Radio-Aware TCP Optimization in Mobile Network

As a transport layer protocol, TCP is widely used in the various applications especially for video transmission in the mobile network. The TCP protocol not only provides an end-to-end connection to guarantee the reliability and in-order delivery of packets, but also shapes the transmission rate from the server to client through the mobile network. In wireless link, the available bandwidth varies significantly due to the changes in the underlying radio channel conditions. Traditional TCP congestion control has difficulties in adapting to these rapidly varying conditions which leads to low throughput and long delay. This paper analyzes the TCP issues in the mobile wireless network, and proposes two radio-aware TCP optimization solutions. The loose coupled radio-aware TCP optimization solution controls the parameters of TCP layer according to the cross-layer information which includes the client predicted rate and low layer's assisted information, while the close coupled radio-aware TCP solution modifies the traditional TCP congestion control mechanism to a novel TCP request-grant mechanism. The simulation proves the solutions can acquire significant TCP performance gain with extreme low latency.