DAS Interference Control via Centralized Adjustment Circuits
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Solution Overview
Problem
Distributed antenna systems (DAS) face interference issues due to leaked downlink interference signals in the uplink path, which degrade communication quality and increase costs when attempting to isolate these signals with high isolation RF filters in each remote antenna unit (RAU).
Innovation Solution
An interference control system outside of the RAUs monitors and controls adjustment circuits in the RAUs to minimize downlink interference signals in the uplink path, using a signal generator, spectrum analyzer, and process controller to measure and adjust the signal strength, thereby reducing interference without the need for costly filters in each RAU.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If high isolation RF filters are used in each RAU to isolate downlink interference signals, then interference isolation is improved, but device cost increases
Solution Approach 1:
The patent extracts the interference control function from individual RAUs and consolidates it at the central controller level. The spectrum analyzer and signal generator are deployed centrally to monitor and measure interference signals, eliminating the need for expensive RF filters in each remote unit while maintaining effective interference isolation.
Solution Approach 2:
The patent introduces an intermediary control system consisting of a central controller, spectrum analyzer, and signal generator that mediates between the downlink signal and the uplink path. This intermediary system measures and controls interference signals without requiring physical isolation components in each RAU, thereby reducing device cost while maintaining interference isolation performance.
2Object-affected harmful factors
If interference control systems are provided in each RAU to reduce leaked downlink interference signals, then interference reduction is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple interference control functions into a single centralized system. The spectrum analyzer, signal generator, and control logic are combined in one central controller that manages interference across all RAUs, eliminating the need for duplicate interference control systems in each remote unit and thereby reducing overall system complexity.
Solution Approach 2:
The central controller serves multiple functions: it acts as the spectrum analyzer to detect interference, the signal generator to create test signals, the controller to process measurements, and the coordinator to manage all RAUs. This multi-functional universal system replaces what would otherwise require separate dedicated interference control systems in each RAU, reducing complexity.
3Power
If signal amplifier is used to amplify downlink communications signals, then signal strength is improved, but intermodulation products are generated
Solution Approach 1:
The patent implements a feedback mechanism where the spectrum analyzer continuously monitors intermodulation products generated by the signal amplifier, and the central controller adjusts the amplifier operation or signal generation accordingly. This feedback loop enables the system to maintain adequate signal strength while controlling and minimizing harmful intermodulation products through active management.
Data Source
AI summary
Methods and systems for reducing leaked downlink interference signals in a remote unit uplink path(s) in a distributed antenna system (DAS) are provided. In a remote antenna unit (RAU) disclosed herein, a downlink interference signal may be leaked from a downlink path to an uplink path in the RAU. In this regard, an adjustment circuit is provided in the downlink path of the RAU to suppress the downlink interference signal. A control system is provided in the DAS to monitor the leaked downlink interference signal and control the adjustment circuit in the RAU to minimize the leaked downlink interference signal in the uplink path. By providing the adjustment circuit in the RAU and the control system in the DAS to minimize the leaked downlink interference signal in the uplink path, it is possible to reduce interferences between downlink and uplink communications signals without increasing costs of the RAU.