January 2006 doc IEEE 802 15 15 06

January, 2006 doc. : IEEE 802. 15 -15 -06 -0018 -00 -003 c Project: IEEE P 802. 15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Medium Access Control (MAC) in Wireless PAN using Directional Antennas] Date Submitted: [16 January, 2006] Source: [Chun-Ting Chou, Alireza Seyedi and Richard Chen] Company [Philips] Address [345 Scarborough Rd, Briarcliff Manor, NY 10510] Voice: [914 945 6099], FAX: [914 945 6330], E-Mail: [chun-ting. chou@philips. com] Re: [N/A] Abstract: [Investigation of required MAC functionalities, given the introduction of directional antennas in 802. 15. 3 c physical layer] Purpose: [Discuss required MAC functionalities, given the introduction of directional antennas in 802. 15. 3 c physical layer] Notice: This document has been prepared to assist the IEEE P 802. 15. 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 acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P 802. 15. NOTE: Update all red fields replacing with your information; they are required. This is a manual update in appropriate fields. All Blue fields are informational and are to be deleted. Black stays. After updating delete this box/paragraph. Submission 1 Chun-Ting Chou, Philips

January, 2006 doc. : IEEE 802. 15 -15 -06 -0018 -00 -003 c Medium Access Control (MAC) in Wireless PAN using Directional Antennas Opportunities and challenges Submission 2 Chun-Ting Chou, Philips

January, 2006 doc. : IEEE 802. 15 -15 -06 -0018 -00 -003 c Outline • Background • Benefits of Directional Antennas • Challenges at MAC layer • Issues of existing IEEE 802. 15. 3 MAC • Conclusions Submission 3 Chun-Ting Chou, Philips

January, 2006 doc. : IEEE 802. 15 -15 -06 -0018 -00 -003 c Background • IEEE 802. 15. 3 c Task Group is generating a high rate mm wave (60 GHz) alternate PHY for 802. 15. 3. • High frequency results in high path-loss. Hence, exploiting antenna gain is necessary. • High frequency enables us to design small directional antennas and/or antenna arrays. – What functionalities are necessary and/or beneficial for a WPAN MAC with directional antennas. – Is 802. 15. 3 MAC equipped to handle devices with directional antennas? Submission 4 Chun-Ting Chou, Philips

January, 2006 doc. : IEEE 802. 15 -15 -06 -0018 -00 -003 c Benefits of Directional Antennas Submission 5 Chun-Ting Chou, Philips

January, 2006 doc. : IEEE 802. 15 -15 -06 -0018 -00 -003 c Omni. vs. Directional Antennas • Abstract model • Advantages of directional antennas – Higher gains, longer transmission range – Directional transmission/reception: spatial reuse Tx Rx Submission 6 Chun-Ting Chou, Philips

January, 2006 doc. : IEEE 802. 15 -15 -06 -0018 -00 -003 c Challenges at MAC Layer Submission 7 Chun-Ting Chou, Philips

January, 2006 doc. : IEEE 802. 15 -15 -06 -0018 -00 -003 c Challenge #1: Neighbor Discovery • Different Tx/Rx antenna modes could be used at PHY layer • Three types of neighbors – Omni-omni neighbors – Directional-directional neighbors Submission 8 Chun-Ting Chou, Philips

January, 2006 doc. : IEEE 802. 15 -15 -06 -0018 -00 -003 c Challenge #1: Neighbors Discovery (conti. ) • Mechanisms for neighbor discovery – Discovery of omni-omni neighbors is trivial – New mechanisms are required for discovery of directional-omni and directional-directional neighbors • Location/direction information makes it a lot easier; otherwise, • Intelligent algorithms are needed Submission 9 Chun-Ting Chou, Philips

