On the Capacity Region for Cognitive Multiple Access Over White Space Channels
Cognitive Radio (CR) has stirred great interest with its potential to exploit the already scarce spectrum resource. The Cognitive Multiple Access Channels (CogMAC) are commonly seen in many applications, such as the Cognitive Radio Sensor Networks (CRSN), and the 802.22 cognitive Wireless Regional Area Networks (WRAN). In this paper, the Primary User (PU) activities are treated as on/off side information, which can be obtained causally or non-causally. The cognitive MAC channels are then modeled as multi-switch channels and their rate regions are characterized. Explicit forms of outer and inner bounds of this rate region are derived by assuming additional side information, and they are shown to be tight in some special cases.