D2D Transmit Power Control With Minimum Coverage Guarantee

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Solution Overview

Problem

Current wireless communication systems face challenges in efficiently determining transmit power for direct device-to-device (D2D) communication, particularly in ensuring minimum coverage and managing interference between D2D and cellular communications, which affects communication quality and interference control.

Innovation Solution

A method for determining transmit power in D2D communication systems, where a UE receives a TPC command to adjust power based on minimum coverage requirements, with the option to use minimum transmit power for D2D communication when the TPC command power is lower than the minimum, and reporting power footroom to the eNB to manage interference and maintain coverage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If TPC command is used to adjust transmit power for D2D communication, then interference control is improved, but minimum coverage requirement may not be satisfied

Engineering Contradiction:
Improveinterference controlVSAvoidminimum coverage
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent implements dynamic transmit power adjustment by combining TPC commands with minimum power guarantees. The UE dynamically selects between TPC-adjusted power and minimum guaranteed power based on real-time conditions, ensuring both interference control and coverage reliability are maintained simultaneously

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the power control parameter from a single TPC command value to a range of values including both TPC-adjusted power and minimum guaranteed power. This parameter change allows the system to adapt to different operational conditions while satisfying both interference control and coverage requirements

Inventive Principle:
Principle #35Parameter changes

2Reliability

If transmit power is increased to ensure minimum coverage, then communication quality is improved, but interference with cellular signals increases

Engineering Contradiction:
Improvecommunication qualityVSAvoidinterference with cellular signals
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies partial action by using minimum guaranteed power only when necessary (when TPC commands would reduce power below coverage requirements). Otherwise, the system uses TPC-adjusted power to minimize interference. This selective application optimizes both communication quality and interference control

Inventive Principle:
Principle #16Partial or excessive action

3Adaptability or versatility

If power footroom is reported to eNB, then resource allocation flexibility is improved, but system complexity increases

Engineering Contradiction:
Improveresource allocation flexibilityVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements feedback by having the UE report power footroom information to the eNB. This feedback mechanism enables the network to make informed resource allocation decisions while the UE maintains relatively simple local processing to calculate and report the power footroom values

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3136797B1Method for determining transmission power for direct communication between terminals in wireless communication system, and apparatus for same
Publication Date: 2019.07.10 LG ELECTRONICS INC
  • EP3136797B1 patent drawingFigure 1
  • EP3136797B1 patent drawingFigure 2(a)~2(b)
  • EP3136797B1 patent drawingFigure 3

AI summary

Disclosed is a method for transmitting and receiving a signal by a device to device (D2D) terminal in a wireless communication system, according to an embodiment of the present invention, the method comprising the steps of: calculating a power headroom; and reporting the power headroom to a base station, wherein, if a terminal performs an uplink transmission to the base station on a first component carrier and performs a D2D transmission on a second component carrier, the terminal, when calculating the power headroom, considers transmission power related to a minimum coverage for D2D communication.