Antenna Feed Network Switching for RF Channel Calibration
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Solution Overview
Problem
Existing radio frequency channel calibration methods for base station antennas require a dedicated calibration channel, which increases deployment costs and is not compatible with currently deployed Remote Radio Units (RRUs) without additional installation.
Innovation Solution
The method involves using a switch in the feed network between the antenna and RRU to isolate the calibration signal from the main feed signal, allowing for calibration of other radio frequency channels using an existing channel, thereby avoiding interference and eliminating the need for a dedicated calibration channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a dedicated calibration channel is added between antenna and RRU, then phase and amplitude calibration accuracy is improved, but deployment cost and device complexity increase
Solution Approach 1:
The patent makes the existing radio frequency channel serve dual purposes: both normal signal transmission and calibration. By transmitting calibration signals through the same channel used for data communication, the system eliminates the need for separate dedicated calibration channels, thereby reducing deployment complexity while maintaining calibration functionality
Solution Approach 2:
The patent combines the calibration function with the existing radio frequency channel infrastructure. Instead of adding a separate calibration channel, the calibration signals are merged into the same transmission path as normal signals, allowing both functions to coexist in a single channel and reducing overall system complexity
2Measurement precision
If a dedicated calibration channel is added between antenna and RRU, then phase and amplitude calibration accuracy is improved, but compatibility with existing RRU decreases
Solution Approach 1:
The patent enables existing radio frequency channels to perform both normal communication and calibration functions. This multi-functionality ensures compatibility with currently deployed RRUs that lack dedicated calibration channels, as the calibration process utilizes the same infrastructure already present in the system
Solution Approach 2:
The system uses its existing radio frequency channel infrastructure to perform calibration without requiring external dedicated calibration resources. By making the existing channel serve itself for both data transmission and calibration purposes, the system maintains compatibility with standard RRU deployments
3Device complexity
If calibration signal is transmitted through existing radio frequency channel without isolation, then deployment cost is reduced, but calibration accuracy deteriorates due to signal interference
Solution Approach 1:
The patent segments the signal transmission process by introducing time-division multiplexing. Calibration signals and normal data signals are transmitted in different time slots through the same radio frequency channel. This temporal segmentation prevents signal interference while allowing both functions to share the same physical infrastructure
Solution Approach 2:
The patent implements periodic transmission of calibration signals interleaved with normal data transmission. By periodically inserting calibration signals into the transmission schedule and using time-division isolation, the system ensures accurate calibration measurements without continuous interference from data signals
Data Source
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AI summary
This application provides a radio frequency channel calibration method and apparatus, an antenna, and a base station. The antenna includes: at least three radio frequency interfaces and a feed network disposed among the at least three radio frequency interfaces, where each of the at least three radio frequency interfaces is connected to one radio frequency channel between the radio frequency interface and a remote radio unit RRU. A first interface is configured to receive a signal from the RRU, and transmit the signal to a second interface by using the feed network. The second interface is configured to send the signal to the RRU. The feed network includes a main feed circuit, a calibration signal circuit, and a switch. The calibration signal circuit is configured to transmit a calibration signal from the first interface to the second interface, where the calibration signal is used to calibrate a phase and an amplitude of the radio frequency channel connected to the first interface. The switch is configured to isolate the calibration signal from a signal on the main feed circuit. In this application, interference of the signal on the main feed circuit to the calibration signal can be reduced, correctness of a calibration result can be ensured, and various RRU devices can be compatible with.