Preamble-Based Transmit Power Detection for Wi-Fi OFDM Signals
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Solution Overview
Problem
Existing methods for measuring transmit power in wireless communication systems, particularly for Wi-Fi OFDM signals, face challenges with high peak-to-average power ratio (PAPR) signals, requiring high sampling rates and long data packet lengths, which can disrupt media access control (MAC) flows and complicate power control.
Innovation Solution
A preamble-based transmission power detection method using a directional coupler and a detector circuit to sample and integrate the transmit power over a defined period within the preamble of Wi-Fi OFDM data packets, allowing for accurate power measurement with minimal impact on actual transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high sampling rate is used to measure transmit power of OFDM signals, then measurement precision is improved, but device complexity and processing requirements increase
Solution Approach 1:
The patent segments the OFDM signal measurement process by focusing only on the preamble portion rather than the entire data packet. The preamble contains training symbols that are known sequences, allowing for accurate power measurement without needing to process the high-rate entire signal. This segmentation enables lower sampling rates while maintaining measurement precision.
Solution Approach 2:
The patent applies partial action by measuring power only during the preamble period rather than throughout the entire data packet transmission. This partial measurement approach provides sufficient accuracy for power control purposes without requiring continuous high-rate sampling, thereby reducing device complexity and processing requirements.
2Measurement precision
If long data packet length is used for power measurement, then measurement precision is improved, but productivity and MAC flow efficiency deteriorate
Solution Approach 1:
The patent extracts the measurement function from the entire data packet and isolates it to the preamble portion. By taking out only the necessary preamble segment for power measurement, the system achieves accurate measurements without requiring extended packet lengths, thus maintaining MAC flow efficiency and productivity.
Solution Approach 2:
The patent uses partial action by performing power measurement only during the preamble period rather than requiring long data packet lengths. This approach provides sufficient measurement precision for power control while minimizing impact on MAC flow efficiency and overall system productivity.
3Measurement precision
If measurement processing is performed on entire data packet, then measurement precision is improved, but loss of time increases due to MAC flow disruptions
Solution Approach 1:
The patent segments the measurement process to operate only on the preamble portion of the signal, which is transmitted before the actual data packet. This timing segmentation allows power measurement to occur without disrupting the main data transmission flow, reducing time loss while maintaining measurement precision through focused processing.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach provides accurate transmit power measurement with reduced processing complexity and minimal disruption to MAC flows, enabling efficient power control and calibration in wireless communication devices.
Implementation Method 1
A directional coupler may be utilized to signal sample transmit power of the transmitted data packets
Implementation Method 2
a radio frequency (RF) signal (at a power amplifier (PA) output) passes through an envelope detector (or a self-mixer)
Implementation Method 3
The voltage output is subsequently integrated within a defined (or accurate) period of time
Data Source
AI summary
Described herein are technologies related to an implementation of transmission power detection in a communication device. The portion of a data signal, and in certain implementations the preamble, of the data signal is used in providing an integrated signal output to determine actual transmission power.