Efficient network coding scheme for disjoint clusters of D2D networks and cellular communications

摘要

This paper considers a broadcast scenario where a base station seeks to transmit a common content to a group of users. Due to impairments inherent to broadcast channels, transmitted content may be partially received by the users, thereby requiring retransmissions to recover missing parts of the content. The retransmission process can be optimized by leveraging instantly decodable network coding (IDNC) with the help of disjoint clusters of combinations of single-hop fully connected and/or multi-hop partially connected device-to-device (D2D) network configurations. This paper aims to find an efficient encoding strategy for the broadcasted packets that minimizes the packet completion time problem, defined as the number of transmission slots necessary to satisfy the demand of all users. To this end, we design an efficient mechanism, LoCoNCDC, which enables us to find feasible codes that can be transmitted by the base station via cellular links. Moreover, the proposed LoCoNCDC permits us to identify the set of transmitting D2D users along with the corresponding IDNC packets that the transmitting users can broadcast through D2D links. Furthermore, we theoretically characterize the performance bound of the proposed approach. Finally, the efficiency of the proposed LoCoNCDC is validated through numerical results which demonstrate substantial performance gain compared to existing schemes.