D2D Synchronization Signal Hop Number Determination

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Solution Overview

Problem

In device-to-device (D2D) synchronization in wireless networks, it is challenging to identify the associated hop number of synchronization signals, leading to interference and dependency on a single failure point in multihop synchronization scenarios.

Innovation Solution

A method and apparatus for determining the hop number of D2D synchronization signals based on radio resources, deciding whether to transmit these signals to a second network node, thereby mitigating interference and limiting dependency on a single point by mapping D2DSS/PD2DSCH resources to different hop numbers in an orthogonal fashion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If D2D synchronization signals are transmitted without hop number identification, then the transmission process is simple, but interference occurs and reliability deteriorates

Engineering Contradiction:

Improvetransmission process complexityVSAvoidsynchronization signal reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent segments the radio resources into different sets corresponding to different hop numbers. By dividing the resource space into distinct segments (first set of resources for first hop number, second set for second hop number, etc.), the system enables reliable identification and transmission of synchronization signals from multiple synchronization heads without interference, resolving the contradiction between simplicity and reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by assigning different characteristics to different resource sets based on their associated hop numbers. Each resource set has unique identification characteristics that correspond to its hop number, allowing receivers to distinguish between signals from different synchronization heads. This localized differentiation improves reliability while maintaining manageable complexity through structured resource allocation.

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If all D2D synchronization signals are transmitted to all network nodes, then coverage is maximized, but interference and error propagation increase

Engineering Contradiction:

Improvesignal coverageVSAvoidinterference and error propagation

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the transmission process by hop number, where each synchronization head transmits signals only to network nodes within its specific hop range. The first synchronization head transmits to first network nodes (first hop), and the second synchronization head transmits to second network nodes (second hop). This segmentation limits interference and error propagation to local areas while maintaining comprehensive coverage through multiple synchronized transmissions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces hop number as an intermediary parameter that mediates between transmission sources and receivers. By using hop number as an intermediate identifier, the system enables selective transmission and reception, allowing nodes to forward synchronization signals only to appropriate destinations within their hop range. This intermediary mechanism prevents unnecessary interference while preserving coverage across the entire network.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If D2DSS/PD2DSCH resources are not mapped to different hop numbers orthogonally, then resource allocation is simple, but interference occurs between different hop numbers

Engineering Contradiction:

Improveresource allocation simplicityVSAvoidinterference between hops

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent segments the resource allocation process by creating distinct resource sets for different hop numbers. The first set of D2DSS/PD2DSCH resources is allocated for the first hop number, and the second set is allocated for the second hop number. This segmentation enables orthogonal mapping that prevents interference between hops while maintaining systematic and manageable resource allocation through predefined mapping rules.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces hop number as an additional dimension for resource mapping. By mapping resources not only in the traditional time-frequency domain but also adding the hop number dimension, the system creates orthogonal resource sets that are distinguished by multiple dimensions. This dimensional expansion prevents interference between different hops while maintaining allocation simplicity through structured, rule-based mapping across the extended resource space.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS10616841B2Method and apparatus for transmitting D2D synchronization signals

Publication Date: 2020.04.07 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

Embodiments of the disclosure provide a method, an apparatus, a network node, and a computer program product for transmitting D2D synchronization signals. According to the method, D2D synchronization signals are received from a first network node. A hop number of the D2D synchronization signals is determined based on radio resources of the D2D synchronization signals. Whether to transmit the D2D synchronization signals to a second network node is determined based on the hop number.