Narrowband IoT Device SNR Estimation Using Unused Resource Elements
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Solution Overview
Problem
Existing narrowband IoT communication devices face challenges in accurately estimating the signal-to-noise ratio (SNR) due to insufficient noise samples obtained through narrowband reference signals.
Innovation Solution
A wireless communication device calculates the noise covariance of a target subframe using signals received through unused resource elements, allowing for more accurate SNR estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If narrowband reference signals are used to estimate noise samples for SNR calculation, then the SNR estimation can be performed, but the number of noise samples is insufficient to ensure accuracy
Solution Approach 1:
The patent applies universality by making unused resource elements serve multiple functions: they are normally left idle for resource allocation flexibility, but simultaneously utilized as noise samples for SNR estimation. This multi-functional use of unused resource elements increases the quantity of noise samples without requiring additional dedicated reference signals, thereby improving SNR estimation accuracy while maintaining system flexibility.
2Measurement precision
If unused resource elements are utilized as noise samples, then the quantity of noise samples increases improving SNR estimation accuracy, but the complexity of determining and processing these elements increases
Solution Approach 1:
The patent applies self-service by enabling the wireless communication device to autonomously identify unused resource elements based on pre-defined patterns and subframe types, and automatically process them as noise samples. The device performs self-determination of which resource elements are unused and self-processes them for SNR estimation, reducing the need for external coordination or complex centralized control while improving measurement accuracy.
3Measurement precision
If unused resource elements are used for noise sample collection, then more noise samples are available for SNR estimation, but the resource elements that could be used for data transmission are reduced
Solution Approach 1:
The patent applies discarding and recovering by taking resource elements that were discarded for data transmission (unused resource elements) and recovering their utility by utilizing them as noise samples for SNR estimation. Instead of leaving these resource elements completely idle, the system recovers their value by using them for measurement purposes, thereby improving SNR estimation accuracy without further compromising data transmission efficiency.
Data Source
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AI summary
An operating method of a wireless communication device operating in a narrowband Internet of things (IoT) communication standalone mode includes calculating a noise covariance of a target subframe based on signals received through unused resource elements in the target subframe, the target subframe being among a plurality of subframes included in a downlink signal, and the downlink signal being received from an external device, and estimating a signal-to-noise ratio (SNR) of the target subframe based on the noise covariance.