Beeshanga received BEng in Telecommunications Engineering (Hons I) and PhD in Electronic Engineering (Wireless Communications) degrees from Macquarie University, Sydney, Australia, in 2011 and 2015 respectively.
Following his PhD he held a Research Associate position in the Department of Engineering at Macquarie University. He is currently a Lecturer in the School of Computing and Communications, University of Technology Sydney.
He has close ongoing industry relationships with Intel Labs and CSIRO. He has over 4 years of experience working on 802.11 and cellular networks. His research interests are resource allocation in wireless networks, cognitive radio, compressed sensing and cross-layer techniques.
Additionally he has over 5 years of experience in teaching multiple Electronic and Telecommunications Engineering subjects at Macquarie University and Sydney Institute of Business and Technology.
Beeshanga is the recipient of Macquarie University Medal in Engineering and Vice-Chancellor’s Commendation for Academic Excellence.
Can supervise: YES
- Resource allocation in wireless networks
- Cognitive radio networks
- Spectrum sensing
- Compressed sensing
- Cross-layer techniques
- Radio environment maps
Spectrum Access System (SAS) Spectrum Sharing With Fine-grained Protection/Exclusion Zone Differentiation.
Patent status: US provisional patent application filed (2018) - Reg. No. 71,803.
An Access Node Controller, an Apparatus for an Access Node, an Access Node for a Mobile Communication System, a Mobile Communication System, a Method and Computer Program for an Access Node.
Patent status: US patent application filed (2017) - US15/638,491.
Allocating Wireless Channels.
Patent status: US patent application filed (2017) - US15/474,606.
Methods and Devices for Shared Spectrum Allocation.
Patent status: International (PCT) patent application filed (2016) - P86319DE/P86319PCT.
Methods and Devices for User Detection in Spectrum Sharing.
Patent status: US patent application filed (2016) - P97272.
SAS PAL GAA Co-channel Interference Mitigation.
Patent status: US provisional patent application filed (2016) - P98713Z.
Uplink Interference Management in Shared Spectrum Networks.
Patent status: US patent application filed (2015) - P86405.
Methods for Performing Mobile Communications Mobile Terminal Devices, Base Stations, and Network Control Devices.
Patent status: International (PCT) patent application filed (2015) - P86127DE/P86127PCT.
Communication Device and Method for Communicating using a Frequency Range.
Patent status: US patent application filed (2015) - P83877.
- Signal Buffering for Licensed Shared Access, US9491634, Nov. 2016.
© 1997-2012 IEEE. Generating Rayleigh fading is a well investigated subject. However, most existing methods are fundamentally based on a sum-of-sinusoids, hence have a high computational complexity and become impractical when modelling massive MIMO systems. In this letter we present a novel recursive complex number multiplication method to generate Rayleigh fading for discrete signals. The computational complexity of the method is 75-94% less than all prominent sum-of-sinusoid methods. It also preserves the theoretically expected Bessel autocorrelation of a fading channel, zero cross-correlation between different fading channels and the power spectral density.
Abeywickrama, HV, He, Y, Dutkiewicz, E, Jayawickrama, BA & Mueck, M 2020, 'A Reinforcement Learning Approach for Fair User Coverage Using UAV Mounted Base Stations Under Energy Constraints', IEEE Open Journal of Vehicular Technology, vol. 1, pp. 67-81.View/Download from: Publisher's site
Basnet, S, He, Y, Dutkiewicz, E & Jayawickrama, BA 2019, 'Resource Allocation in Moving and Fixed General Authorized Access Users in Spectrum Access System', IEEE Access, vol. 7, pp. 107863-107873.View/Download from: Publisher's site
© 2013 IEEE. Spectrum access system (SAS) is a spectrum sharing framework proposed to share the spectrum between the incumbent users and the citizen broadband radio service devices, i.e. Priority access users and general authorized access (GAA) users. In this paper, we propose an interfering angle based method for the joint resource (channel and transmit power) allocation problem to the mobile and fixed GAA users. With mobile GAA users, the set of GAA users that can hear each other will change at different time instants making the resource allocation problem more challenging. The resource allocation of fixed and mobile GAA users is done considering coexistence with priority users, as well as coexistence between mobile and fixed GAA users. For the conflict-free resource allocation to fixed and mobile GAA users, we propose to use the maximum allowed transmit power for the beams of fixed GAA users that lie within the interference range of mobile GAA users. The simulation results show improved capacity from our proposed method while satisfying a predetermined interference constraint.
