Abstract: The present disclosure provides a method in a secondary Base Station (BS) for reporting a downlink data transmission state to a master BS. The method comprises: transmitting, by the secondary BS, one or more Packet Data Convergence Protocol (PDCP) Protocol Data Units (PDUs) from the master BS to a User Equipment (UE); and transmitting, by the secondary BS, to the master BS a downlink data transmission state message including a sequence number of at least one PDCP PDU that has been transmitted successfully. The present disclosure also provides a method in a master BS for discarding PDCP PDUs as early as possible. The method comprises: receiving, by the master BS, from a secondary BS a downlink data transmission state message; and discarding, by the master BS, one or more PDCP PDUs stored in the master BS based on the downlink data transmission state message. The associated master BS and secondary BS are also provided.

Abstract: The present disclosure provides a method and an apparatus for implementing a subscription notification. The method includes: receiving a subscription resource creation request of a subscriber; creating a subscription resource according to the subscription resource creation request; determining that the subscriber needs to acquire a latest status of the subscribed resource, and allocating a latest status identifier to the created subscription resource; and when a status of the subscribed resource is updated, generating a notification message according to the subscription resource, and sending the notification message to an intermediate node, where the notification message includes the updated status of the subscribed resource and the latest status identifier which indicates that when a message sending condition is met, only a latest notification message is sent.

Abstract: Embodiments of the present invention provide a group communication method, system, group server, and group member device. A group server receives notification messages sent by a group member device, aggregates, according to an address of a subscription device, the notification messages destined for the same subscription device, and sends a notification message obtained after aggregation to the subscription device. By aggregating multiple messages sent by the group member device to the subscription device, messages exchanged between the group member device and the subscription device are reduced, thereby reducing communication traffic between the group member device and the subscription device.

Abstract: The present invention provides a method, an apparatus, and a system for securely transmitting data. A method for securely transmitting data is provided, where the method includes: sending, by a user terminal, a resource access request carrying a first authentication header field to a server, where the first authentication header field includes a user identifier and a server identifier; and receiving a request response returned by the server, where the request response includes a second authentication header field and a message body, where the second authentication header field carries a third integrity digest, and the third integrity digest is obtained by the server by performing, after receiving the resource access request, calculation by using a third message-digest algorithm further according to a user password and message content; so that M2M transmission based on the CoAP protocol can be performed securely and reliably.