Dr Justin Lipman is an Industry Associate Professor at the University of Technology Sydney and Director of the RF Communications Technologies (RFCT) Lab, where he leads industry engagement in RF technologies, Internet of Things, Tactile Internet, Software Defined Communication and Agriculture 4.0. He serves as committee member in Standards Australia contributing to International IoT standards and is a Research Program Lead for the Food Agility Cooperative Research Center. He received his PhD Telecommunications and BE Computer Engineering from the University of Wollongong, Australia in 2003 and 1999 respectively. From 2004 to 2017, Dr. Lipman was based in Shanghai, China and held a number of senior management and technical leadership roles at Intel and Alcatel leading research and innovation, product architecture and IP generation. He is an IEEE Senior Member. His research interests are in all “things” adaptive, connected, distributed and ubiquitous.
- Sr. Member IEEE
- Standards Australia IoT
Can supervise: YES
- Tactile Internet / Internet of Things / Cyber Physical Systems
- Wireless Communication (Mesh, Sensor Networks)
- Drones / Biomimicry
- Intelligent Agents
- Indoor/Outdoor Localization
- Embedded systems
- Software Defined Networking
- Python Rapid Prototyping
- Tactile Internet / IoT
Amiri, M, Tofigh, F, Shariati, N, Lipman, J & Abolhasan, M 2019, 'Miniature tri-wideband Sierpinski-Minkowski fractals metamaterial perfect absorber', IET MICROWAVES ANTENNAS & PROPAGATION, vol. 13, no. 7, pp. 991-996.View/Download from: Publisher's site
Khan, AA, Abolhasan, M, Ni, W, Lipman, J & Jamalipour, A 2019, 'A Hybrid-Fuzzy Logic Guided Genetic Algorithm (H-FLGA) Approach for Resource Optimization in 5G VANETs', IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY, vol. 68, no. 7, pp. 6964-6974.View/Download from: UTS OPUS or Publisher's site
Makhdoom, I, Abolhasan, M, Lipman, J, Liu, RP & Ni, W 2019, 'Anatomy of Threats to The Internet of Things', Communications Surveys and Tutorials, IEEE Communications Society, vol. 21, no. 2, pp. 1636-1675.View/Download from: UTS OPUS or Publisher's site
The world is resorting to the Internet of Things (IoT) for ease of control and monitoring of smart devices. The ubiquitous use of IoT ranges from industrial control systems (ICS) to e-Health, e-Commerce, smart cities, supply chain management, smart cars, cyber physical systems (CPS), and a lot more. Such reliance on IoT is resulting in a significant amount of data to be generated, collected, processed, and analyzed. The big data analytics is no doubt beneficial for business development. However, at the same time, numerous threats to the availability and privacy of the user data, message, and device integrity, the vulnerability of IoT devices to malware attacks and the risk of physical compromise of devices pose a significant danger to the sustenance of IoT. This paper thus endeavors to highlight most of the known threats at various layers of the IoT architecture with a focus on the anatomy of malware attacks. We present a detailed attack methodology adopted by some of the most successful malware attacks on IoT, including ICS and CPS. We also deduce an attack strategy of a distributed denial of service attack through IoT botnet followed by requisite security measures. In the end, we propose a composite guideline for the development of an IoT security framework based on industry best practices and also highlight lessons learned, pitfalls and some open research challenges.
Abolhasan, M, Abdollahi, M, Ni, W, Jamalipour, A, Shariati, N & Lipman, J 2018, 'A Routing Framework for Offloading Traffic from Cellular Networks to SDN-based Multi-Hop Device-to-Device Networks', IEEE Transactions on Network and Service Management, vol. 15, no. 4, pp. 1516-1531.View/Download from: UTS OPUS or Publisher's site
IEEE Device-to-Device (D2D) Communications are set to form an integral part of future 5G wireless networks. D2D communications have a number of benefits such as improving energy efficiency and spectrum utilization. Until now much of the D2D research in LTE and 5G-type network scenarios have focused on direct (one-hop) communications between two adjacent mobile devices. In this paper, we propose a new routing framework called Virtual Ad hoc Routing Protocol (VARP). This framework introduces significant advantages such as better security, lower routing overheads, and higher scalability, when compared to conventional ad hoc routing protocols. It also reduces traffic overhead in LTE networks using multi-hop D2D communications under management of a SDN-controller. Further, it enables the development of various types of routing protocols for different networking scenarios. To this end, a source-routing based protocol was developed on top of VARP, referred to as VARP-S. We present a detailed analytical study of routing overhead in the VARP-S protocol, as compared to overhead analysis of our previous proposed Hybrid SDN Architecture for wireless distributed networks (HSAW)IEEENetworkMehran. Our results show that VARP-S, compared to HSAW, achieves higher network scalability and lower power consumption for mobile nodes.
