Hybrid FEC/ARQ schemes for real-time traffic in wireless networks

Real-time applications over wireless networks often suffers from jitter, delay and packet loss. The traditional techniques for error control are FEC (Forward Error Correction) and ARQ (Automatic Repeat Request). In this paper a hybrid FEC/ARQ mechanisms with limiting the slots number between the loss of the last retransmission of the original block n and the reception of block n + φ is analyzed in an environment of real time applications. We assume that the packet size increases when adding redundancy so that the amount of useful information contained in a packet is unchanged. We evalute analytically the performance of TFRC (TCP Friendly Rate Control) and ARC (Analytical Rate Control Protocol) as a function of the parameters of the FEC scheme, the limit number of retransmission used by ARQ scheme and the number of slots threshold Sth. We show that the combination of FEC and ARQ with limiting the Sth reduces the number of retransmissions and keeps a reasonable delay for real time traffic in wireless networks.