Supporting service differentiation with enhancements of the IEEE 802.11 MAC protocol: Models and analysis

Abstract

Abstract. As one of the fastest growing wireless access technologies, Wireless LANs must evolve to support adequate degrees of service differentiation. Unfortunately, current WLAN standards like IEEE 802.11 Distributed Coordination Function (DCF) lack this ability. Work is in progress to define an enhanced version capable of supporting QoS for multimedia traffic at the MAC layer. In this paper, we aim at gaining insight into three mechanisms to differentiate among traffic categories, i.e., differentiating the minimum contention window size, the Inter-Frame Spacing (IFS) and the length of the packet payload according to the priority of different traffic categories. We propose an analysis model to compute the throughput and packet transmission delays. In additions, we derive approximations to get simpler but more meaningful relationships among different parameters. Comparisons with discrete-event simulation results show that a very good accuracy of performance evaluation can be achieved by using the proposed analysis model.

Achieving End-to-end Fairness in 802.11e Based Wireless Multi-Hop Mesh Networks Without Coordination

“…This can be achieved by using a smaller value of CW min for the prioritised traffic class at the station. It is shown in [4] that competing traffic classes gain transmission opportunities approximately in inverse proportion to their values of CW min . Let k denote the ratio of the stations CW min value to the base value used in the network (e.g.…”

“…7 using a test-bed constructed from Soekris net4801 4 stations with Atheros 802.11a/b/g miniPCI cards. All stations run the Linux 2.6.21.1 kernel with a version of the MADWiFi 5 wireless driver which is customised to allow the prioritisation described in this paper.…”

Achieving Optimal Performance by Using the IEEE 802.11 MAC Protocol With Service Differentiation Enhancements

“…To make this paper self-contained, in this section, we briefly summarize the model and analysis that are presented in [20] and [21], dealing with extensions of DCF to support service differentiation. All details about the analysis can be found in [20].…”

“…However, the model is complex, which makes it difficult to obtain deeper insight into the system performance. Li and Battiti [20], [21] propose a simple analysis model to compute the throughput in a wireless 0018-9545/$25.00 © 2007 IEEE local area network with enhanced IEEE 802.11 DCF. In the proposed analytical model, service differentiation is supported by differentiating the minimum CW size and the IFS according to the priority of each traffic flow.…”

“…In this paper, based on our former work described in [20] and [21], we successfully analyze the optimal operation point where maximum saturation throughput can be achieved. It is worth noting that we confine our discussions only for the case where equal IFSs are adopted for different traffic flows.…”