We investigate the performance of several suboptimal multiuser detectors for rapidly time varying mobile radio channels. A modified Jakes model is used to simulate a realistic mobile fading channel. The use of the Kalman filter for this channel model is examined. We also analyze the performance of several noncoherent multiuser detectors. Analysis and simulation results indicate that the decorre...

In this paper we investigate multiuser detection techniques for coded narrowband signals in fading channels. In [1], Moher proposed a suboptimal multiuser detector and its performance is demonstrated for the AWGN channel. In this paper, this multiuser detector is modified for fading channels, such as the Rayleigh fading channel model. The fading channels described and simulated are flat narrowb...

A linear multiuser receiver for a particular user in a CDMA network gains potential beneets from knowledge of the channels of all users in the system. In fast multipath fading environments we cannot assume that the channel estimates are perfect and the inevitable channel estimation errors will limit this potential gain. In this paper we study the impact of channel estimation errors on the perfo...

This paper studies the performance of iterative multiuser decoding, interference cancellation, and channel estimation techniques applicable to third generation WCDMA systems. The concept uses a posteriori probabilities of code symbols to enhance detection, decoding and channel estimation in an iterative fashion. Performance is analyzed in a multi-path channel with simulations. It is seen that t...

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In this paper, we develop an iterative multiuser receiver for decoding Turbo coded synchronous CDMA signals in both Gaussian and non-Gaussian noise. A soft-input soft-output non-linear multiuser detector is combined with a set of single user channel decoders in an iterative detection/decoding structure. The non-linear multiuser detector utilizes the prior probabilities of each user's bits to fo...

A linear multiuser receiver for a particular user in a code-division multiple-access (CDMA) network gains potential benefits from knowledge of the channels of all users in the system. In fast multipath fading environments we cannot assume that the channel estimates are perfect and the inevitable channel estimation errors will limit this potential gain. In this paper, we study the impact of chan...

This paper considers the optimal multiuser detection problem for the vector Gaussian multiple access channel with multiple inputs and multiple outputs (MIMO). A practical bit-loading and multiuser decision feedback scheme based on generalized decision feedback equalization (GDFE) is proposed. This GDFE-based detection scheme, when used with an optimized transmitter, achieves the extreme points ...

~ince the Co.de Division Multiple Access (CDMA) system was proposed for the next generation of mobile communications, several multiuser detection· methods have been develope? to cope with the Multi-Access Interference inherent in the CDMA system. Fading and. multIpath ch~acteristi~sof the mobile radio channel present significant challenges to the designer of multiuser receivers. The fading phen...

We consider the problem of downlink scheduling for multiuser orthogonal frequency-division multiplexing (OFDM) systems. Opportunistic scheduling exploits the time-varying, location-dependent channel conditions to achieve multiuser diversity. Previous work in this area has focused on single-channel systems. Multiuser OFDM allows multiple users to transmit simultaneously over multiple channels. I...