Antenna Array Calibration via Latency Mismatch Correction
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Solution Overview
Problem
Current antenna array technologies in wireless communication systems face challenges with signal latency mismatch and phase coherence issues due to increased symbol rates in modern air-interface protocols, leading to suboptimal beam-forming and calibration, particularly in 3G and UMTS systems, where conventional calibration methods are inadequate and can degrade network performance during live transmissions.
Innovation Solution
A network element with independent transceiver circuits and a switched coupler structure is introduced, allowing for latency determination and correction across multiple antenna elements, using feedback paths to normalize latency and apply correction coefficients to beamformer logic, thereby addressing latency mismatch and phase coherence issues in real-time without degrading network performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional calibration methods are used during live transmissions, then calibration can be performed, but network performance degrades
Solution Approach 1:
The calibration process is segmented into separate calibration signal paths and live traffic signal paths. The calibration signals are injected through specific couplers (e.g., coupler 408, 414) that are isolated from the main signal flow during live operations, allowing calibration to proceed without interfering with or degrading live network performance.
Solution Approach 2:
Dedicated calibration couplers and feedback paths act as intermediaries between the calibration signals and the antenna array. These intermediary components allow calibration signals to be injected and measured without directly interfering with live traffic signals, enabling simultaneous calibration and operation.
2Measurement precision
If multiple feedback paths are used for calibration, then latency determination accuracy improves, but device complexity increases
Solution Approach 1:
The system uses multiple feedback paths (excessive action) to measure latency, where at least two different feedback paths provide redundant measurement opportunities. This excess of measurement paths enables more accurate latency determination by allowing comparison and normalization across multiple signal travel paths, outweighing the added structural complexity.
3Measurement precision
If latency correction is applied in real-time during live operations, then beam-forming accuracy improves, but processing complexity increases
Solution Approach 1:
Latency correction coefficients are determined and stored in advance during calibration phases, before live beam-forming operations begin. The beam-forming processor then applies these pre-calculated correction coefficients to the antenna array signals, avoiding the need for complex real-time latency calculations during live operations and reducing processing complexity while maintaining accuracy.
4Measurement precision
If independent transceiver circuits are used for each antenna element, then calibration precision improves, but device complexity increases
Solution Approach 1:
The independent transceiver circuits are designed with multi-functionality, serving both calibration operations and live traffic signal processing. Each transceiver circuit can handle calibration signals when injected through the dedicated couplers and normal traffic signals during operations, eliminating the need for separate calibration-only hardware and reducing overall device complexity while maintaining calibration precision.
Data Source
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AI summary
A network element for a wireless communication system is locatable to couple at least one base station to an antenna array comprising a plurality of antenna elements. The network element comprises a plurality of independent transceiver circuits coupled to at least one of a plurality of respective antenna elements of the antenna array; and logic arranged to apply at least one complex digital signal to at least one transceiver signal path of a transceiver circuit of the plurality of independent transceiver circuits. A feedback path is arranged to provide feedback of the at least one complex digital signal such that it is capable of facilitating determination of latency mismatch error response between at least two transceiver signal paths. Adjustment means comprises delay logic arranged to receive a complex digital signal and provide a modified representation of the received complex digital signal in response to the latency mismatch error response of the at least two transceiver signal path.