To analyze the saturation performance of IEEE 802.11 DCF, several discrete-time Markov chain models for a station and sets of channel equations have been introduced. We take into account a frame retry limit, freezing of backoff counter, and the dependence of backoff procedure on the previous channel status all together. Our method is simple even though it is accurate under the assumption of no consecutive transmissions over the shared channel.

Various co-sited wireless communication systems may share the same frequency band. This causes mutual interference between the wireless communication systems, and degrades the performance of each wireless communication system. In this paper, we analyze the effect of mutual interference between WiFi and WiMAX systems sharing the same frequency band. We propose novel methods based on a proposed coexistence zone within the WiMAX frame structure and a modified power saving mode of the WiFi system to solve the problem. We evaluate the performance of the proposed methods by computer simulation.