Receiver design for quasi-asynchronous MC-CDMA by using QCSS code

Abstract

Multi-carrier code division multiple access (MC-CDMA) communications scheme is a promising technology for future wireless communication systems. However, designing a receiver for quasi-asynchronous MC-CDMA and corresponding code still dates a challenging task. We show that fractional-delay uplink channels, suffer while complete complementary code (CCC) and Walsh-Hadamard (WH) code are used. Thus quasi-asynchronous MC-CDMA system introduces a very high multiple access interference (MAI) at the receiver's output, due to which the system performance may degrade. In this paper we have designed a transceiver for quasi-asynchronous MC-CDMA by using a quasi-complementary sequence sets (QCSS) refer to a set of two-dimensional matrices which have non-zero (low) aperiodic auto — and cross — correlation sums. The proposed transceiver based on QCSS is an interference-free for quasi asynchronous MC-CDMA system and provides better performance than that of CCC and WH based quasi asynchronous MC-CDMA.