Abolhasan, M, lipman, J, Ni, W & Hagelstein, B 2015, 'Software-Defined Wireless Networking: Centralised, Distributed, or Hybrid?', IEEE Network: the magazine of global information exchange, vol. 29, no. 4, pp. 32-38.View/Download from: UTS OPUS or Publisher's site
Scalability is a key issue in large scale WDNs, such as vehicular networks and device-to-device networks. To address the issue, this article extends the SDN concept, and presents a new network architecture that eliminates the need of multi-hop flooding for route discovery, thereby enabling WDNs to scale. The key idea of the new architecture is to split network control and data forwarding by using two separate frequency bands. Another important aspect of the architecture is that computational complexity of routing is split between the SDN controller and the forwarding nodes, thereby allowing nodes to make distributed routing decisions. As a result, network control of the new architecture has a hybrid structure, which improves the operability and scalability of large scale WDNs. Our case study shows that the new architecture is able to substantially improve scalability and reliability of WDNs, especially in mobile environments.
Ni, W, Abolhasan, M, Collings, I, Lipman, J, Wang, X & Tao, M 2015, 'Graph Theory and Its Applications to Future Network Planning: Software-Defined Online Small Cell Management', IEEE Wireless Communications Magazine, vol. 22, no. 1, pp. 52-60.View/Download from: UTS OPUS or Publisher's site
Network planning is facing new and critical challenges due to ad hoc deployment, unbalanced and drastically varying traffic demands, as well as limited backhaul and hardware resources in emerging small cell architectures. We discuss the application of graph theory to address the challenges. A clique-based software-defined online network management approach is proposed that captures traffic imbalance and fluctuation of small cells and optimally plans frequencies, infrastructures, and network structure at any instant. Its applications to three important small cell scenarios of cloud radio, point-to-point microwave backhaul, and interoperator spectrum sharing are demonstrated. Comparison studies show that in each of the scenarios, this new approach is able to significantly outperform conventional static offline network planning schemes in terms of throughput and satisfaction levels of small cells with regard to allocated bandwidths. Specifically, the throughput can be improved by 155 percent for the cloud radio scenario and 110.95 percent for the microwave backhaul scenario. The satisfaction level can be improved by 40 percent for interoperator spectrum sharing.
Movassaghigilani, S, Abolhasan, M, Smith, DB, Lipman, J & Jamalipour, A 2014, 'Wireless Body Area Networks: A Survey', IEEE Communication Surveys and Tutorials, vol. 16, no. Third Quarter 2014, pp. 1658-1686.View/Download from: UTS OPUS or Publisher's site
AlAamri, H, Abolhasan, M, Franklin, DR & Lipman, J 2013, 'Optimised relay selection for route discovery in reactive routing', Ad Hoc Networks, vol. 11, no. 1, pp. 70-88.View/Download from: UTS OPUS or Publisher's site
On-demand routing protocols have the potential to provide scalable information delivery in large ad hoc networks. The novelty of these protocols is in their approach to route discovery, where a route is determined only when it is required by initiating a route discovery procedure. Much of the research in this area has focused on reducing the route discovery overhead when prior knowledge of the destination is available at the source or by routing through stable links. Hence, many of the protocols proposed to date still resort to flooding the network when prior knowledge about the destination is un-available. This paper proposes a novel routing protocol for ad hoc networks, called On-demand Tree-based Routing Protocol (OTRP). This protocol combines the idea of hop-by-hop routing (as used by AODV) with an efficient route discovery algorithm called Tree-based Optimised Flooding (TOF) to improve scalability of ad hoc networks when there is no prior knowledge about the destination. To achieve this in OTRP, route discovery overheads are minimised by selectively flooding the network through a limited set of nodes, referred to as branching nodes. The key factors governing the performance of OTRP are theoretically analysed and evaluated, including the number of branch nodes, location of branching nodes and number of Route REQuest (RREQ) retries. It was found that the performance of OTRP (evaluated using a variety of well-known metrics) improves as the number of branching nodes increases and the number of consumed RREQ retries is reduced. Additionally, theoretical analysis and simulation results shows that OTRP outperforms AODV. DYMO, and OLSR with reduced overheads as the number of nodes and traffic load increases.
