User Equipment Pre-Decode RRC Configurations for Lower Layer Triggered Mobility

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Solution Overview

Problem

Existing communication systems face challenges in minimizing latency during lower layer triggered mobility (LTM) transitions in user equipment (UE) due to the need for real-time decoding of radio resource control (RRC) configurations upon receiving a cell switch command, leading to increased switching delays.

Innovation Solution

The UE is configured to pre-decode RRC configurations for candidate cells prior to receiving the cell switch command, allowing for early processing of transmission configuration information states, thereby reducing the latency associated with LTM transitions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If real-time decoding of RRC configurations is performed upon receiving cell switch command, then the UE can process configuration information accurately, but the switching delay increases

Engineering Contradiction:
Improveconfiguration decoding accuracyVSAvoidswitching delay
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The UE performs decoding of RRC configuration messages for candidate cells in advance, before the actual cell switch is triggered. This preliminary decoding prepares the configuration information so that when the switch command is received, the UE can immediately apply the pre-decoded configurations without real-time decoding delays, thus resolving the contradiction between decoding accuracy and switching speed

Inventive Principle:
Principle #10Preliminary action

2Loss of time

If the UE pre-decodes RRC configurations for candidate cells, then the switching latency is reduced, but the processing complexity increases

Engineering Contradiction:
Improveswitching latencyVSAvoidprocessing complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The UE is configured to perform preliminary decoding of RRC configuration messages for candidate cells during idle periods or when measurements indicate potential target cells. This advance preparation stores the decoded configuration information in memory, reducing the processing burden during actual handover events and thereby reducing switching latency without overwhelming the device complexity

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The UE applies different processing strategies to different candidate cells based on local conditions such as measurement results, cell priority, and signal quality. Only cells that meet specific criteria are pre-decoded, rather than all candidate cells uniformly. This selective approach reduces overall processing complexity while still achieving low latency for the most likely target cells

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If multiple TCI states are added to active TCI states list, then the transmission configuration flexibility is improved, but the memory and processing requirements increase

Engineering Contradiction:
Improvetransmission configuration flexibilityVSAvoidmemory and processing requirements
Core Design Contradiction:
Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The UE pre-loads and stores multiple Transmission Configuration Indicator (TCI) states in advance in its memory during the configuration phase. By having these states预先 prepared and stored, the UE can quickly switch between different transmission configurations during handover without real-time computation, thus achieving configuration flexibility while managing memory and processing requirements efficiently

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system configures the UE with a set of TCI states that may be larger than what is immediately needed, providing a pool of pre-configured options. During actual handover, only the necessary subset of TCI states is activated and applied. This approach provides adequate flexibility for various handover scenarios while avoiding the need to process and store excessively large numbers of active states simultaneously

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP4531453B1Method, apparatus and computer program
Publication Date: 2026.03.04 NOKIA TECHNOLOGIES OY
  • EP4531453B1 patent drawingFigure 1
  • EP4531453B1 patent drawingFigure 2
  • EP4531453B1 patent drawingFigure 3

AI summary

There is provided an apparatus comprising: means for receiving (600), on a source cell, a radio resource control configuration for at least one candidate cell including first configuration information and second configuration information; means for decoding (602) the first configuration information; means for performing (604) the at least one measurement based on the first configuration information; means for transmitting (606), on the source cell, a measurement report comprising at least one result of the at least one measurement; means for receiving (608), on the source cell, a message triggering the apparatus to decode the second configuration information; means for decoding (610) the second configuration information; means for receiving, on the source cell, a command to switch the apparatus to a target cell selected amongst the at least one candidate cell; and means for switching (612) to the target cell based on the second configuration information.