Random Access Resource Indication Using Time Offset

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Solution Overview

Problem

In wireless communication networks, especially during handovers, user equipment (UE) faces challenges in determining the timing of random access resources for target cells, particularly when these cells are asynchronous with the serving cell, leading to inefficiencies and increased latency in the random access procedure.

Innovation Solution

The technique involves identifying a time offset from a measurement gap of the UE and the serving cell's system time, allowing the UE to perform the random access procedure without needing to decode the physical broadcast channel of the target cell, thereby reducing latency and conserving system resources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the UE decodes the physical broadcast channel of the target cell to determine timing, then the timing accuracy is improved, but the latency and energy consumption increase

Engineering Contradiction:
Improvetiming determination accuracyVSAvoidrandom access latency
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The serving base station pre-calculates and provides the time offset value to the UE before the random access procedure. This preliminary action allows the UE to determine target cell timing without decoding the physical broadcast channel, thus reducing latency while maintaining timing accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The time offset value acts as an intermediary that transfers timing information from the serving base station to the UE. Instead of the UE directly decoding the target cell's broadcast channel, it receives the timing information through this intermediary parameter, reducing the time and energy required.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of information

If the UE decodes the physical broadcast channel of the target cell, then the timing information is obtained, but the energy consumption and processing load increase

Engineering Contradiction:
Improvetiming information acquisitionVSAvoidUE energy consumption
Core Design Contradiction:
Loss of informationVSUse of energy by moving object

Solution Approach 1:

The essential timing information is extracted from the complex physical broadcast channel decoding process and provided directly as a simple time offset parameter. The UE only needs to process this extracted parameter rather than performing full broadcast channel decoding, significantly reducing energy consumption.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of the UE directly reading the target cell's broadcast channel, the serving base station copies the necessary timing information and provides it to the UE. This copying approach allows the UE to obtain timing information without the energy-intensive process of decoding the original broadcast channel.

Inventive Principle:
Principle #26Copying

3Adaptability or versatility

If the random access procedure is performed without time offset indication, then the UE can independently determine timing, but the procedure complexity and latency increase for asynchronous cells

Engineering Contradiction:
Improveindependent timing determinationVSAvoidrandom access procedure efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The invention changes the parameter provided to the UE from raw broadcast channel data to a processed time offset parameter. This parameter transformation simplifies the UE's task while maintaining the ability to handle asynchronous cells, improving procedure efficiency without sacrificing adaptability.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3682666B1Techniques and apparatuses for random access resource indication using a time offset
Publication Date: 2023.08.16 QUALCOMM INC
  • EP3682666B1 patent drawingFigure 1
  • EP3682666B1 patent drawingFigure 2
  • EP3682666B1 patent drawingFigure 3

AI summary

Certain aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment may provide information identifying a first time offset between a first time associated with a measurement performed by the user equipment and a second time associated with a measurement gap or a time value of a serving cell of the user equipment, receive information identifying a second time offset between the second time and a third time, wherein the second time offset is based at least in part on the first time offset, and/or transmit a random access message at the third time based at least in part on the second time offset. A scheduling entity may coordinate a random access procedure associated with the random access message based at least in part on the second time offset. Numerous other aspects are provided.