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Recently, considerable research effort has been put into the direction of integrating the broadband wired ATM [1] and wireless technologies. In 1996 the ATM Forum approved a study group devoted to wireless ATM, WATM. WATM [2–4] aims to provide end-to-end ATM connectivity between mobile and stationary nodes. WATM can be viewed as a solution for next-generation personal communication networks, or a wireless extension of the B-ISDN networks, which will support guaranteed QoS integrated data transmission. WATM will combine the advantages of freedom of movement of wireless networks with the statistical multiplexing (flexible bandwidth allocation) and QoS guarantees supported by traditional. | Wireless Networks. P. Nicopolitidis M. S. Obaidat G. I. Papadimitriou and A. S. Pomportsis Copyright 2003 John Wiley Sons Ltd. ISBN 0-470-84529-5 10 Wireless ATM and Ad Hoc Routing 10.1 Introduction Recently considerable research effort has been put into the direction of integrating the broadband wired ATM 1 and wireless technologies. In 1996 the ATM Forum approved a study group devoted to wireless ATM WATM. WATM 2-4 aims to provide end-to-end ATM connectivity between mobile and stationary nodes. WATM can be viewed as a solution for next-generation personal communication networks or a wireless extension of the B-ISDN networks which will support guaranteed QoS integrated data transmission. WATM will combine the advantages of freedom of movement of wireless networks with the statistical multiplexing flexible bandwidth allocation and QoS guarantees supported by traditional ATM networks. The latter properties which are needed in order to support multimedia applications over the wireless medium are not supported in conventional LANs due to the fact that these were created for asynchronous data traffic. 10.1.1 ATM In this section a brief introduction to ATM is made in order prior to discussing Wireless ATM. ATM also known as cell-relay for reasons that will be described later is a technology capable of carrying any kind of traffic ranging from circuit-switched voice to bursty data at very high speeds. ATM possesses the ability to offer negotiable QoS. Thus ATM is the technology of choice for multimedia networking applications that demand both large bandwidths and QoS guarantees since these properties cannot typically be offered by conventional networks such as Ethernet LANs. ATM is a packet-switching technology that somewhat resembles frame relay. However the main difference is the fact that ATM has minimal error and flow control capabilities in order to reduce control overhead and also that ATM utilizes fixed-size 53 bytes packets known as cells instead of .