Performance analysis of ad hoc wireless LANs for real-time traffic

Integration of a speech activated control system and a wireless interworking unit for a CAN-based distributed application

“…The IEEE 802.11 WLAN IEEE 802.11 WLAN, employing carrier sense multiple access/ collision avoidance (CSMA/CA) as the channel access method and operating in the 2.4 GHz unlicensed ISM (Industrial, Scientific and Medical) band, is a local area network implemented without wires. The main advantages of WLAN are the mobility and costsaving installation in addition to all the features and benefits of traditional LAN technologies (Aad and Castelluccia, 2003;Eshghi and Elhakeem, 2003;IEEE, 1999;Lindgren et al, 2003;Varshney, 2003). Its physical layer consists of two sublayers, namely physical layer convergence procedure (PLCP) and physical medium dependent (PMD).…”

“…The IEEE 802.11 wireless network currently possesses many features needed in an industrial automation environment, which is easy integration with other networking systems (FieldBuses) and capability to ensure critical time constraints of real-time data traffics (Aad and Castelluccia, 2003;Eshghi and Elhakeem, 2003;IEEE, 1999;Lindgren et al, 2003;Varshney, 2003).…”

An efficient broadcast relay scheme for MANETs

“…In the Medium Access Control (MAC) layer, mobile hosts share a single common channel using a simplified version of IEEE 802.11 Distributed Coordination Function (DCF) [17] without RTS/CTS, which applies Frequency Hopping Spread Spectrum (FHSS) parameters [18]. Moreover, acknowledgement (ACK) packets are used to combat collisions and high error rate in ad hoc networks.…”

Performance analysis of service differentiation in wireless local area networks with Poisson frame arrivals

“…One drawback to a saturated traffic model is that it can not provide us insight into system performance under unsaturated traffic conditions. Eshghi and Elhakeem (2003) proposed another novel mathematical model, where a more realistic Poisson frame arrival process is considered. However, it is also limited by assuming that all of the stations will increase their backoff stages or contention windows by a first factor once a collision is detected, and decrease their backoff stages by a second factor once the frame transmission is complete.…”

“…It is noted, instead of assuming a saturated traffic load as in (Bianchi, 2000), the method in (Eshghi and Elhakeem, 2003) is adopted to incorporate the Poisson frame arrival process. However, unlike assuming that each station can be characterized by an M/M/1/K as in (Eshghi and Elhakeem, 2003), we model each station as an M/G/1/K, since the frame transmission time distribution obviously is not memoryless. Specifically, a multi-dimensional discrete time Markov chain and an M/G/1/K together are used to describe the considered system.…”