This is the 28th day of my participation in the Challenge. For details, see:More article challenges

Chapter one: Internet of Things and its architecture

1.1 Definition of Internet of Things

Internet of Things (iot) refers to an intelligent network in which objects arrive at a designated data processing center through a transmission network through an intelligent sensing device to realize information interaction and processing between people, objects and objects, and people and objects.

There are three levels:

  1. Sensor Networks: RFID, bar code, sensors…
  2. Information transmission network: long-distance transmission of a large amount of data and information collected by the sensor network
  3. Information application network: intelligent data processing and information services

**1.2 Features of the Internet of Things

  • Full awareness of the Internet of Things
  • Reliable delivery of the Internet of Things
  • Intelligent control of the Internet of Things
  • Multiple data fusion in the Internet of Things

Comprehensive perception, reliable transmission and intelligent control are the basic characteristics of the Internet of Things

**1.3 Concepts related to the Internet of Things

1.3.1 Internet of Things vs Internet

1.3.2 Internet of Things vs Sensor network

  • Sensor network: a network composed of sensor modules and networking modules. The sensor only perceives the signal and does not emphasize the identification of the object. For example, a temperature sensor can sense the temperature of a forest without necessarily identifying that tree

  • Internet of Things: larger than sensor networks. Because we need not only perceptive objects, but also markers. The temperature sensor not only detects the temperature of the forest, but also identifies which trees it is.

1.3.3 Internet of Things vs Ubiquitous Internet

  • “Ubiquitous network” : that is, the widespread network, it is omnipresent, all-inclusive, omnipotent as the basic characteristics, in order to achieve any time, any place, anyone, anything can communicate smoothly as the goal
  • Internet of Things: The starting point and focus of the concept are not completely consistent with the ubiquitous network, but its goal is to break through the mode of person-to-person communication and establish the communication between objects and objects and between objects and people.

1.4 Architecture of the Internet of Things

  • Perception layer
  • The network layer
  • The application layer

1.5 Functions and key technologies of the perception layer

1.5.1 Functions of the Awareness Layer

Complete information collection and signal processing

1.5.2 Key technologies of the Sensing Layer

  • RFID technology: Radio frequency identification technology, also known as electronic tags

A communication technology in which a specific target can be identified by radio signals and related data can be read and written without establishing mechanical or optical contact between the identification system and the specific target

  • ** Sensor technology: ** refers to the device or device that can feel the specified measured part and convert it into usable output signal according to certain rules
  • Embedded system: A device or system in which embedded technology performs specialized functions and is controlled by an internal computer
  • ** Microelectromechanical system (MEMS) : ** Can be manufactured in batches, the collection of micro mechanism, micro sensors, micro actuators and signal processing and control circuits, up to the interface, communication and power supply equal to one micro device or system
  • **GPS technology: ** Global Positioning System
  • **GIS technology: ** Geographic Information system. Real-time global spatial analysis technology based on surveying and mapping, using database as data source for data storage and use, and using computer programming as platform

1.6 Network Layer functions and key Technologies

1.6.1 Network Layer functions

Directly access and transmit the information from the perception layer through the existing Internet, mobile communication network, satellite communication network and other basic network facilities

1.6.2 Key network layer technologies

  • The Internet
  • Mobile network
  • Short range wireless communication technology

1.7 Application Layer functions and key Technologies

1.7.1 Application Layer Functions

According to the needs of users, it can face the management platform and operation platform of practical applications in various industries, and integrate related content services according to the characteristics of various applications.

1.7.2 Key application Layer technologies

  • Cloud computing
  • ** Middleware: ** a class of computer software that connects software components and applications. It includes a set of services so that multiple pieces of software running on one or more machines can interact over a network. A server that provides messaging, passing messages from one object to another.
  • Artificial intelligence (ai)
  • Data mining

Chapter two: Internet of Things awareness technology

2.1 Common automatic identification technologies

2.1.1 Basic concepts of automatic identification technology

  • Basic concepts of identification:

People recognize and understand the characteristics and information of things is a kind of recognition

  • Automatic identification of meaning

Automatic identification technology: it refers to the technology of obtaining identification information or characteristic information contained in the identified object by non-manual means, and realizing real-time data input into a computer or other microprocessor controlled devices without using a keyboard.

