Cognitive radio implementation in ISM bands with Microsoft SORA

Cognitive radio network research has mostly focused on licensed spectrum sensing and empty spectrum use while protecting licensed band primary users. However, the wide deployment of WiFi access points in unlicensed bands in urban areas brings difficult challenges regarding co-existence of ad hoc mobile users with residential access points. In this paper, we propose a new mobile user protocol for dynamic channel selection via channel workload estimation. The mobile node senses channel usage in unlicensed ISM band and selects the maximum residual capacity channel for own packet transmission. The new protocol is implemented on Microsoft´s SORA software defined radio system that enables fast prototyping. We have evaluated the performance using a Campus deployed SORA testbed. Experimental results show the efficiency of our approach in avoiding external interference.