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arXiv 0911.0905cs.ITmath.IT
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多天线互易信道中训练与量化反馈的结合

Combining Training and Quantized Feedback in Multi-Antenna Reciprocal Channels

Umer Salim, David Gesbert, Dirk Slock

摘要:

通过在用户的发射机(CSIT)处提供信道状态信息,可以显著增强多天线发射机与各自具有单天线或多天线的多个接收机(用户)之间的通信,因为这允许调度、波束成形和多用户复用增益。到目前为止,关于如何启用CSIT的传统观点如下:在时分双工(TDD)系统中,上行链路(UL)和下行链路(DL)信道互易性允许在UL方向上使用训练序列,该训练序列被用来获得UL信道估计。该估计又在下一个下行链路时隙中被再循环。在缺乏UL和DL互易性的频分双工(FDD)系统中,通过使用接收机和发射机之间的有限容量的专用反馈链路来提供CSIT。在本文中,我们专注于TDD系统,并把这个经典的方法的问题。特别是,我们表明,传统的TDD设置上述未能充分利用其真正意义上的信道互易性。事实上,我们表明,该系统可以受益于结合CSIT收购策略混合使用有限的反馈和训练序列。这种结合产生了一个非常有趣的联合估计和检测问题,我们提出了两个迭代算法。一个中断率为基础的框架,它给出了最佳的资源分配之间的培训和反馈。我们证明了这种混合组合的潜力,在全球培训和反馈资源的约束下,提高CSIT质量。

英文摘要:

The communication between a multiple-antenna transmitter and multiple receivers (users) with either a single or multiple-antenna each can be significantly enhanced by providing the channel state information at the transmitter (CSIT) of the users, as this allows for scheduling, beamforming and multiuser multiplexing gains. The traditional view on how to enable CSIT has been as follows so far: In time-division duplexed (TDD) systems, uplink (UL) and downlink (DL) channel reciprocity allows the use of a training sequence in the UL direction, which is exploited to obtain an UL channel estimate. This estimate is in turn recycled in the next downlink slot. In frequency-division duplexed (FDD) systems, which lack the UL and DL reciprocity, the CSIT is provided via the use of a dedicated feedback link of limited capacity between the receivers and the transmitter. In this paper, we focus on TDD systems and put this classical approach in question. In particular, we show that the traditional TDD setup above fails to fully exploit the channel reciprocity in its true sense. In fact, we show that the system can benefit from a combined CSIT acquisition strategy mixing the use of limited feedback and that of a training sequence. This combining gives rise to a very interesting joint estimation and detection problem for which we propose two iterative algorithms. An outage rate based framework is also developed which gives the optimal resource split between training and feedback. We demonstrate the potential of this hybrid combining in terms of the improved CSIT quality under a global training and feedback resource constraint.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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