Simulating dynamic spectrum access using ns-3 for wireless networks in smart environments

Sudden spectrum demands may occur in dense and congested cities, which stress the communication infrastructure. At these times, identifying alternate spectrum bands through cognitive radio (CR) technology will allow users to maintain connectivity and relieve data congestion in the unlicensed bands. However, deployment of the CR networks must be preceded by accurate simulation of these networks, given the high infrastructure costs involved in their installation. Moreover, CR protocols are often cross-layered, which cannot be trivially implemented in off-the-shelf hardware. This paper proposes a framework for the network simulator 3 (ns-3) that is suitable for large networks. Our approach introduces several CR capabilities, such as spectrum sensing, primary user detection, and spectrum hand-off. Our simulator demonstrates improvements in execution time and memory usage, when compared to the earlier versions implemented for the ns-2 environment. This paper is accompanied by the release of the full source code for further research and improvement.