Performance Evaluation of Wireless Networks

Wireless technologies are without any doubt shaping the beginning of the new millennium. Cellular networks (2/2.5/3 Generations) have reached global coverage and wireless LANs are providing high speed internet access to city centres and hot spot areas. The principle of computing anytime anywhere is becoming reality. Consequently, there has been tremendous interest recently in the convergence of wired (fixed) networks and mobile wireless and local wireless access systems and networks. B3G and 4G concepts have been the very hot subject of much research and many standardization activities throughout the world. Many B3G/4G related technical committees are taking the initiative to produce enhanced proposals of radio transmission technologies, wireless applications protocols, All-IP wireless network architectures, super signal processing and advanced system prototypes for B3Gwireless and 4Gmobile. However, there are several performance issues that need to be addressed and resolved before a global and widescale integrated broadband infrastructure of convergent multi-service networks can be established towards the next generation Internet with efficient support of multimedia applications. This special issue presents the best six papers from the first workshop on Performance Modelling of Wired and Wireless Mobile Computing and Networks held in conjunction with the 11th ICPADS 2005, Fukuoka, Japan. These papers were selected by the scientific programme committee and extended and revised before undergoing a rigorous period of peer-review. The purpose of this workshop was to provide an international forum for researchers and industry practitioners to present their state-of-art research on performance modelling and evaluation studies in all aspects of wired and wireless networking and computing and to exchange ideas and explore new avenues of collaborations. This workshop attracted a large number of quality papers and the presentations generated very interesting discussions. This special issue comprises of six papers covering experimental studies, analytical modelling, simulation studies, traffic modelling and applications for challenging issues such as routing mechanisms, mobility management, traffic modelling, etc in wireless networks. Pong et al. investigated the relationship between the cell capacity and the station mobility pattern. They chose the most popular and widely implemented Random Waypoint Mobility model for the analysis. They presented an analytical model to study the effect of the Waypoint model on the achievable throughput of a cell and the variability in the channel demand. It was found that the throughput could be over-estimated if the cell coverage was comparable in size to the mobility region, but this effect diminishes as the mobility region becomes relatively larger. They illustrated this effect quantitatively with IEEE 802.11 WLANs as an example. Seah et al. reported an experimental study on the performance of interconnected MANETs running two different routing protocols, namely, the Ad hoc On-Demand Distance Vector (AODV) and Optimized Link State Routing (OLSR) protocols, and showed that with the use of multiple gateways, it is possible to viably interconnect multiple networks running different MANET routing protocols. They validated their experimental study against simulation and presented the credibility of their proposed scheme in large networks. Yassein et al. in their paper carried out a detailed investigation to see the effects of key system parameters in a typical MANET, including node speed, pause time, traffic load, and node density on the performance of probabilistic flooding. In this paper they claimed that the probabilistic flooding, being one of the earliest techniques, has not been considered for broadcasting in MANETs. Their results reveal that most of these parameters have a critical impact on the reachability and the number of International Journal of Wireless Information Networks, Vol. 13, No. 2, April 2006 ( 2006) DOI: 10.1007/s10776-006-0026-1