Sutton, GJ, Zeng, J, Liu, RP, Ni, W, Nguyen, DN, Jayawickrama, BA, Huang, X, Abolhasan, M, Zhang, Z, Dutkiewicz, E & Lv, T 2019, 'Enabling Technologies for Ultra-Reliable and Low Latency Communications: From PHY and MAC Layer Perspectives', IEEE Communications Surveys & Tutorials, vol. 21, no. 3, pp. 2488-2524.View/Download from: Publisher's site
Future 5th generation networks are expected to enable three key services-enhanced mobile broadband, massive machine type communications and ultra-reliable and low latency communications (URLLC). As per the 3rd generation partnership project URLLC requirements, it is expected that the reliability of one transmission of a 32 byte packet will be at least 99.999% and the latency will be at most 1 ms. This unprecedented level of reliability and latency will yield various new applications, such as smart grids, industrial automation and intelligent transport systems. In this survey we present potential future URLLC applications, and summarize the corresponding reliability and latency requirements. We provide a comprehensive discussion on physical (PHY) and medium access control (MAC) layer techniques that enable URLLC, addressing both licensed and unlicensed bands. This paper evaluates the relevant PHY and MAC techniques for their ability to improve the reliability and reduce the latency. We identify that enabling long-term evolution to coexist in the unlicensed spectrum is also a potential enabler of URLLC in the unlicensed band, and provide numerical evaluations. Lastly, this paper discusses the potential future research directions and challenges in achieving the URLLC requirements.
Abeywickrama, HV, Jayawickrama, BA, He, Y & Dutkiewicz, E 2018, 'Comprehensive energy consumption model for unmanned aerial vehicles, based on empirical studies of battery performance', IEEE Access, vol. 6, pp. 58383-58394.View/Download from: Publisher's site
© 2018 IEEE. Unmanned aerial vehicles (UAVs) are fast gaining popularity in a wide variety of areas and are already being used for a range of tasks. Despite their many desirable features, a number of drawbacks hinder the potential of UAV applications. As typical UAVs are powered by on-board batteries, limited battery lifetime is identified as a key limitation in UAV applications. Thus, in order to preserve the available energy, planning UAV missions in an energy efficient manner is of utmost importance. For energy efficient UAV mission planning, it is necessary to predict the energy consumption of specific UAV manoeuvring actions. Accurate energy prediction requires a reliable and realistic energy consumption model. In this paper, we present a consistent and complete energy consumption model for UAVs based on empirical studies of battery usage for various UAV activities. We considered the impact of different flight scenarios and conditions on UAV energy consumption when developing the proposed model. The energy consumption model presented in this paper can be readily used for energy efficient UAV mission planning.
He, Y, Jayawickrama, BA, Dutkiewicz, E, Srikanteswara, S & Mueck, M 2018, 'Priority Access and General Authorized Access Interference Mitigation in the Spectrum Access System', IEEE Transactions on Vehicular Technology, vol. 67, no. 6, pp. 4969-4983.View/Download from: Publisher's site
© 1967-2012 IEEE. To meet the capacity needs of next generation wireless communications, the U.S. Federal Communications Commission has recently introduced the spectrum access system. Spectrum is shared between three tiers - incumbents, priority access licensees (PAL), and general authorized access (GAA) licensees. When the incumbents are absent, PAL and GAA share the spectrum under the constraint that GAA ensure the interference to PAL is no more than $-$40 dBm with at least 99% confidence. We consider the scenario where locations are not shared between PAL and GAA. We propose a PAL-GAA cochannel interference mitigation technique that does not expose base station locations. Our approach relies on GAA sharing the distribution and maximum number of transmitters in a finite area. We show how PAL can derive the distribution of the aggregate interference using the probability density function and characteristic function, and notify GAA about the exclusion zones in space that will guarantee that the interference requirement is met. We also propose a numerical approximation using inverse fast Fourier and discrete Fourier transforms. Analytically calculated distribution aligns well with the numerical results. Additionally, we formulate an optimization problem for the optimal exclusion zone size. We analytically prove convexity of the problem. Our approach reduces the exclusion zone size by over 42%, which gives significantly more spectral opportunities to GAA in the spatial domain.
