Polyphase FFT Transceiver Modules for Jam-Resistant RF Links
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Solution Overview
Problem
Existing broadband data transmission systems for radio communications face challenges in securing and resiliently transmitting RF signals, particularly in applications like police and military radio, where signals need to be difficult to detect and jam-proof.
Innovation Solution
The use of a transmitter module with a synthesis polyphase FFT filter bank and a receiver module with an analysis polyphase FFT filter bank, both employing Nyquist filters and Kasami sequences for secure and resilient data transmission, allowing for simultaneous transmission and reception without interference between sub-channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an analysis filter bank is used in the transmitter module as in the state of the art, then the device complexity is reduced, but signal loss occurs due to oscillator setting times
Solution Approach 1:
The patent inverts the conventional approach by using a synthesis filter bank in the transmitter and an analysis filter bank in the receiver, rather than the traditional analysis-filter approach. This inversion eliminates the need for oscillators with setting times, thereby preventing signal loss and improving transmission reliability.
Solution Approach 2:
The patent replaces the mechanical oscillator-based frequency tuning system with a digital filter bank system. Instead of using oscillators that require setting time to adapt to transmission frequencies, the system uses polyphase FFT filter banks that can instantly switch between frequencies, eliminating the mechanical/inertial limitations of oscillator-based systems.
2Adaptability or versatility
If oscillators are used to adapt to desired transmission frequencies, then frequency tuning is achieved, but signal loss occurs during adjusting/setting times
Solution Approach 1:
The patent replaces the mechanical oscillator system with a digital filter bank system. The polyphase FFT filter banks provide instantaneous frequency switching capability without the setting time inherent in oscillator systems, while maintaining full frequency adaptability through digital control.
Solution Approach 2:
The filter banks are pre-configured with multiple frequency responses, allowing the system to instantly switch to the desired frequency without requiring real-time adjustment. The frequency adaptation is achieved by selecting from pre-computed filter coefficients rather than tuning oscillators in real-time.
3Object-affected harmful factors
If Nyquist filters with steep edges are used, then spectral compactness and interference resistance are improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent uses digital signal processing with polyphase FFT filter banks to achieve Nyquist filtering characteristics. Instead of requiring precise physical implementation of steep-edge filters, the system uses computational algorithms that can be precisely controlled through software, achieving the desired spectral compactness and interference resistance through digital means.
Data Source
AI summary
A transmitter module for a broadband data transmission system for radio communications, comprising at least one polyphase FFT filter bank is described. The at least one polyphase FFT filter bank is established as a synthesis polyphase FFT filter bank, wherein the at least one polyphase FFT filter bank comprises several filter units, wherein the transmitter module is configured to receive an input signal comprising a symbol sequence, and wherein the transmitter module is configured to transmit a signal based on the received input signal. Moreover, a receiver module for a broadband data transmission system and a data transmission system are described.