A Joint Chip Equalization Adaptive Rake Receiver for DS-CDMA UWB Systems over ISI Channels

Abstract

There is serious inter-symbol interference (ISI) when ultra-wideband (UWB) wireless communication systems work at high data speed since there is much larger channel delay spread. The serious ISI becomes a major factor that affects the performance of UWB systems. In this paper, suppression ISI is developed for direct sequence spread-code division multiple access (DS-CDMA) UWB systems with a high data speed, and a joint chip equalization adaptive Rake (JCE-Rake) receiver is proposed. The proposed JCE-Rake receiver spreads the number of traditional Rake receiver taps to collect multi-path component and equalize the inter-chip interference simultaneously. Then the soft output of JCE-Rake receiver is despreaded with the user's spreading code. Finally the decision is made to recover the transmitted symbol. The simulation results verify that ISI is suppressed effectively and the system performance is improved evidently.