Michael D. Logothetis

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We study the problem of load balancing in 802.11-based wireless networks, operating in infrastructure mode. In a large wireless network with multiple collocated Access Points (AP), a load balancing policy is necessary for the distribution of the wireless stations (WS) to the AP’s, so as the network performance to be maximized. Already proposed algorithms,(More)
The IEEE 802.11 protocol is the dominating standard for Wireless Local Area Networks (WLANs) and has generated much interest in the investigation and improvement of its performance. The IEEE 802.11 Medium Access Control (MAC) is mainly based on the Distributed Coordination Function (DCF) with two access mechanisms: Basic and Request To Send/Clear To Send(More)
We investigate the performance of the IEEE 802.11e while emphasizing on the end-to-end delay performance. In our MAC delay analysis, we are based on elementary conditional probabilities, avoiding the complex Markov Chains method. For a thoroughly study of the MAC delay, we take the Z-transform of the backoff duration in order to provide higher moments of(More)
Optical access systems are now considered a feasible alternative to the predominant broadband access technologies, while, at the same time, passive optical networks (PONs) are viewed as an attractive and promising type of fiber access system. In this paper we present and analyze three basic dynamic wavelength allocation scenarios for a hybrid wavelength(More)
In this paper, we investigate the call blocking probability calculations in the uplink of W-CDMA mobile cellular networks. In these networks, we distinguish two types of blocking, the new-call blocking, which concerns the initial call establishment request, and the handoff-call blocking, due to the users’ mobility from one cell to the other. To analyze the(More)
Virtual Path Bandwidth (VPB) control and Virtual Circuit Routing (VCR) control are competitive control schemes for traffic management in ATM networks. The objective of both controls is to minimize the Call Blocking Probability (CBP) of the congested end-to-end links, under constraints posed by the transmission links capacity of the network. Firstly, we(More)
We propose a new teletraffic model, named Wireless Engset Multi-rate Loss Model (W-EnMLM) for the call-level analysis of W-CDMA networks, supporting heterogeneous service-classes of finite population of traffic sources. Quasirandom arriving calls (generated by mobile users), compete for their admission to a W-CDMA cell under the Complete bandwidth Sharing(More)