Bandpass Filter Asymmetric Rolloff Signal Interference
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Solution Overview
Problem
Modern cellular communication networks face inefficiencies due to mismatched filtering between transmitting and receiving devices, particularly when reducing carrier spacing, leading to interference and information loss, which complicates the management of communication resources and spectral mask compliance.
Innovation Solution
Configuring bandpass filtering to compensate for signal losses by adding gain in the passband region, specifically within the Nyquist zone, to achieve compatibility with existing filtering mechanisms and reduce rolloff regions, thereby preventing interference and ensuring efficient signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If carrier spacing is reduced to increase spectral efficiency, then productivity is improved, but interference between carriers increases due to overlapping rolloff regions
Solution Approach 1:
The patent modifies the filtering parameters by applying different rolloff factors to different carriers. Specifically, one carrier uses a first rolloff factor while another carrier uses a second rolloff factor, allowing the system to reduce carrier spacing and increase spectral efficiency while maintaining acceptable interference levels through asymmetric filtering characteristics
2Productivity
If asymmetric rolloff factors are applied to different carriers, then spectral efficiency is improved, but mismatched filtering between transmitting and receiving devices causes signal loss
Solution Approach 1:
The patent employs a composite filtering approach where the overall filtering function is divided into two distinct filtering functions: a first filtering function applied at the transmitting device and a second filtering function applied at the receiving device. These filtering functions have different rolloff factors but are specifically designed to be complementary, ensuring that their combined effect achieves the desired asymmetric spectral efficiency while preserving all signal components without loss
Solution Approach 2:
The patent implements a feedback mechanism where the receiving device determines the filtering function used by the transmitting device and communicates this information back. Based on this feedback, the receiving device configures its filtering function accordingly to ensure compatibility and prevent signal loss, enabling dynamic adaptation to asymmetric filtering requirements
3Productivity
If filtering is matched between transmitting and receiving devices, then transmission efficiency is maximized, but adaptability to different carrier configurations is reduced
Solution Approach 1:
The patent introduces dynamic adaptability by allowing the filtering configuration to change based on the specific carrier arrangement. The system can dynamically select and apply different filtering functions with appropriate rolloff factors depending on the number of carriers, their spacing, and frequency allocations, enabling the same system to optimize transmission efficiency for various carrier configurations rather than being locked into a fixed matched filtering approach
Data Source
AI summary
Systems and techniques for signal filtering are described. A bandpass filter is defined so as to provide for a reduced rolloff region so as to avoid interference with an adjacent carrier. Definition of the bandpass filter provides for a frequency response that compensates for loss of signal components in the rolloff region. Definition of the bandpass filter may be based at least in part on characteristics of a specified legacy filter used by devices from which signals may be received or to which signals may be transmitted.