- BlueTooth technology
Bluetooth technology was developed by Ericsson, IBM, Intel, Nokia and Toshiba in May 1998. From the original Bluetooth V1.0 to Bluetooth V5.1, over a dozen versions of the revision to the current state of development.
Bluetooth is a short-range, low-cost wireless access technology using the 2.4ghz ISM public channel, mainly used for short-range voice and data transmission services. The working frequency band of bluetooth devices is 2.4GHz ISM band which can be freely used worldwide. Users do not need to apply to use, most countries use 79 frequency points, carrier frequency is (2402+k)MHz (k=0, 1, 2... 78), carrier frequency interval 1MHz. TDD time division duplex mode is adopted. The frequency hopping rate is 1600 hops/s, which makes the bluetooth system have high enough anti-interference ability and superior simple performance. Depending on its transmitting power, the effective communication distance between bluetooth devices is about 10~100m.
- WiFi (Wireless Fidelity)
WiFi(Wireless Fidelity) technology is based on IEEE802. The 11-series standard wireless network communication technology brand aims to improve the interoperability of wireless network products based on IEEE802.11 standard, which is held by the wi-fi Alliance. Simply put, WiFi is a wireless network technology that connects computers via the network, but now connects to the Internet via radio waves. The WiFi Alliance was established in 1999 as the Wireless Ethernet Compatibility Alliance(WECA), which was officially renamed as the WiFi Alliance in October 2002.
WiFi network ranges from 2.4ghz band of 802.11 to 5GHz band of 802.11a, then to 2.4ghz band of 802.11n and 5GHz compatible band, and then to 60GHz band of 802.11ad. After nearly ten versions of evolution, the latest 802.11ax has returned to the compatible frequency band of 2.4ghz and 5GHz, and can reach the speed of 9.6gbps.
WiFi covers a wide area, up to 100m, but its waves are easily disturbed and fast. The potential for data packets to be intercepted due to the use of radio waves as a transmission medium is also a concern for users. Currently, WiFi products use WED (Wired Equivalent Privacy) technology as data encryption.
- ZigBee
ZigBee is a short distance, low power, low rate wireless access technology. ZigBee is mainly used in various electronic devices with short distance range and low data transmission rate. Working in the 2.4ghz ISM band, the speed is 10K~250Kbps, and the transmission distance is 10~75m. The technology is similar to bluetooth, but ZigBee is simpler, slower, and lower in power and cost. Its top speed is 250K, when reduced to 28K, the transmission range can be extended to 134m, and obtain higher reliability. In addition, it can connect to 254 nodes. Better support for games, consumer electronics, instrumentation, and home automation applications than bluetooth. But ZigBee is mostly in sleep mode, which is suitable for situations where real-time transmission or continuous updates are not required. ZigBee is an extended set of IEEE 802.15.4. The physical layer standard adopts three frequency bands: 2.4GHz in North America, 915MHz and 868MHz in Europe.
ZigBee's name comes from the communication mode that bees rely on for survival and development. Bees share information about the location, distance and direction of newly discovered food sources through ZigZag shaped dance.
The ZigBee alliance was founded in August 2001. In the second half of 2002, Invensys, Mitsubishi, Motorola and Philips semiconductor corporation jointly announced to join the ZigBee alliance to develop the next generation wireless communication standard named ZigBee. So far, the alliance has about 27 member companies. All of these companies participated in the IEEE 802.15.4 working group responsible for developing the ZigBee physical and media control layer technology standards. The ZigBee alliance is responsible for establishing protocols above the network layer. The ZigBee protocol is simpler and more practical than bluetooth, high rate personal area network or 802.11x wireless LAN.
- IrDA(Infrared Data Association)
The IrDA(InfraredData Association) was founded in 1993. Initially, wireless devices using the IrDA standard were able to transmit data at 115.2 kilobytes per second in the range of 1 Megabyte, but quickly grew to speeds of 4 megabits per second and 16 megabits per second. IrDA, a point-to-point communication technology using infrared light, is the first technology to implement a wireless personal area network (PAN). At present, its software and hardware technologies are mature and widely used in small mobile devices, such as pdas and mobile phones. In fact, every single PDA today and many cell phones, laptops, printers, and more support IrDA.
