How network coding helps eMBMS

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. Recently, network coding schemes have been proposed for wireless multicast. In this paper, we study how network coding can be used in practical eMBMS system. After analyzing the system architecture and function, we find that NC based FEC scheme implemented at eBMSC is the best way to exploit NC gain. However existing NC based FEC schemes are not suitable for eMBMS system because they don´t consider the redundancy generated at the source node and the packet loss rate in wireless channel. In this paper, we propose an adaptive degree selection scheme to improve the LT performance in terms of the error recovery rate and decoding delay. Experimental results confirm significant performance improvement.