WiFi Development | Introduction to WiFi Wireless Technology

Introduction to WiFi Wireless Technology

1. WiFi Technology Overview

WLAN is the abbreviation of Wireless Local Area Network, which is a system that uses wireless technology to transmit data. The emergence of this technology can make up for the shortcomings of wired local area networks and achieve the purpose of network extension.

Wi-Fi is the abbreviation of Wireless Fidelity. In the field of wireless local area networks, it refers to "wireless compatibility certification". It is essentially a commercial certification and also a wireless networking technology. Like Bluetooth technology, it is a short-range wireless technology used in offices and homes. Compared with Bluetooth technology, it has a higher transmission rate and a longer transmission distance, and has been widely used in notebooks, mobile phones, automobiles and other fields.

WIFI is a trademark of the Wireless LAN Alliance. This trademark only guarantees that products using the trademark can cooperate with each other and has nothing to do with the standard itself. However, because WIFI mainly uses the 802.11b protocol, people have gradually become accustomed to calling the 802.11b protocol WIFI. In terms of inclusion, WIFI is a standard of WLAN. WIFI is included in WLAN and is a new technology that adopts the WLAN protocol.

WiFi is a wireless network composed of wireless access points (APs), stations, etc. AP is generally called a network bridge or access point. It acts as a bridge between the traditional wired LAN and the wireless LAN. Therefore, any PC equipped with a wireless network card can share the resources of the wired LAN or even the wide area network through the AP. Its working principle is equivalent to a HUB or router with a built-in wireless transmitter, and the wireless network card is the CLIENT device responsible for receiving the signal transmitted by the AP.

2. Introduction to ESP8266

The WiFi development series will use the ESP8266 module to introduce WiFi wireless development technology. The ESP8266 module is a low-power UART-WiFi chip module developed by Essence based on Essence's ESP8266EX. It can be easily developed for secondary development, access cloud services, and achieve global control of mobile phones anytime, anywhere over 3/4G, accelerating product prototype design.

The module's core processor ESP8266 integrates the industry-leading Tensilica L106 ultra-low-power 32-bit micro MCU in a smaller package, with a 16-bit streamlined mode, a main frequency of 80 MHz and 160 MHz, RTOS support, integrated Wi-Fi MAC/BB/RF/PA/LNA, and an onboard antenna. Supports standard IEEE802.11 b/g/n protocols and complete TCP/IP protocol stack. Users can use this module to add networking capabilities to existing devices or build independent network controllers.

The ESP8266 module supports three working modes: STA, AP, and STA+AP.

• STA mode: The ESP8266 module is connected to the Internet through a router, and the PC or mobile phone can remotely control the device through the Internet.
• AP mode: ESP8266 module acts as a hotspot, PC or mobile phone communicates directly with the module to achieve LAN wireless control
• STA+AP mode: The two modes coexist. You can connect to the Internet through a router and control the device through the Internet; you can also use it as a WiFi hotspot for other WiFi devices to connect. Realize seamless switching between LAN and WAN
  

–STA：Station（站點），每個連接到無線網絡中的終端
–AP：Access Point（接入點），無線網絡的創建者，是網絡的中心節點

ESP8266 can be developed using the official SDK, or you can directly use the official firmware to configure the module using AT commands.

• AT command development: You only need to know a few AT commands to use an external microcontroller to achieve network communication. The development speed is fast, but the cost of the external MCU is increased.
• SDK development: The system has low cost, smaller size, and can realize more functions, but the entry threshold is high and it takes time to familiarize yourself with the code.

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