Movassaghigilani, S, Abolhasan, M & Lipman, J 2013, 'A Review of Routing Protocols in Wireless Body Area Networks', Journal of Networks, vol. 8, no. 3, pp. 559-575.View/Download from: UTS OPUS or Publisher's site
Recent technological advancements in wireless communication, integrated circuits and Micro-Electro- Mechanical Systems (MEMs) has enabled miniaturized, low-power, intelligent, invasive/ non-invasive micro and nanotechnology sensor nodes placed in or on the human body for use in monitoring body function and its immediate environment referred to as Body Area Networks (BANs). BANs face many stringent requirements in terms of delay, power, temperature and network lifetime which need to be taken into serious consideration in the design of different protocols. Since routing protocols play an important role in the overall system performance in terms of delay, power consumption, temperature and so on, a thorough study on existing routing protocols in BANs is necessary. Also, the specific challenges of BANs necessitates the design of new routing protocols specifically designed for BANs. This paper provides a survey of existing routing protocols mainly proposed for BANs. These protocols are further classified into five main categories namely, temperature based, cross-layer, cluster based, cost-effective and QoS-based routing, where each protocol is described under its specified category. Also, comparison among routing protocols in each category is given.
Movassaghigilani, S, Abolhasan, M & Lipman, J 2011, 'Addressing Schemes for Body Area Networks', IEEE Communications Letters, vol. 15, no. 12, pp. 1310-1313.View/Download from: UTS OPUS or Publisher's site
This letter explores address allocation in Body Area Networks (BANs) and proposes two novel schemes - Optimized Prophet Address Allocation (OPAA) and Hierarchical Collisionfree Address Protocol (HCAP). The aim of the schemes is to use fewer bits in the address space, solve address wastage problems, reduce collisions and improve power efficiency. The usability and efficiency of the proposed schemes is shown through simulation and analysis.
Abolhasan, M, Wysocki, T & Lipman, J 2005, 'A New Strategy to Improve Proactive Route Updates in Mobile Ad Hoc Networks', EURASIP Journal on Wireless Communications and Networking, vol. 2005, no. 5, pp. 828-837.View/Download from: UTS OPUS
This paper presents two new route update strategies for performing proactive route discovery in mobile ad hoc networks (MANETs). The first strategy is referred to as minimum displacement update routing (MDUR). In this strategy, the rate at which route updates are sent into the network is controlled by how often a node changes its location by a required distance. The second strategy is called minimum topology change update (MTCU). In this strategy, the route updating rate is proportional to the level of topology change each node experiences. We implemented MDUR and MTCU on top of the fisheye state routing (FSR) protocol and investigated their performance by simulation. The simulations were performed in a number of different scenarios, with varied network mobility, density, traffic, and boundary. Our results indicate that both MDUR and MTCU produce significantly lower levels of control overhead than FSR and achieve higher levels of throughput as the density and the level of traffic in the network are increased.
Lipman, J, Abolhasan, M, Boustead, P & Chicharo, JF 2005, 'An optimised resource aware approach to information collection in ad hoc networks', Ad Hoc Networks, vol. 3, no. 5, pp. 643-655.View/Download from: UTS OPUS
In ad hoc networks there is a need for all-to-one protocols that allow for information collection or âsensingâ of the state of an ad hoc network and the nodes that comprise it. Such protocols may be used for service discovery, auto-configuration, network management, topology discovery or reliable flooding. There is a parallel between this type of sensing in ad hoc networks and that of sensor networks. However, ad hoc networks and sensor networks differ in their application, construction, characteristics and constraints. The main priority of sensor networks is for the flow of data from sensors back to a sink, but in an ad hoc network this may be of secondary importance. Hence, protocols suitable to sensor networks are not necessarily suitable to ad hoc networks and vice versa. We propose, Resource Aware Information Collection (RAIC), a distributed two phased resource aware approach to information collection in ad hoc networks. RAIC utilises a resource aware optimised flooding mechanism to both disseminate requests and initialise a backbone of resource suitable nodes responsible for relaying replies back to the node collecting information. RAIC in the process of collecting information from all nodes in an ad hoc network is shown to consume less energy and introduce less overhead compared with Directed Diffusion and a brute force approach. Importantly, over multiple successive queries (in an energy constrained environment), the use of resource awareness allows for the load of relaying to be distributed to those nodes most suitable, thereby extending the lifetime of the network.
