Channel allocation was extensively investigated in the framework of cellular networks, but it was rarely studied in the wireless ad-hoc networks, especially in the multi-hop ad-hoc networks. In this paper, we study the competitive multi-radio channel allocation problem in multi-hop wireless networks in detail. We model the channel allocation problem as a static cooperative game, in which some players collaborate to achieve high date rate. We propose the min-max coalition-proof Nash equilibrium (MMCPNE) channel allocation scheme in the game, which aims to max the achieved date rates of communication links. We analyze the existence of MMCPNE and prove the necessary conditions for MMCPNE. Furthermore, we propose several algorithms that enable the selfish players to converge to MMCPNE. Simulation results show that MMCPNE outperforms CPNE and NE schemes in terms of achieved data rates of the multi-hop links due to cooperation gain.

Performance of TCP-Vegas is not satisfactory in multihop ad hoc networks over IEEE 802.11 MAC protocol. We analyze the problem with a unified network model and a TCP source window model. We observe that Vegas cannot maintain the optimal window with maximum average throughput when the network capacity is smaller than the reset slow start threshold of Vegas. The aggregate throughput of all traffics decreases as the load of network increases. The main reasons lie in Vegas’s large minimum congestion window, large reset slow start threshold and aggressive window increase policy. All of them induce overload of the network, which cause packet losses at MAC layer and over-reaction at routing layer. These in return result in the breakup of end-to-end connections and reduce the throughput. To fix these problems, we propose a modified TCP protocol based on TCP-Vegas for multihop ad hoc networks, called Vegas-W. We extend congestion window to fraction with a rate control timer under the TCP sending process. Probing mechanisms of legacy TCP-Vegas in both slow start and congestion avoidance phases are changed to increase congestion window after receiving more than one ACK. Furthermore, we update slow start threshold by tracking stable window. We evaluate the performance of Vegas-W through ns-2. Extensive simulation results show that Vegas-W can improve the throughput up to 87% over legacy TCP-Vegas over a variety of topologies including chain, grid, star, dumbbell and hammer, etc.

This paper addresses the problem of maximizing the protocol capacity of 802.11e networks, under the assumption that each access category (AC) has the same packet length. We prove that the maximal protocol capacity can be achieved at an optimal operating point with the medium idle probability of e−√2/T*c, where T*c is the duration of collision time in terms of slot unit. Our results indicate that the optimal operating point is independent of the number of stations and throughput ratio among ACs, which means the proposed analytical results still hold even when throughput ratio and station number are time-varying. Further, we show that the maximal protocol capacity can be achieved in saturated cases by properly choosing the protocol parameters. We present a parameter configuration algorithm to achieve both efficient channel utilization and proportional fairness in IEEE 802.11e EDCA networks. Extensive simulation and analytical results are presented to verify the proposed ideas.

In this paper, we present a new energy-efficient bandwidth allocation scheme for wireless networks. First of all, we investigate the intrinsic relationship between the energy consumption and transmission rates of mobile terminals, in which transmission rate is determined through channel allocations. Then, we propose two schemes for connection admission control: Victim Selection Algorithm (VSA) and Beneficiary Selection Algorithm (BSA) with the intent to reduce energy consumption of each terminal. Moreover, we introduce an adjustment algorithm to statistically meet the demands for quality of service (QoS) during the resource allocation. The performance of the proposed schemes is evaluated with respect to energy consumption rate of each successfully transmitted bit, throughput and call blocking probabilities. An extensive analysis and simulation study is conducted for Poisson and self-similar, multi-class traffic.