Issue No. 05 - May (2008 vol. 7)
Token passing medium access control (MAC) protocols are gaining interest amongst wireless ad hoc network researchers as they provide unrivalled advantages over the existing IEEE 802.11 standards. This paper introduces a hybrid Token-CDMA MAC protocol that is based on a token passing scheme with the incorporation of code division multiple access (CDMA). With its unique CDMA feature, the proposed MAC is able to support multiple, simultaneous transmissions. The proposed protocol provides both Quality of Service (QoS) and high network resource utilization, while ensuring the stability of the network. This paper examines the performance of the proposed MAC scheme by simulation, and compares its performance against that of other MAC protocols that have appeared in the literature. Simulation results demonstrate that our proposed MAC scheme is effective in decreasing the packet delay and significantly shortens the length of the queue. The input traffic model used in the simulation is a two-state Markov Modulated Poisson Process (MMPP). The data rate QoS is enforced by implementing a modified leaky bucket mechanism in the proposed MAC scheme. The simulation also takes into account channel link errors caused by the wireless link by implementing a multi-layered Gilbert-Elliot model.
Distributed networks, Wireless communication, Algorithm/protocol design and analysis
I. Liu, F. Takawira and H. Xu, "A Hybrid Token-CDMA MAC Protocol for Wireless Ad Hoc Networks," in IEEE Transactions on Mobile Computing, vol. 7, no. , pp. 557-569, 2007.