Chirp Radio Synchronization Correction Using Phase-Encoded Error Codes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current chirp-modulated radio communication systems, such as LoRa, face limitations in error detection and correction, particularly for time or frequency synchronization errors greater than one sampling period, which can lead to demodulation errors and propagation of errors within data frames.
Innovation Solution
A transmitter and receiver system that incorporates a chirp generator and demodulator with error correction capabilities, using phase encoding and synchronization correction units to detect and correct cyclic shifts and phase differences between chirps, allowing for improved synchronization and error handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional LoRa modulation is used for wireless communication, then power consumption is reduced and communication distance is extended, but error detection and correction capability is insufficient for synchronization errors greater than one sampling period
Solution Approach 1:
The patent embeds error correction information within the existing chirp modulation framework by nesting correction codes in the phase encoding of cyclic shifts. This allows error correction functionality to be integrated into the existing modulation structure without adding separate complex error correction systems, thereby improving reliability while maintaining relatively simple device architecture.
Solution Approach 2:
The patent applies preliminary phase encoding to chirps based on error correction codes before transmission. By pre-encoding the error correction information in the phase of cyclic shifts, the receiver can detect and correct synchronization errors without requiring complex real-time processing, thus improving error detection capability while keeping the receiver architecture simple.
2Reliability
If cyclic shifts are used to encode information in chirp signals, then data transmission is achieved, but synchronization errors greater than one sampling period cannot be detected and are perceived as cyclic shifts causing demodulation errors
Solution Approach 1:
The patent implements a feedback mechanism where the receiver determines cyclic shifts of received chirps relative to a base chirp, uses phase encoding to identify error correction codes, and applies synchronism correction based on this information. This feedback loop enables the system to detect and correct synchronization errors, preventing demodulation errors and information loss even when errors exceed one sampling period.
Solution Approach 2:
By pre-encoding error correction codes in the phase of cyclic shifts before transmission, the patent enables the receiver to preliminarily identify synchronization errors before demodulation. This preliminary error identification allows the system to correct synchronization issues proactively, preventing error propagation and maintaining information integrity.
3Reliability
If error correction codes are included in LoRa data frames, then some errors can be detected and corrected, but errors in opening symbols and first symbols after fading cannot be corrected as errors would propagate to all symbols
Solution Approach 1:
The patent applies preliminary phase encoding to each chirp based on its cyclic shift position, embedding error correction information in the phase domain before transmission. This preliminary encoding ensures that even opening symbols and symbols after fading contain embedded error correction codes that can be independently decoded, preventing error propagation without requiring complex receiver processing.
Solution Approach 2:
The patent applies different phase encoding strategies to different chirps based on their position and cyclic shift characteristics. By tailoring the error correction encoding to local characteristics of each chirp, the system achieves comprehensive error correction coverage including opening symbols, while maintaining simple and consistent receiver processing architecture.
Data Source
AI summary
Transmitter for chirp-modulated radio signals comprising a chirp generator configured to generate a series of chirp signals, wherein each chirp carries an element of information encoded as a cyclic shift, and has a phase encoding an error correction code dependent form the cyclic shift of the chirp, the transmitter further comprising a modulator configured to modulate the series of chirp onto a radio signal and a radio transmitter, transmitting the radio signal. receiver for chirp-modulated radio signals, comprising a clock unit and a demodulator configured for demodulating a series of received chirps signal, the demodulator having a dechirp unit, configured for determining a cyclic shift of each received chirp relative to a base chirp and an error correction code based on a phase of the received chirp, the receiver having a synchronism correction unit configured to detect and/or correct an error in the clock unit based on the error correction code.