Transmitter Interference Cancellation for Frequency Reuse

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Solution Overview

Problem

Wireless point-to-point communication systems face interference issues due to the need for different frequencies on communication links with small angular separations, leading to increased costs and potential alternatives like laying landlines.

Innovation Solution

Implementing transmitter interference cancellation methods at the aggregation point, using pre-coding filters and phase shifting to reduce interference between communication beams, allowing for the reuse of the same frequency on previously interfering channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If different frequencies are used on communication links with small angular separations to avoid interference, then interference between links is reduced, but system cost increases and frequency availability decreases

Engineering Contradiction:

Improveinterference between communication linksVSAvoidfrequency allocation complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent changes the parameter of frequency allocation by introducing interference cancellation techniques that allow the same frequency to be reused on links with small angular separations. By applying pre-coding filters and phase shifting, the system modifies the transmission parameters to eliminate interference, enabling frequency reuse without increasing complexity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the harmful interference between communication links into a beneficial situation by using the interfering signal itself as part of the transmission. Through transmitter interference cancellation, the system processes the combined signal containing both desired and interfering components, extracting the desired signal while canceling the interference, thus turning the harmful interference into a manageable signal component

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Adaptability or versatility

If the same frequency is reused on communication links with small angular separations, then frequency availability and cost efficiency improve, but interference between links increases

Engineering Contradiction:

Improvefrequency reuse capabilityVSAvoidinterference between communication links

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by implementing pre-coding filters at the transmitter before signal transmission. These filters pre-process the signals to anticipate and prevent interference from affecting the receiver, allowing frequency reuse by preparing the signals in advance to cancel out potential interference components

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary processing stage at the receiver that handles the combined signal containing both desired and interfering components. The receiver applies signal processing techniques to separate and extract the desired signal from the mixed signal, acting as an intermediary between the interfering transmissions and the final signal extraction

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If transmitter interference cancellation is implemented to enable frequency reuse, then frequency availability improves and costs are reduced, but device complexity increases

Engineering Contradiction:

Improvefrequency reuse capabilityVSAvoidsignal processing complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the signal processing into distinct functional blocks: pre-coding filter stage, phase shifting stage, and signal combination stage. This segmentation allows each component to be optimized independently and implemented using standard signal processing techniques, reducing overall complexity while enabling frequency reuse

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS9008220B2Frequency reuse in wireless point-to-point communication systems

Publication Date: 2015.04.14 CERAGON NETWORKS

AI summary

A method for interference reduction in transmission of at least two single carrier frequency continuous communication beams including producing a first communication signal for a first digital communication link, producing a second communication signal for a second digital communication link, transmitting the first communication signal over a first continuous communication beam at a first frequency, transmitting the second communication signal over a second continuous communication beam at the first frequency, characterized by modifying the first communication signal using transmitter interference cancellation.A method for interference reduction in reception of at least two single carrier frequency continuous communication beams including receiving a first received signal from a first digital communication link, receiving a second received signal from a second digital communication link, modifying the first received signal, adding the modified first received signal to the second received signal, thereby producing a reduced-interference second received signal, characterized by the modifying of the first received signal being based, at least in part, on reducing an error rate of the reduced-interference second received signal.Related apparatus and methods are also described.