Jayawickrama, BA, He, Y, Dutkiewicz, E & Mueck, MD 2018, 'Scalable Spectrum Access System for Massive Machine Type Communication', IEEE NETWORK, vol. 32, no. 3, pp. 154-160.View/Download from: Publisher's site
Sutton, G, Zeng, J, Liu, R, Ni, W, Nguyen, D, Jayawickrama, B, Huang, X, Abolhasan, M & Zhang, Z 2018, 'Enabling Ultra-Reliable and Low Latency Communications through Unlicensed Spectrum', IEEE Network, vol. 32, no. 2, pp. 70-77.View/Download from: Publisher's site
In this article, we aim to address the question of how to exploit the unlicensed spectrum to achieve URLLC. Potential URLLC PHY mechanisms are reviewed and then compared via simulations to demonstrate their potential benefits to URLLC. Although a number of important PHY techniques help with URLLC, the PHY layer exhibits an intrinsic trade-off between latency and reliability, posed by limited and unstable wireless channels. We then explore MAC mechanisms and discuss multi-channel strategies for achieving low-latency LTE unlicensed band access. We demonstrate, via simulations, that the periods without access to the unlicensed band can be substantially reduced by maintaining channel access processes on multiple unlicensed channels, choosing the channels intelligently, and implementing RTS/CTS.
Jayawickrama, BA, Dutkiewicz, E, Mueck, M & He, Y 2016, 'On the Usage of Geolocation Aware Spectrum Measurements for Incumbent Location and Transmit Power Detection', IEEE Transactions on Vehicular Technology, vol. 65, no. 10, pp. 8177-8189.View/Download from: Publisher's site
Determining the geographical area that needs to be excluded due to incumbent activity is critical to realize high spectral utilization in spectrum sharing networks. This can be achieved by estimating the incumbent location and transmit power. However, keeping the hardware complexity of sensing nodes to a minimum and scalability are critical for spectrum sharing applications with commercial intent. We present a discrete-space l1-norm minimization solution based on geolocation-aware energy detection measurements. In practice, the accuracy of geolocation tagging is limited. We capture the impact as a basis mismatch and derive the necessary condition that needs to be satisfied for successful detection of multiple incumbents' location and transmit power. We find the upper bound for the probability of eliminating the impact of limited geolocation tagging accuracy in a lognormal shadow fading environment, which is applicable to all generic I1-norm minimization techniques. We propose an algorithm based on orthogonal matching pursuit that decreases the residual in each iteration by allowing a selected set of basis vectors to rotate in a controlled manner. Numerical evaluation of the proposed algorithm in a Licensed Shared Access (LSA) network shows a significant improvement in the probability of missed detection and false alarm.
Abeywickrama, HV, He, Y, Dutkiewicz, E & Jayawickrama, BA 2019, 'An Adaptive UAV Network for Increased User Coverage and Spectral Efficiency', IEEE Wireless Communications and Networking Conference, WCNC, IEEE Wireless Communications and Networking Conference, IEEE, Marrakesh, Morocco.View/Download from: Publisher's site
© 2019 IEEE. Unmanned Aerial Vehicles (UAVs) are fast becoming a popular choice in a variety of applications in wireless communication systems. UAV-mounted base stations (UAV-BSs) are an effective and cost-efficient solution for providing wireless connectivity where fixed infrastructure is not available or destroyed. We present a method of using UAV-BSs to provide coverage to mobile users in a fixed area. We propose an algorithm for predicting the user locations based on their mobility data and clustering the predicted locations, so that one UAV-BS would provide coverage to one user cluster. The proposed method, hence is similar to the UAV-BSs following the users to keep them under the coverage region. Simulation results show that the proposed method increases the user coverage by 47%-72% and increases the spectral efficiency by 43%-55% depending on the scenario and in addition, reduces the number of UAV-BSs required to provide coverage.
