Time-Domain Channel State Feedback Quantization
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Solution Overview
Problem
In multiple-user multiple-antenna communication systems, especially in OFDM systems, existing methods face challenges in efficiently transmitting channel state information from terminals to base stations due to limited feedback resources, making it difficult to accurately determine channel states across all subcarriers, which affects signal reception and interference management.
Innovation Solution
A method where terminals measure and quantify channel state information in the time domain, incorporating it into a reference signal for transmission to the base station, allowing for efficient acquisition of channel state information across the entire bandwidth while reducing the bandwidth required for transmission, and enabling improved beamforming for reduced interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If channel state information is transmitted in the frequency domain using sampled subcarriers, then feedback resources are saved, but channel state information for unsampled subcarriers cannot be accurately obtained
Solution Approach 1:
The patent inverts the conventional approach by measuring and quantizing channel state information in the time domain rather than the frequency domain. This allows the terminal to obtain accurate channel state information for all subcarriers through time-domain measurements, which are then transformed to the frequency domain for transmission, resolving the contradiction between feedback resource efficiency and measurement accuracy.
Solution Approach 2:
The patent transitions from frequency-domain channel state transmission to time-domain measurement and quantization. By measuring channel states in the time domain and then transforming to frequency domain for transmission, the system achieves both accurate channel state information acquisition and efficient feedback resource utilization.
2Quantity of substance
If quantized direction of channel vector is transmitted, then feedback overhead is reduced, but interference between selected terminals cannot be accurately evaluated
Solution Approach 1:
The patent changes the parameter representation from quantized direction of channel vector to time-domain channel state information with magnitude and phase. This allows more comprehensive channel state information to be transmitted with controlled overhead, enabling accurate evaluation of interference between selected terminals while maintaining feedback efficiency.
3Measurement precision
If channel state information is measured and quantized in time domain, then accurate channel state information for all subcarriers is obtained, but transmission bandwidth is increased
Solution Approach 1:
The patent performs preliminary quantization of time-domain channel state information at the terminal before transmission. By quantizing the channel state information in the time domain and then transforming to frequency domain for transmission, the system achieves accurate channel state information acquisition while controlling transmission bandwidth through efficient quantization.
Data Source
AI summary
The present invention relates to a channel state transmission method using time domain coefficient quantization. A terminal measures channel information in the time domain and transmits it to a base station. In this instance, a multipath frequency selective fading channel is displayed in a tapped delay line format configured with a per-path path delay value and a path gain in the time domain, differentiates a quantization level for each path gain for more efficient transmission, quantizes the same, and transmits it to a transmitter. Therefore, while the amount of bandwidths required for transmitting state information from the terminal to the base station is reduced, the base station can efficiently acquire channel state information on the entire bandwidths. Also, the base station transmits signals to many terminals through beamforming by using the acquired reliable channel state information, thereby increasing the terminal's signal receiving performance.