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Error-rate performance of uplink cooperative communications with decode-and-forward protocol

IET COMMUNICATIONS 2011年第11期5卷 1484-1490页

作者： Lee, Y. Chen, Y. -N. Sou, S. -I. Natl Chi Nan Univ Grad Inst Commun Engn Puli Nantou County Taiwan Natl Cheng Kung Univ Dept Elect Engn Tainan 70101 Taiwan

For cooperative communications, the decode-and-forward (DF) protocol can give promising error-rate performance provided that the relay node has the decoding capability. In this study, the authors consider the DF cooperation for cellular uplink communications, in which the source node is equipped with a single antenna, and both the relay and destination nodes are equipped with multiple antennas. For this case, the authors analyse the exact symbol-error-rate (SER) for M-quadrature amplitude modulation (QAM) signals over Nakagami-m fading channels. To avoid the cumbersome integral calculation, the authors derive an asymptotic approximation for the SER, which lets them not only gain fast understanding of the improvement from cooperative diversity, but also have more insight into how the channel characteristics and the number of antennas affect the SER performance. Specifically, to reduce the SER, the authors find that: first, good condition of the relay-destination channels is more critical than good condition of the source-relay channels;second, large number of antennas at the relay node is more critical than large number of antennas at the destination node. All these results are not exploited and discussed before. Simulations are finally presented to demonstrate the correctness of the authors' analysis and perception for the considered cooperation scenario.

关键词： decode-and-forward protocol source-relay channels cellular radio protocols asymptotic approximation multiple antennas Modulation and coding methods Mobile radio systems cooperative communication quadrature amplitude modulation authors- analysis uplink cooperative communications single antenna source node cooperative diversity Nakagami channels destination nodes error-rate performance decode and forward communication protocols relay nodes cellular uplink communications Nakagami-m fading channels QAM M-quadrature amplitude modulation symbol-error-rate

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Performance Analysis of a Path Selection Scheme in Multi-Hop decode-and-forward protocol

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IEEE COMMUNICATIONS LETTERS 2012年第12期16卷 1980-1983页

作者： Bhatnagar, Manav R. Indian Inst Technol Delhi Dept Elect Engn IN-110016 New Delhi India

In this letter, we find cumulative distribution function (CDF) and probability density function (PDF) of the generalized max-min Exponential random variable (RV) in terms of converging power series. By using the PDF of this RV, the average bit error rate (BER) of the max-min criterion based best path(1) selection scheme in multi-hop decode-and-forward (DF) cooperative communication system over Rayleigh fading channels is analyzed. It is demonstrated by the analysis and simulation that max-min criterion based path selection works very well in the multi-hop DF cooperative system.

关键词： decode-and-forward protocol multi-hop relaying path selection Rayleigh fading

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ML Performance Analysis of the decode-and-forward protocol in Cooperative Diversity Networks

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2009年第7期8卷 3855-3867页

作者： Ju, MinChul Kim, Il-Min Queens Univ Dept Elect & Comp Engn Kingston ON Canada

We analyze the maximum-likelihood (ML) performance of the decode-and-forward protocol in a cooperative diversity network which consists of a source, a relay, and a destination with a direct path signal, but which is not equipped with cyclic-redundancy-check (CRC) codes. In this system, due to a symbol error at the relay, the ML receiver at the destination needs to consider all the possible symbol detection scenarios at the relay as well as at the destination. Therefore, the ML detection metric is given by a linear combination of exponential functions, which prevents the use of the classical minimum Euclidean distance rule. Adopting the max-log approximation, we approximate the ML detection rule which makes the ML performance analysis tractable. In order to facilitate the derivation of decision regions, we simplify the ML detection rule in the two-dimensional real space such that two metric values of two adjacent constellation points are sequentially compared. Then we obtain decision regions in a form without union and intersection. Finally, based on the decision regions, we derive a very accurate closed-form BER approximation for M-pulse amplitude modulation (PAM) and M-quadrature amplitude modulation (QAM). The obtained BER expression can serve as the error performance upper-bound of the decode-and-forward protocol in cooperative diversity networks.

关键词： Bit-error rate (BER) cooperative diversity network decode-and-forward protocol maximum-likelihood (ML) performance maximum logarithm (max-log) approximation

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ML Performance Analysis of the decode-and-forward protocol in Cooperative Diversity Networks

ML Performance Analysis of the Decode-and-Forward Protocol i...

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3rd International Workshop on Wireless Mesh and Ad Hoc Networks (WiMAN 2009)

作者： Ju, MinChul Kim, Il-Min Queens Univ Dept Elect & Comp Engn Kingston ON Canada

关键词： Bit-error rate (BER) cooperative diversity network decode-and-forward protocol maximum-likelihood (ML) performance maximum logarithm (max-log) approximation

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ML Performance Analysis of the decode-and-forward protocol in Multi-Hop Networks

ML Performance Analysis of the Decode-and-Forward Protocol i...

