协同分集(cooperative diversity)技术通过使网络中各单天线用户共享彼此天线,形成虚拟的多天线阵列来实现发射或接收分集,可以有效地提高系统性能。该文提出无线网络中频率选择性衰落信道环境下的一种基于分布式空时分组码(Distributed...协同分集(cooperative diversity)技术通过使网络中各单天线用户共享彼此天线,形成虚拟的多天线阵列来实现发射或接收分集,可以有效地提高系统性能。该文提出无线网络中频率选择性衰落信道环境下的一种基于分布式空时分组码(Distributed Space Time Block Code,DSTBC)和MC-CDMA的协同发射分集方案,并给出了系统实现。建立了误码模型,探讨了协同用户间的信道状态信息(CSI)对系统误码性能的影响,分析了误码性能的上限,并给出了仿真结果。结果表明,DSTBC-MC-CDMA系统相对于未协同的MC-CDMA系统,获得了明显的性能增益。展开更多
本文首先建立了采用TR-STBC发送分集的MIMO MC DS-CDMA系统模型,然后在此基础上,研究了SDCMA盲均衡在该系统中的应用,最后进行了仿真和分析。结论是对采用TR-STBC方案的MIMO MC DS-CDMA系统进行常模盲均衡,算法简单,较易实现,但当多址...本文首先建立了采用TR-STBC发送分集的MIMO MC DS-CDMA系统模型,然后在此基础上,研究了SDCMA盲均衡在该系统中的应用,最后进行了仿真和分析。结论是对采用TR-STBC方案的MIMO MC DS-CDMA系统进行常模盲均衡,算法简单,较易实现,但当多址干扰较大时,仅采用此均衡方法不能较好地改善系统性能,还需要进一步采用其他方法来减小或消除多址干扰。展开更多
In this paper, an adaptive co-channel interference suppression technique for multi-user MIMO MC DS/CDMA system is envisaged. MC DS/CDMA offers many advantages like flexibility, robustness, low PAPR and spectral effici...In this paper, an adaptive co-channel interference suppression technique for multi-user MIMO MC DS/CDMA system is envisaged. MC DS/CDMA offers many advantages like flexibility, robustness, low PAPR and spectral efficiency. In spite of these advantages, performance of MC DS/CDMA system is greatly impaired by interference. Common interferences, which degrade the performance of the system, are MAI and CCI. Mitigating these interferences can directly increase the capacity of the system. In this work, an adaptive co-channel interference suppression technique based on single-stage and two-stage MMSE IC is considered for multi-user MIMO MC DS/CDMA system. Simulation results show that, at low SNR two-stage MMSE IC outperforms single-stage, while at high SNR, single-stage provides better BER performance. Based on this, a selection criterion has been propounded for improved system performance as a whole in interference limited environment. Also, adaptive selection criterion resulted in better error performance.展开更多
We consider the uplink of a multiuser, multiple-input multiple-output (MIMO), frequency-time-domain spread, multi- carrier (MC), direct sequence code division multiple access (DS-CDMA) system. As other CDMA-like syste...We consider the uplink of a multiuser, multiple-input multiple-output (MIMO), frequency-time-domain spread, multi- carrier (MC), direct sequence code division multiple access (DS-CDMA) system. As other CDMA-like systems, the multiple access interference (MAI) effect still exists in such an MC DS-CDMA system. To mitigate the MAI effect, we propose user-based and group-based layered detection schemes. Specifically, to enable a trade-off between the performance and the computational complexity, the schemes only use one user's/group's soft decisions for user-based/ group-based layered detection. The results of simulations demonstrate that the proposed schemes outperform existing approaches, and their computational complexity is modest.展开更多
文摘协同分集(cooperative diversity)技术通过使网络中各单天线用户共享彼此天线,形成虚拟的多天线阵列来实现发射或接收分集,可以有效地提高系统性能。该文提出无线网络中频率选择性衰落信道环境下的一种基于分布式空时分组码(Distributed Space Time Block Code,DSTBC)和MC-CDMA的协同发射分集方案,并给出了系统实现。建立了误码模型,探讨了协同用户间的信道状态信息(CSI)对系统误码性能的影响,分析了误码性能的上限,并给出了仿真结果。结果表明,DSTBC-MC-CDMA系统相对于未协同的MC-CDMA系统,获得了明显的性能增益。
文摘本文首先建立了采用TR-STBC发送分集的MIMO MC DS-CDMA系统模型,然后在此基础上,研究了SDCMA盲均衡在该系统中的应用,最后进行了仿真和分析。结论是对采用TR-STBC方案的MIMO MC DS-CDMA系统进行常模盲均衡,算法简单,较易实现,但当多址干扰较大时,仅采用此均衡方法不能较好地改善系统性能,还需要进一步采用其他方法来减小或消除多址干扰。
文摘In this paper, an adaptive co-channel interference suppression technique for multi-user MIMO MC DS/CDMA system is envisaged. MC DS/CDMA offers many advantages like flexibility, robustness, low PAPR and spectral efficiency. In spite of these advantages, performance of MC DS/CDMA system is greatly impaired by interference. Common interferences, which degrade the performance of the system, are MAI and CCI. Mitigating these interferences can directly increase the capacity of the system. In this work, an adaptive co-channel interference suppression technique based on single-stage and two-stage MMSE IC is considered for multi-user MIMO MC DS/CDMA system. Simulation results show that, at low SNR two-stage MMSE IC outperforms single-stage, while at high SNR, single-stage provides better BER performance. Based on this, a selection criterion has been propounded for improved system performance as a whole in interference limited environment. Also, adaptive selection criterion resulted in better error performance.
文摘We consider the uplink of a multiuser, multiple-input multiple-output (MIMO), frequency-time-domain spread, multi- carrier (MC), direct sequence code division multiple access (DS-CDMA) system. As other CDMA-like systems, the multiple access interference (MAI) effect still exists in such an MC DS-CDMA system. To mitigate the MAI effect, we propose user-based and group-based layered detection schemes. Specifically, to enable a trade-off between the performance and the computational complexity, the schemes only use one user's/group's soft decisions for user-based/ group-based layered detection. The results of simulations demonstrate that the proposed schemes outperform existing approaches, and their computational complexity is modest.
