Terminal Timing Control for D2D Cellular Interference

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Solution Overview

Problem

In LTE systems, D2D communication within cellular coverage experiences interference with cellular communication, and simultaneous D2D and cellular communication performance has not been adequately studied.

Innovation Solution

A terminal apparatus that synchronizes with a base station using a Timing Advance (TA) command to transmit signals, allowing for efficient D2D communication by coordinating transmission timing with cellular communication, including starting a TA timer and adjusting transmission based on TA command expiration and cell group affiliations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If D2D communication is performed within LTE coverage, then D2D communication capability is enabled, but interference occurs between D2D and cellular communication

Engineering Contradiction:

ImproveD2D communication capabilityVSAvoidinterference with cellular communication

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the transmission timing control into two distinct mechanisms: TA-based timing for cellular communication and synchronized timing for D2D communication. By dividing the timing control into separate domains, the system enables D2D communication capability while preventing interference with cellular communication through independent timing management.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies preliminary action by having the terminal apparatus synchronize its D2D transmission timing with the downlink frame timing of the EUTRAN before actual D2D communication occurs. This advance synchronization ensures that D2D transmissions are pre-coordinated with cellular communication schedules, preventing interference while enabling D2D capability.

Inventive Principle:

Principle #10Preliminary action

2Adaptability or versatility

If terminal apparatus transmits both cellular uplink signals and D2D signals, then communication functionality is enhanced, but transmission timing coordination becomes complex

Engineering Contradiction:

Improvecommunication functionalityVSAvoidtransmission timing coordination

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the timing reference for D2D communication with the cellular downlink frame timing. By combining the timing synchronization mechanism of D2D with the existing cellular downlink timing structure, the system enhances communication functionality while reducing timing coordination complexity through unified timing reference.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent implements feedback by using the downlink frame timing from the base station as a reference for D2D transmission timing. This feedback mechanism allows the terminal apparatus to continuously adjust its D2D transmission timing based on the received downlink timing, simplifying coordination while maintaining enhanced communication functionality.

Inventive Principle:

Principle #23Feedback

3Reliability

If TA command is used for uplink timing adjustment, then cellular communication quality is improved, but D2D transmission timing control becomes restricted

Engineering Contradiction:

Improvecellular communication qualityVSAvoidD2D transmission timing control

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent extracts the timing synchronization function for D2D communication from the TA command mechanism. By separating D2D timing control from cellular TA commands, the system maintains reliable cellular communication through TA while enabling flexible D2D transmission timing control through downlink frame timing synchronization.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent inverts the traditional timing control approach by using downlink timing (received from base station) to control uplink D2D transmission timing, rather than using uplink TA commands. This inversion allows D2D timing control independence while preserving cellular communication quality through continued TA usage for cellular uplink.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS10015763B2Terminal apparatus and base station apparatus

Publication Date: 2018.07.03 SHARP KK

AI summary

A terminal apparatus detects a downlink frame timing based on a synchronization signal in EUTRAN, receives a TA (Timing Advance) command from a base station apparatus of the EUTRAN, transmits an uplink signal in the EUTRAN to the base station apparatus of the EUTRAN at a timing based on at least the downlink frame timing and a value of the TA command, and transmits a signal between terminal apparatuses to another terminal apparatus at the same timing.