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29th IEEE International Conference on Distributed Computing Systems

作者： Ju, MinChul Kim, Il-Min Queens Univ ECE Kingston ON Canada

ISBN: (纸本)9781424444465

We analyze the maximum-likelihood (ML) performance of the decode-and-forward protocol in a cooperative diversity network which consists of a source, a relay, and a destination with a direct path signal. We first present an approximated ML detection rule by adopting max-log approximation. Then we obtain decision regions in a form without union and intersection. Finally, based on the decision regions, we derive a very accurate closed-form BER approximation for M-pulse amplitude modulation (PAM) and M-quadrature amplitude modulation (QAM).

关键词： Cooperative diversity network decode-and-forward protocol maximum-likelihood (ML) performance

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Joint Relay Selection and Network Coding Using decode-and-forward protocol in Two-Way Relay Channels

Joint Relay Selection and Network Coding Using Decode-and-Fo...

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IEEE Global Telecommunications Conference (GLOBECOM 2010)

作者： You, Qimin Li, Yonghui Chen, Zhuo Univ Sydney Sydney NSW 2006 Australia

ISBN: (纸本)9781424456383

In this paper, we analyze the bit error rate (BER) performance of a single relay selection with network coding (S-RS-NC) scheme in two-way relay channels. In this scheme, two source nodes first broadcast their information to the relays sequentially. A single relay which optimizes the system performance is selected. The selected relay decodes the received signals from two sources, performs network coding on two symbol estimates and then forwards them to two source nodes. Equivalent signal-to-noise-ratio (SNR) of the whole source-relay-destination link is analyzed and its high SNR approximation is derived. Closed-form BER expressions are then derived and the results are verified through Monte-Carlo simulations which show that the derived analytical expressions offer a tight bound for the average BER. It is shown that this S-RS-NC scheme can achieve a full diversity order as if all relays were used. Simulation results show that the S-RS-NC scheme can bring considerable gains over the all-participation relaying scheme when the source transmission power is larger than or equal to the relay transmission power. However, when the relay transmission power is greater than the source power, the single relay selection scheme could be inferior to the all-participation relaying scheme. This is quite different from the conventional relay selection scheme in one way relay network, where the relay selection always outperforms the all participation relaying scheme.

关键词： Monte Carlo methods Monte Carlo simulation S-RS-NC scheme SNR approximation approximation theory bit error rate closed-form BER expression decode and forward communication decode-and-forward protocol error statistics network coding network coding protocol

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Constructions of DMT Optimal Vector Codes for Asynchronous Cooperative Networks Using decode-and-forward protocols

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2010年第7期9卷 2392-2400页

作者： Lu, Hsiao-feng Francis Natl Chiao Tung Univ Dept Elect Engn Hsinchu Taiwan

An asynchronous cooperative network where different time delays exist among nodes is considered in this paper. Assuming the signals are OFDM modulated, it is first shown that the diversity-multiplexing tradeoff (DMT) achieved by the non-orthogonal selection decode-and-forward (NSDF) protocol for this network is the same as that for the synchronous one. In contrast to the complicated approximately universal "matrix" codes, where each relay uses a different codebook, a systematic construction of an extremely simple "vector" code is proposed. Given the transmitted codeword vector, this vector will be used by all nodes in the network for signal transmission;hence, the proposed coding scheme greatly reduces the complexity of relay deployment and decoding. Furthermore, it is proven that the proposed scheme is optimal in terms of the DMT of the NSDF protocol for this asynchronous network, provided all time delays are distinct. Finally, it is shown that the proposed code design can be extended to the orthogonal selection decode-and-forward protocol and remains to be DMT optimal.

关键词： Asynchronous cooperative network cyclic division algebra decode-and-forward protocol diversity-multiplexing gain tradeoff multi-block space-time code

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Adaptive Relaying in Noncoherent Cooperative Networks

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IEEE TRANSACTIONS ON SIGNAL PROCESSING 2010年第7期58卷 3938-3945页

作者： Nguyen, Ha X. Nguyen, Ha H. Univ Saskatchewan Dept Elect & Comp Engn Saskatoon SK S7N 5A9 Canada