Abeywickrama, HV, Jayawickrama, BA, He, Y & Dutkiewicz, E 2018, 'Empirical Power Consumption Model for UAVs', 2018 IEEE 88th Vehicular Technology Conference (VTC-Fall), IEEE Vehicular Technology Conference, IEEE, Chicago, IL, USA, USA, pp. 1-5.View/Download from: Publisher's site
Unmanned Aerial Vehicles (UAV) are gaining popularity in a range of areas and are already being used for a wide variety of purposes. While UAVs have many desirable features, limited battery lifetime is identified as a key restriction in UAV applications. Typical UAVs being electric devices, powered by on-board batteries, this constrain has limited their capabilities to a considerable extent. Thus planning UAV missions in an energy efficient manner is of utmost importance. To achieve this, for prediction of power consumption, it is necessary to have a reliable power consumption model. In this paper, we present a consistent and complete power consumption model for UAVs based on empirical studies of battery usage for various UAV activities. The power consumption model presented in this paper can be readily used for energy efficient UAV mission planning.
Basnet, S, Jayawickrama, BA, He, Y & Dutkiewicz, E 2018, 'Fairness Aware Resource Allocation for Average Capacity Maximisation in General Authorized Access User', 2018 IEEE 88th Vehicular Technology Conference (VTC-Fall), IEEE Vehicular Technology Conference, IEEE, Chicago, IL, USA, USA, pp. 1-5.View/Download from: Publisher's site
Spectrum Access System (SAS) is a three-tier spectrum sharing framework proposed for 3.5 GHz by Federal Communication Commission (FCC) in the United States. General Authorized Access (GAA) users in SAS do not have an assigned channel and can opportunistically access the Priority Access Licensee (PAL) channel satisfying the interference constraint proposed by FCC. Coexistence among GAA users in SAS is a key problem to be solved to enhance the system capacity to meet the increasing traffic demand. In this work, we propose a method for fair and efficient spectrum utilisation for GAA users. To achieve the fairness among GAA users equal interference budget allocation scheme is proposed for each set of GAA users that can hear each other. Our proposed method decide the optimal channel switching schedule that maximises the average capacity of GAA users while satisfying the interference constraint at PAL protection area. This work jointly considers the fairness between GAA users and the average capacity maximisation of GAA network. Simulation result justifies the performance of our proposed method for average capacity maximisation of GAA users and fairness between GAA users by comparing with existing works.
Basnet, S, Jayawickrama, BA, He, Y & Dutkiewicz, E 2018, 'Transmit Power Allocation for General Authorized Access in Spectrum Access System Using Carrier Sensing Range', IEEE Vehicular Technology Conference, IEEE Vehicular Technology Conference, IEEE, Chicago, IL, USA, USA, pp. 1-5.View/Download from: Publisher's site
The optimal use of spectrum is a key focus for all regulatory bodies. Federal Communications Commission has introduced Spectrum Access System (SAS) to maximise the spectrum utilisation in the US 3.5 GHz band. SAS is a three-tier spectrum sharing framework where Citizen Broadband Radio Service (CBRS) devices can access the channel when it is not used by Incumbent Access users. CBRS consists of Priority Access Licensee (PAL) and General Authorized Access (GAA). In this paper, we consider the problem of optimum transmit power allocation for GAA users using a carrier sensing range i.e. maximum distance a user can be sensed while guaranteeing the interference to PAL from GAA users is below the threshold. We use carrier sensing range to find the sets of GAA users that cannot transmit at the same time and adjust the interference budget of transmitting GAA users. We present an algorithm for transmit power allocation for GAA users in the SAS. The proposed algorithm uses the transmission characteristics and location information provided by Citizen Broadband Radio Service Devices to SAS to maximise the peak capacity of GAA users ensuring the interference constraint to PAL. Simulation results show that the proposed algorithm significantly increases the peak capacity of GAA users by considering the carrier sensing range and adjusted interference budget.
