Lately, Wireless Sensor Networks are getting lot of attention by research community. It consists of small devices distributed over geographical areas and each device has sensing, computing and communicating components. Time synchronization is vital to schedule communication and distributed measurement tasks. It targets at equalizing the local times for all nodes in the network. It has been obse...

NFS is a widely used remote le access protocol that has been tuned to perform well on traditional LANs which exhibit low error rates. Users migrating to mobile-hosts would like to continue to use NFS for remote le accesses. However, low bandwidth and high error-rates degrade performance on mobile-hosts using wireless links thus hindering the use of NFS. In this paper, we present two mechanisms ...

Wireless sensor networks (WSNs) comprised of low-cost devices tend to be unreliable, with failures a common phenomenon. Being able to accurately observe the network health status — of nodes of each type and links of each type — is essential to properly configure applications on WSN fabrics and to interpret the information collected from

Wireless Sensor Networks (WSNs) are composed of nodes that gather metrics such as temperature, pollution or pressure from events generated by external entities. Localization in WSNs is paramount, given that the collected metrics must be related to the place of occurrence. This work presents an alternative way towards localization in randomly deployed WSNs based on the combination of individual ...

As wireless services have become increasingly integrated and their demand is mounting, Wi-Fi provides an appealing opportunity for the GSM/GPRS operators to enhance their data capability. By integrating both networks, operators are able to provide 3G-like services. However, both networks have different data rates and capacity, which makes pricing a challenging issue. In this paper we propose a ...

Wireless nodes equipped with multiple radio interfaces open up new fields of application. Ranging from multi-channel usage in a cell in order to increase the bandwidth to the creation of meshed multi-hop topologies. Using multiple wireless cards demands a large physical space, more energy consumption and as a consequence decreasing in the battery lifetime. Virtualization of the wireless network...

This journal paper presents a measurement-based performance management system for contention-based wireless sensor networks. Its main features are admission and performance control based on measurement data from lightweight performance meters in the endpoints. Test results show that admission and performance control improve the predictability and level of performance. The system can also be use...

It is important to provide possibility of so called “handover” for the mobile subscriber from GSM network to Wi-Fi network and back. To solve specified problem it is necessary to estimate connection time between base station and wireless access point. Difficulty to estimate this parameter is that it doesn’t described in specifications of the standard and, hence, no recommended value is given. I...

Wireless Sensor Networks promised to do for observation systems what consumer electronics have done for areas like photography--drive down the price per observation (photograph), introduce new functionality and capabilities, and make, what had been a relatively exclusive set of technologies and capabilities, ubiquitous. While this may have been true for some terrestrial sensor networks there ar...