Network Device Tracking Reference Signal Indication for Offset Compensation
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Solution Overview
Problem
In wireless communication, especially during high-speed movements, terminal devices face challenges in compensating for time and frequency offsets caused by air interface transmission delays and Doppler effects, leading to reduced demodulation performance and communication quality due to the asynchronous timing and frequency misalignment with network devices.
Innovation Solution
A method where the network device proactively sends indication information to the terminal device to initiate measurement of a tracking reference signal before cell handover or joint transmission, allowing the terminal device to compensate for time and frequency offsets in real-time, thereby reducing the initial phase delay and improving communication quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the terminal device waits for MAC-CE signaling from the target network device before measuring the tracking reference signal, then the terminal device can ensure accurate time and frequency offset compensation, but the terminal device cannot demodulate downlink signals during the waiting period, reducing communication quality
Solution Approach 1:
The source network device performs preliminary action by sending first indication information to the terminal device before the terminal device enters the first area, instructing the terminal device to measure the tracking reference signal of the second network device in advance. This allows the terminal device to complete offset compensation before actual downlink communication begins, eliminating the waiting period problem.
2Reliability
If the terminal device performs cell handover quickly and frequently to track time and frequency offsets in real-time, then communication quality can be maintained, but the terminal device needs to wait at least for receiving MAC-CE signaling to start measuring the tracking reference signal, creating an initial phase delay
Solution Approach 1:
The source network device sends first indication information before the terminal device enters the first area, enabling the terminal device to start measuring the tracking reference signal in advance. This preliminary action eliminates the initial phase delay that would otherwise occur while waiting for MAC-CE signaling after cell handover.
Solution Approach 2:
The system establishes a feedback mechanism where the source network device monitors terminal device location and sends indication information based on whether the terminal device is about to enter the first area. This feedback loop ensures timely initiation of tracking reference signal measurement, optimizing both response time and communication quality.
3Productivity
If the terminal device directly demodulates downlink signals without measuring the tracking reference signal, then the terminal device can maintain continuous communication, but the terminal device cannot compensate for time offset and frequency offset, reducing demodulation performance
Solution Approach 1:
The terminal device performs preliminary measurement of the tracking reference signal by receiving first indication information from the source network device before entering the first area. This advance measurement allows the terminal device to have ready the necessary compensation parameters when downlink signals are received, enabling both continuous communication and accurate offset compensation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables the terminal device to directly demodulate downlink signals based on measurement results, reducing time overheads and enhancing communication quality by ensuring timely compensation for time and frequency offsets, thus improving demodulation performance.
Implementation Method 1
a downlink signal sent by the network device is affected by a Doppler effect in a transmission process. Consequently, a Doppler frequency offset (which may be referred to as a frequency offset for short) exists when the downlink signal arrives at the terminal device
Data Source
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AI summary
A communication method, apparatus, and system are provided. The method may be performed by a first network device, or may be performed by a component (for example, a processor, a chip, or a chip system) of the first network device. In the method, the first network device determines that a terminal device is to enter a first area, where the first area is an area in which the terminal device is handed over from the first network device to a second network device, or the first area is an area in which the first network device and the second network device perform joint transmission; and the first network device sends first indication information to the terminal device before the terminal device enters the first area, where the first indication information indicates to measure a first tracking reference signal of the second network device. The terminal device completes the measurement on the first tracking reference signal of the second network device before entering the first area. Therefore, after completing cell handover or during joint transmission, the terminal device may compensate for a time offset and a frequency offset in time based on a measurement result of the first tracking reference signal, so that communication quality is improved.