Issues in IP-based cellular networks

Since their introduction, cellular networks have constantly upgraded their air interface to keep pace with developments in wireless communications. However, the wired infrastructure part of the cellular network has remained relatively unchanged. This restricted the ability of cellular networks to take advantage of developments in the wired world including the rapid growth of the Internet.; In this dissertation, a new generation of cellular networks is proposed that are designed as an extension to the Internet. These IP based cellular networks can leverage various IP network technologies to achieve significant cost benefits besides having an open service creation environment that can enable new mobile services and applications. Some technical issues in this context are studied.; The use of Voice-over-IP technology in cellular networks is discussed. A review of literature showed that VoIP over cellular networks can provide good voice quality and efficient use of bandwidth despite the high delay on cellular networks and Internet and the large header overhead in VoIP.; The importance of handoffs and mobility management in current and future cellular networks is discussed. Several IP mobility solutions were proposed in the literature. Their performance is evaluated and it is shown that they are not suitable for operation on IP based cellular networks. A new mobility management protocol is proposed that can handle fast and frequent handoffs with no extra overhead. The performance of this protocol is evaluated and it is shown that it can achieve good performance on IP based cellular networks.; The issue of macrodiversity in IP based cellular networks is studied. Macrodiversity increases the capacity and coverage of CDMA based cellular networks. It is exploited in current cellular networks through a technique called soft handoffs. An examination of the use of soft handoffs in IP based cellular networks found that it suffers from many disadvantages and is not very useful. A new method to exploit macrodiversity in IP based cellular networks is proposed and its performance is evaluated through simulations. Using cell coverage as the metric, it is shown that this method achieves macrodiversity gains close to those achieved by soft handoffs without suffering the disadvantages of soft handoffs in IP based cellular networks.; In the second part of the dissertation, handoff transients in wireless ATM networks are studied. The Virtual Connection Tree concept had been proposed to handle fast handoffs in wireless ATM networks. A simple protocol designed to prevent packet loss and preserve packet sequence during handoffs is proposed and analysed. The delay transients that occur during handoffs with this protocol are studied.