Alexandra Duel-Hallen

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Several multiuser detectors for code-division multiple-access (CDMA) systems have been studied recently. We propose a new decorrelating decision-feedback detector (DF) for synchronous CDMA which utilizes decisions of the stronger users when forming decisions for the weaker ones. The complexity of DF is linear in the number of users, and it requires only one(More)
Recently it was proposed to adapt several transmission methods, including modulation, power control, channel coding and antenna diversity to rapidly time variant fading channel conditions. Prediction of the channel coefficients several tens-to-hundreds of symbols ahead is essential to realize these methods in practice. We describe a novel adaptive long(More)
Present day direct sequence code division multiple access (DS/CDMA) systems treat each user separately as a signal, with all ofthe other users representing interference or noise. Potentially significant capacity improvements can be achieved if the negative effect that each user has on the others is cancelled. In other words, joint detection (multiuser(More)
In wireless communication systems, the direct signal and the reflected signals form an interference pattern resulting in a received signal given by the sum of these components. They are distinguished by their Doppler shifts at the mobile. Once the slowly varying parameters associated with these components are determined, the fading coefficients can be(More)