Constant-amplitude signaling for an extended parallel combinatory multicode system and improvement of its BER

A multicode transmission (MC) system can transmit multiple data streams at the same time, but it has a shortcoming in that the amplitude of the transmission signal has sharp fluctuations. This causes nonlinear distortion and results in degradation of the bit error rate (BER). To avoid this problem, this paper proposes an extension of a parallel combinatory multicode transmission with constant-amplitude signaling (PCMC-CA) system. The BER and data transmission rate of the proposed system were evaluated and compared with the performances of an MC with constant-amplitude signaling (MC-CA) system. The results showed that the proposed system has a higher data transmission rate than that of the MC-CA system. A demodulation method to improve the BER of the proposed system is also presented, and it is shown that the proposed system is likely to improve the BER.