CSI-RS Pattern Design for LTE-NR Coexistence

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Solution Overview

Problem

In wireless communication networks, especially in 5G systems, there is a challenge in coexisting radio access technologies like LTE and NR, which operate in the same frequency ranges, leading to interference issues due to overlapping or coordinated cell transmissions, necessitating approaches that minimize signaling overhead and efficiently utilize resources.

Innovation Solution

The method involves configuring user equipment (UE) and reference radio nodes to receive and transmit channel state information reference signaling (CSI-RS) in specific patterns, with subpatterns starting at even or odd numbered subcarriers, allowing for non-overlapping distribution of CSI-RS and LTE-CRS, thereby reducing interference and optimizing resource use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If CSI-RS and LTE-CRS are transmitted in the same frequency range without pattern separation, then resource utilization is simplified, but interference between the two reference signals increases

Engineering Contradiction:

Improveresource utilizationVSAvoidinterference

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The frequency domain is segmented into even-numbered and odd-numbered subcarrier sets. CSI-RS is assigned to even-numbered subcarriers while LTE-CRS uses odd-numbered subcarriers, creating non-overlapping patterns that eliminate interference while maintaining efficient resource utilization across the entire frequency range.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If separate configuration signaling is used for each subpattern, then pattern flexibility is improved, but signaling overhead increases

Engineering Contradiction:

Improvepattern flexibilityVSAvoidsignaling overhead

Core Design Contradiction:

Adaptability or versatilityVSLoss of information

Solution Approach 1:

The configurations for even-numbered and odd-numbered subcarrier patterns are merged into a single unified configuration message. This allows the network to indicate both subpatterns simultaneously, reducing signaling overhead while maintaining the flexibility to independently control each pattern's resources and parameters.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS11616618B2CSI reference signaling in LTE/NR coexistence

Publication Date: 2023.03.28 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

There is disclosed a method of operating a user equipment in a NR radio access network, wherein the method comprises receiving channel state information reference signaling, CSI-RS, in a CSI-RS pattern. The CSI-RS pattern represents a distribution of subcarriers for carrying CSI-RS over a range of numbered subcarriers, and comprises a first subpattern and a second subpattern. The CSI-RS pattern is based on received first configuration information and received second configuration information. Further, the first configuration information indicates the first subpattern of subcarriers starting at a first starting subcarrier with even number, and the second configuration information indicates the second subpattern starting at a second starting subcarrier with an odd number. The disclosure also pertains to related methods and devices.