scholarly journals Power Optimized Single Relay Selection with an Improved Link-Adaptive-Regenerative Protocol

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Jie Li ◽  
Jianrong Bao ◽  
Shenji Luan ◽  
Bin Jiang ◽  
Chao Liu
Keyword(s):  
Outage Probability ◽  
Cooperative Communications ◽  
Power Efficiency ◽  
Relay Selection ◽  
Relay Node ◽  
Link Quality ◽  
Selection Strategy ◽  
Amplify And Forward ◽  
Selection Scheme ◽  
Single Relay

To improve the reliability and efficiency in cooperative communications, a power optimized single relay selection scheme is proposed by increasing the diversity effort with an improved link-adaptive-regenerative (ILAR) protocol. The protocol determines the forwarding power of a relay node by comparing the signal-to-noise ratio (SNR) at both sides of the node; thus it improves the power efficiency. Moreover, it also proposes a single relay selection strategy to maximize the instantaneous SNR product, which ensures the approximate best channel link quality for good relay forwarding. And the system adjusts the forwarding power in real time and also selects the best relay node participated in the cooperative forwarding. In addition, the cooperation in the protocol is analyzed and the approximate expression of the bit-error-rate (BER) and the outage probability at high SNRs are also derived. Simulation results indicate that the BER and outage probability of the relay selection scheme by the ILAR protocol outperform other contrast schemes of current existing protocols. At BER of 10−2, the proposed scheme with ILAR protocol outperforms those of the decoded-and-forward (DF), the selected DF (SDF), and the amplify-and-forward (AF) protocols by 3.5, 3.5 and 7 dB, respectively. Moreover, the outage probability of the relay system decreases with the growth of the relay number. Therefore, the proposed relay selection scheme with ILAR strategies can be properly used in cooperative communications for good reliability and high power efficiency.

scholarly journals Full-Duplex Mode in Amplify-and-Forward Relay Channels: Outage Probability and Ergodic Capacity

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Rongyi Hu ◽  
Chunjing Hu ◽  
Jiamo Jiang ◽  
Xinqian Xie ◽  
Lei Song
Keyword(s):  
Outage Probability ◽  
Relay Node ◽  
Ergodic Capacity ◽  
Full Duplex ◽  
Relay Channels ◽  
Amplify And Forward ◽  
Half Duplex ◽  
Single Relay ◽  
Close Form ◽  
Loop Interference

This paper investigates the outage probability and ergodic capacity performances for full-duplex mode in two-way amplify-and-forward relay channels. The two-way relay channels which consist of two source nodes and a single relay node working in full-duplex mode, are assumed as independent and identically distributed as Rayleigh fading. The self-interference or loop interference of the relay is unavoidably investigated for full-duplex mode. And the close-form expressions for the outage probability and ergodic capacity of full-duplex mode are derived, considering both loop interference and the coefficients of two-way relay amplify-and-forward channels. To further facilitate the performance of full-duplex mode, the half-duplex modes over different transmission time slots are analyzed. Simulation results point out the effect of loop interference on outage probability and ergodic capacity of two-way amplify-and-forward relay channels with full-duplex mode and show that full-duplex mode can achieve better performance in terms of capacity and even outperform half-duplex modes in the presence of loop interference.

scholarly journals Adaptive Relay Selection Scheme Based on Bayesian Inference (AS-BI) for Cooperative Communication in 5G Networks

TEM Journal ◽  
2021 ◽  
pp. 839-846
Author(s):  
Madeeha Ishtiaq ◽  
Shakeel A. Waqas ◽  
Muhammad Saifullah ◽  
Nazih K. Mallat
Keyword(s):  
Bayesian Inference ◽  
Relay Selection ◽  
Network Performance ◽  
Optimal Solution ◽  
Relay Node ◽  
Cooperative Networks ◽  
5G Networks ◽  
Amplify And Forward ◽  
Selection Scheme ◽  
Adaptive Selection

In this paper, a Bayesian inference-based relay selection scheme, also called Adaptive Selection on Bayesian Inference (AS-BI) for cooperative networks in 5G networks is invoked. This scheme works on the principle of Amplify-and-Forward (AF) protocol which selects the most optimal relay towards the destination. This paper proposed a probabilitybased relay selection scheme in which posterior probability is calculated for the selection of relay node based on the prior and conditional probabilities. The proposed scheme has been accepted as optimal solution for relay selection, which significantly enhances the network performance by reducing (BER) for constant SNR.

scholarly journals Optimized Power Allocation and Relay Location Selection in Cooperative Relay Networks

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Jianrong Bao ◽  
Jiawen Wu ◽  
Chao Liu ◽  
Bin Jiang ◽  
Xianghong Tang
Keyword(s):  
Outage Probability ◽  
Power Allocation ◽  
Relay Selection ◽  
Relay Network ◽  
Total Power ◽  
Selection Strategy ◽  
Relay Location ◽  
Single Relay ◽  
Equal Power Allocation ◽  
Equal Power