  • Automatic identification technology classification
  1. Data acquisition techniques (definition identification)
  2. Feature Extraction technology (Pattern recognition)
  • General principles of automatic identification technology

Identified information –> Obtain information –> Information processing –> Identify information –> Identified information

2.1.2 Automatic barcode identification technology

  • Code of barcode

  • Structure of bar code

    • Left and right side blank area
    • The starting character
    • The data character
    • Check character
    • Termination of the characters

  • Bar code type

    • A dimensional barcode
    • Two dimensional barcode

2.1.3 Radio frequency automatic identification technology

  • RFID System composition

    • Radio tags
    • Rfid read/write device (reader)
    • Application software

  • The basic working principle of RFID system

    The reader emits radio wave energy of specific frequency. When the RADIO frequency tag enters the induced magnetic field, the radio frequency signal sent by the receiver sends out the product information in the memory chip with the energy obtained by the induced current

2.1.4 Automatic card identification technology

  • classification

  • Magnetic card technology

    Magnetic card is the use of magnetic carrier to record information, magnetic card technology applied the basic principles of physics and magnetism

  • IC card technology

    • The principle of

    A microelectronic chip embedded in the ISO 7816 standard card base, in the form of a card, take advantage of the memory characteristics of integrated circuits, save, read and modify the information on the chip

    • species

    Contactless IC card

    Contact IC card

  • Fundamentals of magnetic card technology

    The storage of data on the magnetic strip is achieved by changing the magnetism of oxidized particles on the magnetic strip

2.1.5 Automatic biometric identification technology

  • The basic principle of

    The core lies in how to acquire these biometric features, convert them into digital signals, store them in a computer, and use reliable matching algorithms to complete the process of identification and verification of personal identity.

    Biometric collection -> generate biometric image -> extract biometric -> match biometric -> output result

  • The characteristics of

    1. universal
    2. uniqueness
    3. The stability of
    4. non-replicability

2.1.6 Image automatic recognition technology

  • Levels and basic features of digital image processing

    • The image processing
    • Image recognition (analysis)
    • Image understanding

  • Optical character recognition technology

    Optical character recognition technology: the process of analyzing and processing image files to obtain text and layout information

2.2 Sensor Technology

2.2.1 Overview of sensors

  • It is equivalent to the human features
  • Is actually a function block whose function will come fromSignals from the outside worldConverted toElectrical signals

2.2.2 Micro-electromechanical System (MEMS)

A microdevice or system that can be manufactured in batches, incorporating micro-mechanisms, micro-sensors, micro-actuators, signal processing and control circuits, down to interfaces, communications, and power supplies

  • The characteristics of
    • miniaturization
    • The main material is silicon
    • Batch production
    • integrated
    • Interdisciplinary

Chapter three: RFID technology

**3.1 RFID Technology Overview

3.1.1 Features of RFID technology

It is through the magnetic field and electromagnetic wave, the use of radio frequency method for non-contact two-way communication, in order to achieve the purpose of identification and data exchange, can identify high-speed moving objects and simultaneously identify multiple targets

3.1.2 Components of the RFID system

  • Reader

    It is mainly responsible for the two-way communication with the electronic tag and receiving the control instructions from the host system

    Composition:

    • The radio frequency interface
    • Logic control unit
    • The antenna

  • Electronic tags

    An IC chip and a wireless communication antenna are used to communicate with readers.

