Collision Avoidance in Semi-Persistent Radio Resource Allocation

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Solution Overview

Problem

Collisions occur between dynamic and predefined resource allocations in radio access networks, such as E-UTRAN, leading to inefficiencies and potential communication failures due to high network loads and signaling errors.

Innovation Solution

A method and apparatus that determine collision risks between retransmissions and other transmissions, ignoring or acknowledging retransmission requests to avoid collisions, and prioritizing first transmissions over retransmissions in high-load conditions, utilizing enhanced Node B functionality to manage resource allocations effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If dynamic allocation and predefined allocation are both used in radio access networks, then resource allocation flexibility and service support are improved, but collision risk between transmissions increases

Engineering Contradiction:
Improveresource allocation flexibilityVSAvoidcollision risk
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies preliminary action by checking for potential collisions between dynamic and predefined allocations before finalizing resource assignments. The base station performs collision detection in advance by comparing the dynamic allocation to be granted with existing predefined allocations, and adjusts or rejects the dynamic allocation if a collision is detected, thereby preventing transmission conflicts before they occur.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If retransmission is always performed when transmission fails, then communication reliability is improved, but network load and collision probability increase

Engineering Contradiction:
Improvecommunication reliabilityVSAvoidnetwork load
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies feedback by implementing a collision detection mechanism where the base station monitors the network state and feedback from previous transmissions. When a collision is detected or predicted, the system adjusts retransmission decisions based on this feedback, selectively permitting or blocking retransmissions to avoid further collisions while maintaining necessary communication reliability.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent applies partial action by implementing selective retransmission control rather than always performing retransmission. The system performs retransmission only when it is safe to do so (when no collision is detected), and blocks retransmission when collision risk is present, thereby reducing unnecessary network load while maintaining adequate communication reliability.

Inventive Principle:
Principle #16Partial or excessive action

3Loss of information

If predefined resources are allocated for first HARQ transmissions, then signaling overhead is reduced, but collision risk with retransmission resources increases

Engineering Contradiction:
Improvesignaling overheadVSAvoidcollision risk
Core Design Contradiction:
Loss of informationVSReliability

Solution Approach 1:

The patent applies preliminary action by performing collision detection between predefined allocations and dynamic allocations before granting resources. The base station checks whether the dynamic allocation (which may be used for retransmissions) collides with predefined allocations, and takes preventive action by adjusting the dynamic allocation or blocking retransmission if a collision is detected, thereby maintaining the signaling overhead benefits while reducing collision risk.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2168385B1Avoiding collisions between semi-persistent allocation and dynamic allocation in radio access networks
Publication Date: 2018.11.14 NOKIA SOLUTIONS & NETWORKS OY
  • EP2168385B1 patent drawingFigure 1~2
  • EP2168385B1 patent drawingFigure 3~4
  • EP2168385B1 patent drawingFigure 5~6

AI summary

A method, comprising: receiving a request for retransmission from user equipment for a predetermined transmission time interval in a communication network; determining whether a collision risk exists between the retransmission and another transmission during the predetermined time interval; and ignoring the retransmission request when the determined collision risk exists.