A CFSK system with iterative detection
Xia Chen, Lance C. Pérez · 2005
A multiple access/multiple user system called collision frequency shift-keying (CFSK) is investigated. Maximum-likelihood sequence detection (MLSD) provides optimal multiuser detection for the CFSK system but is too complex for practical applications so iterative detection is investigated as a suboptimal approach. The MAP-consensus decoder is given as an example of iterative detection and studied for both the synchronous and asynchronous system. A channel interleaver is introduced so that the performance of the MAP-consensus decoder is asymptotically optimal. The metric of the CFSK system has nonpolynomial complexity so suboptimal metrics with linear complexity are considered. Simulation results show that iterative detection with reduced complexity metrics achieve good performance for moderate spreading factors.