GB/T 20851.5: Evolution and historical versions
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Electronic toll collection -- Dedicated short range communication -- Part 5: Test methods of the main parameters in physical layer
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GB/T 20851.5-2019
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| GB/T 20851.5-2007 | English | 110 |
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[including 2012XG] Electronic toll collection -- Dedicated short range communication -- Part 5: Test methods of the main parameters in physical layer
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Basic data | Standard ID | GB/T 20851.5-2019 (GB/T20851.5-2019) | | Description (Translated English) | Electronic toll collection -- Dedicated short range communication -- Part 5: Test methods of the main parameters in physical layer | | Sector / Industry | National Standard (Recommended) | | Classification of Chinese Standard | L79 | | Classification of International Standard | 35.100.10 | | Word Count Estimation | 26,239 | | Date of Issue | 2019-05-10 | | Date of Implementation | 2019-12-01 | | Older Standard (superseded by this standard) | GB/T 20851.5-2007 | | Quoted Standard | GB/T 9254; GB/T 12190-2006; GB/T 20851.1-2019 | | Issuing agency(ies) | State Administration for Market Regulation, China National Standardization Administration | | Summary | This standard specifies the recommended characteristics, test conditions and test methods of the main test equipment and accessories for the main parameters of the short-range communication physical layer for electronic charging. This standard is applicable to electronic toll collection systems for highways and urban roads, and can be used for reference in the fields of automatic vehicle identification and vehicle exit management. | GB/T 20851.5-2019: Electronic toll collection -- Dedicated short range communication -- Part 5: Test methods of the main parameters in physical layer
---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.
e) Gain. Available.
5 Test conditions
5.1 Test site and configuration
5.1.1 Test site
Radiation testing can be performed in an anechoic chamber or in an open field.
The minimum size of the anechoic chamber should meet the requirements of the 3m test, and the shielding effectiveness should meet the requirements of GB/T 12190-2006.
The attenuation of chemical sites shall meet the requirements of GB/T 9254.
When testing in an anechoic chamber, the equipment under test should be within the quiet zone of the darkroom.
The normalized attenuation of the open field shall meet the requirements of GB/T 9254.
5.1.2 Configuration
5.1.2.1 Conduction test system configuration
The conduction test system consists of the device under test, test equipment, and connection accessories. The connection accessories include connectors, attenuators, and so on. Connecting accessories
Determined according to the interface of the device under test and the strength of the signal under test. The block diagram of the conduction test system configuration is shown in Figure 1.
Figure 1 Block diagram of the conduction test system configuration
5.1.2.2 Radiation test system configuration
The radiation test system consists of the device under test, test equipment, and connection accessories.The connection accessories include coaxial cables, test antennas, connectors,
Attenuators, etc. The connection accessories are determined according to the interface of the device under test and the strength of the signal under test. The block diagram of the radiation test system configuration is shown in Figure 2.
Figure 2 Block diagram of radiation test system configuration
The distance d between the device under test and the test antenna should satisfy equation (1).
d≥
2D2
(1)
The height h of the device under test and the test antenna from the ground should satisfy equation (2).
h≥4D (2)
5.2 Test signal
The test system shall provide the following test signals.
a) Bit rate test signal, modulate all zero codes of FM0 code at working frequency;
b) Co-channel and adjacent-channel interference rejection ratio interference test signals, the modulated uncoded pseudo-random binary with a period of 511 bits
Sequence (PN9) signal;
c) Blocking interference suppression ratio interference test signal, working frequency band (5725MHz ~ 5850MHz) out of band (30MHz ~ 20GHz)
A fixed-frequency continuous wave signal;
d) The OBU wake-up response signal transmits the carrier signal on the corresponding channel for a duration of 20ms.
5.3 Test status requirements of the DUT
5.3.1 RSU
The RSU under test shall be able to receive and transmit test signals in accordance with the requirements of 5.2 and the test needs. That is, it can continuously transmit carriers and modulate
The working frequency point's PN9 code and FM0 coded all-zero code can lead to demodulated received data and clock signals, and provide test points.