This correspondence considers a cooperative network in which binary frequency-shift-keying (BFSK) modulation is employed to facilitate noncoherent communications between a source and a destination with the help of relays. Proposed is an adaptive cooperative scheme that employs two thresholds as follows. One threshold is used to select retransmitting relays: a relay retransmits to the destination if its decision variable is larger than the threshold, otherwise it remains silent. The other threshold is used at the destination for detection: the destination marks a relay as a retransmitting relay if the decision variable corresponding to the relay is larger than the threshold, otherwise, the destination marks it as a silent relay. Then the destination combines the signals from the retransmitting relays and from the source to make the final decision. The average end-to-end (e2e) bit-error rate (BER) is derived in a closed-form expression for a two-relay network. The problems of selecting optimal thresholds or jointly optimal thresholds and power allocation to minimize the average BER are investigated. Simulation results are provided to validate our analysis. Compared to the previously proposed piecewise-linear (PL) detection scheme, our proposed scheme yields a superior performance under a wide range of channel conditions when optimal thresholds or jointly optimal thresholds and power allocation are employed.

关键词： Cooperative diversity decode-and-forward protocol fading channel frequency-shift-keying relay communications

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Practical relay code design based on protograph codes

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IET COMMUNICATIONS 2018年第3期12卷 334-339页

作者： Noor-A-Rahim, Md. Ali, G. G. Md. Nawaz Guan, Yong Liang Nanyang Technol Univ Ctr Infocomm Technol INFINITUS Singapore Singapore

The low-density parity-check (LDPC) code design for three-terminal (namely, source, relay, and destination) relay network while considering decode-and-forward protocol is studied. Numerous works have been done on LDPC relay code design with parity bits forwarding approach, where additional parity bits are generated at the relay and forwarded to the destination. Most of the previous works assume that the forwarded parity bits are received perfectly at the destination and hence ignore the impact of relay-destination channel. This assumption is unrealistic in practical/finite-length codeword scenario. In this study, a protograph based LDPC code design is proposed while lifting the above unrealistic assumption. A Gaussian approximated density evolution is presented for the proposed scheme, which considers that the overall codeword experiences source-destination and relay-destination channels. For various designed codes with different rates, the authors show that the asymptotic thresholds of the designed codes are very close to the corresponding capacity bounds. Asymptotically, our designed code gives similar decoding threshold compared to the existing optimised irregular LDPC codes, while protograph codes are simpler to optimise and encode than the irregular LDPC codes. More importantly, proposed code performs better than the existing LDPC-based relay codes for finite-length scenarios.

关键词： relay networks (telecommunication) decode and forward communication protocols parity check codes channel coding Gaussian processes approximation theory practical relay code design protograph codes low-density parity-check code design three-terminal relay network destination relay network source relay network decode-and-forward protocol LDPC relay code design parity bits forwarding approach relay-destination channel finite-length codeword Gaussian approximated density evolution source-destination channels asymptotic thresholds decoding threshold capacity bounds

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Cooperative communication protocols in wireless networks: Performance analysis and optimum power allocation

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WIRELESS PERSONAL COMMUNICATIONS 2008年第2期44卷 181-217页

作者： Su, Weifeng Sadek, Ahmed K. Liu, K. J. Ray SUNY Buffalo Dept Elect Engn Buffalo NY 14260 USA Univ Maryland Dept Elect & Comp Engn College Pk MD 20742 USA

In this paper, symbol-error-rate (SER) performance analysis and optimum power allocation are provided for uncoded cooperative communications in wireless networks with either decode-and-forward (DF) or amplify-and-forward (AF) cooperation protocol, in which source and relay send information to destination through orthogonal channels. In case of the DF cooperation systems, closed-form SER formulation is provided for uncoded cooperation systems with PSK and QAM signals. Moreover, an SER upper bound as well as an approximation are established to show the asymptotic performance of the DF cooperation systems, where the SER approximation is asymptotically tight at high signal-to-noise ratio (SNR). Based on the asymptotically tight SER approximation, an optimum power allocation is determined for the DF cooperation systems. In case of the AF cooperation systems, we obtain at first a simple closed-form moment generating function (MGF) expression for the harmonic mean to avoid the hypergeometric functions as commonly used in the literature. By taking advantage of the simple MGF expression, we obtain a closed-form SER performance analysis for the AF cooperation systems with PSK and QAM signals. Moreover, an SER approximation is also established which is asymptotically tight at high SNR. Based on the asymptotically tight SER approximation, an optimum power allocation is determined for the AF cooperation systems. In both the DF and AF cooperation systems, it turns out that an equal power strategy is good, but in general not optimum in cooperative communications. The optimum power allocation depends on the channel link quality. An interesting result is that in case that all channel links are available, the optimum power allocation does not depend on the direct link between source and destination, it depends only on the channel links related to the relay. Finally, we compare the performance of the cooperation systems with either DF or AF protocol. It is shown that the performance o

关键词： cooperative communications amplify-and-forward protocol decode-and-forward protocol symbol error rate performance analysis optimum power allocation wireless networks

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