Unlicensed Spectrum Signal Measurement Accuracy via Indication
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Solution Overview
Problem
In unlicensed spectrum systems, terminals face measurement result inaccuracies due to the inconsistency of measurement reference signals sent and received between base stations and terminals, as the base station's downlink channel occupation is unpredictable, leading to power consumption issues and inaccurate channel state measurements.
Innovation Solution
A signal transmission method where a base station sends a first indication signal to a terminal, indicating the valid time, frequency, or code domain of a measurement reference signal, allowing the terminal to measure within the channel transmission or downlink reception opportunity, thereby avoiding measurement errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the terminal measures the measurement reference signal based on the predefined position configured originally, then the terminal can perform measurement, but the measurement result will be inaccurate due to channel occupation by LBT
Solution Approach 1:
The base station performs LBT and obtains channel occupation information before the terminal performs measurement. The base station sends indication information to the terminal in advance, telling the terminal which time-domain positions have valid measurement reference signals. This preliminary action allows the terminal to adjust its measurement timing accordingly, avoiding measurement of invalid signals while maintaining measurement accuracy.
2Ease of operation
If the base station sends measurement reference signal at predefined position, then the signal transmission is simple, but the terminal cannot receive it due to unpredictable channel occupation
Solution Approach 1:
The base station performs LBT to sense the channel and obtains feedback information about channel occupation. Based on this feedback, the base station determines which time-domain positions can actually transmit measurement reference signals and sends indication information to the terminal. This feedback mechanism ensures that the base station adapts its transmission to actual channel conditions, preventing signal loss while maintaining operational simplicity.
3Reliability
If the terminal continuously monitors for measurement reference signal, then the terminal can capture the signal, but power consumption increases
Solution Approach 1:
The base station performs LBT and determines valid measurement opportunities in advance, then sends indication information to the terminal before the terminal needs to measure. This preliminary action provides the terminal with advance knowledge of when measurement reference signals will be transmitted, allowing the terminal to enter low-power states during invalid time periods and only activate its receiver during indicated valid measurement opportunities, significantly reducing power consumption while maintaining reliable signal detection.
Data Source
AI summary
Embodiments of the present application provide a signal transmission method and apparatus, a terminal and a network device. The method includes: receiving, by a terminal, a first indication signal, and determining, based on the first indication signal, at least one of a time domain, a frequency domain and a code domain of a measurement reference signal whose measurement result is valid.