustainable solutions to improve the accuracy of sensing and spectral efficiency, a new channel access scheme needs to be designed to solve the channel congestion problem introduced by the high dynamics of competing nodes accessing the channel simultaneously. In this paper, we firstly analyzed the channel contention problem using a novel normalized channel contention analysis model which provides information on how to tune the contention window according to the state of channel contention. We then proposed an adaptive channel contention window tuning algorithm in which the contention window tuning rate is set dynamically based on the estimated channel contention level. Simulation results show that our proposed adaptive channel access algorithm based on fast contention window tuning can achieve more than 95% of the theoretical optimal throughput and 0.97 of fairness index especially in dynamic and dense networks.
© 2015 IEEE. We present an electroc1ardiogram (ECG)-based data encryption (EDE) scheme for implantable medical devices (IMDs). IMDs, including pacemakers and cardiac defibrillators, perform therapeutic or even life-saving functions and store sensitive data; therefore, it is important to prevent adversaries from having access to them. The EDE is designed with the ability to provide information-theoretically unbreakable encryption where two well-known techniques of classic one-time pads (OTPs) and error correcting codes are combined to achieve a cryptographic primitive for IMDs. Unlike other ECG-based key agreement schemes where ECG features are used to facilitate a key distribution, in the EDE scheme, random binary strings generated from ECG signals are directly used as keys for encryption. OTP keys are generated by the IMD and the programmer, respectively, before each encryption attempt; thus, the EDE does not require a cryptographic infrastructure to support a key distribution, storage, revocation, and refreshment. Protected by the EDE, IMDs could not be accessed by adversaries; however, medical personnel can have access to them by measuring real-time ECG data in emergencies. Therefore, the EDE design achieves a balance of high security and high accessibility for the IMD. Our data and security analysis shows that the EDE is a viable scheme for protecting IMDs.
Sun, Y, Zhang, YC, Feng, B, Fang, GF, Shi, JL & Dutkiewicz, E 2008, 'Research of extensions to RSVP for mobile IPv6 networks', Ruan Jian Xue Bao/Journal of Software, vol. 19, no. 7, pp. 1731-1742.View/Download from: Publisher's site
Aiming at the features of wireless mobile communication, this paper proposes a new resource reservation scheme, Fast RSVP, to guarantee the QoS of sessions for Mobile IPv6. The scheme adopts cross-layer design, it cooperates two modules at different layers: mobile IP module and RSVP module. By adding some primitives, the scheme let the two modules work together to guarantee the QoS of sessions for mobile users. Fast RSVP imports a series of new mechanisms such as advanced resource reservation on neighbor tunnels, resource reservation on optimized routes, resource reservation for handover sessions, path merge etc. Simulation results show that Fast RSVP scheme, compared with other traditional RSVP extensions for mobile environments, has the following advantages: (1) it realizes a mobile node handover with QoS guarantees; (2) it avoids resource wasting caused by triangular routes and duplicate reservations in Mobile IP handover process; (3) it distinguishes different types of reservation requests, greatly reducing the handover session forced termination rate while maintaining high performance of the network.
Tian, L, Yang, YB, Fang, GF, Shi, JL & Eryk, D 2008, 'A scheduling set based integrated scheduling algorithm for unicast and multicast traffic', Ruan Jian Xue Bao/Journal of Software, vol. 19, no. 12, pp. 3196-3206.View/Download from: Publisher's site
A new problem is addressed, which is how to improve energy efficiency for both unicast and multicast services without violating QoS requirements of mobile stations in 802.16e wireless networks. To solve this problem, a scheduling set based integrated scheduling (SSBIS) algorithm is proposed. SSBIS partitions all the mobile stations into multicast scheduling sets and a unicast scheduling set. All the unicast data of the mobile stations in the multicast scheduling sets are transmitted in the adjacent intervals of their multicast data transmission periods, and for the mobile stations in the unicast scheduling set, longest sleep duration based (LSDB) scheduling scheme is obtained using convex optimization to improve energy efficiency of the whole system. Numerical results show that SSBIS can save overall energy significantly and guarantee the minimum data rates of mobile stations at the same time. © 2008 by Journal of Software.
Sun, Y, Fang, G & Shi, J 2006, 'Research on the implementation of VoIP service in mobile Ad Hoc network', Jisuanji Gongcheng/Computer Engineering, vol. 32, no. 18, pp. 99-101.
This paper presents a new way to design VoIP application on mobile Ad Hoc network, which can correctly solve the problem of variable IP addresses in MANET and allows the nodes to communicate with each other reliably.
Ye, Q, Fan, X, Fang, G, Bie, H, Song, X & Shankaran, R 2020, 'CapsLoc: A Robust Indoor Localization System with WiFi Fingerprinting Using Capsule Networks', IEEE International Conference on Communications.View/Download from: Publisher's site
© 2020 IEEE. With the unprecedented demand of location-based services in indoor scenarios, wireless indoor localization is emerging as an essential application for mobile users. While the line-of-sight GPS signal is not available at indoor spaces, WiFi fingerprinting using received signal strength (RSS) has become popular with its ubiquitous accessibility. Although the fingerprinting data can be easily collected by portable mobile devices, to achieve robust and efficient indoor localization remains challenging with two constraints. First, the localization accuracy will be degraded by the random fluctuation of signals that caused by multipath effects from RSS signals. Second, indoor localization algorithms are time-consuming due to the handcrafting features and complex filtering on raw dataset. To achieve high localization accuracy with WiFi fingerprinting, in this paper, we propose CapsLoc, a robust indoor localization system by using capsule networks. Specifically, the capsule network model can efficiently extract hierarchical structures from WiFi fingerprint with three main components, including a convolutional layer, a primary capsule layer and a feature capsule layer. We conduct a real-world experimental field test with over 33600 data points. The experimental results show that CapsLoc can achieve accurate indoor localization with an averaged error of 0.68 m, which outperforms conventional machine learning methods (KNN and SVM) and existing deep learning methods (CNN and SAE-CNN).
Yuan, Y, Kong, X, Fang, G, Liu, L & Khruahong, S 2019, 'Development of Semantic Model of Multi-Level-Building Navigation Using Indoor Ontology and Dijkstra's Algorithm', 2019 20th International Conference on Parallel and Distributed Computing, Applications and Technologies (PDCAT), International Conference on Parallel and Distributed Computing, Applications and Technologies, IEEE, Gold Coast, Australia.View/Download from: Publisher's site
Location based services (LBS) can be separated
into a number of layers: technology layer, application layer,
standard layer, and social-ethical layer. This paper presents an
ontology development at standard layer. We developed an
ontology to identify and classify indoor semantic information to
guide the development of LBS applications for multi-level
building navigation. This ontology proposed models of multilevel
building properties as classes of building, level, zone, link,
node, and coordinate. To apply this ontology, we develop an
indoor navigation algorithm using the ontology classes and
Dijkstra's algorithm for shortest path in user navigation. A
prototype and experiments are implemented to validate this
Chu, P, Zhang, JA, Wang, X, Fang, G & Wang, D 2019, 'Semi-persistent v2x resource allocation with traffic prediction in two-tier cellular networks', IEEE Vehicular Technology Conference, IEEE Vehicular Technology Conference, IEEE, Kuala Lumpur, Malaysia.View/Download from: Publisher's site
© 2019 IEEE. In a dense urban area, conventional cellular V2X communications require frequent and heavy resource allocation, which can lead to processing congestion and large delay. In this paper, we propose a semi- persistent resource allocation scheme using the least minimum mean square error (LMMSE) traffic prediction in a two-tier network. The two-tier network architecture includes a central macro base station (MBS) and multiple roadside units (RSU). In the proposed scheme, the MBS pre-allocates persistent resource to RSUs based on predicted traffic, and then allocate dynamic resource upon real-time requests from vehicles through RSUs. We formulate an optimization problem for minimizing the total bandwidth under latency constraints and provide an optimal solution to the problem. Simulation is conducted for both artificially generated and real-world data, and the results validate the effectiveness of the proposed semi- persistent scheme.
Islam, MR, Lu, H, Fang, G, Li, L & Hossain, MJ 2019, 'Optimal Dispatch of Electrical Vehicle and PV Power to Improve the Power Quality of an Unbalanced Distribution Grid', 2019 Proceedings of International Conference on High Performance Big Data and Intelligent Systems (HPBD&IS), 2019 International Conference on High Performance Big Data and Intelligent Systems (HPBD&IS), IEEE, Shenzhen, China.View/Download from: Publisher's site
Kong, X, Fang, G, Liu, L & Tran, T 2019, 'Low Computational Data Fusion Approach Using INS and UWB for UAV Navigation Tasks in GPS Denied Environments', 2019 20th International Conference on Parallel and Distributed Computing, Applications and Technologies (PDCAT), International Conference on Parallel and Distributed Computing, Applications and Technologies, IEEE, Gold Coast, Australia.View/Download from: Publisher's site
This paper presents a low computational approach for unmanned aerial vehicles (UAV) navigation in GPS-denied environments. This approach is aiming to reduce computation load for UAV flying mission constraints. Small size, light weight on board hardware are constraints for UAV deployment and flying missions. The on board processor should not be built with high complexity and should consume as little computing as possible. Most existing approaches use Kalman filter, extended Kalman filter, Unscented filter, or particle filter to fuse different types of onboard sensor data to estimate UAV position. We developed a data fusion architecture that does not use these filters. We use an ultra-light-coupling fusion architecture. In this architecture, primary sensor and secondary sensor data are fused. When the secondary sensor is unavailable in most of the time, the UAV navigation uses the output of the primary sensor. When the secondary sensor signal is available, the primary sensor is re-aligned using the secondary sensor signal to bond the errors. In our approach, the primary sensor is Inertial Measurement Unit (IMU), and the secondary sensor inputs are from Ultra-wideband system (UWB). This approach is validated using demonstration of comparison of computing load, and simulation results for accuracy and reliability testing using UAV flying mission scenario.
Shi, Z, Zhang, JA, Xu, Y & Fang, G 2018, 'Human Activity Recognition Using Deep Learning Networks with Enhanced Channel State information', 2018 IEEE Globecom Workshops (GC Wkshps), IEEE Globecom Workshops, IEEE, Abu Dhabi, United Arab Emirates.View/Download from: Publisher's site
Channel State Information (CSI) is widely used for device free human activity recognition. Feature extraction remains as one of the most challenging tasks in a dynamic and complex environment. In this paper, we propose a human activity recognition scheme using Deep Learning Networks with enhanced Channel State information (DLN-eCSI). We develop a CSI feature enhancement scheme (CFES), including two modules of background reduction and correlation feature enhancement, for preprocessing the data input to the DLN. After cleaning and compressing the signals using CFES, we apply the recurrent neural networking (RNN) to automatically extract deeper features and then the softmax regression algorithm for activity classification. Extensive experiments are conducted to validate the effectiveness of the proposed scheme.