Lipman, J, Boustead, P & Judge, J 2003, 'Neighbor aware adaptive power flooding (NAAP) in mobile ad hoc networks', International Journal of Foundations of Computer Science, vol. 14, no. 2, pp. 237-252.View/Download from: Publisher's site
This paper introduces Neighbor Aware Adaptive Power flooding, an optimized flooding mechanism used in mobile ad hoc networks (MANETS) that employs several mechanisms (neighbor coverage, power control, neighbor awareness and local optimization) to limit the broadcast storm problem, reduce duplicate packet reception and lower power consumption in both transmission and reception. Upon receiving an optimized broadcast, a relay determines a new set of possible relays (to continue the flood) based upon local neighbor information and the previous optimized broadcast. Additionally, neighboring relays only consider the shared neighbors they are closest to. A relay may perform local optimization (to reduce power consumption and isolate broadcasts) by substituting one high power broadcast with two or more low power broadcasts, thereby introducing additional hops, We show that compared to blind flooding and multipoint relaying, NAAP in a static environment greatly reduces the problems associated with the broadcast storm problem, duplicate packet reception and power consumption. © 2003 World Scientific Publishing Company.
Abdollahi, M, Abolhasan, M, Shariati, N, Lipman, J, Jamalipour, A & Ni, W 2019, 'A Routing Protocol for SDN-based Multi-hop D2D Communications', 2019 16th IEEE Annual Consumer Communications and Networking Conference, CCNC 2019, EEE Annual Consumer Communications & Networking Conference, IEEE, USA, pp. 895-898.View/Download from: UTS OPUS or Publisher's site
© 2019 IEEE. This paper presents a new Multi-hop Device-to-Device (MD2D) routing protocol, referred to as SMDRP (SDN-based Multi-hop D2D Routing Protocol), for SDN-based wireless networks. Our proposed protocol can be considered as a semi-distributed routing protocol, where an SDN controller manages and controls part of the overall MD2D routing functionality to increase scalability while enabling network operators to control and maintain the out-of-band packet forwarding network. This paper also extends prior work on the Hybrid SDN Architecture for Wireless Distributed Networks (HSAW)  and is adapted to the framework presented in this paper. In HSAW, since all link state information is flooded by the controller to the nodes, the network will experience scalability problem. In our approach, this problem is overcome by only passing the next hop for each active route to the mobile nodes. To investigate this, we performed a theoretical and simulation studies comparing HSAW with SMDRP. From our result, it can be seen that for larger density populated networks, SMDRP shows better scalability than HSAW. In addition, mobile nodes need less memory and energy for their communications.
Ashtari, S, Tofigh, F, Abolhasan, M, Lipman, J & Ni, W 2019, 'Efficient Cellular Base Stations Sleep Mode Control Using Image Matching', 2019 IEEE 89TH VEHICULAR TECHNOLOGY CONFERENCE (VTC2019-SPRING), 89th IEEE Vehicular Technology Conference (VTC Spring), IEEE, Kuala Lumpur, MALAYSIA.
Chemalamarri, VD, Braun, R, Lipman, J & Abolhasan, M 2018, 'A Multi-agent Controller to enable Cognition in Software Defined Networks', 2018 28th International Telecommunication Networks and Applications Conference (ITNAC), International Telecommunication Networks and Applications Conference, IEEE, Sydney, Australia, pp. 52-56.View/Download from: UTS OPUS or Publisher's site
Current SDN controllers are not cognitive. We propose a new architecture for an SDN controller to enable intelligence. The proposed new architecture is based on Multi-agent systems. As a prototype, we have built a MAS-SDN controller using the GOAL agent programming language. We highlight the motivation behind the new architecture, describe the architecture and provide some initial results
Saki, M, Abolhasan, M & Lipman, J 2019, 'A big sensor data offloading scheme in rail networks', IEEE Vehicular Technology Conference, IEEE Vehicular Technology Conference, IEEE, Kuala Lumpur, Malaysia, Malaysia.View/Download from: UTS OPUS or Publisher's site
© 2019 IEEE. In this paper, we propose an offloading scheme to transfer massive stored sensor data from rolling stock to railway data centers. We apply a delayed offloading strategy for non-critical stored data assuming that the critical data has been already separated through an appropriate edge processing task and has been sent via a real-time communication such as cellular networks. We propose train stations as potential and feasible spots for data offloading via available wireless local area networks (WLAN) such as existing WiFi network at stations. Thus, stations will not only be the places of passenger exchange but also data exchange. We develop an analytical model customized for the proposed offloading strategy in rail applications. Then we validate the performance of our model through simulation in various scenarios in Omnet. The simulation results shows an accuracy of %98.67 for the proposed analytical model with reference to the simulation results in Omnetpp. Additionally, by using our proposed scheme, we can theoretically offload up to 5.43 GB per each stopping station.