5.3.2 OBU
The OBU under test shall be able to receive and transmit test signals in accordance with the requirements of 5.2 and the test needs. That is, it can transmit the carrier wave and modulate the work.
The PN9 code at the frequency point and the all-zero code of the FM0 code are transmitted after the wake-up signal. Can lead to demodulated received data in time
Clock signal and provide test points.
5.3.3 OBU Initialization Device
The OBU initialization device under test shall be able to receive and transmit test signals in accordance with the requirements of 5.2 and the test needs. That is, it can transmit carrier waves and modulate
The working frequency point's PN9 code and FM0 coded all-zero code can lead to demodulated received data and clock signals, and provide test points.
6 Test method
6.1 General
Projects that have the ability to conduct conduction tests during the test should be tested using conduction testing methods.
6.2 RSU test
6.2.1 Carrier frequency and frequency tolerance
6.2.1.1 Test equipment
The carrier frequency and frequency tolerance test equipment is a frequency meter or a spectrum analyzer with a counter.
6.2.1.2 Test procedure
This test can be done under conducted or radiated test conditions.The test steps are as follows.
a) Set the working frequency of the DUT transmitter, and set the DUT to work in a non-modulated state, that is, the carrier state;
b) use a frequency meter or a spectrum analyzer with a counter to measure the actual carrier frequency fTxa of the device under test;
c) Calculate the frequency tolerance Δf of the carrier frequency according to formula (3).
Δf =
| fTx-fTxa |
fTx × 106
(3)
d) Repeat the above steps to test other carrier frequencies and their frequency tolerances.
6.2.2 Occupied Bandwidth
6.2.2.1 Test equipment
The occupied bandwidth test equipment is a spectrum analyzer.
6.2.2.2 Test procedure
This test can be done under conducted or radiated test conditions.The test steps are as follows.
a) Set the working frequency of the DUT transmitter, and set the DUT to continuously transmit test signals;
b) Set the transmit power of the device under test to the maximum value;
c) measuring the occupied bandwidth of the test signal with a spectrum analyzer;
d) Repeat the above steps to measure the occupied bandwidth at other carrier frequencies.
6.2.3 Equivalent radiated power
6.2.3.1 Conduction test
6.2.3.1.1 Test equipment
The equivalent isotropic radiated power conduction test equipment is a power meter.
6.2.3.1.2 Test procedure
The test steps are as follows.
a) Set the working frequency of the DUT transmitter, and set the DUT to the non-modulated state, that is, the carrier state;
b) Set the transmit power of the device under test to the maximum value;
c) Use a power meter to measure the power Pcw of the antenna port of the device under test, and calculate the maximum equivalent isotropic radiated power ei according to formula (4).
r.pmax.
eirpmax = Pcw × GTx (4)
d) Repeat the above steps to test the equivalent isotropic radiated power at other carrier frequencies.
6.2.3.2 Radiation test
6.2.3.2.1 Test equipment
Equivalent omnidirectional radiation power radiation testing equipment includes power meters and microwave signal sources.
6.2.3.2.2 Test procedure
The test steps are as follows.
a) according to 6.2.3.1.2 a);
b) according to 6.2.3.1.2 b);
c) Measure power Pcw with a power meter;
d) Under the same test conditions, replace the device under test with a microwave signal source and a test antenna of known gain GT, and use a power meter to measure
Measure power Pcwo, adjust the output power P0 of the microwave signal source until Pcwo is equal to Pcw;
e) Calculate the maximum equivalent isotropic radiated power eirpmax according to formula (5).
eirpmax = P0 × GT (5)
f) Follow 6.2.3.1.2d).
6.2.4 Spurious emissions
6.2.4.1 Conduction test
6.2.4.1.1 Test equipment
The spurious emission conduction test equipment is a spectrum analyzer.
