Abstract The multiple-access interference (MAI) limits the performance of the DS-CDMA uplink transmission. 2D OVSF spread/chip-interleaved DS-CDMA is an MAI-free system, and hence single-user coherent frequency-domain equalization (FDE) can be used instead of complicated multiuser detection (MUD). However, coherent FDE needs channel estimation. Pilot-assisted channel estimation is not reliable ...

In multiple-access communication systems co-channel interference can be mitigated by applying multiuser detection instead of treating the interference as additive noise [1]. In this paper we focus on downlink operation in a GSM-like TDMA network and investigate multiuser channel estimation and data symbol detection of two users that share the same physical channel in two adjacent cells. Such a ...

In this paper, the uplink multiuser code division multiple access (CDMA) communication system model is described in the form of space-time domain through antenna array and multipath fading expression. Novel suitable neural network technique is proposed as an effective signal processing method for the receiver of such an uplink multiuser CDMA system. By the appropriate choice of the channel stat...

Multiuser underwater acoustic communication is one of the enabling technologies for the autonomous ocean-sampling network (AOSN). Multiuser communication allows vehicles, moorings, and bottom instruments to interact without human intervention to perform adaptive sampling tasks. In addition, multiuser communication may be used to send data from many autonomous users to one buoy with RF communica...

ii i Direct-Sequence Code Division Multiple-Access (DS/CDMA) has for some years been considered as a candidate for future personal and mobile communications. The reasons are mainly the properties of universal frequency reuse and the multipath mitigation. Generally, the focus has been on low rate services such as speech, and very little has been done on evaluating the performance for a system th...

In this paper a soft-in soft-output (SISO) multiuser detection algorithm for synchronous direct sequence-code division multiple access (DS-CDMA) systems operating over a slow Rayleigh fading channel is illustrated. Its derivation is based on the Bayesian Expectation Maximization (BEM) technique. The proposed detector estimates the fading channel in an iterative fashion and produces the a poster...

A novel iterative receiver is proposed for relay-assisted multiuser communications in which multiple users transmit to a destination with the help of a relay and using fast frequency-hopping modulation. Each user employs a channel encoder to protect its information and facilitate interference cancellation at the receiver. The signal received at the relay is either amplified, or partially decode...

We propose a new framework for multiuser detection in fast-fading channels that are encountered in many mobile communication scenarios. Existing multiuser RAKE receivers, developed to combat multipath fading and multiuser interference in slow fading, suffer substantial degradation in performance under fast fading due to errors in channel state estimation. The detectors proposed in this paper em...

This paper investigates the problem of dynamic multiuser subchannel allocation in the downlink of OFDM systems. The assumptions are that the channel model is quasi-static and that the base station has perfect channel information. In traditional TDMA or FDMA systems, resource allocation for each user is nonadaptively fixed, and the water-filling power spectrum is known to be optimal. Since the s...

This paper describes power-controlled multi carrier and multiuser detection techniques for Code Division Multiple Access (CDMA) systems. In conventional CDMA systems, a RAKE receiver is employed to overcome wireless channel effect due to frequency selective characteristics of wireless CDMA systems. Alternatively, multi carrier technique can also be used to overcome the effect of frequency selec...