He, Y, Jayawickrama, BA & Dutkiewicz, E 2019, 'Distributed Power Allocation Algorithm for General Authorised Access in Spectrum Access System', IEEE Wireless Communications and Networking Conference, WCNC, IEEE Wireless Communications and Networking Conference, IEEE, Marrakesh, Morocco.View/Download from: Publisher's site
© 2019 IEEE. To meet the capacity needs of the next generation wireless communications, U.S. Federal Communications Commission has recently introduced Spectrum Access System. Spectrum is shared between three tiers - Incumbents, Priority Access Licensees (PAL) and General Authorised Access (GAA) Licensees. When the incumbents are absent, PAL and GAA share the spectrum under the constraint that GAA ensure the aggregate interference to PAL is no more than -80 dBm within the PAL protection area. Currently GAA users are required to report their geolocations. However, geolocation is private information that GAA may not be willing to share. We propose a distributed GAA power allocation algorithm that does not require centralised coordination on sharing locations with other GAA users via SAS. We analytically proved the critical point of the interference along the PAL protection area to avoid calculating the interference on every points of the area. We proposed exclusion zone, transitional zone and open zone for GAA users to calculate the self-determined transmit power. Simulation results show that our method meets the interference requirement and achieve more than 90% of capacity approximation to the optimal centralised method, while completely masking the GAA locations.
Suarez-Rodriguez, C, He, Y, Jayawickrama, BA & Dutkiewicz, E 2019, 'Low-Overhead Handover-Skipping Technique for 5G Networks', IEEE Wireless Communications and Networking Conference, WCNC.View/Download from: Publisher's site
© 2019 IEEE. Network densification has been one of the principal causes of performance gain in cellular networks, and 5G networks will not be any different. As cell sizes shrink, handovers become more frequent incurring extra delays that bury all the prospective gains. Mobility in multi-tier dense cellular networks calls for a change in the way it has been traditionally handled in an always-on world, where users take universal data access for granted. Invisible to them, mobile network operators need to provision backhauling to include advanced interference mitigation techniques. In this paper, we propose a spectrum database-aided handover management technique that aims to mitigate the number of disconnections without overloading the backhaul unnecessarily. The proposed technique exploits a spectrum database that stores reception information along with geolocation data, commercially available on any handheld device. Moreover, we have benchmarked several state-of-the-art handover schemes for 5G networks against ours in a realistic urban environment with user mobility trace data. The results highlight that our method can deliver the same downstream traffic with 33% decrease in disconnections when compared to the conventional approach. At the same time, backhaul traffic is reduced up to 68% against our counterparts.
Suarez-Rodriguez, C, Jayawickrama, BA, He, Y, Bader, F & Heimlich, M 2017, 'Performance analysis of REM-based handover algorithm for multi-tier cellular networks', IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC, Annual International Symposium on Personal, Indoor, and Mobile Radio Communications, IEEE, Montreal, QC, Canada, pp. 1-6.View/Download from: Publisher's site
© 2017 IEEE. The advent of 5G networks, where a plethora of spectrum-sharing schemes are expected to be adopted as an answer to the ever-growing users' need for data traffic, will require addressing mobility ubiquitously. The trend initiated with the deployment of heterogeneous networks and past standards will give way to a multi-tiered network where different services will coexist, such as device-to-device, vehicle-to-vehicle or massive-machine communications. Because of the high variability in the cell sizes given the different transmit powers, the classical handover process, which relies solely on measurements, will lead to an unbearable network overhead as a consequence of the high number of handovers. The use of spatial databases, also known as radio environment maps (REM), was first introduced as a tool to detect opportunistic spectrum access opportunities in cognitive radio applications. Since then, REM usage has been widely expanded to cover deployment optimization, interference management or resource allocation to name a few. In this paper, we introduce a handover algorithm that can predict the best network connection for the current user's trajectory from a radio environment map. We consider a geometric approach to derive the handover and handover-failure regions and compare the current handover algorithm used in Long-Term Evolution with our proposed one. Results show a drastic reduction in the number of handovers while maintaining a trade-off between the ping-pong handover and the handover-failure probabilities.