Tofigh, F, Mao, G, Lipman, J & Abolhasan, M 2018, 'Crowd Density Mapping Based on Wi-Fi Measurements on Train Platforms', 2018 12TH INTERNATIONAL CONFERENCE ON SIGNAL PROCESSING AND COMMUNICATION SYSTEMS (ICSPCS), International Conference on Signal Processing and Communication Systems, IEEE, Cairns, Australia.View/Download from: UTS OPUS or Publisher's site
Crowd distribution is a challenging issue in the management and design levels. This paper provides a passive method to derive the crowd density distribution using Wi-Fi measurements on a real scenario. Six WiFi access points (AP) are deployed in the platform 2/3 of Redfern station, Sydney to monitor the platform for a week. Based on the probability maps that are built using RSSI measurements and prior knowledge, the crowd distribution is calculated on the platform and its results are compared with distributions acquired from CCTV images. Final density heat maps are in good agreement with the acquired results from CCTV cameras.
Gamal, M, Abolhasan, M, Lipman, J, Liu, RP & Ni, W 2018, 'Multi Objective Resource Optimisation for Network Function Virtualisation Requests', 2018 26TH INTERNATIONAL CONFERENCE ON SYSTEMS ENGINEERING (ICSENG 2018), 26th International Conference on Systems Engineering (ICSEng), IEEE, Univ Technol Sydney, Sydney, AUSTRALIA.View/Download from: UTS OPUS
Movassaghigilani, S, Abolhasan, M & Lipman, J 2012, 'Energy Efficient Thermal and Power Aware (ETPA) Routing in Body Area Networks', 2012 IEEE 23rd International Symposium on Personal, Indoor and Mobile Radio Communications - (PIMRC), IEEE International Symposium on Personal and Indoor Mobile Radio Conference, IEEE, Sydney, pp. 1130-1135.View/Download from: UTS OPUS or Publisher's site
Research on routing in a network of intelligent, lightweight, micro and nano-technology sensors deployed in or around the body, namely Body Area Network (BAN), has gained great interest in the recent years. In this paper, we present an energy efficient, thermal and power aware routing algorithm for BANs named Energy Efficient Thermal and Power Aware routing (ETPA). ETPA considers a nodeâs temperature, energy level and received power from adjacent nodes in the cost function calculation. An optimization problem is also defined in order to minimize average temperature rise in the network. Our analysis demonstrates that ETPA can significantly decrease temperature rise and power consumption as well as providing a more efficient usage of the available resources compared to the most efficient routing protocol proposed so far in BANs, namely PRPLC. Also, ETPA has a considerably higher depletion time that guarantees a longer lasting communication among nodes.
Movassaghigilani, S, Abolhasan, M & Lipman, J 2011, 'Hierarchical Collision-free Addressing Protocol(HCAP) for Body Area Networks', The Third International Workshop on Wireless Sensor, Actuator and Robot Networks(WiSARN) :INFOCOM 2011-Workshops, IEEE Conference on Computer Communications, IEEE, Shanghai, China, pp. 543-548.View/Download from: UTS OPUS or Publisher's site
In Body Area Networks (BANs) the addressing scheme used to address nodes is fundamental to the effective operation of a BAN. This paper proposes a novel BAN addressing scheme called Hierarchical Collision-free Addressing Protocol (HCAP). Proposed scheme is collision free, reduces power consumption and tackles the address wastage problem. Two important scenarios (random location and fixed location) are defined and studied. Through a series of simulation results we show the efficiency and usability of the proposed scheme in Body Area Networks.