    When the system works, the reader sends out a query signal. After receiving the query signal, the label will partially rectifying for THE DC power supply for the circuit in the electronic label to work. The other part of the energy signal is modulated by the data information stored in the electronic tag and reflected back to the reader

  • RFID middleware

    Mediation role between the e-tag and the application

  • Application system software

    Collect target information for centralized statistics and processing

Generally, middleware and application software are referred to as application systems

3.1.3 CLASSIFICATION of RFID

  • By power supply mode:
    • Passive RFID products
    • Active RFID products
    • Semi-active RFID products
  • By frequency of use:
    • Low frequency 125 khz125kh_z125khz
    • High frequency 13.56 MHZ13.56 MH_Z13. 56 MHZ
    • Ultra-high frequency 860 MHZ – – 960 mhz860mh_z – 960 mh_z860mhz – – 960 MHZ
    • Microwave 2.45ghz and 5.8ghZ2.45GH_Z and 5.8GH_Z 2.45ghz and 5.8ghz

3.2 RFID Technology Foundation

3.2.1 RFID communication mode

  • Refers to theReaders and tagsThe transmission of information betweenRadio signal, features: ‘ ‘communication distance is very short’

3.2.2 Common CODING and modulation methods of RFID

  • RFID common coding methods

    Reverse non-return to zero coding, Manchester coding, unipolar return to zero coding, differential two-phase coding, Miller coding, deformed Miller coding and differential coding

  • RFID common modulation methods

    RFID mainly uses digital modulation

    • Amplitude keying
    • The frequency shift keying
    • Phase shift keying

3.3 RFID electronic Tags

Electronic tags are data carriers that carry information about goods

3.3.1 One bit electronic label

One – bit System data amount is one – bit, electronic label only ‘ ‘1 and’ ‘0’ two states

3.3.2 Electronic tags containing chips

Electronic label containing chip is an electronic data carrier based on integrated circuit chip. It is the most used electronic label at present

  • composition

    • The antenna

    • Analog front end (RF front end)

      The main circuit isInductively coupledandMicrowave electromagnetic backscatteringTwo ways of working

    • Control circuit

  • classification

    • Has the memory function, but does not contain the microprocessor electronic tag
    • Contains microprocessor electronic tags

3.3.3 Electronic labels with the storage function

  • Data memory ROM, EEPROM or FRAM

  • Address and security logic

    This label has no microprocessor, address and security logic is the heart of the data carrier, through the state machine to control all processes and states

  • The state machine

    A finite state machine is a sequential logic circuit whose output depends on the past input and the current input.

    In general, in addition to the input and output parts, a finite state machine contains a set of registers that have a “memory” function. The function of these registers is to remember the internal state of the finite state machine. They are often called state registers

  • Segmental storage of electronic labels

    When the storage capacity of the electronic label is large, the storage of the electronic label can be divided into multiple storage segments

3.3.4 Electronic tags containing microprocessors

Electronic tags containing microprocessors can be more flexible to support different application requirements and improve the security of the system. Electronic tags containing microprocessors have their own CPU processor and on-chip operating system

3.4 RFID reader

3.4.1 Composition of a Reader

A reader is a device that reads or writes electronic label information. It can read, display, and process data

  • The reader software

    All the behavior of the reader is controlled by the software

  • Hardware of the reader

    The hardware of a reader consists of an antenna, radio frequency module, control module, and interface

  • Control module

    It consists of ASIC components and microprocessors

  • Rf module

    The rf front end is mainly composed of sending circuit and receiving circuit

  • The interface of the reader

    The data exchange between the reader control module and the application software is mainly accomplished through the reader interface

  • The antenna

    A device for transmitting or receiving radio waves

** Chapter 4: Internet of Things communication technology

4.1 the Internet

4.1.1 Composition of the Internet

The Internet is a global network of connected computers that communicate with each other in a common language

  • ** Edge section: ** all hosts connected to the Internet

Communication between programs running on the system at the edge of the network generally falls into two categories:

  • Client server (C/S)

    • C/S: The customer is the requester of the service and the server is the provider of the service
    • B/S: is a special case of C/S mode. The user interface is realized through the WWW browser

    C/S is based on the local area network, B/S is based on the wide area network.

