Performance Analysis of Packet Aggregation in WLANs with Simultaneous Multi-user Access

摘要

A cross-layer wireless LAN system is considered which transmits packets for a number of users simultaneously using OFDMA or SDMA transmission. Due to varying packet lengths and physical bitrates for each user, this results in different transmission times so that users with faster transmissions have to wait until the transmission of the slower users is complete. Packet aggregation can reduce the loss of airtime and enhance the throughput without affecting the delay by filling in the gaps with additional packets which are ready for transmission. In this paper, the throughput is determined analytically and by simulation with and without packet aggregation for some given distribution functions of the packet size and the transmission time. For a more realistic channel model, the throughput enhancement due to packet aggregation is determined by simulations. It is shown that dependent on the distribution of the different flows, a significant throughput enhancement can be achieved.