Optimal non-identical sensing setting for multi channels in cognitive radio networks

In this paper, optimal multiple channels cooperative spectrum sensing setting in non-identical environment is investigated. In previous works on cooperative sensing, the secondary users are assumed to have the same detection threshold and the noise received is assumed to be independent identically distributed random variable. Thus researchers often assume that identical sensing time is assigned to the channels for spectrum sensing. In our paper, secondary users cooperatively sense the channel and send the binary results to the common receiver where energy detection with hard decision rule is employed. We assume that secondary users can assign non-identical sensing time to the channel with possibly different noise powers and detection thresholds. An iterative algorithm with polynomial complexity is established to determine the optimal sensing sequence (which represents the order at which the secondary users sense the channels) for the secondary users to assign the mini-slots (minimum sensing unit) to sense the channels, such that the throughput increase can be maximized in each iteration. Furthermore, delay sensitivity is introduced as a new performance metric to evaluate how long the authorized transmitting users need to wait for data transmission. Simulation results show that our algorithm is highly effective in improving the achievable throughput and delay sensitivity.