Quality of service and max-min fair transmit beamforming to multiple cochannel multicast groups
Quality of service and max-min fair transmit beamforming to multiple cochannel multicast groups
复制标题
DOI：
10.1109/tsp.2007.909010
复制
发表时间：
2008-03-01
影响因子：
5.4
通讯作者：
Luo, Zhi-Quan
中科院分区：
文献类型：
--
作者：
Karipidis, Eleftherios;Sidiropoulos, Nicholas D.;Luo, Zhi-Quan
多个同信道多播组的发射波束成形的问题被认为是，当信道状态是已知的发射机和从两个角度：最小化总发射功率，同时保证规定的最小信号干扰噪声比（SINR）在每个接收机;和“公平”的方法，最大限度地提高整体最小SINR下的总功率预算。核心问题是多用户下行链路波束成形问题的多播推广;不同之处在于，每个发送的流被定向到多个接收器，每个接收器都有自己的信道。这种概括是相关的和及时的，例如，在新兴的WiMAX和UMTS-LTE无线网络的背景下。联合问题还包含作为特殊情况的单组多播波束成形。后者（因此也是前者）是NP难的。这促使追求计算效率的准最优解决方案。结果表明，拉格朗日松弛加上适当的随机化/同信道多播功率控制产生计算效率高质量的近似解。对于很大一部分问题实例，这种方式生成的解决方案是最优的。使用模拟和测量的无线信道提供了大量的数值结果来证实我们的主要发现。
The problem of transmit beamforming to multiple cochannel multicast groups is considered, when the channel state is known at the transmitter and from two viewpoints: minimizing total transmission power while guaranteeing a prescribed minimum signal-to-interference-plus-noise ratio (SINR) at each receiver; and a "fair" approach maximizing the overall minimum SINR under a total power budget. The core problem is a multicast generalization of the multiuser downlink beamforming problem; the difference is that each transmitted stream is directed to multiple receivers, each with its own channel. Such generalization is relevant and timely, e.g., in the context of the emerging WiMAX and UMTS-LTE wireless networks. The joint problem also contains single-group multicast beamforming as a special case. The latter (and therefore also the former) is NP-hard. This motivates the pursuit of computationally efficient quasi-optimal solutions. It is shown that Lagrangian relaxation coupled with suitable randomization/cochannel multicast power control yield computationally efficient high-quality approximate solutions. For a significant fraction of problem instances, the solutions generated this way are exactly optimal. Extensive numerical results using both simulated and measured wireless channels are presented to corroborate our main findings.