Adaptive MC-CDMA receiver with constrained constant modulus IQRD-RLS algorithm for MAI suppression

摘要

The multicarrier code division multiple access (MC-CDMA) technique is considered to be one of the attractive candidates to achieve high data-rate for future wireless communication systems. In this paper, based on linearly constrained constant modulus (LCCM) least square (LS) criterion, a new robust adaptive constrained filtering algorithm, referred to as the LCCM inverse QRD-RLS (IQRD-RLS) algorithm, is devised for MC-CDMA detector. The proposed robust LCCM IQRD-RLS algorithm can be used to estimate the weights of the combining process to combat the multiple access interference (MAI), effectively, and is more robust to against the imperfect channel estimation error. By this approach we require only the knowledge of code sequences of desired user rather than the code sequences of other users. The superiority of the proposed algorithm for estimating the weights in the combining process is verified by evaluating the performance, in terms of output signal to interference and noise ratio (SINR) and bit error rate (BER). From computer simulation results we showed that it outperformed the conventional techniques, such as the maximum ratio combining (MRC), blind adaptation algorithm, least mean square algorithm with partitioned linear interference canceller structure (PLIC-LMS) and LCCM-gradient based approaches.