Reference Signal Frame Layout for Sampling Clock Offset Tolerance
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Solution Overview
Problem
In NR systems, large sampling clock offsets due to low-precision ring oscillators in IoT devices with low power consumption and low costs lead to indistinguishability between DMRS and data, causing performance loss and incorrect demodulation, which is not addressed by existing NR protocols.
Innovation Solution
A method is introduced where frames are structured with N reference signals and data, ensuring no other reference signal precedes an ith and (i+1)th signal, with data between them, and adjusting symbol time lengths and start positions to accommodate maximum allowed sampling clock offsets, enabling accurate demodulation even with large frequency errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If a low-precision ring oscillator is used in IoT terminals to reduce power consumption and cost, then power consumption and cost are reduced, but sampling clock offset increases causing reference signals and data to become indistinguishable
Solution Approach 1:
The frame is segmented into multiple reference signals separated by data, rather than a single continuous reference signal. This segmentation allows the receiver to identify reference signals even when sampling clock offset causes timing drift, as each reference signal can be independently detected and correlated
Solution Approach 2:
Multiple reference signals are distributed throughout the frame at continuous intervals, ensuring that at least one reference signal remains identifiable despite sampling clock offset. This continuous distribution of reference signals maintains demodulation capability throughout the entire frame duration
2Adaptability or versatility
If the sampling clock offset is increased beyond ±0.1 ppm in NR protocol, then IoT terminals with low-precision oscillators can be used, but the DMRS and data cannot be distinguished leading to incorrect demodulation
Solution Approach 1:
The frame structure is designed in advance with multiple reference signals positioned at specific intervals, preparing the signal structure to withstand sampling clock offset before transmission occurs. This preliminary design ensures that even with large frequency errors, the reference signals remain detectable
Solution Approach 2:
The invention converts the harmful effect of large sampling clock offset into a beneficial feature by designing a frame structure where multiple reference signals are spaced such that the offset actually helps distinguish reference signals from data through pattern recognition, rather than causing confusion
Data Source
AI summary
A reference signal sending method and receiving method and a related apparatus are disclosed. A terminal device generates a frame including data and a plurality of reference signals. The frame is arranged such that a difference between start positions of two adjacent reference signals is associated with a maximum sampling clock offset allowed by the terminal device. According to the method, the performance loss caused by a sampling clock offset introduced by the low-precision ring oscillator can be reduced, and receiving performance of a receiving device can be improved.