On Randomized Sensing and Access Schemes in Wireless Ad-Hoc Cognitive Networks

Abstract: Over the past decade we have witnessed a rapid growth and development in wireless communication systems, to the point that conventional spectrum allocation policies may not be able to fulfill them all. Federal Communications Commission (FCC) licenses certain frequency segments to a particular user in a particular geographic area. Industrial, Scientific and Medical (ISM) radio bands have also been envisioned for all other unlicensed user to share, as long as they follow certain power regulations. But with the recent boom in the wireless technologies, these open channels have become overcrowded with everything from wireless networks to wireless controllers. Therefore, the regulatory and standardization agencies have been working on new spectrum regulation policies for wireless communication systems. The underlying idea is to let unlicensed users to use the licensed band as long as they can guarantee low interference to the licensed users. Though seemingly simple, sophisticated interference management protocols are needed to meet the expected level of transparency accepted by licensed users. In this report we adopt the dynamic spectrum access approach to limit the interference to primary users and analyze the performance of the cognitive MAC protocols based on randomized sensing and access schemes.