Random Access Method Reducing Interaction Delay in LTE Handover

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Solution Overview

Problem

The existing random access procedures in LTE systems, particularly in high-frequency bands, suffer from significant delays due to numerous interaction stages, making them unsuitable for scenarios with strict delay requirements.

Innovation Solution

The method involves a user equipment obtaining second resource information from a source cell to determine an uplink transmission dedicated resource allocated by a target cell, allowing it to access the target cell efficiently, thereby reducing the number of interaction stages and shortening the delay in the random access process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the existing random access procedure with multiple interaction stages is used, then the procedure is reliable and compatible with LTE systems, but the delay is too long for scenarios with strict delay requirements

Engineering Contradiction:
Improverandom access reliabilityVSAvoidrandom access delay
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The target cell pre-allocates uplink transmission dedicated resources and provides second resource information to the source cell before the handover. This allows the user equipment to directly use these pre-configured resources for accessing the target cell, eliminating the need for contention-based random access procedures and significantly reducing access delay while maintaining reliability through dedicated resource allocation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention extracts and removes the contention-based random access interaction stages from the handover procedure. By allocating dedicated uplink resources in advance and allowing direct access, the patent eliminates the multi-stage contention resolution process (preamble transmission, random access response, contention resolution) that causes delay, while maintaining system reliability through the dedicated resource mechanism.

Inventive Principle:
Principle #2Taking out (Extraction)

2Adaptability or versatility

If the existing contention-based random access procedure is used, then the procedure works for general LTE scenarios, but it involves too many interaction stages for high-frequency small cell deployments

Engineering Contradiction:
Improvecompatibility with LTE systemsVSAvoidnumber of interaction stages
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The target cell performs preliminary allocation of uplink transmission dedicated resources and provides second resource information to the source cell before handover execution. This pre-configuration eliminates the need for multiple interaction stages during actual access, reducing procedural complexity while maintaining LTE system compatibility through standardized message formats and interfaces.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The user equipment is enabled to autonomously access the target cell using the pre-configured uplink transmission dedicated resources and second resource information, without requiring multi-stage contention resolution interactions. This self-service approach simplifies the access procedure by eliminating dependency on complex interaction sequences between UE, source cell, and target cell.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4149199A1Random access method and equipment
Publication Date: 2023.03.15 DATANG MOBILE COMM EQUIP CO LTD
  • EP4149199A1 patent drawingFigure 1~2
  • EP4149199A1 patent drawingFigure 3~4
  • EP4149199A1 patent drawingFigure 5~6

AI summary

The present application provides methods for a random access, and a user equipment, target network-side device and source network-side device for a random access. The method includes obtaining, by a user equipment to be switched, second resource information over a source cell; determining, by the user equipment, an uplink transmission dedicated resource allocated by a target cell for the user equipment, according to the second resource information; and accessing, by the user equipment, the target cell over the uplink transmission dedicated resource.