Orthogonal Chirp Waveforms for Multi-User Radar and Communication
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Solution Overview
Problem
Current wireless communication, radar, and navigation systems require separate hardware and transceivers, leading to inefficient bandwidth usage and increased costs due to the need for distinct communication and ranging/navigation systems, especially in environments with limited spectrum availability.
Innovation Solution
The implementation of orthogonal chirp waveforms for multi-user communication systems that enable simultaneous communication, radar, and relative navigation using a single platform, allowing for spectrum sharing and reduced hardware complexity by employing Fourier-based orthogonal chirp sequences for encoding and decoding messages, which are orthogonal for various circular shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate hardware and transceiver systems are used for communication and radar/navigation, then system reliability and functionality are improved, but device complexity and cost increase
Solution Approach 1:
The patent combines communication and radar/navigation functions into a single integrated system that uses the same hardware platform, transceiver, and waveform generation infrastructure. The orthogonal chirp waveform serves dual purposes: enabling multi-user communication while simultaneously providing radar detection and ranging capabilities, thereby eliminating the need for separate hardware systems.
Solution Approach 2:
The patent creates a universal waveform platform that performs multiple functions simultaneously. The orthogonal chirp sequence is designed to support both communication (data transmission between users) and sensing (radar detection and ranging) operations using the same hardware resources, making the system multi-functional rather than requiring dedicated systems for each function.
2Reliability
If separate communication and radar systems are deployed, then performance for each function is optimized, but bandwidth utilization efficiency deteriorates
Solution Approach 1:
The patent merges communication and radar operations into a single shared spectrum resource. The same frequency band and time slot are used for both communication data transmission and radar sensing, with the orthogonal chirp waveform carrying both functions simultaneously, thereby improving bandwidth utilization efficiency.
Solution Approach 2:
The universal orthogonal chirp waveform enables the system to perform both communication and radar functions within the same bandwidth allocation. By designing the waveform to support multiple functions concurrently, the patent achieves spectrum sharing that improves overall bandwidth efficiency compared to dedicated separate systems.
3Productivity
If multiple users share the same spectrum, then spectrum utilization is improved, but interference between users increases
Solution Approach 1:
The patent assigns different orthogonal chirp sequences with unique local properties to different users. Each user's waveform has distinct autocorrelation and cross-correlation characteristics, where the local quality of each sequence's correlation properties enables users to be distinguished from one another, reducing interference while allowing spectrum sharing.
Solution Approach 2:
The patent uses parameter changes in the orthogonal chirp sequences (such as different chirp rates, frequencies, or phase characteristics) to differentiate between users. By varying these parameters while maintaining orthogonality, the system allows multiple users to share the same spectrum without significant interference, as each user's signal can be independently detected through correlation processing.
Data Source
AI summary
A multi-user system to simultaneously perform operations such as communication, RADAR, Light Detection and Ranging (LIDAR) and Relative Navigation (RELNAV). The techniques according to an embodiment includes generating a Fourier based orthogonal chirp sequence of length P, a prime number greater than the number of users targeted for communication. The orthogonal chirp sequence is based on an identifier, in the range of one to P−1, associated with one of the targeted users. The method further includes using the orthogonal chirp sequence to generate a spread user signal based on a message directed to the one targeted users. The method further includes generating a sequence of training pulses for insertion into the spread user signal to facilitate reception of the signal. The method further includes transmitting and receiving a reflection of the spread user signal from one of the targeted users, the reflection used to detect and range the user.