I. Introduction
With the surging deployment of wireless communication devices and the emergence of software-defined radios, the shortage of radio spectrum is becoming a more and more serious problem. On the one hand, each protocol in the IEEE 802.11 [1] standard specifies a number of overlapping wireless channels, among which only limited number of orthogonal channels are available (e.g., 3 orthogonal channels in IEEE 802.11b/g and 12 in IEEE 802.11a). On the other hand, traditional static allocation of the wireless channels hinders the already limited spectrum resource from being used efficiently [2]–[4]. Hence, considering the insufficient usage of current available wireless channels, it is highly important to carefully allocate the wireless channels, in order to promote the performance of wireless networks.