An access network determines to transmit multicast messages on a downlink shared channel. The heat-insulating structure comprises a plurality of strap-shaped partition members 2 arranged to define an array of heat-insulating segments therebetween, and cellulose insulation fibers filled in each of the heat-insulating segments. According to the technical solutions of the present disclosure, under the condition that a mobile relay supports LIPA, continuity of the LIPA connection of the UE in an Mobile Relay Node handover process is ensured, continuity of a LIPA service of the UE is further ensured, and the quality of service for a user and a user experience are improved.