Abstract: Due to the characteristic of the DVB-RCS，long latency and high bit error probability will influence the performance of the TCP traffic.The traditional protocol design method don’t adapt to the dynamic variable network.This paper proposes the cross layer design scheme which combined the transport layer’s characteristic of TCP，the access scheme of MAC layer and the adaptive modulation and coding of physical layer to increase the performance of TCP.The simulation results show that compared with traditional method，the cross-layer scheme can increase the delay performance and channel utilization.

Key words: broadband satellite network, cross-layer design, bandwidth allocation, Quality of Service（QoS）

摘要： 由于DVB-RCS网络长传播延迟以及高误码率的特点，会造成所承载TCP业务的性能下降。传统的分层协议设计方式已经不适合这种动态变化的网络特点。采用跨层协议设计方式优化TCP协议性能。跨层设计方式结合了传输层上TCP协议的工作特点，MAC层的接入策略以及物理层上的自适应调制编码策略。仿真结果显示了跨层协议设计相对于传统协议设计方式性能上的优势。

关键词: 宽带卫星网络, 跨层设计, 带宽分配, 服务质量