Song, X, Fan, X, He, X, Xiang, C, Ye, Q, Huang, X, Fang, G, Chen, LL, Qin, J & Wang, Z 2019, 'Cnnloc: Deep-learning based indoor localization with wifi fingerprinting', Proceedings - 2019 IEEE SmartWorld, Ubiquitous Intelligence and Computing, Advanced and Trusted Computing, Scalable Computing and Communications, Internet of People and Smart City Innovation, SmartWorld/UIC/ATC/SCALCOM/IOP/SCI 2019, IEEE SmartWorld, Ubiquitous Intelligence and Computing, Advanced and Trusted Computing, Scalable Computing and Communications, Internet of People and Smart City Innovation, IEEE, Leicester, United Kingdom, pp. 589-595.View/Download from: Publisher's site
© 2019 IEEE. With the ubiquitous deployment of wireless systems and pervasive availability of smart devices, indoor localization is empowering numerous location-based services. With the established radio maps, WiFi fingerprinting has become one of the most practical approaches to localize mobile users. However, most fingerprint-based localization algorithms are computationintensive, with heavy dependence on both offline training phase and online localization phase. In this paper, we propose CNNLoc, a Convolutional Neural Network (CNN) based indoor localization system with WiFi fingerprints for multi-building and multifloor localization. Specifically, we devise a novel classification model by combining a Stacked Auto-Encoder (SAE) with a onedimensional CNN. The SAE is utilized to precisely extract key features from sparse Received Signal Strength (RSS) data while the CNN is trained to effectively achieve high success rates in the positioning phase. We evaluate the proposed system on the UJIIndoorLoc dataset and Tampere dataset with several stateof-the-art methods. The results show CNNLoc outperforms the existing solutions with 100% and 95% success rates on buildinglevel localization and floor-level localization, respectively.
Cheng, Q, Dutkiewicz, Fang, G, Shi, Z, Nguyen, D & Wang, H 2017, 'A Novel Full-Duplex Spectrum Sensing Algorithm for OFDM Signals in Cognitive Radio Networks', GLOBECOM 2017 - 2017 IEEE Global Communications Conference, IEEE Global Communications Conference, IEEE, Singapore.View/Download from: Publisher's site
Full duplex (FD) capability enables a "listen and talk" protocol for spectrum sensing that has been used as a new paradigm to increase the spectrum utilization in cognitive radio networks (CRNs). However, the spectrum sensing performance suffers from the imperfect self-interference suppression (SIS). This could significantly degrade the performance of FD systems in CRNs. In this paper, we investigate the issue of spectrum sensing with imperfect SIS in FD systems. By drawing support from a cyclic prefix (CP) of Orthogonal Frequency Division Modulation (OFDM) signals, we propose a novel spectrum sensing mechanism that is robust to self- interference. Comparing with other conventional sensing approaches in FD systems, the proposed method is independent of timing delay. That significantly improves the sensing performance, even without requiring a complex process for timing delay estimation. As a result, it also reduces the overhead of spectrum sensing. Extensive simulation results indicate that even with serious self-interference and timing delay, the presented approach is still able to achieve much higher performance than the conventional energy detection and waveform-based detection approaches.
Cabrera, E, Fang, G & Vesilo, R 2017, 'Adaptive Hybrid ARQ (A-HARQ) for Ultra-Reliable Communication in 5G', IEEE Vehicular Technology Conference, IEEE Vehicular Technology Conference, IEEE, Sydney, NSW, Australia, pp. 1-6.View/Download from: Publisher's site
© 2017 IEEE. In this paper, we address the need for motivating applications, such as mission critical industrial control and medical applications, to operate under the Ultra-Reliable Communication (URC) mode in the future 5th Generation (5G) cellular wireless networks, while also under strict Quality of Service (QoS) constraints such as ultra-low latency. Reliability has been shown to improve by using Hybrid Automatic Repeat reQuest (HARQ) for the retransmission (RTX) of erroneous packets during poor channel conditions. However, this can increase the delay to unacceptable levels if more than 1 RTX is required. Thus, an Adaptive HARQ (A-HARQ) scheme is proposed, where RTX are done on better quality sub-bands, with resources dynamically allocated based on Channel Quality Indicator (CQI) reports. A-HARQ also increases the number of RTX within a 4 ms time period, by utilising Transmission Time Interval (TTI) bundling to decrease the delay incurred from many RTX. A performance analysis is conducted, where A-HARQ was shown to have about 35% lower delay than the legacy HARQ, with a slight decrease in throughput, for low Signal-to-Noise (SNR) values.
Li, X, Ma, L, Shankaran, R, Orgun, M & Fang, G 2017, 'Joint mode selection and proportional fair scheduling for D2D communication', IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC, Annual International Symposium on Personal, Indoor, and Mobile Radio Communication, IEEE, Montreal, QC, Canada, pp. 1-6.View/Download from: Publisher's site
© 2017 IEEE. In this paper, we propose a new joint mode selection and proportional fair scheduling scheme for Device-to-Device (D2D) communication in cellular networks. Our objective is to maximize the sum of all users' proportional fairness functions while guaranteeing the signal-to-interference-plus-noise ratio (SINR) requirements of both D2D and cellular links. In our scheme, we consider two communication mode options for D2D communication: the dedicated mode and the reuse mode. In order to improve the fairness of the D2D users (DUs), we allocate the dedicated radio resource to the D2D pair with a higher priority. Furthermore, we use the Hungarian Algorithm to implement the sub-optimal resource allocation for multiple D2D pairs in the reuse mode and their reuse cellular users (CUs). The simulation results demonstrate that both the system throughput and the system fairness experience significant increases in our proposed scheme.
Zhou, J, Dutkiewicz, E, Liu, RP, Fang, G & Liu, Y 2016, 'Target allocation of WSN based on Parallel Chaotic Elite Quantum-Inspired Evolutionary Algorithm', 2015 15th International Symposium on Communications and Information Technologies, ISCIT 2015, International Symposium on Communications and Information Technologies, IEEE, Nara Kasugano Int Forum IRAKA, Nara, JAPAN, pp. 287-290.View/Download from: Publisher's site
© 2015 IEEE. The target allocation problem is one of the important challenges in WSNs as sensor nodes have limited sensing and communication capabilities. In the target allocation problem, a set of targets is selected for each sensor to improve the monitoring quality as well as the energy efficiency. However, the target allocation problem is a combinatorial optimization problem, and the computational complexity is too high to consider all combinations for practical implementation. In this paper, we propose a novel Parallel Chaotic Elite Quantum-Inspired Evolutionary Algorithm (PCEQEA) for target allocation problem in WSNs. The PCEQEA combines the advantages of elite genetic algorithm and quantum-inspired evolutionary algorithm. It achieves high parallel search performance and fast convergence to global optimum solution. Simulation results demonstrate that proposed PCEQEA improves WSN detection coverage by detecting more targets than other existing schemes.
Cheng, Q, Fang, G, Nguyen, D & Dutkiewicz, E 2016, 'Novel Pilot Decontamination Methods for Massive MIMO Systems Under Practical Scenarios', 16th International Symposium on Communications and Information Technologies (ISCIT), International Symposium on Communications and Information Technologies, IEEE, Qingdao, PEOPLES R CHINA.View/Download from: Publisher's site
Accurate and efficient channel estimation methods have the ability to realize the theoretical gain in multi-input multi-output (Massive MIMO) systems which have a massive number of antennas. However, the pilot contamination in Massive MIMO channel estimation process, rooted from the pilot reuse, is a critical problem that severely degrades the performance of the system. This work aims to address the problem of pilot contamination in covariance-aided channel estimation methods while considering practical scenarios where the channel covariance matrices change due to a new user arrival and users mobility. To that end, we first design a method to track the channel covariance matrices and then use these estimated values in Bayesian estimation. Simulation results indicate that the normalized mean square error (NMSE) for both channel covariance matrices and the CSI itself of our proposed methods are much lower than those of classical methods based on least square (LS) and Bayesian estimation. Additionally, for the case that users move slowly (e.g., at walking speed), our proposed method can provide satisfactory performance for more than three times as much as classical Bayesian estimation before system re-train channel covariance matrices. In other words, compared with classical Bayesian methods, our proposed methods are able to get good system performance with less overhead and complexity by a lower frequency of re-training process.
He, Y, Dutkiewicz, E, Fang, G & Mueck, MD 2016, 'SNR threshold for distributed antenna systems in Cloud Radio Access Networks', 2015 IEEE 82nd Vehicular Technology Conference, VTC Fall 2015 - Proceedings, IEEE Vehicular Technology Conference, IEEE, Boston, MA.View/Download from: Publisher's site
© 2015 IEEE. A distributed antenna system (DAS) architecture is a key enabler for Cloud Radio Access Networks (CRAN) where geographically separated base stations are connected to a centralized processing and decision making unit. Many schemes have been proposed to leverage Fractional Frequency Reuse (FFR) and co-ordinated joint transmission between base stations to improve cell-edge performance for static network deployments. In this paper, we investigate dynamic decision making that whether co-ordinated joint transmission should be selected in the downlink of a FFR-aided DAS. We derive the transmitting Signal-to-Noise-Ratio (SNR) threshold that co-ordinated joint transmission can provide better performance if the transmitting SNR is below this threshold. We simulated a three-cell cluster layout with FFR and the numerical results agree with our analytical results. We show that the transmitting SNR threshold is critical in the FFR-aided DAS analysis and can be used as a guide in the CRAN network planning and the evaluation of DAS performance.
Saadat, A, Fang, G, Dutkiewicz, E, Mueck, M & Srikanteswara, S 2016, 'Enhanced QoS for domestic licensees in border areas through game theory based licensed shared access', 2016 16th International Symposium on Communications and Information Technologies, ISCIT 2016, International Symposium on Communications and Information Technologies, IEEE, Qingdao, PEOPLES R CHINA, pp. 44-47.View/Download from: Publisher's site
© 2016 IEEE.In this paper, we propose a non-coordinated Licensed Shared Access (LSA) model which enables Mobile Network Operators (MNOs) acting as domestic licensees to provide enhanced Quality of Service (QoS) in border areas. The proposed model allows the domestic licensees to rely on their backup strategies while utilizing available spectrum resources, to avoid severe interference and maintain their QoS, whenever foreign incumbents initiate their operation in similar frequency spectrum across the border. The proposed model is presented as an LSA based game theoretic algorithm. We prove its convergence to an equilibrium point after finite iterations, both analytically and through simulations.