  • Peer to peer (P2P)

    The two hosts communicate without distinguishing between the service requester and the service provider

  • Core parts:

    • At the core of the network is the router. A router is a dedicated computer (but not a mainframe)

    • Router is the key component of packet switching. Its task is to forward the received group, which is the most important function of the core part of the network

    • In a network, the process of sending data from the sender to the receiver is called data exchange. According to different switching modes, data switching can be divided into three types: circuit switching, packet switching, and packet switching

      • Packet switching: YesStore and forward technology

4.1.2 Internet access technology

  • Categories: narrowband access and broadband access

    Broadband refers to the network infrastructure and services that provide 24-hour online access with a transmission rate of 2Mb/s or above

4.1.3 Layered Structure of the Internet

  • Open System Interconnection Basic Reference Model OSI (7-layer Protocol Architecture)

Physical layer, data link layer, network layer, transport layer, session layer, presentation layer, and application layer

  • TCP/IP architecture

Network interface layer, network layer, transport layer, application layer

  • TCP/IP protocol family
    • HTTP: hypertext transfer protocol
    • WWW: Web server
    • TCP: transmission control protocol
    • UDP: user datagram protocol
    • IP: Internet protocol
    • FTP: file transfer protocol

4.1.4 From Internet to Internet of Things

  • The Internet, which connects every personal computer, is personal-specific and virtual.
  • The Internet of Things makes it possible to communicate effectively between people and things and between things. The birth of the Internet of Things truly marks the complete interconnection of our world.

4.2 Mobile Communication

Mobile communication refers to the communication process that one or both parties can carry out while on the move

4.2.1 Features and Classification

  • The characteristics of
    1. User mobility
    2. The conditions of radio wave propagation are complex
    3. Noise and interference are serious
    4. The system and network structure are complex
    5. Limited frequency resources
  • classification
    1. Clustered mobile communication
    2. Public mobile communication system:Regional system for mobile communicationsandCell system mobile communication, cell system mobile communications, also known as cellular mobile communications.
    3. Satellite mobile communication
    4. Cordless phone

4.2.2 Mobile communication network

  • The system composition of mobile communication network

    1. Mobile Service Switching center MSC
    2. The base station BS
    3. Mobile station MS
    4. Relay transmission system
    5. Database: Store information about users

  • Basic technology of mobile communication network

    1. Coverage mode of mobile communication network

      • Regional system
      • Cell system: the whole service area is divided into several cells, and a base station is set up in each cell

      At present, the network structure of public mobile communication system is all cellular network structure, which is called cellular mobile communication system

    2. The basic technology in mobile communication network — user multiple access technology

      • Frequency division multiple access (FDMA) : channel with different frequencies
      • Time division multiple access (TDMA) : Time is divided into periodic frames
      • Air division multiple access: Antenna beams of the same frequency in different directions
      • Code division multiple access (CDMA) : Each is distinguished by a different coding sequence

  • Mobile communications and the Internet of Things

    Mobile communication system generally consists of mobile terminal, transmission network and network management and maintenance.

    • The application of mobile communication terminal in the Internet of things
    • Application of mobile communication terminal network in Internet of Things
    • Application of mobile communication network management Platform in Internet of Things

4.3 Short range wireless communication technology

4.3.1 Short range wireless communication overview

Low power consumption and miniaturization are the users’ strong pursuit for the current wireless communication products, especially convenient products

In general, as long as the two sides of communication transceiver transmit information through radio waves, and the transmission distance is limited in a short range, usually within dozens of meters, it can be called short-distance wireless communication.

