SWAN: a mobile multimedia wireless network
IEEE personal communications
SWAN (Seamless Wireless ATM Network) is an experimental indoor wireless network that investigates the combination of wireless access with multimedia networked computing in an indoor setting. It is based on room-sized pico-cells and mobile multimedia end-points. It enables users carrying multimedia end-points such as PDAs, laptops, and portable multimedia terminals, to seamlessly roam while accessing multimedia data resident in a backbone wired network. The network model of SWAN consists of
... tations connected by a wired ATM backbone network, and wireless ATM last-hops to the mobile hosts. SWAN is one of the first systems to realize the concept of a wireless and mobile ATM network. Mobile hosts as well as basestations are embedded with custom designed ATM adapter cards called FAWN (Flexible Adapter for Wireless Networking). FAWN uses off-the-shelf 2.4 GHz ISM band radios. After giving an overview of the SWAN network model, and discussing the challenges in making ATM wireless and mobile, the paper describes the first phase implementation of SWAN hardware and software. This initial implementation provides connectivity over the wireless last hop. We have investigated both native mode endto-end ATM communication across the wired ATM backbone and wireless ATM links, and TCP and UDP communication using IP-over-wireless-ATM in the wireless link with IP forwarding and segmentationreassembly modules at the basestations. The latter mode of communication has allowed experimentation with various readily available TCP and UDP based multimedia applications such as nv, vat etc. Typical TCP throughput is 227 Kb/s when the raw channel bandwidth being equally divided into 312 Kb/s each in the transmit and receive directions, while round-trip delays over the wireless hop range from 5 ms to 25 ms. Performance metrics such as throughput, delay and delay jitter are affected by various wireless link attributes. The paper presents experimental data that explores the relationship between performance and wireless link attributes such as the frame size used to transfer data over the air, and the number of mobiles that are sharing the link.