WiFi

Wi-Fi (Wireless Fidelity) is a wireless LAN technology that uses wireless signals to connect devices and networks. Wi-Fi technology allows users to transmit data and access the Internet through wireless signals without using a wired connection. Wi-Fi technology has become an indispensable part of modern life and is widely used in various occasions such as homes, offices, commercial places and public areas.

WiFi technology originated in 1997 and was invented by scientists from Australia's CSIRO (Commonwealth Scientific and Industrial Research Organization). They used a technology called "OFDM" (Orthogonal Frequency Division Multiplexing) to successfully increase the data transmission speed to 2Mbps. This technology was later incorporated into the IEEE 802.11 standard and became the basis of WiFi technology.

Mainstream WiFi standards

1. 802.11b: One of the earliest WiFi standards, operating in the 2.4GHz frequency band with a maximum transmission rate of 11 Mbps.
2. 802.11a: It is also an earlier WiFi standard, operating in the 5GHz band, with a maximum transmission rate of 54 Mbps.
3. 802.11g: Works in the 2.4GHz frequency band, with a maximum transmission rate of 54 Mbps, and is backward compatible with 802.11b.
4. 802.11n: Supports 2.4GHz and 5GHz frequency bands, with a maximum transmission rate of up to 600 Mbps, and uses MIMO technology to improve transmission rate and coverage.
5. 802.11ac: Working in the 5GHz band, the maximum transmission rate can reach 1 Gbps, using more advanced technology to improve speed and performance.
6. 802.11ax (Wi-Fi 6): One of the latest WiFi standards, supports 2.4GHz and 5GHz frequency bands, has higher transmission rates and better network capacity, and can better cope with high-density connection and data transmission needs.

WiFi security

1. Use encryption: Enable WPA3 or WPA2 encryption to protect your wireless network and avoid using WEP encryption as it is already insecure.
2. Change default credentials: Change the default username and password for your router and Wi-Fi network to use strong passwords and usernames.
3. Hide network name (SSID): Turn off broadcast network name (SSID) to hide your network so only people who know the network name can connect.
4. Enable firewall: Enable firewall on the router and connected devices to block unauthorized access and network attacks.
5. Update firmware: Update your router's firmware regularly to fix security holes and improve security.
6. Use a virtual private network (VPN): Use a VPN to encrypt data transfers when connected to public Wi-Fi to prevent data theft.
7. Disable WPS: Wi-Fi Protected Setup (WPS) has security vulnerabilities, and it is recommended to disable it to improve security.

These methods can help improve the security of your Wi-Fi network, but you also need to pay attention to regularly checking and updating security settings to deal with new security threats.

Bluetooth

Bluetooth is a wireless technology used to transmit data over short distances. It is usually used to connect mobile phones, headphones, speakers, keyboards, mice and other devices. Bluetooth technology enables wireless communication and data transmission between devices.

Bluetooth originated in 1994 and was jointly developed by Ericsson engineers Jaap Haartsen and Jim Carey (Sven Mattisson). Initially, their goal was to develop a technology that would enable wireless communication between mobile phones and other portable devices. With the development of technology, Bluetooth has become a standard widely used for short-distance wireless communication between various devices.

Common Bluetooth versions

1. "Bluetooth 1.0 and 1.1": The original Bluetooth version, with basic data transmission functions.
2. "Bluetooth 2.0 + EDR": Enhanced Data Rate, which improves data transmission speed and efficiency.
3. "Bluetooth 3.0 + HS": Introduces High Speed ​​mode to support faster data transmission speed and Wi-Fi collaboration.
4. "Bluetooth 4.0": Introduces Bluetooth Low Energy (BLE), which is suitable for low-power devices, such as smart watches, health monitoring equipment, etc.
5. "Bluetooth 4.2": Provides faster data transmission speed and stronger privacy protection functions.
6. "Bluetooth 5.0": further improves data transmission speed and coverage, supports multi-device connection and broadcast functions.
7. "Bluetooth 5.1": Introducing positioning and orientation functions, which can achieve more precise positioning and navigation.
8. "Bluetooth 5.2": Provides higher data transmission speed and lower power consumption, enhancing security and connection stability.

Development Trend of Bluetooth Technology

1. "Low power consumption": With the rise of the Internet of Things and wearable devices, the requirements for low power consumption of Bluetooth devices are getting higher and higher. Therefore, the development of Bluetooth technology in low power consumption will be an important trend.
2. "High-speed transmission": With the launch of Bluetooth 5.0 and later versions, the transmission speed of Bluetooth technology will continue to increase, allowing it to better support applications such as high-definition audio and video transmission.
3. "Mesh network": The emergence of Bluetooth Mesh network allows Bluetooth devices to build larger-scale networks, which is suitable for scenarios such as smart homes and smart buildings.
4. "Positioning and navigation": The development of Bluetooth positioning technology will make indoor positioning and navigation possible, providing more possibilities for indoor positioning applications.
5. "Security": As the application of Bluetooth increases in fields such as payment and access control, the security of Bluetooth technology will become a more important focus.

The development trend of Bluetooth technology will continue to develop in the directions of low power consumption, high-speed transmission, Mesh network, positioning navigation and security.

NFC

NFC refers to "Near Field Communication", which is a short-range wireless communication technology that allows devices to communicate without contact or within a very short distance. NFC is commonly used in mobile payments, access control systems, smart tags and other fields. In NFC communication, devices communicate with each other via radio waves, and the typical operating distance is within a few centimeters.

NFC technology originated in 2002 and was jointly developed by Philips and Sony. It is based on RFID (Radio Frequency Identification) technology and is capable of wireless communication and data transmission within short distances. NFC technology was initially used in fields such as mobile payments, smart tags and data transmission. Now it has been widely used in mobile payment, public transportation cards, access control systems and other scenarios.

NFC working mode

1. "Reader/Writer Mode": The device can read or write information from NFC tags or other compatible devices.
2. "Peer-to-Peer Mode": Two NFC devices can exchange information with each other for data transmission and sharing.
3. "Card Emulation Mode": The device can simulate an NFC card and allow other NFC devices to read its information. It is often used in scenarios such as mobile payment and access control systems.

Common NFC application scenarios

1. Contactless payment: Through NFC technology, users can use their mobile phones or other devices to make contactless payments, such as using mobile payment apps or bank cards.
2. Access control system: NFC technology can be used in access control systems. For example, company employees can use NFC cards or mobile phones for access control.
3. Transportation: NFC technology can be used to swipe cards to ride on buses, subways and other means of transportation, which is convenient and fast.
4. Information transfer: NFC can be used to quickly transfer information, such as sharing photos, contact information and other data between two devices.
5. Electronic identification: NFC technology can be used for identification applications such as electronic ID cards and access control cards.
6. Smart tags: NFC tags can be used for intelligent management of items. For example, NFC tags can be attached to store products to facilitate customers to obtain product information.

Comparison of WiFi, Bluetooth and NFC

• WiFi (wireless LAN): used for wireless network connection, which can realize interconnection between devices, and is often used for Internet access, file transfer and other functions.
• Bluetooth: A short-range wireless technology used for data transmission and communication between devices. It is often used to connect peripherals such as headphones, speakers, keyboards, and mice.
• NFC (Near Field Communication): A short-distance high-frequency wireless communication technology, used for short-distance data transmission and interaction, often used in mobile payment, access control cards, bus cards and other scenarios.