Pilot Signal Separation for Accurate Frequency Offset Estimation
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Solution Overview
Problem
The existing pilot transmission methods in IoT services, particularly in massive machine communications and mission critical communications, face challenges with inaccurate frequency offset estimation due to limited pilot space, high detection complexity, and poor reliability, leading to suboptimal transmission performance.
Innovation Solution
The proposed solution involves a pilot transmission method where a terminal device sends a target first pilot and a corresponding target second pilot group, with each second pilot repeated on at least two symbols, to enable accurate frequency offset estimation and improve system performance, using non-orthogonal and orthogonal pilot sets to distinguish between user detection and frequency offset estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the same pilot is used for both user detection and frequency offset estimation, then the pilot space is reduced and detection complexity is lowered, but the frequency offset estimation accuracy deteriorates
Solution Approach 1:
The patent divides the pilot function 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 at least two symbols to improve frequency offset estimation accuracy without interfering with user detection operations.
2Quantity of substance
If a single pilot is used for multiple functions, then the overall system resource usage is reduced, but the reliability of each individual function deteriorates
Solution Approach 1:
The patent segments the pilot resources into two distinct pilots with dedicated functions. The first pilot handles user detection while the second pilot handles frequency offset estimation, with the second pilot being transmitted repeatedly across at least two symbols. This segmentation improves the reliability of frequency offset estimation by providing multiple measurement opportunities while maintaining efficient resource usage through the specialized division of labor between the two pilots.
3Device complexity
If the pilot space is limited, then the system complexity is reduced, but the frequency offset estimation accuracy and transmission performance deteriorate
Solution Approach 1:
The patent segments the pilot functionality to resolve the contradiction between limited pilot space and estimation accuracy. By separating user detection and frequency offset estimation into different pilots, the system maintains a manageable pilot space structure while the second pilot's repeated transmission on at least two symbols provides sufficient data for accurate frequency offset estimation without expanding overall system complexity.
Data Source
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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. According to the pilot transmission method provided in embodiments of this application, two pilots are distinguished. A first pilot is used for terminal device detection, a second pilot group corresponding to the first pilot is used for frequency offset estimation, and each second pilot in the second pilot group is repeated on at least two symbols of a time unit. This can support accurate frequency offset estimation, thereby improving system performance.