1. doc.: IEEE 19-08-0027-02-0000-40MHz-11n-impact-on-bluetooth Submission July 2008 Texas InstrumentsSlide 1 IEEE 802.11n 40 MHz Impact on BT Performance Date: 2008-07-16 Authors: Notice: This document has been prepared to assist IEEE 802.19. 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 802.19. 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 TAG 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 802.19 TAG. If you have questions, contact the IEEE Patent Committee Administrator at.http:// ieee802.org/guides/bylaws/sb-bylaws.pdfpatcom@ieee.org

2. doc.: IEEE 19-08-0027-02-0000-40MHz-11n-impact-on-bluetooth Submission July 2008 Texas InstrumentsSlide 2 Outline Motivation Simulation Scenario and Assumptions WLAN Interference Calculations Results Conclusions

3. doc.: IEEE 19-08-0027-02-0000-40MHz-11n-impact-on-bluetooth Submission July 2008 Texas InstrumentsSlide 3 Motivation IEEE 802.11n standard proposed an optional 40 MHz transmission Impact of 40 MHz transmissions on non-IEEE 802.11 devices has not been investigated This work addresses impact of 40 MHz transmissions (in 2.4 GHz) on BT devices

4. doc.: IEEE 19-08-0027-02-0000-40MHz-11n-impact-on-bluetooth Submission July 2008 Texas InstrumentsSlide 4 Scenario Under Investigation Networks: –WLAN Network consists of one STA and one AP The STA is closer to BT transmitting device –BT Network consists of BT Master and BT Slave Traffic –64 Kbps voice traffic from BT_Master to BT_Slave carried using SCO or eSCO packets –60 Mbps FTP traffic from STA to AP for 40 MHz option and 30 Mbps FTP traffic from STA to AP for 20 MHz option PHY –Tx Power: 15 dBm –WLAN 20 MHz PHY rate: 104 Mbps –WLAN 40 MHz PHY rate: 162 Mbps –Aggregation: 6KB maximum –BT PHY: 4 dBm Tx Power and PHY rate of 1 Mbps for SCO and 2 Mbps for eSCO Location –AP: 40 meters away from STA –STA: 1 meter away from BT Master and BT Slave –BT Master and BT Slave distance: 1 meter

5. doc.: IEEE 19-08-0027-02-0000-40MHz-11n-impact-on-bluetooth Submission July 2008 Texas InstrumentsSlide 5 WLAN Interference on BT WLAN interference power in BT receiver Substituting interference for noise, SNR for the interfered bits at BT is given as: Received BT power and WLAN interference at BT receiver is calculated using free space path loss model

6. doc.: IEEE 19-08-0027-02-0000-40MHz-11n-impact-on-bluetooth Submission July 2008 Texas InstrumentsSlide 6 PER Calculations Given that BT and WLAN overlap in frequency, and an overlapping interval,  t, and knowing tx_rate for BT packet, the number of BT bits (interfered) is calculated as: For a given run, the BER for the interfered bits is obtained based on the SNR given earlier. Assuming zero errors for the interference-free bits, the PER is approximated as: The overall PER is obtained from averaging the PER’s found in different runs

7. doc.: IEEE 19-08-0027-02-0000-40MHz-11n-impact-on-bluetooth Submission July 2008 Texas InstrumentsSlide 7 BER Curves BER for GFSK and pi/4-DQPSK in presence of AWGN (Ref[1] &[2])

8. doc.: IEEE 19-08-0027-02-0000-40MHz-11n-impact-on-bluetooth Submission July 2008 Texas InstrumentsSlide 8 BT PER Increase Using 20 MHz as Baseline

9. doc.: IEEE 19-08-0027-02-0000-40MHz-11n-impact-on-bluetooth Submission July 2008 Texas InstrumentsSlide 9 BT Throughput Reduction Using 20 MHz as Baseline

10. doc.: IEEE 19-08-0027-02-0000-40MHz-11n-impact-on-bluetooth Submission July 2008 Texas InstrumentsSlide 10 BT PER Increase with Aggregation Using 20 MHz as Baseline

11. doc.: IEEE 19-08-0027-02-0000-40MHz-11n-impact-on-bluetooth Submission July 2008 Texas InstrumentsSlide 11 BT Throughput Reduction with Aggregation Using 20 MHz as Baseline

12. doc.: IEEE 19-08-0027-02-0000-40MHz-11n-impact-on-bluetooth Submission July 2008 Texas InstrumentsSlide 12 Conclusions 40 MHz operation drastically degrades HV3 performance If voice performance is already at a threshold, 10% increase in PER is disastrous 40 MHz operation in 2.4GHz is harmful to non-WLAN networks IEEE 802.11n should consider removing 40 MHz in 2.4 GHz

13. doc.: IEEE 19-08-0027-02-0000-40MHz-11n-impact-on-bluetooth Submission July 2008 Texas InstrumentsSlide 13 References [1] D. Patrick and R. Morrow, “Wireless Network Coexistence”, McGraw-Hill Professional 2004. [2] Agilent Technologies, “Bluetooth Design Guide”, August 2005. [3] 19-08-0018-01-0000-40mhz-11n-bluetooth-sim- parameters.doc