Recently, the idea of space-time coding has been applied to wireless relay networks wherein a set of geographically separated relay nodes cooperate to process the received signal from the source and forward them to the destination such that the signal received at the destination appears like a Space-Time Block Code (STBC). Such STBCs (referred to as Distributed SpaceTime Block Codes (DSTBCs)) w...

In this work we explicitly provide the first ever optimal, with respect to the Zheng-Tse diversity multiplexing gain (D-MG) tradeoff, cooperative diversity schemes for wireless relay networks. The schemes are based on variants of perfect space-time codes and are optimal for any number of users and all statistically symmetric (and in some cases, asymmetric) fading distributions. We deduce that, ...

This work proposes a new relay selection algorithm in an opportunistic cooperative network, which aims to establish fairness among the users. Our approach provides the same overall outage probability for users at different locations. To this end, we first define a selection region containing Amplify-and-Forward (AF) relays with a superior channel quality. Then, opportunistic relay selection fro...

This work focuses on the half-duplex (HD) relaying based on the generalized quantize-andforward (GQF) scheme in the slow fading Multiple Access Relay Channel (MARC). We consider the case that the relay has no channel state information (CSI) of the relay-to-destination link. Relay listens to the channel in the first slot of the transmission block and cooperatively transmits to the destination in...

A distributed multiuser two-way amplify-and-forward (AF) wireless relay strategy consisting of 2M sources (or 2M destinations) and N relays all equipped with single antenna per communication node is studied in this paper. All sources act as both sources and destinations with a self-interference cancelation process at the 2M destinations. The main objective is to design the closed-form of minimu...

In this letter, signal-to-noise ratio (SNR) performance is analyzed for orthogonal frequency division multiplexing (OFDM) based amplify-and-forward (AF) relay systems in the presence of carrier frequency offset (CFO) for fading channels. The SNR expression is derived under one-relay-node scenario, and is further extended to multiple-relaynode scenario. Analytical results show that the SNR is qu...

We study the performance of differential spacetime codes with linear constellation precoding (LCP) for orthogonal frequency division multiplexing (OFDM) cooperative networks over frequency selective channels. Through exploiting the unitary structure of the orthogonal STBCs, we design a low complexity differential STBC-LCP-OFDM receiver for cooperative networks. We assume the amplify-and-forward...

Relay-based cooperative systems have recently attracted significant attention since they enable exploiting the inherent spatial diversity of wireless networks with single antenna terminals. In this paper, the authors address the error performance of a cooperative diversity network consisting of a source, a destination, and multiple dual-hop amplify-and-forward (AF) relays in Rayleigh fading cha...

This paper presents an optimal solution for amplify-and-forward (AF) single-input multiple-output (SIMO) and multiple-input single-output (MISO) wireless distributed relay networks. The optimal solutions are determined based on minimum mean square error (MMSE) criterion for optimum nondiagonal and diagonal relay amplifying matrices under the transmit power constraints at the relays. The bit err...

The performance of cooperative network can be increased by using relay selection technique. Therefore, interest in relay selection is sloping upward. We proposed two new relay selection schemes based on fuzzy logic for dual hop cooperative communication. These relay selection schemes require SNR (signal to noise ratio), cooperative gain and channel gain as input fuzzy parameters for selection o...