Application of Modified Particle Swarm Optimization Algorithm to Multi-user Detection in DS-UWB System

• Main Authors: Chiu-Chun Cheng, 鄭秋君
• Other Authors: 譚旦旭
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/5775da

碩士 === 國立臺北科技大學 === 電機工程系所 === 95 === For the multi-user application, the multiple access interference (MAI) due to imperfect orthogonality between spreading codes induced by UWB dense multi-path degrades system performance. Though optimum multi-user detector (OMD) can achieve remarkable performance, its computational complexity is too high to implement. Therefore, many sub-optimal multi-user detectors (MUDs) have been proposed to attain best trade-off between performance and complexity, such as Genetic algorithm-based multi-user detector (GA-MUD). However, BER performance of GA-MUD is not good enough and its convergence rate is slow. In order to increase the convergence rate and BER performance, we apply Particle Swarm Optimization algorithm (PSO) to replace GA to develop a new PSO-based MUD. This MUD employs rake receiver to generate initial solution for PSO-based optimization. Moreover, we combine mutation mechanism of GA to PSO for increasing diverseness of particles in searching space which is called PSO_Mutation-MUD. Experimental results show that the proposed PSO_Mutation-MUD attains highest gain in the CM4 environment. We also compare the performances between PSO_Mutation-MUD, PSO_CW-MUD, PSO_TCAV-MUD, and GA-MUD. The result reveals that our proposed PSO_Mutation-MUD yields the best performances over UWB channels.