Shrestha, S, Fang, G, Dutkiewicz, E & Huang, X 2016, 'Effect of CSI quantization on the average rate in MU-MIMO WLANs', Proceedings of the 2016 13th IEEE Annual Consumer Communications and Networking Conference, CCNC 2016, IEEE Consumer Communications and Networking Conference, IEEE, USA, pp. 824-828.View/Download from: Publisher's site
© 2016 IEEE.In Multi-User Multiple Input Multiple Output (MU-MIMO) Wireless Local Area Networks (WLANs), the optimal-solution such as Dirty Paper Coding (DPC) or the sub-optimal solution Zeroforcing Beamforming (ZFB) with perfect Channel State Information (CSI), is practically limited due to the complexity and the non-availability of perfect CSI at the Access Points (APs)/transmitters. In such a context, ZFB based on channel quantization available at the APs (ZFQ) is the obvious choice for the Multi-User transmission strategy. However, since the quantized CSI is used instead of the perfect CSI at the APs, the quantization error and its impact on the average rate for ZFQ have to be quantified in MU-MIMO WLAN settings. In this paper, we derive a closed-form expression for the upper bound of the channel quantization error and the average rate reduction due to the quantization error with respect to the perfect CSI at the APs. In MU-MIMO WLAN settings, our analytical and numerical studies show that, with an increasing number of antennas at the clients, both the quantization error bound and the average rate reduction increase for ZFQ, in comparison to the ZFB with the perfect CSI.
Wang, H, Dutkiewicz, E, Fang, G & Mueck, MD 2016, 'A Fair Spectrum Sharing Framework Based on Topological Sort and Max Weight for Femtocells', 2016 Australian Communications Theory Workshop, AusCTW 2016, Australian Communications Theory Workshop, IEEE, Monash University, Australia.View/Download from: Publisher's site
Femto base stations will be widely deployed in 5G times for compensating poor cellular coverage for use in residential or small business environments. In this paper, we propose a spectrum sharing framework, where a cluster of femtocells are under the control of a centralized local manager. The framework assumes that each femto base station has the sniffing ability that can detect its neighbor femtocells and the controller can then have complete knowledge of local interference constraints. Unlike distributed WiFi that runs on unlicensed band, the femtocell owned by a carrier runs on licensed band and the carrier prefers a centralized system to a distributed one. Therefore, a fair spectrum sharing policy on the licensed band is more important among carriers to break the monopoly and inefficient spectrum allocation. Considering the spectrum can be spatial reused, an interference graph is adopted to avoid the interference between femtocells of all the carriers. We test the framework not only by comparing the average number of channels per user can get but also the variance to guarantee the fairness. In this framework, the scheme combining topological sort and maximum traffic load of femtocell contributes to keep a better balance on the average number of channels and variance.
Wang, H, Dutkiewicz, E, Fang, G & Mueck, MD 2015, 'Spectrum sharing based on truthful auction in licensed shared access systems', 2015 IEEE 82nd Vehicular Technology Conference, VTC Fall 2015 - Proceedings, IEEE Vehicular Technology Conference, IEEE, USA.View/Download from: Publisher's site
© 2015 IEEE. The explosion of different types of wireless communications is leading to an impending spectrum famine. As a result, spectrum sharing has gained increasing interest from governments, industry and regulators, such as FCC in US and CEPT in Europe. Licensed Shared Access (LSA), developed by CEPT and ETSI, is a concept for an efficient use of current spectrum resources to enable keeping pace with increasing mobile data usage demands. In this paper, we present a truthful auction mechanism for spectrum sharing based on the LSA concept. This proposal is to allocate Incumbents' idle spectrum to Licensee Access Points from different operators for the purpose of commerce. We give insights into spectrum allocation methods based on auction mechanisms to obtain high revenue to attract Incumbents to join in the LSA architecture and operators to offload data from primary spectrum band. The proposed LSA Auction (LSAA) mechanism combines independent set selection by bidding and an elaborately designed group bid called Rank-bid, which further improves the revenue compared to related allocation methods. Our simulation results show that LSAA results in enhanced performance for Incumbent revenue and Licensee satisfaction.
Zhong, Y, Zhou, Z, Jiang, T, Heimlich, M, Dutkiewicz, E & Fang, G 2016, 'Classification of animals and people based on radio-sensor network', 2016 16th International Symposium on Communications and Information Technologies, ISCIT 2016, International Symposium on Communications and Information Technologies, IEEE, Qingdao, China, pp. 113-116.View/Download from: Publisher's site
© 2016 IEEE.Personnel detection embedded in foliage is extremely important to border patrol, perimeter protection and search-and-rescue operations. In this paper, we explore the utility of radio-sensor network (RSN) to distinguish between humans and animals. We explore the phenomenon that signals are always affected by the presence of obstacles and identify human based on the received signals by transceivers, which leads to a potential low-cost way for personnel detection without specific sensors. In our study, the impulse radio ultra-wideband (IR-UWB) technology is selected for the RF transceiver due to the fact that it is not only energy efficient, but also robust against interferences. The principle component analysis (PCA) is applied to extract the feature vector, and a support vector machine is used as the target classifier. Experiment result with an average accuracy of 97.5% based on actual data collected in a cornfield indicates that this approach has a good capability to distinguish between human and animals in a foliage environment.
Wang, W, Sun, Y, Uhlig, S, Fang, G, Wang, N & Li, Z 2016, 'Multipath Bandwidth Guarantees for Multi-Tenant Cloud Networking', Proceedings - Conference on Local Computer Networks, LCN, pp. 442-450.View/Download from: Publisher's site
© 2016 IEEE. Resource isolation of the computation and storage in the cloud is relatively mature, but the network resource is still shared among tenants leading to variable and unpredictable network performance when bandwidth guarantees are not enforced. Currently most of the bandwidth guarantee approaches are based on the idea of single-path reservation without fully exploiting the multipath resource, which leads to poor network utilization. In this paper, we propose a multi-path bandwidth guarantee approach called MultiBand, which provides bandwidth guarantees by allocating bandwidth across multiple paths. We utilize label-based routing technique to explicitly control the packets' transmission paths, and design a MHTB rate limiter model to split and schedule the traffic over the multiple reserved paths. Besides, Our Multiband solution has the work-conserving property. We evaluated our approach through simulations with realistic topologies and typical traffic patterns. Our results show that MultiBand is able to provide multipath bandwidth guarantees and to achieve higher network utility and tenant throughput compared with those of current approaches.
Zhou, J, Dutkiewicz, E, Liu, RP, Fang, G & Liu, Y 2014, 'Modified Elite Chaotic Immune Clonal Selection Algorithm for sever resource allocation in cloud computing systems', Proceedings of the 2014 International Symposium on Wireless Personal Multimedia Communications, International Symposium on Wireless Personal Multimedia Communications, IEEE, Sydney, Australia, pp. 226-231.View/Download from: Publisher's site
Cloud computing is a promising technology to improve computational efficiency for both IT enterprise and individuals. Resource allocation in cloud computing is very challenging as both server computing power and network bandwidth are limited. The computational efficiency of cloud computing system can be significantly improved if the resources are allocated in a balanced fashion. However, resource allocation in cloud computing is a multi-constrained nonlinear optimization problem. The computational complexity for an exhaustive search over all combinations of resource allocations is too high for practical implementation. In this paper, we develop a Modified Elite Chaotic Immune Clonal Selection Algorithm to increase the overall efficiency of the system. An elite strategy and chaotic approaches are designed to improve population diversity and escape from local optima. Performance comparisons are made with simulated annealing algorithm (SA) and three other heuristic algorithms. Simulation results show that the Modified Elite Chaotic Immune Clonal Selection Algorithm solves the resource allocation problem with higher system resource efficiency than all other heuristic algorithms.
Zhou, J, Dutkiewicz, E, Liu, RP, Fang, G, Liu, Y & Huang, X 2014, 'A modified shuffled frog leaping algorithm for PAPR reduction in OFDM systems', IEEE Region 10 Annual International Conference, Proceedings/TENCON, IEEE Tencon (IEEE Region 10 Conference), IEEE, Piscataway, USA.View/Download from: Publisher's site
© 2014 IEEE. Reducing peak-to-average power ratio (PAPR) is an implementation challenge in orthogonal frequency division multiplexing (OFDM) systems. One way to reduce PAPR is to apply a set of selected partial transmission sequence (PTS) to the transmit signals. However, PTS selection is a highly complex NP-hard problem and the computational complexity is very high when a large number of subcarriers are used in the OFDM system. In this paper, we propose a new heuristic PTS selection method, the modified chaos clonal shuffled frog leaping algorithm (MCCSFLA-PTS). The MCCSFLA-PTS is inspired by natural clonal selection of frog colony and based on chaos theory. Simulation results show that the proposed MCCSFLA-PTS achieves better PAPR reduction than genetic, quantum evolutionary and selective mapping algorithms. Furthermore, the proposed algorithm converges faster than the genetic and quantum evolutionary algorithms.
Zhou, J, Dutkiewicz, E, Liu, RP, Huang, X, Fang, G & Liu, Y 2014, 'Modified elite chaotic artificial fish swarm algorithm for PAPR reduction in OFDM systems', 14th International Symposium on Communications and Information Technologies, ISCIT 2014, International Symposium on Communications and Information Technologies, IEEE, Incheon Metropolitan City, Incheon, SOUTH KOREA, pp. 503-507.View/Download from: Publisher's site
© 2014 IEEE. Orthogonal frequency division multiplexing (OFDM) is a leading technology in the field of broadband wireless communications. In OFDM systems, a high peak-to-average power ratio (PAPR) is a critical issue, which may cause a nonlinear distortion and reduce power efficiency. To reduce the PAPR, partial transmit sequences (PTS) technique can be applied to the transmit data. However, the phase factor sequence selection in PTS technique is a non-linear optimization problem and it suffers from high complexity and memory use when there is a large number of non-overlapping sub-blocks in one symbol. In this paper a novel modified elite chaotic artificial fish swarm algorithm for PTS method (MECAFSA-PTS) is proposed to generate the optimum phase factors. The MECAFSA-PTS method is evaluated with extensive simulations and its performance is compared with quantum evolutionary and selective mapping algorithms. Our results show that the proposed MECAFSA-PTS algorithm is efficient in PAPR reduction.
Ding, J, Dutkiewicz, E, Huang, X & Fang, G 2015, 'Energy Efficient Cooperative Transmission in Single-Relay UWB Based Body Area Networks', IEEE International Conference on Communications, IEEE International Conference on Communications, IEEE, London, UK, pp. 1559-1564.View/Download from: Publisher's site
Energy efficiency is one of the most critical parameters in ultra-wideband (UWB) based wireless body area networks (WBANs). In this paper, the energy efficiency optimization problem is investigated for cooperative transmission with a single relay in UWB based WBANs. Two practical onbody transmission scenarios are taken into account, namely, along-torso scenario and around-torso scenario. With a proposed single-relay WBAN model, a joint optimal scheme for the energy efficiency optimization is developed, which not only derives the optimal power allocation but also seeks the corresponding optimal relay location for each scenario. Simulation results show that the utilization of a relay node is necessary for the energy efficient transmission in particular for the around-torso scenario and the relay location is an important parameter. With the joint optimal relay location and power allocation, the proposed scheme is able to achieve up to 30 times improvement compared to direct transmission in terms of the energy efficiency when the battery of the sensor node is very limited, which indicates that it is an effective way to prolong the network lifetime in WBANs.
