Pilot Tone Gain Drift Correction in Wi-Fi Receivers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for measuring gain vs. time in wireless signals, such as Wi-Fi, are time-consuming and costly due to the need for averaging over multiple sweeps, and they introduce errors when using continuous wave signals.
Innovation Solution
Utilizing pilot tones within Wi-Fi signals to measure gain vs. time by comparing power in a long training field (LTF) to power of pilot tones, allowing for accurate and efficient correction of gain changes through demodulation and applying corrections based on temperature and bias current adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If continuous wave signals are used to measure gain vs. time, then measurement can be performed, but measurement precision deteriorates due to introduced errors
Solution Approach 1:
The patent uses pilot tones as intermediary reference signals embedded within the Wi-Fi signal structure. These pilot tones serve as mediators between the transmitted signal and the gain measurement process, providing known reference points at specific time instances that enable accurate gain vs. time measurement without the errors associated with continuous wave signals
Solution Approach 2:
The patent creates a reference copy of the expected signal characteristics through the Long Training Field (LTF) and compares it with the actual received signal containing pilot tones. This copying approach allows for accurate gain measurement by comparing the known reference copy with the measured signal at different time points
2Measurement precision
If averaging over multiple sweeps is performed to measure gain vs. time, then measurement precision improves, but loss of time increases
Solution Approach 1:
The patent performs preliminary action by embedding pilot tones and LTF sequences in advance within the Wi-Fi signal structure before transmission. This preliminary preparation of reference signals within the normal signal flow allows gain measurement to be performed as part of the regular signal processing, eliminating the need for separate time-consuming averaging sweeps
Solution Approach 2:
The patent merges the gain vs. time measurement function with the normal Wi-Fi signal transmission and reception process. By combining the measurement references (LTF and pilot tones) with the data transmission signal, the measurement is performed concurrently with normal operations, eliminating the need for separate dedicated measurement time
3Measurement precision
If existing measurement methods are used, then gain vs. time can be measured, but device complexity increases due to correction circuits and multiple signal processing requirements
Solution Approach 1:
The patent makes the Wi-Fi signal structure universal by incorporating gain measurement references (LTF and pilot tones) that serve multiple functions: normal signal processing, channel estimation, and gain vs. time measurement. This multi-functionality eliminates the need for separate dedicated measurement signals and reduces overall system complexity
Solution Approach 2:
The patent enables the Wi-Fi signal to self-serve the measurement function by including inherent reference elements (pilot tones and LTF) that allow the signal itself to provide the necessary information for gain measurement without requiring external test equipment or separate measurement procedures
Data Source
AI summary
A device may apply a first signal to a device, the first signal comprising a long training field (LTF) and one or more data packets, the one or more data packets comprising one or more pilot tones. A device may demodulate the first signal. A device may compare power in the LTF to power of the one or more pilot tones. A device may determine gain vs. time based at least in part on comparing the power in the LTF to the power of the one or more pilot tones. A device may apply one or more corrections to the device based at least in part on the determined gain vs. time.