{"title":"NDA chip synchronization for bandlimited DS/SS M-PSK signals using CDMA with unequal power levels on nonselective fading channels","authors":"K. Goethals, M. Mieneclaey","doi":"10.1109/MILCOM.1994.473901","DOIUrl":null,"url":null,"abstract":"Derives two maximum-likelihood (ML) oriented nondecision-aided (NDA) chip synchronization algorithms for bandlimited direct-sequence spread spectrum (DS/SS) M-PSK signals transmitted over a nonselective fading channel. The authors also investigate their tracking performance in the presence of multi-user interference in a code-division multiple access (CDMA) system where the users have unequal power levels. The performance of the non-channel aided (NCA) algorithm was found to be independent of the fading characteristics, whereas the channel aided (CA) algorithm is influenced by the carrier-to-multipath ratio C/M, but not by the fading bandwidth. For practical E/sub s//N/sub 0/, the NCA algorithm outperforms the CA algorithm, whose performance degrades with decreasing C/M. The performance of both algorithms is better for synchronous than for asynchronous CDMA. For large signal-to-noise ratio, the tracking error variances approach asymptotic values that are inversely proportional to the ratio of the reference user power to the total power of the multi-user interference.<<ETX>>","PeriodicalId":337873,"journal":{"name":"Proceedings of MILCOM '94","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"1994-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"2","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Proceedings of MILCOM '94","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1109/MILCOM.1994.473901","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 2
Abstract
Derives two maximum-likelihood (ML) oriented nondecision-aided (NDA) chip synchronization algorithms for bandlimited direct-sequence spread spectrum (DS/SS) M-PSK signals transmitted over a nonselective fading channel. The authors also investigate their tracking performance in the presence of multi-user interference in a code-division multiple access (CDMA) system where the users have unequal power levels. The performance of the non-channel aided (NCA) algorithm was found to be independent of the fading characteristics, whereas the channel aided (CA) algorithm is influenced by the carrier-to-multipath ratio C/M, but not by the fading bandwidth. For practical E/sub s//N/sub 0/, the NCA algorithm outperforms the CA algorithm, whose performance degrades with decreasing C/M. The performance of both algorithms is better for synchronous than for asynchronous CDMA. For large signal-to-noise ratio, the tracking error variances approach asymptotic values that are inversely proportional to the ratio of the reference user power to the total power of the multi-user interference.<>