WO2019205907A1

WO2019205907A1 - Intelligent device communication platform based on mqtt message protocol

Info

Publication number: WO2019205907A1
Application number: PCT/CN2019/081226
Authority: WO
Inventors: 易子川; 刘黎明; 张智; 迟锋; 杨健君; 水玲玲
Original assignee: 电子科技大学中山学院
Priority date: 2018-04-27
Filing date: 2019-04-03
Publication date: 2019-10-31
Also published as: CN108810086A

Abstract

Disclosed is an intelligent device communication platform based on an MQTT message protocol. The platform comprises a client and a server, wherein the client establishes wireless communication with the server by means of a publishing/subscription mode message protocol of an MQTT binary message; the client comprises an address publishing module, an identifier subscription module, a data publishing module and an information subscription module; and the server comprises an address subscription module, an identifier publishing module, an information publishing module and a data subscription module. The client and the server establish connection and communication by means of a publishing/subscription mode, thus providing an MQTT protocol communication platform for intelligent devices and mobile devices, such as low-power-consumption sensors, mobile phones, embedded computers and micro-controllers. By using the concise performance of an MQTT message protocol, where the communication platform has a high scalability, the energy and traffic losses of an access device are reduced, and communication services with high S/N and reliability can be provided for terminal devices faced with poor transmission conditions, such as a limited computing capability and a low working frequency band.

Description

A smart device communication platform based on MQTT message protocol

Technical field

The invention relates to a digital information transmission platform, in particular to a smart device communication platform based on the MQTT message protocol.

Background technique

With the continuous development of the Internet, the application of the message protocol is constantly maturing. The main method for the Internet to obtain messages is the PULL and PUSH modes. The pull mode refers to the way the client requests messages from the server. Push mode refers to the way the server sends messages to the client actively. The push mode is more common in the mobile terminal. Because the mobile port has real-time characteristics, the push mode will give users a more friendly experience. After years of research and application, and emerging Under the rapid development of Internet of Things, mobile communication and smart device communication, XMPP and MQTT have gradually become the two mainstream of message protocols. Among them, XMPP (Extensible Message Processing Field Protocol) is an improved protocol by XML protocol. It is used in many real-time communication software on mobile terminals. Its advantages are perfect protocol, versatility and multi-extensibility, but its shortcomings are relatively complicated, redundant, energy-consuming and high cost of deploying hardware in a bad communication environment. Under the XMPP protocol, the data transmission will be abnormally weak, the reliability of the transmitted data and the S/N are too low. MQTT (Message Queue Telemetry Transmission) transmits messages by means of publish/subscribe. It is especially suitable for network unstable, low-bandwidth communication scenarios and low-power intelligent control devices to meet lower network bandwidth and device resources. At the same time, to ensure the accuracy of message delivery, therefore, under certain circumstances, MQTT has considerable advantages over XMPP protocol. In view of the rapid development of mobile Internet in China in recent years, messaging technology in medical, education, media and e-commerce, etc. The application of the industry is more and more extensive, and smart devices often face the bad transmission conditions such as limited computing power, low working frequency band and unreliable network. The MQTT publishable/subscribeable messaging mode and open source message proxy software are designed. A communication platform that supports the communication of sensors and control devices has considerable social significance.

Summary of the invention

In order to overcome the deficiencies of the prior art, the present invention provides a smart device communication platform based on the MQTT message protocol, which is suitable for a network unstable and low bandwidth communication scenario and a low resource intelligent control device.

The technical solution adopted by the present invention to solve the technical problem thereof is:

A smart device communication platform based on the MQTT message protocol, comprising a client for data transmission and information reception and a server for information processing and transmission, the client and the server establish wireless with a publish/subscribe mode message protocol of MQTT binary message communication;

The client includes:

Address publishing module: used to store and send a MAC address to the server;

The identifier subscription module is configured to acquire a device ID and an access time allocated and sent by the server;

Data publishing module: used to send client-independent information data to the server;

Information subscription module: used to receive the content of the message sent by the server;

The server includes:

Address subscription module: used to receive and process the MAC address sent by the client;

Identity publishing module: used to generate and send a device ID and access time;

Information publishing module: used to send message content to the client;

Data subscription module: used to receive information data sent by the client.

The client and server architecture configuration includes the following four steps:

Step 1: The client sends the MAC address in the address issuing module to the server.

Step 2: After the address subscription module of the server receives the MAC address, the identity issuing module generates and sends the device ID and the access time to the client, and the message publishing module sends the message content to the client according to the MAC address.

Step 3: After the identity subscription module of the client obtains the device ID and the access time sent by the server, the information subscription module receives the message content sent by the client according to the device ID and the access time.

