doc.: IEEE /559r0 Submission May 2009 Minyoung Park, Intel Corp.Slide 1 Analysis on IEEE c coexistence scheme Date: Authors:

doc.: IEEE /559r0 Submission May 2009 Minyoung Park, Intel Corp.Slide 2 Abstract The following presentation analyzes the CMS (common mode signaling) Sync Frame based coexistence scheme of c.

doc.: IEEE /559r0 Submission May 2009 Minyoung Park, Intel Corp.Slide c Coexistence c has following rules to promote coexistence among devices using different PHYs (based on the presentation 09/0370r2 [1]): –“The below rules on CMS usage are specified in the TG3c draft: An AV or an HSI PNC shall send a CMS sync frame in every superframe An AV or an HSI PNC shall be able to receive the CMS sync frame An SC PNC shall send CMS beacon in every superframe All SC DEV shall be able to send and receive signal in CMS –The specified rules indicate that all PHY modes are able to communicate with / detect each other using a commonly supported signaling scheme –Any new PNC seeking to start a piconet, shall initially perform channel scan. Upon receiving CMS beacon/sync frame from an already-active PNC, this new PNC will be aware of its existence and shall avoid interfering signal transmission” Only PNCs are mandated to support CMS sync frame but not DEVs –Not all DEVs can communicate with or detect others

doc.: IEEE /559r0 Submission May 2009 Minyoung Park, Intel Corp.Slide c Coexistence - Example Two overlapping piconets using different PHYs can coexist only if PNCs can hear each other’s CMS sync frame PNC1 (PHY1/CMS) DEV2 PNC2 (PHY2/CMS) DEV3 PNCs are within each other’s transmission range DEV1DEV4 PHY1 PHY2 Piconet 1 (PHY1)Piconet 2 (PHY2)

doc.: IEEE /559r0 Submission May 2009 Minyoung Park, Intel Corp.Slide c Coexistence Problem DEVs may interfere with each other if PNCs cannot hear each other’s CMS sync frame –PNCs out of transmission range –Large signal attenuation due to obstacles –Low antenna gain toward each other due to unfavorable antenna orientation Sync frame is optional feature for DEVs PNC1 (PHY1/CMS) DEV2 PNC2 (PHY2/CMS) Piconet 1 (PHY1)Piconet 2 (PHY2) PHY1 PHY2 PNCs are out of each other’s transmission range DEV1 DEV3 DEV4

doc.: IEEE /559r0 Submission May 2009 Minyoung Park, Intel Corp.Slide 6 Simulation Setup Matlab (ray tracing) Room configuration –Dimension (LxWxH) 6m x 12m x 3m –5 specular reflectors/piconet random location 2dB reflection loss PNC –Number of antennas = 1 patch antenna element (random orientation) –Transmit power = 10 dBm –Noise Figure=8 dB –Implementation loss=2 dB 6m PNC1PNC2 d m 12m 1m 3m Radiation pattern of a single patch antenna (peak gain ~ 3dBi) reflector Patch antenna

doc.: IEEE /559r0 Submission May 2009 Minyoung Park, Intel Corp.Slide 7 CMS Transmission Range Define CMS transmission range with 10% outage probability = Prob (SNR<7dB*) = 0.1 SNR distribution –CMS transmission range ~ 10m 6m PNC1PNC2 d m 12m 1m 3m reflector 7 dB *) SNR threshold 7dB from 09/0370r2[1]

doc.: IEEE /559r0 Submission May 2009 Minyoung Park, Intel Corp.Slide 8 Interference between Two Piconets 6m Tx range ~10m PNC1PNC2 d > 10 m DEV1 DEV2 DEV3 DEV4 12m D m Tow piconets using same channel DEV configuration –Heavy load traffic (e.g. wireless display) –1 antenna element case –16 antenna element case SINR degradation –1 antenna case: > ~5dB –16 antenna case: > ~10dB 10 dB 5 dB

doc.: IEEE /559r0 Submission May 2009 Minyoung Park, Intel Corp.Slide 9 Office Cubicle Environment Cubicle configuration –Dimension (LxWxH): 2.5m x 1.8m x 3m –5 specular reflectors/piconet (random location, 2dB reflection loss) –Partition wall: 3dB penetration loss CMS transmission range –10% outage prob. Prob(SNR<7dB) = 0.1 –Transmission range ~ 5m 1.8m PNC1PNC2 d m 2.5 m.5m.9m Office partition Penetration loss ~3dB 7 dB

doc.: IEEE /559r0 Submission May 2009 Minyoung Park, Intel Corp.Slide 10 Interference between Two Piconets Three piconets using same channel DEV configuration –Heavy load traffic (e.g. wireless display) –1 antenna element case –16 antenna element case SINR degradation –SINR measured at Piconet2 –1 antenna case: ~7dB –16 antenna case: ~12 dB 12 dB 7 dB 1.8m PNC1PNC2 2.5 m PNC3 Piconet1Piconet2 Piconet3 DEV1 DEV2 DEV3 DEV4 DEV5DEV6 ch#1 ch#2 ch#3 Channel number

doc.: IEEE /559r0 Submission May 2009 Minyoung Park, Intel Corp.Slide 11 10m Assume CMS sync frame can reach multiple cubicles Multiple piconets must share the time resource –reduces throughput/piconet Multiple piconets have to coordinate their schedules –Below example: 5 piconets operating in the same channel –Hard to achieve stable schedules (especially when one piconet has dynamic traffic) Problem of a Long CMS Transmission Range in a Dense Office Cubicle Environment Tx range ~ 10m PNC Channel number m

doc.: IEEE /559r0 Submission May 2009 Minyoung Park, Intel Corp.Slide 12 Conclusions c’s CMS sync frame based coexistence scheme is analyzed –CMS sync frame scheme works only when PNCs are within each other’s CMS transmission range –If the PNCs are out of each other’s transmission range, the DEVs start to interfere with each other –A long CMS transmission range may cause schedule instability problem It is a hard problem to address the coexistence between the networks using different PHYs

doc.: IEEE /559r0 Submission May 2009 Minyoung Park, Intel Corp.Slide 13 References [1] Common mode signaling (CMS) for intersystem coexistence enhancement, 09/0370r2, Shu Kato09/0370r2