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arXiv 0807.4881cs.ITmath.IT
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基于波束置零的自适应MIMO系统容量与性能

Capacity and Performance of Adaptive MIMO System Based on Beam-Nulling

Mabruk Gheryani, Zhiyuan Wu, Yousef R. Shayan

摘要:

在本文中,我们提出了一种称为“波束调零”的MIMO自适应方案。在波束调零方案中,反馈最弱子信道的特征向量,然后在与最弱子信道正交的生成子空间上发送信号。理论分析和数值结果表明,在中等信噪比下,该方法的波束零陷能力接近于最优注水。此外,推导了波束置零时MMSE接收机的信干噪比。在此基础上,给出了波束置零的平均出错率,并通过仿真进行了验证。仿真结果还提供了比较波束置零与波束形成。为了进一步提高性能,波束置零与线性色散码级联。仿真结果还提供了在相同的数据率的级联波束置零方案与波束成形方案进行比较。此外,如果在发射机处有多于一个特征向量可用,则可以扩展现有的波束成形和新提出的波束置零。新的扩展方案被称为多维(MD)波束形成和MD波束置零。理论分析和数值结果的能力方面也提供了新的扩展计划进行评估。仿真结果表明,在数据率较高的情况下,采用LDC的MD方案的性能明显优于采用STBC的MD方案。

英文摘要:

In this paper, we propose a scheme called "beam-nulling" for MIMO adaptation. In the beam-nulling scheme, the eigenvector of the weakest subchannel is fed back and then signals are sent over a generated subspace orthogonal to the weakest subchannel. Theoretical analysis and numerical results show that the capacity of beam-nulling is closed to the optimal water-filling at medium SNR. Additionally, signal-to-interference-plus-noise ratio (SINR) of MMSE receiver is derived for beam-nulling. Then the paper presents the associated average bit-error rate (BER) of beam-nulling numerically which is verified by simulation. Simulation results are also provided to compare beam-nulling with beamforming. To improve performance further, beam-nulling is concatenated with linear dispersion code. Simulation results are also provided to compare the concatenated beam-nulling scheme with the beamforming scheme at the same data rate. Additionally, the existing beamforming and new proposed beam-nulling can be extended if more than one eigenvector is available at the transmitter. The new extended schemes are called multi-dimensional (MD) beamforming and MD beam-nulling. Theoretical analysis and numerical results in terms of capacity are also provided to evaluate the new extended schemes. Simulation results show that the MD scheme with LDC can outperform the MD scheme with STBC significantly when the data rate is high.

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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