Based On The Ieee802.11 Wireless Lan Technology

The goal of the modern communication is the realization of personal communication, which means that anyone can exchange any kind of information with whoever he want to contact anywhere at any time. So the mobility and the high speed are key techniques of the communication system. Among current mobile communication systems, only the WLAN supports the mobility and high speed so it must be an important part of the mobile communication system in the future.Some techniques of IEEE802.il WLAN will be studied in the dissertation, and the research includes:1.Introduced the development of current wireless data communications. 2.Expatiated on the constitutions and techniques of WLAN. 3 .analyzed the performances and characteristics of several stochastically competitive MAC protocols; then discussed the MAC protocol appliedin WLAN--CSMA/CA and at last made some simulation on thethroughputs of all MAC protocols discussed here. 4.Analyzed two types of spread spectrum(DSSS and FHSS) approved by the FCC based on the characteristic of PHY layer; then analyzed the characteristic and technology of the CCK modulation and at last put forward an improved CCK scheme that will increase the data rate of WLAN to 16.5Mbps. 5.Discussed the design of a WLAN card.At the end of the dissertation we made some advises for the future work and anticipate the development of the WLAN in the future.