Ding, J, Dutkiewicz, E, Huang, X & Fang, G 2015, 'Energy-efficient distributed beamforming in UWB based implant body area networks', IEEE Vehicular Technology Conference, IEEE Vehicular Technology Conference, IEEE, Glasgow, UK, pp. 1-5.View/Download from: Publisher's site
In this paper, we investigate a distributed beamforming problem to optimize energy efficiency (EE) in ultra-wideband (UWB) based implant body area networks (IBANs). To evaluate the impact of relay location on the EE, a relay location based cooperative network model is proposed, where multiple on-body relays are employed to assist an implant node to communicate with a BAN coordinator. With the proposed model, the EE optimization problem is mathematically formulated as a non-convex optimization problem. Sequential quadratic programming (SQP) combined with scatter search are applied to find the corresponding optimal solution. Simulation results illustrate that the proposed beamforming scheme outperforms other transmission schemes. A remarkable improvement can be achieved not only in EE but also in spectral efficiency (SE) compared to direct transmission. Moreover, numerical examples show that the relay location has a significant impact on the EE performance.
He, Y, Dutkiewicz, E, Fang, G & Mueck, MD 2015, 'Fractional Frequency Reuse in distributed antenna systems in Cloud Radio Access Networks', 2015 IEEE International Conference on Communication Workshop, ICCW 2015, IEEE International Conference on Communication Workshop, IEEE, London, ENGLAND, pp. 907-912.View/Download from: Publisher's site
© 2015 IEEE. A distributed antenna system (DAS) architecture is considered to be a key enabler for further Network Virtualization where different network configurations are created as needed by a centralized decision making unit that is typically integrated into the Cloud Radio Access Networks (C-RAN) which offers a potential architecture for 5G wireless communication systems. Many schemes have been proposed for Fractional Frequency Reuse (FFR) for resource allocation in the static cellular network architecture. In this paper, we investigate the effect of different FFR resource allocation approaches on the downlink cell edge users' capacity. We use a Multiset approach to model the resource allocation and interference. Targeting maximum average capacity, a closed-form lower bound of the average capacity is derived and the optimum FFR resource allocation is obtained. This provides a guide in the evaluation of DAS performance.
He, Y, Dutkiewicz, E, Fang, G & Mueck, MD 2014, 'Licensed Shared Access in distributed antenna systems enabling network virtualization', Proceedings of the 2014 1st International Conference on 5G for Ubiquitous Connectivity, 5GU 2014, International Conference on 5G for Ubiquitous Connectivity, IEEE, Akaslompolo, Finland, pp. 76-80.View/Download from: Publisher's site
© 2014 ICST. A distributed antenna system (DAS) architecture is considered to be a key enabler for further Network Virtualization where different network configurations are created as needed by a centralized decision making unit that is typically integrated into the Cloud Radio Access Network (C-RAN) which offers a potential architecture for 5G wireless communication systems. Many schemes have been proposed for Fractional Frequency Reuse (FFR) for resource allocation in the static cellular network architecture. In this paper, we investigate using the emerging Licensed Shared Access (LSA) on the downlink cell edge in a Network Virtualization context. We derive a threshold of the LSA bandwidth ratio for the average capacity and analyze the average capacity gain. This provides a guide in the decision making for using LSA bandwidth in DAS with Network Virtualization.
He, Y, Dutkiewicz, E, Fang, G & Shi, J 2014, 'Downlink capacity in Cloud Radio Access Networks with Fractional Frequency Reuse', International Symposium on Wireless Personal Multimedia Communications, WPMC, International Symposium on Wireless Personal Multimedia Communications, IEEE, Sydney, Australia, pp. 424-428.View/Download from: Publisher's site
© 2014 National Institute of Information and Communicatio. A distributed antenna system (DAS) architecture is believed to be able to enhance capacity performance of Cloud Radio Access Networks (C-RAN), especially for users near the cell boundary. Many schemes have been proposed to plan Fractional Frequency Reuse (FFR) on resource allocation. Some of them have leveraged the Coordinated multi-point transmission (CoMP) to improve the cell-edge performance. In this paper, we investigate and compare the capacity of Single User with Multiple-Input-Single-Output (SU-MISO) and Multiple Users with Multiple-Input-Multiple-Output (MU-MIMO) in C-RAN of multiple transmitting remote antenna units with FFR.
Shrestha, S, Fang, G, Dutkiewicz, E & Huang, X 2015, 'Addressing hidden terminals in WLANs with zero forcing coordinated beamforming', 14th International Symposium on Communications and Information Technologies, ISCIT 2014, International Symposium on Communications and Information Technologies, IEEE, Incheon Metropolitan City, Incheon, SOUTH KOREA, pp. 249-253.View/Download from: Publisher's site
© 2014 IEEE. We present here a new technique that can be used to address a well-known Hidden Terminal problem in Wireless Local Area Networks. Specifically, Zero Forcing Coordinated Beamforming can be applied, in a hidden terminal scenario, in order to null the signal of the interfering transmitter so that desired transmission can take place without collision at the receiver. Basically, a precoding range of a receiver is used as a determinant in order to take a nulling decisions based on the notion that a successful transmission depends on the interference free condition at the receiver. We demonstrate the feasibility of the approach in an USRP2/GNURadio test-bed prototype. Our scheme improves the SNR and Effective SNR from about 5 to 11 dB in a hidden terminal scenario and maintains collision free simultaneous transmissions.
Shrestha, S, Fang, G, Dutkiewicz, E & Huang, X 2015, 'Medium Access Control Protocol to Address Hidden Terminals in MU-MIMO WLANs', 2015 IEEE International Conference on Computer and Information Technology; Ubiquitous Computing and Communications; Dependable, Autonomic and Secure Computing; Pervasive Intelligence and Computing (CIT/IUCC/DASC/PICOM), International Workshop on Heterogeneous Wireless Networks and Quality-of-Experience, IEEE, Liverpool, UK, pp. 1638-1645.View/Download from: Publisher's site
We exploit the Degrees of Freedom (DoF) resulting from the deployment of multiple antennas, both at the Access Points (APs) and the clients, to address the Hidden Terminal problem in Multi User (MU) Multiple Input Multiple Output (MIMO) Wireless Local Area Networks (WLANs). This approach permits concurrent transmissions and is able to maintain a constant gain in network throughput in a Hidden Terminal scenario. We treat concurrent transmissions as an integral part of our design, so we adopt and extend the traditional Point Coordination Function (PCF) to manage them. Specifically, contention free period of the traditional PCF is used in uplink and downlink. In addition, based on DoF at APs, our MAC decides the Transmission Opportunity (TXOP) of APs/Transmitters in contrast to many traditional approaches. Besides, our MAC runs a concurrent algorithm at APs which forms an important part for the calculation of precoding vectors (based on the Zeroforcing) in the Physical Layer (PHY). Additionally, a seamless channel sounding process is designed to support the ZF precoding at the PHY which has 98.67μs signaling overhead, lower than IEEE802.11ac. Simulation studies in a typical 6-antenna AP and client scenario show that our MAC provides a remarkable constant network throughput gain of 4-5 times in comparison to traditional RTS/CTS, and a lower signaling overhead than IEEE802.11ac. Besides, our simple fairness algorithm provides a fair share in the throughput among APs, with the Jain Fairness Index greater than 90%.
Shrestha, S, Fang, G, Dutkiewicz, E & Huang, X 2015, 'Zeroforcing precoding based MAC design to address hidden terminals in MU-MIMO WLANs', 2015 22nd International Conference on Telecommunications, ICT 2015, IEEE International Conference on Telecommunications, IEEE, Sydney, AUSTRALIA, pp. 283-288.View/Download from: Publisher's site
© 2015 IEEE. This paper focuses on the Medium Access Control (MAC) layer design for an inevitable Hidden Terminal problem in Multi User Multiple Input Multiple Output (MU-MIMO) Wireless Local Area Networks (WLANs). Specifically, our MAC design is supported by the precoding vectors obtained by Zeroforcing technique which are used to address the Hidden Terminals. An efficient channel sounding process is used by our MAC protocol to obtain the Channel State Information (CSI) from the desired and undesired clients which are used to calculate the precoding vectors at the transmitters (Access Points). Our MAC design then uses these precoding vectors in order to null interferences among the undesired clients to avoid collision of signals and to maintain the concurrent transmissions among the desired clients. The the parameters such as network capacity, signaling overheads and fairness are considered in the design. Our MAC layer design shows a slightly higher signaling overhead compared to RTS/CTS scheme. However, due to the concurrent transmissions after the handshaking process, the cost of singling overheads are compensated. The simulation study of our MAC layer design shows a remarkable constant network capacity gain of 4-5 times in comparison to traditional RTS/CTS. Moreover, the gain is irrespective to the available air-time.
Wang, H, Dutkiewicz, E, Fang, G & Mueck, MD 2015, 'An auction framework based on flexible transmit powers in the Licensed Shared Access Systems', 2015 15th International Symposium on Communications and Information Technologies (ISCIT), International Symposium on Communications and Information Technologies, IEEE, Japan.View/Download from: Publisher's site
Wang, H, Dutkiewicz, E, Fang, G & Mueck, MD 2015, 'Framework of joint auction and mixed graph for Licensed Shared Access systems', 2015 IEEE International Symposium on Dynamic Spectrum Access Networks, DySPAN 2015, IEEE International Dynamic Spectrum Access Networks Symposium, IEEE, Stockholm, Sweden, pp. 154-163.View/Download from: Publisher's site
© 2015 IEEE. Licensed Shared Access offers an opportunity to further increase data rates in 5G networks. Considering that different commercial operators have no knowledge of each other, their base stations should be coordinated by a management entity to enable them to access the licensed shared spectrum without interference. An auction mechanism is often used as an efficient tool for resource allocation where rivalry is high. In this paper, we propose an on-line auction framework using a mixed graph due to the spatial reusability of spectrum. This proposed scheme allows each base station to make a concession by asking for a second shrinking interference-free area if its initial area overlaps some other base stations. We use a mixed graph to model the interference between them, because a mixed graph can quantify the interference much closer to the practical cases than an undirected graph does. We also propose to take the bid comparison into account when grouping the independent nodes in the interference graph. These two feathers together make the spectrum spatial efficiency improved, which leads to a higher revenue and a better buyer satisfaction.
