Wireless Campus Network Construction Scheme

In terms of application requirements, wireless networks are suitable for some campus applications that are not easy to use for network cabling. Currently, most campuses have wired LAN. How can we further expand the original network so that every corner of the campus is on the network to form a campus network in the true sense? This article describes how to use the wireless LAN technology to build a campus network.

　　Wireless Network Infrastructure

Wireless Local Area Network (WLAN) technology includes Bluetooth, IEEE 802.11 series, HiperLAN, and HomeRF technologies. The IEEE 802.11 series is widely used. IEEE 802.11b supports 11 Mbps shared access speed and adopts the 2.4 GHz ISM band. Similar to IEEE 802.11a technology, it adopts the 5 GHz band and achieves a high speed of 54 Mbps; last year, the new IEEE 802.11g is actually a hybrid standard. It can adapt to the IEEE 802.11b standard and comply with the IEEE 802.11a standard, but it is not very mature yet. In the current situation, both the transmission distance and transmission rate of IEEE 802.11b have an advantage. Therefore, the IEEE 802.11b standard can be used for wireless campus networks.

A wireless LAN consists of a wireless network card and an Access Point (AP ). A wireless LAN uses a conventional LAN (such as 10/100/M Ethernet) and its interconnected devices (routers and switches) to form a backbone network. The Wireless Access Point (AP) is used to support mobile terminal (MT) movement and roaming. A desktop PC, laptop, or other device with a wireless network card can be connected to a wireless network.

For clients, the wireless network card is used as the wireless network interface to connect to the wireless network. There are three main types of wireless network adapters based on different interface types: PCMCIA wireless network adapter (applicable to laptops and supports hot swapping) and PCI wireless network adapter (applicable to desktops) and USB wireless NICs (applicable to Laptops and Desktops, hot swapping is supported ).

A wireless access point is used to bridge between a WLAN and a LAN. WLAN workstations can also be Roaming between different APs. Without an external antenna, the AP coverage is theoretically about 250 m in the field of view. However, if it is in a semi-open space or an area with an interval, it is about 30 ~ About 50 MB. Because the microwave is a linear transmission, the microwave is a small angle to penetrate several sides of the wall, the wall will weaken the signal, if the wall is reinforced concrete, the signal will be weaker. Therefore, in actual situations (usually outside), an external gain antenna must be added to make the distance farther and the signal stronger.

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