For decreasing the multiple access interference of weaker signal acquisition in direct sequence spread spectrum（DSSS） systems,a new single decision algorithm is presented.The maximum value of correlation results is ...For decreasing the multiple access interference of weaker signal acquisition in direct sequence spread spectrum（DSSS） systems,a new single decision algorithm is presented.The maximum value of correlation results is conventionally detected.However,there may be not only one strong peak among correlation results when the cross-correlation noise is strong enough to affect the correlation results.The proposed algorithm decreases the false alarm probability through the decision of the ratio of the maximum value and the second maximum value of the correlation results.Theoretical analysis and simulation results indicate that the proposed algorithm effectively suppresses the acquisition problem of multiple access interference in DSSS system.展开更多
High complexity and high latency are key problems for multiuser detection （MUD） to be applied to a mobile station in cellular networks. To tackle these problems, an interleave division multiple access （IDMA） based...High complexity and high latency are key problems for multiuser detection （MUD） to be applied to a mobile station in cellular networks. To tackle these problems, an interleave division multiple access （IDMA） based multiple access scheme, grouped spread IDMA （GSIDMA）, is proposed. In a GSIDMA system, lower complexity and latency for mobile stations can be achieved by appropriately dividing active users into different groups. The system model of GSIDMA is constructed and followed by analysing on its system capacity, complexity and latency, and bit error rate （BER） performance. The extrinsic information transfer （EXIT） chart is used to analyze the convergence behavior of the iteration process. The grouping method and interleavers-reuse issue for GSIDMA are also discussed preliminarily. The analyses and simulation results indicate that the complexity and latency of the proposed scheme are much lower than those of IDMA, whereas its BER performance is close to the latter. The properties of low complexity and low latency make it more feasible for the practical implementation.展开更多
Many blind channel estimation methods have been proposed for direct sequence (DS) code-division multiple access (CDMA) systems, so we can certainly use them to estimate the finite impulse response (FIR) channel for th...Many blind channel estimation methods have been proposed for direct sequence (DS) code-division multiple access (CDMA) systems, so we can certainly use them to estimate the finite impulse response (FIR) channel for the multi-carrier (MC-) CDMA system. In this paper, the MC-CDMA system is interpreted as an equivalent time-domain DS-CD-MA system with specific spreading codes. Then, an equivalently time-domain blind channel estimator is derived for the uplink MC-CDMA, which is based on second-order statistics of the received data. By exploiting singular value decomposition (SVD) and the finite alphabet property of transmitted symbols, the time-domain channel impulse response (CIR) for the uplink MC-CDMA can be accurately identified. Computer simulations illustrate both the validity and the overall performance of the proposed estimator.展开更多
为了解决移动通信系统中的高延迟和覆盖盲点问题,提出了一种基于认知无线电-非正交多址接入(Cognitive Radio Non-orthogonal Multiple Access,CR-NOMA)的工业物联网网络。在认知网络中次用户采用解码转发(Decode and Forward,DF)和放...为了解决移动通信系统中的高延迟和覆盖盲点问题,提出了一种基于认知无线电-非正交多址接入(Cognitive Radio Non-orthogonal Multiple Access,CR-NOMA)的工业物联网网络。在认知网络中次用户采用解码转发(Decode and Forward,DF)和放大转发(Amplify and Forward,AF)两种辅助解码方式下,推导了主用户和次用户在完全串行干扰或不完全串行干扰两种终端状态下的中断性能。当用户间链路条件相同时,认知中继采用AF方式优于DF方式,且不完全串行干扰技术后系统残留干扰噪声的增大也会导致主用户和次用户的中断概率增大。研究还发现,各用户移动导致用户之间距离增大时,主用户和次用户的中断概率也会增大。展开更多
基金supported by the National High Technology ResearchDevelopment Program of China (863 Program) (2008AA0248)
文摘For decreasing the multiple access interference of weaker signal acquisition in direct sequence spread spectrum（DSSS） systems,a new single decision algorithm is presented.The maximum value of correlation results is conventionally detected.However,there may be not only one strong peak among correlation results when the cross-correlation noise is strong enough to affect the correlation results.The proposed algorithm decreases the false alarm probability through the decision of the ratio of the maximum value and the second maximum value of the correlation results.Theoretical analysis and simulation results indicate that the proposed algorithm effectively suppresses the acquisition problem of multiple access interference in DSSS system.
基金supported by the National Natural Science Foundation of China (61171180)the National Basic Resaearch Program (923 Program) (2007CB31(0606))the Natural Sientific Research Innovation Foundation in Harbin Institute of Technology (HIT. NSRIF20011117)
文摘High complexity and high latency are key problems for multiuser detection （MUD） to be applied to a mobile station in cellular networks. To tackle these problems, an interleave division multiple access （IDMA） based multiple access scheme, grouped spread IDMA （GSIDMA）, is proposed. In a GSIDMA system, lower complexity and latency for mobile stations can be achieved by appropriately dividing active users into different groups. The system model of GSIDMA is constructed and followed by analysing on its system capacity, complexity and latency, and bit error rate （BER） performance. The extrinsic information transfer （EXIT） chart is used to analyze the convergence behavior of the iteration process. The grouping method and interleavers-reuse issue for GSIDMA are also discussed preliminarily. The analyses and simulation results indicate that the complexity and latency of the proposed scheme are much lower than those of IDMA, whereas its BER performance is close to the latter. The properties of low complexity and low latency make it more feasible for the practical implementation.
基金This project was supported by the National Natural Science Foundation of China (No. 69872029) the Research Fund for Doctoral Program of Higher Education of China (No. 1999069808).
文摘Many blind channel estimation methods have been proposed for direct sequence (DS) code-division multiple access (CDMA) systems, so we can certainly use them to estimate the finite impulse response (FIR) channel for the multi-carrier (MC-) CDMA system. In this paper, the MC-CDMA system is interpreted as an equivalent time-domain DS-CD-MA system with specific spreading codes. Then, an equivalently time-domain blind channel estimator is derived for the uplink MC-CDMA, which is based on second-order statistics of the received data. By exploiting singular value decomposition (SVD) and the finite alphabet property of transmitted symbols, the time-domain channel impulse response (CIR) for the uplink MC-CDMA can be accurately identified. Computer simulations illustrate both the validity and the overall performance of the proposed estimator.
文摘为了解决移动通信系统中的高延迟和覆盖盲点问题,提出了一种基于认知无线电-非正交多址接入(Cognitive Radio Non-orthogonal Multiple Access,CR-NOMA)的工业物联网网络。在认知网络中次用户采用解码转发(Decode and Forward,DF)和放大转发(Amplify and Forward,AF)两种辅助解码方式下,推导了主用户和次用户在完全串行干扰或不完全串行干扰两种终端状态下的中断性能。当用户间链路条件相同时,认知中继采用AF方式优于DF方式,且不完全串行干扰技术后系统残留干扰噪声的增大也会导致主用户和次用户的中断概率增大。研究还发现,各用户移动导致用户之间距离增大时,主用户和次用户的中断概率也会增大。
