IEEE 802.11e QoS Enhancements for Efficient Internetworking with UMTS

Abstract

The goal of the next-generation access network is to offer users the capability of achieving anywhere and anytime network access with high data rate. Instead of developing the existing UMTS network using different methods (like cell sectoring, reducing the cell size, etc), the evolvement trend is to internetwork different access networks. However, Internetworking between WLAN and cellular in general, and IEEE802.11e and UMTS in particular, is a big challenge in the development of fourth generation wireless networks. This internetworking is useful to enhance the network operation, and reduce installation cost. UMTS cannot be replaced by WLAN but these two networks can be used to compensate some limitations on them. For instance, WLAN cannot cover wide areas as UMTS, but it can provide high-speed communication with low cost of installation. There are many aspects involved in this internetworking, such as mobility management, security support, and quality of service (QoS) provisioning. This thesis concentrates on the third aspect which is QoS and especially packet level QoS. The UMTS provides better QoS than IEEE802.11e especially for real time applications like voice. However, the goal is to unify the QoS provided by UMTS and IEEE802.11e. This goal can be met after studying the UMTS QoS and map it in the IEEE802.11e. Thus, this thesis proposes a new method to enhance the QoS of IEEE 802.11e especially for real time applications which is buffering method. This method introduces a modification in EDCF protocol based on setting a fixed time limit after which all packets that exceed it are dropped. Buffering method can be realized by add buffers at the station side and the AP side. Buffering method will be measured using an analytical tool based on Markov chains. In this thesis, we will develop a three dimensional MC that describes the station state. This MC is an enhanced one from an existence two dimensional MC. This thesis follows six phases to enhance IEEE 802.11e QoS and map UMTS QoS in IEEE 802.11e which are: First phase, studying the QoS in UMTS. Second phase, investigate IEEE 802.11e capability. Third phase, studying the main internetworking challenges. Fourth phase, propose a method to enhance IEEE 802.11e QoS. Fifth phase, propose an analytical model to measure the buffering method. Sixth method, presentation and discussion of the results.