The Research On Protocol Of 802.11n & Implementation Of Wireless Access Point Function

This paper introduced the development of wireless local area network and its topology structure. Wireless local area network consists of wireless stations, wireless access point and computers. Wireless access point is the pivotal device of wireless local area network, which provides services for wireless stations and connects the wireless stations to cable network, with the function equal to switcher. 802.11n standard is the next-generation protocol of wireless local area network. It works in the higher transport speed and more covered area compatible to 802.11a/b/g.This paper analysed and researched the key techniques of media access control layer and physical layer of 802.11n standard. Its physical layer adopts modulation and coding scheme, which combines multiple-input multiple-output technology and orthorgonal frequency division multiplexing technology, 40MHz bandwidth and physical layer frame-aggregation. Its media access control layer adopts techniques of data packet-aggregation and optimization of access control.This paper used DWA-542 PCI interface to build hardware environment of access point of wirless local network. DWA-542 is produced by D-Link corporation supporting 802.11n standard. The main difference between wireless access point and wireless station is the implementation of media access control protocol stack. Based on the driver program of wireless station of DWA-542, this paper added three modules supporting wireless access point function. The three moudles are creation of wireless local area network, management of wireless station admission and configuration of wireless local network. The design and implementation of three modules mentioned above were described in detail in the paper.Wireless access point of 802.11n standard is compatible to 802.11b/g standard. The developer can configure DWA-542 to work only under wireless access point of 802.11g standard. The aim of 802.11n standard is to provide high throughput. In order to measure its high throughput, the paper used test software(IXChariot) of network to test throughput of wireless access point of 802.11n standard. Meanwhile, the developer can configure DWA-542 to work under wireless access point of 802.11g standard, uses IXChariot to test throughput of wireless access point of 802.11g standard.By testing the throughput of wireless access point of 802.11n standard, this paper has been proved to achieve high throughput of wireless access point of 802.11n standard.