A Novel Transmission Policy for Reliable eMBMS Download Delivery

Enhanced Multimedia Broadcast/Multicast Service (eMBMS) is a new function defined in 3GPP Release 8 specification, which supports download delivery and streaming delivery to group users in LTE mobile networks. For download delivery, there are two mechanisms implemented in different entities to improve reliability: (1) At eBMSC (Enhanced Broadcast/Multicast Service Center), Raptor code is implemented in software to provide packet-level protection in the application layer; (2) At eNB (Enhanced NodeB), HARQ is used to provide bit-level protection in the link-layer. In this paper, we first analyze the redundancy caused by the coexistence of HARQ and Raptor, and then propose a novel HARQ retransmission policy to reduce the redundancy. Simulation results, using the Matlab and OPNET, confirm significant improvement.