The Research And Application Of Wireless Lan Based On IEEE 802.11b

The wireless LAN(WLAN) is the combination product of computer network and wireless communication technology in the 1990's, it provides the access to network via wireless channel. WLAN has the installation convenience, the mobility and the high speed etc, which has got widely deployed in many fields. In this thesis the protocol and architecture of the IEEE 802. lib WLAN are studied, the "railway container station MIS" is developed and a safety communication solution for this MIS is proposed.Physical layer and MAC (Medium Access Control) layer in IEEE 802.11 b are summarized. Two MAC layer access methods: DCF (Distributed Control Function) and PCF (Point Control Function) are deeply analyzed. MAC service, the CSMA/CA protocol and the RTS/CTS mechanism are generally narrated.In the development of the "railway container station MIS", aimed at the different station geography circumstance, we bring up the homologous wireless access network scheme respectively. Because the mobile device?Pocket PC is adopted as the client in the project, for realizing information management based on Windows embedded operation system, two-tier model and three-tier model of MIS are analyzed detailedly. ASP technique, embedded programming technique and mobile database technique are applied to the project development. Under B/S and C/S/S two kinds of development pattern, the main system function is accomplished in the PDT 8146 of Symbol Company.With the rapid growth of WLAN, which has brought about more security requirements in WLAN. The basic security mechanism and the security weakness of WLAN are analyzed in the thesis. A safety solution which is applied to the "railway container station MIS" is Put forward. In the solution, TKIP encryption, IEEE 802.1x bidirectional authentication and MAC address access control are adopted for protecting system communication safety.