Double-Null-Steering Beamforming for IBOC Adjacent Interference
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Solution Overview
Problem
In-band on-channel (IBOC) radio transmission systems face interference issues due to digital sidebands, which affect the reception of digital radio and analog radio broadcast signals transmitted simultaneously on the same frequency, leading to increased interference and reduced signal quality.
Innovation Solution
The method involves selecting time samples from multiple antennas, generating and filtering signals to calculate weighting coefficients that maximize the Signal-to-Interference-plus-Noise-Ratio (SINR), and combining these coefficients with filtered signals to reduce first adjacent interference, using a digital adaptive beam-former and finite impulse response (FIR) filters for improved signal reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If digital sidebands are used to transmit digital information in IBOC system, then digital radio transmission is enabled, but interference is increased
Solution Approach 1:
The patent segments the signal processing into three distinct frequency bands (lower sideband, middle band, upper sideband) and applies separate beamforming weight calculations to each band. This allows independent optimization of interference suppression in each band while maintaining digital transmission capability.
Solution Approach 2:
The patent applies different beamforming weight coefficients to different frequency bands rather than a uniform approach. Specifically, it calculates separate weight coefficients for lower, middle, and upper bands, allowing each band to be optimized for its specific interference characteristics while maintaining overall system performance.
2Object-affected harmful factors
If beam forming with double-null-steering is applied, then adjacent interference is suppressed, but computational complexity increases
Solution Approach 1:
The patent divides the beamforming computation into three separate weight coefficient calculations for lower, middle, and upper bands. Each calculation focuses on a specific frequency range, reducing the computational burden compared to a full-band approach while achieving effective interference suppression.
Solution Approach 2:
The patent applies beamforming weight coefficients selectively to specific frequency bands rather than processing the entire spectrum uniformly. This partial action approach concentrates computational resources on the bands where interference is most problematic, achieving effective suppression with reduced overall complexity.
Data Source
AI summary
Various exemplary embodiments relate to a method for improving reception of transmissions with first adjacent interference signals, the method including selecting one or more time samples from each of two or more antennas; generating a lower first adjacent interference (LFAI) signal, a desired signal, and an upper first adjacent interference (UFAI) signal for each of the time samples; calculating a lower weighting co-efficient based on the LFAI signal; calculating a middle weighting co-efficient based on the desired signal; calculating a upper weighting co-efficient based on the UFAI signal; combining the lower weighting co-efficient with a filtered LFAI signal into a weighted lower signal; combining the middle weighting co-efficient with a filtered desired signal into a weighted middle signal; combining the upper weighting co-efficient with a filtered UFAI signal into a weighted upper signal; and combining the weighted lower signal, the weighted middle signal, and the weighted upper signal.