FQPSK With an Outer Code for Greater Efficiency

A proposed method of FQPSK modulation and demodulation of a radio signal would incorporate any of a number of relatively simple (short-constraintlength) outer codes. By affording significant coding gains even when using a reduced-complexity (and thus suboptimal) FQPSK receiver, this method would offer the concomitant potential to enhance efficiency in power and spectral width of an FQPSK communication system.