A proxy-based rate control strategy of streaming media distribution in heterogeneous access environments

摘要

This paper proposes a proxy-based rate control strategy of streaming media distribution for multiple clients in heterogeneous access environments. Take access network condition into consideration, our architecture includes sender functionality on proxy side and receiver functionality on client side, which uses bit error ratio (BER) and packet loss ratio (PLR) to provide two-tier rate control. In the first tier, BER is adopted as a feedback parameter from transport layer to application layer, which can be used to calculate optimal packet size and current delay. If current delay is greater than the maximum, optimal packet size is fed back to sender. In the second tier, TCP-Friendly Rate Control (TFRC) equation is introduced to calculate the maximal available receiving rate based on RTT, RTO and PLR evaluation. PLR is corrected by BER information for wireless access clients. In order to decrease the number of RTT requests, hybrid RTT estimation scheme is adopted. In addition, receiver-active dropping policy is proposed to remove error propagation. Simulation results demonstrate effectiveness of our proposed schemes.