Multi-TRP Mobility with Primary TRP Selection

The patent segments the mobility management by introducing a primary TRP concept among multiple TRPs. The UE performs RA procedure specifically with the primary TRP indicated by the gNB, while other TRPs are configured but not used for initial access. This segmentation simplifies the mobility procedure by providing a clear entry point (primary TRP) while maintaining the ability to utilize multiple TRPs for data transmission, thus resolving the contradiction between handling complex scenarios and managing procedure complexity.

The gNB performs preliminary action by indicating which TRP should be the primary TRP in the RRCReconfiguration message before the UE executes the RA procedure. This pre-designation of the primary TRP allows the UE to immediately know which TRP to target, eliminating the need to attempt RA with multiple TRPs sequentially. The reliability is maintained because the primary TRP is selected based on network knowledge of which TRP can provide reliable connection, while the time is reduced by avoiding iterative attempts with multiple TRPs.

The patent extracts the critical mobility control information from the full multi-TRP configuration by introducing a specific field (e.g., firstTRP-Index or primaryTRP-Index) that identifies only the primary TRP for RA procedure. This extraction allows the RRCReconfiguration message to include configurations for two TRPs (providing versatility) while containing a concise indicator that tells the UE exactly which TRP to use for access (reducing processing complexity). The UE doesn't need to process all TRP configurations equally, but only needs to identify and connect to the indicated primary TRP.