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  1. 1. Indoor Propagation Models at 2.4 GHz for 802.11b Networks Dinesh Tummala Department of Engineering Technology
  2. 2. Advisory Committee <ul><li>Dr. Albert B. Grubbs </li></ul><ul><li>Dr. Robert Akl </li></ul><ul><li>Dr. Robert G. Hayes </li></ul><ul><li>Dr. Vijay Vaidyanathan </li></ul>
  3. 3. Outline <ul><li>Introduction </li></ul><ul><li>Problem Statement </li></ul><ul><li>Background of the Problem </li></ul><ul><li>Review of Literature </li></ul><ul><li>Assumptions </li></ul><ul><li>Hypothesis </li></ul><ul><li>Methodology </li></ul>
  4. 4. Introduction <ul><li>Wireless Communication </li></ul><ul><li>The first rush to wireless was for voice. Now, the attention is on data. </li></ul><ul><li>Wireless Local Area Networks (WLANs) provide network services where it is difficult or too expensive to deploy a fixed infrastructure. </li></ul><ul><li>WLANs operate mainly in a indoor environment. </li></ul>
  5. 5. Problem Statement <ul><li>Indoor use of wireless systems poses one of the biggest design challenges. </li></ul><ul><li>It is difficult to predict the propagation of a RF wave in an indoor environment. </li></ul><ul><li>To assist in deploying the above systems, characterization of the indoor radio propagation channel is essential. </li></ul><ul><li>This study aims at developing an indoor propagation model from measurements taken using 802.11b compliant access point and client adapters. </li></ul>
  6. 6. Background of the Problem <ul><li>Line of Sight Propagation </li></ul><ul><ul><li>Attenuation </li></ul></ul><ul><ul><li>Multipath </li></ul></ul><ul><ul><li>Fading </li></ul></ul><ul><ul><li>Free Space Loss </li></ul></ul><ul><ul><li>Noise </li></ul></ul><ul><ul><li>Atmospheric Absorption </li></ul></ul><ul><ul><li>Refraction </li></ul></ul>
  7. 7. Background of the Problem <ul><li>Indoor RF Propagation and Wireless LAN Technology </li></ul><ul><ul><li>Access Points </li></ul></ul><ul><ul><li>Wireless Client Adapter </li></ul></ul>
  8. 8. Background of the Problem <ul><li>IEEE 802.11 Standard </li></ul><ul><ul><li>802.11a </li></ul></ul><ul><ul><li>802.11b </li></ul></ul><ul><ul><li>802.11g </li></ul></ul>
  9. 9. Background of the Problem <ul><li>Frequency Range and Channel Allocation for 802.11b </li></ul>
  10. 10. Background of the Problem <ul><li>802.11b Channel Overlap </li></ul>
  11. 11. Literature Review <ul><li>Existing models tend to focus on a particular characteristic like temporal fading or inter floor losses. </li></ul>
  12. 12. Assumptions <ul><li>The scenarios considered provide a sufficient number of data acquisition values to develop an accurate model. </li></ul><ul><li>The access points considered for signal measurements possess the same antenna behavior in comparison to industry standards. </li></ul>
  13. 13. Hypotheses <ul><li>Null Hypotheses: Indoor radio propagation at 2.4 GHz is not dependent on the indoor environment. </li></ul><ul><li>Alternative Hypotheses: Indoor radio propagation at 2.4 GHz is dependent on the indoor environment. </li></ul>
  14. 14. Methodology <ul><li>Hardware & Software </li></ul><ul><li>Hardware </li></ul><ul><ul><ul><li>Access Points </li></ul></ul></ul><ul><ul><ul><li>Client Adapter </li></ul></ul></ul><ul><ul><li>Software </li></ul></ul><ul><ul><ul><li>NetStumbler </li></ul></ul></ul>
  15. 15. Propagation Environment <ul><li>The power received by a mobile receiver is influenced by the characteristics of the propagation environment. </li></ul><ul><li>The measurements are to be conducted at The College of Engineering, University of North Texas, Research Park. </li></ul>
  16. 16. NTRP 1 st Floor
  17. 17. NTRP 2 nd Floor
  18. 18. CSE Floor Plan
  19. 19. Measurement Scenarios <ul><ul><li>Scenarios used will help in developing signal loss equations, by which a generalization for propagation in an indoor environment at 2.4 GHz can be obtained. </li></ul></ul>
  20. 20. Measurement Scenarios <ul><li>Open corridor </li></ul><ul><li>Closed Corridor </li></ul><ul><li>Class room </li></ul><ul><li>Staircase </li></ul><ul><li>Computer lab </li></ul><ul><li>Two Floor </li></ul>
  21. 21. Data Acquisition <ul><li>Using NetStumbler measurements are taken for the above described scenarios. In each scenario the signal strength is measured for both (LinkSys and D-Link) access points at regular increments of distance. </li></ul><ul><li>At each interval sufficient signal measurements are taken. </li></ul>
  22. 22. Open Corridor Signal level vs Distance
  23. 23. Data Analysis <ul><li>Signal strengths measured in each scenario at different distances are analyzed to get mean signal level values at each distance interval. </li></ul><ul><li>A loss equation is generated for each scenario using the obtained data values. </li></ul><ul><li>A GUI interface is developed to visualize the simulation. </li></ul>
  24. 24. Open Corridor D-Link vs LinkSys
  25. 25. Conclusion <ul><li>Scenarios used will help in developing signal loss equations, by which a generalization for propagation in an indoor environment at 2.4 GHz can be obtained. </li></ul>
  26. 26. Thank You!! <ul><li>Questions? </li></ul>