Wi-Fi Physical Frame Training Sequences for Accurate Channel Estimation
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Solution Overview
Problem
Existing wireless communication systems face challenges in accurately performing channel estimation due to the unpredictable nature of wireless channels, which affects signal demodulation, especially with higher modulation schemes, and there is a need for effective noise reduction in channel estimation.
Innovation Solution
The method involves generating a physical frame with a quantity of training sequences greater than the number of space-time streams, using a precoding matrix to increase the number of training sequences, and incorporating signaling information to indicate this quantity, thereby improving channel estimation accuracy and demodulation capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of training sequences is increased to improve channel estimation accuracy, then the demodulation capability is improved, but the frame overhead and bandwidth utilization are increased
Solution Approach 1:
The training sequences are designed to serve multiple functions simultaneously: they enable channel estimation, support demodulation of high-order modulation schemes (up to 4K QAM), and provide reference signals for signal processing. By making the training sequences multi-functional, the patent achieves improved channel estimation accuracy without requiring separate dedicated signals for each function, thereby limiting the increase in frame overhead.
Solution Approach 2:
The patent introduces signaling information that dynamically indicates the quantity of training sequences and space-time streams based on communication conditions. This parameter change approach allows the system to adapt the number of training sequences to actual channel conditions and modulation requirements, avoiding the use of excessive fixed training sequences and reducing unnecessary frame overhead while maintaining adequate channel estimation accuracy.
2Productivity
If higher modulation schemes are used to increase data rate, then the spectrum utilization is improved, but the requirement for signal-to-noise ratio and channel estimation accuracy is increased
Solution Approach 1:
The patent performs channel estimation using training sequences before demodulating the main data payload. This preliminary action of estimating the channel characteristics first allows the receiver to compensate for channel effects on high-order modulation signals, enabling reliable demodulation of 2K QAM, 4K QAM and other high-rate modulation schemes even in challenging wireless conditions.
Solution Approach 2:
The patent uses training sequences as reference copies of the transmitted signal that have not been corrupted by channel effects. These training sequence copies are embedded in the frame and allow the receiver to reconstruct the channel response by comparing the received training sequences with the known transmitted versions, thereby achieving accurate channel estimation necessary for high-order modulation demodulation.
3Reliability
If the quantity of training sequences is increased to improve demodulation capability, then the channel estimation noise reduction is improved, but the frame length and transmission time are increased
Solution Approach 1:
The patent uses a quantity of training sequences that is greater than the minimum required for basic channel estimation (excessive action), which provides noise reduction margin for high-order modulation schemes. However, the signaling information mechanism allows the system to use only the necessary number of training sequences under good channel conditions, avoiding excessive transmission time, while enabling the use of all available training sequences when channel conditions require enhanced noise reduction.
Data Source
AI summary
A Wi-Fi communication method and a device are disclosed, and relate to the field of wireless communication technologies. According to the method, a first communication device is configured to: generate a physical frame, and send the physical frame. The physical frame includes signaling information and a plurality of training sequences used for channel estimation, the signaling information indicates a quantity of space-time streams and a quantity of the plurality of training sequences, and the quantity of the plurality of training sequences is greater than the quantity of space-time streams. This helps improve accuracy of an algorithm such as channel estimation in a communication system, to improve a demodulation capability of a communication device, and ensure data demodulation effect.