TCP Performance in Ad Hoc Networks

Ad hoc networks are mobile wireless networks which do not have any kind of fixed infrastructure. The routing layer in an ad hoc network ties the network together into a seamless entity and provide transparent services to higher layer protocols. This thesis examines the interactions of two routing protocols, AODV and DSR and how the mobile ad hoc network environment affect TCP performance. The results presented here are as follows: the path length and the presence of competing traffic are the main factors of TCP throughput performance. The size of TCP window affects the loss rate, but the loss rate is not strongly correlated to throughput performance. Using TCP selective acknowledgement option does not improve throughput. Finally, there is hardly any difference in TCP throughput when using DSR and AODV. These conclusions are supported by extensive simulation experiments

TCP Performance in Ad Hoc Networks

Ad hoc networks are mobile wireless networks which do not have any kind of fixed infrastructure. The routing layer in an ad hoc network ties the network together into a seamless entity and provide transparent services to higher layer protocols. This thesis examines the interactions of two routing protocols, AODV and DSR and how the mobile ad hoc network environment affect TCP performance. The results presented here are as follows: the path length and the presence of competing traffic are the main factors of TCP throughput performance. The size of TCP window affects the loss rate, but the loss rate is not strongly correlated to throughput performance. Using TCP selective acknowledgement option does not improve throughput. Finally, there is hardly any difference in TCP throughput when using DSR and AODV. These conclusions are supported by extensive simulation experiments

Issues of Spontaneous Collaboration and Mobility

Spontaneous collaboration occurs abundantly among people on the roads. We account for the outcome of three research projects and the experience of designing the applications: Placememo, Hocman and SoundPryer. They all support various types of spontaneous mobile collaborative road use activities. We emphasize the impact of setting when developing applications intended for this scope. The main issues considered concern: simultaneous activities, mobility, information composition and sharing

Sound Pryer Field Trials: Learning About Adding Value to Driving. Presented at the workshop Designing for ubicomp in the wild: Methods for exploring the design of mobile and ubiquitous services, at MUM’2003

Sound Pryer augments traffic encounters with streaming audio. It is a collaborative car stereo allowing sharing brief and transient musical experiences among drivers. It is a peer-to-peer application for PDAs capable of wireless ad-hoc networking. We have identified seven issues concerning, studying entertaining mobile applications, the control of and the spontaneity of traffic encounters, driver’s safety, user’s privacy, technical support and copyright, when evaluating it with unacquainted drivers in traffic. We argue that field trials allow us to obtain rich holistic data on usage yet overcoming them. We demonstrate a manageable and realistic procedure also appropriate for other mobile collaborative applications and services. Keywords Field trials, wireless ad hoc networking, traffic encounters, streaming audio 1

Adding value to traffic encounters: A design rationale for mobile ad hoc computing services

The roads are places where an extensive amount of everyday meetings among people occur. Two issues make the social interaction meagre. First, when driving, high speed makes these encounters brief. Second, driving often involves being enclosed by a hull of a vehicle. Consequently, this interaction and, in the end, also driving, occasionally becomes tedious. We suggest a design rationale for mobile ad hoc computing services that add value to traffic encounters, yet taking into account safety issues. We argue such services would considerably augment and enrich the highway experience. This rationale, which honours the main features of the prevalent social interaction, is motivated by two prototype services: Hocman and Sound Pryer. The first adds value to biking activities. The latter provides shared music listening experiences during traffic encounters. Keywords: Design Rationale, Traffic Encounters, Mobile Ad hoc Computing.