WPAN definition
Wireless Personal Area Network Communication Technologies is abbreviated as WPAN. WPAN is a personal area network that uses wireless connections.
In addition to 802.15 based on Bluetooth technology, IEEE also recommends 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), wireless personal area network (WPAN) is to achieve small activity radius, An emerging wireless communication network technology that is rich in business types, oriented to specific groups, and wirelessly seamlessly connected.
A wireless personal area network (WPAN) is a wireless network formed by interconnecting several devices in a small area, usually within the reach of the equipment. The wireless personal network utilizes the openness and short-distance wireless communication technology of Bluetooth.
Wireless Personal Area Network (WPAN) is short-distance wireless communication technology. Its basic idea is to use radio or infrared instead internet of traditional wired cables to realize the intelligent interconnection of personal information terminals and form personalized information.
In terms of network composition, WPAN is located at the end of the entire network chain and is used to solve the connection between terminals and terminals at the same location, such as connecting mobile phones and Bluetooth headsets.
WPAN is a dedicated network based on computer communication. It is a network composed of devices that need to communicate with each other in a personal operating environment without any central management device.
For a single device, it is required to be able to provide both the master control function and the slave function. In addition, equipment is also required to be able to easily access or leave the existing network. The system should be suitable for running various types of files such as images, MP3s, and video clips.
This is a small-range wireless communication system with a coverage radius of only about 10m. It can be used to replace communication cables for smart devices such as computers, mobile phones, PDAs, and digital cameras, or to form wireless sensor networks and smart home networks.
WPAN is not a technology that competes with wireless local area networks (WLAN). WLAN can replace wired local area networks. WPAN does not need the support of basic network connections and can only provide low-speed connections between a small number of small devices.
WPAN classification
WPAN is divided into a low-speed wireless personal network and a high-speed wireless personal network.
Low-speed wireless personal network
IEEE 802.15.4 (Low Rate Wireless Personal Area Network) network equipment is divided into two categories.
The first type of Full Functional Device (FFD) supports all network functions and is the core part of the network.
The second category is that some functional devices (Reduced Functional Devices, RFD) only support the minimum necessary network functions. Generally, most of the networks are such devices.
Wireless personal networks generally have two networking forms, a star network, and a cluster network.
In a star network, a complete function device is the network center; in a cluster network, on the basis of several star networks, the complete function devices in the center are connected to each other to form a tree network.
The main characteristics of the physical layer are 868 MHz, and 915 MHz, and a total of 27 channels on the 2.4GHz ISM frequency band.
Among them, channel 0,868～868.6 MHz, center frequency 868.3 Hz, BPSK modulation, providing 20Kb/s data path;
The center frequency of channels 1～10 is 906+2x (channel number -1) MHz, BPSK modulation, and each channel provides a 40Kb/s data path;
Channel 11~26 center frequency = 2405+5x (channel number -11) MHz, O-QPSK modulation, each channel provides 250Kb/s data path. The main feature of the media access control layer is CSMA/CA access and an optional superframe time-sharing mechanism.
High-speed wireless personal network
The high-speed wireless personal network (WPAN) works in the 2.4GHz frequency band without a license, and the maximum rate can reach 55 Mb/s.
(1) Classification of high-rate wireless personal networks: The applications of high-rate WPAN can be divided into two categories. The first category involves the transmission of bulk (multi-megabyte) data files; the second category involves real-time video and high-quality sound.
(2) The application of high-speed wireless personal network: In the first type of application, it is the application of digital cameras and video cameras that store multi-megabyte photo files and video streams in digital format. Research on consumer psychology shows that users are usually dissatisfied when the transmission time exceeds 7 to 15 seconds.
Using Bluetooth technology, it takes about 1 minute to transfer a data file containing a 3MB image or video stream from a camera to a PC. If you need to transmit multiple such documents, the 1Mb/s data rate provided by Bluetooth technology is obviously not enough, at least an order of magnitude higher.
Another application is related to the delivery of music files in MP3 or CD format. We hope to transfer these files between a PC and an MP3 player or CD player. However, the information volume of an MP3 file containing only one song is often greater than 3MB. If you want to complete the transmission within 7 to 15 seconds, the physical layer data rate must exceed 1Mb/s.
WPAN standard
IEEE 802.15.1 is the first WPAN technical standard proposed by IEEE to replace wired connections. Based on Bluetooth technology, the effective data rate of transmission is 500-700Kb/s, which can support voice and data services and provide multi-level security mechanisms.
The basic unit of the Bluetooth system is a piconet, which includes a master node and up to 7 active slave nodes within a distance of 10 meters. And multiple piconets can be connected by bridging points to form a statement.
Because it works in the ISM frequency band, in order to improve the anti-interference ability of the channel, Bluetooth uses fast frequency hopping and short packet communication technology.
Bluetooth also implements link error control through forwarding error correction coding (FEC) and fast automatic repeat request (ARQ). The layer structure of the Bluetooth protocol does not comply with the OSI model or the TCP/IP model.
The IEEE 802.15.2 standard was launched in August 2003 to solve the coexistence problem between WPAN and WLAN, thereby promoting the application of IEEE 802.15 wireless personal networks.
Coexistence means that it can work with other wireless devices (such as IEEE 802.11 devices) operating in the open frequency band in a common space at the same time without interfering with each other. Moreover, the standard proposes amendments to other 802.15 standards to improve this coexistence performance.
The IEEE 802.15.3 standard, which was passed in August 2003, aims to obtain a higher data transmission rate while being compatible with Bluetooth. Its data transmission rate can be as high as 55 Mb/s. The high-speed WPAN can support a data rate of 110-480Mb/s, which is suitable for the transmission of a large number of multimedia files, video, and MP3 audio files in a short time.
The IEEE 802.15.4 standard published in October 2003 defines a low-power and low-speed wireless connection technology, which aims to delay battery life and reduce device costs. Its rate can be as low as 9.6Kb/s, but it does not support voice service.
WPAN features
Most wireless personal local area networks work in the 2.4GHz frequency band (HiperLAN2, UWB, IrDA do not work in the 2.4GHz frequency band), and these technologies have the following advantages.
1) Support mobile networking, users can move the location of the computing device as flexibly as using a mobile phone, and maintain a continuous network connection.
2) There is no need to use physical wiring and the installation is very simple. Because the high-frequency radio waves used by wireless networks can penetrate walls or glass windows, network devices can be placed arbitrarily within the effective range.
3) Multi-layer security protection measures can fully ensure user privacy.
4) When changing the network structure or layout, there is no need to reset the network.
WPAN is a wireless network that is parallel with a wireless wide area network (WWAN), wireless metropolitan area network (WMAN), and wireless local area network (WLAN) but has a relatively small coverage area.
In terms of network composition, WPAN is located at the end of the entire network chain and is used to realize the connection between terminals and terminals at the same location, such as connecting mobile phones and Bluetooth headsets.
The range covered by 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.
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