Discover Reference Signal Transmission in Unlicensed Spectrum

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Solution Overview

Problem

In New Radio (NR) systems, particularly in unlicensed spectrums, there is no Discover Reference Signal (DRS) available for synchronization and access, making it impossible for User Equipment (UE) to access the NR network.

Innovation Solution

A method is provided to determine and transmit the DRS in specific time and frequency domains, comprising signals like Primary Synchronization Signal (PSS), Secondary Synchronization Signal (SSS), Physical Broadcast Channel (PBCH), Demodulation Reference Signal (DMRS), and Channel State Information Reference Signal (CSI-RS) for tracking and beam management, enabling UE synchronization and channel access.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If DRS is not transmitted in unlicensed spectrum, then network access is impossible for UE, but transmitting DRS requires occupying spectrum resources which may conflict with other systems

Engineering Contradiction:

Improvenetwork access capabilityVSAvoidspectrum resource conflict

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The base station performs Listen-Before-Talk (LBT) detection before transmitting DRS to determine if the spectrum is idle. If the spectrum is available, the base station transmits DRS in advance to enable UE synchronization and network access. This preliminary action resolves the contradiction by ensuring reliable network access only when spectrum resources are available, avoiding conflicts with other systems.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If DRS transmission is performed continuously to ensure synchronization, then synchronization reliability improves, but spectrum resource occupation increases

Engineering Contradiction:

Improvesynchronization reliabilityVSAvoidspectrum resource occupation

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

Instead of continuous transmission, the base station transmits DRS periodically at predetermined intervals in unlicensed spectrum. The transmission follows a periodic pattern where the base station performs LBT detection and transmits DRS when spectrum is available, then waits for the next transmission opportunity. This periodic action maintains synchronization reliability while reducing spectrum resource occupation compared to continuous transmission.

Inventive Principle:

Principle #19Periodic action

3Adaptability or versatility

If DRS is transmitted in unlicensed spectrum, then UE can access NR network, but transmission may be interrupted by other spectrum users

Engineering Contradiction:

Improvenetwork access functionalityVSAvoidtransmission continuity

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The base station performs Listen-Before-Talk (LBT) detection before each DRS transmission to detect potential spectrum users. If another system is detected occupying the spectrum, the base station refrains from transmitting DRS, thereby preventing transmission interruptions and collisions. This preliminary anti-action ensures network access functionality while maintaining transmission stability by avoiding conflicts with other spectrum users.

Inventive Principle:

Principle #9Preliminary anti-action

Data Source

PatentUS12015571B2Reference signal transmitting and receiving method, base station, terminal, and readable medium

Publication Date: 2024.06.18 SPREADTRUM COMMUNICATION (SHANGHAI) CO LTD

AI summary

There is provided a method for transmitting a reference signal. The method for transmitting the reference signal includes: determining locations in time and frequency domains of a DRS, the DRS comprising at least one of a PSS, an SSS, a PBCH, a DMRS for PBCH, a CSI-RS for TRS, a CSI-RS for beam management, and a CSI-RS for acquiring channel state information; and transmitting the DRS at the locations in time and frequency domains of the DRS.