doc.: IEEE /1140r0 Submission 11n 40 MHz and BT coexistence test results Authors:

doc.: IEEE /1140r0 SubmissionHarish Ramamurthy, Marvell Semiconductor Inc.Slide 2 Objective Measure performance impact on n and Bluetooth (BT) when n operates in 20 MHz and 40 MHz Measurements made in accordance to test scenarios specified in [1] and [2] Test Scenarios –BT Profiles: SCO, ACL and A2DP –802.11n: 20 MHz/40 MHz

doc.: IEEE /1140r0 SubmissionHarish Ramamurthy, Marvell Semiconductor Inc.Slide 3 Test Setup Anechoic shielded room used Separation of WLAN devices is 3m due to test facility constraints 11g performance not measured due to time constraints Laptop is the primary n transmitter n Setup –Throughput test using IxChariot –Aggregation ON and video priority used to maximize medium utilization

doc.: IEEE /1140r0 SubmissionHarish Ramamurthy, Marvell Semiconductor Inc.Slide 4 BT Adaptive Frequency Hopping (AFH) Definitions AFH off –All 79 MHz channels are used and none of the channels are blocked AFH on: Two types of AFH used –Manual AFH –Manually remove or blacklist channels that get affected by and some margin at the edges. –For e.g. when using 40 MHz with 2, 6 channel, block all lower channels (except for first four) and enable all higher channels (top twenty seven) –Regular AFH Present results with both regular and manual AFH

doc.: IEEE /1140r0 SubmissionHarish Ramamurthy, Marvell Semiconductor Inc.Slide 5 Tests Outline Quantitative Test Setups –#1: SCO: Measure Mean Opinion Score (MOS) –#2: ACL: Measure BT throughput Qualitative Test Setups –#4: SCO –#5.1: A2DP: Distance between BT and n = 0.5 meters –#5.2: A2DP: Distance between BT and n = 0.5 meters –#5.3: A2DP: Distance between BT and n = 1.5 meters

doc.: IEEE /1140r0 SubmissionHarish Ramamurthy, Marvell Semiconductor Inc.Slide 6 Test Setup #1: BT SCO performance Refers to use-case 1 of [1] & [2]. Adjustments –22 Mbps data rate not measured due to time constraints Setup –Refer slide 3. –Bluetooth Setup SCO link: MOS measured using PESQ P.862 method AFH on: Manual AFH was used –The tester was standing between bluetooth devices

doc.: IEEE /1140r0 SubmissionHarish Ramamurthy, Marvell Semiconductor Inc.Slide 7 Test Setup #1: BT SCO performance No n throughput throttling Baseline (AFH off) n 20MHz (AFH off) n 40MHz (AFH off) Baseline (AFH on) n 20MHz (AFH on) n 40MHz (AFH on) BT MOS Average n Mbps Throughput 20 MHz: MHz: MHz: MHz: n throughput: 1 Mbps Baseline (AFH off) n 20MHz (AFH off) n 40MHz (AFH off) Baseline (AFH on) n 20MHz (AFH on) n 40MHz (AFH on) BT MOS Average n Mbps Throughput

doc.: IEEE /1140r0 SubmissionHarish Ramamurthy, Marvell Semiconductor Inc.Slide 8 Setup –Refer slide 3. –Bluetooth Setup ACL link: packets of length 160 bytes of type DH5 Maximum achievable throughput in this configuration is about 315 kbps BT performance: Measure throughput AFH on: Manual AFH was used Test Setup #2: ACL performance

doc.: IEEE /1140r0 SubmissionHarish Ramamurthy, Marvell Semiconductor Inc.Slide 9 Test Setup #2: ACL performance No n throughput throttling Baseline (AFH Off) n 20MHz (AFH off) n 40MHz (AFH off) Baseline (AFH on) n 20MHz (AFH on) n 40MHz (AFH on) BT Average (kbps) Average (Mbps) 20 MHz: MHz: MHz: MHz: n throughput 1 Mbps Baseline (AFH Off) n 20MHz (AFH off) n 40MHz (AFH off) Baseline (AFH on) n 20MHz (AFH on) n 40MHz (AFH on) BT Average (kbps) Average (Mbps) 1/111 11

