Extended SRS Symbol Length for Satellite Uplink Timing Tracking
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Solution Overview
Problem
Satellite mobile communication systems face challenges in tracking uplink timing and frequency offsets due to high change rates, which existing SRS structures specified in protocols are unable to effectively handle, leading to limitations in uplink timing location detection and synchronization.
Innovation Solution
The proposed solution involves generating and processing a channel sounding reference signal (SRS) with an extended symbol length and detectable change range, achieved by performing time domain mapping on a masked SRS frequency domain sequence. This allows the terminal device to send an SRS that can be detected by the base station to track uplink timing and frequency offsets effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing SRS structures specified in protocols are used, then the system maintains compatibility with standard protocols, but the detectable change range of uplink timing location is insufficient for satellite communication scenarios
Solution Approach 1:
The patent changes the parameter of SRS symbol length from the standard configuration to an extended length. Specifically, the SRS symbol length is extended to cover at least one complete uplink slot, which significantly increases the detectable change range of uplink timing location. This parameter change allows the system to maintain protocol compatibility while adapting to the high mobility characteristics of satellite communication.
Solution Approach 2:
The patent introduces dynamic adjustment mechanisms for SRS transmission parameters including variable symbol lengths, flexible time-frequency resource allocation, and adaptive cyclic shift values. These dynamic parameters allow the system to adapt to different satellite communication scenarios and mobility conditions, expanding the detectable timing location change range while maintaining reliability.
2Measurement precision
If the SRS symbol length is extended to increase detectable change range, then the tracking capability improves, but the time consumption for timing estimation increases
Solution Approach 1:
The patent extracts and emphasizes the correlation estimation process as a separate, optimized function. By focusing on correlating the received SRS signal with locally generated reference signals of extended length, the system achieves accurate timing location detection without requiring complete processing of the entire extended symbol, thereby reducing the effective processing time.
Solution Approach 2:
The patent performs preliminary preparation of reference signals and correlation templates before actual SRS reception. The base station pre-generates reference signals with extended symbol lengths and prepares correlation detection templates, so that when SRS signals are received, the timing estimation can be performed more quickly through pre-computed correlation operations.
3Reliability
If closed-loop measurement method is used for terminals without GNSS positioning capability, then the terminal can track uplink timing and frequency offset, but the system complexity increases due to additional signaling and feedback requirements
Solution Approach 1:
The patent makes the SRS signal serve multiple functions simultaneously: it acts as both a channel quality estimation signal and a timing/frequency offset tracking signal. By extending the SRS symbol length and enabling base station measurement of timing location changes directly from SRS signals, the system eliminates the need for separate timing reference signals, thereby reducing overall system complexity while maintaining synchronization capability.
Solution Approach 2:
The patent merges the timing tracking function with the existing SRS transmission mechanism. Instead of implementing a separate closed-loop measurement system with dedicated timing reference signals and feedback channels, the patent combines timing estimation functionality into the regular SRS signaling framework, reducing the number of separate components and simplifying the overall measurement and feedback mechanism.
Data Source
AI summary
This application discloses example signal sending methods and apparatuses, and example signal processing methods and apparatuses. One example method includes generating, by a terminal device, a channel sounding reference signal (SRS). The terminal device can then send the SRS to a target base station, where the target base station detects, by using the SRS, that a change range of an uplink timing location of the terminal device is not less than a length of one SRS symbol.