Title :
Interference suppression in CDMA downlink through adaptive channel equalization
Author :
Heikkila, Markku J. ; Komulainen, Petri ; Lilleberg, Jorma
Author_Institution :
Nokia Mobile Phones, Oulu, Finland
Abstract :
In the synchronous CDMA downlink using orthogonal spreading codes, the multiple access interference (MAI) is essentially caused by the multipath channel. This is why the MAI can be suppressed by channel equalization. In this paper we present a receiver algorithm which performs adaptive channel equalization by estimating the transmitted chip sequence. The adaptation uses Griffiths´ algorithm and converges to the LMMSE solution. The receiver is applicable in systems using long code scrambling such as in the 3rd generation wideband CDMA proposals, and it is shown to offer significant performance gains when compared to conventional RAKE receivers
Keywords :
adaptive equalisers; broadband networks; cellular radio; code division multiple access; convergence of numerical methods; interference suppression; least mean squares methods; multipath channels; multiuser channels; radio links; radio receivers; radiofrequency interference; sequences; spread spectrum communication; DS-CDMA system; Griffiths´ algorithm; LMMSE solution; RAKE receivers; adaptive channel equalization; cellular system; convergence; interference suppression; long code scrambling; multipath channel; multiple access interference; orthogonal spreading codes; performance; receiver algorithm; synchronous CDMA downlink; third generation wideband CDMA; transmitted chip sequence estimation; Adaptive equalizers; Code division multiplexing; Downlink; Interference suppression; Multiaccess communication; Multipath channels; Multiple access interference; Proposals; RAKE receivers; Wideband;
Conference_Titel :
Vehicular Technology Conference, 1999. VTC 1999 - Fall. IEEE VTS 50th
Conference_Location :
Amsterdam
Print_ISBN :
0-7803-5435-4
DOI :
10.1109/VETECF.1999.798476
