Joint feedback design in rateless coded multi-user MISO cognitive radio networks

In this paper, we propose a joint spectrum sensing and spectrum access tradeoff framework for a multi-user multiple-input single-output (MISO) cognitive radio network with limited feedback in order to improve spectrum efficiency. Firstly, we reduce the feedback information of requests for data retransmission by employing the recently developed incremental redundancy channel code, namely rateless code, for the data transmission of secondary users. Then by jointly considering the effects of multi-user cooperative sensing and multi-user MISO beamforming to the system performances, we propose a feedback bit allocation method for both the spectrum sensing results and the quantized channel state information under a sum feedback amount constraint, so as to maximize the throughput of cognitive radio network while protecting primary user from interference. Finally, simulation results are shown to validate the effectiveness of our proposed method.