On the Achievable Throughput of a Multiantenna
On the Achievable Throughput of a Multiantenna
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DOI：
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发表时间：
2003
影响因子：
2.8
通讯作者：
G. Caire;S. Shamai
中科院分区：
文献类型：
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作者：
G. Caire;S. Shamai
考虑了在发射机具有单天线接收器和天线的高斯广播信道(GBC)。发射机和接收机都对信道有很好的了解。尽管其表面上很简单，但该模型通常是非降级广播信道(BC)，其容量区域并不完全已知。对于两个用户的情况，我们找到了马顿域的一个特例，它实现了最优和速率(吞吐量)。简而言之，发射机将信道分解为两个干扰信道，其中干扰由另一个用户信号引起。用户被连续编码，使得第二用户的编码基于第一用户引起的干扰的非因果知识。串扰参数经过优化，从而使总吞吐量达到最大，令人惊讶的是，这在所有可能的策略中都是最优的(不仅是相对于马顿的可实现区域)。对于用户的情况，我们发现基于对用户的排序和连续编码的马顿区域的选择稍微简单一些。对于给定顺序中的每个用户，通过在发射机上强制零来消除用户造成的干扰，而通过对非因果已知干扰进行编码来计入用户造成的干扰。在一定的温和条件下，对于高信噪比和低信噪比，该方案都是吞吐量渐近最优的。最后，我们给出了独立瑞利衰落下简化的逼零方案的遍历吞吐量的一些数值结果。
A Gaussian broadcast channel (GBC) with single-antenna receivers and antennas at the transmitter is con- sidered. Both transmitter and receivers have perfect knowledge of the channel. Despite its apparent simplicity, this model is, in general, a nondegraded broadcast channel (BC), for which the capacity region is not fully known. For the two-user case, we find a special case of Marton's region that achieves optimal sum-rate (throughput). In brief, the transmitter decomposes the channel into two interference channels, where interference is caused by the other user signal. Users are successively encoded, such that encoding of the second user is based on the noncausal knowledge of the interference caused by the first user. The crosstalk parameters are optimized such that the overall throughput is maximum and, surprisingly, this is shown to be optimal over all possible strategies (not only with respect to Marton's achievable region). For the case of users, we find a somewhat simpler choice of Marton's region based on ordering and successively encoding the users. For each user in the given ordering, the interference caused by users is eliminated by zero forcing at the trans- mitter, while interference caused by users is taken into ac- count by coding for noncausally known interference. Under certain mild conditions, this scheme is found to be throughput-wise asymp- totically optimal for both high and low signal-to-noise ratio (SNR). We conclude by providing some numerical results for the ergodic throughput of the simplified zero-forcing scheme in independent Rayleigh fading.