Performance comparison of orthogonal multicarrier DS-CDMA systems in frequency selective slow-fading channels

This paper analyses the performance of orthogonal multicarrier DS-CDMA systems for personal communications. The basic system operates using the orthogonal multicarrier technique combined with direct sequence code division multiple access. The non-stationary behaviour of the channel is tracked by a periodic sounding. This technique leads to relatively simple receivers that can be implemented with current VLSI and DSP technology. Taking into account the challenges related to an up-link implementation, the system performance in the down-link is investigated both for synchronous and asynchronous DS-CDMAs. In particular, the schemes which work with Walsh sequences (in the synchronous case) are compared with the schemes operating by binary Gold sequences and 4-phase near-optimal sequences (in the asynchronous case). The comparison is carried out on the basis of significant parameters such as bit error rate, spectral efficiency and multipath counteraction for different system configurations.