Doc.: IEEE 802.15-15-06-0018-00-003c Submission January, 2006 Chun-Ting Chou, PhilipsSlide 1 NOTE:...
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Transcript of Doc.: IEEE 802.15-15-06-0018-00-003c Submission January, 2006 Chun-Ting Chou, PhilipsSlide 1 NOTE:...
January, 2006
Chun-Ting Chou, PhilipsSlide 1
doc.: IEEE 802.15-15-06-0018-00-003c
Submission
NOTE: Update all red fields replacing with your information; they are required. This is a manual update in appropriatefields. All Blue fields are informational and are to be deleted. Black stays. After updating delete this box/paragraph.
Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)Project: IEEE P802.15 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:[[email protected]]
Re: [N/A]
Abstract: [Investigation of required MAC functionalities, given the introduction of directional antennas in 802.15.3c physical layer]
Purpose: [Discuss required MAC functionalities, given the introduction of directional antennas in 802.15.3c physical layer]
Notice: This document has been prepared to assist the IEEE P802.15. 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 P802.15.
January, 2006
Chun-Ting Chou, PhilipsSlide 2
doc.: IEEE 802.15-15-06-0018-00-003c
Submission
Medium Access Control (MAC) in Wireless PAN using Directional
Antennas
Opportunities and challenges
January, 2006
Chun-Ting Chou, PhilipsSlide 3
doc.: IEEE 802.15-15-06-0018-00-003c
Submission
Outline
• Background
• Benefits of Directional Antennas
• Challenges at MAC layer
• Issues of existing IEEE 802.15.3 MAC
• Conclusions
January, 2006
Chun-Ting Chou, PhilipsSlide 4
doc.: IEEE 802.15-15-06-0018-00-003c
Submission
Background
• IEEE 802.15.3c Task Group is generating a high rate
mm wave (60GHz) 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?
January, 2006
Chun-Ting Chou, PhilipsSlide 5
doc.: IEEE 802.15-15-06-0018-00-003c
Submission
Benefits of Directional Antennas
January, 2006
Chun-Ting Chou, PhilipsSlide 6
doc.: IEEE 802.15-15-06-0018-00-003c
Submission
• Abstract model
• Advantages of directional antennas– Higher gains, longer transmission range– Directional transmission/reception: spatial
reuse
Omni. vs. Directional Antennas
TxRx
Tx
Rx
January, 2006
Chun-Ting Chou, PhilipsSlide 7
doc.: IEEE 802.15-15-06-0018-00-003c
Submission
Challenges at MAC Layer
January, 2006
Chun-Ting Chou, PhilipsSlide 8
doc.: IEEE 802.15-15-06-0018-00-003c
Submission
Challenge #1: Neighbor Discovery
• Different Tx/Rx antenna modes could be used at PHY layer
• Three types of neighbors– Omni-omni neighbors
– Directional-omni neighbors
– Directional-directional neighbors
January, 2006
Chun-Ting Chou, PhilipsSlide 9
doc.: IEEE 802.15-15-06-0018-00-003c
Submission
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
January, 2006
Chun-Ting Chou, PhilipsSlide 10
doc.: IEEE 802.15-15-06-0018-00-003c
Submission
Challenge #2: New Hidden-node Problems
• The Cause: Deafness– Asymmetry in Tx/Rx antenna gains
– Directional Transmission/Reception
CTSRTS
DATA
RTS
A B
A does not knowthe transmission
of B and vice versa
A
B does not know the
transmission between A and
Rx
Rx
Rx
Rx1
Rx2
B
B
Many other Cases !!
January, 2006
Chun-Ting Chou, PhilipsSlide 11
doc.: IEEE 802.15-15-06-0018-00-003c
Submission
Challenge #3: Spatial Reuse
• A by-product of directional transmission and reception
• 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)
A
B
Rx2
January, 2006
Chun-Ting Chou, PhilipsSlide 12
doc.: IEEE 802.15-15-06-0018-00-003c
Submission
Challenge #3: Spatial Reuse (conti.)
• A non-trivial problem– Hidden node problems (challenge #2)– Longer interference range
• Potential Solutions– Use directional network allocation vector
(D-NAV) in distributed networks
Rx2A RX1B RX2 B A Rx1
(a) Interference-free concurrent transmissions
(b) Interfering concurrent transmissions
January, 2006
Chun-Ting Chou, PhilipsSlide 13
doc.: IEEE 802.15-15-06-0018-00-003c
Submission
Challenge #3: Spatial Reuse (conti.)
– Use space-time scheduling in centralized networks
– Antenna gain/power control• without control
• with control
Rx2B Rx1A
directional-directional neighbors
Rx2B Rx1A
No interference
Receive interference
from B
Concurrent directional
transmission
January, 2006
Chun-Ting Chou, PhilipsSlide 14
doc.: IEEE 802.15-15-06-0018-00-003c
Submission
Issues of existing IEEE 802.15.3 MAC
January, 2006
Chun-Ting Chou, PhilipsSlide 15
doc.: IEEE 802.15-15-06-0018-00-003c
Submission
Existing IEEE 15.3 MAC
• Omni-omni neighbor is assumed
• Contention- and polling-based channel mechanism are both used
Superframe # m-1 Superframe # m+1
Channel time allocation periodBeacon
# m
Contention
access period
MCTA 1 MCTA 2 CTA 1 CTA 2 CTA n
Superframe # m
…
Piconet controller/devicesassociation via broadcasting beacons (neighbor discovery)
CSMA/CA medium access Control for control messages)
Scheduled transmission in channel time allocated by piconet controller
Challenge # 1 Challenge # 2 Challenges # 2 and 3
January, 2006
Chun-Ting Chou, PhilipsSlide 16
doc.: IEEE 802.15-15-06-0018-00-003c
Submission
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?
January, 2006
Chun-Ting Chou, PhilipsSlide 17
doc.: IEEE 802.15-15-06-0018-00-003c
Submission
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 MobiHoc, 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 MobiHoc, 2003