Channel State Information via Guided Uplink and Downlink Reference Signals
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Solution Overview
Problem
Existing 5G communication systems face inefficiencies in determining channel state information due to the wastage of time-frequency resources and high computational complexity in pilot-based measurement methods, particularly in TDD and FDD systems.
Innovation Solution
A method involving a network device indicating positions for sending downlink and uplink reference signals to a terminal device, allowing the terminal to determine channel statistics without occupying excessive resources and reducing computational complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a terminal device directly measures channel state information by using a pilot, then channel state information can be obtained, but a large quantity of time-frequency resources are consumed
Solution Approach 1:
The patent segments the channel measurement process into two parts: the terminal device measures downlink channel statistics using a downlink pilot, and the network device measures uplink channel statistics using an uplink pilot. This segmentation allows both devices to contribute to channel state information acquisition, reducing the overall resource consumption compared to the terminal device performing all measurements alone.
Solution Approach 2:
The patent inverts the traditional measurement approach by having the terminal device send an uplink pilot for the network device to measure, rather than only the terminal device measuring downlink channels. This inversion leverages uplink-downlink channel reciprocity in TDD systems, allowing the network device to obtain downlink channel information through uplink measurements, thereby reducing the time-frequency resources required at the terminal device.
2Measurement precision
If a terminal device calculates channel state information based on a downlink pilot, then channel state information can be obtained, but high calculation complexity is imposed on the terminal device
Solution Approach 1:
The patent extracts the complex channel state information calculation task from the terminal device and transfers it to the network device. The terminal device only performs simple downlink channel statistics measurement and sends the results to the network device, which then performs the computationally intensive uplink channel statistics measurement and channel state information calculation. This extraction significantly reduces the calculation complexity burden on the terminal device.
Solution Approach 2:
The patent introduces channel statistics information as an intermediary between the pilot signal and the final channel state information. Instead of the terminal device directly calculating channel state information from pilots, it first measures and sends channel statistics to the network device, which then uses these statistics along with uplink pilot measurements to determine the final channel state information. This intermediary approach simplifies the terminal device's computational tasks.
Data Source
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AI summary
This application provides a method for determining channel state information and a communication apparatus. The method provided in this application includes: sending first indication information, where the first indication information indicates a position for sending a downlink reference signal; receiving channel statistics information, where the channel statistics information is determined based on the downlink reference signal; sending second indication information, where the second indication information indicates a position for sending an uplink reference signal; and receiving the uplink reference signal, and determining channel state information based on the uplink reference signal and the channel statistics information. According to the method provided in this application, a terminal device sends the uplink reference signal based on an indication of a network device, and therefore a large quantity of time-frequency resources do not need to be occupied. In addition, the network device calculates the channel state information based on the uplink reference signal and the channel statistics information, and therefore, the terminal device is not required to have high calculation complexity.