Dynamic MAC Parameters Configuration for Performance Optimization in 802.11e Networks

Quality of service support in wireless LAN is a theme of current interest. Several solutions have been proposed in literature in order to protect time-sensitive traffic from best-effort traffic. According to the EDCA proposal, which is a completely distributed solution, the service differentiation is provided by giving probabilistically higher number of channel accesses to stations involved in real-time applications. To this purpose, the MAC parameter settings of each contending stations can be tuned dynamically. In this paper, we face the problem of tuning the EDCA MAC parameters in common scenarios in which a given number of low-rate delay-sensitive traffic flows share the channel with some stations involved in data transfer. Our contribution is threefold. First, we show that, whenever possible, the delay constraints of the high priority class can be satisfied in both the cases of contention windows differentiation and inter-frame space differentiation. However, these mechanisms have different side effects in terms of bandwidth availability for the best effort stations. Second, we propose to exploit the MAC parameter dynamic settings of EDCA in order to probabilistically guarantee the delay requirements and to jointly maximize the aggregated throughput of the network. Finally, we suggest a very simple solution to automate these parameter settings in a real scenario, where traffic flows can be activated/deactivated dynamically, by simply monitoring the channel activity. The proposed solution is very robust, since it does not require any a priori traffic model or any network load estimator

Performance evaluation of IEEE 802.11

This paper analyzes the performance of IEEE 802.11 MAC protocol under a disaster scenario. The performance is measured in terms of the recovery time and the throughput of the protocol when a network disaster occurs. To make the problem amenable to analysis, some approximations are used, and a new technique to collapse a very large state space is introduced. The analytical results are found to agree with simulations

Comments on the paper 'Analysis of collision probabilities for saturated IEEE 802.11 MAC protocol'

The present authors would like to point out that the observation where the channel collision probability depends on whether the channel was busy or idle discussed by Kuan and Dimyati has been reported earlier by the present authors, Foh and Tantra. © The Institution of Engineering and Technology 2007

Achieving near maximum throughput in IEEE 802.11 WLANs with contention tone.

Future wireless local area networks (WLANs) promise bit rates higher than 100 Mbps. Previous research by Xiao et al. reported that the current IEEE 802.11 medium access control (MAC) protocol does not scale well to high bit rate channels. In this letter, we propose an enhancement that uses contention-tone transmitted on a separate narrow band signaling channel. The proposed contention tone mechanism avoids more than 96% of transmission collisions, hence achieving near to the theoretical maximum throughput of a WLAN MAC protocol. © 2006 IEEE

Achieving near maximum throughput in IEEE 802.11 WLANs with contention tone

Future wireless local area networks (WLANs) promise bit rates higher than 100 Mbps. Previous research by Xiao et al. reported that the current IEEE 802.11 medium access control (MAC) protocol does not scale well to high bit rate channels. In this letter, we propose an enhancement that uses contention-tone transmitted on a separate narrow band signaling channel. The proposed contention tone mechanism avoids more than 96% of transmission collisions, hence achieving near to the theoretical maximum throughput of a WLAN MAC protocol. © 2006 IEEE