Proposed framework for WPP

1. Proposed framework for WPP Shravan Surineni, Kevin Karcz InterOperability Lab University of New Hampshire Shravan Surineni, UNH-IOL

2. Purpose • The purpose is to identify the parameters that affect wireless performance and methods to measure these parameters • Well defined metrics and classifying these metrics into categories is necessary before we start to evaluate the parameters • It is likely that these parameters will be handled differently by different people • The purpose of this framework is to discuss the structure and details Shravan Surineni, UNH-IOL

3. Expectations from WPP • WPP will define a set of parameters that are relevant to wireless performance which can be used by designers as well as users • Outline a test method in which these parameters can be measured within a given margin of error • A set of guidelines to get repeatable results with a reasonable error Shravan Surineni, UNH-IOL

4. Performance Categories • Identify and Define parameters at various levels and by user experience • Physical layer - EVM, Spectral mask, CFO, transmit power, sensitivity, immunity to interference, range • MAC layer - Association time, roaming time, throughput, rate adaptation • Network level - Throughput with TCP traffic, UDP traffic • System level - Performance in overlapping BSS Shravan Surineni, UNH-IOL

5. How can we use existing specifications • PICS contain PHY and MAC specifications for conformance with protocol • They provide a direct indication of performance of the particular device • Some of them can be measured directly using commercially available equipment • Detailed methods are required to avoid confusion in making measurements and to get results that are repeatable with reasonable error Shravan Surineni, UNH-IOL

6. Clear methods of testing are needed • Can each layer of the network be measured independently ? • Hassle of real world scenario testing vs. a PHY test mode - PHY test mode or Black box testing ? What models to be used to test performance under multipath? • Which metrics need to look at the interaction of multiple layers • Need test scenario that would give repeatable measurements with a reasonable error Shravan Surineni, UNH-IOL

7. Some grey areas of testing • Throughput • Is throughput measured as a MAC layer payload? At IP layer? TCP or UDP layer? • One DUT may have better PER measurements at the PHY layer than a 2nd DUT, but may get worse throughput if it’s rate selection algorithm is poor. • Difficult to maintain consistency in an open (uncontrolled) environment • Can system throughput be measured in a cabled environment without an antenna? • What if the DUT has a phased array antenna? • What if the device is mini-PCI and inherently has no antenna? • Range test • What if a higher TX level causes higher adjacent channel interference and brings the aggregate throughput down for a neighboring BSS? • Power consumption • Is this just the DC power drain at the cardbus card interface? • Should CPU load be included if the DUT implements much of it’s MAC functionality on a host PC? • Roaming • Quickest time: 1 STA, 2 APs on same channel • More realistic: AP reboots, Multiple STAs roam to new AP on new Channel Shravan Surineni, UNH-IOL

8. Applications may weigh test results differently Shravan Surineni, UNH-IOL

9. Outline of Proposed Method • Define parameters and classify them into various categories • Define test methods to test these parameters • Partial or complete list of items may be tested for different applications • It is likely that these results may be weighted differently by different applications Shravan Surineni, UNH-IOL