Demand-based Network Planning for WLANs

The explosive recent growth in Wireless Local Area Network (WLAN) deployment has generated considerable interest among network designers. Previous design approaches have mostly focused on coverage based optimization or the application of trial and error strategies. These only ensure that adequate signal strength is maintained in the intended service area. WLAN service environments, however, require a network designed to provide not only radio coverage but also adequate capacity (data rate) across the service area so that it can carry traffic load from a large number of users with certain Quality of Service (QoS) requirements. Thus, current design techniques are insufficient to provide data communication services to WLAN users.In this dissertation, a novel approach to the WLAN design problem is proposed that takes into account user population density in the service area, traffic demand characteristics and the structure of the service area. The resulting demand-based WLAN design results in a network that provides adequate radio signal coverage and the required data rate capacity to serve expected user traffic demand in the service region. The demand-based WLAN design model is formulated as a Constraint Satisfaction Problem (CSP). An efficient heuristic solution technique is developed to solve the CSP network design problem in reasonable computational time. The solution provides the number of access points required and the parameters of each access point, including location, frequency channel, and power level. Extensive numerical studies have been reported for various service scenarios ranging from a single floor with small and large service areas to a multiple floor design to a design that includes outside areas. The results of these studies illustrate that the demand-based WLAN design approach is more appropriate for the design of the WLAN systems than are existing coverage based design approaches. Additionally, extensive sensitivity analysis was conducted to study the effects of user activity level (traffic load), shadow fading, and the use of different path loss models in network design

On the Performance Analysis of Coexistence between IEEE 802.11g and IEEE 802.15.4 Networks

This paper presents an intensive measurement studying of the network performance analysis when IEEE 802.11g Wireless Local Area Networks (WLAN) coexisting with IEEE 802.15.4 Wireless Personal Area Network (WPAN). The measurement results show that the coexistence between both networks could increase the Frame Error Rate (FER) of the IEEE 802.15.4 networks up to 60% and it could decrease the throughputs of the IEEE 802.11g networks up to 55%

Robust Floor Determination Algorithm for Indoor Wireless Localization Systems under Reference Node Failure

One of the challenging problems for indoor wireless multifloor positioning systems is the presence of reference node (RN) failures, which cause the values of received signal strength (RSS) to be missed during the online positioning phase of the location fingerprinting technique. This leads to performance degradation in terms of floor accuracy, which in turn affects other localization procedures. This paper presents a robust floor determination algorithm called Robust Mean of Sum-RSS (RMoS), which can accurately determine the floor on which mobile objects are located and can work under either the fault-free scenario or the RN-failure scenarios. The proposed fault tolerance floor algorithm is based on the mean of the summation of the strongest RSSs obtained from the IEEE 802.15.4 Wireless Sensor Networks (WSNs) during the online phase. The performance of the proposed algorithm is compared with those of different floor determination algorithms in literature. The experimental results show that the proposed robust floor determination algorithm outperformed the other floor algorithms and can achieve the highest percentage of floor determination accuracy in all scenarios tested. Specifically, the proposed algorithm can achieve greater than 95% correct floor determination under the scenario in which 40% of RNs failed