Backscatter Transceiver Dual Signal Segmentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In RFID systems, especially those using backscatter modulation at UHF frequencies, there is a challenge in detecting and separating the transponder signal from the carrier signal due to a low Signal-to-Carrier ratio and Signal-to-Noise ratio, which limits the amplification and filtering capabilities, resulting in a reduced reading range.
Innovation Solution
A transceiver system that sends a signal with two independent signal portions, where one signal is modulated with data and the other supports carrier suppression, allowing for improved filtering and amplification, enabling effective demodulation of the transponder signal without overdriving the Low Noise Amplifier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If homodyne receiving architectures are used to filter and amplify the transponder signal in the base band range, then the transponder signal can be demodulated, but the reading range is reduced due to loss of range
Solution Approach 1:
The transmit signal is segmented into two independent signal portions: a first signal portion that is not modulated with data (serving as a reference) and a second signal portion that is modulated with data. This segmentation allows the receiver to separate and process the data-containing portion while using the reference portion for carrier suppression and synchronization, enabling better signal detection without sacrificing reading range
Solution Approach 2:
The first signal portion acts as an intermediary reference signal that mediates between the strong carrier and the weak modulated signal. By providing this reference signal, the system can perform accurate carrier suppression and synchronization, allowing the second signal portion to be detected with improved SNR while maintaining the reading range
2Ease of manufacture
If an auxiliary carrier is used to shift the transponder signal spectrally, then the transponder signal can be filtered out easily, but the energy demand of the transponder increases significantly
Solution Approach 1:
Instead of having the transponder generate an auxiliary carrier to shift its signal (as in conventional approaches), the reading device generates both signal portions and transmits them to the transponder. The transponder simply modulates both portions and returns them, inverting the problem from transponder-side signal generation to reader-side signal generation, thereby reducing transponder energy consumption
Solution Approach 2:
The reading device performs the complex signal generation and processing functions for itself by transmitting the two independent signal portions and processing the combined return signal. This self-service approach eliminates the need for the energy-constrained transponder to generate auxiliary carriers, as all signal processing is handled by the reading device
3Measurement precision
If the amplitude of the carrier signal is decreased by hardware or software, then the SCR improves and error-free demodulation is enabled, but the system complexity increases
Solution Approach 1:
The system changes the parameters of the transmitted signal by using two independent signal portions with different characteristics (one modulated, one not modulated with data). This parameter change allows the receiver to extract the data from the second portion while using the first portion for reference, achieving accurate demodulation through signal structure modification rather than complex carrier suppression algorithms
Data Source
AI summary
Embodiments relate to a transceiver configured to send a send signal to a radio module having a backscatter modulator or a load modulator, the send signal including two different signal portions based on mutually independent signals or signal sources.