A primary access node adds a secondary access node to deliver wireless communication service to a User Equipment (UE). The primary access node comprises baseband circuitry and a radio. The radio wirelessly receives a measurement report from the UE that characterizes a radio metric for the secondary access node. The baseband circuitry determines insertion loss for the secondary access node and an add threshold for the secondary access node based on the insertion loss. The baseband circuitry determines an add value for the secondary access node based on the radio metric. When the add value exceeds the add threshold, the baseband circuitry transfers network signaling to the secondary access node to serve the UE and transfers user signaling to the UE over the radio. The UE attaches to the secondary access node and the secondary access node delivers the wireless communication service to the UE.

One or more processors, operating in a source base station and/or a target base station, determines a change in the termination point from the source base station to the target base station for a radio bearer with a current count value according to data unit sequencing. The one or more processors determine (1806) whether a user equipment (UE) changes the data unit sequencing as a result of the change in the termination point. In a first instance, the one or more processors cause the target base station to apply (1810) the current count value to the radio bearer, in response to determining that the data unit sequencing does not change. In a second instance, the one or more processors cause the target base station to apply (1820) a new count value different from the current count value to the radio bearer, in response to determining that the data unit sequencing changes.

Methods and apparatus for radio resource measurement (RRM) at a user device between two wireless communication systems, the method including obtaining an RRM configuration from a first base station (BS) in a first wireless communication system, sending the RRM configuration to a second BS in a second wireless communication system, receiving, from the second BS, a request for a measurement report, triggering a measurement in the first wireless communication system based on the RRM configuration, and sending the measurement report to the second BS. The measurement report includes a measurement result obtained from the triggered measurement.

A communication technique for synchronizing a set of radio nodes is described. In this communication technique, the radio node arbitrates (e.g., using a precision time protocol or PTP) with the other radio nodes based on a selection technique to select a synchronization master in the set of radio nodes. This synchronization master may be selected to have a predefined performance based on a type of communication environment of the set of radio nodes. For example, the type of communication environment may include overlap between at least one of the radio nodes in the set of radio nodes and a macrocell in a cellular-telephone network, or may exclude overlap between the set of radio nodes and the macrocell. Moreover, the synchronization master may specify time, frequency, and phase synchronization for the set of radio nodes. Thus, when the synchronization master is different from the radio node, the radio node synchronizes with the synchronization master.

A gateway for X2 interface communication is provided, including: an X2 internal interface for communicating with, and coupled to, a plurality of radio access networks (RANs); and an X2 external interface for communicating with, and coupled to, a destination outside of the plurality of RANs, the X2 external interface further including a single X2 endpoint for the plurality of radio access networks, such that the X2 external interface provides a single interface for an external macro cell or core network to interact with the plurality of radio access networks. The gateway may further include a handover module for maintaining X2 signaling associations and transactions for incoming and outbound handovers, including X2 to S1 and S1 to X2 translation.

Provided are a handover method and device involving multiple core networks. The method includes: transmitting, by a first base station, a handover request message to a second base station directly transmitting or through a core network; receiving, by the first base station, a feedback message from the core network or the second base station, where the feedback message carries at least one of: information about a core network suggested to be handed over, a failure reason.

Example communication methods and apparatus are described. In one example method, a first access network device obtains core network load information, where the core network load information indicates at least one of load of a first core network element or load of a second core network element. The first access network device determines, from the first core network element and the second core network element based on the core network load information, a core network element serving a terminal device.

In order to prevent deterioration of QoE of a user in intersystem handover, an apparatus according to the present invention includes: an information obtaining unit configured to obtain network slice related information related to a network slice used by a terminal apparatus in a first radio communication system; and a first communication processing unit configured to transmit, to a second network node of a second radio communication system, a message for intersystem handover of the terminal apparatus from the first radio communication system to the second radio communication system, the message including the network slice related information.

Provided in implementations of the present disclosure is a wireless communication method. The method comprises: a terminal device judges whether a first cell or first frequency point supports a cell or a frequency point accessed by the terminal device; and when the first cell or first frequency point supports the cell or the frequency point accessed by the terminal device, the terminal device measures the first cell or first frequency point, and/or reports the measurement result of the first cell or first frequency point.

Aspects of the present disclosure relate to wireless communications, and more particularly, to mobility techniques that allow for dynamically updating a set of cells activated to serve a user equipment (UE) and the cell in the set of cells designated as the primary cell (PCell). An example method includes receiving signaling indicating a set of cells supported by one or more distributed units (DUs) under a common central unit (CU); identifying a subset of the set of cells activated to serve the UE, wherein a first cell of the activated cells comprises a primary cell selected from cells included in a candidate set of primary cells (PCells); and identifying another one of the activated cells to serve as the PCell if the first cell is re-designated as a secondary cell (SCell), wherein the other one of the activated cells comprises a cell selected from the candidate set of PCells.