In the inter-site DC solution, the X2 interface can be used to implement transmission interconnection...

The X2 interface is a signaling interface used in LTE networks to interconnect two eNodeBs (LTE base stations) to support handover and other functions. In the inter-site DC solution, the X2 interface can also be used to implement the transmission interconnection between the LTE and NR sites.

In order to ensure smooth handover and service continuity between the LTE and NR sites, it is necessary to meet the requirement of low transmission delay, which is typically <20ms. This low delay requirement is important to ensure that the handover can be completed quickly and without interruption to the ongoing service.