In-Channel Interference Cancellation Receiver Architecture
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Solution Overview
Problem
In wireless communication systems, out-of-band emissions from broadband transmitters cause significant interference to narrowband receivers, leading to desensitization due to close frequency proximity, despite the presence of guard bands, and retrofitting transmitters to improve filtering is challenging and costly.
Innovation Solution
A communication device with a receiver capable of canceling in-channel interference using multiple filters and an in-channel interference estimator, which generates an estimation signal to combine and partially cancel the interference, thereby minimizing its impact on the desired signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If improved filtering at C band transmitter is used to mitigate interference, then interference in PSNB is reduced, but implementation difficulty and cost increase significantly
Solution Approach 1:
The patent introduces an intermediary system (interference mitigation system) that receives both the C band signal and PSNB signal, processes them together to identify and remove interference components, and outputs a cleaned PSNB signal. This mediator approach avoids the need to modify the C band transmitter while still achieving interference reduction.
Solution Approach 2:
The system creates a copy of the C band signal path and processes it separately to generate an interference estimate, which is then subtracted from the received PSNB signal. This copying approach allows interference cancellation without altering the original transmitter.
2Object-affected harmful factors
If a guard band is included between broadband signal and narrowband signal, then frequency separation is provided, but out-of-band emissions still spill into narrowband frequency band causing receiver desensitization
Solution Approach 1:
The system extracts the out-of-band emission components from the received signal by identifying them as separate interference signals, processing them through dedicated filtering paths, and removing them from the combined signal before final reception. This extraction occurs at the receiver side rather than relying solely on transmitter filtering.
Solution Approach 2:
The received signal is segmented into multiple components: the desired narrowband signal, the out-of-band emissions from the broadband signal, and noise. Each component is processed separately through different filtering and estimation paths, allowing precise removal of interference while preserving the desired signal.
3Productivity
If broadband transmitter operates in close proximity to narrowband receiver, then frequency utilization is maximized, but out-of-band emissions cause considerable interference
Solution Approach 1:
The system uses feedback by continuously monitoring the received signal, estimating the interference components based on the known broadband signal characteristics, and adjusting the cancellation process in real-time. The interference estimate is fed back into the signal processing chain to optimize cancellation performance.
Solution Approach 2:
The system changes parameters by dynamically adjusting filter coefficients, estimation algorithms, and signal processing parameters based on the actual received signal conditions. This allows adaptive optimization of interference cancellation performance while maintaining frequency proximity for efficient spectrum utilization.
Data Source
AI summary
A communication device includes a receiver that is capable of canceling in-channel interference. The receiver includes an antenna for receiving a wireless signal comprising in-channel components and an out-of-channel component, wherein the in-channel components comprise a desired component and an in-channel interference component. A first filter of the receiver filters the wireless signal by blocking at least a portion of the out-of-channel component to produce a first signal comprising the in-channel components, and at least a second filter of the receiver filters the wireless signal by blocking at least a portion of the in-channel components to produce a second signal comprising the out-of-channel component. An in-channel interference estimator of the receiver generates an in-channel interference estimation signal based on the second signal. And a combiner of the filter combines the first signal and the second signal to at least partially cancel the in-channel interference component of the first signal.