Subchannel Allocation for Multicarrier CDMA with Adaptive Frequency Hopping and Decorrelating Detection

Multicarrier code-division multiple access (MC-CDMA) system with adaptive frequency hopping (FH) has attracted significant attention in the literature due to its excellent spectral efficiency. A suboptimal water-filling (WF) channel allocation algorithm was previously proposed for the conventional matched filter (MF) detector in the reverse link of this system. However, the performance of the WF algorithm is degraded by the fading-induced near-far problem. We propose a new allocation algorithm to overcome the limitations of the WF algorithm, and demonstrate the resulting BER improvement using simulation. Moreover, we employ the linear decorrelating detector at the receiver of the MC-CDMA system with adaptive FH to improve the spectral efficiency. The proposed allocation algorithm is also extended to this receiver by exploiting the SNR analysis of decorrelator. We demonstrate that the linear decorrelating detector that employs the proposed allocation algorithm is very effective in mitigating MAI, with performance approaching the single user bound for MC-CDMA system with adaptive FH