Beam Indication Across CSS and USS for Inter-Cell Mobility

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Solution Overview

Problem

Existing wireless communication systems lack provisions for applying TCI states to control channels and shared channels during L1/L2 centric inter-cell mobility, particularly for CSS, leading to inefficiencies in beam management across different cells.

Innovation Solution

Implement methods for applying TCI states to both dedicated and common search spaces (CSS) associated with a CORESET, using RRC signaling, MAC CE, and DCI indications to manage beam indications for PDCCH, PDSCH, PUCCH, and PUSCH transmissions across serving and neighbor cells.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If TCI states are applied to both dedicated and common search spaces for inter-cell mobility, then beam management capability is enhanced and QoS is improved, but system complexity increases due to multiple signaling mechanisms (RRC, MAC CE, DCI)

Engineering Contradiction:

Improvebeam management capabilityVSAvoidsystem complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the beam indication process into multiple independent signaling mechanisms: RRC signaling for TCI state configuration, MAC CE for activation/deactivation, and DCI for dynamic indication. Each signaling type handles specific aspects of TCI state management, allowing the system to enhance beam management capability while distributing complexity across separate functional modules rather than concentrating it in a single complex mechanism.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If TCI states are indicated through multiple signaling mechanisms (RRC, MAC CE, DCI), then beam indication flexibility is improved, but handover latency increases due to multiple signaling steps

Engineering Contradiction:

Improvebeam indication flexibilityVSAvoidhandover latency

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by configuring TCI states in advance through RRC signaling during normal operation, so that when handover is needed, the target cell's TCI states are already available in the UE's memory. This pre-configuration eliminates the need for time-consuming TCI state setup during actual handover, reducing latency while maintaining flexibility through the multi-mechanism approach.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements dynamic beam indication through DCI formats that can quickly switch between pre-configured TCI states during handover events. The dynamic nature of DCI allows rapid activation of appropriate TCI states based on current channel conditions and handover requirements, providing both flexibility and speed in beam management during mobility transitions.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS12598035B2Systems and methods for beam indication for L1/L2 centric inter-cell mobility

Publication Date: 2026.04.07 APPLE INC

AI summary

Systems and methods for beam indication for layer 1/layer 2 (L1/L2) centric inter-cell mobility are described herein. A base station may provide a user equipment (UE) with beam indications, in one or more transmission configuration indication (TCI) states, and may provide different beam indications for different search spaces (SSs), including UE-specific search space (USS) and common search space (CSS) within a same control channel resource set (CORESET). A UE may implicitly select a radio link monitoring (RLM) and beam failure detection (BFD) reference signal (RS) in accord with one or more methods, and in some cases may implicitly select an RLM/BFD RS based on one or more received TCI states or beam indications.