List-Based Group-Wise Symbol Detection for Multiple Signal Communications

Abstract

Co-channel interference (CCI) occurs in a wireless receiver when multiple signals are present. The receiver experiences excessive CCI under overload which occurs when there are more signals than receive antennas. This makes separation and estimation of the transmitted data signals difficult. We develop a novel reduced-complexity receiver structure for the separation and symbol detection of multiple co-channel signals in frequencyflat Rayleigh fading channels. Moreover, we show that list-based group-wise processing can achieve better performance at low and moderate signal-to-noise ratios than existing group-wise soft information processing schemes. The receiver is equipped with multiple antennas and developed to work under overload. Its structure consists of a linear preprocessor followed by a nonlinear reduced-complexity symbol detector. The proposed list group-search detection (LGSD) algorithm relies on list feedback and reduces complexity by iteratively searching over groups of transmitted symbols. It outputs a list of likely data symbols which is well suited to further processing using soft input error control decoders. Simulation shows that LGSD can achieve near optimum joint maximum likelihood performance under overload at significantly lower complexity.

Reduced complexity satellite broadcast receiver with interference mitigation in correlated noise

“…Based on this truncation, we improve the performance of the E‐LGSD and propose RC‐LGSD receiver. We carry out extensive Monte Carlo simulations to investigate the performance of the proposed receiver in realistic scenarios. Our simulations show that RC‐LGSD can outperform the conventional LGSD, while having a lower complexity than E‐LGSD . Moreover, we perform an in‐depth numerical investigation on the impact of various algorithm parameters and the interesting trade‐off between performance and complexity.…”

“…It is important to note that the conventional LGSD and the 2 proposed techniques, E‐LGSD and RC‐LGSD, utilize the same receiver structure shown in Figure , albeit with the linear preprocessor designed differently in each case. In the conventional LGSD, the linear preprocessor (beamformer and the noise whitening filter) is based on the assumptions that the interference is a white Gaussian process and that the observation noise is uncorrelated.…”

“…In the following subsections, we design W and F for E‐LGSD before we truncate F to obtain T for RC‐LGSD. Beamforming: The conventional LGSD uses an SNR‐based (MRC) beamformer. However, in satellite systems the structure of the interference can be exploited to design an SINR‐based beamformer that can further enhance the receiver performance.…”

“…For nonsatellite scenarios, cochannel interference cancellation techniques for overloaded receivers are discussed in other studies . These works are generally based on the maximum‐likelihood approach or a lower complexity variation of it.…”

Multiuser detection of overloaded systems employing HARQ

“…However, there is an exponential growth in com plexity with the number of transmit antennas, making it less feasible for practical applications. To overcome this limitation, reduced-complexity MUD algorithms have been developed for overloaded scenarios [4], [5], [6]. These algorithms demand sophisticated implementation and still have quite high com putational complexity.…”