GB/T 20851.5-2019Electronic toll collection - Dedicated short range communication - Part 5: Test methods of the main parameters in physical layer (English PDF)

Foreword

GB/T 20851.5-2019 was issued on 10 May 2019 by the State Administration for Market Regulation and the Standardization Administration of the People's Republic of China, and came into force on 1 December 2019. It is classified under ICS 35.100.10 and Chinese Standard Classification code L 79. It replaces GB/T 20851.5-2007.

GB/T 20851, Electronic toll collection - Dedicated short range communication, is divided into five parts: Part 1: Physical layer; Part 2: Data link layer; Part 3: Application layer; Part 4: Equipment application; Part 5: Test methods of the main parameters in physical layer. This document is Part 5 of GB/T 20851.

This part was drafted in accordance with the rules given in GB/T 1.1-2009.

This part replaces GB/T 20851.5-2007, Electronic toll collection - Dedicated short range communication - Part 5: Test methods of the main parameters in physical layer. Apart from editorial changes, the main technical changes with respect to GB/T 20851.5-2007 are as follows: the requirements for the test signals have been revised and extended (see 5.2, and 5.2 of the 2007 edition); a subclause on the required test state of the equipment under test has been added (see 5.3); the way the test methods are expressed has been revised (see 6.2, 6.3 and 6.4, and 6.2, 6.3, 6.4, 6.5, 6.6, 6.7 and 6.8 of the 2007 edition); test methods have been added for the receive sensitivity, receive bandwidth, highest input signal power, co-channel interference rejection ratio, adjacent-channel interference rejection ratio and blocking interference rejection ratio of the roadside unit (see 6.2); test methods have been added for the wake-up sensitivity, wake-up time, receive sensitivity, receive bandwidth, highest input signal power, co-channel interference rejection ratio, adjacent-channel interference rejection ratio and blocking interference rejection ratio of the on-board unit (see 6.3); and the test method for the on-board unit initialisation equipment has been revised and extended (see 6.4, and 6.4 of the 2007 edition).

This part was proposed by and is under the jurisdiction of the National Technical Committee on Intelligent Transport Systems of Standardization Administration of China (SAC/TC 268).

The drafting organisations of this part are: Research Institute of Highway of the Ministry of Transport; Zhongguancun Zhongjiao Guotong Intelligent Transportation Industry Alliance; Beijing Zhongjiao Guotong Intelligent Transportation System Technology Co., Ltd.; Beijing Juli Technology Co., Ltd.; Shanghai Changjiang Intelligent Data Technology Co., Ltd.; and Beijing Sutong Technology Co., Ltd.

The main drafters of this part are: Li Hankui, Xiao Di, Tian Xiaozhuang, Zhang Yujun, Gui Jie, Li Wei, Zhang Beihai, Zhou Bin, Zhang Chunjie, Chen Bingxun, Liu Hongwei and Li Quanfa.

The previous editions of the standard replaced by this part are: GB/T 20851.5-2007.

1 Scope

Free-flow tolling stands or falls on a radio exchange that lasts a fraction of a second. A vehicle crosses the gantry at highway speed, the roadside unit wakes the transponder behind the windscreen, and the two must complete a transaction before the antenna pattern runs out. Everything that governs whether that happens - the transmitted power, the carrier frequency tolerance, the receive sensitivity, the wake-up sensitivity and wake-up time, the receive bandwidth, the highest tolerable input power, and how well the receiver rejects a co-channel, adjacent-channel or blocking interferer - lives in the physical layer. Two devices that both claim to meet the physical layer specification will still fail against each other if each manufacturer measures those quantities its own way, with its own chamber, its own antenna and its own signal. This part of GB/T 20851 removes that freedom. It fixes the recommended characteristics of the instruments, the test site and system configuration, the test signals and the state the equipment under test must be held in, and then the step-by-step measurement procedure for each physical layer parameter of both roadside and on-board units.

This part of GB/T 20851 specifies the recommended characteristics of the main test equipment and accessories, the test conditions and the test methods for the main parameters of the physical layer of dedicated short range communication for electronic toll collection.

This part applies to electronic toll collection systems for highways and urban roads. It may also be used for reference in the fields of automatic vehicle identification, vehicle access management and similar applications.

2 Normative references

The following documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including all amendments) applies.

GB/T 9254, Information technology equipment - Radio disturbance characteristics - Limits and methods of measurement.

GB/T 12190-2006, Measurement method for the shielding effectiveness of electromagnetic shielding enclosures.

GB/T 20851.1-2019, Electronic toll collection - Dedicated short range communication - Part 1: Physical layer.