WSNs being energy constrained systems, one major problem is to employ the sensor nodes in such a manner so as to ensure maximum coverage and connectivity with minimal or optimal number of nodes and furthermore elongate network lifetime with maximum e

X-MAC, a low power MAC protocol for wireless sensor networks (WSNs). Standard MAC protocols developed for duty-cycled WSNs such as BMAC, which is the default MAC protocol for TinyOS, employ an extended preamble and preamble sampling.

one destination.he channel capacity between the source and the relay is usually different from that between the relay and destination because of the independent fading on the two links. The network capacity for each channel realisation is constrained

WiMAX (acronyme pour Worldwide Interoperability for Microwave Access) désigne un standard de communication sans fil. Aujourd hui surtout utilisé comme mode de transmission et d accès à Internet haut débit, portant sur une zone géographique étendue. C