DSP-Based Reconfigurable Diplexer for Hybrid Fiber Coax Band-Split
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Solution Overview
Problem
Conventional diplexers require multiple fixed analog filters to meet various band-split requirements, leading to increased cost, power consumption, and complexity, especially in full-duplex designs.
Innovation Solution
A flexible diplexer design utilizing digital signal processing (DSP) to create reconfigurable filter pairs, allowing for programmable band-split arrangements and additional functionalities like self-interference cancellation and virtual segmentation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple fixed analog filters are used to meet various band-split requirements, then the diplexer can support different bandwidth allocations, but the cost, power consumption, and device complexity increase
Solution Approach 1:
The patent applies dynamics by replacing fixed analog filters with reconfigurable filters that can dynamically adjust their frequency response characteristics. The diplexer transitions from a static configuration with multiple fixed filters to a dynamic system where filter parameters can be changed to accommodate different band-split requirements, thereby reducing the number of physical components needed while maintaining versatility
Solution Approach 2:
The patent implements universality by designing a single reconfigurable diplexer structure that can perform multiple band-split functions. Instead of requiring separate fixed filters for each band-split scenario (sub-split, mid-split, high-split, and various DOCSIS configurations), the reconfigurable filters can be programmed to achieve any of these configurations, making one device serve multiple purposes
2Adaptability or versatility
If multiple fixed analog filters are deployed to accommodate full-duplex designs, then upstream and downstream bandwidths can be allocated flexibly, but power consumption increases
Solution Approach 1:
The patent applies parameter changes by transitioning from fixed analog filter parameters to reconfigurable parameters that can be adjusted via control signals. The reconfigurable filters allow dynamic modification of frequency response characteristics to optimize upstream-downstream bandwidth allocation for full-duplex operation, reducing the need for multiple high-power fixed filters while maintaining flexible bandwidth management capabilities
3Device complexity
If a single reconfigurable diplexer design is used to meet wide range of band-split requirements, then cost and complexity are reduced, but the requirement for dynamic reconfiguration capability increases
Solution Approach 1:
The patent resolves this contradiction by implementing dynamic reconfiguration capability within the filter design. The reconfigurable filters can change their characteristics based on control inputs, allowing a single physical device to adapt to different band-split requirements. This dynamic behavior enables the system to maintain low component count while achieving high adaptability across various DOCSIS configurations and bandwidth allocations
Data Source
AI summary
A flexible diplexer may include a programmably reconfigurable filter pair capable of rendering a variety of band-split arrangements in a digital signal processor (DSP) backed design in hybrid fiber coaxial cable plant/system deployments. The flexible diplexers may thereby meet a larger range of band-split requirements, including the full range of band-split requirements. Configurability may be achieved by digitizing the signal at either input interface of a diplexer in a diplexer/amplifier complex after bandpass filtering, and two-to-four wire conversion at the respective forward (e.g. downstream) and reverse (e.g. upstream) input interfaces. A new band-split may be obtained by updating the digital filters using specified coefficient sets determined off-line and retrieved from memory. The flexible diplexer/amplifier complex may enable the implementation of additional functionality including equalization and tilt regeneration, self-interference cancellation, virtual segmentation, and/or creation of auxiliary service points to provide access to/from a small cell base station and/or Wi-Fi access point.