The present disclosure relates to a communication method and system for converging a 5th-Generation (5G) communication system for supporting higher data rates beyond a 4th-Generation (4G) system with a technology for Internet of Things (IoT). The present disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. The disclosure provides a method and device for switching a serving cell.

A method and system for controlling air-interface connectivity of a user equipment device (UE). A computing system detects, when the UE has dual connectivity including a first air-interface connection with a first access node and a second air-interface connection with a second access node, and when the first air-interface connection is defined on a first carrier, that the UE is moving toward a geographic area where UEs that were served by the first access node on the first carrier as part of dual connectivity lost their dual connectivity due to their having insufficient aggregate dual-connectivity throughput. And based at least on the detecting, the computing system reconfigures the first air-interface connection of the UE's dual connectivity to be defined on a lower-frequency second carrier, to help avoid having the UE lose its dual connectivity.

Systems and methods are contemplated for reconfiguration of one or more MAC instances while the WTRU is operating using dual- or multi-MAC instance connectivity. For example, upon reception of RRC reconfiguration information that modifies one or more secondary MAC instances, the WTRU may transmit a reconfiguration complete message to a Macro eNB (MeNB) and may synchronize to small-cell or secondary eNB (SeNB), for example if triggered by one or more of an RRC flag, a physical downlink control channel (PDCCH) order (MeNB/SeNB), MAC activation information, etc. For example, the WTRU may synchronize to the SeNB for specific type(s) of RRC reconfigurations, but not other type(s) of RRC reconfigurations. Although examples may be described in terms of dual connectivity, the WTRU may establish connectivity and perform mobility procedures with more than two radio access network (RAN) nodes (e.g., eNBs), and the embodiments described may be equally applicable to those scenarios.

An embodiment of the present disclosure may provide an inter-MeNB handover method in a small cell system, including: making, by a source MeNB and/or target MeNB, a determination as to whether to maintain a SeNB when handover is performed; and triggering different handover processes according to a result of the determination as to whether to maintain the SeNB. Another embodiment of the present disclosure may further provide an inter-MeNB handover device in a small cell system. With the inter-MeNB handover method and device in a small cell system provided by the present disclosure, unnecessary deletion and re-establishment of the bearers at the SeNB for the UE may be reduced. False bearer deletion may be avoided and data forwarding may be reduced. Furthermore, the SeNB may be maintained according to network deployment and SGW re-selection may be supported. Therefore, system capacity and transmission speed of the data may be improved.

A method (400) for reporting radio link failure, RLF, information. The method includes a user equipment, UE, detecting (s402) an RLF with respect to a master cell group, MCG. The method also includes, in response to detecting the RLF with respect to the MCG, the UE storing (s404) RLF information. The method also includes the UE sending (s406) a first message comprising MCG failure information, e.g., the RLF information, and activating a timer. The method also includes the UE receiving (s408) a second message after sending the first message and activating the timer. The method also includes the UE, in response to receiving the second message, determining (s410) that a condition is satisfied, wherein determining that the condition is satisfied comprises at least determining that the timer is still running. The method also includes, as a result of determining that the condition is satisfied, the UE deleting (s412) the RLF information.

The present disclosure relates to a method and apparatus for transmitting and receiving data in a wireless communication system. An operating method of a terminal that is able to communicate with a master node and a secondary node in a wireless communication system includes detecting a master cell group (MCG) failure related to the master node, in response to the detecting of the MCG failure, changing a primary path of a split signaling radio bearer 1 (SRB1) from a radio link control (RLC) bearer of an MCG related to the master node to one RLC bearer from among a plurality of RLC bearers of a secondary cell group (SCG) related to the secondary node, based on a pre-determined criterion, and transmitting a message related to the MCG failure to the master node, by using the RLC bearer of the SCG changed as the primary path.

The present disclosure provides an information transmission method, an information reception method and apparatuses. The information transmission method includes: recording, by a UE, information related to CHO and/or CPC; and transmitting, by the UE, the information related to the CHO and/or CPC to a network.

The present disclosure relates to handling a secondary cell group (SCG) failure in wireless communications. According to an embodiment of the present disclosure, a method performed by a wireless device in a wireless communication system comprises: receiving, from a source primary secondary cell (PSCell), a conditional mobility command including a mobility condition for a target PSCell; initiating a secondary cell group (SCG) failure recovery procedure and transmitting SCG failure information related to the SCG failure recovery procedure to a primary cell (PCell), based on detecting an SCG failure related to the source PSCell: based on that the mobility condition for the target PSCell is satisfied during the SCG failure recovery procedure: transmitting, to the PCell, a new PSCell indication informing a mobility from the source PSCell to the target PSCell; and performing a random access to the target PSCell for the mobility.

A communication method, an apparatus, and a communications system. A terminal device receives first configuration information. In response to an RLF occurring in a source MCG or a source SCG of the terminal device, the terminal device sends a first message including information about a time period from the terminal device receiving the first configuration information to the radio link failure occurring in the source MCG or the source SCG, or information about a time period from the RLF occurring in the source MCG or the source SCG to the terminal device sending the first message. In this way, a network device exchanges proper and valid information between network devices based on the information reported by the terminal device, to optimize parameters.

Example embodiments of the present disclosure relate to devices, methods, apparatuses and computer readable storage media for a primary secondary cell (PSCell) change failure. In example embodiments, a master network device receives, from a source secondary network device, a first request for a change of a terminal device from the source secondary network device to a target secondary network device. The master network device receives, from the source secondary network device, an identification of a source PSCell operated by the source secondary network device and serving the terminal device prior to the first request. The master network device further receives, from the terminal device, an indication of a radio link failure of the terminal device in a PSCell and transmits the indication of the radio link failure to the source secondary network device along with the identification of the source PSCell.