The enhancement of Hopfield Neural Network (HNN) multiuser detector for Multicarrier CodeDivision Multiple-Access (MC-CDMA) signals in a multipath fading channel (MPF) is investigated. The previous design of HNN fails to remove Multiple-Access Interference (MAI) in a MPF channel because it is designed to work in a Gaussian channel. In this paper, we have designed a new HNN multiuser detector th...

A novel multiuser code division multiple access (CDMA) channel estimator based on genetic algorithm is considered which estimates the fading channel impulse response coefficients of all the users. Furthermore, the optimum multiuser detector, based on the maximum likelihood (ML) rule, is developed in order to identify the transmitted data sequence. As is demonstrated in simulation results, the p...

This paper considers an uplink multiuser hybrid beamforming system where a base station (BS) communicates with multiple users simultaneously. The performance of the uplink multiuser hybrid beamforming system depends on the effective channel which is given by the product of channel matrix and the analog beams. Therefore, to maximize the performance, we need to acquire information of the channels...

An approach to optimal soft decoding for vector quantization (VQ) over a code-division multiple-access (CDMA) channel is presented. The decoder of the system is soft in the sense that the unquantized outputs of the matched filters are utilized directly for decoding (no decisions are taken), and optimal according to the minimum mean-squared error (MMSE) criterion. The derived decoder utilizes a ...

Time reversal, that is prefiltering of transmitted signals with time reversed channel impulse responses, may be used in single user communications in order to move complexity from the receiver to the transmitter, and in multiuser communications to also modify statistical properties of multiuser interference. Imperfect channel estimation may, however, affect pre-vs. post-filtering schemes in a d...

A multiuser independent Q-learning method which does not need information interaction is proposed for multiuser dynamic spectrum accessing in cognitive radios. The method adopts self-learning paradigm, in which each CR user performs reinforcement learning only through observing individual performance reward without spending communication resource on information interaction with others. The rewa...

This paper presents algorithms and architecture designs that can meet real-time requirements of multiuser channel estimation and detection in future CDMA-based wireless base-station receivers. Sophisticated algorithms proposed to implement multiuser channel estimation and detection make their real-time implementation difficult on current Digital Signal Processor (DSP)-based receivers. A maximum...

In this work we analyze the evolution of the multiuser-efficiency for the uplink of a coded iterative CDMA receiver with channel estimation in flat Rayleigh fading channels with block fading characteristic. The receiver processing parts are: Multiuser detector implemented as PIC-LMMSE, a bank of single user MAP decoders, and a channel estimator unit which makes use of fed back soft bit values i...

A correlated diversity Rayleigh fading (CDRF) channel models inter-diversity fading and signal correlations. This paper considers the multiuser CDRF channel wherein several users transmit information simultaneously using signals with inter-diversity as well as inter-user correlations. Each user employs DPSK modulation. Besides allowing simple noncoherent detection without channel estimation alg...

Multiuser diversity is a form of diversity inherent in a wireless network, provided by independent timevarying channels across the di erent users. The diversity bene t is exploited by tracking the channel uctuations of the users and scheduling transmissions to users when their instantaneous channel quality is near the peak. The diversity gain increases with the dynamic range of the uctuations a...