Networking (PACWOMAN Sub project 2)

The Networking activities are concerned with the algorithms of layer three that provide full connectivity to the different nodes that conform to the ad-hoc network. The ad-hoc network is expected to operate in dynamic environment in which some or all the nodes are mobile. The network functions must run on distributed platform, as nodes might suddenly disappear or show up in the network resulting in varying network topologies. Nevertheless the connectivity should stay undisrupted. The study of networking in a Wireless PAN context started with an investigation of the state-of-the-art and identification of open research issues. After this, based upon an analysis of the requirements and expectations concerning the improvement of technology, a total system concept has been designed. The mobile node will be able to access a fixed network (such as Internet) or services, even through several wireless hops removed from the network access points. The routing procedures maintain the connectivity among the nodes/services, despite the nodes? mobility. The routing is also responsible for inter-working between the ad-hoc and fixed networks. The Wireless Personal Area Network (WPAN) infrastructure with ad-hoc connectivity addresses the problem of Quality of Service (QoS) support for different applications (defined for UMTS), such as conventional (voice), streaming (video/audio), interactive (WEB), background (FTP). The routing protocols should support the mobility patterns and QoS classes and should be able to operate without the support of fixed (wireless and wired) infrastructure. They must consider typical limitations of the ad-hoc networks, such as higher bandwidth consumption and hostile wireless environment. They must also be power-constraint, keeping in mind that most of the involved nodes are mobile. From the PACWOMAN perspective the protocol design should offer the solution for: 1. Dynamic topologies; 2. Bandwidth constraint and variable capacity links; 3. Power-constraint operation; 4. QoS support; 5. Localization and capability and service based address management; 6. Mobility modelling; 7. Distributed traffic modelling; 8. Cross-layer protocol optimization. The analysis focussed in this first phase of the research on the evaluation of existing ad-hoc routing protocols in the context of the PACWOMAN Architecture. DSR, DSDV, AODV and TORA have been considered. The second phase of the research will focus on an extension of these protocols towards a cluster-based approach. To evaluate the communication between PAN/CAN with the proposed innovation regarding the Networking (clustering algorithms, power-aware routing) and investigate the feasibility and performance of the existing two categories of routing protocols, simulation studies are being carried out with the NS2, Network Simulator from Berkeley University. By using data with different communication characteristics we tested the suitability of the ad-hoc routing algorithms in the envisioned architecture. In this work package also the interaction between the network layer and link layer will be taken into account, masking the physical link for the network layer and optimising parameters like applied coding, retransmission schemes and packet size. (Carl Wijting, Yaoda Liu, Istvan Kovacs, Liljana Gavrilovska, Efrayim Metin)