D2D Signal Frequency Band Adaptation for Cross-PLMN Communication

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Solution Overview

Problem

D2D communication between user terminals belonging to different Public Land Mobile Networks (PLMNs) is hindered due to mismatched frequency bands used for D2D discovery and communication procedures.

Innovation Solution

A user terminal transmits a specific D2D signal including frequency band information in a different frequency band, allowing D2D communication to commence between terminals from different PLMNs by receiving and interpreting this signal to synchronize and initiate communication in the appropriate frequency band.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If user terminals use their home PLMN's frequency band for D2D communication, then communication within the same PLMN is reliable, but D2D communication between different PLMNs cannot be established due to frequency band mismatch

Engineering Contradiction:

ImproveD2D communication reliability within same PLMNVSAvoidD2D communication compatibility between different PLMNs

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent introduces a frequency band indication signal as an intermediary carrier that conveys home PLMN frequency band information to foreign PLMN terminals. This intermediary enables terminals from different PLMNs to identify and adapt to each other's frequency bands, facilitating cross-PLMN D2D communication while maintaining the reliability of home PLMN operations

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent enables dynamic parameter changes by allowing user terminals to switch frequency bands based on the detected home PLMN frequency band information. Terminals can change their operating frequency band parameter to match the foreign terminal's home band, enabling successful cross-PLMN D2D communication while maintaining reliable communication within the home PLMN

Inventive Principle:

Principle #35Parameter changes

2Productivity

If user terminals transmit D2D signals only in their allocated frequency band, then frequency resource allocation is efficient, but foreign PLMN terminals cannot receive these signals due to frequency band mismatch

Engineering Contradiction:

ImproveFrequency resource utilization efficiencyVSAvoidD2D signal reception failure between different PLMNs

Core Design Contradiction:

ProductivityVSLoss of information

Solution Approach 1:

The patent introduces dynamic frequency band selection capability where user terminals can adaptively change their transmission frequency band based on the receiving terminal's home PLMN band. This dynamic adjustment ensures that D2D signals are transmitted on frequency bands that both terminals can access, preventing signal loss while maintaining efficient resource utilization through targeted frequency selection

Inventive Principle:

Principle #15Dynamics

3Reliability

If D2D communication is restricted to same-PLMN frequency bands, then network security and resource management are maintained, but cross-PLMN D2D communication is blocked

Engineering Contradiction:

ImproveNetwork security and resource managementVSAvoidCross-PLMN D2D communication establishment

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent implements a feedback mechanism where user terminals exchange frequency band information through indication signals before establishing D2D communication. This feedback loop allows terminals to verify frequency band compatibility and negotiate appropriate transmission parameters, enabling secure cross-PLMN communication while maintaining network resource management through controlled frequency band usage

Inventive Principle:

Principle #23Feedback

Data Source

PatentEP3110184B1User terminal and d2d communication control method

Publication Date: 2019.12.18 KYOCERA CORP

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AI summary

An UE 100#1 performs D2D communication that is direct device-to-device communication in a frequency band #1. The UE 100#1 transmits a specific D2D signal that includes frequency band information indicating the frequency band #1. The UE 100#1 transmits the specific D2D signal in frequency bands #2 and #3 different from the frequency band #1.