Zheng, G, Fang, G, Orgun, MA, Shankaran, R & Dutkiewicz, E 2015, 'Securing wireless medical implants using an ECG-based secret data sharing scheme', 14th International Symposium on Communications and Information Technologies, ISCIT 2014, International Symposium on Communications and Information Technologies, IEEE, Incheon Metropolitan City, Incheon, SOUTH KOREA, pp. 373-377.View/Download from: Publisher's site
© 2014 IEEE. Wireless Implantable Medical Devices (IMDs), including pacemakers and cardiac defibrillators, often have built-in wireless modules in order to facilitate non-invasive programming and data read-out; however, most IMDs lack a security mechanism. The unique challenge is that IMDs should be able to be accessed by doctors at any legitimate hospital for emergency purposes, but conventional security mechanisms using keys or credentials cannot guarantee that doctors could obtain keys timely in emergency situations. To address this unique challenge, we present an ECG-based Secret Data Sharing (ESDS) scheme for securing wireless IMDs which does not require pre-deployed keys or credentials. The ESDS scheme makes use of electrocardiograph (ECG) features to hide a secret within the IMD before transmission, and then reveal the secret with simultaneously measured ECG features by an external programmer. This scheme can protect IMDs against eavesdropping and other active attacks. In addition, the scheme uses an improved fuzzy vault scheme in which hash functions are substituted for chaff points to hide genuine points on a polynomial. This improvement saves IMD resources in terms of memory and communications, making the ESDS scheme lightweight. Performance analysis shows that the ESDS scheme meets our design goal of security.
Saadat, A, Fang, G & Ni, W 2015, 'A Two-Tier Evolutionary Game Theoretic Approach to Dynamic Spectrum Sharing through Licensed Shared Access', CIT/IUCC/DASC/PICOM 2015 IEEE INTERNATIONAL CONFERENCE ON COMPUTER AND INFORMATION TECHNOLOGY - UBIQUITOUS COMPUTING AND COMMUNICATIONS - DEPENDABLE, AUTONOMIC AND SECURE COMPUTING - PERVASIVE INTELLIGENCE AND COMPUTING, IEEE International Conference on Computer and Information, IEEE, Liverpool, UNITED KINGDOM, pp. 6-11.View/Download from: Publisher's site
Zheng, G, Fang, G, Orgun, MA & Shankaran, R 2015, 'A comparison of key distribution schemes using fuzzy commitment and fuzzy vault within wireless body area networks', IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC, pp. 2120-2125.View/Download from: Publisher's site
© 2015 IEEE. The fuzzy commitment scheme and the fuzzy vault scheme have been widely investigated by researchers in the distribution of symmetric keys within a Wireless Body Area Network (WBAN) for security purposes. Both schemes could use the same physiological signal (Electrocardiogram) for the same purpose (key distribution). To provide guidance to researchers, this paper conducts a comparative analysis of these two schemes to identify their similarities and differences, and contrast their relative merits and demerits. In the paper, we present their mathematical models first, and then compare the models step by step together with an analysis of their simulation performance. According to our analysis, we find that both the techniques follow common workflows to conceal a symmetric key in a transmitter and reveal the key in a receiver, respectively. On the other hand, the fuzzy commitment scheme has a more complicated process in obtaining ECG measurements than the fuzzy vault scheme; by contrast, its key concealing and revealing process is much simpler when compared to the fuzzy vault scheme. Besides a superior False Acceptance Rate (FAR) performance of the fuzzy commitment scheme, their False Rejection Rate (FRR) performance is comparable. Since the polynomial calculation and reconstruction are utilized in the fuzzy vault scheme, from the perspective of the computational complexity, the fuzzy commitment scheme is recommended for lightweight WBAN sensors.
Zheng, G, Fang, G, Shankaran, R & Orgun, MA 2015, 'An Improved Binary Sequence Generation for Securing Wireless Body Area Networks', Proceedings - 2015 IEEE International Conference on Data Science and Data Intensive Systems; 8th IEEE International Conference Cyber, Physical and Social Computing; 11th IEEE International Conference on Green Computing and Communications and 8th IEEE International Conference on Internet of Things, DSDIS/CPSCom/GreenCom/iThings 2015, pp. 734-735.View/Download from: Publisher's site
© 2015 IEEE. Random Binary Sequences (BSS) play an important role in cryptographic algorithms. In order to secure Wireless Body Area Networks (WBANs), electrocardiogram (ECG) signal-based BS generation algorithms were studied in previous papers. These algorithms process Inter-pulse Intervals (IPIs) from the ECG signal, which normally needs about 20 to 30 seconds to generate a 128-bit BS. In order to improve the time efficiency of BS generation, we propose an improved algorithm which utilizes multiple types ECG features, including RR, RQ, RS, RP and RT intervals. This algorithm is faster than the IPI-based algorithms since it uses five types of ECG feature values in the BS generation.
Zhou, J, Dutkiewicz, E, Liu, RP, Fang, G & Liu, Y 2014, 'QoS routing based on parallel elite clonal quantum evolution for multimedia wireless sensor networks', IEEE Wireless Communications and Networking Conference, IEEE Wireless Communications and Networking Conference, IEEE, Istanbul, Turkey, pp. 2498-2503.View/Download from: Publisher's site
© 2014 IEEE. Quality of Service (QoS) routing is one of the key enabling techniques for multimedia wireless sensor networks (WSNs). However, the multi-constraints QoS routing problem is an NP-hard problem, and the computational complexity of an exhaustive search over all the paths is too high for large scale multimedia WSNs. In this paper, a novel parallel elite clonal quantum evolutionary algorithm is proposed to solve the multi-constraints QoS routing problem. The proposed algorithm minimizes the energy consumption, while guaranteeing QoS performance, including delay, bandwidth, delay jitter and packet loss rate, in multimedia WSNs. The algorithm is tested by extensive simulations and its performance is compared with the genetic algorithm and ant colony optimization. Simulation results demonstrate that the proposed algorithm achieves lower energy consumption at a faster convergence rate than the other two evolutionary algorithms.
Ding, J, Dutkiewicz, E, Huang, X & Fang, G 2014, 'Spectral efficiency optimization with distributed beamforming in UWB based implant body area networks', BODYNETS 2014 - 9th International Conference on Body Area Networks, BODYNETS 2014 - 9th International Conference on Body Area Networks, pp. 32-38.View/Download from: Publisher's site
Copyright © 2014 ICST. In this paper, a distributed beamforming problem is investigated based on spectral efficiency (SE) optimization for ultra-wideband (UWB) based implant body area networks (IBANs). We consider a relay network consisting of one implant source, several wearable relays, and one body network coordinator under the assumption that the individual relay power is constrained due to the Federal Communications Commission (FCC) regulations for UWB signals. Taking into account realistic wireless channels and relay locations, the SE optimization problem is mathematically formulated and solved by using convex optimization. Simulation results show that the proposed beamforming scheme is superior to other transmission schemes. Moreover, our numerical examples reveal that the relay location has a significant impact on the beamforming performance and the proposed beamforming scheme provides an efficient way to prolong the lifetime of the implant node.
He, Y, Dutkiewicz, E, Fang, G & Shi, J 2014, 'Differential capacity bounds for distributed antenna systems under low SNR conditions', 2014 IEEE International Conference on Communications, ICC 2014, IEEE International Conference on Communications, IEEE, Australia, pp. 5550-5554.View/Download from: Publisher's site
A distributed antenna system (DAS) architecture is believed to be able to enhance capacity performance of Cloud Radio Access Networks (C-RAN), especially for users near the cell boundary who experience low Signal-Noise-Ratio (SNR). However, the problem of finding the analytical bounds on the capacity of DAS with the rising number of antennas in low SNR rigime has not been fully studied. In this paper, we investigate a case in C-RAN of multiple transmitting base stations and a single receiving user under low SNR conditions. We derive closed-form upper and lower bounds in efficiently computable expressions for differential capacity (DCAP) using the moment generating function (MGF) of SNR. Bounds accuracy is evaluated and compared to results in current literature. Numerical results corroborate our analysis and the analytic bounds on DCAP is tight in the low SNR regime. Furthermore, The upper bound approximates better compared with the one obtained in  under two different channel models. These lower and upper bounds provide more accurate capacity measures which can be used in the evaluation of DAS performance and C-RAN design. © 2014 IEEE.
Jayawickrama, BA, Dutkiewicz, E, Oppermann, I, Mueck, M & Fang, G 2013, 'Downlink Power Allocation Algorithm for Licence-exempt LTE Systems Using Kriging and Compressive Sensing Based Spectrum Cartography', 2013 IEEE Global Communications Conference (GLOBECOM), IEEE Global Telecommunications Conference, IEEE, Atlanta, GA, USA.View/Download from: Publisher's site
Licence-exempt secondary Long Term Evolution systems have been proposed recently, in attempt to meet the needs of rapidly growing wireless mobile applications. However, where the secondary network is spread over a large geographical area, traditional detect-and-avoid algorithms are less effective in providing interference protection to Primary Users while maximising the secondary throughput. Spectrum cartography is an emerging technique that can be used to discover spectrum holes in space. We propose a downlink power allocation algorithm using Kriging Spatial Interpolation and Compressive Sensing based spectrum cartography in an environment where large scale shadow fading is prominent. We evaluate the performance of our approach by simulating a secondary Urban Microcell network operating in TV White Space. Simulation results show a significant improvement in interference and throughput, in comparison to traditional detect-and-avoid algorithms.
Yang, X, Cui, Q, Dutkiewicz, E, Huang, X, Tao, X & Fang, G 2014, 'Anti-noise-folding regularized subspace pursuit recovery algorithm for noisy sparse signals', 2014 IEEE Wireless Communications and Networking Conference (WCNC), IEEE Wireless Communications and Networking Conference, IEEE, Istanbul, Turkey, pp. 275-280.View/Download from: Publisher's site
© 2014 IEEE. Denoising recovery algorithms are very important for the development of compressed sensing (CS) theory and its applications. Considering the noise present in both the original sparse signal x and the compressive measurements y, we propose a novel denoising recovery algorithm, named Regularized Subspace Pursuit (RSP). Firstly, by introducing a data pre-processing operation, the proposed algorithm alleviates the noise-folding effect caused by the noise added to x. Then, the indices of the nonzero elements in x are identified by regularizing the chosen columns of the measurement matrix. Afterwards, the chosen indices are updated by retaining only the largest entries in the Minimum Mean Square Error (MMSE) estimated signal. Simulation results show that, compared with the traditional orthogonal matching pursuit (OMP) algorithm, the proposed RSP algorithm increases the successful recovery rate (and reduces the reconstruction error) by up to 50% and 86% (35% and 65%) in high noise level scenarios and inadequate measurements scenarios, respectively.
