Communication method and communications apparatus
摘要
說明書
Specifically, the first network device uses, based on measurement information of the neighboring cell included in the measurement report, the neighboring cell included in the measurement report as a candidate target cell, and determines the candidate target network device based on the candidate target cell. The candidate target network device is a network device to which the candidate target cell belongs. The candidate target network device includes one or more network devices. In this embodiment of this application, the candidate target network device may also be referred to as a fourth network device. It should be understood that a second network device in this specification is one of the one or more network devices included by the candidate target network device. In other words, the second network device may be a network device to which a first target cell belongs, and the second network device is a network device in the candidate target network device. Optionally, the second network device may also be referred to as a candidate target network device. The first network device sends a message to the candidate target network device, to request the candidate target network device to perform handover preparation. The message may be a handover request message or another message, or may have another name. This is not limited in this application. The message includes context information of the terminal device. For example, the context information includes radio access capability information, a security parameter, a radio bearer configuration, an RRM configuration, and the like of the terminal device. After receiving the request message, the candidate target network device performs admission control. If it is determined that the terminal device is allowed to access the candidate target network device, the candidate target network device returns a message to a source network device (that is, the first network device). The message may be a handover request acknowledgment message or another message. This is not limited. The message returned by the candidate target network device includes configuration information required by the terminal device to access the candidate target network device. For example, the handover request acknowledgment message may include information that is required for accessing the candidate target cell and that is configured by the candidate target network device for the terminal device. The candidate target cell belongs to the candidate target network device. For example, the handover request acknowledgment message includes a cell identifier of the candidate target cell, frequency information of the candidate target cell, a C-RNTI allocated by the candidate target cell to the terminal device, an identifier of a first beam that belongs to the candidate target cell, and a first random access channel RACH resource. Specifically, the cell identifier includes a PCI and/or a CGI. The frequency information includes an SSB frequency (for example, absoluteFrequencySSB) of the candidate target cell and/or an absolute frequency position (for example, absoluteFrequencyPointA) of a reference resource block (common RBo) of the candidate target cell. The identifier of the first beam includes an SSB index and/or a CSI-RS index. The first random access channel RACH resource includes a first dedicated random access resource and/or a first common random access resource. The first dedicated random access resource is associated with the first beam, the first dedicated random access resource includes a first preamble index and a first time-frequency resource, and the first common random access resource includes a second time-frequency resource.