Movassaghigilani, S, Abolhasan, M & Lipman, J 2011, 'Optimized Prophet Address Allocation (OPAA) for Body Area Networks', Proceedings of the 7th International Wireless Communications and Mobile Computing Conference (IEEE IWCMC 2011), ACM International Wireless Communications and Mobile Computing Conference, IEEE, Istanbul, Turkey, pp. 2098-2102.View/Download from: UTS OPUS or Publisher's site
Each node in a Body Area Network (BAN) needs to be assigned with a free IP address before it may participate in any sort of communication. This paper evaluates the performance of an IP address allocation scheme, namely Prophet allocation to be used for BANs. This allocation scheme is a fully decentralized addressing scheme which is applicable to BANs as it provides low latency, low communication overhead and low complexity. Relative theoretical analysis and simulation experiments have also been conducted to demonstrate its benefits which also represent the reason for the choice of this allocation scheme. It also solves the issues related to network partition and merger efficiently.
Amri, HA & Abolhasan, M 2010, 'On Optimising Route Discovery for Multi-interface and Power-Aware Nodes in Heterogeneous MANETs', On Optimising Route Discovery for Multi-interface and Power-Aware Nodes in Heterogeneous MANETs, ICWMC 2010, The Sixth International Conference on Wireless and Mobile Communications (ICWMC 2010), Valencia, pp. 244-249.View/Download from: UTS OPUS or Publisher's site
This paper presents a new routing discovery strategy for heterogeneous MANETs. Node heterogeneity is modeled in terms of: types and number of different interfaces, power, and transmission ranges. Our proposed route discovery algorithm is implemented on the top of On-demand Tree-based Routing Protocol (OTRP) and hence it is called OTRP Heterogeneity-Aware (OTRP_HA). OTRP_HA utilizes node heterogeneity and optimizes route discovery to reduce overheads and ensures connectivities between different types of nodes with different interfaces. Each node makes its own decision to participate in the route discovery process according to its location, local density, and available resources. Simulation results show that OTRP_HA outperforms OTRP and AODV and it reduces overheads as a number of nodes and traffic increase, while it also further prolongs the lifetime of battery-powered single-interface nodes when compared to AODV.
Wang, JC, Abolhasan, M, Franklin, DR, Safaei, F & Lipman, J 2007, 'On Separating Route Control and Data Flows in Multi-Radio Multi-Hop Ad Hoc Network', Proceedings of the 200715th IEEE International Conference on Networks, IEEE International Conference on Networks, IEEE, Adelaide, Australia, pp. 19-24.View/Download from: UTS OPUS or Publisher's site
Ad hoc networks typically require a significant amount of routing and control information to be distributed in a timely and reliable manner throughout the network, particularly in dynamic environments. As traffic levels increase and the network becomes more heavily congested, there is an increased probability that these critical packets are lost, resulting in obsolete control information being used to make important decisions. This would further compound the problem of network congestion and lead to a very rapid loss of connectivity and throughput. Given this, we argue the solutions to these problems should not rely on putting extra bandwidth on a radio interface. Instead, we should exploit the use of multiple radios to ensure the route can be firmly established. In this paper, we propose a multiradio solution which reserves one radio channel exclusively for routing. Our simulation results have demonstrated that using a separate radio for routing protocol would dramatically improve reliability in heavily loaded ad hoc wireless networks, thereby effectively alleviating the impact of network congestion.
Abolhasan, M & Lipman, J 2006, 'Self-selection route discovery strategies for reactive routing in ad hoc networks', Self-selection route discovery strategies for reactive routing in ad hoc networks, InterSense '06, ACM, Nice, France.View/Download from: UTS OPUS or Publisher's site
Routing in Ad hoc Networks has received a significant amount of attention. In recent years, the focus of research has been in on-demand (or reactive) routing protocols due to the recognition that these protocols have the potential to achieve higher levels of scalability than proactive routing strategies. However, most on-demand routing protocols proposed to date attempt to increase routing efficiency by using existing knowledge about the destination or by increasing the stability of the routes. Little research has been done to reduce route discovery overhead when no previous destination information is available. We present a number of different strategies, which encourage a more distributed and localised approach to route discovery by allowing each intermediate node during route discovery to make forwarding decisions using localised knowledge and self-selection. The use of self-selection for route discovery enables nodes to independently make route request (RREQ) forwarding decisions based upon a selection criterion or by satisfying certain conditions. The nodes which do not satisfy the selection criterion do not rebroadcast the RREQs. This provides a more effective and efficient search strategy than the use of traditional brute force blind flooding. We implemented our self-selecting route discovery strategies over AODV using the GloMoSim network simulation package, and compared the performance with existing routing protocols. Our simulation results show that a significant drop in the number of control packets can be achieved by giving each intermediate node more authority for self-selection during route discovery. Furthermore, a significant increase in routing performance is achieved as the number of nodes in the network is increased.
