CBA-TCP: A cross-layer TCP transmission rate adaptation scheme based on the compressed block ACK bitmap of IEEE 802.11n networks

Optimizing the performance of TCP in wireless networks in a changing network condition is a highly challenging issue. The lack of information at the TCP layer about the link quality will result in inaccurate transmission rate. Therefore, TCP needs to have sufficient information about the environment and the different characteristics of the lower layers to improve the performance. To achieve this goal we proposed a cross-layer scheme which makes use of the information stored in the 802.11n compressed block acknowledged bitmap about the status of the transmitted subframes of the aggregated frame. This information is fed to the TCP transmission mechanism as a new criterion to adjust the TCP transmission rate with accordance to the aggregation level and channel quality. The simulation results show that the proposed scheme improves the TCP performance in term of throughput and packet loss.