Random Access Resource Allocation for Handover Efficiency

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Solution Overview

Problem

In wireless communication systems, especially during cell handovers, the time difference between when a target base station configures random access resources and when a terminal device initiates access can lead to resource invalidation due to high-speed mobility, resulting in handover failures due to contention-based access conflicts.

Innovation Solution

The target network device allocates random access resources to the terminal device based on mobility state information, such as speed and direction, included in the cell handover request, to ensure non-contention-based dedicated resource allocation, reducing access failure probabilities and increasing handover success rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the target base station configures random access resources based on beam information at the handover decision moment, then the resource allocation is efficient and targeted, but the resources become invalid due to terminal mobility by the time the terminal actually accesses

Engineering Contradiction:
Improvehandover efficiencyVSAvoidaccess success rate
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by allocating multiple random access resources corresponding to different beams in advance, before the terminal actually performs random access. The target base station predicts the terminal's beam coverage area based on current beam information and mobility state, and pre-allocates resources for multiple potential beams. This ensures that when the terminal accesses, valid resources are already available even if the terminal has moved to a different beam coverage area.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements dynamics by making the random access resource allocation adaptive to the terminal's mobility state. The base station determines the terminal's mobility state (high mobility or low mobility) and adjusts the resource allocation strategy accordingly. For high mobility terminals, more beams are included in the resource allocation to cover the larger area the terminal may traverse during the access process, making the system flexible and adaptive to changing conditions.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If the terminal device uses contention-based random access resources when configured resources are invalid, then access can still be initiated, but conflicts occur and access may fail

Engineering Contradiction:
Improveaccess flexibilityVSAvoidaccess success rate
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent prevents the terminal from falling back to contention-based access by pre-allocating valid dedicated random access resources. The target base station calculates the beam coverage area based on the terminal's mobility state and pre-assigns dedicated resources for beams within this coverage area. This preliminary allocation ensures that the terminal always has valid dedicated resources to use, eliminating the need to resort to contention-based access and avoiding associated conflicts and failures.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If the target base station allocates random access resources for multiple beams in advance, then the terminal can successfully access even after moving, but resource waste increases due to over-allocation

Engineering Contradiction:
Improvehandover success rateVSAvoidresource utilization efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies local quality by differentiating resource allocation based on the terminal's specific mobility characteristics. Instead of using a uniform allocation strategy for all terminals, the base station determines each terminal's mobility state and allocates resources accordingly. For high mobility terminals, resources for more beams are allocated, while for low mobility terminals, fewer beam resources are allocated. This localized, differentiated approach optimizes resource utilization while ensuring handover success for each terminal type.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements parameter changes by dynamically adjusting the number of beams for which random access resources are allocated, based on the terminal's mobility state parameter. The base station changes the allocation parameter (number of beams) according to the terminal's mobility characteristics, rather than using a fixed allocation. This allows the system to adapt resource allocation to actual needs, reducing waste while maintaining reliability.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3611959B1Method and device for allocating random access resource
Publication Date: 2021.07.28 HUAWEI TECH CO LTD
  • EP3611959B1 patent drawingFigure 1~2
  • EP3611959B1 patent drawingFigure 3
  • EP3611959B1 patent drawingFigure 4

AI summary

A random access resource allocation method and an apparatus are provided, to increase a handover success rate of a terminal device. The random access resource allocation method includes: receiving, by a target network device, a cell handover request that is sent by a source network device and that is used to request to hand over a terminal device from the source network device to the target network device, where the cell handover request includes mobility state information of the terminal device and a measurement report of the terminal device; and allocating, by the target network device, a random access resource to the terminal device based on the mobility state information and a measurement result in the measurement report.