The main advantage of IrDA is that there is no need to apply for the right to use the frequency, so the cost of infrared communication is low. It also has the characteristics of small size, low power consumption, convenient connection and easy to use. In addition, the infrared emission Angle is small, the transmission safety is high. The drawback of IrDA is that it is a line-of-sight transmission in which two communicating devices must be aligned and cannot be separated by other objects, so the technology can only be used to connect two (but not more) devices. Bluetooth, on the other hand, has no such restrictions and is not blocked by walls. The current research direction of IrDA is how to solve the problem of line-of-sight transmission and improve the data transmission rate.
- UWB (Ultra WideBand)
UWB(Ultra Wideband) is a wireless carrier communication technology, which does not use sinusoidal carrier but USES nanosecond narrow non-sinusoidal pulse to transmit data, so it occupies a wide spectrum. It has great advantages in short distance transmission (under 13m), with the highest transmission speed up to 1Gbps, while traditional narrow-band technology has advantages in long distance and low speed transmission.
UWB can transmit signals in a very wide bandwidth. According to the regulations of FCC in the United States, UWB occupies a bandwidth of more than 500MHz in the band of 3.1 ~ 10.6ghz. UWB has developed rapidly in recent years because it can realize high-speed data transmission by using low-power and low-complexity transmitter/receiver. It USES low power pulse to transmit data in a very wide spectrum without disturbing conventional narrowband wireless communication system and can make full use of spectrum resources. High rate data transceivers based on UWB technology have a wide range of applications.
UWB technology has the advantages of low system complexity, low transmitted signal power spectrum density, insensitivity to channel fading, low interception ability and high positioning accuracy. It is especially suitable for high-speed wireless access in indoor and other dense multipath places, and it is very suitable for the establishment of an efficient wireless local area network or wireless individual domain network (WPAN).
UWB is mainly used in small scale, high resolution radar and image systems that can penetrate walls, ground and body. In addition, this new technique is appropriate for LANs or panes that require very high rates (greater than 100Mb/s).
The most distinctive applications of UWB will be wireless personal lans in consumer entertainment, video. The current wireless communication mode, 802.11b and bluetooth, is too slow to transmit video data. The 802.11a standard of 54Mb/s can handle video data, but it is expensive. While UWB may be within the range of 10m and supports data transmission rate up to 110Mb/s. It does not need to compress data and can quickly, simply and economically complete video data processing. Has certain compatibility and the advantages of high speed, low cost, low power consumption makes UWB wireless consumer market is more suitable for family needs: UWB is especially suitable for high speed transmission of multimedia data in close range and can penetrate the prominent advantages of obstruction to let many commercial companies see it as a very promising wireless communication technology, applied in areas such as the video signal from a set-top box wirelessly to the domestic situation, such as digital television. Of course, the future of UWB will also depend on the technical development, cost, user habits and market maturity of various wireless solutions.
- WiMAX(Worldwide Interoperability for spotted Access)
Worldwide Interoperability for Microwave Access (WiMAX) is a standard for high-speed wireless data networks. This standard is mainly used in metropolitan area networks. It was introduced by WiMAX BBS in June 2001. It offers at least one mile of wireless broadband access as an alternative to cable and DSL. Choose only among multiple versions and options of the IEEE 802.16 standard to ensure interoperability between products from different vendors. In 802.16 the physical layer of three variants, WiMAX chose 802.16-2004 version of the 256 carrier OFDM, can borrow by wide frequency band and the transmission distance is far, to assist the telecom operators and Internet service providers are establishing the last mile of the wireless Internet, and mainly for the purpose of short distance transmission area of IEEE 802.11 has quite a different communication protocol.
WiMAX offers a wide range of applications, including last-mile wireless broadband access, hot spots, backhaul lines for mobile communications, and high-speed connections between enterprises for business use. Products that pass the WiMAX conformance test are all able to create wireless connections to each other and send Internet packet data. Similar to WiFi in concept, WiMAX has a faster transmission rate and a larger range, which can be simply understood as a "large WiFi".
Wireless man-advanced (IEEE 802.16m), an upgrade of WiMAX, is one of two 4G standards.
