Cooperative transmission for cognitive radio networks using mutual-information accumulation

In cognitive radio networks, secondary users (SUs) have to control their transmission power so that the interference to primary users´ (PUs) are tolerable. Under this situation, SUs will transmit at a relatively low power level experiencing high bit error rate with limited coverage range. To address this problem, cooperative transmission using mutual information accumulation is introduced to cognitive radio networks. To be specific, resource allocation problem in such a network is investigated and is factored into two sub-problems, each of which can be solved efficiently. The simulation results show that mutual information accumulation can significantly decrease the delay of a cognitive radio network especially in the scenario where the PU has a tight interference power constraint.