Matched filter based spectrum sensing and power level recognition with multiple antennas

In this paper, we consider the spectrum sensing problem in a cognitive radio (CR) network with only one primary user (PU) and one secondary user (SU). PU is equipped with single antenna while SU is equipped with multiple antennas. The key different from the conventional spectrum sensing studies is that we assume PU could work on different transmit power levels to cope with different communication environments, which is a more practice-matching model. We also suppose that there is some cooperative mechanism between PU and SU so that SU could know PU´s training symbols during sensing. In the propose scheme, SU needs not only to detect the presence of PU but also to identify PU´s transmit power levels after it is “detected”. Hence, the whole problem is much more challenging than that in conventional CR. We design the matched filter spectrum sensing algorithm by assuming that the channel information is only partially known. Quite a few new performance metrics are provided to better testify the effectiveness of the proposed algorithm in this multiple primary transmit power (MPTP) scenario, and a number of closed-form performance analysis are also derived. Finally simulation results are presented to verify the proposed studies.