Wireless propagation channel modeling for optimized Handoff algorithms in wireless LANs q Monji Zaidi a,⇑ , Ridha Ouni b , Rached Tourki a a Electronic and Micro-Electronic Laboratory (ElE, IT-06) FSM, University of Monastir, Monastir 5000, Tunisia b College of Computer and Information Sciences, King Saud University, Saudi Arabia article info Article history: Received 9 November 2009 Received in revised form 5 September 2011 Accepted 12 September 2011 Available online 24 October 2011 abstract In this paper, we present a time-series analysis technique which covers the basic concepts and mechanisms driving the wireless propagation channel. We also use a generated series for simulation study of Handoff performance showing the impact of multipath phenomena. Moreover, the extraction of the average signal has been used to reduce significantly the number of unnecessary Handoffs. The wireless propagation channel modeling is based on the linear model concept of the received power from the access point (AP). This concept has a crucial role in modeling new decentralized Handoff based on the ratio of expected and current signal slopes already pro- vided by the linear model. Hence, a fuzzy-based solution is developed and a comparison with the analytical solution results is established. Until recently, Handoff mechanisms are implemented entirely in software, which increasingly becoming infeasible. Therefore, this work attempt to follow the top-down co-design approach providing hardware proto- type which leads to reduce the power consumption and support high processing speed. Ó 2011 Elsevier Ltd. All rights reserved. 1. Introduction The man-made structures [1] such as buildings or small houses in suburban areas, with sizes ranging from a few meters to tens of meters, dramatically influence the wireless propagation channel. In urban areas, the size of structures can be even larger. Likewise, in rural and suburban environments may reach similar dimensions. These features are similar or greater in size than the transmitted wavelength (metric, decimetric, centimetric waves) and may both block and scatter the radio signal causing specular and/or diffuse reflections. These contributions may reach the mobile station (MS) by way of multiple paths, in addition to that of the direct signal. In many cases, these echoes make it possible that a sufficient amount of energy reaches the receiver, so that the communication link is feasible. This happens especially when the direct signal is blocked. Hence, in addition to the expected distance power decay, two main effects are signaled in mobile propagation: shadowing and multipath [2]. Wireless links have intrinsic characteristics that affect the performance of Handoff protocols. In this paper, we review many simulation models for cellular and WLAN links used in the design of Handoff protocols. We also consider the interplay between wireless links and Handoff. We argue that the design and evaluation of Handoff protocols can be improved by pro- viding available models of wireless links that strike a balance between realism, generality, and detail. We consider how the appropriate models for wireless links can help in Handoff optimization and evaluation. We can identify three levels in the variation rate of the received signal as a function of the distance between the access points (AP) and MS, namely, very slow variations due to the range, slow or long-term variations due to shadowing and fast or 0045-7906/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.compeleceng.2011.09.003 q Reviews processed and approved for publication to Carvalho. ⇑ Corresponding author. Tel.: +216 22691815; fax: +216 73501785. E-mail addresses: Monji.Zaidi@fsm.rnu.tn (M. Zaidi), rouni@ksu.edu.sa (R. Ouni). Computers and Electrical Engineering 37 (2011) 941–957 Contents lists available at SciVerse ScienceDirect Computers and Electrical Engineering journal homepage: www.elsevier.com/locate/compeleceng