Speaker: Mohammad Robat Mili, Date: 18th of December 2015, Time: 13:30, Room: 201 (DEI/A)
Abstract. In this talk, I will explain how to allocate the optimum power transmission in cognitive radio and femtocell networks. In a cognitive radio scenario which consists of primary users and secondary users, secondary users are allowed to opportunistically access the existing spectrum without adverse effect on primary users.A cognitive radio network is allowed to detect its communication environment, replace the parameters of its communication scheme to raise the quality of service for secondary users and decrease the interference to primary users. Alternatively, the other approach to implementing a cognitive radio network is to allow simultaneous transmission of primary users and secondary users, which is also termed as spectrum sharing. In this technique, a secondary transmitter can transmit while its maximum interference to the primary receiver is smaller than the predefined threshold. However, a secondary user must control its transmit power to get a reasonable transmission rate. In spectrum sharing approach, we will introduce maximization of the ergodic capacity under different constraints at the primary users. The effect of reducing channel side information at the secondary transmitter is discussed. The next part of this presentation is concerned with the optimal power allocation in femtocell networks using a new technique based on multiobjective optimization.