doc.: IEEE /1158r0 Submission November 2005 Uriel Lemberger, IntelSlide 1 Rx Sensitivity Metrics in Conductive Test Environment Notice: This document has been prepared to assist IEEE It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE Patent Policy and Procedures: The contributor is familiar with the IEEE 802 Patent Policy and Procedures, including the statement "IEEE standards may include the known use of patent(s), including patent applications, provided the IEEE receives assurance from the patent holder or applicant with respect to patents essential for compliance with both mandatory and optional portions of the standard." Early disclosure to the Working Group of patent information that might be relevant to the standard is essential to reduce the possibility for delays in the development process and increase the likelihood that the draft publication will be approved for publication. Please notify the Chair as early as possible, in written or electronic form, if patented technology (or technology under patent application) might be incorporated into a draft standard being developed within the IEEE Working Group. If you have questions, contact the IEEE Patent Committee Administrator at. Date: November 2005 Authors:

doc.: IEEE /1158r0 Submission November 2005 Uriel Lemberger, IntelSlide 2 Abstract This document introduces the description of the measurement of the Receive Sensitivity metric in a Conductive Test Environment for performance testing of wireless LAN devices. This presentations corresponds to the document t-RX-Sensitivity-Metric-in-Conductive-Setup.doc and it extends the metrics covered by document t.

doc.: IEEE /1158r0 Submission November 2005 Uriel Lemberger, IntelSlide 3 Summary Purpose Test Equipment Typical setup Test description.

doc.: IEEE /1158r0 Submission November 2005 Uriel Lemberger, IntelSlide 4 Purpose of Rx sensitivity test This is a secondary metric that is defined in which helps understanding the DUT Receiver PER vs. Attenuation performance.

doc.: IEEE /1158r0 Submission November 2005 Uriel Lemberger, IntelSlide 5 Test Equipment DUT – any wireless device (AP or Client) that includes relevant SW running on the specific platform WLCP (WireLess CounterPart) - reference AP or a reference Client Shielded enclosure for DUTs and WLCPs in order to isolate from extraneous signals Cables –RF-cables – connected to antenna connectors. –Wired LAN cables –Control cables Attenuators – to control attenuation (which means path loss) and RF signal input power

doc.: IEEE /1158r0 Submission November 2005 Uriel Lemberger, IntelSlide 6 Test Equipment (cont.) Calibrated combiners, splitters and couplers – to handle different RF path, including antennas entries. Power Meter Devices – to measure RF signal power per packet Wired Traffic Generator to generate data traffic from DUT to WLCP and from WLCP to DUT on top of layer 2. Wired Traffic Analyzer to gather delivered data payload over time through wired interface on top of layer 2.

doc.: IEEE /1158r0 Submission November 2005 Uriel Lemberger, IntelSlide 7 Test Equipment (cont.) Test controller Includes the following capabilities, likely automated and controlled by dedicated SW: –The ability to control TX rates and TX power of WLCP and DUT –The ability to control power meters. –The ability to control attenuators –The ability to control Wired Traffic Analyzer –The ability to control Wired Traffic Generator.

doc.: IEEE /1158r0 Submission November 2005 Uriel Lemberger, IntelSlide 8 Rx sensitivity conductive setup

doc.: IEEE /1158r0 Submission November 2005 Uriel Lemberger, IntelSlide 9 Calibration and isolation of the setup The setup shall be properly isolated from external interference and other unwanted signals. Prior to beginning the specific test, the test equipment shall be calibrated, taking into account losses due to cables, couplers, splitters, etc. All test software shall be verified. The test setup may be monitored during the test to ensure that the test conditions do not change unintentionally.

doc.: IEEE /1158r0 Submission November 2005 Uriel Lemberger, IntelSlide 10 Rx sensitivity Test This secondary metric is the input signal level at the point –where the number of successfully transferred data payload packets vs. the overall sent data packets (from MAC SAP of WLCP to MAC SAP of DUT) –meets the threshold requirement as specified in the specs. The RX Power of the RF signal measured at the antenna connector of DUT is controlled by the Attenuation between the DUT and WLCP. Applicable for wireless clients, both IBSS and BSS Correlates with end-user experiences of TPT vs. range in a real life environment which is dependent on Rx sensitivity and rate scaling.

