Remote Antenna Unit Interference Cancellation for Same-Band Tx/Rx
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In distributed antenna systems, especially those operating in 5G New Radio standards, the dynamic and unsynchronized uplink-downlink patterns lead to significant interference in receive signals due to simultaneous transmit and receive operations in the same frequency band, overwhelming the uplink signal with non-linear distortion and amplifier noise from transmit signals.
Innovation Solution
The implementation of a remote antenna unit equipped with isolation circuitry and interference-cancelling circuits, including transmitter-receiver isolation circuits, analog interference-cancellation circuits, and digital interference-cancellation circuits, to reduce interference in receive signals by isolating transmit signals from receivers and cancelling out overlapping transmit and downlink signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If simultaneous transmit and receive operations are performed in the same frequency band, then system productivity and signal coverage are improved, but transmit interference overwhelms the receive signal with non-linear distortion and amplifier noise
Solution Approach 1:
The patent segments the interference cancellation process into multiple stages: analog cancellation circuitry that operates in the analog domain to remove strong transmit signals, followed by digital cancellation circuitry that processes the remaining interference in the digital domain. This multi-stage segmentation allows the system to handle both strong and weak interference components effectively, enabling simultaneous transmit and receive operations without signal overwhelming.
Solution Approach 2:
The patent introduces analog interference-cancellation circuitry as an intermediary component between the transmit and receive paths. This intermediary circuitry generates an analog cancellation signal that mirrors the transmit signal characteristics and subtracts it from the receive signal path, thereby mediating the interference problem and enabling the system to maintain both transmit and receive operations simultaneously.
2Object-affected harmful factors
If traditional TDD mode switching between Tx and Rx is used, then transmit interference is reduced, but adaptability to dynamic 5G uplink-downlink patterns is lost
Solution Approach 1:
The patent implements dynamic interference cancellation that adapts to changing transmit signal conditions in real-time. The analog and digital cancellation circuitry continuously adjust their cancellation signals based on the current transmit signal characteristics, allowing the system to maintain low interference levels even as the transmit patterns dynamically change according to 5G uplink-downlink requirements.
Solution Approach 2:
The patent changes the operational parameters of the cancellation circuitry to match the dynamic 5G patterns. By adjusting the cancellation signal amplitude, phase, and timing parameters in response to changing transmit conditions, the system maintains effective interference reduction while adapting to various uplink-downlink configurations without requiring fixed TDD switching.
3Reliability
If isolation circuitry and interference-cancelling circuits are added, then receive signal quality is improved, but device complexity increases
Solution Approach 1:
The patent merges the interference cancellation functionality directly into the existing receiver architecture by integrating analog and digital cancellation circuitry with the receive signal path. This combining approach allows the system to achieve high receive signal quality while minimizing the addition of separate isolated components, thereby reducing overall device complexity compared to using completely separate isolation systems.
Data Source
AI summary
In an embodiment, a remote antenna unit includes a transmitter, a receiver, an antenna, a first interference circuit, and a second interference circuit. The transmitter is configured to generate a transmit signal, and the receiver configured to process a receive signal. The antenna is coupled to the transmitter and the receiver and is configured to radiate a downlink signal in response to the transmit signal and generate the receive signal in response to an uplink signal. The first interference circuit is coupled to the transmitter and the receiver and is configured to receive an analog signal from the transmitter. The second interference circuit coupled to the transmitter and the receiver. The first interference circuit and the second interference circuit are configured to reduce, in the receive signal, interference caused by the transmit signal and/or at least one downlink signal radiated by an antenna.