There are two principal wireless LAN standards: IEEE 802.11 and ETSI HIPERLAN, which define the specification of physical and media access control layer. WLAN medium access control protocols describe the rules for orderly access to the shared wireless medium and play a crucial role in the efficient and fair sharing of scarce wireless bandwidth resource. IEEE 802.11 MAC layer employs CSMA/CA protocol to access medium, whereas ETSI HIPERLAN uses EY-NPMA protocol to control the medium access. In this thesis, the two standards are introduced first. Then, the simulation models are presented for various network architectures and environmental parameters in order to obtain comparable performance results regarding the buffer size, the packet lifetime period and the traffic load of terminal stations. After that, the simulation results are presented for different simulation models with analyzing and evaluating the performance for both standards in different criteria and various input parameters
