Coherent multicarrier/DS-CDMA and MC-CDMA for broadband packet wireless access

This paper compares the packet error rate (PER) performance levels of 3 access schemes, i.e., single-carrier (SC)/DS-CDMA, multi-carrier (MC)/DS-CDMA, and MC-CDMA assuming an over 100-MHz bandwidth for broadband packet wireless access. In a broadband propagation channel, severe multipath interference degrades the accuracy of path search and channel estimation for coherent detection. Computer simulation results show that, in the reverse link, SC/DS-CDMA achieves better performance than MC/DS-CDMA because the pilot signal power in one sub-carrier for path search and channel estimation decreases as the number of sub-carriers increases. The superiority of MC-CDMA to MC(SC)/DS-CDMA is demonstrated, and the results show that, in the forward link, frequency Rake diversity with MC-CDMA is more effective than time Rake diversity with DS-CDMA in a broadband multipath fading channel due to a large amount of multipath interference.