Time Hopping Pattern for D2D Retransmission Interference

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Solution Overview

Problem

Device-to-device (D2D) communications in wireless systems face interference and power consumption challenges due to shared wireless transmission resources, necessitating enhanced power savings and interference mitigation techniques.

Innovation Solution

Implementing a time hopping pattern for retransmissions of D2D messages, where the second transmission resource is determined based on the initial transmission resource and pattern, providing time and frequency diversity to enhance message reception and mitigate interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If D2D communications use shared wireless transmission resources, then system resource utilization is improved, but interference from base stations and other UEs increases

Engineering Contradiction:

Improvesystem resource utilizationVSAvoidinterference

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent implements periodic retransmissions of D2D messages at specific time intervals defined by a time hopping pattern. This periodic action allows the system to utilize shared wireless resources efficiently while creating predictable transmission windows that can be coordinated to minimize interference with base station and other UE transmissions.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent introduces time hopping patterns that shift transmissions across different time dimensions and frequency resources. By determining second transmission resources based on both the initial transmission resource and the time hopping pattern, the system distributes transmissions across multiple dimensions, reducing concentrated interference while maintaining resource utilization.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If D2D communications transmit messages with retransmissions, then message reception reliability is improved, but power consumption increases

Engineering Contradiction:

Improvemessage reception reliabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent employs periodic retransmissions governed by a time hopping pattern, where messages are retransmitted at specific intervals rather than continuously. This periodic approach maintains message reception reliability through multiple transmission opportunities while reducing power consumption by allowing the transmitting device to enter low-power states between scheduled retransmissions.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent changes transmission parameters dynamically by determining second transmission resources based on the initial transmission resource and time hopping pattern. This includes adjusting time offsets and frequency resources for retransmissions, optimizing the balance between reception reliability and power consumption by adapting transmission characteristics to channel conditions and interference patterns.

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If D2D communications use time hopping patterns for retransmissions, then interference mitigation is improved, but transmission resource determination complexity increases

Engineering Contradiction:

Improveinterference mitigationVSAvoidtransmission resource determination complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent uses time hopping patterns that introduce time and frequency diversity by shifting transmissions to different resources. The second transmission resource is determined based on the initial transmission resource plus a time hopping offset, spreading transmissions across multiple dimensions to mitigate interference while using systematic methods to manage resource determination.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The transmitting device autonomously determines its own retransmission resources by applying the time hopping pattern to the initial transmission resource. This self-service approach allows the device to independently manage interference mitigation without requiring complex centralized coordination, reducing overall system complexity while maintaining effective interference avoidance.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS10477538B2Time hopping in device-to-device transmissions

Publication Date: 2019.11.12 QUALCOMM INC

AI summary

Apparatuses, systems, and devices are described for transmissions and retransmissions of device-to-device (D2D) communications. A D2D message may be transmitted during an initial communications period, followed by one or more retransmissions. A device may transmit an initial transmission, determine a time hopping pattern for the retransmission(s), and determine a transmission resource for the retransmission(s) based at least in part on a resource of the initial transmission and the time hopping pattern. The messages may include, for example, a scheduling assignment (SA) for data transmission, or data transmissions from a transmitting device. Time hopping patterns may be determined based on times and/or frequencies of the initial transmission. A base station may transmit a message to a transmitting device that indicates one or more time hopping patterns that are to be used for the transmissions.