A Software Defined Radio Based Adaptive Interference Avoidance TDCS Cognitive Radio

In this paper, we implement and demonstrate an adaptive interference avoidance TDCS (Transform-domain Communication System) based cognitive radio via software defined radio implementation. By dynamically notching the occupied bands prior to applying IDFT, the designed cognitive radio communicates without interference to primary users and from primary users, as well as provides coexistence between primary users and secondary users. The designed system applies GNU software radio as the platform, and USRP (Universal Software Radio Peripheral) as the hardware solution. This cognitive radio is capable of detecting primary users in real time and adaptively adjusting its transmission parameters to avoid interference to primary users. Additionally, we have demonstrated that when the primary user transmission changes, the cognitive radio dynamically adjusts its transmission accordingly. We have demonstrated seamless real time video transmission between two cognitive radio nodes, while avoiding interference from primary users and interference to primary users operating in the same spectrum.