Near-Optimum Soft-Output Ant-Colony-Optimization Based Multiuser Detection for the DS-CDMA Uplink

— In this contribution, a novel soft-output Ant Colony Optimization (ACO) based Multi-User Detector (MUD) is proposed for the synchronous Direct-Sequence Code-DivisionMultiple-Access (DS-CDMA) uplink. The foraging behaviour of the ant colony in nature motivates the employment of reducedsearch ACO-based MUDs, which are capable of approaching the optimum Maximum Likelihood (ML) MUD’s performance at the cost of a computational complexity, which maybe as low as that of the Mathched Filter (MF) based Single User Detector (SUD). However, the previously proposed conventional ACO based MUDs were unable to provide soft Log-Likelihood Ratio (LLR) values for the channel decoder. Hence in this paper, we present a novel soft-output ACO-MUD capable of delivering soft LLRs, which allows a CDMA system to achieve a near-single-user performance without any additional information feedback from the channel decoder, even when the number of users supported is as high as the number of chip in the spreadi...

• Type: Conference
• Year: 2008
• Where: ICC
• Authors: Chong Xu, Lie-Liang Yang, Robert G. Maunder, Lajos Hanzo
• Keywords: Ant Colony, Channel Decoder, Communications, ICC 2008, Soft-output Ant Colony