Owing to ideal correlation properties of complementary codes (CCs), a complementary coded code-division multiple-access (CC-CDMA) system outperforms traditional CDMA systems in terms of its interference-resistance capabilities. However, it may lose its interference-resistance feature and suffer performance degradation over asynchronous frequency-selective fading channels due to the fact that it is incapable of reconstructing ideal complementary cross-correlation functions at a receiver. Based on the analysis on combining and detection algorithms designed for CC-CDMA systems, this paper proposes a joint pre-equalization and adaptive combining scheme. Pre-equalization is used at a transmitter to either enhance diversity gain or compensate channel selectivity leveraged by a controlling parameter ζ, whereas a recursive least square (RLS) adaptive combining algorithm is employed at a receiver to determine the optimal combining coefficients, aiming at minimizing detection errors under different channel conditions. Simulation results show the superiority of the proposed scheme in terms of bit error rate (BER) and its adaptability to varying channel states.
All Science Journal Classification (ASJC) codes
- Automotive Engineering
- Aerospace Engineering
- Applied Mathematics
- Electrical and Electronic Engineering