Sharif Digital Repository

Many performance evaluations for the IEEE 802.11 Distributed Coordination Function (DCF) have been previously reported in the literature; most studies are based on saturation analysis, and a few models under a finite-load condition adopt an M/G/1 queuing system. However, using M/G/1 queuing only considers the first moment of the frame service time to derive the probability of the transmission queue being vacant. In this paper, we model the DCF using the parallel space-time Markov chain, where the frame arrivals are tracked by monitoring the transmission queue during transitions between successive states of the space-time Markov chain. The proposed framework provides the possibility of... 

Sensor networks are systems of many small units that work together to monitor a given environment. A mixed sensor network is composed of a collection of static and mobile nodes that has sensing, computation, communication, and locomotion capabilities. Sensor mobility can be used to compensate for the lack of sensors and improve network coverage. This paper aims to describe an algorithm called Coin for mixed sensor network deployment in an unknown environment by using a small number of mobile sensors. It allows the network to achieve maximum coverage with minimum energy consumption. Our solution includes distributed schemes for: 1) determining the exact size of a coverage hole; 2) determining...