Antenna Calibration Using Shared TX RX Circuits
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Solution Overview
Problem
Existing multiple antenna radio communication devices require different hardware configurations for Time Division Duplex (TDD) and Frequency Division Duplex (FDD) systems, leading to inefficiencies such as increased cost, complex design, and reduced accuracy in antenna calibration due to the need for dedicated calibration paths and additional mixers.
Innovation Solution
A radio communication device apparatus and method that uses a single set of TX and RX circuits for both TDD and FDD systems by employing local oscillators to provide different frequencies for antenna TX/RX circuits during normal and calibration operations, allowing the reuse of antenna TX/RX circuits as calibration circuits without introducing extra non-linearity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dedicated calibration paths and additional mixers are introduced for FDD antenna calibration, then antenna calibration can be performed, but hardware complexity and cost increase
Solution Approach 1:
The patent makes the existing TX and RX circuits perform dual functions: normal communication operations and antenna calibration operations. By configuring the TX circuit as a calibration signal generator and the RX circuit as a calibration signal receiver, the system eliminates the need for dedicated calibration hardware paths, thereby reducing hardware complexity while maintaining calibration capability
Solution Approach 2:
The patent merges the calibration function with the existing TX/RX circuits by introducing a switching mechanism. The switch enables the same hardware components to be shared between normal communication mode and calibration mode, consolidating multiple functions into a unified hardware architecture that reduces overall system complexity
2Reliability
If different hardware configurations are used for TDD and FDD antenna calibration, then each system can be optimized, but device adaptability decreases
Solution Approach 1:
The patent creates a universal calibration architecture where the same TX and RX circuits can perform calibration for both TDD and FDD systems. The switching mechanism allows flexible configuration to match different duplexing modes, enabling a single hardware design to adapt to multiple system types without requiring separate dedicated hardware for each mode
Solution Approach 2:
The patent introduces dynamic reconfigurability through switching mechanisms that can adapt the hardware configuration based on the operating mode (TDD or FDD). This dynamic adjustment capability allows the system to optimize its calibration path according to the specific duplexing requirement while maintaining a unified hardware platform
3Reliability
If mixers are added to remedy frequency gaps during antenna calibration, then calibration can be performed, but calibration accuracy deteriorates due to nonlinearity
Solution Approach 1:
The patent extracts and removes the mixer component from the calibration signal path by directly configuring the TX circuit to generate calibration signals at the appropriate frequency. This elimination of the mixer prevents the introduction of nonlinearity and associated distortion products, thereby maintaining higher calibration accuracy while still enabling frequency adaptation through direct digital synthesis or frequency planning
4Reliability
If separate calibration circuits are designed for TDD and FDD, then each system can be optimized, but manufacturing cost increases
Solution Approach 1:
The patent designs a universal calibration circuit that can serve both TDD and FDD systems, eliminating the need to manufacture separate calibration hardware for different duplexing modes. This single-platform approach reduces bill of materials costs, simplifies production lines, and lowers overall manufacturing complexity while maintaining optimized calibration performance for each system type through software or switching configuration
Data Source
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AI summary
The embodiments disclose a method and apparatus for calibrating multiple antennas in a radio communication device. The radio communication device is configured with a TX circuit and a RX circuit for each of the multiple antennas, each pair of the TX circuit and the RX circuit are operably coupled to the corresponding antenna in normal antenna operation. The apparatus comprises a first TX oscillator and a first RX oscillator. The first TX oscillator is operably coupled to the respective TX circuits to supply them with a TX working frequency or a RX calibrating frequency, the TX working frequency is supplied in the normal antenna operation and an antenna TX calibration operation, and the RX calibrating frequency is supplied in an antenna RX calibration operation. The first RX oscillator is operably coupled to the respective RX circuits to supply them with a RX working frequency or a TX calibrating frequency, the RX working frequency is supplied in the normal antenna operation and an antenna RX calibration operation, and the TX calibrating frequency is supplied in an antenna TX calibration operation. In the apparatus, the TX working frequency is the same as TX calibrating frequency, and the RX working frequency is the same as the RX calibrating frequency.