PPDU Pilot Subcarrier Power Allocation for Accurate Demodulation
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Solution Overview
Problem
The demodulation accuracy of wireless communication systems using millimeter-wave frequency bands is compromised due to insufficient pilot energy, leading to high packet error rates and reduced signal-to-noise ratios.
Innovation Solution
Increase the signal modulus value of the pilot subcarrier relative to the data subcarrier in a PPDU to enhance pilot energy, enabling effective phase and frequency offset corrections, thereby improving demodulation accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the signal modulus value of the pilot subcarrier is increased to enhance pilot energy, then demodulation accuracy is improved, but the total transmit power increases
Solution Approach 1:
The patent applies local quality by differentiating the signal modulus values between pilot subcarriers and data subcarriers. Specifically, pilot subcarriers are assigned a first signal modulus value while data subcarriers are assigned a second signal modulus value, creating localized quality enhancement where it is most needed (in pilot signals for phase tracking) without uniformly increasing all signal power
Solution Approach 2:
The patent changes the parameter of signal modulus value specifically for pilot subcarriers. By setting the first signal modulus value for pilot subcarriers and the second signal modulus value for data subcarriers, the patent modifies the physical parameter of signal strength locally, thereby improving pilot energy and demodulation accuracy without proportionally increasing total transmit power
2Measurement precision
If the signal modulus value of the pilot subcarrier is increased to improve phase tracking accuracy, then frequency offset correction accuracy is improved, but the packet error rate increases due to total power constraints
Solution Approach 1:
The patent enhances the quality of pilot subcarriers specifically by assigning them a higher signal modulus value compared to data subcarriers. This local quality enhancement ensures that phase tracking and frequency offset correction functions receive sufficient energy while maintaining overall system power constraints
Solution Approach 2:
The patent modifies the signal modulus value parameter for pilot subcarriers to optimize frequency offset correction. By changing the first signal modulus value for pilots versus the second signal modulus value for data, the patent improves the reliability of frequency synchronization without causing excessive total power increase that would elevate packet error rates
Data Source
Figure 1~2
Figure 3a
Figure 3b
AI summary
A communication method and apparatus based on a PPDU are provided, are applied to a wireless local area network system that supports 802.11 series protocols such as next-generation Wi-Fi protocols of IEEE 802.11ax like 802.11be, Wi-Fi 7, or EHT, and next generation of 802.1 1be or Wi-Fi 8, and may be further applied to a UWB-based wireless personal area network system, a sensing (sensing) system, and the like. A first communication apparatus generates a PPDU, and sends the PPDU. Correspondingly, a second communication apparatus receives the PPDU, and processes the PPDU based on an index value of a pilot subcarrier. The PPDU includes the pilot subcarrier and a data subcarrier, and a signal modulus value of the pilot subcarrier is greater than a signal modulus value of the data subcarrier. This effectively improves demodulation accuracy of the second communication apparatus.