Three important features and advantages:

  • Low cost
  • Low power consumption
  • Peer-to-peer communication

Classification:

  • High speed short range wireless communication technology
  • Low speed short range wireless communication technology

4.3.2 Short-range wireless communication and Internet of Things

In wireless sensor networks, short range wireless communication technology stands out because of the need to place a large number of wireless nodes in a very small range

4.4 Wireless Sensor Network

4.4.1 Overview of wireless Sensor networks

Wireless sensor network (WSN) is a task-oriented wireless AD hoc network system composed of a large number of such micro sensor nodes

4.4.2 Wireless Sensor network and Internet of Things

  • Wireless sensor network, as a network system of perception and data acquisition, is an important part of the Internet of Things, and is the “nerve endings” of the Internet of Things.
  • It is through wireless sensor networks that the Internet of Things realizes the perception of the physical world and obtains detailed and accurate environmental data or target information

Chapter five: Short – range wireless communication technology

5.1 bluetooth

5.1.1 Overview of Bluetooth Technology

  1. Features of Bluetooth technology

    Bluetooth is a technical specification for short – range wireless communication

    • Worldwide application: Bluetooth works in the globally unified and open ISM band of 2.4GHZ 2.4GHZ
    • It can transmit voice and data simultaneously
    • Peer connections of temporary rows can be established

    Several Bluetooth devices are connected into a piconet -> The piconets overlap to become scatterers

    • It has good anti-interference ability

    Frequency hopping is adopted to spread the spectrum

    • Has a small volume for integration into a variety of devices
    • Minimal power consumption

    Four working modes:

    • Active Mode
    • Respiratory pattern (Sniff)
    • Hold mode
    • Hibernation mode (Park)

    The Active mode is the normal working state, and the other three are low power modes specified for energy saving

    • Open interface standards
    • Low cost, allowing devices to be integrated with Bluetooth technology only a small increase in cost

  2. Bluetooth System composition

    The key characteristics of Bluetooth are: robustness, low complexity, low power consumption and low cost

    • The wireless part
    • Link control section
    • Link management support
    • Master terminal interface

    There can be up to 7 active slave units in a piconet. In addition, more slave units can be locked to a master unit, and this state is called hibernation state.

    Several piconets with overlapping coverage areas constitute a scattering network structure

  3. Bluetooth protocol architecture

    The purpose of the Bluetooth specification is to enable interoperability between applications that conform to the specification. To do this, the local device and the remote device need to use the same protocol stack

5.1.2 Bluetooth Networking and Routing Mechanism

  1. Bluetooth network topology

    Bluetooth supports point-to-point and point-to-multipoint communication. The basic networking component of Bluetooth is a piconet, which is actually a personal area network

  2. Bluetooth Routing mechanism

    It can switch between piconets or scatter networks, but must disconnect from the current APN each time it switches

5.1.3 Application of Bluetooth technology

  1. Replace the cable

    From its inception, Bluetooth was positioned as a basic transmission technology that combined language and data applications. One of the simplest applications is the point-to-point alternative cable

  2. The Internet bridge

    The Bluetooth standard further defines the concept of a “network access point” that allows a device to access network resources through this network access point.

    Building such a secure and flexible Bluetooth network requires:

    • Bluetooth access point
    • Local Network server
    • Network management software

  3. A temporary network

    There is no fixed routing device, and all nodes in the network can move freely and connect dynamically in any way

* * 5.2 ZigBee

5.2.1 Overview of ZigBee technology

Low – speed wireless connection technology with low complexity, low cost and low power consumption

  1. ZigBee technical features

    • Low power consumption
    • Low cost
    • Low data transmission rate
    • Short time delay
    • Small effective range
    • The large capacity
    • High safety
    • Unlicensed frequency band and flexible working frequency band

  2. Application goals of ZigBee

  3. ZigBee protocol stack

    The ZigBee protocol stack consists of high-level application specifications, application aggregation layer, network layer, data link layer and physical layer

    • The physical layer
    • Data link layer
    • The network layer
    • The application layer
    • Security layer

