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In cooperative communication networks, the use of multiple relays between the source and the destination was proposed to increase the diversity gain. Since the source and all the relays must transmit on orthogonal channels, multiple relay cooperation is considered inefficient in terms of channel resources and bandwidth utilization. To overcome this problem, the concept of best relay selection was...
In this paper, compressive sampling (CS) based energy detectors are developed for sparse communication signals, namely, pulse-position modulation (PPM) and frequency shift-keying (FSK) signals so as to reduce the complexity and sampling rate at the receiver. We focus on noncoherent detection, thereby avoiding the channel estimation step. Exact bit error probability (BEP) expressions for receivers...
In this paper, we analyze the ergodic capacity (per unit bandwidth) and Average symbol error probability (ASEP) of an incremental relaying protocol used in conjunction with opportunistic relaying and consider a non-regenerative wireless relay network with Rayleigh fading channels. We consider a selection combining technique at the destination in order to combine the two signals, one from the direct...
Stochastic signaling is investigated under second and fourth moment constraints for the detection of scalar-valued binary signals in additive noise channels. Sufficient conditions are derived to determine when the use of stochastic signals instead of deterministic ones can or cannot enhance the error performance of a given binary communications system. Also, a convex relaxation approach is employed...
This paper addresses the problem of transmit beamforming (BF) design for cyclic prefixed transmissions over MISO frequency selective channels. Unlike [1] which is based on convex optimization tools, we here give two more computationally effective solutions in close-form to minimize the arithmetic mean of the effective error probabilities (ARITH-EEP) under the per-antenna power constraint (PPC). Moreover,...
Computing the log likelihood ratios (LLR's) of the transmitted bits in a multiple-input multiple-output (MIMO) system is an NP hard problem. Many suboptimal soft MIMO detectors have been proposed to reduce the detection complexity. The state-of-the art tries to combine the search for the maximum a posteriori (MAP) estimate and the counter-hypotheses in a single tree pass. However, not all possible...
We propose two practical schemes for the cancellation of nonlinear distortions caused by the power amplifiers (PA) in Orthogonal Frequency Division Multiplexing (OFDM) systems. The algorithms are iterative and located at the receiver. They utilize a soft channel decoder to improve the capabilities of the distortion estimation and relay all the computational complexity to the receiver. Simulation results...
The aim of this paper is to show the improvement of Transmitted-Reference (TR) communication systems when an antenna array is used at the receiver side. A generalized model of communication waveforms is involved so that this study is valid for any kind of carrier waveforms, as well as sinusoidal signals as in conventional narrowband communications, UWB impulses or even chaotic waveforms. Thus a BER...
In this paper we investigate the performance of proactive opportunistic relaying with amplify-and-forward (AF) protocol over independent and non-identically distributed Generalized Gamma fading channels. The Generalized Gamma distribution is very versatile and accurately approximates many of the commonly used channel scenarios for multipath, shadow and composite fading. We show that opportunistic...
Bit-interleaved coded modulation with iterative decoding (BICM-ID) performs well under a variety of channel conditions. Based on a factor graph representation of BICM-ID, we propose a modification of the BICM-ID receiver that can reduce the computational complexity significantly without BER degredation. The basic idea is to avoid updates of code bit log-likelihood ratios whose magnitude is already...
In mobile OFDM systems, such as underwater acoustic and digital video broadcasting (DVB) systems, time variation causes severe inter-carrier interference (ICI) which limits data detection performance. To address this problem, a signal processing strategy using several partial-interval FFTs instead of a conventional full-interval single FFT is proposed. Weighted combining of the partial FFT outputs...
In previous works on two-relay two-hop asynchronous cooperative networks we showed that, based on outage probability derivation, sending the same information frame by the two relays with a relative delay ensures a diversity order of two. In this paper, we propose a new practical asynchronous distributed coding scheme. This code performs a combination of the symbols with constellation rotation and...
In this paper, an adaptive space-time receiver for cooperative relay networks is proposed. Using cooperative amplify-and-forward relay nodes, it is possible to increasing the rank of the multiple-input multiple-output (MIMO) channel. The proposed receiver is based on a joint adaptive iterative detection and decoding algorithm, adaptively cancels co-channel interference and eliminates the multiple...
This paper deals with an adaptive equalizer based on Laguerre lattice filter and the recursive least square (RLS) adaptive algorithm for direct sequence-code division multiple access (DS-CDMA) communication system. Intersymbol interference (ISI) arises due to multipath propagation, which destroys the code orthogonality, gives rise to multiple access interference(MAI). Therefore, the objective of this...
This paper presents and discusses the performance of maximum ratio combining (MRC) scheme in the presence of intersymbol interference (ISI) caused by cochannel interference (CCI) in flat Rayleigh fading environments. The probability of error is estimated using the Gaussian Quadrature Rule (GQR) based on the moment method, which can provide results with high degree of accuracy and efficiency compared...
The maximum likelihood (ML) detection is the optimal detection method for multiple-input multiple-output (MIMO) communication systems. The normal K-best sphere decoding algorithm (SDA) can guarantee a fixed throughput, but it induces a large bit error rate (BER) degradation. In order to achieve close-to-ML performance, the K value needs to be sufficiently large. Thus, it needs large computation with...
The exact performance analysis of MMSE (minimum-mean-square-error) combining for space diversity reception is studied in the presence of a single and multiple cochannel interference (CCI) sources, and compared to maximum-ratio combining (MRC). This paper considers digital cellular mobile radio systems with quadrature amplitude modulation (QAM) transmission and two diversity antennas in flat and quasi-static...
In this paper, we present a multistage group-decision-aid MUD (MG-MUD) for the uplink multirate code division multiple access (CDMA) systems. To provide good tradeoff between the performance and computational complexity, the new MUD is based on the widely MMSE criterion and constructed by a bank of group detectors in each stage. First, the users are classified into different groups according to their...
Phase noise causes common phase error (CPE) and intercarrier interference (ICI) in orthogonal frequency division multiplexing (OFDM) system. To mitigate the effects of phase noise, many schemes have been proposed, but they are either computationally complex or at the price of sacrificing spectral efficiency. In this paper, a continuous Hopfield neural network (HNN) is designed for OFDM signal receiver...
The multi-band orthogonal frequency division multiplexing (MB-OFDM) is an ultra wideband (UWB) technology that can transmit information at the maximum data rate of 480 Mb/s. When the simultaneous operating piconets (SOP) are located closely, the symbol collisions are expected to occur among the symbols transmitted over the same sub-band at the same time. This interference will decrease throughputs...
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