I. Introduction
Resource allocation, such as power control, has long been regarded as an effective way of dynamically combating channel fluctuations and reducing cochannel interference in wireless networks. The power control constantly adjusts the transmit power to maintain the received link quality, while improving the system performance. In some applications, such as wireless sensor networks in which each user is powered by batteries, optimizing the power management can greatly extend the network lifetime. Much work has been done for resource allocation for multiuser wireless networks. In [1], the authors gave an overview of radio resource management for wireless networks. In [2] and [3], a closed-loop power control framework was proposed and proved to converge to a unique optimal point. In [4], a second-order power control algorithm was proposed to improve the convergence speed. In [5], rate adaption and power control were combined to increase the system throughput. In [6] and [7], power control was combined with antenna array processing to improve the network performance. In [8], an algorithm considering time, space, and multiuser diversity was proposed for enhancing the system efficiency.