Network Coding for Wireless Ad Hoc Cognitive Radio Networks

A cognitive radio network (CRN) is often described as a secondary communication network operating in a frequency band originally allocated to a primary network consisting of one or multiple primary users (PUs). In this paper, we consider a wireless ad hoc network as a CRN, which coexists with multiple geographically distributed PUs. A novel approach based on network coding is proposed for wireless multicast in CRNs to improve the throughput of the secondary network with minimum energy-per-bit, while protecting the PUs. Under interference power constraints for PUs, and signal-to-interference- plus-noise ratio (SINR) constraint for each transmission, we formulate the minimum-energy multicast in CRNs problem as a linear optimization, which is much easier to solve compared to the NP-hard problem associated with the routing solution. Computer simulations are presented to evaluate the performance gains achieved by the proposed technique in terms of network throughput as well as energy efficiency.