Smart Antenna Array Calibration Using Internal Signal Exchange
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Solution Overview
Problem
Existing wireless telecommunication systems require external hardware for calibrating smart antenna arrays, which is inefficient and costly, as they need a separate antenna to send and receive beacon signals for phase and amplitude analysis.
Innovation Solution
A method and system that calibrate the reception and transmit paths of an antenna array connected to a digital signal processor using internal antennas, where each antenna transmits and receives signals to determine and compensate for phase and amplitude differences, eliminating the need for external hardware by utilizing the antenna array itself for calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a separate external antenna is used for calibration, then calibration accuracy can be achieved, but device complexity and cost increase due to additional hardware requirements
Solution Approach 1:
The patent merges the calibration function with the existing antenna array by having each antenna serve dual purposes: normal communication and calibration signal transmission/reception. This eliminates the need for separate calibration hardware while maintaining calibration accuracy through internal signal exchange between array elements.
Solution Approach 2:
Each antenna in the array is designed to perform multiple functions: standard signal transmission/reception during operation, and calibration signal transmission/reception during calibration mode. This multi-functionality removes the requirement for dedicated calibration antennas, reducing overall system complexity.
2Reliability
If external calibration hardware is deployed, then calibration can be performed, but loss of time and resources occur due to hardware rental and setup requirements
Solution Approach 1:
The antenna array performs calibration autonomously using its own internal resources. Each antenna transmits and receives calibration signals sequentially, allowing the system to self-calibrate without external intervention, hardware deployment, or setup time, thereby eliminating resource loss associated with external calibration services.
3Device complexity
If internal antennas are used for calibration, then device complexity is reduced, but measurement precision may be affected by signal interference within the array
Solution Approach 1:
The calibration process segments the measurement into sequential steps where one antenna transmits while others receive, then rotates roles. This time-division approach prevents simultaneous transmission interference, allowing accurate phase and amplitude measurements to be taken without mutual signal contamination.
Solution Approach 2:
The digital signal processor acts as an intermediary that coordinates the calibration sequence, manages signal routing, and processes measurements. It orchestrates which antenna transmits and which receives at each step, ensuring clean signal paths and accurate measurements while maintaining system simplicity.
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 allows for efficient calibration of smart antenna arrays without additional hardware, reducing costs and resource usage, while maintaining high accuracy and adaptability, suitable for systems like WIMAX and TDMA, by using OFDM sub-carriers for signal differentiation.
Implementation Method 1
an electromagnetic signal of known amplitude and known phase is transmitted by a single antenna Tx
Data Source
AI summary
The invention relates to a method of calibrating the reception path and the transmit path of an antenna array which is formed of at least three antennas and which is connected to a digital signal processor. For calibrating the reception path a signal of known amplitude and known phase is transmitted by a single antenna and received by n−1 antennas. For calibrating the transmit path of an antenna array path a signal of known amplitude and known phase is transmitted by n−1 antennas and received by the nth antenna. A phase difference and an amplitude difference between each of the n−1 transmitted signals is evaluated and the steps are repeated with a new transmit antenna until every antenna has been used as a transmit antenna. In the last step the phase differences and their associated amplitude differences are set to the factory-said values.