1. Proposed Evaluation Methodology Additions
January 2010
doc.: IEEE /1160r3
January 2010
Proposed Evaluation Methodology Additions
Date:
Authors:
John R. Barr, JRBarr, Ltd.
John R. Barr, JRBarr, Ltd.

2. January 2010
doc.: IEEE /1160r3
January 2010
Abstract
Proposed update to TGad Evaluation Methodology to include declaration of how coexistence requirements from TGad PAR and Functional Requirements are handled. Goal is to best protect TGad systems from other 60GHz systems and ensure that TGad does not interfere with those systems.
John R. Barr, JRBarr, Ltd.
John R. Barr, JRBarr, Ltd.

3. TGad Coexistence Requirements
January 2010
TGad Coexistence Requirements
From the TGad PAR:
It is in the best interest of users and the industry to strive for a level of coexistence between wireless systems. VHT will investigate coexistence with other systems in the 60 GHz band.
One approach will be to investigate a common PHY between VHT and c, and adopt if feasible.
Another approach is a common coexistence mechanism that may be used by other 60 GHz systems
From TGad Functional Requirements:
[Req08] The system is required to support mechanisms that enable coexistence with other systems in the band including IEEE c systems.
John R. Barr, JRBarr, Ltd.

4. 60 GHz Coexistence Assumptions
January 2010
60 GHz Coexistence Assumptions
TGad will use same channel frequencies as c, ECMA-387, and WirelessHD; and avoid using a channel that is “occupied”.
c systems using a channel will broadcast superframe beacons/sync frames using CMS at least once every 66mS identifying the piconet and when channel will be used during each superframe.
c, ECMA-387, and WirelessHD devices transmit without LBT in a variety of modulation modes when CTA allocated for their use. (TDMA MAC)
John R. Barr, JRBarr, Ltd.

5. Possible Coexistence Mechanisms (1)
January 2010
Possible Coexistence Mechanisms (1)
Prior to starting a BSS, scan target channel for at least 100mS (or some other time larger than 66mS) for presence of other 60GHz traffic and only use channels that are free.
Can use energy detection or preamble detection (20dB gain).
If capable of receiving and decoding c beacons or sync frames, a BSS may be established in the same channel as long as transmissions are only scheduled during CAP or other open periods for each superframe.
Requires support for c CMS and ability to decode beacon or sync frame (similar formats) by all stations.
John R. Barr, JRBarr, Ltd.

6. CMS Detection versus Energy Detection
Nov 2009
CMS Detection versus Energy Detection
CMS preamble detection requires
-83 dBm received signal power.
In systems, energy detection requires 20 dB more received energy level than that of carrier sense, therefore -63dBm is required.
Results: 5m distance case
Energy detection probability is only 5%
While CMS detection probability is 95%
Energy Detection
Proabability 5% for 5m
CMS Detection
Probability 95% for 5m
Tuncer Baykas, NICT.

7. Possible Coexistence Mechanisms (2)
January 2010
Possible Coexistence Mechanisms (2)
If AP is capable of joining an c piconet as a child piconet, it can allocate private time during each superframe and only schedule TGad channel availability during that time.
Requires support of c CMS and limited set of c MAC commands by the AP.
Non-AP devices only need to be able to listen to AP beacons and schedule transmissions during the allocated time.
John R. Barr, JRBarr, Ltd.

8. January 2010
IEEE c Coexistence
All IEEE c implementations are required to use defined coexistence methods:
All PNC capable DEVs shall transmit beacons or sync frames using CMS in every superframe.
All PNC capable DEVs shall receive sync frames and command frames transmitted using CMS.
A DEV scans all available channels prior to starting a piconet to determine which channels are free of other piconets and have least amount of other noise.
A DEV shall not start an independent piconet in a channel that is not clear.
An c PHY must be able to detect CMS beacons or sync frames within a 10m range (NLOS).
John R. Barr, JRBarr, Ltd.

9. Evaluation Criteria (1)
January 2010
Evaluation Criteria (1)
Proposal has ability to avoid channels occupied by c and other 60GHz radio systems:
Add clause to section 2 for FR Req08:
2.3 Detection of Other 60GHz Systems for Coexistence (FR 2.3 Req08)
Should provide synthetic test case to demonstrate compliance with requirements in [functional requirements section 2.3].
Single AP ready to establish BSS
One c piconet controller sending CMS beacon/sync frame every 66mS
Distance between AP and piconet controller no less than 5m
PHY channel corresponds to Home Living Room, Office Conference Room, OR Enterprise Cubicle
Detection probability must be greater than 90%
John R. Barr, JRBarr, Ltd.

10. Evaluation Criteria (2)
January 2010
doc.: IEEE /1160r3
January 2010
Evaluation Criteria (2)
Add clause to section 4 for Coexistence Detection
4.5 Coexistence Detection
Should provide probability of detection of c system operation
Should provide probability of detection of proposed TGad system operation by c device (looking for CMS preamble)
c CMS preamble as defined in IEEE c-2009
1760 Mchip/s, π/2 BPSK/precoded (G)MSK (clause )
ECMA-387 preamble defined in ECMA-387 may be added as an additional level of detection
John R. Barr, JRBarr, Ltd.
John R. Barr, JRBarr, Ltd.

11. January 2010
Summary
Although other coexistence methods defined in c provide additional levels of channel sharing, simple detect and avoid channel scanning will best serve TGad implementation.
IEEE Std c-2009 systems will avoid other systems that transmit pre-defined sync frames within 10m range.
Use of common preambles provides a higher level of detection than energy detection (20dB).
The proposals adopting “a higher level of detection” should be evaluated as “having better co-existence capability”
John R. Barr, JRBarr, Ltd.

12. References January 2010 11-09-1108-00-00ad-tg-docs-open-items.ppt
doc.: IEEE /1160r3
January 2010
References
ad-tg-docs-open-items.ppt
ad-evaluation-methodology.doc
ad-functional-requirements.doc
vht-60-ghz-par-nescom-form-plus-5cs.doc
ad-response-to c.ppt
ad-common-mode-signaling-cms-for-intersystem-coexistence-enhancement.ppt
ad-tg3c-dev-sync-frame-transmission-for-adjacent-piconet-coexistence.ppt
ad-topology-considerations-on-contention-based-directional-mac-simulation.ppt
ad-wirelesshd-coexistence.ppt
ad-Energy-Dectection-vs-Common-Mode-Signaling-Detection-for-Coexistence.ppt
IEEE Std c™-2009
ECMA-387
John R. Barr, JRBarr, Ltd.
John R. Barr, JRBarr, Ltd.