On the performance comparison of VSF-OFCDMA and OFDMA

In this paper, we compare the downlink capacity and throughput between the variable spreading factor-orthogonal frequency and code division multiple access (VSF-OFCDMA) with one-cell frequency reuse, and the orthogonal frequency division multiple access (OFDMA) with conventional three-cell frequency reuse. Since the multiuser diversity gain in OFDMA systems can be achieved by approximately designing its access schemes, while it is non-trivial for the VSF-OFCDMA systems, the effect of both access schemes on the link capacity are investigated. Our simulation results reveal that although the multiuser diversity gain achieved by OFDMA systems can compensate the loss of low frequency reuse at low to mid range of signal-to-interference-plus-noise ratio (SINR) values, the achievable throughput of VSF-OFCDMA systems is much higher than the OFDMA systems. Furthermore, the impact of userpsilas location on the inter-cell-interference is also reported.