Design of Downlink Broadcast Channel via Device-to-Device Communications

In this paper, an application of Device-to-Device (D2D) communication as a means of supporting multi-input multi-output (MIMO) downlink broadcast channel in cellular networks is proposed. Devices in the D2D group are arranged to extract their own data originated from a base station (BS) in an order according to a well-scheduled hopping sequence. At each forwarding stage, a best-decode node is selected to decode its own data stream, and then the decoded stream is cancelled from the received vector of the selected node before next transmission. Our design scheme not only provides distributed diversity for the selected nodes but also preserves data information and reduces interference terms for not yet decoded users. Besides, with the cascade of receive vectors in multi-hop transmissions, spatial diversity increases at each incremental hop. Simulation results show that our scheme provides promising diversity gain and therefore also avoids the effect of error propagations compared to traditional schemes.