MEASUREMENT AND LOCATION PREDICTION IN AN INDOOR WLAN USING OPTIMIZATION AND SIMULATION

Abstract

In the new era of wireless communication, Wireless Local Area Network (WLAN) has emerged as one of the key players in the wireless communication family. The prohibitive cost of building wired network infrastructures has paved the way for wireless networking on a global scale. WLANs are being used as an alternative to the high installation and maintenance costs incurred by traditional additions, deletions and changes experienced in wired LAN infrastructures. Physical and environmental necessity is another driving factor in favour of WLANs. It is now a trend to develop the WLAN in various colleges and office campuses for increasing productivity and quality of goods. WLAN hold the promise of increasing employee productivity by providing them ubiquitous connectivity and mobility across enterprise. In the WEAN category the products based on, the IEEE 802.11g technology are dominating which offers speeds of up to 54Mbps and covers a range of up to 100 meters. Prediction of the signal strength for indoor propagation environments can be faced with many obstacles and the effects of multipath propagation such as signal attenuation, reflection and diffraction. Depending on the building construction and layout, the signal usually propagates along corridors and into other open areas. In some cases, transmitted signals may have a direct path (Line-of-Site, LOS) to the receiver. LOS examples of indoor spaces are warehouses, factory floors, auditoriums, and enclosed stadiums. OBJECTIVE OF THE PRESENT WORK The objective of the present work is to analyze the measured data in terms of signal strength in the indoor WLAN 802.11g at Malviya Bhavan, Boys hostel Building, Indian Institute of Technology, Roorkee, Saharanpur Campus coverage using optimization technique and simulation. The outline of the present work is as follows: • Collection of data for received signal strength at frequency of 2.4 GHz using Spectrum Analyzer for different scenarios at Malviya Bhavan, Boys hostel Building, Indian Institute of Technology, Roorkee, Saharanpur Campus. • The assessment of coverage of access points using QUALNET 5.0 simulation design tool in Indoor WLAN using above data. • The assessment of coverage of access points using Particle Swarm Optimization to find the coordinates of APs for their locations based on above measurements. • Analyzed the effect of interference due to obstacles such as walls, tables, chairs and other elements in the indoor environment. • The optimized results have been compared with the observed results. Methodology The measurements have been conducted in the Malviya Bhawan, Boys Hostel Building, IIT Roorkee, Saharanpur Campus to collect data for simulation & optimization. Using Spectrum Analyzer, the received signal strength of the access points has been calculated using omnidirectional antenna. The experiment has been conducted in building considering free space and line of sight in the design area which has dimensions of 64m x 60m and have 400 users on four floors. The facility is a four floor (Ground floor to third floor) building and nineteen access points are distributed around the building in different block points installed by the network administrator in the corridors of the building. None at the ground level, ten on the first floor, nine on the second floor and none on the third floor. Set up for experimental data: Domain Area: Malviya Bhawan, Boys Hostel, [IT Roorkee, Saharanpur Campus Area: 64m X 60m Type: Four floor Building Device: MSA338 3.3 GHz Spectrum Analyser, Omnidirectional Antenna, Access Point AP (LINK DWL-3200AP) MAS 300 PC software for Spectrum Analyzer Optimization Technique: Particle Swarm Optimization PROPAGATION COVERAGE IN INDOOR WLAN USING SIMULATION SOFTWARE Researchers generally use simulation to analyze system performance prior to physical design or to compare multiple alternatives over a wide range of conditions in the wireless local area network. In the past few years much of the work has been done using simulation software to improve the performance of Wireless local area network. vi Contribution: The QUALNET 5.0 simulation design tool is used for the performance coverage of the WLAN access points installed at Malviya Bhawan, Boys Hostel Building, IIT Roorkee, Saharanpur Campus. In the simulation, Random Waypoint Model and Hellman Ford Algorithin have been used for free space in case of line of sight. Two Ray model has been used in case of the interferences and obstructions present in the building. The optimum coverage of the users has been estimated using simulation software for the coverage area of the site. PLACEMENT OF ACCESS POINTS OF INDOOR WLAN USING PARTICLE SWARM OPTIMIZATION TECHNIQUE The mathematical model of the placement of AP can be formulated as a non-linear optimization problem, for which a suitable technique is needed for obtaining the solution. Determining an optimal location for the placement of AP is a crucial task while dealing with WLAN. Owing to its non linear nature, a suitable technique is needed for its solution. In the past few years much focus has been laid on nontraditional nature inspired optimization algorithms. Some of the popular methods include Genetic Algorithms (GA), Differential Evolution (DE) and Particle Swarm Optimization (P50). Contribution: ?SO is used for determining the optimal location of AP installed at Malviya Bhawan. The objective function is based on minimizing the average path loss received over the entire design area and maximum path loss received by any receiver. Numerical results obtained by PSO are compared with the actual placement of AP. It is observed that PSO can be an attractive alternative for dealing with such type of problems. COVERAGE AND ANALYSIS OF OBSTRUCTED ENVIRONMENT IN INDOOR WLAN In real life scenario, the performance of WLAN is often affected by obstructions like wood (furniture, doors, windows etc), brick (walls), steel (ahnirahs) and many other such things. Consequently, the placement of AP is to be done accordingly. The formulation of the objective function, nonlinear in nature, changes according to the type of obstruction being considered. vii Contribution: Simulation software and Optimization technique is used for analysing the path losses obtained by the effects of multipath propagation such as reflection, diffraction and scattering and the interferences caused by the obstacles such as soft partitions like tables, chairs, desk, human being and by the hard partitions like wooden door, brick wall, almirah and other elements in the indoor environment as there are many variables in building construction that affect 2.40-lz transmission because the building used has its own characteristics depending on the materials and the physical structure. Finally the optimized results have been compared with the observed results.