Wireless Handover Random Access Delay for LEO Collision Control

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Solution Overview

Problem

In non-terrestrial networks, the large cell size and satellite mobility lead to high signaling overhead, increased power consumption, and random access collisions during handovers, particularly in LEO satellite networks, due to simultaneous handovers of many UEs.

Innovation Solution

A method involving user equipment obtaining a Random Access scheduling configuration with delay and back-off values based on QoS and priority, delaying random access procedures to reduce collisions, including timer-based and back-off mechanisms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If immediate random access procedure is performed upon handover command reception, then handover speed is improved, but random access collision probability increases

Engineering Contradiction:

Improvehandover speedVSAvoidrandom access collision probability

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The base station performs preliminary actions by determining and providing UE-specific random access delay values before the actual handover execution. This allows UEs to schedule their random access procedures at different times, spreading out the access attempts and reducing collision probability while maintaining handover speed.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If many UEs perform handover simultaneously, then network resource utilization is improved, but signaling overhead increases

Engineering Contradiction:

Improvenetwork resource utilizationVSAvoidsignaling overhead

Core Design Contradiction:

ProductivityVSLoss of information

Solution Approach 1:

The random access procedure is segmented into different time slots based on UE-specific delay values. Instead of all UEs attempting random access simultaneously, they are divided into different time groups, which reduces the signaling overhead and collision probability while maintaining efficient network resource utilization.

Inventive Principle:

Principle #1Segmentation

3Reliability

If random access procedures are spread out over time, then random access collision probability is reduced, but handover delay increases

Engineering Contradiction:

Improverandom access collision probabilityVSAvoidhandover delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

Different UE-specific delay values are assigned to different UEs based on their individual characteristics and QoS requirements. This local differentiation allows the system to reduce collision probability through time spreading while minimizing the overall handover delay by optimizing each UE's delay value individually rather than applying a uniform delay to all UEs.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20250386377A1System, method, user equipment and base station for performing a handover in a wireless network

Publication Date: 2025.12.18 CONTINENTAL AUTOMOTIVE TECHNOLOGIES GMBH

AI summary

Wireless communication by a user equipment supports a handover from a first base station to a second base station. A random access scheduling configuration is obtained for at least said user equipment. The configuration includes at least a Random Access delay value. A timer, which is configured according to the Random Access Delay value, is started upon reception of a handover command from the first base station. A delayed random access procedure is triggered to the second base station when timer expires.