A switching mechanism for Adaptive FEC in last hop wireless networks

Wireless networks make streaming video delivery very difficult due to high packet loss rate. Forward Error Control (FEC) has been adopted as a mechanism to overcome the high packet loss rate and improve video delivery over wireless channels. In this paper, a mechanism called Dynamic Switching-Research on Enhanced Adaptive FEC (DS-REAFEC) that dynamically adjusts the number of FEC packets to cope with the network conditions is proposed. DS-REAFEC is derived from the Research on Enhanced Adaptive FEC (REAFEC) scheme, a technique which adaptively computes the number x and y of FEC packets as a function of the traffic load and the retransmission times at the medium access layer of the base station and linearly combines both values to obtain the number of FEC packets to add to video data. The proposed DS-REAFEC mechanism differs to REAFEC in this, while REAFEC uses a static value of the linear combination parameter, DS-REAFEC tunes dynamically this value to cope with various network conditions. Simulation results conduct using the network simulator NS-2 and video trace files show an improvement in term of user-perceived quality for a streaming session of a video clip with sudden scene changes, when the network is experiencing a high packet error rate compare to REAFEC and the Enhanced Adaptive FEC (EAFEC) scheme.