6.2.4.1.2 Test steps
The meter measures the power and adjusts the output power Po of each frequency band of the microwave signal source until the power measured by the spectrum analyzer is equal to Pcon;
f) Calculate the spurious equivalent isotropic radiated power eirpcon of the corresponding frequency band according to formula (7).
eirpcon = Po × GT (7)
g) Repeat the above steps to test spurious emissions in various frequency bands at other carrier frequencies.
6.2.5 Modulation mode and modulation coefficient
6.2.5.1 Test equipment
The modulation mode and modulation coefficient testing equipment is a vector signal analyzer.
6.2.5.2 Test procedure
This test can be done under conducted or radiated test conditions. The test steps are as follows.
a) Set the working frequency of the DUT transmitter, and set the DUT to continuously transmit test signals;
b) Set the transmit power of the device under test to the maximum value;
c) Set the modulation coefficient of the device under test to its minimum value within the allowable range;
d) use a vector signal analyzer to measure the modulation coefficient of the device under test;
e) Change the working frequency of the transmitter of the device under test, leaving the other settings unchanged, and test the modulation coefficients at other carrier frequencies;
f) Set the modulation coefficient of the device under test to its maximum value within the allowable range;
g) measuring the modulation coefficient of the device under test with a vector signal analyzer;
h) Change the working frequency of the transmitter of the device under test, leaving the other settings unchanged, and test the modulation coefficients at other carrier frequencies.
6.2.6 Bit rate
6.2.6.1 Test equipment
The bit rate test equipment is a digital oscilloscope.
6.2.6.2 Test procedure
This test can be done under conducted or radiated test conditions. The test steps are as follows.
a) Set the working frequency of the DUT transmitter, and set the DUT to continuously transmit test signals;
b) Set the transmit power of the device under test to the maximum value;
c) Set the modulation coefficient of the device under test to its maximum value within the allowable range;
d) measure the bit rate with a digital oscilloscope;
e) Repeat the above steps to measure the bit rate at other carrier frequencies.
6.2.7 Receiving sensitivity
6.2.7.1 Conduction test
6.2.7.1.1 Test equipment
The receiving sensitivity conduction test equipment includes a vector signal source and a bit error meter.
6.2.7.1.2 Test steps
The test steps are as follows.
a) Set the working frequency of the receiver of the device under test, and set the device under test to the normal working state;
b) Use a vector signal source to send a test signal of the center frequency of the working channel of the device under test to the receiver of the device under test through the test cable
Incoming terminal and bit error meter;
c) Connect the demodulated data signal and clock signal output from the receiver of the device under test to the bit error meter to measure the error
Bit rate;
d) Adjust the power P0 of the test signal sent by the vector signal source until the bit error rate of the receiver under test reaches the limit required by the standard;
e) Calculate the receiving sensitivity SRx of the device under test on this working channel according to formula (8).
SRx =
P0
GRx
(8)
f) Repeat the above steps to test the receiving sensitivity of other working channels.
6.2.7.2 Radiation test
6.2.7.2.1 Test equipment
The receiving sensitivity radiation test equipment includes a vector signal source, a bit error meter, and a spectrum analyzer.
6.2.7.2.2 Test steps
The test steps are as follows.
a) according to 6.2.7.1.2 a);
b) Use a vector signal source to send a test signal of the center frequency of the working channel of the device under test to the receiver of the device under test through the test antenna.
Incoming terminal and bit error meter;
c) according to 6.2.7.1.2c);
d) according to 6.2.7.1.2d);
e) Under the same test conditions, replace the device under test with a test antenna of known gain GT, and measure the test day with a spectrum analyzer
Power of the line received signal PR;
f) Calculate the receiving sensitivity SRx of the device under test on this working channel according to formula (9).
SRx =
PR
GT
(9)
g) Follow 6.2.7.1.2f).
