scholarly journals Efisiensi Daya Protokol Quantize and Forward Pada Sistem Komunikasi Kooperatif Multi-relay

2017 ◽  
Vol 13 (1) ◽  
pp. 57
Author(s):  
Nasaruddin Nasaruddin ◽  
Rony Kurnia ◽  
Ramzi Adriman
Keyword(s):  
Cooperative Communication ◽  
Communication System ◽  
Power Efficiency ◽  
High Performance ◽  
Wireless Channel ◽  
Amplify And Forward ◽  
Distance Ratio ◽  
Diversity Techniques ◽  
System A ◽  
Single Relay

One of effective diversity techniques to combat fading on wireless channel is a cooperative communication system in which a source sends information through several relays and then forward it to a destination. A cooperative communication system has shown increased the system performance and reduced the energy consumption. However, it depends on the used relay mechanism that is relay protocols such as quantize and forward (QF) and amplify and forward (AF). In the previous research, energy efficiency of AF relay has investigated for a single-relay cooperative system, but multi-relay is more practical. Therefore, this research focuses on power efficiency in multi-relay cooperative communication system using QF protocol. The research method used is mathematical analysis and computer simulation for outage probability and power efficiency in the multi-relay QF. Simulation result found that multi-relay QF system could provide a high power efficiency, but the efficiency is reduced when the distance ratio increases. Power efficiency can be increased by adding the number of relays in the system. A comparison of power efficiency for QF and AF protocols has simulated, in which power efficiency of multi-relay QF is higher than that of multi-relay AF at distance ratio and power transmit. Thus, multi-relay QF system can provide high performance and power efficiency in the cooperative communication system.

Efficient Space-Time Two Dimensional RAKE Receiver in Asynchronous Cooperative Communications Systems with Full Diversity

2014 ◽  
Vol 536-537 ◽  
pp. 719-725
Author(s):  
Dong Wu Li ◽  
Chang Xing Pei ◽  
Yun Liang Meng
Keyword(s):  
Cooperative Communication ◽  
Communication System ◽  
Cooperative Communications ◽  
High Performance ◽  
Rake Receiver ◽  
Space Time ◽  
Two Dimensional ◽  
Combination Rules ◽  
Performance Space ◽  
Full Diversity

A high-performance space-time two dimensional RAKE receiving algorithm was proposed in asynchronous cooperative communication system. the transmitting signals were estimated coarsely by traditional space-time rake receiver, then on the basis of that we introduce feedback technology, each multipath signal of transmitted signals was composed by the decision results, and then every multipath component in the received signal can be obtained by eliminating the composed multipath signals from the received signal. Finally, the multipath components were combined by space-time combination and multipath combination rules accordingly, so spatial as well as multipath diversities were achieved. Simulation results show that the new scheme can reduce the bit error rate dramatically compare with traditional space-time RAKE in asynchronous cooperative communication system.

Single and Double-Differential Coding in Cooperative Communications

2010 ◽  
pp. 321-351 ◽  
Author(s):  
Manav R. Bhatnagar ◽  
Are Hjørungnes
Keyword(s):  
Cooperative Communication ◽  
Communication System ◽  
Cooperative Communications ◽  
Base Station ◽  
Amplify And Forward ◽  
Decode And Forward ◽  
Probability Of Error ◽  
Active User ◽  
Downlink Channels ◽  
Differential Coding

In this chapter, we discuss single and double-differential coding for a two-user cooperative communication system. The single-differential coding is important for the cooperative systems as the data at the destination/relaying node can be decoded without knowing the channel gains. The double-differential modulation is useful as it avoids the need of estimating the channel and carrier offsets for the decoding of the data. We explain single-differential coding for a cooperative system with one relay utilizing orthogonal transmissions with respect to the source. Next, we explain two single-differential relaying strategies: active user strategy (AUS) and passive users relaying strategy (PURS), which could be used by the base-station to transmit data of two users over downlink channels in the two-user cooperative communication network with decode-and-forward protocol. The AUS and PURS follow an improved time schedule in order to increase the data rate. A probability of error based approach is also discussed, which can be used to reduce the erroneous relaying of data by the regenerative relay. In addition, we also discuss how to implement double-differential (DD) modulation for decode-and-forward and amplify-and-forward based cooperative communication system with single source-destination pair and a single relay. The DD based systems work very well in the presence of random carrier offsets without any channel and carrier offset knowledge at the receivers, where the single differential cooperative scheme breaks down. It is further shown that optimized power distributions can be used to improve the performance of the DD system.

