Reference Signal Frame Positioning for DMRS Offset Tolerance
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Solution Overview
Problem
In the New Radio (NR) system, the demodulation reference signal (DMRS) and data cannot be distinguished due to large sampling clock offsets caused by low-precision ring oscillators used in IoT devices with low power consumption, leading to performance loss and incorrect demodulation.
Innovation Solution
A method is introduced where frames are structured with N reference signals and data, ensuring no other reference signal precedes the i th< and (i+1) th< reference signals, with adjusted time domain positions to account for sampling clock offsets, allowing accurate demodulation even with large frequency errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving 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 be indistinguishable
Solution Approach 1:
The patent applies preliminary action by pre-calculating and compensating for the sampling clock offset in the time domain positioning of reference signals. The transmitting device determines the time domain start position of each reference signal based on its sequence number and the maximum sampling clock offset, and the receiving device uses this pre-adjusted positioning to accurately identify reference signals before the offset causes confusion with data.
2Stability of the object's composition
If the time domain resource units for DMRS and data are made consistent in NR design, then system synchronization is improved, but reference signals and data cannot be distinguished under large sampling clock offset
Solution Approach 1:
The patent applies local quality by making the time domain positioning of reference signals different from that of data. Specifically, the time domain start position of reference signals is determined by a formula that incorporates the reference signal's sequence number and the maximum sampling clock offset, while data maintains its original positioning. This local differentiation allows reference signals to be accurately identified even when they occupy the same resource units as data.
3Reliability
If multiple reference signals are inserted in a frame to improve demodulation accuracy, then receiving performance is improved, but the complexity of identifying and positioning reference signals increases due to sampling clock offset
Solution Approach 1:
The patent applies self-service by enabling the receiving device to autonomously determine the time domain start position of each reference signal using a simple formula based on the reference signal's sequence number and the maximum sampling clock offset. This self-determination mechanism eliminates the need for complex search algorithms or additional signaling, allowing the receiver to automatically and accurately identify multiple reference signals in the frame.
Data Source
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AI summary
This application provides a reference signal sending method and receiving method and an apparatus. A terminal device generates a frame. The frame includes data and a plurality of reference signals, and 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, a performance loss caused by a sampling clock offset introduced by a low-precision ring oscillator can be reduced, and receiving performance of a receiving device can be improved.