6.2.8 Receive Bandwidth
6.2.8.1 Conduction test
6.2.8.1.1 Test equipment
The receiving bandwidth conduction test equipment includes a vector signal source and a bit error meter.
6.2.8.1.2 Test steps
The test steps are as follows.
a) Set the working frequency of the receiver of the device under test, and set the device under test to the normal working state;
b) Use a vector signal source to send a test signal of the center frequency of the working channel of the device under test to the receiver of the device under test through the test cable
Incoming terminal and bit error meter;
c) The data signal and clock signal demodulated by the receiver of the device under test are connected to the BER tester, and the receiving spirit of the receiver of the device under test is measured.
Sensitivity
d) Set the test signal power P0 to be 6dB higher than the receiver sensitivity of the DUT;
e) Reduce the frequency of the signal sent by the vector signal source until the bit error rate of the receiver under test reaches but does not exceed the limit required by the standard; record
The lower limit frequency of the receiving bandwidth is f1. The signal frequency of the vector signal source is increased until the bit error rate of the receiver under test reaches but
Exceeds the limit required by the standard; records the upper limit frequency of the receiving bandwidth as f2;
f) the receiving bandwidth of the device under test is f1 ~ f2;
g) Repeat the above steps to test the receiving bandwidth of other working channels.
6.2.8.2 Radiation test
6.2.8.2.1 Test equipment
The receiving bandwidth radiation test equipment includes a vector signal source and a bit error meter.
6.2.8.2.2 Test procedure
The test steps are as follows.
a) according to 6.2.8.1.2a);
b) Use a vector signal source to send a test signal of the center frequency of the working channel of the device under test to the receiver of the device under test through the test antenna.
Incoming terminal and bit error meter;
c) according to 6.2.8.1.2c);
d) according to 6.2.8.1.2d);
e) according to 6.2.8.1.2e);
f) according to 6.2.8.1.2f);
g) Follow 6.2.8.1.2g).
6.2.9 Maximum input signal power
6.2.9.1 Conduction test
6.2.9.1.1 Test equipment
The highest input signal power transmission test equipment includes vector signal sources and bit error meters.
6.2.9.1.2 Test procedure
The test steps are as follows.
a) Set the working frequency of the receiver of the device under test, and set the device under test to the normal working state;
b) Use a vector signal source to send a test signal of the center frequency of the working channel of the device under test to the receiver of the device under test through the test cable
Incoming terminal and bit error meter;
c) The data signal and clock signal demodulated by the receiver of the device under test are connected to the bit error meter to measure the bit error rate of the receiver of the device under test;
d) Adjust and increase the power P0 of the test signal sent by the vector signal source until the bit error rate of the receiver under test reaches but does not exceed the standard requirement.
Required limits;
e) Calculate the highest allowable input signal power of the device under test when the receiving bit error rate of the working channel meets the standard requirements according to formula (10).
Rate Pi, max.
Pi, max =
P0
GRx
(10)
f) Repeat the above steps to test the highest input signal power of other working channels.
6.2.9.2 Radiation test
6.2.9.2.1 Test equipment
The highest input signal power radiation test equipment includes vector signal sources, bit error meters, and spectrum analyzers.
6.2.9.2.2 Test steps
The test steps are as follows.
a) according to 6.2.9.1.2 a);
b) Use a vector signal source to send a test signal of the center frequency of the working channel of the device under test through the test antenna to the receiver of the device under test
And bit error meters;
c) according to 6.2.9.1.2c);
d) according to 6.2.9.1.2d);
e) Under the same test conditions, replace the device under test with a spectrum analyzer and a test antenna of known gain GT, and use spectrum analysis
Meter to measure power PR;
f) Calculate the maximum allowable input signal power of the device under test when the receiving bit error rate of the working channel meets the standard requirements according to formula (11).
Rate Pi, max.
Pi, max =
PR
GT
(11)
g) Follow 6.2.9.1.2f).
