Cooperative Detection and Spectrum Reuse using a Network Coded Cognitive Control Channel

Among the major challenges in the development of effective dynamic spectrum access techniques are the realization of the control channel, the detection of primary users, and the efficient use of the available spectrum. Most of the previous work in this field has addressed only a subset of these issues. In a previous paper we proposed a distributed multi-channel medium access strategy based on a network coded cognitive control channel (NC⁴), which addresses the issues of the control channel and the spectrum efficiency. In this paper we apply that solution to dynamic spectrum access scenarios. The key feature of this work is the introduction of a cooperative primary user detection strategy which effectively enables the detection and reuse of unused portions of the licensed spectrum. The complete system resulting from this extension, which we call NC⁴-DSA, has the merits of being fully distributed, not requiring spectrum resources statically allocated for control purposes, and being very suitable for implementation thanks to the use of simple and low cost detection strategies such as energy detection. Furthermore, as we will show in our performance evaluation, it enables efficient opportunistic spectrum access with minimal interference to primary users.