On the Link Scheduling for Cellular-Aided Device-to-Device Networks

We consider a cellular-aided inband overlay device-to-device (D2D) network, where a base station (BS) and all devices share a frequency band for their communications, but the BS allocates dedicated radio resources to D2D direct communications to avoid the mutual interference between D2D and cellular communications. We first mathematically formulate the optimal sum rate of the D2D network, and provide closed-form approximations of the average sum rate for low and high signal-to-noise ratio (SNR) regimes. Furthermore, we propose two practical D2D link scheduling algorithms: centralized and distributed. The centralized algorithm reduces the computational complexity at the BS, and its performance is shown to be optimal since the SNR of D2D links tends to be either zero or infinity. The distributed algorithm significantly reduces the signaling overhead caused by channel state information feedback from devices to the BS, and the performance loss of the distributed algorithm is marginal compared with that of the centralized algorithm, particularly when the number of D2D pairs is small.