Network Coding (NC) brings correlation between the coded signals from different sources, which makes the system more vulnerable to the decode error at relay. Conventional Cyclic Redundancy Code (CRC) has been implemen...Network Coding (NC) brings correlation between the coded signals from different sources, which makes the system more vulnerable to the decode error at relay. Conventional Cyclic Redundancy Code (CRC) has been implemented for error bit detection. However, its error correction is simply ignored. To fully exploit this feature, this paper proposes a novel joint Log-Likelihood Ratio (LLR) CRC error mitigation for NC two way relay channel. Specific thresholds are designed to estimate the error number of data block and identify those which can be recovered if the number is within the error correction scope of CRC. We examine two modes of the thresholds, one based on the average Bit Error Rate (BER) of source-relay link, while the other based on that of instantaneous one. We provide the full analysis for the Pair-wise Error Probability (PEP) performance of the scheme. A variety of numerical results are presented to reveal the superiority of the proposed scheme to conventional CRC NC under independent Rayleigh fading channels. Moreover, the efficiencies of the proposed thresholds are also validated.展开更多
Error propagation seriously degenerate the diversity order of Decode-and-Forward (DF) cooperative communication. To address this problem, a novel Log Likelihood Ratio (LLR)-based Link Adaptive Relaying (LAR) is propos...Error propagation seriously degenerate the diversity order of Decode-and-Forward (DF) cooperative communication. To address this problem, a novel Log Likelihood Ratio (LLR)-based Link Adaptive Relaying (LAR) is proposed to promote adaption accuracy at relay. The instantaneous Bit Error Probability (BEP) is calculated according to the LLR of the received signals firstly, then based on it, the equivalent Signal-to-Noise Ratio (SNR) is employed to operate dynamic power scaling by relay. It is theoretically proved that the full diversity order can be attained by the scheme. Besides, the power sensitivity is also analyzed. Simulation results show that the proposed scheme outperform the conventional LAR and can achieve full diversity order. Moreover, its strong adaptation to SNR fluctuation is validated.展开更多
Network Coding (NC) is an effective technology to enhance the cooperative system spectral efficiency. However, since it is network-oriented, the existing performance metric of single-user outage can not comprehensivel...Network Coding (NC) is an effective technology to enhance the cooperative system spectral efficiency. However, since it is network-oriented, the existing performance metric of single-user outage can not comprehensively evaluate its gain and the impact to the entire network, which affect the user fairness. This paper proposes two novel user fair-based adaptive relay power allocation algorithms in single-relay NC cooperative multiple access channels. Firstly, common outage probability is employed as the performance metric, and to minimize it, a specific condition is deduced. On this basis, the instantaneous channel information-based adaptive relay power allocation scheme and the channel statistic information-based one with lower complexity are designed respectively, which make users' signals superimposed at accurately calculated proportion to maintain fairness. Simulation results show that compared with other existing schemes, the proposed schemes can best maintain user fairness, and effectively improve the common outage performance of the whole system, at the expense of small spectral efficiency.展开更多
基金Supported by the National 973 Programs (2013CB329104)the National Natural Science Foundations of China (No. 61071090, No. 61171093)+3 种基金the Postgraduate Innovation Programs of Scientific Research of Jiangsu Province (CXZZ11_0388)Jiangsu Province Natural Science Foundation Key Projects (11KJA510001)National Science and Technology Key Projects (2011ZX03005-004-003)Jiangsu 973 Projects (BK2011027)
文摘Network Coding (NC) brings correlation between the coded signals from different sources, which makes the system more vulnerable to the decode error at relay. Conventional Cyclic Redundancy Code (CRC) has been implemented for error bit detection. However, its error correction is simply ignored. To fully exploit this feature, this paper proposes a novel joint Log-Likelihood Ratio (LLR) CRC error mitigation for NC two way relay channel. Specific thresholds are designed to estimate the error number of data block and identify those which can be recovered if the number is within the error correction scope of CRC. We examine two modes of the thresholds, one based on the average Bit Error Rate (BER) of source-relay link, while the other based on that of instantaneous one. We provide the full analysis for the Pair-wise Error Probability (PEP) performance of the scheme. A variety of numerical results are presented to reveal the superiority of the proposed scheme to conventional CRC NC under independent Rayleigh fading channels. Moreover, the efficiencies of the proposed thresholds are also validated.
基金Supported by the National Natural Science Foundationsof China(No.61071090,No.61171093)the Postgraduate Innovation Programs of Scientific Research of Jiangsu Province(CXZZ11_0388,CXLX11_0404)+2 种基金Jiangsu Province Natural Science Foundation Key Projects(11-KJA510001)National Science and Technology KeyProjects(2011ZX03005-004-003)Jiangsu 973 Projects(BK2011027)
文摘Error propagation seriously degenerate the diversity order of Decode-and-Forward (DF) cooperative communication. To address this problem, a novel Log Likelihood Ratio (LLR)-based Link Adaptive Relaying (LAR) is proposed to promote adaption accuracy at relay. The instantaneous Bit Error Probability (BEP) is calculated according to the LLR of the received signals firstly, then based on it, the equivalent Signal-to-Noise Ratio (SNR) is employed to operate dynamic power scaling by relay. It is theoretically proved that the full diversity order can be attained by the scheme. Besides, the power sensitivity is also analyzed. Simulation results show that the proposed scheme outperform the conventional LAR and can achieve full diversity order. Moreover, its strong adaptation to SNR fluctuation is validated.
基金Supported by the National Natural Science Foundations of China (No. 61071090, No. 61171093)the Postgraduate Innovation Programs of Scientific Research of Jiangsu Province (CXZZ11_0388, CXLX11_0404)+2 种基金Jiangsu Province Natural Science Foundation Key Projects (11K-JA510001)National Science and Technology Key Projects (2011ZX03005-004-003)Jiangsu 973 (BK20-11027)
文摘Network Coding (NC) is an effective technology to enhance the cooperative system spectral efficiency. However, since it is network-oriented, the existing performance metric of single-user outage can not comprehensively evaluate its gain and the impact to the entire network, which affect the user fairness. This paper proposes two novel user fair-based adaptive relay power allocation algorithms in single-relay NC cooperative multiple access channels. Firstly, common outage probability is employed as the performance metric, and to minimize it, a specific condition is deduced. On this basis, the instantaneous channel information-based adaptive relay power allocation scheme and the channel statistic information-based one with lower complexity are designed respectively, which make users' signals superimposed at accurately calculated proportion to maintain fairness. Simulation results show that compared with other existing schemes, the proposed schemes can best maintain user fairness, and effectively improve the common outage performance of the whole system, at the expense of small spectral efficiency.
