Implementation and Evaluation of IEEE 802.11e Wireless LAN in GloMoSim

IEEE 802.11 Wireless Local Area Network (WLAN) is one of the most widely deployed wireless network technologies in the world today. The success of IEEE 802.11 mainly owes to its cost effectiveness, easy deployment and high data transmission rates. However, 802.11 MAC (Medium Access Control) algorithm is unable to support modern multimedia applications which require certain level of quality of service (QoS) guarantees in terms of consistent, in time and reliable data transfer. This lack of QoS support is a big hurdle in the evolution of multimedia applications over IEEE 802.11 networks. Therefore, enabling QoS support in the IEEE 802.11 networks has been the focus of research activities for some time. The IEEE 802.11 Working Group is currently working on an enhanced version of the 802.11, known as 802.11e, to provide support for QoS. The access mechanism of 802.11e, referred to as Enhanced Distributed Channel Access (EDCA), assigns different types of data traffic with different priorities based on the QoS requirements of the traffic, and for each priority, uses a different set of medium access parameters to introduce QoS support. This thesis presents the implementation of IEEE 802.11e EDCA simulation model in GloMoSim (Global Mobile Information System Simulator), which is a popular simulation software for wireless networks. Next it presents the performance evaluation of IEEE 802.11e EDCA with the help of a wide range of simulation scenarios in GloMoSim. The evaluation also includes the study of the role of different parameters IEEE 802.11e EDCA utilizes to realize service differentiation as well as the performance comparison of 802.11 and 802.11e. The evaluation results depict that IEEE 802.11e introduces an effective and optimal mechanism to provide QoS support based on the requirements of traffic and thereby significantly improves the overall network performance.