DSRC On-Board Unit Filtering for Multi-Beacon Signals
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Solution Overview
Problem
Existing OBUs for DSRC communication with multiple beacons are either complex and unreliable or require high power consumption due to interference from unwanted frequencies and channels.
Innovation Solution
The OBU filters out unwanted frequencies and channels by downconverting and upconverting signals to intermediate band or baseband, allowing reliable communication with multiple beacons while reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the OBU determines the strongest request signal to answer only in that channel, then transmitting power is reduced, but device complexity increases and reliability decreases
Solution Approach 1:
The patent extracts and processes only the desired beacon channels from the received signal by downconverting to baseband and applying bandpass filters tuned to specific beacon frequencies. This selective extraction avoids the complexity of determining signal strength and identifying the strongest beacon, while still achieving power savings by transmitting only on filtered channels.
Solution Approach 2:
The patent introduces an intermediate baseband frequency stage between receiving the RF signal and transmitting the response. By downconverting to baseband and processing signals there, the system simplifies frequency management and channel selection without requiring complex signal strength analysis hardware.
2Device complexity
If the OBU indifferently modulates response onto all received carrier signals, then hardware complexity is reduced, but power consumption increases due to processing unwanted signals
Solution Approach 1:
The patent extracts only the desired beacon channels from the mixed RF signal by downconverting to baseband and applying bandpass filters. This selective extraction eliminates unwanted frequencies (WLAN, Bluetooth, ZigBee, Z-Wave) before modulation, reducing power consumption while maintaining simple hardware architecture.
Solution Approach 2:
The patent applies different processing treatments to different frequency components: desired beacon channels are filtered and processed, while unwanted frequencies are rejected. This local quality approach allows simple hardware to achieve power efficiency by treating different signal components differently based on their frequency characteristics.
3Reliability
If the OBU processes signals from all channels including unwanted frequencies, then communication coverage is maintained, but channel crosstalk increases and power consumption rises
Solution Approach 1:
The patent extracts only the desired beacon channels by downconverting to baseband and applying bandpass filters tuned to specific beacon frequencies. This extraction removes unwanted frequencies that would cause channel crosstalk, maintaining communication reliability with filtered beacons while eliminating interference from other channels.
Solution Approach 2:
The patent converts the potentially harmful effect of receiving all frequencies into a benefit by using the downconversion and filtering process to selectively isolate desired signals. The filtering stage transforms the mixed signal containing harmful crosstalk into clean, separated channels, turning the challenge of signal diversity into an advantage for reliable communication.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method ensures reliable communication with all beacons by filtering out unwanted frequencies, thereby reducing power consumption and minimizing crosstalk.
Implementation Method 1
downconverting, by an input converter, the receive signal to obtain a downconverted signal
Implementation Method 2
filtering, by an input filter, all of said different channels out of the downconverted signal to obtain a filtered signal
Implementation Method 3
modulating, by a modulator, an OBU response onto the filtered signal to obtain a response signal
Implementation Method 4
upconverting, by an output converter, the response signal to obtain an upconverted signal
Data Source
Figure 1~2
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Figure 8~10
AI summary
A method (35) for dedicated short-range communication, DSRC, of an on-board unit, OBU, (1) with at least two beacons (71 - 7s), each beacon using a different channel (91 - 9s) for transmitting a respective carrier signal (81 - 83), comprises: receiving (37) a receive signal (13) comprising the carrier signals of the beacons; downconverting (38) the receive signal to obtain a downconverted signal (16); filtering (39) all of said different channels out of the downconverted signal to obtain a filtered signal (18); modulating (40) an OBU response (20) onto the filtered signal to obtain a response signal (21); upconverting (41) the response signal to obtain an upconverted signal (23); and transmitting (42) the upconverted signal (23) to the beacons. An OBU is configured to carry out a DSRC with at least two beacons.