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This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard replaces GB/T 20999-2007 Data communication protocol between traffic signal controller and control center. In addition to editorial changes, the following main technical changes have been made with respect to GB/T 20999-2007:
——The terms, such as phase inter green time, phase stage, phase transition constraints and phase stage chain, are added;
——The terms of output channel and clear interval are deleted;
——The content of coordination control is modified as center coordination control and local coordination control;
——Annexes A, B and C specify the communication procedures, status invariants, data tables and data fields;
——Annex D is added for illustration.
This standards was proposed by and is under the jurisdiction of SAC/TC 268 National Technical Committee on Intelligent Transportation Systems of Standardization Administration of China.
The previous edition of this standard is as follows:
——GB/T 20999-2007.
Data communication protocol between traffic signal controller and control center
1 Scope
This standard specifies the requirements for the structure, physical layer, data link layer, network layer and application layer of the data communication protocol between traffic signal controller and control center.
This standard is applicable to the data communication between the signal controller and the control center in the traffic signal control system.
2 Normative references
The following referenced 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 any amendments) applies.
GB/T 15126-2008 Information technology - Open system interconnection - Network service definition
GB/T 17547-1998 Information technology - Open system interconnection - Data link service definition
RFC0768 User datagram protocol
RFC0791 Internet protocol
RFC0793 Transmission control protocol
IEEE 802.2/3: 1985 Ethernet LAN Protocol
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
control center
upper-end device that communicates with, controls and monitors multiple signal controllers in a traffic signal control system
3.2
road traffic signal controller
device that can change the sequence of road traffic signals, adjust the timing and control the operation of road traffic signal lights, which can be referred to as signal controller
3.3
phase
signal sequence consisting of red-yellow-green changes or red-green changes assigned to one or more traffic streams (there is no yellow light for pedestrian light groups)
3.4
offset
difference between the start times or end times of the specified reference intersection and coordinated intersection phases in coordinated control
3.5
signal light group
complete combination of red-yellow-green traffic light for vehicles or red-green traffic light for pedestrians, which corresponds to the output of one phase
3.6
green conflict
specifying that the green signal lights not allowing release at the same time and the green signal lights allowing release at the same time are lit at the same time
3.7
phase inter green time
inter green time between the loss of right-of-way of the previous phase and the gain of right-of-way of the next phase during the signal cycle
3.8
phase stage
status that one or more phases gain the right-of-way at the same time during the signal cycle
3.9
phase transition constraints
constraint rules for phase stage transition
3.10
phase stage chain
sequence of occurrences of a group of phase stage during the signal cycle
3.11
control plan
ordered set of phase setting, stage chain setting and signal timing at intersections
3.12
time table
parameter set in a signal controller indicating the timeslot division and timeslot adoption control mode in a day
3.13
date schedule
table indicating the correspondence between special days (including Sunday) and the used time table in a signal controller
3.14
local control
autonomous control mode of signal controller at local intersection
3.15
center control
mode by which the control center sends commands to the signal controller to control the operation of the signal controller
4 Data communication protocol structure
See Figure 1 for the block diagram of communication protocol structure. The structure includes physical layer, data link layer, network layer and application layer. Each layer, except for application layer, provides various options, and protocols conforming to this standard implement at least one compatible protocol stack from top to bottom. The connection lines in Figure 1 represent the compatibility relationship between connected protocols.
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Data communication protocol structure
5 Physical layer
6 Data link layer
7 Network layer
8 Application layer
Annex A (Normative) Communication frame structure and specification definition
Annex B (Normative) Definition of object identification number
Annex C (Normative) Detailed definitions of data classes
Annex D (Normative) Communication protocols and message examples
Bibliography
