Fully reconfigurable cognitive OFDMA testbed

In this paper, we report our design and implementation of a testbed for demonstration of cognitive OFDMA transmission. Our implementation is based on a powerful fully programmable software radio platform, i.e., the Microsoft Research Software Radio(MRSR) platform. Two kinds of nodes are designed in the testbed, one acts as the primary user(PU) which communicates in the authorized frequency band with dynamic spectrum activity, and the other acts as the secondary user(SU) which opportunistically accesses the vacant frequency without disrupting the transmission of primary user. To this end, the SU nodes are equipped with reliable multi-carrier sensing functionality, as well as some special multi-channel signalling and processing capabilities. Test results show that the SU nodes can alter their power, frequency and other parameters dynamically and communicate efficiently in response to the PU´s spectrum activity.