NR PDCCH Reception with LTE CRS Symbol Awareness

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Solution Overview

Problem

In a Dynamic Spectrum Sharing scenario, the coexistence of LTE and NR systems on the same spectrum resources causes interference, particularly due to LTE CRS puncturing NR PDCCH, leading to reduced demodulation performance and resource scheduling issues for NR PDCCH.

Innovation Solution

A method for a terminal to determine a first time-domain symbol based on CRS configuration, assessing whether to expect or receive NR PDCCH, and a network device to adjust NR PDCCH transmission accordingly, based on CRS configuration information to minimize interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If LTE and NR systems coexist on the same spectrum resources in a DSS scenario, then spectrum utilization is improved, but interference occurs between LTE CRS and NR PDCCH

Engineering Contradiction:

Improvespectrum utilizationVSAvoidinterference between LTE CRS and NR PDCCH

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful interference from LTE CRS to NR PDCCH into a beneficial mechanism by having the network device proactively identify CRS positions and notify terminals. This allows the terminal to adjust its receiving strategy, converting the potential harm of interference into a manageable situation where the terminal can optimize its reception by knowing in advance where CRS will be transmitted.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The network device performs preliminary action by determining the time-domain symbols where LTE CRS will be transmitted and notifying the terminal in advance through indication information. This preliminary notification allows the terminal to prepare its receiving strategy before the actual transmission occurs, enabling it to distinguish between CRS and PDCCH signals and optimize its demodulation performance.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If the terminal receives NR PDCCH on time-domain symbols where LTE CRS is transmitted, then resource allocation is improved, but demodulation performance deteriorates due to interference

Engineering Contradiction:

Improveresource allocationVSAvoiddemodulation performance of NR PDCCH

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent implements dynamics by enabling the terminal to flexibly adjust its PDCCH receiving strategy based on the indicated CRS time-domain symbols. Instead of a fixed receiving pattern, the terminal dynamically modifies its reception behavior by skipping or adjusting demodulation on specific symbols where CRS interference is expected, thereby maintaining reliable demodulation performance while still utilizing available resources effectively.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent applies local quality by having the terminal apply different receiving strategies to different time-domain symbols. On symbols where CRS is transmitted, the terminal uses interference-aware demodulation or skips reception, while on other symbols without CRS interference, the terminal uses standard demodulation. This localized adaptation of receiving quality optimizes overall demodulation performance by treating each symbol according to its specific interference conditions.

Inventive Principle:

Principle #3Local quality

3Productivity

If the network device transmits NR PDCCH on all available time-domain symbols, then transmission efficiency is improved, but unnecessary consumption increases due to interference on CRS symbols

Engineering Contradiction:

Improvetransmission efficiencyVSAvoidunnecessary consumption on CRS symbols

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The network device uses feedback by receiving capability information from the terminal regarding its support for PDCCH transmission on CRS symbols. Based on this feedback, the network device intelligently adjusts its transmission strategy, transmitting PDCCH on CRS symbols only when the terminal indicates it can handle the interference, thereby avoiding unnecessary transmission on symbols where the terminal cannot properly demodulate due to CRS interference.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent extracts the problematic time-domain symbols from the set of symbols used for PDCCH transmission. By identifying and separating the symbols where LTE CRS is transmitted from the overall set of available symbols, the network device can selectively exclude these extracted symbols from PDCCH transmission when appropriate, thereby eliminating unnecessary energy consumption on symbols that would result in failed demodulation at the terminal.

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentUS20250287356A1Control channel receiving method and apparatus, control channel transmitting method and apparatus, and communication apparatus and storage medium

Publication Date: 2025.09.11 BEIJING XIAOMI MOBILE SOFTWARE CO LTD

AI summary

A control channel receiving method is performed by a terminal, and includes: determining a first time-domain symbol corresponding to a cell-specific reference signal (CRS), wherein the first time-domain symbol is part or all of time-domain symbols in time-domain resources where the CRS is located; and determining, at least based on configuration information of the CRS, whether it is expected to receive a new radio physical downlink control channel (NR PDCCH) on the first time-domain symbol.