Muhammad I. Khalil

Error rate analysis of AF-relay wireless networks under different SNR levels

This paper presents a new method for analyzing the Bit Error Rate (BER) performance of two-hop Amplify-and-Forward Multiple Relay (AF-MR) networks. This paper considers, a flat-fading channel and a relay selection scheme to select a relay with the highest Signal-to-Noise Ratio (SNR). The method aims to unify the BER calculation under low, high and optimal SNR levels. Asymptotic BER (ABER) performance at high SNR value is calculated first, and standard expressions for exact BER (EBER) performance at low and optimal SNRs are then derived. The analytic method depends on the conventional BER (CBER) approach of one-hop communication systems. The optimal SNR is obtained by balancing energy efficiency and spectral efficiency. The proposed method is found to be effective for calculating the BER of AF-MR network performance under any SNR conditions. Moreover, it improves the accuracy of ABER performance by reducing disparity computation errors between ABER and EBER performances and this allows the BER of AF-MR networks to be accurately calculated using either ABER or EBER. The outcome expressions for the method are validated by simulation results.

Bit error rate performance analysis in amplify-and-forward relay networks

AbstractTwo methods are proposed in this paper to estimate asymptotic and exact bit error rate (BER) in two-hop amplify-and-forward (AF) relay networks . Rayleigh-fading channels are considered and selection strategy is used to select the highest end-to-end signal-to-noise ratio relay among all relays. The first presented method unifies the BER analysis performance for both one and two hop networks in one scheme and this refers to as the unified BER (U-BER) . The second method, namely the optimal BER (O-BER), is developed to measure BER for an AF relay network that is optimized with respect to its energy and spectral efficiency. Expressions for asymptotic BER performance for (U-BER) and (O-BER) are derived. An expression for the exact BER for (U-BER) is also obtained. The proposed methods provide useful and efficient tools for analyzing the BER performance in AF relay networks . Analytical and simulated results are compared to validate the BER calculation.

Energy-efficient design for combined relay selection and power allocation AF-relay network

A wireless relay network is an effective communication scheme for energy efficient transmission. Further improvement of this scheme can be achieved by combining relay-selection and power-allocation strategies. In this paper, we consider a combined relay selection and power allocation approach under maximized output signal to noise ratio (SNR) to enhance the energy efficiency (EE) of a wireless amplify and forward relay network. With this strategy, the best relay is selected first and, then the optimal power for all nodes is allocated to optimize the EE. Simulation results show that the proposed model achieves better EE and throughput performance compared to models proposed in other studies. Further, a new model to examine the behavior between EE and spectrum efficiency (SE) has been proposed in this paper.

Energy Efficiency and Spectrum Efficiency trade-off over Optimal Relay Location in bidirectional relay networks

This paper presents a new method combines Optimal Relay Location (ORL), Energy Efficiency (EE) and Spectrum Efficiency (SE) in a bidirectional relay networks. The proposal aims to minimize power consumption with lower data rate loss. For this work, a flat fading channel is considered for exchanging signals between two wireless users separated by a specified distance. This distance is splitted by a set of bidirectional Amplify-and-Forward (AF) relay nodes that allow to amplify the input signal without any further processing. The locations of these relays are optimized first and the trade-off expression between EE and SE is then derived. All analytical expressions (i.e., optimal relay location and trade-off EE SE ) are corroborated by the simulation.

High SNR approximation for performance analysis of two-way multiple relay networks

Abstract Signal-to-Noise Ratio ( SNR ) is the key parameter in the performance evaluation of Two-Way, Amplify-and-Forward, Multiple-Relaying (TAF-MR) networks. This paper introduces new methods that use high SNR (HSNR) level approximations to analyze accurately the Bit Error Rate (BER), optimize the Relay Location (RL), and balance the energy efficiency ( EE ) and spectral efficiency ( SE ) of such networks. We consider a flat-fading channel and a strategy for selecting a relay with the highest SNR . Standardized BER expressions are obtained for a wide range of SNRs (low, high, and optimal) to yield more accurate predictions of the BER performance. Thus, by using HSNR, a unified analysis for calculating the Asymptotic BER (ABER) and the exact BER (EBER) performance is developed. The optimal SNR level is obtained by optimizing the power of network sources, which include the relay and user powers. Further, we propose a method for integrating the RL with the balancing of the EE and SE optimally to achieve the best EE improvement. The derived expressions for the methods are validated by simulation.