doc.: IEEE /1158r0 Submission November 2005 Uriel Lemberger, IntelSlide 11 RX PER calculation #_packets_sent is the number of broadcast data packets that were injected to WLCP through wired interface by Traffic Generator and transmitted by WLCP. –Each broadcast data packet is transmitted once and ACK is not required. –Multicast packet may be used instead of Broadcast packets. #_packets_delivered is the number of broadcast data packets that were injected to WLCP through wired interface by Traffic Generator, transmitted by WLCP and captured by Wired Traffic Analyzer via wired interface. PER = (#_packets_sent - #_packets_delivered ) / (#_packets_sent).

doc.: IEEE /1158r0 Submission November 2005 Uriel Lemberger, IntelSlide 12 Procedure Setup DUT according to the initial configuration and associate with WLCP. Enforce WLCP to transmit broadcast data packets on the specific rate, measure PER vs. Attenuation and record PER per fixed rate. –Repeat for all relevant fixed rates. –Calculate the maximal Received signal level where the PER is above the threshold.

doc.: IEEE /1158r0 Submission November 2005 Uriel Lemberger, IntelSlide 13 Procedure - details Step 0: Setup DUT to the initial configuration and associate with WLCP. Step 1: Set attenuation current_value=min_value. Step 2: –Test controller generates data traffic such that WLCP generates the number of broadcast packets (1000) to DUT with specific rate. –packet size set as specified by spec (1000 or 1024). –The WLCP TX power is measured and recorded. –Test Controller counts the number of packets received by DUT and recorded. –Calculate PER=(#_packets_sent-#_packets_delivered)/#_packets_sent Step 3: Set attenuation current_value+=step_value Step 4: Repeat steps 2-3 until PER>10% (spec threshold 8% or 10%) Step 5: Repeat steps 0-4 for another channel Each attenuation value should be translated to DUT RX Power based on measured TX Power of WLCP, cables lost and attenuation values Optional modifier is Ambient temperature.

doc.: IEEE /1158r0 Submission November 2005 Uriel Lemberger, IntelSlide 14 Reporting The results can be summarized in the following table: Transmit Rate: rate Channel: channel Transmit Power (dBm)Attenuatio n (dB ) RX Power Level (dBm) Number of transmitted packets Number of received packets PER = 1-Recieved/Transmitted The results should be reported as a table or a graph of PER(RxPowerLevel) The Sensitivity should be calculated and reported as the point where the PER reaches percentage as define by the spec (10% OFDM, 8% CCK and DSSS)

doc.: IEEE /1158r0 Submission November 2005 Uriel Lemberger, IntelSlide 15 Example of reporting table for one test Transmit Rate: 54MbpsChannel:11a, 5180MHz WLCP_TX_ Power [dBm] Attenuation [dB] Setup_Path _Loss [dB] RX_Input_Power [dBm] = WLCP_TX_Power – Attenuation - Setup_Path_Loss Number of transmitted packets Received packets RX PER [%]

doc.: IEEE /1158r0 Submission November 2005 Uriel Lemberger, IntelSlide 16 Example of reporting graph with multiple units

doc.: IEEE /1158r0 Submission November 2005 Uriel Lemberger, IntelSlide 17 Example Rx sensitivity summary report

doc.: IEEE /1158r0 Submission November 2005 Uriel Lemberger, IntelSlide 18 Conclusions The Rx Sensitivity test has been proposed The proposal contains: –Purpose of the metric –Requirements for equipment –Requirements for test conditions –Description of the metric –Description of the setup –Procedure –Baseline, modifiers and test parameters –Reporting results requirements –Examples Recommendation: –Recommend TGT to adopt the content of document 11-05/XXXXr0 into the P draft.

doc.: IEEE /1158r0 Submission November 2005 Uriel Lemberger, IntelSlide 19 References [1] IEEE [2] IEEE /0661r0 TGT Conductive Test Environment and Metrics. Alexander Tolpin.