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In this paper, we propose new joint transport and MAC protocols for ad hoc wireless networks based on an optimization framework. To overcome the practical and efficiency limitations of previous research, we develop a different framework based on independent sets and propose an implementable heuristic algorithm. We address the implementation issues of the proposed algorithm. Simulation results confirm the efficiency and fairness of our protocols.
Jing WU Jeonghoon MO Richard J. LA
We study the interaction of TCP and the proportional fair scheduling algorithm in wireless networks. We show that the additive increase and multiplicative decrease algorithm of TCP can favor bad channel users, which results in inefficient use of radio resources. To remedy the problem, a proportional queue management scheme is proposed. The effectiveness of the algorithm is shown by simulations.
Tran Minh TRUNG Jeonghoon MO Seong-Lyun KIM
In this paper, we propose simple but effective modifications of 802.11 MAC (media access control) to resolve efficiency and fairness issues, in wireless ad-hoc networks [2]. Our proposal, based on the flow concept, incorporated faster end-to-end forwarding by assigning higher priority to a node that has packets to relay than others. After completion of end-to-end transmission, the node will be assigned a lower priority level to yield to other nodes. Simulation results show that the proposed scheme (F-MAC) significantly enhances the throughput of ad-hoc networks, while keeping fair sharing of bandwidth among mobile nodes.
Hongkyu JEONG JungYul CHOI Jeonghoon MO Minho KANG
Optical Burst Switching (OBS) is one of the most promising switching technologies for next generation optical networks. As delay-sensitive applications such as Voice-over-IP (VoIP) have recently become popular, OBS networks should guarantee stringent Quality of Service (QoS) requirements for such applications. Thus, this paper proposes an Adaptive Loss-aware Flow Control (ALFC) scheme, which adaptively decides on the burst offset time based on loss-rate information delivered from core nodes for assigning a high priority to delay-sensitive application traffic. The proposed ALFC scheme also controls the upper-bounds of the factors inducing delay and jitter for guaranteeing the delay and jitter requirements of delay-sensitive application traffic. Moreover, a piggybacking method used in the proposed scheme accelerates the guarantee of the loss, delay, and jitter requirements because the response time for flow control can be extremely reduced up to a quarter of the Round Trip Time (RTT) on average while minimizing the signaling overhead. Simulation results show that our mechanism can guarantee a 10-3 loss-rate under any traffic load while offering satisfactory levels of delay and jitter for delay-sensitive applications.