Throughput improvements for FHMA wireless data networks employing variable rate channel coding

The increasing need for secure, high throughput wireless data networks has led to a search for spectrally efficient wireless systems which make better use of the available bandwidth. We propose that greater spectral efficiency can be achieved in Frequency Hopped Multiple Access (FHMA) networks by improving the coding efficiency of these systems through a technique called Variable Rate Coding (VRC). With VRC, an adaptable code rate is employed during communication allowing a transmitter-receiver pair to adapt the amount of redundancy provided by an error correction code to the quality of the channel. This is opposed to a Fixed Rate Coding (FRC) scheme in which a fixed code rate is utilized to provide sufficient protection for the worst case channel conditions. If the quality of the channel can be accurately estimated during communication, we show that VRC can provide significant throughput advantages over traditional FRC schemes for non-orthogonally hopped FHMA networks.