A multi-tiered scheme for interference control in a wireless system

We analyze a scheme that combines ARQ, FEC, frequency hopping (FH) and traffic rate control to mitigate the effects of interference on the performance a fixed wireless system. ARQ is ineffective because of excessive retransmissions; FEC also becomes ineffective when excessive coding redundancy is required for adequate error correction. When interference is widespread across the channels, FH becomes ineffective as well. Additional interference control may therefore be needed. In this paper, we study two heuristic schemes that throttle the incoming traffic rate according to the level of interference in the transmission channels, where FH, ARQ and FEC are already employed. We analyze and compare the throughput, delay and loss of the two rate controls in combination with FEC and FH. The results show that by optimizing it with respect to a measure of power (throughput/delay), one of the schemes performs best across the load, and its performance can be further enhanced by FEC.