5.2.2 ZigBee Networking Technology

  1. ZigBee network layer

It provides functions such as network building, IP address assignment, route discovery, and route maintenance for newly added nodes, and supports star network, Mesh network, and tree network

  • Two wireless devices are used:

    Full-function devices and thin provisioning devices

  • Node types (three)

    ZigBee coordination point, ZigBee routing node and ZigBee terminal node

  1. The structure of ZigBee network node

  2. To form a network

    Two topologies: star topology and point – to – point topology

5.2.3 Application of ZigBee

  • The data transmitted by ZigBee over the network falls into three categories:
    • ** Periodic data: ** Such as data transmitted in sensors, the data rate is defined according to different applications
    • ** Intermittent data: ** Data transmitted when controlling a light switch, for example, the data rate is defined by the application or external excitation
    • ** Repetitive low response time data: ** such as wireless mouse data, the data rate is defined according to the allocated time slot
  • The specific application
    • ** in consumer electronics: ** can replace the current infrared remote control
    • ** In the field of Home and Building Automation: ** Smart Home
    • In the medical field
    • In the field of sensor networks
    • Industrial sectors
    • Precision Agriculture
    • Automobile industry
    • Road indication, convenient and safe road

5.2.4 Wireless Sensor network based on ZigBee

  • It is a distributed system composed of sink nodes and a large number of wireless sensor nodes

  • The wireless information exchange between the sink node and sensor node is realized by ZigBee technology

  1. Structure and Principle

    • ZigBee communication transmission module and its working principle

      It consists of ZigBee transmission module and its peripheral devices

    • Wireless sensor node

      It consists of ZigBee communication transmission module, detection circuit and internal timer

    • Sink node

      It is used to receive the data reported by sensor nodes, perform data fusion processing, and transmit the data to the central information processing and control center through public network or private line

    • Central information processing control center

      The central information processing control center consists of three parts: monitoring module, configuration module and database

  2. The working mode of ZigBee wireless sensor network

    The communication between ZigBee assembly node and sensor node is based on the waking-up mode of demand

    • ZigBee communication transmission module initialization process

5.3 WLAN

Computer local area network with wireless channel as transmission medium

5.3.1 WLAN Technical Standards and Features

  • It is a combination of computer network and wireless communication technology
  • The main protocol standard is 802.11 series

  1. 802.11 series protocols

    802.11: Defines the physical layer and media access control specifications

  2. Technical features of WLAN

    It is a complement and extension to the wired network, making the computer on the network mobile.

    WLAN advantages:

    • Convenient installation
    • Using flexible
    • economies
    • extensible

5.3.2 WLAN topology

Common: Infrastructure architecture pattern

5.3.3 WLAN Applications

Widely used in the need to connect to the mobile network and roaming between networks

5.4 IrDA

5.4.2 IrDA protocols

Three mandatory specifications:

  • The physical layer
  • Connection establishment protocol layer
  • Connection management protocol layer

5.4.3 Application of IrDA

Because of the technical characteristics of infrared communication, it is used in all kinds of low cost and close range data communication

5.5 NFC

5.5.1 NFC concept

Near-field communication (NFC) is a short-range, high-frequency wireless communication technology that allows non-contact point-to-point data transmission and exchange between electronic devices

Technical features: Close range, fast response

5.5.2 Technical Principles of NFC

  1. The working principle of
    • NFC developed from non-contact identification and interconnection technology
    • In one-to-one communication, the party that initiates the connection is calledA deviceThe other party is calledThe target device. Both the initiator and the target support both active and passive communication modes
  2. Working mode
    • Card simulation mode
    • Point-to-point mode
    • Card reader mode

5.5.3 APPLICATION of NFC

Can be used as RFID passive tag, used to pay the cost; It can also be used as an RFID reader for data exchange and acquisition

Four basic types:

  • Payment and ticket purchase
  • The electronic ticket
  • Smart media
  • Exchange and transmit data

Chapter 6: Wireless sensor network technology

It is an intelligent network information system which integrates the functions of information collection, information processing and information transmission.

