Sizing X2 Bandwidth for Inter-Connected eNBs

LTE is a next-generation wireless network technology being developed by 3GPP. One unique aspect of LTE is that neighboring eNBs can be directly interconnected through X2 interface to facilitate direct exchange of control messages and to forward user data during handover. In this paper, we investigate the X2 bandwidth requirement for both control-plane traffic and user-plane traffic. We first consider the case where individual UEs cross cell boundaries independently. We then extend to the case where groups of UEs may cross cell boundaries simultaneously. In both cases, we analyze the bandwidth needed on the X2 interface to meet a certain performance objective. Our results generally indicate that the X2 bandwidth requirement is very small compared to Sl-U bandwidth. However, the X2 bandwidth requirement may potentially increase significantly when groups of UEs perform handover simultaneously.