D2D relaying based multicast service in Public Safety Networks

It is a common case in Public Safety Networks (PSNs) that a user equipment (UE) instead of a base station (BS) acts as the multicast transmitter. In the network physical (PHY) layer, we adopt the fountain coding method to reduce network burden and energy consumption of UEs. However, current LTE standards support Quality of Service (QoS) controls only for unicast communications. To satisfy the QoS requirements of emergency group communications, an effective opportunistic multicast scheduling scheme is investigated at the MAC layer which can minimize the delay of a multicast. To further improve multicast throughput, Device-to-Device (D2D) relaying technique is also integrated into the proposed multicast scheduling scheme, which can combat the multicast bottleneck when one or very few receivers are with very poor channel conditions. The simulation results verify the effectiveness of the proposed D2D relaying based multicast service in LTE based PSNs.