Wireless sensor network (WSN) technology is an important foundation of Internet of Things (iot), which involves microelectronics, network communication and embedded computing

**6.1 Architecture of wireless Sensor networks

6.1.1 Features of WIRELESS sensor networks

Wireless sensor network (WSN) is a task-oriented wireless AD hoc network system

  • Self-organizing characteristic
  • Distributed control
  • Topological dynamics

6.1.2 Key technologies of wireless sensor networks

  1. Mems technology
  2. Wireless communication technology
  3. Hardware and software platforms
    • Hardware platform: enhanced general purpose PERSONAL computers, dedicated sensor nodes, system-on-chip sensor nodes
    • Software platform: It can be an operating system that provides a variety of services, including file management, memory allocation, task scheduling, peripheral drivers, and networking, or it can be a language platform that provides a library of components for programmers

6.1.3 Application fields of WIRELESS sensor networks

  1. The environmental monitoring
  2. The national defense military
  3. Industrial monitoring
  4. Health care
  5. Smart home
  6. Public safety

6.1.4 Network structure of the wireless Sensor network

  1. Wireless Sensor Node structure (4 functional modules)

    • Sensing module
    • Processing module
    • Communication module
    • Power supply module

  2. Wireless sensor network architecture

    It usually consists of a large number of sensor nodes densely deployed in a specified geographic area and one or more data sink nodes located in or near the region

    • Single-hop network structure: Data is directly sent to the sink node
    • Multi-hop network structure: The sensor node sends the data collected to the sink node through one or more intermediate nodes of the network, thus effectively reducing the energy consumption required for communication

  3. Wireless Sensor Network classification:

6.2 Wireless Sensor Network protocols

6.2.1 Protocol stack of WIRELESS Sensor networks

  • The application layer
  • The transport layer
  • The network layer
  • Data link layer
  • The physical layer

6.2.2 MAC protocol for WIRELESS Sensor networks

  1. Main features:

    • Energy efficiency
    • scalability
    • fairness
    • Transmission efficiency

  2. Classification:

    • Competitive MAC protocol: Use the channel on demand

    When a node needs to send data, the channel is used in a competitive manner. If a conflict occurs, the node retransmits the data according to a preset strategy until the data is successfully sent or abandoned

    • Non-competitive MAC protocol: fixed use channel

    The shared channel is divided into a group of sub-channels according to time, frequency or pseudo noise code, and these sub-channels are allocated to each node, so that each node has a special sub-channel for data transmission

    • Hybrid MAC protocol

    The competitive MAC protocol and non-competitive MAC protocol are combined effectively to reduce data conflict between nodes and improve the transmission performance of the network

6.2.3 Routing Protocols for WIRELESS Sensor networks

  1. The characteristics of

    • Energy conservation priority
    • Many-to-one transmission
    • Data-centric
    • Application of the relevant

  2. Function:

    In order to improve the energy efficiency of the network, prolong the life time of the network, and on this basis, improve the transmission performance and service quality of the network

  3. classification

    • Plane routing protocol
    • Layered routing protocol
    • Energy-based routing protocol
    • Multipath-based routing protocol
    • Routing protocol based on mobility
    • Location-based routing protocol
    • Opportunistic routing protocol
    • Data-centric routing protocol

6.2.4 Wireless Sensor network transmission protocol

A network protocol running at the transport layer is used to provide reliable and transparent end-to-end data transmission services to the upper layer using services provided by the lower layer.