Directional AF Cooperative Communication System Based on Outage Probability

2017 ◽  
Vol 13 (2) ◽  
pp. 55-68 ◽  
Author(s):  
Ruilian Tan ◽  
Zhe Li ◽  
Peng Bai ◽  
Kai Shi ◽  
Baoxiang Ren ◽  
...  
Keyword(s):  
Lower Bound ◽  
Outage Probability ◽  
Cooperative Communication ◽  
Communication System ◽  
Signal To Noise Ratio ◽  
Directional Antenna ◽  
Channel Coefficient ◽  
Traditional Mode ◽  
Limited Power ◽  
Single Relay

In order to improve outage property of cooperative communication system, directional antenna technology could be introduced. The paper proposes single relay AF cooperative communication protocol based on directional antenna and deduces the outage probability of system in fully directional mode theoretically so as to deduce the lower bound. With the minimum system outage probability to be the target, the paper analyzes OPA (Optimum Power Allocation) and makes detailed analysis and comparison of the system property of the established model by combining with specific simulation value. The simulation result shows that on the condition of high SNR (Signal to Noise Ratio) or greater difference of channel coefficient between two terminals and relay, the lower bound and accurate value are approximated and the outage property of fully directional cooperative communication is superior to that of traditional mode. Under the situation of limited power, OPA can enhance the outage property of system effectively.

An Interference Cancellation Space-Time RAKE Receiver in Asynchronous Cooperative Communications Systems

2014 ◽  
Vol 644-650 ◽  
pp. 4152-4156
Author(s):  
Dong Wu Li ◽  
Chang Xing Pei ◽  
Yun Liang Meng
Keyword(s):  
Cooperative Communication ◽  
Communication System ◽  
Interference Cancellation ◽  
Cooperative Communications ◽  
High Performance ◽  
Rake Receiver ◽  
Multipath Fading ◽  
Spatial Diversity ◽  
Space Time ◽  
Multipath Signal

Space-time two dimensional RAKE receiver was introduced into asynchronous and cooperative communication system, and a high-performance RAKE receiving algorithm was proposed. In this algorithm, the transmitting signals were estimated coarsely by traditional space-time rake receiver, then each multipath signal was reconstructed using the estimated result as well as the channel impulse response, and then eliminated successively from reception signals, so it can eliminate Inter Symbol Interference of receiver signals which generate by multipath fading, and the line of sight (LOS) component in the received signal was obtained, and finally, the space-time combination was carried out to the LOS component, and the spatial diversity was achieved. This algorithm can effectively reduce the bit error rate of the asynchronous cooperative communication system. Simulation result shows that the new algorithm can improve the performance of traditional space-time RAKE when SNR is higher than 5dB dramatically.

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.

Research on Overlapped Time Division Multiplexing in the Amplify-and-Forward Cooperative Mode

2015 ◽  
Vol 713-715 ◽  
pp. 1103-1106
Author(s):  
Hong Zhang ◽  
Wei Ping Ma
Keyword(s):  
Cooperative Communication ◽  
Gaussian Noise ◽  
Communication System ◽  
Additive White Gaussian Noise ◽  
Spectrum Efficiency ◽  
Amplify And Forward ◽  
Time Division Multiplexing ◽  
Simulation Results ◽  
Time Division ◽  
New System

In order to improve spectrum efficiency of cooperative communication system, Overlapped Time Division Multiplexing (OVTDM) is applied to Amplify-and-Forward (AF) cooperative communication system. The simulation results under Additive White Gaussian Noise (AWGN) channel show that the performance of new system is superior to that of corresponding AF cooperative communication system.

scholarly journals Bit Error Rate Performance Analysis of a Multiple Amplify and Forward Relaying Aided Cooperative MIMO-OFDM System

2020 ◽  
Vol 9 (3) ◽  
pp. 2355-2359
Keyword(s):  
Wireless Network ◽  
Cooperative Communication ◽  
Orthogonal Frequency Division Multiplexing ◽  
Amplify And Forward ◽  
Cooperative Mimo ◽  
Minimum Mean Squared Error ◽  
Mimo Ofdm ◽  
Multiple Relays ◽  
Multiple Relay ◽  
Single Relay

In wireless systems the orthogonal frequency division multiplexing (OFDM) is one of the most influential means of transmission techniques. Data channel having higher speed are converted into some parallel channels by OFDM. For better performance of wireless network, cooperative communication using multiple relay is widely used. Substantial improvement can be achieved in case of reliability and throughput for wireless network if multiple relays are implemented between the source and destination by developing cooperative communication with multiple input multiple output (MIMO) OFDM. A mathematical model has been developed based on amplify and forward (AF) multiple relay for the system of cooperative MIMO-OFDM. Along with the detection system based on minimum mean squared error, the cooperative MIMO-OFDM, with multiple relays, can provide better performance than transmission system using single relay, which can be found from analyzing simulation. A considerable amount of deterioration was also noticed in the color image with changing the number of relays. Signal salvation is better for multiple relay than single relay.

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