doc.: IEEE /1140r0 SubmissionHarish Ramamurthy, Marvell Semiconductor Inc.Slide 10 Discussion: Quantitative Test Results n High medium utilization (No throughput throttling) –Without AFH, performance of BT degrades in the presence of n for both 20 and 40MHz MOS is not acceptable for both 20 MHz and 40 MHz n throughput also gets severely affected (down 30 %) –Manual AFH greatly improves the performance of BT in the presence of n for both 20 and 40MHz MOS is comparable for 20 MHz and 40 MHz n throughput has slight degradation n Low medium utilization (1 Mbps) –802.11n and BT performance are not degraded considerably (<10%)

doc.: IEEE /1140r0 SubmissionHarish Ramamurthy, Marvell Semiconductor Inc.Slide 11 Qualitative Tests Perception tests for audio quality of BT SCO and A2DP in presence of n 20 MHz and 40 MHz The data presented here is for reference only and it is not intended to be interpreted as comparing different implementations and their performance. Results are presented for limited number of scenarios Note –“blips”: minor interruption in audio of duration <2 second –“dropouts”: major interruption in audio of duration >= 2seconds

doc.: IEEE /1140r0 SubmissionHarish Ramamurthy, Marvell Semiconductor Inc.Slide 12 Test Setup #4: BT SCO – Qualitative Tests Equipment –Plantronics Voyager 855 headset and Marvell BT Setup similar to use-case 1 of [1] & [2]. Adjustments 22 Mbps data rate not measured due to time constraints AFH –Regular AFH

doc.: IEEE /1140r0 SubmissionHarish Ramamurthy, Marvell Semiconductor Inc.Slide 13 Test Setup #4: BT SCO – Qualitative Test Results AFH Disabled –802.11n: No throughput throttling 20 MHz: Audio is distorted but remains intelligible (on the threshold of being acceptable/unacceptable) 40 MHz: Audio is heavily distorted and marginally intelligible (unacceptable) –Running 1 Mbps (Both 20 MHz and 40 MHz) Audio quality is very good but do hear occasional dropouts (not often) AFH Enabled –Regular AFH –802.11n: No throughput throttling Audio quality was very good for both 20 MHz and 40 MHz With 40 MHz hear slightly higher number of dropouts –802.11n: 1 Mbps throughput. For both 20 MHz and 40 MHz: No audible effect

doc.: IEEE /1140r0 SubmissionHarish Ramamurthy, Marvell Semiconductor Inc.Slide 14 Test Setup #5.1: BT A2DP Equipment –Marvell BT Devices Setup similar to use-case 3 of [1] & [2]. Refer slide 4. AFH –Manual AFH

doc.: IEEE /1140r0 SubmissionHarish Ramamurthy, Marvell Semiconductor Inc.Slide 15 Test Setup #5.1: BT A2DP – No n throughput throttling – Qualitative Test Results AFH Mode Throughput (Mbps)BT Performance OFFBaseline20 MHz: 98.6 (802.11n only) 40 MHz: (802.11n only) Good audio quality, Rare blips (BT Only) OFF20 MHz87.3Lower number of blips- ~10% - Audio quality is good OFF40 MHz119Several blips and some dropouts - ~25% - Audio quality is not good ONBaseline20 MHz: 98.6 (802.11n only) 40 MHz: (802.11n only) Good audio quality, Rare blips (BT Only) ON20 MHz96.5Good audio quality, Rare blips ON40 MHz176.7Good audio quality, Very few blips

doc.: IEEE /1140r0 SubmissionHarish Ramamurthy, Marvell Semiconductor Inc.Slide 16 Test Setup #5.1: BT A2DP – Varying Throughput – Qualitative Test Results AFH Mode Throughput (Mbps)BT Performance OFFBaseline20 MHz: 98.6 (802.11n only) 40 MHz: (802.11n only) Good audio quality, Rare blips (BT only) OFF20 MHz< 60 Mbps*Good audio quality, Very few blips OFF40 MHz< 90 Mbps*Good audio quality, Very few blips * Empirical search: Throughput was varied in steps of 5 Mbps

doc.: IEEE /1140r0 SubmissionHarish Ramamurthy, Marvell Semiconductor Inc.Slide 17 Test Setup #5.2: BT A2DP – Qualitative Tests Equipment –Plantronics Pulsar 590A headset and stereo adapter Setup similar to use-case 3 of [1] & [2]. Adjustments: 22 Mbps data rate not measured due to time constraints AFH –Regular AFH