Abeywickrama, HV, Jayawickrama, BA, He, Y & Dutkiewicz, E 2018, 'Potential field based inter-UAV collision avoidance using virtual target relocation', 2018 IEEE 87th Vehicular Technology Conference (VTC Spring), IEEE Vehicular Technology Conference, IEEE, Porto, Portugal, pp. 1-5.View/Download from: Publisher's site
© 2018 IEEE. Unmanned Aerial Vehicles (UAV) are becoming popular in a range of areas. This has given rise to the concept of UAV swarms, where multiple UAVs act together to achieve a common task. With multiple UAVs flying in close proximity to each other, sharing the same airspace, the risk of inter-UAV collisions increases. It's important to avoid these collisions while having minimal impact on the UAV system. We propose a novel Potential Field Method (PFM) based algorithm for inter-UAV collision avoidance which considerably reduces the total time taken by the UAV system to achieve its goal. We control the collision avoidance actions of the UAVs by virtually relocating their targets. The positions of the virtual targets are calculated to minimize the collision probability, based on a probability function we introduced. The proposed algorithm reduces the total system time approximately by 20\% as opposed to the traditional PFM.
Suarez-Rodriguez, C, Jayawickrama, BA, Bader, F, Dutkiewicz, E & Heimlich, M 2018, 'REM-based handover algorithm for next-generation multi-tier cellular networks', IEEE Wireless Communications and Networking Conference, WCNC, IEEE Wireless Communications and Networking Conference, IEEE, Barcelona, Spain, pp. 1-6.View/Download from: Publisher's site
© 2018 IEEE. The strongest-cell criterion has been extensively used for handover algorithms during the last cellular-network generations. When network topologies become multi-layered, it results in abrupt behaviors such as the ping-pong effect as a consequence of the power gap between tiers and their irregular deployment. This effect not only affects users' quality of experience but also introduces a significant network overhead. Therefore, we propose an original handover algorithm based on predicted incomplete channel states from a Radio Environment Map to reduce this effect. The proposed algorithm is user triggered, network assisted, and fully backward compatible with LTE-A. Moreover, we evaluate the performance of our proposed algorithm against LTE-A in a two-tier cellular network for different user speeds following the guidelines outlined by the 3GPP on diverse matters (channel, mobility, wrapping, etc.). When applying realistic timing, our results reveal a highly substantial improvement in the number of ping-pong handovers regardless of the handover policy adopted in comparison to LTE-A without sacrificing users' experience; for instance, we obtain at least an order of magnitude decrease in the ping-pong rate at the expense of losing less than 9 percent in spectral efficiency.
Abeywickrama, HV, Jayawickrama, BA, He, Y & Dutkiewicz, E 2017, 'Algorithm for Energy Efficient Inter-UAV Collision Avoidance', 2017 17th International Symposium on Communications and Information Technologies (ISCIT), International Symposium on Communications and Information Technologies, IEEE, Cairns, Australia.View/Download from: Publisher's site
Basnet, S, Jayawickrama, BA, He, Y & Dutkiewicz, E 2017, 'Considering switching overhead for transmit power allocation for GAA in spectrum access system', Proceedings of the 2017 17th International Symposium on Communications and Information Technologies, ISCIT 2017, International Symposium on Communications and Information Technologies, IEEE, Cairns, QLD, Australia, pp. 1-5.View/Download from: Publisher's site
© 2017 IEEE. To enable spectrum sharing the Federal Communication Commission (FCC) has proposed the Spectrum Access System (SAS). In SAS General Authorised Access (GAA) can opportunistically access any part of the 3.5 GHz band. In SAS prior information regarding the time usage of spectrum is not provided by Priority Access Licensee (PAL) and when PAL operation starts the GAA needs to ensure they do not cause interference above a predetermined threshold. In this work we propose a method for GAA Citizen Broadband Radio Service Devices (CBSDs) to switch to different channel considering the probability of spectrum utilisation of GAA. Switching overhead is the time delay when switching the channel from one to another. In our work we proposed the method to calculate switching overhead and maximised average sum capacity of GAA CBSDs considering switching overhead and Root Mean Square (RMS) interference at PAL protection area. Simulations result shows that average sum capacity of GAA CBSDs can be maximised using the proposed method.
