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arXiv 0810.1234cs.ITcs.NImath.ITmath.OC
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衰落多址信道中的资源分配--一种有效的近似投影方法

On Resource Allocation in Fading Multiple Access Channels - An Efficient Approximate Projection Approach

Ali ParandehGheibi, Atilla Eryilmaz, Asuman Ozdaglar, Muriel Medard

摘要:

我们考虑在多址接入信道的速率和功率分配问题。我们的目标是获得速率和功率分配政策,最大限度地提高了一般凹效用函数的平均传输速率的信息理论容量区域的多址信道。我们的政策并不要求提供篇幅过长的信息。我们考虑几种不同的情况。首先,我们解决效用最大化问题,在非衰落信道中获得最佳的操作速率,并提出了一种迭代梯度投影算法,使用近似投影。通过利用容量区域的多拟阵结构,我们证明了近似投影可以在用户数的时间多项式中实现。其次,我们考虑在衰落信道中的资源分配。最优速率和功率分配策略的情况下,功率控制是可能的,信道统计。对于传输功率固定和信道统计信息未知的情况下,我们提出了一种贪婪的速率分配策略,并提供了该策略的性能差异和最优策略的信道变化和结构的效用函数的界限。我们提出的数值结果表明,优越的收敛速度性能的贪婪的政策相比,基于长度的政策。为了降低贪婪策略的计算复杂性,本文提出了一种近似的速率分配策略,该策略在一定的邻域内跟踪贪婪策略,该邻域的特征在于衰落速度。

英文摘要:

We consider the problem of rate and power allocation in a multiple-access channel. Our objective is to obtain rate and power allocation policies that maximize a general concave utility function of average transmission rates on the information theoretic capacity region of the multiple-access channel. Our policies does not require queue-length information. We consider several different scenarios. First, we address the utility maximization problem in a nonfading channel to obtain the optimal operating rates, and present an iterative gradient projection algorithm that uses approximate projection. By exploiting the polymatroid structure of the capacity region, we show that the approximate projection can be implemented in time polynomial in the number of users. Second, we consider resource allocation in a fading channel. Optimal rate and power allocation policies are presented for the case that power control is possible and channel statistics are available. For the case that transmission power is fixed and channel statistics are unknown, we propose a greedy rate allocation policy and provide bounds on the performance difference of this policy and the optimal policy in terms of channel variations and structure of the utility function. We present numerical results that demonstrate superior convergence rate performance for the greedy policy compared to queue-length based policies. In order to reduce the computational complexity of the greedy policy, we present approximate rate allocation policies which track the greedy policy within a certain neighborhood that is characterized in terms of the speed of fading.

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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