Directional Beamforming Repeater IF Filtering for Interference Mitigation
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Solution Overview
Problem
Wireless repeaters in millimeter-wave communications face interference issues due to radiation leakage and external jamming, which affect signal quality and stability, especially in environments with physical blockers and jammers.
Innovation Solution
The implementation of directional beamforming repeaters that perform heterodyning to convert received signals to intermediate frequencies, filter out interference, and then upconvert them back to the original frequency for retransmission, using a signal processing chain with a local oscillator tuned by carrier tracking and phase shifters to enhance beamforming and reduce interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If wireless repeaters operate at millimeter-wave frequencies to provide high-speed communication, then communication speed and bandwidth are improved, but signal susceptibility to interference and path loss increases
Solution Approach 1:
The patent introduces an intermediate frequency (IF) stage as a mediator between the millimeter-wave receive path and transmit path. The received mmWave signal is downconverted to IF, where filtering operations are performed, then upconverted back to mmWave for retransmission. This intermediary frequency domain allows for interference mitigation through bandpass filtering while maintaining the high-frequency communication benefits.
Solution Approach 2:
The patent extracts and removes interfering signals from the communication signal by performing bandpass filtering at the intermediate frequency stage. The filter extracts only the desired signal bandwidth centered at the IF frequency, rejecting out-of-band interference including radiation leakage and jammer signals, thereby improving signal reliability before retransmission.
2Area of stationary object
If directional beamforming is used to extend signal coverage, then coverage area is improved, but interference from radiation leakage and external jammers increases
Solution Approach 1:
The intermediate frequency filtering stage acts as an intermediary that separates desired signals from harmful interference. By converting to IF, applying bandpass filtering with centered frequency at the desired signal, and converting back, the system maintains directional beamforming coverage while removing out-of-band interference including radiation leakage and external jammer signals.
Solution Approach 2:
The patent converts the potential harm of operating at millimeter-wave frequencies (susceptibility to interference) into a benefit by using the high frequency's directional characteristics combined with IF filtering. The narrow bandwidth filtering at IF selectively passes the desired beamformed signal while rejecting interference, turning the frequency-related vulnerability into an advantage for interference mitigation.
3Device complexity
If repeaters process signals directly at the original frequency without frequency conversion, then device complexity is reduced, but interference mitigation capability is worsened
Solution Approach 1:
The patent introduces an intermediate frequency as a mediator that enables effective filtering. By downconverting to IF, the desired signal is centered at a lower frequency where bandpass filtering is more effective at rejecting out-of-band interference including radiation leakage. The filtered signal is then upconverted back to the original frequency for retransmission, achieving interference mitigation with manageable complexity.
4Manufacturing precision
If bandpass filtering is applied at intermediate frequency to reduce interference, then signal purity is improved, but device complexity and processing steps increase
Solution Approach 1:
The intermediate frequency serves as an intermediary domain where bandpass filtering achieves superior signal purity. The heterodyning process to IF, followed by bandpass filtering centered at the IF frequency, and subsequent upconversion creates an effective interference rejection mechanism. This intermediary approach provides better filtering performance compared to direct RF filtering while keeping the overall system complexity manageable through standardized frequency conversion techniques.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach improves signal reliability and stability by filtering out interference, allowing for reliable communications even in non-line-of-sight scenarios and reducing the impact of jammers and physical blockers, while also simplifying components and reducing costs by operating at lower frequencies.
Implementation Method 1
The repeater may perform heterodyning or downconverting on the received signal to reduce a frequency of the signal from the first frequency to an intermediate frequency (IF)
Implementation Method 2
then band-pass filter the IF signal around a desired center frequency
Implementation Method 3
The repeater may heterodyne or upconvert the filtered IF signal back to the first frequency for the retransmission of the signal
Implementation Method 4
receiving, at a first antenna array of a wireless repeater via directional beamforming, a first signal at a first frequency
Data Source
AI summary
Methods, systems, and devices for wireless communications are described that provide a repeater for beamforming a received signal at a first radio frequency via one or more scan angles or beamforming directions and then retransmitting and beamforming the transmitted signal at the first radio frequency via one or more scan angles or beamforming directions. Repeaters may perform heterodyning or downconverting on the received signal to reduce a frequency of the signal from the first frequency to an intermediate frequency (IF), and then band-pass filter the IF signal around a desired center frequency. The repeater may then heterodyne or upconvert the filtered IF signal back to the first frequency for the retransmission of the signal.