Backscatter Signal Transmission With Frequency-Domain Separation
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Solution Overview
Problem
The challenge in backscatter communication systems is the low energy of uplink reflection signals from tag devices, leading to a high probability of missing detection by network devices, which affects signal transmission performance.
Innovation Solution
Employing linear frequency modulated signals or multi-carrier linear frequency modulated signals for both downlink excitation and uplink reflection, ensuring they do not overlap in the frequency domain, allowing for frequency domain filtering to separate and enhance signal detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the tag device uses backscatter communication to transmit uplink information, then power consumption is reduced and cost is lowered, but the uplink reflection signal energy becomes too low for reliable detection
Solution Approach 1:
The patent changes the signal waveform parameters by using linear frequency modulated signals or multi-carrier linear frequency modulated signals instead of traditional single-frequency signals. This parameter change enables frequency domain separation between downlink and uplink signals, allowing the network device to filter and detect the weak uplink reflection signal while the tag device continues to operate with low power consumption through backscatter communication.
2Productivity
If the network device receives both downlink excitation signal and uplink reflection signal simultaneously, then communication efficiency is improved, but signal detection becomes difficult due to energy imbalance
Solution Approach 1:
The patent moves the separation of downlink and uplink signals from the time domain to the frequency domain. By using linear frequency modulated signals, the patent creates frequency domain separation where the downlink excitation signal and uplink reflection signal occupy different frequency ranges. This allows the network device to efficiently receive both signals simultaneously while easily separating and detecting them through frequency domain filtering.
3Device complexity
If traditional single-frequency signals are used for downlink excitation, then system complexity is reduced, but frequency domain overlap occurs between downlink and uplink signals
Solution Approach 1:
The patent introduces dynamic frequency modulation where the signal frequency changes linearly over time (linear frequency modulated signals) or uses multiple carriers with different frequencies (multi-carrier linear frequency modulated signals). This dynamic approach enables frequency domain separation between downlink and uplink signals while maintaining relatively simple system implementation, as the frequency modulation follows predictable patterns that can be easily generated and processed.
Data Source
AI summary
This application provides communication apparatuses and methods for signal transmission and reception, applied to, for example, backscatter communications. In an example method, a tag device receives a downlink excitation signal, where the downlink excitation signal is a linear frequency modulated signal or a multi-carrier linear frequency modulated signal. The tag device generates an uplink reflection signal according to the downlink excitation signal and uplink information. The tag device sends the uplink reflection signal to a network device. When receiving the uplink reflection signal from the tag device and receiving the downlink excitation signal, the network device performs fractional Fourier transform on the uplink reflection signal and the downlink excitation signal, to obtain an uplink frequency domain reflection signal and a downlink frequency domain excitation signal. The uplink frequency domain reflection signal and the downlink frequency domain excitation signal do not overlap each other.