Zheng, G, Fang, G, Shankaran, R, Orgun, MA & Dutkiewicz, E 2014, 'An ECG-based Secret Data Sharing scheme supporting emergency treatment of Implantable Medical Devices', International Symposium on Wireless Personal Multimedia Communications, WPMC, International Symposium on Wireless Personal Multimedia Communications, IEEE, Sydney, Australia, pp. 624-628.View/Download from: Publisher's site
© 2014 National Institute of Information and Communicatio. The security issue of wireless Implantable Medical Devices (IMD) is an emerging area of research. The unique challenge here is that an IMD should be accessed by doctors with no authorization for emergency treatments while it still has to be protected from adversaries. In this paper, we propose a novel ECG-based Secret Data Sharing (ESDS) scheme in order to protect the IMD data privacy against eavesdropping and other active attacks from adversaries. The scheme establishes a secure wireless channel wherein the secret is encrypted with a random ECG bit string generated from real-time ECG signals. This secret can only be revealed by an IMD programmer which has the ability of measuring real-time ECG signals synchronously with the IMD. Since there is no pre-deployment of credentials, the IMD can be accessed by doctors without prior authorization. Performance analysis based on the real ECG data shows that the encrypted secret cannot be revealed by non-real-time or other patients' ECG signals; thus, it achieves our design goal of providing robust security.
Zheng, G, Fang, G, Orgun, MA & Shankaran, R 2014, 'A non-key based security scheme supporting emergency treatment of wireless implants', 2014 IEEE International Conference on Communications, ICC 2014, pp. 647-652.View/Download from: Publisher's site
The security of wireless communication module for Implantable Medical Devices (IMDs) poses a unique challenge that doctors in any qualified hospital should have the access to the IMDs for an emergency treatment while the IMD should be protected from adversaries during a patient's daily life. In this paper, we present a non-key based security scheme for the emergency treatment of IMDs, named the BodyDouble. This scheme employs an external authentication proxy embedded in a gateway to authenticate the identity of a programmer. The gateway here employs a transmitting antenna to send data and jamming signals. When an adversary launches attacks, the gateway jams the request signal to the IMD and authenticates its identity. The gateway will also pretend to be the wireless module of the IMD by establishing a communication link with the adversary so that the adversary is spoofed to communicate with the gateway instead of the IMD. For the emergency situation, the IMD can be accessed without using any cryptographic keys by simply powering off or removing the gateway. Simulation results show that this security scheme can protect the IMD from the adversary's attacks successfully, and resist the potential repeated attacks to prevent the battery depletion of the IMD. © 2014 IEEE.
Ding, J, Dutkiewicz, E, Huang, X & Fang, G 2013, 'Energy-efficient cooperative relay selection for UWB based body area networks', 2013 IEEE International Conference on Ultra-Wideband, ICUWB 2013, IEEE International Conference on Ultra-Wideband (ICUWB), IEEE, Sydney, NSW, Australia, pp. 97-102.View/Download from: Publisher's site
In this paper, an energy-efficient cooperative relay selection scheme is investigated for ultra-wideband (UWB) based wireless body area networks (WBANs). With a realistic nonlinear energy consumption model, the energy consumption for single-relay cooperation is established and the optimal power allocation for cooperation is derived accordingly to minimize the total energy consumption at a given relay location. Afterwards, an energy efficient relay selection criterion is described in detail. Simulation results verify the suitability of the criterion and show that, with the same desired spectral efficiency (SE), direct transmission is preferable for energy saving when the transmitter and receiver are located on the same side of the human body. However, at a suitable relay location and with large transmission distance, cooperative transmission can achieve a significant improvement on energy efficiency compared with direct transmission when the transmitter and receiver are located on the different sides of the human body. © 2013 IEEE.
Jayawickrama, BA, Dutkiewicz, E, Oppermann, I, Fang, G & Ding, J 2013, 'Improved performance of spectrum cartography based on compressive sensing in cognitive radio networks', 2013 IEEE International Conference on Communications (ICC), IEEE International Conference on Communications, IEEE, Budapest, Hungary.View/Download from: Publisher's site
Spectrum cartography is the process of constructing a map showing Radio Frequency signal strength over a finite geographical area. Multiple research groups have recently proposed to use spectrum cartography in the context of discovering spectrum holes in space that can be exploited locally in cognitive radio networks. In our novel approach, we exploit the sparsity of primary users in space to formulate the cartography process as a compressive sensing problem. Further, we present a novel algorithm for solving the cartography problem that builds on the well-known Orthogonal Matching Pursuit algorithm. We evaluate the performance of our approach by simulating a cognitive radio network where primary users are low power wireless microphones. Our simulation results show a significant improvement in reconstruction error, in comparison to two existing compressive sensing based methods.
Yang, X, Dutkiewicz, E, Cui, Q, Huang, X, Tao, X & Fang, G 2013, 'Analog compressed sensing for multiband signals with non-modulated Slepian basis', IEEE International Conference on Communications, IEEE International Conference on Communications, IEEE, Budapest, Hungary, pp. 4941-4945.View/Download from: Publisher's site
Recently, the recovery performance of analog Compressed Sensing (CS) has been significantly improved by representing multiband signals with the modulated and merged Slepian basis (MM-Slepian dictionary), which avoids the frequency leakage effect of the Discrete Fourier Transform (DFT) basis. However, the MM-Slepian dictionary has a very large scale and corresponds to a large-scale measurement matrix, which leads to high recovery computational complexity. This paper resolves the above problem by modulating and band-limiting the multiband signal rather than modulating the Slepian basis. Specifically, instead of using the MM-Slepian dictionary to represent the whole multiband signal, we propose to use the non-modulated Slepian basis to represent the modulated and band-limited version of the multiband signal based on the recently proposed Modulated Wideband Converter (MWC). Furthermore, based on the analytical derivation with the non-modulated Slepian basis, we propose an Interpolation Recovery (IR) algorithm to take full advantage of the Slepian basis, whereas the Direct Recovery (DR) algorithm using the Moore-Penrose pseudo-inverse cannot achieve this. Simulation results verify that, with low recovery computational load, the non-modulated Slepian basis combined with the IR algorithm improves the recovery SNR by up to 35 dB compared with the DFT basis in noise-free environment. © 2013 IEEE.
Yang, Y, Fang, G, Dutkiewicz, E & Li, Y 2013, 'A new 3D statistical method for mobile channel model', Advances in Intelligent Systems and Computing, IEEE Congress on Evolutionary Computation, Springer, China, pp. 945-951.View/Download from: Publisher's site
3-dimension statistical method is used to simulate the popular micro-cell propagation model: COST231-Walfish-Ikegami model . The extended model allows for improved path loss estimation by consideration the character of the urban environment parameters are lognormal random variables rather than deterministic. The numerical calculation results and trial measurement data is presented. Based on the measurement and modelling results, we find that the 3D COST231-WI model fits very well with the measurement result in the metropolitan scenario. The conclusion is useful and helpful to network planning in the future. © 2013 Springer-Verlag.
Huq, MA, Dutkiewicz, E, Fang, G, Liu, RP & Vesilo, R 2012, 'MEB MAC: Improved channel access scheme for medical emergency traffic in WBAN', 2012 International Symposium on Communications and Information Technologies, ISCIT 2012, International Symposium on Communications and Information Technologies, IEEE Xplore, Gold Coast, QLD, Australia, pp. 371-376.View/Download from: Publisher's site
Emergency data delivery is an important service for medical Wireless Body Area Networks. The successful dissemination of emergency messages can make a huge difference between life and death. The utmost importance of emergency message dissemination requires high reliability while the intermittent nature of alarms requires minimum channel access delay for almost instantaneous delivery. IEEE 802.15.6 beacon enabled networks have defined an adjustable superframe structure that consists of contention-free and contention access periods. Short superframes can satisfy the channel access delay requirements of emergency traffic but penalizes the energy efficiency of all devices in the network. On the other hand, long superframes increase the energy efficiency but the channel access delay is also increased. To balance this contradicting requirement of energy efficiency and Quality of Service, we propose the Medical Emergency Body (MEB) MAC protocol that inserts listening windows dynamically within the contention free periods. The frequency of listening window insertion is determined by the minimum delay tolerance. Furthermore, MEB MAC utilizes idle time slots to insert additional listening window opportunities for emergency traffic, without affecting the network throughput. Our analysis shows that MEB MAC is able to reduce channel access delay for emergency traffic especially for long superframe durations. Simulation results show the effectiveness of the MEB MAC scheme in serving emergency messages in medical body area networks. © 2012 IEEE.
Jayawickrama, BA, Dutkiewicz, E & Fang, G 2012, 'Spectrum Sensing Error Optimisation in Cognitive Radio Networks', 2012 International Symposium on Communications and Information Technologies, ISCIT 2012, International Symposium on Communications and Information Technologies, IEEE, Gold Coast, Australia.View/Download from: Publisher's site
Yang, Y, Fang, G, Dutkiewicz, E & Shen, D 2012, 'Statistical characterization of the 400 MHz in-body propagation channel in in-door environments', 2012 International Symposium on Communications and Information Technologies, ISCIT 2012, International Symposium on Communications and Information Technologies, IEEE Xplore, Gold Coast, QLD, Australia, pp. 48-53.View/Download from: Publisher's site
Channel modeling is the starting point of effective, efficient body-centric communications. Many efforts - have been made to characterize the on-body area propagation channel in static scenarios at various frequency bands in an anechoic chamber. This paper presents an experimental investigation into the in-body channel in 400 MHz MICS Band. By taking into account the joint effect of human movement and multipath effects, the measurements have been conducted in a populated office at very short distances. The dynamic channel behaviour has been captured and based on the statistical analyses of fading duration, a six-state Semi-markov model that considers both Line of Sight (LOS) and Non Line of Sight (NLOS) cases is proposed. Parameters of the Semi-markov model are estimated from the measured data. The validity of this model is confirmed by comparison of the first order and second order statistics of the proposed model with the measured data. © 2012 IEEE.
This paper presents an experimental investigation into the in-body channel in 400 MHz MICS Band. By taking into account the joint effect of human movement and multipath effects, the measurements have been conducted in a populated office at very short distances. The dynamic channel behaviour has been captured and based on the statistical analyses of fading duration, a six-state Semi-markov model that considers both Line of Sight (LOS) and Non Line of Sight (NLOS) cases is proposed. Parameters of the Semi-markov model are estimated from the measured data. The validity of this model is confirmed by comparison of the first order and second order statistics of the proposed model with the measured data. © 2012 IEEE.