Wang, JCP, ElGindy, H & Lipman, J 2006, 'On cache prefetching strategies for integrated infostation-cellular network', Proceedings - Conference on Local Computer Networks, LCN, pp. 185-192.View/Download from: Publisher's site
Infostations provide an inexpensive and high speed wireless disseminator that features discontinuous coverage by bounding many low cost, limited transmission range and high-bandwidth local wireless stations over an extended terrain. In this paper, we provide a system model in which several infostations are placed within the coverage area of a low bandwidth wide-area cellular network to form an Integrated Infostation-Cellular Network (HCN). In this model, the infostation continuously broadcasts data to its clients, while cellular network provides information to clients via explicit requests from clients. Based on this new model, we proposed a prefetching scheme that is capable of selectively prefetching information at client's local storage. From experimental results, the proposed model and technique show a reduction in number of requests made via expensive cellular network, thereby alleviating cost of wireless data access. Moreover, since the number of requests is reduced, the load on the cellular system is reduced. Further the cost of wireless data access is significantly reduced from both client and server perspectives. © 2006 IEEE.
Abolhasan, M & Lipman, J 2005, 'Efficient and Highly Scalable Route Discovey for On-demand Routing Protocols in Ad hoc Networks', Efficient and Highly Scalable Route Discovey for On-demand Routing Protocols in Ad hoc Networks, Local Computer Networks, 2005. 30th Anniversary. The IEEE Conference on, IEEE, Sydney, Australia, pp. 358-366.View/Download from: UTS OPUS or Publisher's site
This paper presents a number of different route discovery strategies for on-demand routing protocols, which provide more control to each intermediate node make during the route discovery phase to make intelligent forwarding decisions. This is achieved through the idea of self-selection. In self-selecting route discovery each node independently makes route request (RREQ) forwarding decisions based upon a selection criterion or by satisfying certain conditions. The nodes which do not satisfy the selection criterion do not rebroadcast the routing packets. We implemented our self-selecting route discovery strategies over AODV using the GloMoSim network simulation package, and compared the performance with existing route discovery strategies used in AODV. Our simulation results show that a significant drop in the number of control packets can be achieved by giving each intermediate node more authority for self-selection during route discovery. Furthermore, a significant increase in throughput is achieved as the number nodes in the network is increased
Abolhasan, M, Wysocki, T & Lipman, J 2005, 'Performance Investigation on three-classes of MANET Routing Protocols', Performance Investigation on three-classes of MANET Routing Protocols, Communications, 2005 Asia-Pacific Conference on, Communications, 2005 Asia-Pacific Conference on, Perth, WA, pp. 774-778.View/Download from: UTS OPUS or Publisher's site
Routing in ad hoc networks has received significant attention with a number of different routing protocols proposed in recent years. These routing protocols may be classified into three main categories: proactive, reactive and hybrid. Prior work aimed at comparing the performance of routing protocols has mainly focused on comparing reactive and proactive protocols. In this paper, we present a simulation study of different routing protocols from all three categories. We also explore the benefits and performance of each routing category. Further, we present a discussion of future research directions for routing in ad hoc networks
Liu, BH, Chou, CT, Lipman, J & Jha, S 2005, 'Using frequency division to reduce MAI in DS-CDMA wireless sensor networks', IEEE Wireless Communications and Networking Conference, WCNC, pp. 657-663.View/Download from: Publisher's site
The performance of Direct Sequence Code Division Multiple Access (DS-CDMA) sensor networks is limited by Multiple Access Interference (MAI). This paper proposes using frequency division to reduce the MAI in a DS-CDMA sensor network. We provide theoretical characterization of the mean MAI at a given node and show that a small number of frequency channels can reduce the MAI significantly. In addition, we provide a comparison of our proposed system to systems which do not use frequency division or which employ contention based protocols. Our study found that, by using only a small number of frequency channels, our system has less channel contention, lower packet latency, higher packet delivery ratio and lower energy consumption. © 2005 IEEE.
