Multi-Symbol Reference Signals for Channel and Interference Measurement

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Solution Overview

Problem

In LTE and NR systems, accurate channel and cross-link interference measurement between wireless devices is hindered by large timing differences exceeding the cyclic prefix length, leading to inaccurate measurement results.

Innovation Solution

A new Reference Signal (RS) pattern design that occupies two or more consecutive symbols, with two cyclic prefixes (CPs) and repeated RS signals, ensuring complete signal capture within the FFT window regardless of timing alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a single cyclic prefix is used in conventional OFDM symbols, then the system maintains simple structure and timing alignment, but measurement accuracy deteriorates when timing difference exceeds CP length

Engineering Contradiction:

Improvechannel and interference measurement accuracyVSAvoidRS pattern structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The reference signal pattern is segmented into multiple consecutive OFDM symbols, each with its own cyclic prefix. This segmentation allows the total CP coverage to span multiple symbols, ensuring that the complete RS signal is captured within the extended CP window even when timing differences exceed a single CP length, thereby resolving the measurement accuracy issue without requiring excessive timing advance

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If timing alignment is maintained within CP length, then measurement accuracy is preserved, but flexibility in UL-to-DL switching and transmission timing is reduced

Engineering Contradiction:

Improvetiming flexibility for UL-to-DL switchingVSAvoidchannel and CLI measurement accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The solution extends the measurement capability from a single-symbol dimension to a multi-symbol dimension. By distributing the reference signal across multiple consecutive OFDM symbols with individual cyclic prefixes, the system gains flexibility in timing alignment while maintaining measurement accuracy. The extended temporal dimension allows UL-to-DL switching to occur within any of the multiple symbols rather than requiring precise alignment within a single symbol's CP

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Reliability

If conventional single-CP OFDM symbols are used, then transmission structure remains simple, but complete signal capture becomes impossible when timing difference exceeds CP length

Engineering Contradiction:

Improvecomplete signal capture reliabilityVSAvoidmulti-CP RS pattern configuration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The reference signal pattern is pre-configured with multiple cyclic prefixes attached to consecutive OFDM symbols before transmission. This preliminary structuring ensures that regardless of the actual timing difference encountered during transmission, the receiver will always find at least one complete RS signal within the extended CP coverage area, guaranteeing reliable signal capture without requiring real-time timing adjustments

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS20250300873A1Reference signal for channel and interference measurement

Publication Date: 2025.09.25 ZTE CORP

AI summary

Methods of transmitting and receiving reference signal (RS) patterns are disclosed, wherein the RS pattern includes occupies two or more consecutive symbols, and wherein the RS pattern comprises a first cyclic prefix (CP), at least one RS signal, and a second CP.