Lai, J, Dutkiewicz, E, Liu, RP, Vesilo, R & Fang, G 2011, 'Network selection in cooperative cognitive radio networks', 11th International Symposium on Communications and Information Technologies, ISCIT 2011, International Symposium on Communications and Information Technologies, IEEE, Hangzhou, China, pp. 378-383.View/Download from: Publisher's site
This paper studies network selection issues in cooperative cognitive radio networks (CRNs) where secondary users (SUs) have access to the combined spectrum pool of cooperating CRNs. Motivated by the service degradation of SUs caused by unnecessary network handover in cooperative CRNs, we formulate the network selection problem as a nonlinear optimization problem to minimize overall SU handover probability. We subsequently propose three network selection schemes and theoretically evaluate their performance using corresponding Markov chain models. Our numerical results indicate that a jointly-optimized network selection scheme which takes into account both the number of free channels and the traffic intensity of primary users in each CRN obtains the lowest probability of SU handover. Furthermore, compared to the random selection scheme, the jointly-optimized network selection scheme achieves significant reduction in SU handover probability while having no negative impact on other performance metrics of secondary users, such as blocking probability, forced termination probability and completion probability. © 2011 IEEE.
Zheng, C, Dutkiewicz, E, Liu, RP, Vesilo, R, Fang, G & Zhou, Z 2011, 'Opportunistic routing in multi-channel cognitive radio networks', 11th International Symposium on Communications and Information Technologies, ISCIT 2011, International Symposium on Communications and Information Technologies, IEEE, Hangzhou, China, pp. 532-537.View/Download from: Publisher's site
Cognitive radio (CR) is an exciting technology to improve spectrum utilization. However, spectrum availability can change very fast due to primary user's activity, which makes most of existing CR routing protocols fail to work because they are designed for cognitive radio networks (CRNs) with slow variation of spectrum availability. Opportunistic routing is a promising routing paradigm for CRNs with fast variation of spectrum availability. We propose a multi-channel spectrum aware opportunistic routing (MSAOR) algorithm based on link delay analysis. By introducing channel access probability to characterize the opportunistic CR link, access delay is integrated into queuing delay. Our analysis shows that our algorithm achieves a lower link delay than the existing routing algorithm SAOR (spectrum aware opportunistic routing). Our simulation results also show that our MSAOR algorithm can reduce end-to-end delay by up to 50%, can increase the supported offered load by up to 190% and is more robust than SAOR. © 2011 IEEE.
Fang, G, Dutkiewicz, E, Huq, MA, Vesilo, R & Yang, Y 2011, 'Medical body area networks: Opportunities, challenges and practices', 11th International Symposium on Communications and Information Technologies, ISCIT 2011, International Symposium on Communications and Information Technologies, IEEE, Hangzhou, China, pp. 562-567.View/Download from: Publisher's site
Medical Body Area Network (MBAN) is a new wireless communications technology designed to sense human's vital signals through tiny nodes in, on and around the human body wirelessly. MBAN will play an important role in enabling ubiquitous and non-invasive telemetry and healthcare systems in the future. In this paper, we firstly explore the opportunities of MBAN from the point of new applications, and then we analyze the enabling technologies and challenges to achieve the goal of MBAN, which includes energy efficiency, robustness, high data rate for video support and network co-existence issues. Finally, we describe our MQWIN400 radio platform which was designed to work at 400MHz MICS band, as well as the related research activities and experimental results. © 2011 IEEE.
Zhai, H, Jiang, H, Sun, Y, Li, J, Liu, J, Fang, G & Dutkiewicz, E 2011, 'LHCDS: A novel deployment strategy of proxy caches for P2P traffic in ISP networks', Proceedings - 11th IEEE International Conference on Computer and Information Technology, CIT 2011, International Conference on Communications and Information Technology, IEEE, Pafos, Cyprus, pp. 224-230.View/Download from: Publisher's site
Peer-to-Peer (P2P) systems have brought two serious problems for Internet Services Providers (ISPs): traffic surges and network congestion. Proxy caching for P2P traffic is an effective means of easing the burden imposed by P2P traffic on ISPs. The deployment strategy of proxy caches has a significant impact on their effect on ISPs. It has two important components: one is cache operation that is what P2P traffic caches monitor and serve; the other is cache deployment algorithm that is where to deploy caches. In this paper, we propose a deployment strategy of proxy caches, called LHCDS (Cache Deployment Strategy for Lower and Higher networks), including a new type of cache operation and its corresponding deployment algorithm. It can serve P2P traffic not only from the local lower access network to the higher transit ISP's network but also within the higher transit ISP's network itself. In LHCDS, caches are deployed at or near core routers of the transit ISP. We develop several deployment algorithms based on the new cache operation. We then evaluate the algorithms, and conclude that the proposed greedy algorithm is a viable and practical algorithm whose performance is close to optimal. Experiments also show that ISPs can achieve more P2P traffic decrease on links using LHCDS than previous strategies. © 2011 IEEE.
Fang, G, Dutkiewicz, E, Yu, K, Vesilo, R & Yu, Y 2010, 'Distributed inter-network interference coordination for wireless body area networks', GLOBECOM - IEEE Global Telecommunications Conference.View/Download from: Publisher's site
In this paper we consider the inter-network interference problem in Wireless Body Area Networks (WBANs). We propose a distributed inter-network interference aware power control algorithm motivated by game theory. A power control game is formulated considering both interference between nearby networks and energy efficiency of WBANs. We derive a distributed power control algorithm called ProActive Power Update (PAPU), which can efficiently find the Nash Equilibrium representing the best tradeoff between energy and network utility. A realistic power control procedure is proposed assuming limited cooperation between WBANs. We compare our algorithm with the ADP algorithm where users are punished for interfering with others and we show that our solution can utilize energy much more efficiently by only sacrificing a small amount of network utility. In addition, we show that by adjusting the energy price, PAPU provides a methodology for application scenarios where WBANs have different energy constraints and quality of service requirements. ©2010 IEEE.
Kazemi, R, Vesilo, R, Dutkiewicz, E & Fang, G 2010, 'Inter-network interference mitigation in wireless body area networks using power control games', ISCIT 2010 - 2010 10th International Symposium on Communications and Information Technologies, pp. 81-86.View/Download from: Publisher's site
In this paper, we propose a non-cooperative power control game to mitigate inter-network interference in Wireless Body Area Networks (WBANs), which use emerging short-range wireless communication technology inside, on or around the human body for healthcare, entertainment and ubiquitous computing purposes. Interference endangers the reliability of WBANs especially in critical medical applications and also leads to more power consumption in very energy-constrained WBANs. Coordinating transmission power levels, we increase the system total throughput in the presence of interference using as little power as possible. We utilize non-linear and adaptive power pricing functions to penalize high power users and increase capacity in better channels. We investigate the Nash equilibrium existence and uniqueness and propose the best response strategy in the game to reach the Nash equilibrium. ©2010 IEEE.
Tian, L, Pang, D, Yang, Y, Shi, J, Fang, G & Dutkiewicz, E 2010, 'Subcarrier allocation for multicast services in multicarrier wireless systems with QoS guarantees', IEEE Wireless Communications and Networking Conference, WCNC.View/Download from: Publisher's site
The throughput of conventional multicast transmission in wireless systems is limited by the user with the worst channel quality in the multicast service group. The subcarrier allocation for multicast services in multicarrier systems is a feasible solution to overcome the capacity limitation by exploiting the frequency diversity among subcarriers. However, most of the current subcarrier allocation algorithms are limited to unicast services. In this paper, we propose an optimal subcarrier allocation algorithm for multicast services with Quality of Services (QoS) guarantees. A low-complexity suboptimal algorithm is also proposed, which includes three steps: Conservative Allocation, Greedy Step and Iterative Enhancement. Simulation results show that the proposed algorithms significantly outperform the conventional multicast transmission scheme while at the same time guaranteeing the minimum data rates of all users. Moreover, simulation results also show that the performance difference between the optimal and suboptimal algorithms is small. ©2010 IEEE.
Yu, K, Fang, G & Dutkiewicz, E 2010, 'Position and orientation accuracy analysis for wireless endoscope magnetic field based localization system design', IEEE Wireless Communications and Networking Conference, WCNC.View/Download from: Publisher's site
This paper focuses on wireless capsule endoscope magnetic field based localization by using a linear algorithm, an unconstrained optimization method and a constrained optimization method. Eight sensor populations are employed for performance evaluation. For each of five sensor populations, four different sensor configurations are investigated, which represent potential sensor placements in practice. Accuracy is evaluated over a range of noise standard deviations and the position area is set on a solid cylinder which well represents the realistic scenario of the human body. It is observed that the optimization method greatly outperforms the linear algorithm that should not be used alone in general. The constrained optimization approach outperforms the unconstrained optimization method in presence of large noise. Simulation results show that best position accuracy is achieved when the sensors are uniformly deployed on a 2D plane with some sensors on the boundary of the position area. For the sensor populations considered, when increasing sensor population by one, the accuracy improves by about 0.45 divided by the sensor population. The results provide useful information for the design of wireless endoscope localization systems. ©2010 IEEE.
Yu, Y, Dutkiewicz, E, Huang, X, Mueck, M & Fang, G 2010, 'Performance analysis of soft frequency reuse for inter-cell interference coordination in LTE networks', ISCIT 2010 - 2010 10th International Symposium on Communications and Information Technologies, pp. 504-509.View/Download from: Publisher's site
Due to the requirement of high spectrum efficiency, the frequency reuse of one is targeted for next generation OFDMA-based cellular networks. Such a frequency planning strategy can lead to unacceptable inter-cell interference levels experienced especially by users located at the cell edge area. Soft frequency reuse (SFR) is considered as an effective frequency reuse scheme for inter-cell interference coordination as well as maintaining spectrum efficiency. In this paper, we investigate the performance of SFR for LTE downlink transmission by considering issues of various traffic loads and different power ratio configurations. In addition to the cell-edge user performance, the overall cell performance and the cell-center user performance are both evaluated in terms of throughput estimation. Using simulation studies, the advantages and limitations of SFR are comprehensively examined and compared against the classical frequency reuse of one scheme. ©2010 IEEE.
Yuan, Y, Zhang, Z, Li, J, Shi, J, Zhou, J, Fang, G & Dutkiewicz, E 2010, 'Extension of SCTP for concurrent multi-path transfer with parallel subflows', IEEE Wireless Communications and Networking Conference, WCNC.View/Download from: Publisher's site
With its new features such as multi-homing and multi-streaming the Stream Control Transmission Protocol (SCTP) has become a promising candidate as a general-purpose transport layer protocol. Multi-homing in an SCTP association can make concurrent multi-path transfer an appealing candidate to satisfy the ever increasing user demands for bandwidth. Multiple streams provide an aggregation mechanism to accommodate heterogeneous objects, which belong to the same application but may require different QoS from the network. However, the current approach lacks an internal mechanism to support preferential treatment among its streams for concurrent multipath transfer. In this paper, we introduce WM2-SCTP (Wireless Multi-path Multi-flow - Stream Control Transmission Protocol), a transport layer solution for concurrent multi-path transfer with parallel subflows. WM2-SCTP aims at exploiting SCTP's multi-homing and multi-streaming capability by grouping SCTP streams into subflows based on their required QoS and selecting best paths for each subflow to improve data transfer rates. The results show that under different scenarios WM2-SCTP, can effectively enhance transmission efficiency. ©2010 IEEE.
