Pilot Signal Separation for Accurate Frequency Offset Estimation
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Solution Overview
Problem
In IoT services, especially in massive machine communications and mission-critical communications, the existing pilot transmission mode leads to inaccurate frequency offset estimation due to the limited pilot space and shared pilot usage for user detection and frequency offset estimation, resulting in poor transmission performance.
Innovation Solution
A pilot transmission method where a terminal device sends a target first pilot and a target second pilot group, with each second pilot repeated on at least two symbols, allowing the network device to perform accurate frequency offset estimation by distinguishing between user detection and frequency offset estimation pilots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single pilot is used for both user detection and frequency offset estimation, then the pilot space is reduced and resource usage is simplified, but the frequency offset estimation accuracy deteriorates
Solution Approach 1:
The patent divides the originally unified pilot into two separate pilots: a first pilot dedicated to user detection and a second pilot dedicated to frequency offset estimation. This segmentation allows each pilot to be optimized for its specific function, with the second pilot being repeatedly sent on multiple symbols to improve frequency offset estimation accuracy without increasing overall pilot space complexity.
Solution Approach 2:
The patent applies local quality by giving different functional characteristics to different pilots. The first pilot maintains properties suitable for user detection, while the second pilot is specifically designed with repetition across multiple symbols to enhance frequency offset estimation. This localized optimization resolves the contradiction by tailoring each pilot's properties to its specific purpose.
2Measurement precision
If pilots are repeatedly sent on multiple symbols for frequency offset estimation, then estimation accuracy is improved, but time-frequency resource consumption increases
Solution Approach 1:
The second pilot serves multiple functions: it is used for frequency offset estimation through repetition on multiple symbols, and simultaneously maintains orthogonality with the first pilot for user detection. This multi-functionality allows the system to achieve accurate frequency offset estimation without proportionally increasing total resource consumption, as the same pilot structure serves dual purposes.
3Device complexity
If the pilot structure is simplified for easier implementation, then device complexity is reduced, but detection reliability deteriorates
Solution Approach 1:
By segmenting the pilot structure into specialized first and second pilots with clear functional divisions, the patent actually simplifies the overall system logic and detection flow. Each pilot has a dedicated purpose, making the detection process more reliable without increasing implementation complexity, as the segmented structure eliminates the need for complex multi-purpose pilot processing.
Data Source
AI summary
This application provides a pilot transmission method, including: determining, by a first terminal device, a target first pilot and a target second pilot group corresponding to the target first pilot, where the target first pilot is used by a network device to perform terminal device detection, and the target second pilot group includes at least two second pilots; and sending, by the first terminal device, the target first pilot and the target second pilot group to the network device in a time unit, where each second pilot in the target second pilot group is repeatedly sent on at least two symbols of the time unit, and the target second pilot group is used by the network device to perform frequency offset estimation.