Improving The Performance Of The WLAN Network

With the development of the Wireless Local Area Network (WLAN), a growing number of "hot spots" called AP access the WLANnetwork.However, because of the limited radio frequency, the interference between devices become more and more serious, which leads a great impact on the throughput of network. To solve this problem, binding and switching of bandwidth is described in 802.11n draft. The principle is:two channels of 20MHz bandwidth is bound into a 40MHz one in order to provide WLAN services for one AP. When the environment of the network is no longer fit for the bound channel with 40MHz,bandwidth switching happens.with only a 20MHz channel work for the AP. Now,the draft of 802.11n has become as standard, all manufacturers trying to improve competitiveness by upgrading their WLAN equipment has become a trend.With the 802.11n standard and the demand of the market as backgrounds,the main purpose of the article is to optimize the performance of the WLAN network by using the crucial technologies of 802.lln standard,such as:the bandwidth binding and the bandwidth switching between 20MHz and 40MHz.Ultimately,the work is started from the points of the initial channel allocation and bandwidth switching to make the performance of the WLAN network optimized.Specifically, this paper focuses on the following issues:Firstly, several basic knowledge of WLAN networks is briefly described in this paper.Secondly, the scanning technology in H3C WLAN system related to the channel allocation and bandwidth switch, channel allocation in fixed mode and channel assignment in auto-mode are introduced respectively,especially the channel selection for the AP with bandwidth of 20MHz in 802.11n.Thirdly, with the definition of OBSS Scan in 802.11n standard, the existing method of channel selection in 802.11n AP which is configured as auto mode with bandwidth in 20MHz is improved to achieve the channel selection for the AP whoes bandwidth is configured 40MHz, then achieve the bandwidth binding according to the principles of 802.11n standard.Finally, after the channel of AP in the 40MHz-bandwidth mode being selecting, the methods of detecting and proccessing switching events are designed in order to achieve the bandwidth switching. In addition, the test environment is built in H3C WLAN laboratory to test and verify the qualities which are described in the fomer part of this paper.