Joint Power Control and Channel Assignment for Green Device-to-Device Communication

The Device-to-Device (D2D) communication allows two user devices to communicate directly without passing through the Base Station (BS). Most of the existing researches for green D2D communications try to achieve the minimum total transmission power of all user devices by performing resource allocation (i.e. channel allocation) first, and then performing power allocation according to the QoS requirement of each user device so as to save energy. However, after power allocation, the original allocated channel may not be the most energy efficient for the user device. To improve the existing works, we propose a novel green D2D communication scheme which combine the power allocation and channel reallocation so as to further reduce the total transmission power of all user devices. In the proposed scheme, the channel of each user device is reallocated after the first turn of power allocation to find if there is any channel reallocation can further reduce the transmission power of user devices and still satisfy the QoS requirement. The channel reallocation and power control proceeds until no further reduction of transmission power is possible. Note that, the channel and power are not really allocated to the user devices until the final allocation results are calculated by the base station. Simulation results show that the proposed scheme can save about 18.4% power as opposed to the existing schemes.