D2D Discovery Load Control via UE Classification and Feedback

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Solution Overview

Problem

Current load control systems for device-to-device (D2D) discovery signal transmissions in communication systems, particularly in broadcast environments, face challenges in maintaining optimal throughput and fairness due to the lack of centralized control and inability to adapt to local variations in UE density and activity, leading to resource underutilization or overload.

Innovation Solution

A distributed load control system where user equipment (UEs) adjust their transmission probabilities based on observed load and mean transmission probabilities, classifying UEs into types (A, B, C) with different target probabilities, allowing for flexible resource usage and reporting to maintain optimal load and fairness, with rules for tuning and broadcasting TX probability values.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a contention based approach is used for D2D discovery signal transmissions, then idle mode UEs can be supported, but there is no way for transmitting devices to know whether their discovery signal has collided with another device's signal, making load control ineffective

Engineering Contradiction:
Improvesupport for idle mode UEsVSAvoidload control effectiveness
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces a feedback mechanism where UEs report collision information to the network element. The network element receives feedback about discovery signal collisions from multiple UEs and uses this information to adjust transmission probabilities, enabling effective load control in contention-based D2D discovery systems.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The network element acts as an intermediary that collects collision feedback from UEs and computes adjusted transmission probabilities. This intermediary coordinates the random access process by providing UEs with updated transmission probabilities based on observed collision patterns, resolving the inability of UEs to self-regulate in pure contention-based systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If transmission probability is increased to support more UEs, then system capacity increases, but resource overload and collision increase occur

Engineering Contradiction:
Improvesystem capacityVSAvoidresource overload and collision
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent implements dynamic adjustment of transmission probabilities based on observed system conditions. The network element monitors collision feedback and continuously updates transmission probabilities for different UEs, allowing the system to adapt to changing load conditions and maintain optimal performance without static probability assignments.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the transmission probability parameter dynamically based on observed collision rates and system load. By adjusting this key parameter according to feedback information, the system can increase capacity when conditions permit while preventing overload when collisions indicate excessive load.

Inventive Principle:
Principle #35Parameter changes

3Object-generated harmful factors

If transmission probability is decreased to reduce collisions, then resource overload is prevented, but throughput and system capacity decrease

Engineering Contradiction:
Improvecollision reductionVSAvoidthroughput
Core Design Contradiction:
Object-generated harmful factorsVSProductivity

Solution Approach 1:

The patent applies different transmission probabilities to different UEs based on their local conditions and observed collision patterns. Instead of a uniform probability reduction, the network element provides UE-specific probability adjustments, allowing some UEs to maintain higher transmission rates while others reduce their rates to minimize collisions, thereby preserving overall throughput.

Inventive Principle:
Principle #3Local quality

4Productivity

If centralized control is implemented to optimize resource allocation, then throughput and fairness are improved, but system complexity and control overhead increase

Engineering Contradiction:
Improvethroughput and fairnessVSAvoidcontrol system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The network element serves as a lightweight intermediary that collects simple feedback from UEs and provides adjusted transmission probability recommendations. This intermediary approach enables centralized optimization without requiring complex control mechanisms, as the network element only needs to process feedback reports and compute probability adjustments based on observed collision patterns.

Inventive Principle:
Principle #24Intermediary (Mediator)

5Device complexity

If distributed control is used to reduce complexity, then system simplicity is maintained, but ability to adapt to local variations in UE density and activity is reduced

Engineering Contradiction:
Improvecontrol system simplicityVSAvoidadaptation to local variations
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent implements a feedback-based distributed control mechanism where UEs report local collision conditions to the network element. This feedback enables UEs to adapt their transmission behavior based on local density and activity variations, while the network element coordinates adjustments across the system, combining distributed simplicity with centralized adaptability.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3100504B1Load control system for device to device discovery signal transmissions
Publication Date: 2021.07.28 NOKIA TECHNOLOGIES OY
  • EP3100504B1 patent drawingFigure 1A
  • EP3100504B1 patent drawingFigure 1B
  • EP3100504B1 patent drawingFigure 1C

AI summary

Various communication systems may benefit from load control. For example, systems that employ device-to-device discovery signal transmissions may benefit from such load control. A method can include determining a first classification of a user equipment according to desired or allowed transmission probability. The method can also include configuring a transmission probability based on the first classification. The method can further include operating the user equipment based on the transmission probability.