Multiuser detection for continuous phase modulation over Rayleigh fading channels

We study multiuser (MU) continuous phase modulation (CPM) over Rayleigh fading channels with a receiver antenna array. An optimum symbol-by-symbol MU detector is derived and its practical implementation with reduced-complexity is considered. According to the numerical results, the MU detector performs very close to a system free of interference by other users, when each user has more than one receiving antenna. For three receiving antennas, this difference is less than 0.25 dB, 0.4 dB, and 0.6 dB for two, three and four users, respectively. Moreover, the proposed system is bandwidth efficient as CPM is a bandwidth efficient modulation scheme, and the MU system only uses the single user CPM bandwidth.     

Serially Concatenated Space-Time Coded Continuous Phase Modulated Signals

We investigate the detection of space time codes (STC) modulated using continuous phase modulation (CPM), in quasi-static fading channels. A symbol-by-symbol iterative detector with an optimum front-end is derived, and its reduced-complexity implementation is considered. Also, we have introduced several full-rank STC-CPM systems, constructed by combining full-diversity STCs with simple, widely-used CPM schemes, and introducing a small frequency offset. According to the simulation results, the bit error rate (BER) performance of the detector for quasi-static fading is around 1 dB from the case without fading. Furthermore, a comparison of the performance of the proposed detector with results from previous work on STC-CPM showed an improvement in the range of 2-3 dB. Moreover, the detector is robust to the errors in estimating the channel state information (CSI), which is a desirable feature for practical implementation.