An incremental selection hybrid decode-amplify forward (ISHDAF) scheme for the two-hop single relay systems and a relay selection strategy based on the hybrid decode-amplify-and-forward (HDAF) scheme for the multirelay systems are proposed along with an optimized power allocation for the Internet of Thing (IoT). Given total power as the constraint and outage probability as an objective function, the proposed scheme possesses good power efficiency better than the equal power allocation. By the ISHDAF scheme and HDAF relay selection strategy, an optimized power allocation for both the source and relay nodes is obtained, as well as an effective reduction of outage probability. In addition, the optimal relay location for maximizing the gain of the proposed algorithm is also investigated and designed. Simulation results show that, in both single relay and multirelay selection systems, some outage probability gains by the proposed scheme can be obtained. In the comparison of the optimized power allocation scheme with the equal power allocation one, nearly 0.1695 gains are obtained in the ISHDAF single relay network at a total power of 2 dB, and about 0.083 gains are obtained in the HDAF relay selection system with 2 relays at a total power of 2 dB.

scholarly journals Analysis of Packet Diversity in Buffer-Aided Relaying over Symmetric and Asymmetric Rayleigh Fading Channels

Symmetry ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 241 ◽  
Author(s):  
Hina Nasir ◽  
Nadeem Javaid ◽  
Waseem Raza ◽  
Muhammad Shafiq
Keyword(s):  
Outage Probability ◽  
Fading Channels ◽  
Relay Selection ◽  
Signal To Noise Ratio ◽  
Packet Delay ◽  
Cooperative Relaying ◽  
Link Quality ◽  
Relay Channel ◽  
Amplify And Forward ◽  
Active Channels

In this paper, we propose innovative schemes for relay selection that jointly explore packet selection and relay selection for buffer-aided amplify and forward (AF) cooperative relaying networks. The first proposed scheme chooses the most suitable channel based on link quality from all active channels, i.e., channels with neither empty nor full corresponding buffers. In the second proposed scheme, the most suitable channel is chosen based on buffer status. When the source-relay channel is determined, the corresponding relay collects data in the buffer. Likewise, when the relay-destination channel is picked, the most suitable packet is dispatched from the buffer. The most suitable packet is one that provides the highest end-to-end equivalent signal-to-noise ratio. We simulated the outage probability, average throughput and packet delay and analyzed the proposed protocol for both symmetric and asymmetric channel conditions. Comparison is made against the existing buffer-aided schemes. The results show that the proposed relay and packet selection systems help to reduce the outage probability, diversity gain and delay.

scholarly journals Performance Analysis of Secrecy Outage Probability for AF-Based Partial Relay Selection with Outdated Channel Estimates

2017 ◽  
Vol 2017 ◽  
pp. 1-8
Author(s):  
Kyu-Sung Hwang
Keyword(s):  
Outage Probability ◽  
Relay Selection ◽  
Information Source ◽  
Integral Form ◽  
Secrecy Outage Probability ◽  
Amplify And Forward ◽  
Selection Scheme ◽  
Partial Relay Selection ◽  
Channel Information ◽  
Secrecy Outage

We study the secrecy outage probability of the amplify-and-forward (AF) relaying protocol, which consists of one source, one destination, multiple relays, and multiple eavesdroppers. In this system, the aim is to transmit the confidential messages from a source to a destination via the selected relay in presence of eavesdroppers. Moreover, partial relay selection scheme is utilized for relay selection based on outdated channel state information where only neighboring channel information (source-relays) is available and passive eavesdroppers are considered where a transmitter does not have any knowledge of eavesdroppers’ channels. Specifically, we offer the exact secrecy outage probability of the proposed system in a one-integral form as well as providing the asymptotic secrecy outage probability in a closed-form. Numerical examples are given to verify our provided analytical results for different system conditions.

Performance of switching-based partial relay selection scheme for amplify-and-forward cognitive relay networks

2016 ◽  
Vol 10 (12) ◽  
pp. 1480-1492
Author(s):  
Shao-I Chu ◽  
Chih-Yuan Lien ◽  
Chien-Liang Chiu
Keyword(s):  
Relay Selection ◽  
Relay Networks ◽  
Amplify And Forward ◽  
Selection Scheme ◽  
Cognitive Relay Networks ◽  
Partial Relay Selection

Relay Selection in Distributed Transmission Based on the Golden Code Using ML and Sphere Decoding in Wireless Networks

2011 ◽  
Vol 6 (4) ◽  
pp. 63-75 ◽  
Author(s):  
L. Ge ◽  
G. J. Chen ◽  
J. A. Chambers
Keyword(s):  
Relay Selection ◽  
Cooperative Diversity ◽  
Mimo Systems ◽  
Multiple Input Multiple Output ◽  
Relay Node ◽  
Relay Network ◽  
Selection Strategy ◽  
Sphere Decoding ◽  
Golden Code ◽  
Maximum Minimum

The implementation of cooperative diversity with relays has advantages over point-to-point multiple-input multiple-output (MIMO) systems, in particular, overcoming correlated paths due to small inter-element spacing. A simple transmitter with one antenna may exploit cooperative diversity or space time coding gain through distributed relays. In this paper, similar distributed transmission is considered with the golden code, and the authors propose a new strategy for relay selection, called the maximum-mean selection policy, for distributed transmission with the full maximum-likelihood (ML) decoding and sphere decoding (SD) based on a wireless relay network. This strategy performs a channel strength tradeoff at every relay node to select the best two relays for transmission. It improves on the established one-sided selection strategy of maximum-minimum policy. Simulation results comparing the bit error rate (BER) based on different detectors and a scheme without relay selection, with the maximum-minimum and maximum-mean selection schemes confirm the performance advantage of relay selection. The proposed strategy yields the best performance of the three methods.

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