Step 4: The data publishing module of the client feeds back the client independent information data to the server, and is received by the data subscription module. After the client and server architecture are configured, the client and the server perform a publish/subscribe communication connection.

The message agent software that implements the MQTT protocol by the client and the server is Mosquitto.

The process of issuing the communication connection between the client and the server in the step 4 is as follows:

(1) Initialize the Mosquitto library function, set the publish subscription function, connection server function and various callback functions included in the Mosquitto library function to initial values, and destroy various function functions such as MQTT function;

(2) Establish a new client with the client name saved in the Mosquitto internal mosq structure;

(3) setting a registration function, a connection information, and a callback function for posting information;

(4) The callback function of the connection information is used to keep the client and the server connected, and the module name, the payload part and the service quality of the data release module and the information release module are parameterized and sent to the server and the client respectively;

(5), call the internal source code of the Mosquitto library function, let the client and server maintain a long-term connection, and release the memory space of the Mosquitto instance and clear the resources used by the Moquitto library function.

The terminal system used by the client is Linux.

The connection protection mechanism used by the client and the server is a heartbeat mechanism, and the heartbeat interval is 300 seconds.

The invention has the beneficial effects that the invention is based on the Linux system and the Mosquitto open source project for client build and server programming, and the client and the server establish a connection and communication through a publish/subscribe mode, for low-power sensors, mobile phones, Intelligent devices and mobile devices such as embedded computers and microcontrollers provide the MQTT protocol communication platform, which utilizes the compact performance of the MQTT message protocol to reduce the energy and traffic loss of access devices when the communication platform has high scalability. Terminal equipment with limited computing power and low operating frequency conditions provides high S/N and reliable communication services.

DRAWINGS

The invention will now be further described with reference to the drawings and embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic view of a knotted platform structure of the present invention.

detailed description

Referring to FIG. 1, a smart device communication platform based on the MQTT message protocol includes a client for data transmission and information reception and a server for information processing and transmission, and the client and the server use a publish/subscribe mode of MQTT binary message. The message protocol establishes wireless communication, and the client in the communication platform uses Linux as the terminal system, and the development environment of the Linux terminal system is based on the existing g++, libc6-dev, linux-libc-dev, libstdc++6-4.1- The environment software and the header file library such as dev and Code::Blocks are constructed, and the message agent software for implementing the MQTT protocol by the client and the server is Mosquitto.

The MQTT message format consists of three parts: Fixed Header, Variable Header, and Payload. The header of each MQTT Command message must contain a fixed message. The header is used to describe the packet information, such as the type and level of the packet. The variable header changes according to different types of packets. It does not necessarily exist in the MQTT message. The payload part is the client and the server. The communication content contained therein may include information such as a module name (TopicName) and a client ID (ClientIdentifier) in addition to the communication content.

The connection protection mechanism used by the client and the server is a heartbeat mechanism, and the heartbeat interval is 300 seconds. The client periodically sends a simple heartbeat packet to the server to maintain a long connection between the client and the server, and the heartbeat mechanism in the MQTT. In every heartbeat interval, the client sends a PINGREQ message to the server. After receiving the message, the server will reply the PINGRESP message to the client, complete a heartbeat interaction, and then wait for the next round. The heartbeat message, if the client does not receive the heartbeat response, it will close the TCP/IP port connection, allowing the client to connect with the server for a long time, and can greatly reduce the consumption of the network connection, when the client and the server When the communication is accidentally dropped or does not communicate during the heartbeat period, the will (willingness) protection mechanism is activated. The server will send the pre-defined LWT message to the client of all subscribers instead of the client. This LWT message contains the module. The name and corresponding message content are defined in the variable header.

The client includes:

Address publishing module: used to store and send a MAC address to the server;

The server includes:

Information publishing module: used to send message content to the client;

Data subscription module: used to receive information data sent by the client.

(2) Establish a new client with the client name saved by Mosquitto's internal mosq structure;

The process code for publishing in Mosquitto is as follows:

Mosquitto_lib_init();

Mosq=Mosquitto_new("[USER]PUBLISH",true,&obj);

Mosquitto_log_callback_set(mosq,my_log_callback);

Mosquitto_connect_callback_set(mosq,my_connect_callback);

Mosquitto_publish_callback_set(mosq,my_publish_callback);

Mosquitto_disconnect_callback_set(mosq,my_disconnect_callback);

Mosquitto_message_callback_set(mosq,my_message_callback);

Mosquitto_connect(mosq,host,1883,1);

Mosquitto_publish(mosq,NULL,topic,payloadlen,payload,1,true);

Mosquitto_loop_forever(mosq,-1,1);

