Recently, it is reported that we will hear the chip information supporting the 802.11ax standard at the upcoming International Consumer Electronics Show (CES) in 2017. It may be possible to see a few access point devices that support the standard. So what are the characteristics of the different IEEE 802.11 standards in WLAN? This article will explain in detail. The IEEE 802.15/Bluetooth, IEEE 802.11/WLAN, and IEEE 802.16/WiMAX technologies complement each other and play an important role in today's wireless communications. In 1990, the IEEE 802 Standardization Committee established the IEEE 802.11 Wireless LAN Standard Working Group. This standard defines the physical layer and media access control (MAC) specifications. The physical layer defines the signal characteristics and modulation of the data transmission and operates in the 2.4000 to 2.4835 GHz band. IEEE 802.11 is a wireless LAN standard originally developed by the IEEE. It is mainly used for wireless access of computers in difficult environments or mobile environments. Since the transmission rate can only reach 2 Mbps, services are mainly used for data access. In 1999, the IEEE 802.11a standard was developed. The standard specifies that the WLAN operating frequency band is 5.15 to 5.825 GHz, the data transmission rate reaches 54 Mbps/72 Mbps (Turbo), and the transmission distance is controlled at 10 to 100 meters. 802.11a adopts the unique spread spectrum technology of Orthogonal Frequency Division Multiplexing (OFDM); it can provide 25Mbps wireless ATM interface and 10Mbps Ethernet radio frame structure interface, and TDD/TDMA air interface; support voice, data, and image services. One sector can access multiple users, and each user can have multiple user terminals. In September 1999, IEEE 802.11b was officially approved. The standard specifies that the WLAN operating frequency band is 2.4 to 2.4835 GHz and the data transmission rate reaches 11 Mbps. This standard is a supplement to IEEE 802.11. It adopts two modes of operation: point-to-point mode and basic mode. In terms of data transmission rate, it can automatically switch between different rates of 11Mbps, 5.5Mbps, 2Mbps, and 1Mbps according to actual conditions, and at 2Mbps. Compatible with 802.11 at 1Mbps. 802.11b uses Direct Sequence DSSS as the protocol. 802.11b is not compatible with the 802.11a standard operating at 5 GHz. Due to their low price, 802.11b products have been widely put on the market and run in many practical workplaces. The IEEE 802.11e standard proposes improvements to the WLAN MAC layer protocol to support multimedia transmission to support the QoS mechanism of all WLAN radio broadcast interfaces. IEEE 802.11f, which defines communication between access nodes and supports IEEE 802.11 Access Point Interoperability Protocol (IAPP). IEEE 802.11h is used for spectrum management technology of 802.11a. The IEEE 802.11g standard speeds up the popular 802.11b (ie Wi-Fi standard) (the speed is increased from 11 Mb/s to 54 Mb/s for 802.11b). 802.11g access points support 802.11b and 802.11g client devices. Similarly, laptops with 802.11g NICs can access existing 802.11b access points and new 802.11g access points. However, products based on the 802.11g standard are still rare. If you need high speed, the already introduced 802.11a product can provide a maximum speed of 54Mb/s. The main disadvantage of 802.11a is that it cannot interoperate with 802.11b devices, and compared with 802.11b, 802.11a network cards are 50% more expensive and access points are 35% more expensive. The IEEE 802.11i standard combines user port authentication and device authentication in IEEE 802.1x to modify and integrate the WLAN MAC layer, and defines a strict encryption format and authentication mechanism to improve the security of the WLAN. The IEEE 802.11i new revised standard mainly includes two contents: "Wi-Fi Protected Access" (WPA) technology and "Strong Security Network". The Wi-Fi Alliance plans to adopt the 802.11i standard as the second version of WPA and began implementation in early 2004. In order to improve the throughput of the entire network, 802.11n optimizes the single MAC layer protocol of the 802.11 standard, changes the data frame structure, increases the proportion of the net load, and reduces the number of bytes occupied by the management error detection. The throughput of the network. The application of smart antenna technology also solves the transmission coverage problem of 802.11n. By adjusting the beam direction dynamically by an antenna array system composed of multiple independent antennas, 802.11n can ensure that users receive stable signals and reduce noise signals. Interference. In terms of compatibility, 802.11n uses software radio technology to solve the problem that different systems use different working frequency bands and different modulation methods, which are difficult to interwork and have poor mobility. Software radio is a programmable hardware platform. All applications are implemented by software programming on the platform. Base stations and mobile terminals of different systems can be implemented by different software based on the same hardware. Software radio technology enables wireless LANs to integrate with wireless WANs and accommodates a variety of standards and protocols, providing a more open interface. In addition, the 802.11n operating mode includes two operating frequency bands of 2.4 GHz and 5.8 GHz, which is compatible with the previous 802.11a/b/g standard, which greatly protects the user's investment. Wifi Bulb,Led Light Bulb,Led Flood Light Bulbs,Led Replacement Bulbs Shenzhen Chaoran Technology Corp. , https://www.chaoran-remote.com