Device-to-Device Power Control via Footroom Reporting

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Solution Overview

Problem

Current wireless communication systems face challenges in efficiently determining and managing transmission power for direct device-to-device communication, particularly in LTE systems, which can lead to interference and suboptimal performance due to inadequate power control mechanisms.

Innovation Solution

The proposed solution involves a method for efficiently transmitting and receiving synchronization signals in direct device-to-device communication by setting a minimum transmission power and using power footroom reports to dynamically adjust transmission power within set limits, ensuring optimal interference management and coverage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If transmission power is increased to improve coverage in direct device-to-device communication, then coverage area is improved, but interference to other devices increases

Engineering Contradiction:
Improvecoverage areaVSAvoidinterference
Core Design Contradiction:
Area of stationary objectVSObject-generated harmful factors

Solution Approach 1:

The patent implements dynamic transmission power adjustment where each device reports its available power range (power footroom) and the base station dynamically determines the optimal transmission power for direct device-to-device communication. This allows the system to adapt transmission power to actual communication needs rather than using fixed high power, thereby improving coverage when needed while reducing interference when not required.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the transmission power parameter dynamically based on device reports and base station determination. By adjusting the power level parameter according to the specific communication scenario and available power footroom, the system optimizes the balance between coverage and interference reduction.

Inventive Principle:
Principle #35Parameter changes

2Object-generated harmful factors

If transmission power is dynamically adjusted to reduce interference, then interference is reduced, but coverage may be compromised

Engineering Contradiction:
ImproveinterferenceVSAvoidcoverage area
Core Design Contradiction:
Object-generated harmful factorsVSArea of stationary object

Solution Approach 1:

The patent implements a feedback mechanism where devices report their available transmission power range (power footroom) to the base station. The base station uses this feedback information to determine appropriate transmission power levels for direct device-to-device communication, ensuring that power is adjusted to the minimum necessary level for successful communication while avoiding excessive interference.

Inventive Principle:
Principle #23Feedback

3Device complexity

If power control mechanisms are simplified to reduce device complexity, then device complexity is reduced, but power management precision deteriorates

Engineering Contradiction:
Improvepower control complexityVSAvoidpower management precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent enables devices to self-report their available power range (power footroom) without requiring complex centralized control. Each device autonomously determines and communicates its power capabilities to the base station, simplifying the overall control architecture while maintaining precise power management through the feedback mechanism.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3136798B1Method for determining transmit power for direct device to device communication in wireless communication system and apparatus therefor
Publication Date: 2020.09.02 LG ELECTRONICS INC
  • EP3136798B1 patent drawingFigure 1
  • EP3136798B1 patent drawingFigure 2(a)~2(b)
  • EP3136798B1 patent drawingFigure 3

AI summary

Disclosed is a method for performing, by a device, power reporting to a base station for a direct device to device communication in a wireless communication system. Specifically, the method comprises the steps of: receiving a transmit power control (TPC) command for a direct device to device communication from the base station; sending a direct device to device communication signal by determining the transmit power of a direct device to device communication according to the TPC command; and reporting the difference between the determined transmit power and a certain power to the base station.