In Wireless Ad Hoc Networks, synchronization is a prerequisite to many basic operations such as frequency hopping, power saving, free contention channel access, clustering and security. Clock synchronization requires the availability of a common time reference for all mobile nodes. However, a synchronization algorithm cannot converge quickly to a stable point without considering the effects of collisions and channel interference inherent to wireless environments. In this paper, we propose a Fast Synchronization Protocol with Collision Handling for multi hop wireless ad hoc networks.

Context-awareness has gained an increasing popularity in ubiquitous computing environments as it allows automatic adaptation of protocols behavior according to context changes. Nowadays, wireless sensor networks (WSNs), deployed as a main appliance to gather contextual information, can benefit from their own context data. In such scarce resource networks, the concept of context-awareness can be exploited either to optimize resource usage or to enhance the functional behavior of operating protocols.

In Vehicular Ad-hoc Networks (VANETs), any vehicle uses a location service to get an up-to-date data of all vehicles’ positions in its vicinity. Many location services rely on infrastructures to perform location update and location query tasks. However, the infrastructure penetration rate may differ from one region to another. We propose in this paper a new location service called Vehicle-Aided Location Service in urban environment (VALS) which resolves the problem of the shortage of infrastructure in some city districts.

This paper deals with conflict detection for Unmanned Aerial Vehicles (UAVs). We provide an exhaustive mathematical framework for 3D conflict detection and propose a novel distributed conflict detection algorithm. The suggested algorithm requires minimal communication. Indeed, only the state information (i.e., position and velocity vectors) is periodically exchanged between the UAVs. We carry out simulations, using the OMNET++ simulator, to evaluate its performance.