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.

The present disclosure relates to a communication scheme and system for converging a 5.sup.th generation (5G) communication system for supporting a data rate higher than that of a 4.sup.th generation (4G) system with an internet of things (IoT) technology. The present disclosure is applicable to intelligent services (e.g., smart homes, smart buildings, smart cities, smart cars, connected cars, health care, digital education, retails, and security and safety-related services) based on the 5G communication technology and the IoT-related technology. The present disclosure provides a method performed by an access and mobility management function (AMF) entity of a visited public land mobile network (VPLMN) in a communication system.

The present disclosure relates to a communication scheme and system for converging a 5.sup.th generation (5G) communication system for supporting a data rate higher than that of a 4.sup.th generation (4G) system with an internet of things (IoT) technology. The present disclosure is applicable to intelligent services (e.g., smart homes, smart buildings, smart cities, smart cars, connected cars, health care, digital education, retails, and security and safety-related services) based on the 5G communication technology and the IoT-related technology. The present disclosure provides a method performed by an access and mobility management function (AMF) entity of a visited public land mobile network (VPLMN) in a communication system.

Methods and apparatuses are provided for activating or deactivating packet duplication in a wireless communication system. A central unit (CU) of a first base station transmits, to a distributed unit (DU) of the first base station, via an F1 interface, information to activate or deactivate a dual connectivity (DC) based packet duplication for a data radio bearer (DRB). The information is transmitted to a second base station. A medium access control (MAC) control element (CE) indicating whether to activate or deactivate packet duplication for the DRB, based on the information, is transmitted to a user equipment (UE).

Methods and apparatuses are provided for activating or deactivating packet duplication in a wireless communication system. A central unit (CU) of a first base station transmits, to a distributed unit (DU) of the first base station, via an F1 interface, information to activate or deactivate a dual connectivity (DC) based packet duplication for a data radio bearer (DRB). The information is transmitted to a second base station. A medium access control (MAC) control element (CE) indicating whether to activate or deactivate packet duplication for the DRB, based on the information, is transmitted to a user equipment (UE).

User equipment (UE) includes processing circuitry coupled to memory. To configure the UE for multi-transmission reception point (TRP) reception, the processing circuitry is to decode radio resource control (RRC) signaling. The RRC signaling includes configuration information configuring a plurality of transmission configuration indication (TCI) states. A media access control (MAC) control element (CE) is decoded, where the MAC CE indicates multiple active TCI states of the configured plurality of TCI states. Multiple received beams are determined using the multiple active TCI states. Downlink information is decoded, where the downlink information originates from multiple TRPs and is received via the determined multiple receive beams associated with the multiple active TCI states.

User equipment (UE) includes processing circuitry coupled to memory. To configure the UE for multi-transmission reception point (TRP) reception, the processing circuitry is to decode radio resource control (RRC) signaling. The RRC signaling includes configuration information configuring a plurality of transmission configuration indication (TCI) states. A media access control (MAC) control element (CE) is decoded, where the MAC CE indicates multiple active TCI states of the configured plurality of TCI states. Multiple received beams are determined using the multiple active TCI states. Downlink information is decoded, where the downlink information originates from multiple TRPs and is received via the determined multiple receive beams associated with the multiple active TCI states.

A method for beam tracking and refinement in a 5G network includes determining, by a beam steering station, a first plurality of angular directions based on a first starting angular direction, a first ending angular direction and a first angular step; determining a first angular direction based on a first plurality of antenna gains associated with the first plurality of angular directions; determining a second plurality of angular directions based on a second starting angular direction, a second ending angular direction and a second angular step, wherein the first angular direction is in the middle of the second plurality of angular directions; determining a second angular direction based on a second plurality of antenna gains associated with the second plurality of angular directions; and in response to a change between the first and second angular direction being below a threshold, performing beam steering based on the second angular direction.

A method for beam tracking and refinement in a 5G network includes determining, by a beam steering station, a first plurality of angular directions based on a first starting angular direction, a first ending angular direction and a first angular step; determining a first angular direction based on a first plurality of antenna gains associated with the first plurality of angular directions; determining a second plurality of angular directions based on a second starting angular direction, a second ending angular direction and a second angular step, wherein the first angular direction is in the middle of the second plurality of angular directions; determining a second angular direction based on a second plurality of antenna gains associated with the second plurality of angular directions; and in response to a change between the first and second angular direction being below a threshold, performing beam steering based on the second angular direction.

An access method. The access method includes: acquiring an AT model type supported by each of one or more network devices; and selecting, according to the AT model type supported by each of the one or more network devices, a network device that corresponds to the AT model type matching an AT model type supported by a terminal for access.