6.2.10 Co-channel interference rejection ratio
6.2.10.1 Conduction test
6.2.10.1.1 Test equipment
The co-channel interference suppression ratio conduction test equipment includes a vector signal source and a bit error meter.
6.2.10.1.2 Test procedure
The test steps are as follows.
a) Set the working frequency of the receiver of the device under test, and set the device under test to the normal working state;
b) Use a vector signal source to send a test signal of the center frequency of the working channel of the device under test to the receiver of the device under test through the test cable
Incoming terminal and bit error meter;
c) The data signal and clock signal demodulated by the receiver of the device under test are connected to the BER tester, and the receiving spirit of the receiver of the device under test is measured.
Sensitivity
d) Use two vector signal sources to send the test signal of the center frequency of the working channel of the device under test and the interference test signal to the device under test
Receiver input;
e) Set the test signal power P0 to be 6dB higher than the receiving sensitivity of the DUT receiver;
f) Adjust the power of the vector signal source to send the interference test signal PC until the bit error rate of the receiver under test reaches but does not exceed the standard requirement.
Required limits;
g) Calculate the co-channel interference suppression ratio RC of the device under test on the working channel according to formula (12).
RC =
P0
PC
(12)
h) Repeat the above steps to test the co-channel interference suppression ratio of other working channels.
6.2.10.2 Radiation test
6.2.10.2.1 Test equipment
The co-channel interference suppression ratio radiation test equipment includes a vector signal source and a bit error meter.
6.2.10.2.2 Test procedure
The test steps are as follows.
a) according to 6.2.10.1.2a);
b) Use a vector signal source to send a test signal of the center frequency of the working channel of the device under test to the receiver of the device under test through the test antenna.
And bit error meters;
c) according to 6.2.10.1.2c);
d) according to 6.2.10.1.2d);
e) according to 6.2.10.1.2e);
f) 6.2.10.1.2f);
g) according to 6.2.10.1.2g);
h) Follow 6.2.10.1.2h).
6.2.11 Adjacent channel interference suppression ratio
6.2.11.1 Conduction test
6.2.11.1.1 Test equipment
Adjacent channel interference suppression ratio conduction test equipment includes vector signal sources and bit error meters.
6.2.11.1.2 Test procedure
The test steps are as follows.
a) Set the working frequency of the receiver of the device under test, and set the device under test to the normal working state;
b) Use a vector signal source to send a test signal of the center frequency of the working channel of the device under test to the receiver of the device under test through the test cable
Incoming terminal and bit error meter;
c) The data signal and clock signal demodulated by the receiver of the device under test are connected to the BER tester, and the receiving spirit of the receiver of the device under test is measured.
Sensitivity
d) Use two vector signal sources to send the test signal of the center frequency of the working channel of the device under test and the center frequency of the adjacent working channel.
Interference test signal to the receiver input of the device under test;
e) Set the test signal power P0 to be 6dB higher than the receiving sensitivity of the DUT receiver;
f) Adjust the power PA of the vector signal source to send the interference test signal until the bit error rate of the receiver under test reaches but does not exceed the standard
Required limits;
g) Calculate the adjacent channel interference suppression ratio RA of the device under test on this working channel according to formula (13).
RA =
P0
PA
(13)
h) Repeat the above steps to test the adjacent channel interference suppression ratio of other working channels.
6.2.11.2 Radiation test
6.2.11.2.1 Test equipment
Adjacent channel interference suppression ratio radiation test equipment includes vector signal sources and bit error meters.
6.2.11.2.2 Test procedure
The test steps are as follows.
a) according to 6.2.11.1.2a);
b) Use a vector signal source to send a test signal of the center frequency of the working channel of the device under test to the receiver of the device under test through the test antenna.
And bit error meters;
c) according to 6.2.11.1.2c);
d) according to 6.2.11.1.2d);
e) according to 6.2.11.1.2e);
f) according to 6.2.11.1.2f);
g) according to 6.2.11.1.2g);
h) Follow 6.2.11.1.2h).
