Phase ambiguity resolution in a 4-phase PSK modulation system with forward-error-correcting convolutional codes
Abstract
The usual method of differential coding or a synchronization word to resolve the phase ambiguity of a reference carrier at a receiver side has a substantial drawback when used with forward error correcting (FEC) codes, i.e., one erroneously detected phrase will cause two consecutive false symbols (a burst error) even if the next phrase is received correctly. This paper describes two methods of resolving phase ambiguity with FEC. In one, differential coding is used inside an FEC codec in conjunction with an interleaving technique. In the other, a syndrome pattern resolves the primary ambiguity, which is followed by differential coding outside an FEC codec to resolve the remaining ambiguity. The first method can be used with a burst mode operation, e.g., TDMA or SPADE; the second method is found superior in terms of lowering the bit error rate.
- Publication:
-
COMSAT Technical Review
- Pub Date:
- November 1977
- Bibcode:
- 1977COMTR...6..357T
- Keywords:
-
- Ambiguity;
- Data Transmission;
- Error Correcting Codes;
- Phase Shift Keying;
- Signal Encoding;
- Bit Synchronization;
- Convolution Integrals;
- Error Analysis;
- Phase Error;
- Resolution;
- Time Division Multiple Access;
- Transmission Efficiency;
- Communications and Radar