Short-range wireless communication technology is a communication method based on radio waves that is used to transmit data and information over relatively short distances. Compared with traditional wired communication methods, short-range wireless communication technology does not require physical connections and can provide more flexible and convenient data transmission solutions.

One of the advantages of short-range wireless communication technology is that it eliminates the physical connection limitations in traditional wired communications, allowing for freer communication between devices. There is no need to worry about the length of the cable or the compatibility of the connecting plug. Short-range wireless communication technology can realize plug-and-play between devices, greatly simplifying the installation and wiring process of the equipment. In addition, short-range wireless communication technology also provides greater flexibility and mobility, allowing devices to be moved between different locations without worrying about communication interruption.

However, short-range wireless communication technology also has some disadvantages. First of all, since wireless communication is affected by the environment, such as obstacles, interference sources, etc., the signal transmission distance and quality may be limited. In addition, because wireless communications use shared spectrum resources, interference may occur between devices, resulting in reduced communication quality or slower data transfer rates. In addition, compared with wired communication, the security of short-range wireless communication technology may also present challenges, requiring additional security measures to protect data transmission and storage.

Despite some limitations, short-range wireless communication technology is still widely used in various fields. From home networks and smart homes to industrial automation and the Internet of Things, short-range wireless communication technology provides us with convenient data transmission and information exchange methods, which has greatly promoted the development and application of modern technology.

1. Wi-Fi technology
In theory, with WiFi technology, the user is located in a certain area around the access point, but if blocked by a wall, the effective transmission distance inside the building will be less than outdoors. WiFi technology is mainly used in buildings and places where it is inconvenient to install cables, such as SOHO, shopping malls, airports, home wireless networks, airports, hotels, and other public hotspots, saving a lot of cable laying costs.

2.Bluetooth technology
An open global specification for wireless data and voice communications. The technology applied by Bluetooth technology is to establish a universal short-range wireless interface in the communication environment between fixed or mobile devices. The Bluetooth module transmission band is the world-wide 2.4GHz ISM band. Provides a transmission rate of 1Mbps and a transmission distance of 10m.

Disadvantages of Bluetooth technology: chip size and price are difficult to reduce, anti-interference is not strong, transmission distance is too short, information security issues, etc.
Bluetooth technology
3.ZigBee technology
ZigBee technology is mainly used between various electronic devices within short distances, and the data transmission speed is not high. The name ZigBee comes from the communication method used by bee colonies to survive and thrive. Bees dance in zigzags, sharing the location, distance and direction of newly discovered food. ZigBee can be said to be a brother of the same Bluetooth family. This family uses the 2.4GHz frequency band and uses frequency hopping technology. But ZigBee is simpler and slower than Bluetooth, with lower power consumption and cost. The basic rate is 250kb/s. When it is reduced to 28kb/s, the transmission range can be extended to 134m, which can achieve higher reliability. It can also connect to 254 nodes and networks. Better support for games, appliances, devices and home automation applications than Bluetooth.
ZigBee technology
4.IrDA technology
IrDA technology is a technology that uses infrared rays for point-to-point communication and is the first technology to realize wireless personal area networks (PAN). At present, its software and hardware technology are very mature, supporting IrDA on small mobile devices such as PDAs, mobile phones, laptops, printers and other products.

Advantages: No need to apply for use rights, low-cost infrared communication, small size, low power consumption, convenient connection, simple and easy to use required for mobile communications, small infrared radiation angle, and high transmission security.

Disadvantage: This technology can only be used for connections between two (not multiple) devices. Bluetooth technology does not have this limitation, so IrDA's current research direction is to solve the line-of-sight transmission problem and improve the data transmission speed.
IrDA technology
Short-range wireless communication technology standards such as RFID (contactless radio frequency identification) promoted by Philips, Nokia and Sony. Unlike RFID, NFC uses two-way identification and connection. The operation is within the frequency range of 13.56MHz and the distance is 20cm. NFC was originally just a combination of remote control identification and network technology, but now it has gradually developed into a wireless connection technology.

NFC solves the problem of storing multiple passwords by combining all identification applications and services on one device, ensuring data security. Using NFC, multiple devices (such as digital cameras, PDAs, set-top boxes, computers, mobile phones, etc.) can be wirelessly interconnected and exchange data and services with each other. Likewise, building a Wi-Fi family of wireless networks requires devices with multiple computers, printers, and other wireless cards. Some technical experts have also been asked to complete the work. After setting up NFC on the access points, you can communicate if two of them are off, much easier than setting up a Wi-Fi connection.
6.UWB ultra-wideband technology
UWB is also called wireless carrier communication technology. Because it uses nanosecond-scale non-sinusoidal narrow pulses instead of sine wave carriers to transmit data, UWB can transmit signals with a very wide bandwidth. According to the FCC regulations in the United States, it occupies a large spectrum. UWB occupies more than 500MHz of frequency band in the 3.1 to 10.6GHz frequency band.

UWB has developed rapidly in recent years because it can achieve high-speed data transmission using low-power, low-complexity transceivers. Using low-power pulses, data can be transmitted over a very wide spectrum and utilize spectrum resources without causing significant interference to traditional narrowband wireless communication systems. High-speed data transceivers based on UWB technology have a wide range of uses.

The advantages of UWB technology are low system complexity, low power spectral density of transmitted signals, insensitivity to channel fading, low interception capability, and high positioning accuracy. It is particularly suitable for high-speed wireless access in high-density multi-path sites such as indoors, and for building efficient wireless LANs and wireless personal LANs (wpan). UWB is mainly used in narrow range, high-resolution radar and imaging systems that can be penetrated by walls, floors, and human bodies.

In addition, this new technology is also suitable for LANs and PANs that require very high speeds (above 100Mb/s), where optical fiber is expensive. Generally, UWB can achieve transmission performance of up to hundreds of Mbps within 10m, but the performance of IEEE802.11b or HomeRF wireless PAN for remote applications is stronger than UWB. UWB will not directly compete with the popular IEEE802.11b and home RF, as UWB is used a lot indoors at about 10m away.
UWB ultra-wideband technology
7. Other wireless communication technologies
Nowadays, the RFID technologies integrated with mobile phones are mainly NFC (Near Field Communication), SIMpass (dual interface SIM card) and RF-SIM (mobile phone smart card capable of medium and short distance wireless communication) technology.

SIMpass technology is a combination of DI card technology and SIM card technology, and is called a dual-interface SIM card. SIMpass is a multifunctional SIM card that supports contact and contactless working interfaces. The contact interface implements the SIM function, and the contactless interface implements the payment function. Compatible with multiple smart card application specifications.