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...

This paper concerns two-hop communication over relay-assisted Block fading channel. It is assumed there is not a direct link between the transmitter and the affiliated destination and the communication occurs in two hops through the use of a relay, where the amplify and forward (AF) strategy is employed at this node. In this case, in a Rayleigh block fading channel, the optimal weight function ...

The paper studies the capacity of the OFDM and the OFDMA relay networks. Two relay schemes, amplify-and-forward (AF) relay and decode-and-forward (DF) relay are analyzed and compared for both OFDM and OFDMA relay networks. A relay node selection algorithm is proposed for OFDMA relay network. Numerical results show that under small relay power transmission, AF outperforms DF while the opposite i...

647 Abstract— In this letter, non-regenerative Amplify-and-Forward (AF) relay systems based on half and full duplex schemes are investigated and their performance is analyzed and compared in terms of outage probability. Although the AF relay systems have been widely investigated in many previous literatures, most of them adopted a half duplex scheme due to hardware limitation and mathematical t...

The problem of soft information optimization for memoryless relay networks is motivated and studied through AF relay networks, and in particular the AF relay multiple access (MAC) and broadcast (BC) channels. Relay optimization, capacity region characterization and optimal scheduling are addressed.

We consider multi-hop multiple access (MAC) and broadcast channels (BC) where communication takes place with the assistance of relays that amplify and forward (AF) their received signals. For a two hop parallel AF relay MAC, assuming a sum power constraint across all relays we characterize optimal relay amplification factors and the resulting capacity regions. We find the sum rate capacity and ...

In this letter, we propose an efficient relay antenna selection algorithm for the amplify and forward (AF) two-way multipleinput multiple-output (MIMO) relay systems with analogue network coding (ANC). The proposed algorithm greedily selects the additional receivetransmit antenna pair that provides the maximum sum-rate. An iterative computation method is also designed to evaluate the sum-rate e...

Relay based cooperative spectrum sensing elevates the spectrum sensing problems in harsh propagation conditions if the relay nodes are positioned suitably for the dynamic spectrum access systems. This article investigates the performance of relay based spectrum sensing (energy detection based) in myriad fading environments using the area under the receiver operating characteristic curve (AUC) p...

In this paper, the sub-optimal power allocation relay selection (SBS-AF) algorithm in multiple-input multiple-output (MIMO) relay networks was proposed. The energy efficiency and the symbol error rate (SER) in multiple antennas MIMO relay networks is investigated. Amplify andforward (AF) relay scheme, where N relay access point(s) occupied with Q antennas cooperatively forwards packets to the d...

This paper concerns power allocation in relay-assisted wireless channels for two-hop transmission. First, the transmitter sends the information to both the relay and receiver parts. Next, in the second hop, the transmitter cooperates with the relay to increase the received signal to noise ratio (SNR), assuming the relay makes use of the Amplify and Forward (AF) strategy. Moreover, it is assumed...