Basnet, S, Jayawickrama, BA, He, Y, Dutkiewicz, E & Mueck, MD 2017, 'Opportunistic Access to PAL Channel for Multi-RAT GAA Transmission in Spectrum Access System', IEEE Vehicular Technology Conference, IEEE Vehicular Technology Conference, IEEE, Sydney, NSW, Australia, pp. 1-5.View/Download from: Publisher's site
© 2017 IEEE. Spectrum Access System (SAS) is a three tier spectrum sharing framework proposed by the FCC. In this framework the aggregate interference of tier-3 General Authorised Access (GAA) users should be below a predetermined threshold anywhere within the tier-2 Priority Access Licensee (PAL) exclusion zone. GAA are expected to use a diverse range of Radio Access Technologies (RATs) with different levels of loading. We propose an optimal transmit power and probability of spectrum utilisation allocation scheme for GAA users that meets the average aggregate interference constraint within the GAA network. Most of the capacity maximisation studies consider the instantaneous aggregated interference from secondary users. In this paper we present an average aggregated interference method to optimise the capacity of GAA users in a single channel. Simulation results suggest that we can significantly increase the capacity of the channel by considering the probability spectrum utilisation of GAA users.
Dutkiewicz, E, He, Y, Jayawickrama, BA & Abeywickrama, HV 2017, 'Radio Environment Maps Generation and Spectrum Sensing Testbed for Spectrum Sharing in 5G Networks', PROCEEDINGS OF THE 2017 IEEE-APS TOPICAL CONFERENCE ON ANTENNAS AND PROPAGATION IN WIRELESS COMMUNICATIONS (APWC), IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications (APWC), IEEE, Verona, ITALY, pp. 33-36.
Dutkiewicz, E, Jayawickrama, BA & He, Y 2017, 'Radio spectrum maps for emerging IoT and 5G networks: Applications to smart buildings', ICECOS 2017 - Proceeding of 2017 International Conference on Electrical Engineering and Computer Science: Sustaining the Cultural Heritage Toward the Smart Environment for Better Future, International Conference on Electrical Engineering and Computer Science, IEEE, Palembang, Indonesia, pp. 7-9.View/Download from: Publisher's site
© 2017 IEEE. The high demand for wireless Internet including emerging Internet of Things (IoT) applications is putting extreme pressure on better utilisation of the available radio spectrum. The expected spectrum 'crunch' requires highly efficient radio resource management schemes with low complexity and high responsiveness to the changing network conditions. Spectrum sharing is regarded as an essential approach to regaining access to otherwise unused spectrum and it is considered an essential component in the development of IoT and 5G networks. Spectrum sharing can be conducted at different time scales. As the time scale of the operation of spectrum sharing decreases, the possibility for utilising more available spectrum holes increases. However, the shorter time scale brings with it challenges. Efficient decisions regarding the use of spectrum sharing require accurate knowledge of the spatial and temporal spectrum use in a geographical area of interest. This knowledge can be represented in Radio Spectrum Maps which need to be generated efficiently and accurately. In this paper we give an overview of the spectrum sharing concept for IoT and 5G networks. We also present our research on spectrum sharing to enable Smart Building IoT applications.
