Some aspects relate to apparatuses and methods for implementing mechanisms for performing handover, radio link monitoring (RLM), beam failure detection (BFD), and candidate beam detection (CBD) within the unlicensed spectrum when a listen-before-talk (LBT) failure occurs and/or when a user equipment (UE) performs receiving (RX) beam sweeping. For example, a UE is configured to receive a handover command to connect to a target cell. The UE is further configured to determine a search time and an interruption time uncertainty during a handover procedure initiated by the handover command and in response to a LBT failure or the UE performing a beam sweeping operation. The UE can further determine a handover delay based on the search time and the interruption time uncertainty. In response to a time period for performing the handover procedure exceeding the handover delay, the UE can cease the handover procedure.

A first configuration of a first set of random access channel occasions can be transmitted in a handover command message from a first cell. A second configuration of a second set of random access channel occasions of a second cell can be transmitted. The second set of random access channel occasions can be different from the first set of random access channel occasions. System information of the second cell can include the second configuration of the second set of random access channel occasions. A random access channel preamble can be received on a random access channel occasion. At least one selected from the first set of random access channel occasions and the second set of random access channel occasions can include the random access channel occasion. The first cell can be different from the second cell.

Systems, apparatuses, and methods are described for wireless communications. Random access procedures may include various types of procedures, such as 4-step or 2-step random access procedures. One or more indicators may be included in one or more messages for a handover to indicate a type of a random access procedure.

Example aspects include a method, apparatus, and computer-readable medium for network-triggered reestablishment by a network node of a wireless communication network, comprising transmitting, to a user equipment (UE) in a connected state with a first central unit (CU), an indication to perform a radio resource control (RRC) reestablishment procedure with a second CU. The indication comprises a reestablishment cell identifier. The aspects further include performing the RRC reestablishment procedure with the UE to transfer the UE from the first CU to the second CU using the reestablishment cell identifier.

An information transmission method including: performing a compliance check on a cell configuration of a target cell included in a conditional handover command; when the compliance check on the cell configuration fails, at least recording a cell identifier of the target cell; and reporting failure record information including the cell identifier.

A random access method including receiving, by a user equipment, a radio resource control (RRC) connection reconfiguration message from a first network device, where the RRC connection reconfiguration message is included in a first message sent by a second network device to the first network device, and where the RRC connection reconfiguration message indicates a primary serving cell of the second network device for the user equipment, and further indicates an active bandwidth part (BWP) in the primary serving cell, and the method further including initiating, by the user equipment, a random access procedure on the active BWP.

The present disclosure relates to a communication method and system for converging a 5.sup.th-Generation (5G) communication system for supporting higher data rates beyond a 4.sup.th-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. According to the disclosure, a base station may configure serving cells having different frame start time points, using carrier aggregation (CA), for operation of a terminal, and thus can increase the transmission rate of the terminal.

Methods (1500, 1600, 1700, 1800, 1900), systems (1000, 1400) and devices (705, 805, 1005, 1105, 1205, 1405) for wireless communications are presented. A method (1500, 1600) may include the following operations. A UE determines to perform a handover from a first source device in a first network to a first target device in the first network and from a second source device in a second network to a second target device in the second network (1505, 1605). The UE identifies a time interval for performing a first random access procedure with the first target device in the first network (1510, 1610). The UE initiates a first random access procedure with the first target device (1515, 1615). The UE performs a second random access procedure successfully with the second target device in the second network during the time interval (1520, 1620). The UE transmits or receives from the target device in the second network before the UE finishes performing the first random access procedure with the first target device in the first network (1525, 1630).

The present invention relates to a method for random access to a small cell by means of a terminal. The method can include the steps of: receiving a plurality of settings for a random access preamble; selecting one of the plurality of settings; and transmitting the random access preamble according to the one selected setting. Here, a resource on which the random access preamble can be transmitted can be provided in plurality in one subframe, and the preamble transmitted on each resource is distinguishable.

A method of UE includes receiving a radio resource control (RRC) message for configuring bandwidth parts (BWPs) of a serving cell, receiving a physical downlink control channel (PDCCH) indicating activation of a first BWP, performing a BWP switching to the first BWP indicated by the PDCCH, and starting a first downlink BWP timer associated with the first BWP. A UE includes a transceiver, and at least one controller coupled with the transceiver, the at least one controller configured to receive an RRC message for configuring BWPs of a serving cell, receive a PDCCH indicating activation of a first BWP, perform a BWP switching to the first BWP indicated by the PDCCH, and start a first downlink BWP timer associated with the first BWP.