TCI State Timer for LTM Handover Latency Reduction

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Solution Overview

Problem

Existing technologies face challenges in achieving low handover latency in wireless communication networks due to the lack of efficient mechanisms for supervising active Transmission Configuration Indicator (TCI) states during Layer1/Layer2 triggered mobility (LTM).

Innovation Solution

The proposed method involves connecting to a target cell, starting a timer associated with TCI states that were active prior to connection, and considering these states active for lower layer mobility or intra/inter cell beam management based on the timer's running status.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If TCI states are activated before providing TCI indication, then handover latency is reduced, but timer supervision mechanism is lacking

Engineering Contradiction:

Improvehandover latencyVSAvoidTCI state activation supervision

Core Design Contradiction:

Loss of timeVSReliability

Solution Approach 1:

The patent applies preliminary action by activating TCI states before the actual handover occurs. The network activates TCI states in advance during LTM preparation, allowing the UE to start tracking reference signals early and obtain fine QCL parameters before the handover is executed, thereby reducing handover latency.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback through a timer supervision mechanism. A timer is started when TCI states are activated, and the network monitors whether the UE has successfully connected to the target cell within the timer duration. If the timer expires without successful connection, the network knows the TCI state activation failed and can take appropriate actions, thus providing reliable supervision.

Inventive Principle:

Principle #23Feedback

2Adaptability or versatility

If TCI states are kept active for extended period, then beam management flexibility is improved, but resource waste increases

Engineering Contradiction:

Improvebeam management flexibilityVSAvoidresource waste

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent applies dynamics by making the TCI state activation duration time-dependent through a timer mechanism. The TCI states are kept active only for a limited time period defined by the timer, which is started when activation occurs and expires after a predetermined duration. This dynamic time-limited activation provides beam management flexibility when needed while automatically releasing resources when no longer required, preventing resource waste.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS20250071634A1Enhancement to TCI state timer operation for ltm

Publication Date: 2025.02.27 NOKIA TECHNOLOGIES OY

AI summary

A method including: connecting, with an apparatus, to a target cell; starting a timer associated with one or more transmission configuration indicator states; determining that the one or more transmission configuration indicator states were active prior to connecting to the target cell; and based upon the timer running, considering the one or more transmission configuration indicator states as being active for at least one of a lower layer mobility or for intra/inter cell beam management within the target cell.