Fang, G & Dutkiewicz, E 2009, 'BodyMAC: Energy efficient TDMA-based MAC protocol for wireless body area networks', 2009 9th International Symposium on Communications and Information Technology, ISCIT 2009, pp. 1455-1459.View/Download from: Publisher's site
Wireless Body Area Networks (WBANs) enable placement of tiny biomedical sensors on or inside the human body to monitor vital body signs. The IEEE 802.15.6 task group is developing a standard to optimize WBAN performance by defining the physical layer (PHY) and media access control (MAC) layer specifications. In this paper an energy efficient MAC protocol (BodyMAC) is proposed. It uses flexible bandwidth allocation to improve node energy efficiency by reducing the possibility of packet collisions and by reducing radio transmission times, idle listening and control packets overhead. BodyMAC is based on a Downlink and Uplink scheme in which the Contention Free Part in the Uplink subframe is completely collision free. Three types of bandwidth allocation mechanisms allow for flexible and efficient data and control communications. An efficient Sleep Mode is introduced to reduce the idle listening duration, especially for low duty cycle nodes in the network. Simulation results show superior performance of BodyMAC compared to that of the IEEE 802.15.4 MAC. ©2009 IEEE.
Shi, J, Jin, X, Dong, J, Huang, Y, Zhou, J & Fang, G 2009, 'A QoS-aware interference balancing scheme for multiuser MIMO systems', IEEE Vehicular Technology Conference.View/Download from: Publisher's site
In multiuser MIMO systems, the achievable system data rate as well as quality of service (QoS) of individual users is limited by the inter-user interference (IUI). The interference balancing issue via power allocation can be usually formulated as a nonconvex optimization problem which will become more intractable with nonconvex QoS constraints. In this paper we focus on the challenging QoS-aware optimal power allocation problem, aiming to maximize the system sum rate and guarantee the users' minimum data rates. As a result, a "Posynomial Approximations based on Single Condensation" (PASC) strategy is proposed which transforms the underlying problem to a series of tractable Geometric Programming (GP) problems through single condensation scheme. Extensive simulations have been conducted and the results indicate that PASC is quite suitable to tackle the problem, which can achieve a good balance between the system sum rate and the individual QoS requirements. © 2009 IEEE.
Sun, Y, Feng, B, Zhang, Y, Fang, G, Shi, J & Dutkiewicz, E 2007, 'Fast RSVP: A cross layer resource reservation scheme for mobile IPv6 networks', Proceedings - IEEE Symposium on Computers and Communications, pp. 691-697.View/Download from: Publisher's site
This paper proposes a new cross layer scheme (Fast RSVP) to reserve resources in mobile IPv6 networks. Through the cooperation of mobile IP and RSVP modules, Fast RSVP includes a number of mechanisms such as advanced resource reservation on neighbor tunnels, resource reservation on optimized routes, resource reservation for handover sessions, path merge etc. Network simulation results show that our scheme, compared with other traditional ways to reserve resources in mobile environments, has the following advantages: (1) it allows a mobile node to realize fast handover with QoS guarantees; (2) it avoids resource wasting caused by triangular routes and duplicate reservations; (3) it distinguishes different types of reservation requests, greatly reducing the handover session forced termination rate while maintaining high performance of the network. © 2007 IEEE.
Tian, L, Yang, Y, Shi, J, Dutkiewicz, E & Fang, G 2007, 'Energy efficient integrated scheduling of unicast and multicast traffic in 802.16e WMANs', GLOBECOM 2007: 2007 IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE, VOLS 1-11, IEEE Global Telecommunications Conference (GLOBECOM 07), IEEE, Washington, DC, pp. 3478-+.
Yang, Y, Tian, L, Fang, G, Shi, J & Li, Z 2007, 'A QoS aware eigenmode based power allocation scheme for MIMO-OFDM multi-user systems', GLOBECOM - IEEE Global Telecommunications Conference, pp. 3164-3168.View/Download from: Publisher's site
In this paper, a practical eigenmode based scheduling algorithm with double loops (ESDL) is proposed for multi-user MIMO/OFDM systems. The wireless channels are decomposed into several eigenmodes, and the eigenmode based power allocation is formulated into an optimization problem, whose object is to maximize the system capacity while guaranteeing users' QoS requirements. By replacing the QoS constraints with penalty functions, the problem is reformulated to a penalty problem with a given penalty factor, which is solved by a greedy power allocation (GPA) scheme as the inner loop. The penalty factor is then updated in the outer loop according to QoS constraints. Numerical results show that compared with other algorithms proposed in the literature, ESDL can result in significant improvement in channel efficiency, while at the same time guaranteeing minimum data rates of users. © 2007 IEEE.
Fang, G, Shi, J & Dutkiewicz, E 2006, 'Channel efficiency aware scheduling algorithm for real-time services in wireless networks', Proceedings of the 1st IEEE International Conference on Wireless Broadband and Ultra Wideband Communications, AusWireless 2006, pp. 102-107.
In this paper, we consider the problem of scheduling real time services over time-varying wireless links in broad-band wireless networks where an Adaptive Modulation and Coding (AMC) scheme is applied in the physical layer in order to decrease the packet error rate. It is well known that a properly chosen modulation and coding scheme can increase error robustness in the physical layer. However, this is at the expense of higher system complexity and decreased channel efficiency. We present a novel Near Maximum Weighted Bipartite Matching (NMWBM) scheduling algorithm, which schedules real time services in accordance with delay bounds and physi-cal layer modulation and coding modes. Numerical re-sults set in the context of IEEE 802.16 networks show that NMWBM can improve system packet throughput and pro-vide higher channel efficiency compared to the existing Earliest Deadline First scheduling algorithm. NMWBM provides this improved performance while meeting delay bound and packet loss rate requirements of real time ser-vices in broadband wireless networks.
Fang, G, Sun, Y, Zhou, J, Shi, J, Li, Z & Dutkiewicz, E 2006, 'Subcarrier allocation for OFDMA wireless channels using lagrangian relaxation methods', GLOBECOM - IEEE Global Telecommunications Conference.View/Download from: Publisher's site
In this paper, we propose a practically efficient Subcarrier Allocation scheme based on Lagrangian relaxation to solve the problem of subcarrier allocation in OFDMA wireless channels. The problem of subcarrier allocation is formulated into an Integer Programming (IP) problem, which is relaxed by replacing complicating constraints with Lagrange multipliers using Lagrangian Relaxation. A subgradient method is used to optimize the Lagrangian dual function and a heuristic is designed to obtain the feasible solution. Lagrangian Relaxation Subcarrier Allocation (LRSA) is proven to be of polynomial complexity and it provides bounds on the value of channel efficiency. Numerical results show that compared with other algorithms proposed in the literature, LRSA can result in a significant improvement in channel efficiency, while at the same time guaranteeing minimum data rates of users. ©2006 IEEE.
Fang, G, Yang, F, Shi, J & Dutkiewicz, E 2006, 'Subcarrier allocation with minimum data rate constraint in OFDMA wireless channels', Proceedings of the 1st IEEE International Conference on Wireless Broadband and Ultra Wideband Communications, AusWireless 2006, pp. 351-356.
In this paper, we present a novel and efficient Subcarrire Allocation algorithm with Minimum Data RAte (SAMDRA) constraint for multiuers orthogonal frequency division multiple access (OFDMA) wireless networks. The proposed algorithm attempts to exploit both the time diversity and frequency diversity in the wireless channel. A concept of service expectation is used to indicate how users hope to be served and have their quality of service (QoS) guaranteed. The subcarrier allocation problem is decomposed into two stages. The first stage is to decide which user to be served based on the service expectation and channel quality of users. In the second stage, a sub-carrier is chosen for the current user in order to maxi-mize the average data rate. Numerical results demon-strate a significant improvement in the average date rate under the constraint of minimum data rate guarantee for users.
Gengfa, F, Yi, S, Jihua, Z, Jinglin, S & Dutkiewicz, E 2006, 'Generic scheduling framework and algorithm for time-varying wireless networks', IEEE Vehicular Technology Conference, pp. 1157-1161.View/Download from: Publisher's site
In this paper, the problem of scheduling multiple users sharing a time varying wireless channel is studied, in networks such as in 3G CDMA and IEEE 802.16. We propose a new generic Wireless Packet Scheduling Framework (WPSF), which takes into account not only the quality of service (QoS) requirements but also the wireless resource consumed. The framework is generic in the sense that it can be used with different resource constraints and QoS requirements depending on the traffic flow types. Subsequently, based on this framework a Minimum Rate and Channel Aware (MRCA) scheduling algorithm is presented. MRCA attempts to greedily enhance wireless channel efficiency by making use of multi-user channel quality diversity, while providing acceptable QoS in term of users' minimum rate constraints. Simulation results show the desirable properties identified in the algorithm. © 2006 IEEE.
Shi, J, Fang, G, Sun, Y, Zhou, J, Li, Z & Dutkiewicz, E 2006, 'Improving mobile station energy efficiency in IEEE 802.16e WMAN by burst scheduling', GLOBECOM - IEEE Global Telecommunications Conference.View/Download from: Publisher's site
In this paper, we tackle the packet scheduling problem in IEEE 802.16e Wireless Metropolitan Area Network (WMAN), where the Sleep Mode is applied to save energy of Mobile Stations (MSs). Our objective is to design an energy efficient scheduling policy which works closely with the Sleep Mode mechanism so as to maximize battery lifetime in MSs. To the best of our knowledge no power saving scheduling algorithms based on Sleep Mode defined in IEEE 802.16e have been proposed so far in the literature. We propose a Longest Virtual Burst First (LVBF) scheduling algorithm which schedules packets of MSs in a virtual burst mode where there is one primary MS and multiple secondary MSs sharing the wireless link resource. LVBF prolongs MSs' lifetime by reducing the average time when MSs stay in the idle state and the number of state transitions between the awake and sleep states. Simulation results show that, in comparison with the round robin scheduling scheme, LVBF can produce significant overall energy saving, while guaranteeing the QoS requirements of MSs in terms of their minimum data rates. © 2006 IEEE.
Sun, Y, Fang, G & Shi, J 2006, 'Research on the implementation of VoIP service in mobile Ad-hoc network', Proceedings of the 1st IEEE International Conference on Wireless Broadband and Ultra Wideband Communications, AusWireless 2006, pp. 77-83.
Traditional way to implement VoIP application on hard-wired network is based on the fixed and invariable IP addresses of the source and destination nodes. However, in Mobile Ad-hoc Network (MANET), the IP address of each node is auto-configured and may change at any time. Therefore, the traditional way cannot be applied on MANET. This paper presents a new way to design VoIP application on Mobile Ad-hoc Network, which can correctly solve the problem of variable IP addresses in MANET and make the nodes communicate with each other reliably.