doc.: IEEE /1140r0 SubmissionHarish Ramamurthy, Marvell Semiconductor Inc.Slide 18 Test Setup #5.2 : BT A2DP – Qualitative Test Results AFH Disabled –802.11n: No throughput throttling. For both 20 MHz and 40 MHz Lots of dropouts. Audio quality was not acceptable –1 Mbps (Both 20 MHz and 40 MHz) Audio quality is very good but hear dropouts occasionally AFH Enabled –802.11n: No throughput throttling 20 MHz: Periods of music and periods of dropouts. 40 MHz: Lots of dropouts. Audio quality was not acceptable –Regular AFH algorithm i.e. no manual blacklisting

doc.: IEEE /1140r0 SubmissionHarish Ramamurthy, Marvell Semiconductor Inc.Slide 19 Test Setup #5.3: BT A2DP Equipment –Plantronics Pulsar 590A headset and stereo adapter Setup similar to use-case 3 of [1] & [2]. Adjustments: Increased distance between tx and BT tx to 1.5m 22 Mbps data rate not measured due to time constraints AFH –Regular AFH algorithm i.e. no manual blacklisting

doc.: IEEE /1140r0 SubmissionHarish Ramamurthy, Marvell Semiconductor Inc.Slide 20 Test Setup #5.3: BT A2DP – Qualitative Test Results AFH Disabled –802.11n: No throughput throttling 20 MHz: Audio quality is good but do hear blips 40 MHz: Audio quality is good but because of higher dropouts it is not acceptable AFH Enabled –802.11n: No throughput throttling 20 MHz: Audio quality is very good 40 MHz: Audio quality is good to very good with some blips

doc.: IEEE /1140r0 SubmissionHarish Ramamurthy, Marvell Semiconductor Inc.Slide 21 Discussion: Qualitative Test Results SCO –No tests were done with manual AFH –With regular AFH enabled, the audio went from unacceptable to near perfect A2DP –With regular AFH With distance between BT Tx and Tx equal to 0.5 m, audio quality for both 20 MHz and 40 MHz was unacceptable With distance increased to 1.5 m, audio quality improved significantly for both 20 MHz and 40 MHz Note: The headset remained 0.5 m away from n Tx. This still emulates a user working on a laptop while listening to music and amounts to moving the BT tx (stereo) away by 1m –With manual AFH Audio quality is good in both 20 MHz and 40 MHz

doc.: IEEE /1140r0 SubmissionHarish Ramamurthy, Marvell Semiconductor Inc.Slide 22 References [1] “11n 40MHz BT test cases”, Eldad Perahia (Intel) et al –Available at 000n-11n-40mhz-bt-test-cases.ppthttps://mentor.ieee.org/802.11/file/08/ n-11n-40mhz-bt-test-cases.ppt [2] “Bluetooth test cases for n 40 MHz”, John R. Barr (Motorola) et al –Available at 000n-bluetooth-test-cases-for n-40-mhz.ppthttps://mentor.ieee.org/802.11/file/08/ n-bluetooth-test-cases-for n-40-mhz.ppt

doc.: IEEE /1140r0 Submission Backup Slides Setup, detailed test results etc.

doc.: IEEE /1140r0 SubmissionHarish Ramamurthy, Marvell Semiconductor Inc.Slide 24 Test Setup #1: SCO performance Baseline (AFH off) 11n 20MHz (AFH off) 11n 40MHz (AFH off) Baseline (AFH on) 11n 20MHz (AFH on) 11n 40MHz (AFH on) BT MOS Average n Mbps Throughput 98.4/ /

doc.: IEEE /1140r0 SubmissionHarish Ramamurthy, Marvell Semiconductor Inc.Slide 25 Test Setup #1: SCO performance with 1Mbps 11n Throughput Baseline (AFH off) 11n 20MHz (AFH off) 11n 40MHz (AFH off) Baseline (AFH on) 11n 20MHz (AFH on) 11n 40MHz (AFH on) BT MOS Average n Mbps Throughput 1/111 11

doc.: IEEE /1140r0 SubmissionHarish Ramamurthy, Marvell Semiconductor Inc.Slide 26 Test Setup #2: ACL performance Baseline (AFH Off) n 20MHz (AFH off) n 40MHz (AFH off) Baseline (AFH on) n 20MHz (AFH on) n 40MHz (AFH on) BT Average (Kbps) Average (Mbps) 97.06/ /

doc.: IEEE /1140r0 SubmissionHarish Ramamurthy, Marvell Semiconductor Inc.Slide 27 Test Setup #2: ACL performance – n 1 Mbps throughput Baseline (AFH Off) n 20MHz (AFH off) n 40MHz (AFH off) Baseline (AFH on) n 20MHz (AFH on) n 40MHz (AFH on) BT Average (Kbps) Average (Mbps) 1/111 11