Performance complexity of raptor codes in TCP/IP-based wireless networks

This paper assesses the enhancement of TCP-SACK using a new error correction mechanism. Performance metrics like packet recovery rate and throughput are applied as a function of packet loss rate. The raptor standalone module is built and implemented in ns2. While our results show higher throughputs and recovery rates, we demonstrate that this comes at the expense of increased decoding complexity. Three additional performance metrics are used to quantify the decoding complexity: row swap operations, delay and redundancy rate. Each was measured as a function of symbol packet length. The results show an increase in redundancy rate as the block length increases. When compared with Luby Transform (LT) codes, we see a significant reduction in the redundancy introduced by raptor codes. The same can be said about the delay involved in the process. It also increased as the packet symbol length increased. Likewise, with larger packet length, a considerably larger number of row swap operations will be required.