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In this paper we consider iterative receiver techniques for the downlink in WCDMA systems (UMTS FDD mode). We start from the linear MMSE receiver (at symbol level), which is time-varying and hence too complex to implement. By applying polynomial expansion (PE) to the LMMSE receiver, an iterative soluton is obtained in which the complexity per iteration(More)
UMTS-FDD mode downlink system is in practice supposed to be partially loaded due to interference limitations. In other words, some of the orthogonal codes are not used. This indicates that the system is overdetermined and there exists a noise space which can be exploited to cancel the intracell and intercell interference. However, since the scramblers that(More)
A general method for user dedicated downlink channel estimation in WCDMA receivers is addressed, particularly suited in the presence of dedicated channel transmit beamforming. A three-step dedicated channel estimation procedure is derived which exploits all the existing pilot sequences as well as the structured dynamics of the channel. In the first step,(More)
We consider iterative WCDMA receiver techniques for the UMTS FDD downlink. The popular LMMSE chip equalizer-correlator receiver does not exploit subspaces in partially loaded systems. This is in contrast to the symbol level LMMSE receiver, which is time-varying though, due to the scrambler, and hence too complex to implement. A compromise can be found by(More)
We consider high speed packet data access service (HSDPA) which is introduced with the Release-5 of the UMTS-FDD standard. Signal to interference plus noise ratio (SINR) and throughput bounds from the usage of channel matched filter (RAKE in FIR form) and LMMSE equalizer plus correlator type mobile terminal receiver structures are obtained for the high(More)
Estimation of time-varying channel parameters in the existence of aperiodic codes (UMTS FDD mode downlink) is considered. In the first stage, a coarse FIR channel estimate is obtained in every slot via the pilot channel. In the second stage, the estimate is improved by Wiener filtering across slots, modeling the channel parameters as first order(More)
  • A. Bastug
  • 2004
An LMMSE-variant chip equalizer and an MMSE symbol estimator are discussed for the UMTS FDD mode. Since the scrambler is aperiodic in the downlink, the LMMSE (linear MMSE) receiver has to be adapted at the chip rate. By modeling the scrambler as a stationary random sequence, however, a max-SINR equalizer-correlator structure, which may be adapted at the(More)
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