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.

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.

scholarly journals Deep Learning Network for Multiuser Detection in Satellite Mobile Communication System

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Guan Qing yang ◽  
Wu Shuang ◽  
He Ya-Ru
Keyword(s):  
Deep Learning ◽  
Multiuser Detection ◽  
Mobile Communication ◽  
Communication System ◽  
Interference Cancellation ◽  
Multipath Fading ◽  
Mobile Communication System ◽  
Multipath Fading Channel ◽  
Learning Network ◽  
Deep Learning Network

A multiuser detection (MUD) algorithm based on deep learning network is proposed for the satellite mobile communication system. Due to relative motion between the satellite and users, multiple access interference (MUI) introduced by multipath fading channel reduces system performance. The proposed MUD algorithm based on deep learning network firstly establishes the CINR optimal loss function according to the multiuser access mode and then obtains the best multiuser detection weight through the steepest gradient iteration. Multilayer nonlinear learning obtains interference cancellation sharing weights to achieve maximum signal-to-noise ratio through gradient iteration, which is superior than the traditional serial interference cancellation algorithm and parallel interference cancellation algorithm. Then, the weights with multiuser detection through multilayer network forward learning iteration are obtained with traditional multiuser detecting quality characteristics. The proposed multiuser access detection based on deep learning network algorithm improves the MUD accuracy and reduces the number of traditional multiusers. The performance of the satellite multifading uplink system shows that the proposed deep learning network can provide high precision and better iteration times.

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.

scholarly journals A New Combination of RAKE Receiver and Adaptive Antenna Array Beamformer for Multiuser Detection in WCDMA Systems

2011 ◽  
Vol 2011 ◽  
pp. 1-9
Author(s):  
Shahriar Shirvani-Moghaddam ◽  
Hajar Sadeghi
Keyword(s):  
Multiuser Detection ◽  
Smart Antenna ◽  
Rake Receiver ◽  
Multipath Fading ◽  
Spatial Diversity ◽  
Recursive Least Squares ◽  
New Combination ◽  
Adaptive Antenna ◽  
Blind Beamforming ◽  
Code Division Multiple

The aim of this paper is to combine smart antenna beamforming and RAKE receiver in wideband code division multiple access (WCDMA). The proposed method combines spatial diversity as well as temporal diversity to improve the performance and overcome both interferences and multipath fading. This investigation has focused on one of the new proposed blind beamforming algorithms. It is based on constrained constant modulus (CCM) algorithm which is used for deriving a recursive-least-squares (RLS-) type optimization algorithm. We illustrate the comparison of bit error rate (BER) of the proposed receiver with simple correlator and also 1D-RAKE receiver in multiuser detection (MUD) WCDMA. The simulation results show that the proposed 2D-RAKE receiver offers lower BER rather than conventional ones, that is, it is an effective solution for decreasing the effect of interference and increasing the capacity, in a joint state.

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