Application of wireless local area network

To explore the application of wireless LAN, we should first analyze the technical characteristics of WLAN, because it is the technical characteristics of WLAN that determines the application range of WLAN. By comparing the wireless LAN with the cellular Mobile communication Network (GPRS and 3G of 2.5 generation), we can find the application location of WLAN.

First of all, from the working band, the frequency of cellular mobile communication network needs to be licensed, pay fees, strict government control. The working band of Wireless LAN is another situation.

802.11B work for the 2.4GHz ISM band for the internationally universal license-free band. In China, the Ministry of Information Industry in 2001 issued a letter of no [2001]653 notice, clear in 2400~2483.5mhz this 83.5MHz band, indoor WLAN can be used without approval.

802.11a work in the 5GHz band in the United States for the U-nii band, is also a license-free band. In our country the situation is different. July 2002 Ministry of Information Industry issued a letter without [2002]277 notice, clear in 5725~5850mhz this 125MHz band, high-speed wireless LAN and point-to-point or point-to-point spread spectrum communication system, broadband wireless access system, Bluetooth technology equipment and vehicle wireless automatic identification system, such as radio stations share this frequency band. Set up to use the 5.8GHz band radio transmitter station, must report to the province, autonomous region, the central municipality Radio Management Authority approval. Outdoor Wireless LAN is required to receive a radio license. At the same time 5725~5850mhz this frequency band in principle for the public network wireless access communication, the operation Enterprise must obtain the corresponding basic telecommunication business Operation license.

Compared with the 2.4GHz band and 5.8GHz band in our country these policies, 2.4GHz band with its license-free will be in the future for a long time by enterprises, households and other users widely used. And 5.8GHz band, with the maturity of 802.11a equipment and the expansion of market size, I believe that in the next two years the basic telecommunications operators will start this band of 802.11A Wireless LAN construction.

In terms of coverage, wireless LANs usually cover distances ranging from dozens of m to hundred meters. Therefore, wireless LAN is more suitable for small coverage, covering the airport, coffee shops, office buildings and other so-called "hot" areas, but not suitable for the continuous wide-area coverage across the city. and cellular mobile communication network can be global coverage. (Computer science)

From the data rate, wireless LAN can provide the rate of 11mbps~54mbps, which is much higher than the data rate GPRS can provide, but also higher than the 3G mobile network support data rate. From this point of view, Wireless LAN has the advantage of high data rate, suitable for the application of high data rate requirements.

WLAN is currently mainly to provide data applications (such as Internet access, enterprise network access, etc.). Similar to its function, there are wired networks (such as Wired LANs) and cellular data networks. Comparing their differences, we can analyze the application and development prospects of WLAN. Compared with the wired network, WLAN has no advantage in access bandwidth and network reliability, but the portability of WLAN, ease of installation makes WLAN very suitable for a variety of reasons not easy to install wired network, such as protected buildings, airports, or often need to change the wiring structure of places, such as exhibition hall, etc. , the portability of the same WLAN support makes it ideal for fast-moving data services for users with portable devices such as laptops or PDAs in areas of mobile office, such as hotels, office buildings and airports.

WLAN is less portable than cellular data network, but its access bandwidth is much higher, WLAN is suitable for data users such as mobile business office with high bandwidth requirement, and cellular data network can only provide service to data users with low access bandwidth requirements.

From the actual application scenario of WLAN, there are now roughly two types:

One is the enterprise's own set up for enterprise internal users of the WLAN network to replace the enterprise cable network or as a complementary cable network. For example, a large supermarket, through the WLAN network, can be in the supermarket any counter, through the handheld terminals, statistical inventory, to the central system to deal with, you can quickly and efficiently grasp the sales situation, timely purchase. This kind of application can obviously improve the informatization degree of enterprise and promote the development of enterprises. With the attention of enterprise to informatization, this kind of application will be developed rapidly.

The other is the wireless ISP in such as office buildings, guesthouses, airports and other so-called "hot spots" area, the construction of WLAN network, to the public mobile data users to provide Internet access services, and to charge users with network access fees. Such WLAN networks are generally more decentralized and independent. In order to build a telecom-grade WLAN network which can be operated and widely roaming, it is necessary to solve such problems as authentication and billing.

There are two main technologies currently in the process of solution: one is based on the scheme of SIM card, based on the successful roaming scheme of GSM and CDMA network, it is suitable for operators with GSM or CDMA network, and the other is based on user name/password scheme, based on the successful application of RADIUS protocol on Internet, Can be extended to the characteristics of WLAN, this scheme is more suitable for operators with ISP operating experience. The reliability and stability of these two schemes need to be tested in the actual operation. With the development of Internet, the rapid popularization of mobile office and mobile commerce, this kind of application of WLAN has great market potential and development opportunity.

At present, the domestic telecom operators to the "hotspot" area of WLAN applications to give a high degree of concern. China Netcom is the first WLAN access service provider in our country. China Netcom has opened a wireless LAN access service known as the "Unlimited Companion Brigade" (Mobile Office) in business hotspots in cities including Shanghai, Shenzhen, Guangzhou and Beijing. China Telecom also in Shanghai, Guangdong and other fields have opened the "Tianyi" service, in cafes, hotels, terminals, conference centers, exhibition halls, stadiums and other services to provide WLAN access.

And China Mobile is in the fierce competition environment, according to its own comparative advantage, plan to launch "Gprs+wlan" Wireless data business bundle scheme in this year. Users in hot spots through the wireless LAN to achieve up to 11Mbps of high-speed access, in areas not covered by WLAN, automatic transfer to China Mobile GPRS network access to mobile Internet, and to achieve the user in the network roaming identity of the unified authentication and user bills and other services. "Gprs+wlan" of the bundle, will promote the coordinated development of WLAN and GPRS, promote the popularization and popularization of mobile data service, so as to some extent also in the introduction of the 3G business exploration.

Conclusion

With the development of wireless LAN technology and products, the wireless LAN will be used more and more widely with the increasing demand for access to the Internet or corporate network. Due to the participation of telecom operators, wireless LAN will gradually from high-end business to the general consumer development. Wireless LAN will play an important role in the process of social informatization.