WiMax, the Worldwide Interoperability for Microwave Access is a new technology dealing with provision of data over long distance using wireless communication method in many different ways. Based on IEEE 802.16 WiMax is claimed as an alternative broadband rather than cable and DSL. In our thesis study we will findout the phenomenon and factors involved in WiMax handover and their effect on overall quality of service. We also intend to look into the solutions possible for those problems effecting WiMax QoS in handover. Handover is the main theme of wireless technolgy and it makes interoperability between diffrent network technologies and provides mobility. However there are some problems during handover and the problem in our focus will be handover delay. Handover delay if longer than expected makes the communication faulty and introduces errors and packet loss which in turns degrade QoS in WiMax

The purpose of this thesis is to show up possibilities of inter-vehicle communication and to introduce new approaches in communication for the purpose of enhancing the security and the fluency of vehicle transportation. This thesis also highlights vulnerabilities in communication. The main goal is the analysis of existing technology and the design of protocol for data transfer with focus on minimizing handover time of informations. Part of the design is a simulation of communication based on acquired information.

High data rates and interoperability of vender devices have made WiMAX a prime desire for use worldwide. WiMAX is based on the IEEE 802.16 standard. IEEE 802.16a, b, c & d versions were updated within three years of the first launch of WiMAX. However, during those early years reports were published that highlighted the security weaknesses of the standard. These weaknesses prompted the IEEE to issue a new version, 802.16e to tackle the security issues. Despite this security enhancement, WiMAX remains vulnerable. This research project looks at the vulnerability of WiMAX 802.16e Subscriber Station/Mobile Station authentication at the initial entry and proposes approaches to the prevention of Denial of Service (DoS) attacks at this point in order to secure the Media Access Control (MAC) layer from such threats. A new protocol has been designed and developed to provide confidentiality, authentication and integrity to WiMAX users. This new protocol is integrated with Z algorithm (an algorithm described later in this paper) to provide: • Confidentiality of management messages • Message Authentication code • ID to provide for message integrity and user authentication. A simulation package was also required, to prove that a linear load of DoS attack would disable or exhaust the capacity of the base station of a WiMAX network, as well as providing other simulation functions. The freely available simulation tool NIST (NIST IPSec (Internet Protocol Security) and IKE (Internet Key Exchange) Simulation) is oriented towards fixed network communications (NIIST, 2003). There are no other relevant simulation tools; hence the purpose of this research project is to develop a new tool to simulate WiMAX security vulnerabilities and test the new protocol.