The multiuser separation problem in a multi-input multioutput (MIMO) orthogonal frequency division multiplexing (OFDM) system can be represented as an instantaneous blind source separation (BSS) problem in complex domain. But reconstruction of multiuser signals suffers from permutation indeterminacy, amplitude scaling ambiguity and phase distortion which are inherent to complex BSS. This paper ...

This paper presents a multiuser maximum a posteriori (MAP) decoder for synchronous code division multiple access (CDMA) signals on Rayleigh at-fading channels. The receiver does not assume perfect channel information at the receiver. The key idea is to expand the decoding trellis for the purpose of joint channel estimation and decoding. The time varying channel eeect is equalized by coupling mi...

We present a framework for analyzing multiuser detectors in the context of statistical mechanics. A multiuser detector is shown to be equivalent to a conditional mean estimator which finds the mean value of the stochastic output of a so-called Bayes retrochannel. The Bayes retrochannel is equivalent to a spin glass in the sense that the distribution of its stochastic output conditioned on the r...

Reliable estimation of users’ channels and data in rapidly time varying fading environments is a very challenging task of multiuser detection (MUD) techniques that promise impressive capacity gains for interference limited systems such as non-orthogonal CDMA and spatial multiplexing MIMO based LTE. This paper analyzes relative channel estimation error performances of conventional single user an...

An iterative multiuser detection scheme is proposed for DS-CDMA system. An iterative multiuser detection has a partial parallel interference cancellation (PIC) detector and serially concatenated codes. Taking the expectation value of a coded bit the partial PIC detector produces a metric, which becomes an input to the decoders. It is shown that the proposed iterative multiuser detector has near...

The problem of joint source–channel and multiuser decoding for code division multiple access channels is considered. The block source–channel encoder is defined by a vector quantiser (VQ). The jointly optimum solution to such a problem has been considered before, but its extremely high complexity makes it impractical for systems with medium to large number of users and/or medium to large size o...

A multistep linear prediction approach is presented for blind channel estimation, multiuser interference (MUI) suppression, and detection of asynchronous short-code direct sequence code division multiple access signals in multipath channels. Only the spreading code of the desired user is assumed to be known; its transmission delay may be unknown. We exploit the recently proposed multistep linea...