- NFC(Near Field Communication)
NFC(Near Field Communication) is a short-range wireless Communication technology standard similar to RFID(non-contact radio frequency identification), mainly promoted by Philips, NOKIA and Sony. Different from RFID, NFC USES bidirectional identification and connection. Operating in the 13.56mhz frequency range at a distance of 20cm. NFC started out as a combination of remote control identification and networking, but has evolved into wireless connectivity. It quickly and automatically establishes a wireless network, providing a "virtual connection" for cellular devices, bluetooth devices, and wi-fi devices, allowing electronic devices to communicate over short distances. The short distance interaction of NFC greatly simplifies the whole authentication and identification process, making the mutual access between electronic devices more direct, safer and clearer, without hearing various electronic noises. By combining all the identity applications and services on a single device, NFC helps solve the problem of remembering multiple passwords, while ensuring the security of data. With NFC, it is possible to exchange data or services between multiple devices such as digital cameras, pdas, set-top boxes, computers and mobile phones through wireless interconnection. NFC can also "accelerate" other types of wireless communication, such as wi-fi and bluetooth, to allow faster and longer data transfers. Each electronic device has its own dedicated application menu, and NFC can create fast and secure connections without having to choose from many interface menus. Unlike well-known short-range wireless communication standards such as bluetooth, NFC functions at a much shorter distance and does not require a corresponding encryption device as bluetooth does. Similarly, building a wi-fi family wireless network requires multiple computers, printers and other devices with wireless network CARDS. In addition, it takes a skilled professional to do the job. An NFC can be placed in an access point and two of them can be placed close enough to communicate, much easier than configuring a wi-fi connection.
NFC has three types of applications: one is device connectivity. In addition to wireless lans, NFC can also simplify bluetooth connectivity. For example, to access the Internet at an airport, laptop users need only approach a wi-fi hotspot. Second, real-time reservation. For example, posters or exhibition information with a specific chip on the back, using the NFC protocol of the mobile phone or PDA, access to detailed information, or immediately online with a credit card ticket purchase. Moreover, these chips do not need independent energy sources. The third is mobile commerce. Philips Mifare supports several of the world's largest transport systems and offers everything from Visa CARDS in the banking industry. SONY's FeliCa contactless smart card technology has a high market share in Hong Kong, shenzhen, Singapore and Japan, mainly used in transportation and financial institutions. In short, this new technology is rewriting the rules of the wireless network connection game, but the goal of NFC is not to completely replace bluetooth, wi-fi and other wireless technologies, but to complement each other in different places and in different fields.
- RFID(Radio Frequency Identification)
Radio Frequency Identification (RFID) is short for Radio Frequency Identification. , is an emerging automatic identification technology developed in the 1980s. Rfid technology is a technology that USES radio frequency signals to realize non-contact information transmission through spatial coupling (alternating magnetic field or electromagnetic field) and achieves identification purpose through the transmitted information.
RFID is a simple wireless system. The complete RFID system consists of Reader, Tag and data management system.
RFID radio frequency identification (RFID) is a non-contact automatic identification technology. It can automatically identify target objects and obtain relevant data through radio frequency signals. The identification work needs no manual intervention and can work in various harsh environments. RFID technology can identify high-speed moving objects and can identify multiple tags at the same time, the operation is fast and convenient.
Its working principle is that the label into the magnetic field, after receiving radio frequency signal from the read/write device, with the energy gained by the induced current send product information stored in the chip (Passive Tag, Passive tags or Passive tags), or by label initiative to send a frequency signal (Active Tag, Active tags or Active tags), the reader reads the information and the decoding, sent to the data management system on data processing.
RFID technology can be divided into three categories according to the power supply mode of its tags, namely passive RFID, active RFID, and semi-active RFID.
- LiFi (Light Fidelity)
Visible Light wireless communication is also called the "Light" Fidelity technology, English name Light Fidelity (hereinafter referred to as LiFi) is a kind of using visible Light spectrum (such as the Light bulb) for data transmission, a new wireless transmission technology, from the university of Edinburgh, chairman of the mobile communication department of electronic communications, German physicist Harald Hass (Harald haas), a professor of invention.
Visible-light wireless communication technology USES laid devices (ubiquitous LED lights) to create ap-like devices by embedding a tiny chip in the bulb, allowing the terminal to access the network at any time. The technology transmits data by changing the flicker frequency of a room's lighting, allowing it to connect to the Internet without WiFi by turning on the lights indoors.
