TCP performance enhancement for mobile broadband interactive satellite communication system: A cross-layer approach

Mobile broadband interactive satellite communication system is of great interest in both research and development field. However, the conventional strict layered protocol stack architecture and the standard TCP version perform poorly over satellite link. In this paper, we propose a comprehensive cross-layer TCP optimization architecture while considering the main factors that affect the TCP performance. In our proposed architecture, we adopt two TCP split connection performance enhancing proxies to isolate the satellite link from the terrestrial part of the broadband satellite communication system. Then, we carefully optimize the TCP performance over the satellite link by jointly considering congestion control and flow control in transport layer, resource management mechanism and queue management policy in media access control layer. In addition, based on the proposed cross-layer architecture, we derive a close-form expression of TCP throughput by taking the modulation and coding mode, power allocation and channel state information in physical layer into account, and then put forward a TCP-driven adaptive modulation and coding scheme in satellite link. Extensive simulation results show our proposed comprehensive cross-layer TCP optimization approach not only improves the TCP throughput but also maintains a relatively low packet drop rate while using the bandwidth efficiently.