Performance evaluation of video transmission with the PCF of the IEEE 802.11 standard MAC protocol

This paper focuses on a single BSA (Basic Service Area) in an infrastructur e network and studies the performance of the IEEE 802.11 standard MAC proto col by means of simulation. The MAC protocol supports DCF (Distributed Coor dination Function) and PCF (Point Coordination Function). The simulation mo del includes both data transmission with the DCF and H.263 video transmissi on with the PCF. In the simulation we assume that the channel transmission rate is 2 Mbps and use the system parameters specified in the standard for the DSSS (Direct Sequence Spread Spectrum) physical layer. We evaluate the performance of this protocol in terms of throughput and MPDU (MAC:Protocol Data Unit) delay for various values of the CFP (Contention Free Period) rep etition interval and the CFP maximum duration. Numerical results show that if the CFP repetition interval is set too long, video MPDU delay becomes ve ry large periodically; therefore; average video MPDU delay deteriorates. We also find that as the CFP maximum duration decreases, the number of video terminals that can be accommodated in the system decreases. Furthermore, ho w channel transmission errors affect the performance of the protocol is exa mined. A two-stare continuous-time Markov model is used as a burst error mo del. As a result, we see that for a small number of video terminals, the av erage video-MPDU-delay performance does not deteriorate drastically for lar ger values of bit error rate.