6.2.12 Blocking interference rejection ratio
6.2.12.1 Conduction test
6.2.12.1.1 Test equipment
The block interference suppression ratio conduction test equipment includes a vector signal source and a bit error meter.
6.2.12.1.2 Test procedure
The test steps are as follows.
a) Set the working frequency of the receiver of the device under test, and set the device under test to the normal working state;
b) Use a vector signal source to send a test signal of the center frequency of the working channel of the device under test to the receiver of the device under test through the test cable
Incoming terminal and bit error meter;
c) The data signal and clock signal demodulated by the receiver of the device under test are connected to the BER tester, and the receiving spirit of the receiver of the device under test is measured.
Sensitivity
d) Use two vector signal sources to send the test signal of the center frequency of the working channel of the device under test, and the blocking interference outside the working frequency band.
Disturb the test signal to the receiver input of the device under test;
e) Set the test signal power P0 to be 6dB higher than the receiving sensitivity of the DUT receiver;
f) Adjust the power PB of the vector signal source to send the blocking interference test signal until the bit error rate of the receiver under test reaches but does not exceed the standard
Standard required limits;
g) Calculate the blocking interference suppression ratio RB of the device under test in this working channel according to formula (14).
RB =
P0
PB
(14)
h) Repeat the above steps to test the blocking interference suppression ratio of other working channels.
6.2.12.2 Radiation test
6.2.12.2.1 Test equipment
The blocking interference suppression ratio radiation test equipment includes a vector signal source and a bit error meter.
6.2.12.2.2 Test procedure
The test steps are as follows.
a) according to 6.2.12.1.2a);
b) Use a vector signal source to send a test signal of the center frequency of the working channel of the device under test to the receiver of the device under test through the test antenna.
And bit error meters;
c) according to 6.2.12.1.2c);
d) according to 6.2.12.1.2d);
e) according to 6.2.12.1.2e);
f) 6.2.12.1.2f);
g) according to 6.2.12.1.2g);
h) Follow 6.2.12.1.2h).
6.3 OBU test
6.3.1 Carrier frequency and frequency tolerance
The test methods for OBU carrier frequency and frequency tolerance are performed in accordance with 6.2.1.
6.3.2 Occupied Bandwidth
The test method for OBU occupied bandwidth is performed according to 6.2.2.
6.3.3 Equivalent radiated power
The relevant test methods for OBU equivalent omnidirectional radiated power are carried out in accordance with 6.2.3.
6.3.4 Spurious emissions
The test methods related to OBU spurious emissions are carried out in accordance with 6.2.4.
6.3.5 Modulation method and modulation coefficient
The OBU modulation mode and modulation coefficient related test method are carried out according to 6.2.5.
6.3.6 Bit rate
The test method for OBU bit rate is performed according to 6.2.6.
6.3.7 Wake Sensitivity
6.3.7.1 Conduction test
6.3.7.1.1 Test equipment
The wake-up sensitivity conduction test equipment is a vector signal source.
6.3.7.1.2 Test procedure
The test steps are as follows.
a) Set the working frequency of the receiver of the device under test, and set the device under test to the normal working state;
b) use the vector signal source to send the wake-up signal of the center frequency of the working channel of the device under test to the receiver input of the device under test;
c) Adjust the power P0 of the vector signal source to send the test wakeup signal until the device under test is woken up;
d) Calculate the wake-up sensitivity SW of the device under test in this working channel according to formula (15).
SW =
P0
GRx
(15)
e) Repeat the above steps to test the wake-up sensitivity of other working channels.
6.3.7.2 Radiation test
6.3.7.2.1 Test equipment
Wake sensitivity radiation test equipment includes vector signal sources and spectrum analyzers.
6.3.7.2.2 Test procedure
The test steps are as follows.
a) according to 6.3.7.1.2 a);
b) according to 6.3.7.1.2 b);
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