RF Cable Power Compensation via Automatic Loss Measurement
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Solution Overview
Problem
In Wi-Fi deployments, especially outdoor environments, unbalanced transmission (TX) power across radio frequency (RF) chains due to unknown RF cable loss, aging antennas, or loose installations affects MIMO transmission performance and efficiency, necessitating a solution for automatic power compensation.
Innovation Solution
An access point (AP) determines a time slot for RF cable loss measurement, transmits a test signal, and calculates power compensation based on the measured loss and antenna gain to balance TX power across RF chains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If outdoor Wi-Fi access points are installed to extend coverage, then Wi-Fi coverage area is improved, but signal attenuation and unbalanced TX power occur due to RF cable loss
Solution Approach 1:
The system performs preliminary measurement of RF cable loss by transmitting test signals through the RF cables before normal operation. The AP measures the power of received test signals from antenna modules to calculate cable loss values, which are then stored and used for power compensation during actual Wi-Fi transmission, thereby pre-compensating for the expected signal attenuation.
Solution Approach 2:
The system implements feedback by continuously monitoring the power of test signals received from antenna modules through RF cables. The measured power values are fed back to the AP, which calculates the actual cable loss and adjusts transmission power accordingly. This closed-loop feedback mechanism ensures that power compensation adapts to actual cable conditions, maintaining balanced TX power across all RF chains despite varying cable losses.
2Speed
If MIMO technology is implemented to increase data transfer rates, then transmission speed is improved, but transmission performance deteriorates due to unbalanced TX power across RF chains
Solution Approach 1:
The system applies local quality by individually measuring and compensating for RF cable loss in each RF chain rather than using a uniform compensation value. Each antenna module's connected RF cable is tested separately, and specific power compensation is calculated for each chain based on its unique loss characteristics. This ensures that each RF chain in the MIMO system has balanced and optimized transmission power, maintaining overall MIMO performance.
Solution Approach 2:
The system changes the transmission power parameter dynamically based on measured cable loss. The AP adjusts the TX power for each RF chain by adding the measured cable loss value to the desired output power, thereby compensating for cable attenuation. This parameter adjustment ensures that all RF chains operate at balanced power levels, optimizing MIMO transmission performance and data transfer rates.
3Measurement precision
If manual RF cable loss measurement is performed to determine power compensation, then measurement precision is improved, but operation complexity and time consumption increase
Solution Approach 1:
The system implements self-service by enabling the access point to automatically measure RF cable loss without requiring external measurement equipment or manual intervention. The AP transmits test signals through the RF cables and measures the power of signals received from antenna modules to calculate cable loss values autonomously. This self-measurement capability eliminates the need for external power meters or manual measurement procedures, significantly reducing measurement time while maintaining precision.
Solution Approach 2:
The system achieves universality by using the existing Wi-Fi communication infrastructure for dual purposes: normal data transmission and RF cable loss measurement. The same RF cables, antenna modules, and signal processing paths used for Wi-Fi communication are utilized to measure cable loss. This multi-functionality eliminates the need for separate measurement equipment and procedures, reducing both time and complexity while maintaining measurement accuracy.
Data Source
AI summary
In implementations of the present disclosure, a power compensation determination for radio frequency cable mechanism is provided. An access point (AP) determines a time slot for an RF cable loss measurement on an RF cable, and transmits a test signal with a first TX power to an antenna module over the RF cable. The AP further obtains a second TX power transmitted by the antenna module, and determines an RF cable loss based on the first TX power and the second TX power. The AP further determines power compensation for the RF cable based on the determined RF cable loss, the first TX power and an antenna gain of the antenna module. The AP transmits signals on the RF cable to the antenna module based on the determined power compensation. Implementations of the present disclosure can determine the power compensation based on the RF cable loss automatically.