Directional Diversity Transmission for Shared-Spectrum Networks

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Solution Overview

Problem

Communication networks face bandwidth limitations due to the inability to efficiently utilize allocated and unallocated frequency spectrum, leading to interference between different services and suboptimal utilization of available bandwidth.

Innovation Solution

Implementing directional diversity techniques using non-reciprocal coupling devices like circulators and feed-forward interference cancellation to transmit downstream and upstream signals in opposite directions over the same radio frequency spectrum, allowing simultaneous use of unassigned frequency ranges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the same frequency spectrum is used for both upstream and downstream communications, then bandwidth utilization is improved, but signal interference between upstream and downstream increases

Engineering Contradiction:

Improvebandwidth utilizationVSAvoidsignal interference

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the frequency spectrum into different bands for upstream and downstream communications. Specifically, it allocates certain frequency ranges to upstream signals and other frequency ranges to downstream signals, allowing simultaneous transmission without mutual interference. This segmentation enables efficient bandwidth utilization while preventing the harmful interference that would occur if the same spectrum was used for both directions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary device (such as a circulator or directional coupler) that mediates between upstream and downstream signals. These intermediary components enable the system to distinguish between signals traveling in opposite directions and route them appropriately, allowing both upstream and downstream communications to share the frequency spectrum without direct interference.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If non-reciprocal coupling devices are used to isolate upstream and downstream signals, then signal interference is reduced, but device complexity increases

Engineering Contradiction:

Improvesignal interferenceVSAvoiddevice complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent employs intermediary devices such as circulators and directional couplers to isolate upstream and downstream signals. These devices act as mediators that enable frequency sharing while preventing interference. Although they add some device complexity, they are standard components in communication systems and provide effective signal separation without requiring overly complex architectures.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent utilizes feedback mechanisms where the system monitors signal conditions and adjusts operations accordingly. This feedback approach allows the system to manage interference dynamically, compensating for the complexity introduced by isolation devices through intelligent signal processing and adaptive resource allocation.

Inventive Principle:

Principle #23Feedback

3Object-affected harmful factors

If feed-forward interference cancellation is implemented, then signal isolation between upstream and downstream is improved, but system complexity increases

Engineering Contradiction:

Improvesignal isolationVSAvoidsystem complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent implements feed-forward interference cancellation by performing preliminary actions to prevent interference before it occurs. The system anticipates potential interference patterns and pre-computes cancellation signals or adjusts transmission parameters in advance. This preliminary action approach improves signal isolation between upstream and downstream communications while managing system complexity through proactive rather than reactive interference management.

Inventive Principle:

Principle #10Preliminary action

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

Enhances bandwidth utilization by isolating upstream and downstream signals, enabling efficient use of unallocated frequency spectrum and reducing interference, thereby supporting multiple services concurrently.

Implementation Method 1

Non-reciprocal coupling devices, such as circulators, may be configured in the network to provide unidirectional transmission of each signal or groups of signals to prevent interference

Methodology Applied

Scientific EffectNon-reciprocal coupling:

Implementation Method 2

feed-forward interference cancellation may be utilized to increase signal isolation of upstream and downstream signals

Methodology Applied

Scientific EffectInterference cancellation: Interference

Data Source

PatentUS12418388B2Transmitting signals using directional diversity over a network

Publication Date: 2025.09.16 COMCAST CABLE COMM LLC

AI summary

Methods and systems are disclosed for using a common frequency spectrum for simultaneous upstream and downstream communications in a network by implementing directional diversity techniques. Non-reciprocal coupling devices, such as circulators, may be configured in the network to provide unidirectional transmission of each signal to prevent interference. In some embodiments, feed-forward interference cancellation is utilized to increase signal isolation of upstream and downstream signals.