Power allocation in cognitive spectrum sharing area using effective capacity in imperfect fading channel

In this paper we propose a power control policy over an imperfect fading channel within a cognitive spectrum sharing area. In particular, our proposed scheme maximizes the secondary user effective capacity subject to the average interference power and the secondary user transmit power constraints. We also investigate the minimization of average interference power at the Primary Receiver (PR) under required effective capacity of the secondary user with respect to imperfect Channel State Information (CSI) between cognitive radio transmitter and the PR link. Furthermore the impact of the Quality of Service (QoS) exponent on effective capacity in imperfect channel is studied. The analytical results reveal that the effective capacity of the Secondary User (SU) under given average interference power and peak power constraints increases due to growing channel state error of the secondary transmitter-primary receiver link. Moreover, results show that cross channel error increases the average interference power at the primary receiver with regards to the changing QoS exponent. The numerical analysis confirms our theoretical results.