Abolhasan, M & Lipman, J 2004, 'A routing strategy for heterogeneous mobile ad hoc networks', Emerging Technologies: Frontiers of Mobile and Wireless Communication, 2004. Proceedings of the IEEE 6th Circuits and Systems Symposium on (Volume:1 ), Emerging Technologies: Frontiers of Mobile and Wireless Communication, 2004., In the 5th IEEE International Conference on Wireless Communications, Networking and Mobile Computing, Shanghai, Shanghai, China, pp. 13-16.View/Download from: UTS OPUS or Publisher's site
This paper presents a new routing strategy for heterogeneous mobile ad hoc networks. We refer to this strategy as on-demand utility-based routing protocol (OUBRP). This protocol introduces a utility-based route discovery strategy, which aims to minimise the number of control packets disseminated into the network during route discovery by efficiently using available resources at each node. Furthermore, we propose a new strategy to eliminate uni-directional links during the route discovery phase. We refer to this strategy as uni-directional link elimination (ULE). We performed a simulation study to compare the performance of OUBRP with a number of different routing protocols proposed for MANETs. Our results show that OUBRP compared to other routing strategies produces significantly fewer control packets and achieves higher levels of successful packet delivery with increasing number of nodes. Furthermore, we propose a number of alternative uni-directional link elimination strategies.
Lipman, J, Boustead, P & Chicharo, J 2004, 'Reliable optimised flooding in Ad hoc networks', Proceedings of the IEEE 6th Circuits and Systems Symposium on Emerging Technologies: Frontiers of Mobile and Wireless Communication, pp. 521-524.
Information dissemination (flooding) forms an integral part of routing protocols, network management, service discovery and information collection (sensing). Given the broadcast nature of ad hoc network communications, information dissemination provides a challenging problem. Blind flooding in ad hoc networks results in the broadcast storm problem. To limit the broadcast storm problem, mechanisms for optimised flooding have been proposed. However, this optimisation reduces the inherent level of redundancy. We propose to apply the Minimum Spanning Tree (MST) algorithm using local one hop topology in a distributed manner as the basis of a more reliable optimised flooding mechanism called, Reliable Minimum Spanning Tree (RMST) flood. RMST utilises unique properties of MST graphs that allow for broadcast transmissions to be replaced by unicast transmissions. Unicast transmission is inherently more reliable than broadcast transmission as it utilises link layer acknowledgement and retransmission, thereby improving the reliability of a flood and reducing the broadcast storm problem. We show through simulation that RMST is able to achieve equivalent reliability in terms of packet delivery compared to Blind flooding. Importantly, RMST is able to achieve significantly better performance than MPR and equivalent performance to LMSTFlood in terms of reducing the broadcast storm problem.
Lipman, J, Boustead, P, Chicharo, J & Judge, J 2003, 'Resource aware information dissemination in ad hoc networks', IEEE International Conference on Networks, ICON, pp. 591-596.
Information dissemination (flooding) forms an integral part of routing protocols, network management, service discovery and information collection (sensing). Given the broadcast nature of ad hoc network communications, information dissemination provides a challenging problem. This paper in troduces Utility Based Flooding (UBF). UBF is a distributed optimised flooding mechanism for ad hoc networks that unlike existing optimised flooding algorithms is fully resource aware. Resource awareness is achieved by assigning a forwarding utility to neighouring nodes to determining the desirability of a neighbouring node in continuing a flood. UBF is particularly applicable to ad hoc network environments composed of heterogeneous nodes that may have varying characteristics and constraints. In this paper, UBF is compared to existing flooding mechanisms in a constrained environment. Nodes are assigned varying degrees of remaining battery power and user based constraints that limit a nodes benevolence based upon its remaining battery power. We show through simulation that UBF compared to Utility Based Multipoint Relay (UMPR) flooding, Multipoint Relay (MPR) flooding and Blind flooding significantly improves broadcast reachability over successive broadcasts, does not adversely affect performance and extends the lifetime of the network. UBF delivers packets to over 90% of nodes in the network for over 70 successive broadcasts. Blind flooding, UMPR and MPR are only able achieve 42, 39 and 23 successive broadcasts respectively. ©2003 IEEE.