Software Defined Radio Implementation of SMSE Based Overlay Cognitive Radio

In this paper, we use a software defined radio to implement the cognitive centric overlay waveform and demonstrate an adaptive interference avoidance cognitive radio. Specifically, we employ the SMSE framework to generate multi-carrier transmission waveforms over non-contiguous frequency bands for the cognitive radio implementation. Combined with a spectrum sensing engine, the cognitive radio detects the availability of each and every subcarrier in the operational bandwidth. By turning off those subcarriers occupied by the primary users, the cognitive radio implements a non-contiguous SMSE transmission. There are a few unique features of our cognitive radio implementation: (1) we have demonstrated real-time seamless video transmission without interference to primary users and from primary users; (2) our cognitive radio is capable of taking advantage of multiple spectrum holes and operating over multiple non-contiguous spectrum bands; (3) the cognitive radio dynamically adjusts which subcarriers to turn off according to the primary users' transmission; (4) the cognitive radio can also easily adjust other parameters such as the total number of subcarriers, center frequency, bandwidth of each subcarrier, and so on, making it a very flexible and robust cognitive radio node.