Interference Cancellation in Distributed Antenna Systems
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Solution Overview
Problem
In distributed antenna systems, intermodulation distortion occurs due to passive elements, particularly in multi-band services, leading to nonlinear characteristics in uplink bands caused by downlink communication signals, which existing methods fail to effectively address.
Innovation Solution
The system generates an interference cancellation signal by feeding back a downlink communication signal subjected to analog signal processing and reflecting signal modification information to cancel interference in uplink signals, utilizing a pseudo-interference signal generator and interference canceler to compensate for signal changes and reduce passive intermodulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a distributed antenna system provides multi-band service, then service capability is improved, but intermodulation distortion increases due to nonlinear characteristics in passive elements
Solution Approach 1:
The patent feeds back the downlink communication signal through the same passive elements that cause intermodulation distortion, allowing the system to capture the actual distortion characteristics. This captured distortion information is then used to generate cancellation signals that eliminate the harmful intermodulation effects in uplink reception, effectively converting the harmful nonlinear characteristics into useful information for distortion cancellation
Solution Approach 2:
The system implements a feedback mechanism where the downlink communication signal is transmitted through the passive elements and the resulting distorted signal is fed back to the base station. This feedback loop enables the system to learn the actual nonlinear characteristics of the passive elements and use this information to generate accurate interference cancellation signals for removing intermodulation distortion
2Productivity
If downlink communication signals are transmitted through passive elements, then signal distribution is improved, but nonlinear characteristics cause interference in uplink bands
Solution Approach 1:
The patent utilizes the downlink signal passing through passive elements to capture the actual distortion introduced by these elements. By feeding back this distorted signal and extracting distortion information, the system converts the harmful nonlinear effect into useful data for generating cancellation signals that eliminate uplink interference caused by the same passive elements
3Reliability
If existing interference cancellation methods are used, then basic interference reduction is achieved, but intermodulation distortion in multi-band services cannot be effectively addressed
Solution Approach 1:
The patent specifically addresses passive intermodulation distortion by feeding back the downlink signal through the passive elements and capturing the actual distortion characteristics. This approach enables the system to generate targeted cancellation signals that effectively remove passive intermodulation interference, significantly improving interference cancellation effectiveness for multi-band services where traditional methods fail
Solution Approach 2:
The system implements feedback of the downlink communication signal through the passive elements to capture actual distortion characteristics. This feedback mechanism enables the base station to learn the specific nonlinear characteristics of the passive elements and generate accurate cancellation signals tailored to remove passive intermodulation distortion, making the interference cancellation effective for multi-band services
Data Source
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AI summary
A method of operating a communication device including a processor and a memory, the method comprises feeding back a downlink communication signal subjected to analog signal processing, generating signal modification information according to a comparison result of the fed-back downlink communication signal and a downlink communication signal before the analog signal processing, generating an interference cancellation signal for canceling interference occurring in an uplink communication signal by the downlink communication signal based on the generated signal modification information and canceling interference occurring in the uplink communication signal by using the generated interference cancellation signal.