The present invention presents a method for small cell communications, comprising: MME transmits a message of setting up a user plane for UE to a base station in a small cell cluster of the UE, wherein the messages of setting up a user plane include information about evolved radio access bearer as well as uplink tunnel identity and address of the transport layer assigned by SGW; the base station assigns downlink TEID and address of the transport layer to the UE, and responds to the MME; the MME transmits the downlink TEID and the address of the transport layer assigned to the UE to the SGW that serves the UE, and receives a response message from the SGW. Examples of the present invention further present an MME device, a base station device, an SGW device and a small cell communication system. The above scheme presented by the present invention provides a method of supporting the architecture and data transmission of small cells, which supports quick handover between small cells, reduces data loss during the handover, avoids multi-hop data forwarding, guarantees QoS, and improves user experience and system performance.