Citation
Abstract
A new interpretation of unfiltered Feher-patented quadrature-phase-shift keying (FQPSK) is presented that readily identifies a means for spectral enhancement of the transmitted waveform as well as an improved method of reception. The key to these successes is the replacement of the half-symbol-by-half-symbol mapping originally used to describe FQPSK by a symbol-by-symbol mapping operation combined with memory. The advantages of such an interpretation are twofold. In particular, the original FQPSK scheme can be modiffed such that the potential of a waveform slope discontinuity at the boundary between half symbols is avoided without sacrificing the "constant" envelope property of the transmitted waveform, and, furthermore, a memory receiver can be employed to improve error-probability performance relative to previously proposed symbol-by-symbol detection methods. The analysis presented in this article does not include other versions of FQPSK such as FQPSK-B, which currently is being considered for military application.
Keywords
Details
- Volume
- 42-137
- Published
- May 15, 1999
- Pages
- 1–29
- File Size
- 733.5 KB