SUBCARRIERS-CODE DIVISION MULTIPLE ACCESS (SCCDMA): A NEW ACCESS SCHEME FOR 4G MOBILE COMMUNICATION SYSTEMS

摘要

Multicarrier Code Division Multiple Access (MC-CDMA) and Orthogonal Frequency Division Multiple Access (OFDMA) schemes have achieved high interest for 4G mobile communication systems. In a single cell, due to inter-symbol interference (ISI) and intercarrier interference elimination, OFDMA system can adaptively assign spectrum resources, but can not flexibly realize frequency reuse in a multi-cell system. MC-CDMA system implements frequency reuse with reuse factor equal to 1 but introduces the new multi-user interference. In this article, a novel downlink access scheme, which possesses the advantages of OFDMA and MC-CDMA, named Subcarriers-Code Division Multiple Access (SCCDMA) is proposed. The paper presents the principle and construction of the new scheme based on Subcarriers Code (SCC) units, analyzes the characteristics and evaluates the performances of SCCDMA compared with OFDMA and MC-CDMA, at last presents some simulation results on the downlink performance in a frequency-selective Rayleigh fading environment.