January, 2006 doc. : IEEE 802. 15 -15 -06 -0018 -00 -003 c Challenge #2: New Hidden-node Problems • The Cause: Deafness – Asymmetry in Tx/Rx antenna gains B B B does not know the transmission between A and Rx A RTS CTS Rx RTS Rx DATA – Directional Transmission/Reception A Rx 1 Submission Rx 2 B A does not know the transmission of B and vice versa 10 Many other Cases !! Chun-Ting Chou, Philips

January, 2006 doc. : IEEE 802. 15 -15 -06 -0018 -00 -003 c Challenge #3: Spatial Reuse • A by-product of directional transmission and reception B A Rx 2 • Advantages: higher spectrum efficiency and user/system throughput (as high as 800% depending on the node density, antenna gain and types [1]-[3], very useful for compensating higher overheard due to high transmission rate) Submission 11 Chun-Ting Chou, Philips

January, 2006 doc. : IEEE 802. 15 -15 -06 -0018 -00 -003 c Challenge #3: Spatial Reuse (conti. ) • A non-trivial problem – Hidden node problems (challenge #2) – Longer interference range B RX 2 A B RX 1 Rx 2 A Rx 1 (b) Interfering concurrent transmissions (a) Interference-free concurrent transmissions • Potential Solutions – Use directional network allocation vector (D -NAV) in distributed networks Submission 12 Chun-Ting Chou, Philips

January, 2006 doc. : IEEE 802. 15 -15 -06 -0018 -00 -003 c Challenge #3: Spatial Reuse (conti. ) – Use space-time scheduling in centralized networks – Antenna gain/power control • without control B Rx 2 Rx 1 A Receive interference from B directional-directional neighbors • with control B Rx 2 Concurrent directional transmission Rx 1 A No interference Submission 13 Chun-Ting Chou, Philips

January, 2006 doc. : IEEE 802. 15 -15 -06 -0018 -00 -003 c Issues of existing IEEE 802. 15. 3 MAC Submission 14 Chun-Ting Chou, Philips

January, 2006 doc. : IEEE 802. 15 -15 -06 -0018 -00 -003 c Existing IEEE 15. 3 MAC • Omni-omni neighbor is assumed • Contention- and polling-based channel mechanism are both used Superframe # m-1 Beacon #m Superframe # m+1 Contention Channel time allocation period access MCTA 1 MCTA 2 CTA 1 CTA 2 CTA n period Piconet controller/devices association via broadcasting beacons (neighbor discovery) Challenge # 1 Submission Superframe # m … CSMA/CA medium access Control for control messages) Scheduled transmission in channel time allocated by piconet controller Challenges # 2 and 3 Challenge # 2 15 Chun-Ting Chou, Philips

January, 2006 doc. : IEEE 802. 15 -15 -06 -0018 -00 -003 c Conclusions • Directional antennas bring in new opportunities – Longer transmission range, higher spectrum efficiency • Challenges at MAC layer – Neighbor discovery, new hidden node problems, spatial reuse and power control • The next step? Submission 16 Chun-Ting Chou, Philips

January, 2006 doc. : IEEE 802. 15 -15 -06 -0018 -00 -003 c References [1] R. Ramanathan and etc. , “Ad Hoc Networking With Directional Antennas: A Complete System Solution, ” IEEE Journal on Selected Areas in Communications, vol. 23, No. 3, Mar. 2005. [2] R. Ramanathan, “On the Performance of Ad Hoc Networks with Beamforming Antennas”, ACM Mobi. Hoc, 2001. [3] R. Choudhury and etc. , “Using Directional Antennas for Medium Access Control in Ad Hoc Networks, ” ACM MOBICOM, 2002. [4] L. Bao and etc. , “Transmission Scheduling in Ad Hoc Networks with Directional Antennas, ” ACM MOBICOM, 2002. [5] T. Korakis and etc. , “A MAC Protocol for Full Exploitation of Directional Antennas in Ad Hoc Wireless Networks, ” ACM Mobi. Hoc, 2003 Submission 17 Chun-Ting Chou, Philips