D2D Reference Signal Measurement for LTE Link Quality

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Solution Overview

Problem

Current wireless networks face challenges in capacity due to increased data demands from smartphones and tablets, leading to delays even when user equipment (UEs) connected to the same base station attempt to communicate, as data must traverse multiple hops through the network.

Innovation Solution

Implementing device-to-device (D2D) communication allows UEs to communicate directly without network intermediaries, using cellular spectrum while maintaining connections to the network, enabling UEs to receive signal configurations and reference signals to determine link quality and adjust transmission power for efficient communication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If device-to-device communication is implemented, then data transfer speed and system throughput are improved, but network control complexity and measurement accuracy requirements increase

Engineering Contradiction:

Improvedata transfer speedVSAvoidnetwork control complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The network entity acts as an intermediary to manage D2D communication by controlling reference signal transmission, collecting channel quality measurements, and making centralized decisions about link establishment and power adjustment, thereby reducing the complexity burden on individual UEs

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

A feedback mechanism is established where UEs measure reference signals from target UEs and report channel quality indicators to the network entity, which then adjusts transmission parameters based on this feedback to optimize D2D link performance while maintaining network control

Inventive Principle:

Principle #23Feedback

2Quantity of substance

If direct D2D communication is established between UEs, then network resource usage is reduced, but link quality measurement accuracy becomes more critical

Engineering Contradiction:

Improvenetwork resource usageVSAvoidlink quality measurement accuracy

Core Design Contradiction:

Quantity of substanceVSMeasurement precision

Solution Approach 1:

The network entity configures UEs with reference signals before D2D communication begins, allowing channel quality to be measured in advance during the configuration phase, ensuring accurate measurements are available when communication decisions need to be made

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Reference signals serve multiple functions: they enable channel quality measurement for link establishment decisions, provide basis for power adjustment, and facilitate ongoing link maintenance, thereby reducing the need for separate dedicated measurement signals

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentEP2939492B1Reference signal measurement for device-to-device communication

Publication Date: 2017.08.02 MOTOROLA MOBILITY LLC

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AI summary

A device-to-device communication is set up by an eNodeB in a LTE system based on measurements of reference signals. A first user equipment ("UE") receives information regarding a signal configuration from a network entity (eNB) on a first carrier (FDD downlink), and a reference signal from a second UE on a second carrier (FDD uplink). The second carrier is associated with a transmission bandwidth configuration and a channel bandwidth. The transmission bandwidth configuration of the second carrier is contained within the channel bandwidth of the second carrier. The reference signal is within the channel bandwidth of the second carrier and in proximity to an edge of the transmission bandwidth configuration of the second carrier.