A promising set of spreading sequences to mitigate MAI effects in MIMO STS systems

Abstract

Multiple input, Multiple output space time spreading (MIMO STS) system is a scheme which can provide full diversity gain without extra resource requirements. However, its performance degrades significantly when multiple access interference (MAI) occurs. In order to mitigate MAI effects, we propose a criterion to build a promising set of combination of spreading sequences for users. Simulation results show that the average BER performance of users using this promising set is about thirty percent lower than that of users using another set in case of 64 chip length Walsh-Hadamard code. Abstract-Multiple input, Multiple output space time spreading (MIMO STS) system is a scheme which can provide full diversity gain without extra resource requirements. However, its performance degrades significantly when multiple access interference (MAI) occurs. In order to mitigate MAI effects, we propose a criterion to build a promising set of combination of spreading sequences for users. Simulation results show that the average BER performance of users using this promising set is about thirty percent lower than that of users using another set in case of 64 chip length Walsh-Hadamard code.