Pongsatorn SedtheetornKhairi Ashour HamdiLunchakorn WuttisittikuljitMahidol UniversityUniversity of ManchesterChulalongkorn University2018-05-032018-05-032011-06-01IEEE Transactions on Information Theory. Vol.57, No.6 (2011), 3405-3410001894482-s2.0-79957639895https://repository.li.mahidol.ac.th/handle/20.500.14594/11798In this paper, an efficient analytical technique for bit error rate (BER) of variable spreading gain code division multiple access (VSG CDMA) in Nakagami fading is introduced. Based on the accurate improve Gaussian approximation (IGA) technique, a new BER expression is derived in a closed form. Validated by Monte Carlo simulation, the proposed expression is used to accurately investigate the impacts of channel's conditions, power allocation and random users' distributions on the BER performance. © 2011 IEEE.Mahidol UniversityComputer ScienceSocial SciencesArticleSCOPUS10.1109/TIT.2011.2133670