Ahmet Bastug

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The payload increase of watermarking channels via the use of low-density parity check codes is considered. The bit error rate and payload size problem is addressed in the light of the performance of typical transform-domain spread-spectrum watermarking techniques. Simulation results indicate that the information payload can be doubled via judicious use of(More)
We consider a family of user dedicated downlink channel estimation methods in WCDMA receivers which are particularly suited for the presence of dedicated channel transmit beamforming and which assume no a priori knowledge of the path delays and the beamforming parameters. They exploit all the transmitted pilot sequences as well as the structured dynamics of(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)
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)
In this paper we consider iterative techniques for multi-user detection. In the overdetermined case in which signal and noise subspaces exist, polynomial expansion can perhaps most conveniently be applied to a global MMSE ZF linear receiver. In the resulting iteration sections, we then propose to replace the various receiver components by a (possibly(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)
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)