Mosquitto_destroy(mosq);

Mosquitto_lib_cleanup();

The process of establishing a communication connection between the client and the server is similar to the process of the above-mentioned publishing mode. The difference is that in the process 4 of the publishing mode, the data publishing module and the information publishing module are replaced with a data subscription module and an information subscription module, and the set parameters are increased. The heartbeat time (keepalive), the subscription process code in Mosquitto is as follows:

Mosquitto_lib_init();

Mosq=Mosquitto_new("[USER]SUBCRIBER1",true,&obj);

Mosquitto_log_callback_set(mosq,my_log_callback);

Mosquitto_connect_callback_set(mosq,my_connect_callback);

Mosquitto_message_callback_set(mosq,my_message_callback);

Mosquitto_subscribe_callback_set(mosq,my_subscribe_callback);

Mosquitto_disconnect_callback_set(mosq,my_disconnect_callback);

If(Mosquitto_connect_async(mosq,host,port,keepalive))

{fprintf(stderr,"Unabletoconnect.\n");return1;}

Mosquitto_subscribe(mosq,&mid,topic,1);

Mosquitto_loop_forever(mosq,-1,1);

Mosquitto_destroy(mosq);

Mosquitto_lib_cleanup();

The invention is based on the Linux system and the Mosquitto open source project for client build and server programming, and the client and the server establish a connection and communication through a publish/subscribe mode for low power sensors, mobile phones, embedded computers, and microcontrollers. Such intelligent devices and mobile devices provide the MQTT protocol communication platform, which utilizes the compact performance of the MQTT message protocol to reduce the energy and flow loss of the access device when the communication platform has high scalability, and can face limited computing power and low working frequency band. Terminal devices such as poor transmission conditions provide high S/N and reliable communication services.

The above embodiments are not intended to limit the scope of the invention, and the modifications and variations made by those skilled in the art without departing from the scope of the present invention are still within the scope of the present invention.

Claims

A smart device communication platform based on the MQTT message protocol, characterized in that it comprises a client for data transmission and information reception and a server for information processing and transmission, and the client and the server use a publish/subscribe mode of MQTT binary message. The message protocol establishes wireless communication;

The client includes:

Address publishing module: used to store and send a MAC address to the server;

The identifier subscription module is configured to acquire a device ID and an access time allocated and sent by the server;

Data publishing module: used to send client-independent information data to the server;

Information subscription module: used to receive the content of the message sent by the server;

The server includes:

Address subscription module: used to receive and process the MAC address sent by the client;

Identity publishing module: used to generate and send a device ID and access time;

Information publishing module: used to send message content to the client;

Data subscription module: used to receive information data sent by the client.
The smart device communication platform based on the MQTT message protocol according to claim 1, wherein the client and server architecture configuration comprises the following four steps:

Step 1: The client sends the MAC address in the address issuing module to the server.

Step 2: After the address subscription module of the server receives the MAC address, the identity issuing module generates and sends the device ID and the access time to the client, and the message publishing module sends the message content to the client according to the MAC address.

Step 3: After the identity subscription module of the client obtains the device ID and the access time sent by the server, the information subscription module receives the message content sent by the client according to the device ID and the access time.

Step 4: The data publishing module of the client feeds back the client independent information data to the server, and is received by the data subscription module. After the client and server architecture are configured, the client and the server perform a publish/subscribe communication connection.
The smart device communication platform based on the MQTT message protocol according to claim 1, wherein the client and the server implement the message broker software of the MQTT protocol as Mosquitto.
The intelligent device communication platform based on the MQTT message protocol according to claim 2 or 3, wherein the process of issuing the communication connection between the client and the server in the step 4 is as follows:

(1) Initialize the Mosquitto library function, set the publish subscription function, connection server function and various callback functions included in the Mosquitto library function to initial values, and destroy various function functions such as MQTT function;

(2) Establish a new client with the client name saved by Mosquitto's internal mosq structure;

(3) setting a registration function, a connection information, and a callback function for posting information;

(4) The callback function of the connection information is used to keep the client and the server connected, and the module name, the payload part and the service quality of the data release module and the information release module are parameterized and sent to the server and the client respectively;

(5), call the internal source code of the Mosquitto library function, let the client and server maintain a long-term connection, and release the memory space of the Mosquitto instance and clear the resources used by the Moquitto library function.
The smart device communication platform based on the MQTT message protocol according to claim 1, wherein the terminal system used by the client is Linux.
The smart device communication platform based on the MQTT message protocol according to claim 1, wherein the connection protection mechanism used by the client and the server is a heartbeat mechanism, and the heartbeat interval is 300 seconds.