Energy efficiency and spectrum efficiency balance of wireless relay networks

A new method to improve Energy Efficiency (EE) in an energy-constrained wireless relay network is presented. In this network, the source nodes transmits signals through flat fading channels to a set of intermediate relay nodes which amplify signals and then forward them to the destination through other flat fading channels. The distances among source relay and destination are considered. Since the total network energy enhancement depend on the relay energy consumption which in turn depends on the users transmit powers and the geographic of relays location, the proposal method aims to optimize relay location for improving EE with the lowest sacrifice in the Spectrum Efficiency (SE). Analytical expressions for optimal relay location with balanced EE SE are derived and fully verified by simulation results.

A standard BER analysis for two-way relay networks at high and optimal SNR domains

A new method for analyzing the Asymptotic Bit Error Rate (ABER) performance of a two way Amplify-and-Forward Multiple Relay (TAF-MR) network is proposed in this paper. In this network a relay selection scheme is adopted to choose a single relay, which has the highest Signal-to-Noise-Ratio (SNR). The selected relay forwards the signal from the source to the destination through flat-fading channels. The proposed method is applied to calculate ABER at an optimal SNR domain. The optimal SNR is obtained by balancing energy efficiency and spectral efficiency schemes. The method is found to be an effective tool for analyzing bit error performance of TAF-MR networks. The analytic expression of ABER is confirmed by simulation.

Precise Error Rate Analysis of Wireless Relay Networks

A new method to analyze the bit error rate (BER) performance of two-hop multiple relay networks is presented in this paper. For this work, a flat fading channel is considered for exchanging signals between two wireless users which communicate with each other through set of bidirectional relays that operate as repeaters (amplify-and-forward). Each user adopts a relay selection scheme to choose the relay with the highest signal-to-noise-ratio (SNR). The proposed method aims to reduce the analysis of the two-hop relay network to the BER analysis of one-hop (direct link) and this allows to improve the asymptotic BER (ABER) performance of two-hop. Thereby, the ABER would be more suitable for wide SNR range. From this ABER analysis, the exact BER (EBER) can be obtained directly and this gives a standard BER analysis for bidirectional relay networks. The analytic expressions for both ABER and EBER are derived and then confirmed by simulation results. It is found that the proposal gives low disparity calculation errors between ABER and EBER. It hence provides an accurate BER analysis for a bidirectional relay networks.

Accurate error performance analysis of bidirectional amplify-and-forward relay networks

The Bit Error Rate (BER) performance of a two-hop Bidirectional Amplify-and-Forward Multiple Relay (BAF-MR) network is analyzed in two ways: the first focuses on analysing Asymptotic BER (ABER) for the applications use high Signal-to- Noise Ratio (SNR) level, and second involved Exact BER (EBER) analysis for all SNR levels. The paper also investigates a new method to increase the accuracy of the ABER for a wide range of applications work under low or high SNR levels. Moreover, the ABER is used to calculate the EBER, which is more complex than the ABER. Thus, the BER of BAF-MR networks can be evaluated under low and high SNR levels using either ABER or EBER. The analytic expressions for both ABER and EBER are confirmed by simulation.

High Energy Efficiency for Low Error Rate in Wireless Relay Networks

A new method to increase energy efficiency (EE) and decrease bit error rate (BER) in amplify-and-forward (AF) relay networks is presented in this study. In this network, the source transmitted signal through flat fading channel to a set of intermediate relay nodes which amplify and then forward the signal to the destination through a set of independent flat fading channels. The proposed EE is derived in a balanced scheme with spectral efficiency (SE), when relay nodes locations are taken into consideration. This balance between EE and SE is achieved by minimising power consumption. The BER for this balance is analysed and the relationship between BER and EE is derived. All analytical expressions are validated by numerical analysis and simulation. It is found that only a small increase in EE leads to a reduction in BER.