This paper derives an optimum relay position of amplify-and-forward (AF) cooperative communications with the differential transmission. As a performance benchmark, we utilize the probability of outage, which is defined as a probability that the instantaneous signal-tonoise power ratio (SNR) becomes lower than a certain threshold. The optimum relay position is found based on the theoretical expr...

In this paper, the performance of the outage probability (OP) for cognitive dual-hop relay networks with amplify-and-forward (AF) relay under spectrum sharing constraints on primary user (PU) over independent and identically distributed (i.i.d.) Nakagami-m fading channels is investigated. An exact closed-form expression for the OP of the proposed system is derived under the peak interference po...

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 consider cooperative space-frequency block-coded OFDM (SFBC-OFDM) networks with amplify-and-forward (AF) and decode-and-forward (DF) protocols at the relays. In cooperative SFBC-OFDM networks that employ DF protocol, (i), intersymbol interference (ISI) occurs at the destination due to violation of the “quasistatic” assumption because of the frequency selectivity of the relay-to-destination c...

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...

Cooperative jamming has been demonstrated to be an effective means to provide secret wireless communications and yet this is realized at the expense of the power consumption of the friendly jammers. This paper considers the scenario where friendly jammers harvest energy wirelessly from the signal transmitted by the source, and then use only the harvested energy to transmit the jamming signals f...

This paper considers a multiuser cellular two-way relay network (cTWRN) where multiple users exchange information with a base station (BS) via a relay station (RS). Each user is equipped with a single antenna, while both the BS and the RS are equipped with a very large antenna array. We investigate the performance of the cTWRN with amplify-and-forward (AF) based physical-layer network coding, a...

The new paradigm of cooperative communications is a promising resolution to carry out MIMO technique. In this thesis work, we study the performance of cooperative relay networks in which the transmission from a source to a destination is assisted by one or several relaying nodes employing amplify-and-forward (AF) and decodeand-forward (DF) protocols. The performance of two-way (or bi-directiona...

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...

Antenna correlation is generally viewed as an obstacle to realize the desired performance of a wireless system. In this article, we investigate the performance of partial relay selection in the presence of antenna correlation. We consider both channel state information (csi)-assisted and fixed gain amplify-and-forward (AF) relay schemes. The source and the destination are equipped with multiple...