Dual methods for nonconvex spectrum optimization of multicarrier systems
Dual methods for nonconvex spectrum optimization of multicarrier systems
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DOI：
10.1109/tcomm.2006.877962
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发表时间：
2006-07-01
影响因子：
8.3
通讯作者：
Lui, Raymond
中科院分区：
文献类型：
--
作者：
Yu, Wei;Lui, Raymond
多载波通信系统的设计和优化通常涉及对系统资源约束的总吞吐量的最大化。当问题没有凸结构时，优化问题在数值上很难解决。本文通过表明在某种称为时间共享条件的条件下，在解决这种类型的优化问题方面取得了进展，无论目标函数的凸度如何，优化问题的双重性差距始终为零。此外，我们表明，用于实用的多频谱优化满足时间共享条件。随着载体数量到达无穷大的数量，多载波系统中的问题。该结果导致有效的数值算法可以解决双重域中的非凸问题。我们表明，最近提出的用于数字订户系列的最佳频谱平衡算法可以解释为双重算法。这种新的解释产生了更有效的双重更新方法。它还提出了可以大致评估双重目标的方法，从而进一步提高了算法的数值效率。我们提出了基于这些思想的低复杂性迭代频谱平衡算法，并表明新算法在许多实际情况下实现了近乎最佳的性能。
The design and optimization of multicarrier communications systems often involve a maximization of the total throughput subject to system resource constraints. The optimization problem is numerically difficult to solve when the problem does not have a convexity structure. This paper makes progress toward solving optimization problems of this type by showing that under a certain condition called the time-sharing condition, the duality gap of the optimization problem is always zero, regardless of the convexity of the objective function. Further, we show that the time-sharing condition is satisfied for practical multiuser spectrum optimization. problems in multicarrier systems in the limit as the number of carriers goes to infinity. This result leads to efficient numerical algorithms that solve the nonconvex problem in the dual domain. We show that the recently proposed optimal spectrum balancing algorithm for digital subscriber lines can be interpreted as a dual algorithm. This new interpretation gives rise to more efficient dual update methods. It also suggests ways in which the dual objective may be evaluated approximately, further improving the numerical efficiency of the algorithm. We propose a low-complexity iterative spectrum balancing algorithm based on these ideas, and show that the new algorithm achieves near-optimal performance in many practical situations.