Turbo-coded CDMA-based two-way relaying
Soon Xin Ng, Sha Sha Liao · ePrints Soton (University of Southampton) · 2012
In this contribution, we have studied the performance of a Turbo-Coded (TC) Code Division Multiple Access (CDMA) based two-way relaying scheme. More explicitly, we employ a seven-user CDMA model, where two of the CDMA users are communicating with each other with the aid of an additional relay node, while the other five CDMA users are interferers. More explicitly, two CDMA users exchange their information frames within two timeslots. Note that the conventional one-way relaying system can only transmit one information frame within two timeslots because the relay node is half-duplex, where it cannot listen and transmit simultaneously. We found that our proposed TC-CDMA two-way relaying scheme is capable of attaining over 4 dB of SNR gain at a Bit Error Rate (BER) of 10-6 when compared to a conventional non-cooperative TC-CDMA system. We also found that there is about two dB of SNR loss at a BER of 10-6, due to the error propagation from the relay node. The proposed scheme exploits the benefits of TC and CDMA schemes in order to assist the two-way relaying system to operate with a reduced transmit power. The reduction of the transmit power can also be exploited for increasing the coverage area of a cellular cell. Hence, the TC-CDMA two-way relaying scheme is a good candidate for future generation mobile systems