Wang, H, Dutkiewicz, E, Jayawickrama, BA & Mueck, MD 2017, 'Design of Contour Based Protection Zones for Sublicensing in Spectrum Access Systems', IEEE Vehicular Technology Conference, IEEE Vehicular Technology Conference, IEEE, Sydney, NSW, Australia, pp. 1-5.View/Download from: Publisher's site
© 2017 IEEE. Spectrum Access System (SAS) allows incumbent military systems to share spectrum in a hierarchical manner with tier-2 Priority Access License (PAL) users and tier-3 General Authorized Access (GAA) users. FCC has recently allowed PAL owners to sublicense their channels. Therefore, when GAA channels are congested they can request a sublicense to access the PAL channel on a coordinated basis, which provides interference protection from other GAA users. In this paper, we propose a grid map to measure and monitor the secondary spectrum market for the purpose of spectrum trading with QoS guarantee. This work provides the subsequent spectrum trading models with a reasonable and dedicated interference graph for further optimization of spectrum allocation. Compared with traditional longterm spectrum licensing policy, short-term licensing makes the spectrum allocated effectively. We find the optimal resolution of the discrete grid map that maximizes the profit from sublicensing. Simulation results are provided to demonstrate how fine to grid the region and let the PAL owner achieve monetary benefit, in a given number of sensors.
Wang, H, Dutkiewicz, E, Jayawickrama, BA & Mueck, MD 2017, 'Detection of contour boundary for sublicensing in spectrum access systems', 2017 17th International Symposium on Communications and Information Technologies, ISCIT 2017, International Symposium on Communications and Information Technologies, IEEE, Cairns, QLD, Australia, pp. 1-5.View/Download from: Publisher's site
© 2017 IEEE. Associated to database and a local centralized system, the short-term spectrum sublicensing is one of the potential approaches to improve the spectrum efficiency in the 5G networks. If the sublicences are assigned to the heterogeneous base stations that are from different operators, the interference issue becomes challenging to tackle. In this paper, we propose a solution of contour boundary detection for sublicensing to coordinate the interference among heterogeneous base stations in the space domain. As the direct access points to sever the end users, the base stations know and even could predict the traffic requirements over their coverage areas. Therefore, we enable individual base station as a sublicensee based on self-reported protection contour and optimize the best allocation for the system to guarantee the interference-free operations among those who spatially use the same sublicense simultaneously. Considering the selfish behaviours of base stations, we employ the sensor networks to monitor and measure their contours. Then we estimate the contour boundary by detecting the inner and outer contour boundary. Finally we compare the estimation accuracies of different sensor networks and demonstrate an interference-free allocation for the sublicensees.
Jayawickrama, BA, Dutkiewicz, E & Mueck, M 2015, 'Incumbent User Active Area Detection for Licensed Shared Access', Proceedings of the 2015 IEEE 82nd Vehicular Technology Conference (VTC Fall), IEEE Vehicular Technology Conference, IEEE, Boston, USA, pp. 1-5.View/Download from: Publisher's site
Print Request Permissions Licensed Shared Access is a European standardisation effort which promotes repository based quasi-static hierarchical spectrum sharing. In this scheme the sharing time base is in the order of months if not years. For widespread use of Licensed Shared Access, shrinking the sharing time base is crucial. In this paper we propose a scheme to reduce the sharing time base to seconds or minutes scale. We present a new technique named lightweight Radio Environment Map based on a Kalman Filter derived from geo-location aware spectrum measurements, which can be run at the shared access licensee end. Our objective is to determine the active area of a static or slowly moving incumbent. We consider a challenging scenario where a large fraction of measurements is missing and the available measurements are highly distorted. Performance of our incumbent active area detection approach is evaluated by simulating a low power incumbent in an urban cellular environment. Simulation results show a substantial improvement of missed detection area in comparison to the counterpart that does not use our lightweight Radio Environment Map.
Jayawickrama, BA, Dutkiewicz, E, Oppermann, I & Mueck, M 2014, 'Iteratively Reweighted Compressive Sensing Based Algorithm for Spectrum Cartography in Cognitive Radio Networks', 2014 IEEE Wireless Communications and Networking Conference (WCNC), IEEE Wireless Communications and Networking Conference, IEEE, Istanbul, Turkey.View/Download from: Publisher's site
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.
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.
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
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