Ni, W, Abolhasan, M, Hagelstein, B, Liu, RP & Wang, X 2017, 'A New Trellis Model for MAC Layer Cooperative Retransmission Protocols', IEEE Transactions on Vehicular Technology, vol. 66, no. 4, pp. 3448-3461.View/Download from: Publisher's site
Hagelstein, B, Abolhasan, M, Franklin, D, Ni, W & Safaei, F 2016, 'Analytic Performance Model for State-Based MAC Layer Cooperative Retransmission Protocols', IEEE Transactions on Mobile Computing, vol. 15, no. 1, pp. 32-44.View/Download from: Publisher's site
COOPERATIVE retransmission is a well-established technique
for improving wireless network capacity . Its
effectiveness is strongly dependent on the choice of relay
selection algorithm, as this determines both the probability
of retransmission success and the probability of collisions
between simultaneous retransmission attempts. Consequently,
relay selection algorithm design remains an open
area of research.
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: 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.
Hagelstein, B, Abolhasan, M, Franklin, DR & Safaei, F 2013, 'Improving Fairness in IEEE 802.11 Networks Using MAC Layer Opportunistic Retransmission', Computer Networks, vol. 57, no. 17, pp. 3410-3427.View/Download from: Publisher's site
This paper introduces DAFMAC (Decode And Forward MAC), a scalable opportunistic cooperative retransmission enhancement for the IEEE 802.11 MAC protocol which operates without the need for additional explicit control signalling. Distributed opportunistic retransmission algorithms rely on selecting a single suitable relay without direct arbitration between nodes. Simulations show that DAFMAC offers a significant improvement in fairness for both throughput and jitter, giving multiple parallel data flows a more equal opportunity to utilise the channel. DAFMAC cooperative retransmissions are shown to reduce node energy consumption for a given throughput. Further, the DAFMAC relay selection algorithm is shown to scale very well in terms of complexity and memory requirements in comparison to other cooperative retransmission schemes.
Hagelstein, B, Abolhasan, M, Franklin, DR & Safaei, F 2013, 'A General Performance Model for MAC Layer Cooperative Retransmission Contention Protocols', GLOBECOM, IEEE Global Telecommunications Conference, IEEE, Atlanta, USA, pp. 1584-1589.View/Download from: Publisher's site
Cooperative retransmission schemes can significantly improve transmission reliability and performance over high loss and time-varying links. However, analytically comparing performance between retransmission strategies is challenging and generally requires simplistic assumptions. This paper presents a general model for the performance of distributed, slot-based contention algorithms for opportunistic decode and forward retransmission algorithms. The model is independent of specific modulation or coding schemes and may be adapted to suit statebased transmission probability models. The model is validated through QualNet simulations.
Cooper, C, Hagelstein, B & Franklin, DR 2012, 'Implementation of Opportunistic Cooperative Diversity in an Ad-Hoc Network using Commodity Hardware', Wireless Communications and Mobile Computing Conference (IWCMC), 2012 8th International, ACM International Wireless Communications and Mobile Computing Conference, IEEE, Limassol, Cyprus, pp. 165-168.View/Download from: Publisher's site
Hagelstein, B, Abolhasan, M, Franklin, DR & Safaei, F 2010, 'An Efficient Opportunistic Cooperative Diversity Protocol for IEEE 802.11 Networks', Proceedings of the 6th International Wireless Communications and Mobile Computing Conference, International Wireless Communications and Mobile Computing Conference, ACM, Caen, France, pp. 417-421.View/Download from: Publisher's site
Opportunistic cooperation promises to enhance the user experience when streaming media over wireless devices by improving wireless network reliability at the link level. This paper presents DAFMAC, an efficient cooperative diversity partner selection algorithm for IEEE 802.11 devices. Simulation results show DAFMAC provides a significantly higher transmission reliability in poor channel conditions than traditional ARQ techniques without modifying the device hardware. Further analysis shows the low overhead of DAFMAC makes it highly competitive with other proposed cooperative retransmission mechanisms in an ad-hoc network.
Wang, JC, Hagelstein, B & Abolhasan, M 2010, 'Experimental Evaluation of IEEE 802.11s Path Selection Protocols in a Mesh Testbed', 2010 4th International Conference on Signal Processing and Communication Systems - Proceedings, International Conference on Signal Processing and Communication Systems, IEEE, Gold Coast, Australia, pp. 1-3.View/Download from: Publisher's site
IEEE 802.11s is an upcoming standard that defines how wireless devices can interconnect in a multi-hop configuration. While there are several protocol stacks based on the IEEE 802.11s draft standard, there has not been a formal study or comparison examining their practical performance. This paper evaluates the routing performance of open80211s in a real-world mesh testbed. The experiments benchmark open80211s against two established network layer routing protocols - OLSR and B.A.T.M.A.N.. The experimental results show that open80211s does not outperform existing routing protocols in practice. This indicates that more design and development effort is required for IEEE 802.11s to yield the performance that is expected for an IEEE standard protocol.
Abolhasan, M & Hagelstein, B 2013, 'Real-world performance of current proactive multi-hop mesh protocols', Real-world performance of current proactive multi-hop mesh protocols, IEEE APCC Wireless Communication Systems (IEEE APCC), Shanghai, Shanghai, China, pp. 44-47.View/Download from: Publisher's site
The proliferation of mesh or ad hoc network protocols has lead to a push for protocol standardisation. While there are a number of both open-source and proprietary mesh routing protocols being developed, there is only a small amount of literature available that shows relative strengths and weaknesses of different protocols. This paper investigates the performance of a number of available routing protocols using a real-world testbed. Three routing protocols - optimised link state routing (OLSR), better approach to mobile ad hoc network (B.A.T.M.A.N.) and BABEL - were chosen for this study. Our investigations focus on the multi-hopping performance and the ability of each routing protocol to recover from link failures. Our results show that B.A.T.M.A.N. and BABEL outperform OLSR both in terms of multi-hopping performance and in route re-discovery latency.
Abolhasan, M, Hagelstein, B & Franklin, DR 2008, 'Development and Performance Evaluation of a Flexible, Low Cost MANET', 2nd International Conference on Signal Processing and Communication Systems 2008. ICSPCS 2008., ICSOCS 2008, IEEE, Gold coast, Australia, pp. 1-6.View/Download from: Publisher's site
Performance evaluations of multi-hop ad hoc network routing protocols have been primarily conducted through analytic and simulation-based studies, which frequently fail to accurately predict real-world performance and behaviour. One reason for this is the challenge in developing low cost, representative test beds with the degree of flexibility and mobility required. We have developed a portable wireless ad hoc node (PWAN) device which establishes multi-hop routes using the OLSR routing protocol. The PWAN's performance has been investigated using two test bed configurations to evaluate its capacity under conditions of high node density in a short-range, multi-hop environment. Our results illustrate that such networks are capable of providing high quality connections when traffic density is low. However, the network link quality deteriorates dramatically as the traffic level increases, and the network topology becomes unstable until the traffic level is reduced.
Abolhasan, M, Hagelstein, B, Wang, JC-P, Franklin, DR, Safaei, F & Wysocki, T 2008, 'Development and Performance Evaluation of a Flexible, Low Cost MANET', ICSPCS: 2ND INTERNATIONAL CONFERENCE ON SIGNAL PROCESSING AND COMMUNICATION SYSTEMS, PROCEEDINGS, 2nd International Conference on Signal Processing and Communication Systems, IEEE, Gold Coast, AUSTRALIA, pp. 107-+.