Summary of core technologies and solutions for personal area networks

PAN is the abbreviation of Peonal Area Network, which refers to personal area network. Wireless personal area network (WPAN) is a personal area network that uses wireless connection. It is used for communication between devices such as phones, auxiliary devices and digital assistants within a small range (the working range of personal area network is generally within 10 meters).

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1. Basic Definition

In recent years, with the development of various short-distance technologies, people have proposed a new concept, namely Personal Area Network (PAN).

The core idea of ​​PAN is to use radio or wires instead of traditional wired networks to realize the intelligent interconnection of personal information terminals and build a personalized information network. From the perspective of computer networks, PAN is a local area network; from the perspective of telecommunications networks, PAN is an access network, so some people call PAN the "last one meter" solution for telecommunications networks.

PAN is positioned in home and small office applications, and its main application areas include voice communication gateways, gateways, information appliance interconnection, and automatic information exchange.

Wireless Personal Area Network (WPAN) is an emerging wireless communication network technology proposed to achieve a small activity radius, rich service types, specific groups, and seamless wireless connection. WPAN can effectively solve the problem of "long cables" and further promote wireless networking.

WPAN is a wireless network that is on par with wireless wide area network (WWAN), wireless metropolitan area network (WMAN), and wireless local area network (WLAN), but has a relatively smaller coverage area. In terms of network structure, WPAN is located at the end of the entire network chain and is used to connect terminals at the same location, such as connecting mobile phones and headphones. The coverage area of ​​WPAN is generally within a radius of 10m and must operate in a licensed wireless frequency band. WPAN equipment has the advantages of low price, small size, easy operation, and low power consumption.

2. Principles and methods

The main technologies for implementing PAN are: Bluetooth, IrDA, Home, and UWB (Ultra-Wideband Ro).

Technologies supporting wireless personal area networks include: Bluetooth, ZigBee, Ultra-Wide Band (UWB), IrDA, HomeRF, etc., among which Bluetooth is the most widely used technology in wireless personal area networks. Each technology can only play its best role when it is used for a specific purpose, application or field. In addition, although in some aspects, some technologies are considered to compete with each other in the wireless personal area network space, they are often complementary to each other.

The Institute of Electrical and Electronics Engineers (IEEE) 802.15 Working Group is the organization that defines wireless personal area networks. In addition to 802.15 based on Bluetooth technology, IEEE has recommended two other types: low-frequency 802.15.4 (TG4, also known as ZigBee) and high-frequency 802.15.3 (TG3, also known as Ultra Band or UWB). TG4 ZigBee provides data transmission speeds of 20 Kbps or 250 Kbps for low-voltage and low-cost home control solutions, while TG3 UWB supports data transmission speeds between 20 Mbps and 1Gbps for multimedia.

3. Four indicators

• IrDA technology is the best choice for devices that require high transmission rate, few uses, small movement range and relatively low price, such as printers, scanners, digital cameras, etc.
• If the device has a wide range of activities and requires rapid interconnection with multiple devices, such as laptop computers, digital cordless phones, personal digital assistants (PDAs), mobile phones, etc., using Bluetooth or WPAN is ideal.
• HomeRF technology is very convenient for small companies or homes like villas, because the activity radius of these two environments is larger than the activity range specified by Bluetooth and WPAN, and is generally smaller than the radius of wireless LAN. But this does not mean that HomeRF's position is worry-free. Because if a technology wants to become an internationally recognized standard, its uniqueness is essential. HomeRF's advantage in transmission distance is likely to be defeated by Bluetooth.

4. Bluetooth Hot

Bluetooth technology is a short-range wireless communication technology that supports point-to-point and point-to-multipoint voice and data services. The development of Bluetooth technology has greatly promoted the development of PAN technology. The original intention of Bluetooth design is to use a small, low-cost and low-power wireless communication technology to form a network around individuals, so that various information-based mobile or fixed devices within its coverage can "seamlessly" share resources. Its essence is to establish a common open standard for radio air and its control software, so that communication and computers can be further combined, so that such devices produced by different manufacturers can have interoperability and interoperability within a short range without or cables connecting each other. Because Bluetooth technology can be easily embedded in a single CMOS chip, it is particularly suitable for small mobile communication devices.

5. ZigBee is gaining attention

ZigBee technology is very secure, and there has been no precedent for cracking it in the world so far. Its security comes from its systematic design: it uses AES encryption (advanced encryption system), which is 12 times more stringent than bank card encryption technology; secondly, Zigbee uses a honeycomb structure to form a network, and each device can communicate with the gateway in multiple directions, with high network stability; in addition, its network capacity is theoretically 65,300 nodes, which is enough to meet the needs of home network coverage, and even smart communities and smart buildings can still be fully covered; finally, Zigbee has the ability of two-way communication, which can not only send commands to devices, but also feedback the execution status of the devices, which is crucial to the terminal user experience, especially security equipment. If you click to close the door, but don’t know whether the door is really closed, how much safety risks will it bring; in addition, Zigbee uses an extremely low power consumption design and can be fully powered. In theory, a battery can be used for more than 10 years, which is energy-saving and environmentally friendly.

Generally speaking, IrDA is more suitable for devices that require high transmission rate, few times of use, small range of movement, and relatively low price, such as printers, scanners, digital cameras, etc.; IEEE802.11 has a long transmission distance and fast speed, and is more suitable for wireless networks with longer distances in companies and enterprises. HomeRF technology is more suitable for communication in home environments, because the activity radius of such environments is larger than the activity range specified by Bluetooth technology, and is generally smaller than the radius of IEEE 802.1l. Bluetooth technology has fast frequency hopping, low power consumption, and strong flexibility, so it has more advantages in the interconnection of mobile devices, especially for devices with a wide range of activities and the requirement to be able to quickly connect to multiple devices, such as: laptops, digital cordless phones, PDAs, mobile phones, etc., making it more attractive and competitive in the emerging field of personal area networks.