Rate Balancing in Multiuser MIMO OFDM Systems
Rate Balancing in Multiuser MIMO OFDM Systems
复制标题
多用户 MIMO OFDM 系统中的速率平衡
DOI：
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发表时间：
2009
影响因子：
8.3
通讯作者：
G. Bauch
中科院分区：
文献类型：
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作者：
P. Tejera;W. Utschick;J. Nossek;G. Bauch
最近，高斯广播信道的容量区域已经被表征。对于给定的发射功率约束，在容量区域的边界上的那些点可以被视为最优操作点的集合。目前的工作解决的问题，在这一组内，满足给定的约束条件，在网络中的不同用户实现的速率之间的比率选择点。这个问题通常被称为速率平衡。为此，一般MIMO信道的最佳迭代方法被重新审视，并适用于OFDM传输方案。具体而言，提出了一种算法，利用OFDM信道的结构，其收敛速度基本上是不敏感的子载波的数量。这与一般MIMO算法到OFDM方案的直接扩展形成对比。尽管如此，相对较高的复杂性和需要一个分时政策，以达到一定的速度至少是两个障碍的实际实施的最佳解决方案。基于一种新的广播信道分解技术，引入了一种次优非迭代算法，该算法不需要分时，非常接近最优解。
Recently, the capacity region of the Gaussian broadcast channel has been characterized. For a given transmit power constraint, those points on the boundary of the capacity region can be regarded as the set of optimal operational points. The present work addresses the problem of selecting the point within this set that satisfies given constraints on the ratios between rates achieved by the different users in the network. This problem is usually known as rate balancing. To this end, the optimum iterative approach for general MIMO channels is revisited and adapted to an OFDM transmission scheme. Specifically, an algorithm is proposed that exploits the structure of the OFDM channel and whose convergence speed is essentially insensitive to the number of subcarriers. This is in contrast to a straightforward extension of the general MIMO algorithm to an OFDM scheme. Still, relatively high complexity and the need of a time-sharing policy to reach certain rates are at least two obstacles for a practical implementation of the optimum solution. Based on a novel decomposition technique for broadcast channels a suboptimum non-iterative algorithm is introduced that does not require time-sharing and very closely approaches the optimum solution.