1. Submission doc.: IEEE 802.19-15/0065r0 July 2015 Alaa Mourad, BMW GroupSlide 1 Coexistence Management in the 2.4GHz ISM Band in the automotive enviroment Date: 2015-07-22 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.

2. Submission doc.: IEEE 802.19-15/0065r0 July 2015 Alaa Mourad, BMW GroupSlide 2 Abstract This document highlights the coexistence problem in the ISM 2.4GHz band in the automotive domain. Measurement results, which were done to optimize the position of WLAN/BT Antenna in car, are presented

3. Submission doc.: IEEE 802.19-15/0065r0 July 2015 Alaa Mourad, BMW GroupSlide 3 Introduction In the past years, more and more wireless systems (WLAN, Bluetooth and Kleer) have migrated into the automotive environment, in order to support different applications like (Hands free, Streaming application and internet browsing). It is expected that the percentage of cars with built-in connectivity will reach 90% by 2020. The coexistence management in the automotive environment is quite challenging due to the increased number of CE devices inside the vehicle and the small distances. The interference from neighbouring vehicles and surrounding infrastructure will make the problem more complicated.

4. Submission doc.: IEEE 802.19-15/0065r0 July 2015 Alaa Mourad, BMW GroupSlide 4 Previous Activities In 2003, recommended practice [1] addressing the issue of coexistence of wireless local area networks and wireless personal area networks was approved and published by IEEE 802.15.2 task group. The task group has focused mainly on the coexistence between IEEE Std. 802.15.1-2002 and IEEE Std. 802.11b-1999. The coexistence mechanisms were classified as collaborative and non-collaborative depending on the connection between the two systems. Five MAC layer mechanisms and three physical layer mechanisms were presented [1].

5. Submission doc.: IEEE 802.19-15/0065r0 July 2015 Alaa Mourad, BMW GroupSlide 5 Problem Description The solutions which were provided by 802.15.2 focused on 802.11b which is CDMA based, however the new WLAN systems are based on the OFDM (and OFDMA); those mechanisms will not help in the near future due to the increased number of CE devices and the small volume in the car. WLAN at 5GHz band could solve the problem partly, however the available channels at 5GHz band is very limited in some countries (like Japan). This problem should be studied seriously to avoid chaos in the automotive environment.

6. Submission doc.: IEEE 802.19-15/0065r0 July 2015 Alaa Mourad, BMW GroupSlide 6 Measurement Setup Many measurements [2] were performed to optimize the position of WLAN/Bluetooth antenna in car in order to provide good quality of signal inside the car and reduce the interference to the surrounding. Different antenna positionsMeasurement setup

7. Submission doc.: IEEE 802.19-15/0065r0 July 2015 Alaa Mourad, BMW GroupSlide 7 Measurement Results Agilent signal generator (N5183) and Agilent spectrum analyzer (N9010A) were used for the measurements The received power is measured in increments of 5 MHz, the small scale fading effects were eliminated by averaging with 10 KHz bandwidth The path loss was calculated based on the received power taking into account antennas gain and different cable losses It can be seen that the path loss is between 76-86dB at 50[m] depending on the antenna position inside the car. Mean path loss over distance at 2.45GHz

8. Submission doc.: IEEE 802.19-15/0065r0 July 2015 Alaa Mourad, BMW GroupSlide 8 Conclusions Wireless technologies play an increasing role in the automotive domain, WLAN and Bluetooth will be used more and more in the future in order to provide seamless users experience in vehicles. As shown in the presented measurement, the interference between the neighboring cars is not negligible, the path loss is quite high compared to inside the buildings, which makes the automotive environment more challenging than the indoor scenarios. IEEE802.11ax focuses mainly on user experience (QoS) especially in dense deployment scenario, the automotive applications should be considered in order to avoid chaos in the near future.

9. Submission doc.: IEEE 802.19-15/0065r0 July 2015 Alaa Mourad, BMW GroupSlide 9 References [1] IEEE 802.15.2, Part 15.2: Coexistence of Wireless Personal Area Networks with Other Wireless Devices operating in Unlicensed Frequency Bands [2] Angle-dependent path loss measurements impacted by car body attenuation in 2.45 GHz ISM band

10. Submission doc.: IEEE 802.19-15/0065r0 Backup Slide 10Alaa Mourad, BMW Group July 2015

11. Submission doc.: IEEE 802.19-15/0065r0 Backup Slide 11Alaa Mourad, BMW Group July 2015 Frequency variation for scenario 3