Visible light wireless communication technology is to use visible light to achieve wireless communication, that is, the use of electrical signal control LED (LED) issued by the naked eye can not see the high-speed flashing signal to transmit information.
- Thread
Thread is an ip-based wireless network protocol used to connect smart products in your home. Thread Group was founded on July 15, 2014 to collaborate, share expertise, and develop solutions to meet these needs. A year after its inception, Thread Group released the Thread specification. Founding members of the group include SiliconLabs, Nest Labs, Yale Security, Samsung Electrics, Freescale Semiconductor, Big Ass Fans and ARM.
Thread's focus on low power consumption and inherent support for IP delivers the promise of seamless connectivity between everything and the web. It provides effective communication not only between low-cost, battery-powered devices, but also simple interfaces to the cloud and mobile devices. Thread offers attractive new wireless mesh network solutions designed to meet the following home connectivity needs:
Standards-based protocols: open standards-based protocols for interoperability and competitiveness across vendors. Thread builds on current IEEE and IETF standards, including IEEE802.15.4. The official Thread Specification was released by Thread Group on July 13, 2015.
Simplified configuration: Thread removes some of the complexity of previous mesh network standards. There are only two different node types: routersubscriptions and End Device.
The Router Router node becomes the Router that needs to support the mesh network. The first Router Router node that builds the network is automatically designated as a Router and as a Leader. The Leader performs additional network management tasks and makes decisions on behalf of the network. Other routers in the network are automatically Eligible for the Leader role, but only one Leader per network at a time.
The nodes added as End Device do not support any routing functions. Instead, they send information to a router designated as a "parent", which performs routing operations on behalf of its "children". The End Device routes through its parent and can enter the "Sleepy" state to reduce power consumption. End devices that cannot communicate with their parent automatically scan and connect to the new parent after multiple attempts.
- Mesh
Wireless Mesh network is a new type of wireless LAN. Different from traditional WLAN, AP in wireless Mesh network can be connected wirelessly, and multi-hop wireless links can be established between AP.
Wireless mesh network, the mesh routers (router) and the mesh clients (the client), including mesh routers constitute the backbone network, and connected to the Internet network of the cable, for the mesh clients provide more wireless Internet connection. Therefore, wireless Mesh networks are also called multi-hop networks.
In traditional wireless local area network (WLAN), each client accesses the network through a wireless link connected with AP(Access Point), forming a local BSS(Basic Service Set). To communicate with each other, users must first access a fixed access point (AP), a network structure known as a single-hop network.
However, in the wireless Mesh network, any wireless device node can act as AP and router simultaneously. Each node in the network can send and receive signals, and each node can communicate directly with one or more peer nodes.
Compared with the traditional switched network, wireless Mesh network eliminates the routing requirement between nodes, but still has the redundant mechanism and rerouting function provided by distributed network.
To add a new device to a wireless Mesh network, you simply plug it in, configure it automatically, and determine the best multi-hop path. When adding or moving devices, the network can automatically detect topology changes and automatically adjust communication routes to obtain the most efficient transmission path.
The key technologies involved in the implementation of wireless Mesh network mainly include: multi-channel negotiation, channel allocation, network discovery, routing and forwarding, Mesh security and so on.
- Z - Wave
Z-wave is a wireless networking specification led by Danish Zensys. Although z-wave Alliance is not as strong as ZigBee Alliance, its members are all manufacturers that already have existing products in the field of smart home. The Alliance has more than 160 internationally renowned companies, covering basically all countries and regions in the world.
Z-wave is a new wireless communication technology based on rf, low cost, low power consumption and high reliability. Focus on low rate applications, using FSK (BFSK/GFSK) modulation mode, there are 9.6Kbit/s and 40Kbit/s two transmission rates, the former used to transmit control command more than enough, and the latter can provide a more advanced network security mechanism. It operates in flexible frequency bands, such as 900MHz (ISM (Industrial Scientific Medical) band), 868.42mhz (Europe), and 908.42mhz (USA), with relatively few devices operating in these bands, while the 2.4ghz band used by ZigBee or bluetooth is becoming increasingly crowded and mutual interference is inevitable, so z-wave technology can better guarantee the reliability of communication. The effective coverage range of z-wave signal is 30m indoors and 100m outdoors, suitable for narrow bandwidth application scenarios.
