On the optimality of multiantenna broadcast scheduling using zero-forcing beamforming
On the optimality of multiantenna broadcast scheduling using zero-forcing beamforming
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DOI：
10.1109/jsac.2005.862421
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发表时间：
2006-03-01
影响因子：
16.4
通讯作者：
Goldsmith, A
中科院分区：
文献类型：
--
作者：
Yoo, T;Goldsmith, A
虽然多输入多输出（MIMO）广播信道（BC）的容量可以通过脏纸编码（DPC）来实现，但它在实际系统中很难实现。本文探讨了如果，对于大量用户，较简单的方案可以实现相同的性能。具体来说，我们表明，迫零波束形成（ZFBF）的策略，而一般次优，可以实现相同的渐近和容量的DPC，用户的数量趋于无穷大。在证明这一渐近结果，我们提供了一个算法来确定哪些用户应该是活跃的ZFBF。这些用户彼此半正交，并且可以被分组用于同时传输以提高调度算法的吞吐量。在用户分组的基础上，提出并比较了循环ZFBF和比例公平ZFBF两种公平调度方案。我们提供了数值结果，以确认ZFBF的最优性，并比较ZFBF的性能，提出公平的调度方案与各种MIMO BC策略。
Although the capacity of multiple-input/multiple-output (MIMO) broadcast channels (BCs) can be achieved by dirty paper coding (DPC), it is difficult to implement in practical systems. This paper investigates if., for a large number of users, simpler schemes can achieve the same performance. Specifically, we show that a zero-forcing beamforming (ZFBF) strategy, while generally suboptimal, can achieve the same asymptotic sum capacity as that of DPC, as the number of users goes to infinity. In proving this asymptotic result, we provide an algorithm for determining which users should be active under ZFBF. These users are semiorthogonal to one another and can be grouped for simultaneous transmission to enhance the throughput of scheduling algorithms. Based on the user grouping, we propose and compare two fair scheduling schemes in round-robin ZFBF and proportional-fair ZFBF. We provide numerical results to confirm the optimality of ZFBF and to compare the performance of ZFBF and proposed fair scheduling schemes with that of various MIMO BC strategies.