Frequency Reuse in Wireless Point-to-Point Links via Interference Cancellation
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Solution Overview
Problem
Wireless point-to-point communication systems face interference issues due to small angular separations between communication links, necessitating the use of different frequencies, which is expensive and often impractical, especially when no additional frequencies are available, leading to potential alternatives like laying landlines.
Innovation Solution
Implementing a method at the aggregation point to reduce interference between communication channels by using a pre-coder with digital FIR filters, which estimates and cancels interference, allowing the same frequency to be reused across previously interfering channels.
Engineering Contradictions & Design Principles
Engineering 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 frequency resources are consumed and costs increase
Solution Approach 1:
The patent changes the parameter of signal processing by applying precoding techniques that modify the transmitted signals to cancel interference. By adjusting the precoder coefficients based on channel state information, the system enables frequency reuse without harmful interference, resolving the contradiction between interference reduction and frequency resource conservation
Solution Approach 2:
The precoder acts as an intermediary device that processes signals before transmission. It introduces intermediate signal components that cancel out the interference that would otherwise be caused by small angular separations, allowing same-frequency links to coexist without harmful interactions
2Quantity of substance
If frequency reuse is implemented on links with small angular separations, then frequency resources are conserved and costs are reduced, but interference between links increases
Solution Approach 1:
The system performs preliminary interference cancellation by applying precoding before signal transmission. The precoder coefficients are calculated in advance based on channel state information, and the precoded signals are transmitted with built-in interference cancellation capabilities, preventing interference before it affects the communication links
Solution Approach 2:
The patent modifies the signal parameters through precoding, transforming the transmitted signals to contain components that actively cancel interference. This parameter transformation enables frequency reuse while maintaining low interference levels, as the precoded signals adapt to the channel conditions and angular separations
Data Source
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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.