Operational and fairness issues with connection-less traffic over IEEE802.11b

The IEEE802.11 group has recently ratified high rate (HR) extensions to enable high speed wireless communications over WLANs. The HR extensions specified in revision IEEE802.11b, encompass mainly new RF modulation schemes. This paper attempts an experimental evaluation of the performance characteristics of 802.11b in terms of throughput and loss over high speed transmission rates with respect to connection-less network traffic. We present a simple analysis of the protocol’s throughput capacity over high speed rates while we reveal fundamental design considerations that prevent 802.11b from reaching its true throughput potentials in the light of rate adaptivity. We further recommend some extensions to the Medium Access Control (MAC) protocol sub-layer that reconsider the multi-rate compatibility requirement while maintaining fairness in throughput between nodes at short or long distances within range from a Base Station (BS). The recommendations subject to simulations as work in-progress, expect to effect improvements in throughput over a proportionally-fair rate fallback scheme, in the order of 15% for transmission rates of 11 Mbps.We also provide some key observations to enable efficient protocol design for adaptive mobile environments. Keywords—802.11b, Medium Access Control, Point Coordination Function (PCF), Distributed Coordination Function DCF), Mobility, Dynamic Rate Fallback, Fairness.