943 research outputs found
Performance of a linear interference canceller for a ds/cdma synchronous system based on the ekf delay estimator
Since the conventional detector often fails to produce reliable decisions for a CDMA channel, several new multiuser detectors have previously proposed. In the present paper, the authors propose both a simple linear scheme for interference cancellation, which exhibits good performance, and a synchronism scheme based on the extended Kalman filter (EKF) to achieve synchronization among the different users at the base station, for a direct-sequence code-division multiple-access (DS/CDMA) synchronous system. The influence of the synchronism scheme on the performance of the interference canceller is analyzed under Rayleigh multipath fading.Peer ReviewedPostprint (published version
Fast Decoder for Overloaded Uniquely Decodable Synchronous Optical CDMA
In this paper, we propose a fast decoder algorithm for uniquely decodable
(errorless) code sets for overloaded synchronous optical code-division
multiple-access (O-CDMA) systems. The proposed decoder is designed in a such a
way that the users can uniquely recover the information bits with a very simple
decoder, which uses only a few comparisons. Compared to maximum-likelihood (ML)
decoder, which has a high computational complexity for even moderate code
lengths, the proposed decoder has much lower computational complexity.
Simulation results in terms of bit error rate (BER) demonstrate that the
performance of the proposed decoder for a given BER requires only 1-2 dB higher
signal-to-noise ratio (SNR) than the ML decoder.Comment: arXiv admin note: substantial text overlap with arXiv:1806.0395
Blind multi-user combining at the base station for asynchronous CDMA systems
This paper studies the potential benefits of antenna arrays in cellular CDMA communications and proposes a powerful scheme to undertake the array processing at the base station in CDMA mobile systems. The proposed technique exploits the temporal structure of CDMA signals. The necessary information is extracted directly from the received signals, thus no training signal orPeer ReviewedPostprint (published version
Performance Analysis of Iterative Channel Estimation and Multiuser Detection in Multipath DS-CDMA Channels
This paper examines the performance of decision feedback based iterative
channel estimation and multiuser detection in channel coded aperiodic DS-CDMA
systems operating over multipath fading channels. First, explicit expressions
describing the performance of channel estimation and parallel interference
cancellation based multiuser detection are developed. These results are then
combined to characterize the evolution of the performance of a system that
iterates among channel estimation, multiuser detection and channel decoding.
Sufficient conditions for convergence of this system to a unique fixed point
are developed.Comment: To appear in the IEEE Transactions on Signal Processin
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