  1. The characteristics of wireless sensor network transmission protocol

    • Characteristics of traditional transport protocols

      Including TCP and UDP, but not applicable to wireless sensor networks

    • The characteristics of wireless sensor network transmission protocol

      • Energy conservation priority
      • Many-to-one transmission
      • Data-centric
      • Strong application correlation

  2. Classification:

    • Congestion control protocol
    • Reliable Transport Protocol
    • A hybrid protocol for congestion control and reliable transport

6.2.5 Protocol standards for WIRELESS Sensor Networks

  • 802.15.4
  • ZigBee

6.3 Control technology of wireless sensor network

6.3.1 Time synchronization technology in WIRELESS Sensor networks

  1. The necessity of time synchronization

    • Collaboration needs
    • Energy demand

  2. Characteristics of time synchronization in wireless sensor networks

    • Energy efficiency
    • Synchronization accuracy
    • Synchronization life
    • Synchronous range
    • scalability
    • reliability

  3. Technical challenges

6.3.2 Topology control technology of wireless sensor networks

  1. concept

Network topology refers to the physical connection structure of network nodes formed by the interconnection of transmission media

  1. The need for
    • Improve the energy efficiency of the network
    • Improve network communication efficiency
    • Improve the efficiency of routing protocols
    • Improve data fusion efficiency
    • Improve network scalability
    • Ensuring network reliability
  2. challenge

6.3.3 Wireless Sensor network positioning technology

  1. The characteristics of

    • Self-organizing characteristic
    • Energy saving features
    • Distributed feature
    • robustness
    • scalability

  2. Technical challenges

Chapter 7: Technologies supporting iot applications

* * 7.1 cloud computing

7.1.1 Concepts and Features

  1. classification

    • Public cloud: Provides open computing and storage services to the public
    • Private cloud: provides services for a specific organization
    • A hybrid cloud

  2. Features:

    • Very large scale
    • virtualization
    • High reliability
    • generality
    • High scalability
    • On-demand service
    • Very cheap

  3. The basic principle of

    By distributing computing over a large number of distributed computers, rather than local computers or remote servers, enterprise data centers will operate more like the Internet

7.1.2 Service Mode and Key technologies

  1. Service mode

    • SaaS: Software as a service
    • PaaS: Platform as a service
    • LaaS: Infrastructure as a service

  2. The key technology

    • Data storage technology
    • Data management techniques
    • Programming model

7.1.3 Cloud Computing and Internet of Things

  1. The relationship between cloud computing and iot: Cloud computing is the cornerstone of iot development

  2. How cloud computing and the Internet of Things come together

    • Single center, multiple terminals
    • Multi-center, large number of terminals
    • Stratified processing of information and application, massive terminal

7.3 Big Data and Its Fusion

7.3.3 Internet of Things Data Fusion

  1. Data fusion principles

In order to improve the quality of data and lay the foundation for knowledge extraction, multi-dimensional data can be correlated or comprehensively analyzed, and then appropriate fusion mode and processing algorithm can be selected.

  1. The key problem
    • Data fusion node selection
    • Data fusion timing
    • Data fusion algorithm
  2. The technical requirements
    • The stability of
    • Data correlation
    • Energy constraint
    • Scalability of the protocol

Chapter 8: Iot applications and solutions

8.1 Application fields and prospects of iot

8.1.1 Main application areas of iot

  1. Industry:

    • Manufacturing Supply Chain Management
    • Production process optimization
    • Monitor and manage product equipment
    • Environmental monitoring and energy management
    • Industrial safety production management

  2. Agriculture:

    • Collection and control of greenhouse environmental information
    • Control and management of water saving irrigation
    • Monitoring of environmental information and animal and plant information

  3. Smart grid

  4. Smart home

  5. Intelligent medical

  6. City security

  7. The environmental monitoring

  8. Intelligent transportation

  9. Intelligent judicial

  10. Logistics…

8.4 Smart Home Applications and Solutions

8.4.1 Smart Home Applications and Solutions

  1. The most reliable smart home technology on the market
    • Centralized wiring technique
    • Radio frequency technology
    • X10 store carrier technology
    • ZigBee wireless networking communication technology