Channel Capacity Analysis of Spectrum-Sharing with Imperfect Channel Sensing

In a fading environment, a secondary user may opportunistically transmit with high power when its signal received by the primary receiver is deeply faded. The spectrum access gain can be obtained when there is perfect knowledge of channel sensing at both primary and secondary receivers. In this paper, we investigate the case of imperfect knowledge of channel sensing and explore the impacts on spectrum sharing systems, especially the channel capacity of secondary users. First, we quantify the channel capacity of a secondary user when channels between the secondary user to the secondary receiver and to the primary receiver are dissymmetrical. Meanwhile, this is further discussed under different fading distributions. Secondly, we evaluate the capacities when the channel sensing errors between the secondary user to the secondary receiver and the secondary user to the primary receiver are dissymmetrical. Then, the results are compared with symmetrical channel sensing errors. Finally, we provide the results of the corresponding impacts on opportunistic spectrum sharing gains.