1. doc.:IEEE 802.11-11-0160-01-00m Submission January 2011 11n Spectrum Mask Alignment Date: 2011-01-19 Slide 1 Authors: Bijoy Bhukania, Broadcom

2. doc.:IEEE 802.11-11-0160-01-00m Submission January 2011 Summary 5 GHz Spectral mask floor in 11n is misaligned with that of 11a and 11ac –11n mask is -45 dBr, while 11a and 11ac mask is -40 dBr We propose to align the 11n mask specification with that of 11a and 11ac –Only for 5 GHz band –No spectral mask floor changes proposed for 2.4 GHz Impact of this change is evaluated –Impact on transmit power –Impact of SINR of a adjacent receiver –Overall impact on network performance Slide 2Bijoy Bhukania, Broadcom

3. doc.:IEEE 802.11-11-0160-01-00m Submission January 2011 Mask Observations Slide 3 11a, 11ac spec Existing 11n spec Bijoy Bhukania, Broadcom

4. doc.:IEEE 802.11-11-0160-01-00m Submission January 2011 Issues with Different Specifications for 11n and 11ac A 11ac device, when transmitting a 11n frame, has to comply with 11n specification –No reason to have different SM for 11n and 11ac Existing 11a networks are working with -40 dBr mask –No real need to have 11n specification of -45 dBr, at least in 5 GHz band A stricter mask limits the transmit power of lower MCS –SM limit is reached first. –Limits range Slide 4Bijoy Bhukania, Broadcom

5. doc.:IEEE 802.11-11-0160-01-00m Submission January 2011 Impact of SM on Transmit Power The plots are based on 11a/n/ac Rapp model The SM “slope” comes from nonlinearity, while the floor comes from noise Transmit power of 11n devices is limited by the -45 dBr floor -40 dBr spec would allow transmitter to transmit up to 4 dB higher power Slide 5Bijoy Bhukania, Broadcom

6. doc.:IEEE 802.11-11-0160-01-00m Submission January 2011 Impact on EVM -18 dB EVM does not degrade PER performance of MCS0 –EVM of -18 dB is attained at 4 dB back-off from P1 dB point –But -45 dBr SM is violated, but -40 dBr is not Slide 6Bijoy Bhukania, Broadcom

7. doc.:IEEE 802.11-11-0160-01-00m Submission January 2011 Impact on SINR at an Alternate Adjacent Receiver Additional degradation in SINR due to -40 dBr SM is 2.91 dB for worst- case AACI levels. –Not 5 dB as reported in Nov’2010 IEEE meeting This is due to the noise level being accounted for Slide 7Bijoy Bhukania, Broadcom

8. doc.:IEEE 802.11-11-0160-01-00m Submission January 2011 Overall Benefits of -40 dBr Specification Transmit power for lower MCS can be increased by up to 4 dB –Leads to increased range, bigger BSS, and reduced infrastructure cost AACI level increase is not significant –SINR for worst-case AACI levels degrades by 2.91 dB (-50 dBm AACI power), while for the -70 dBm AACI power case AACI level degrades by marginal 0.07 dB. –“Range” in absence of AACI increases significantly Slide 8Bijoy Bhukania, Broadcom

9. doc.:IEEE 802.11-11-0160-01-00m Submission January 2011 Some Concerns Raised in 1/19/2011 REVmb Meeting ETSI mask is stricter –Actually ETSI mask level is at -40 dBr up to 9x BW Same -40 dBr is proposed here Interference to radar problem –Problem is more pronounced at the band edge, i.e. start of the mask skirt ( about -22 dBr) -40 vs -45 dBr mask level is less of an issue here –FCC may define xy dBm/MHz requirement (current discussions), not finalized AACI –Not as pronounced, in the 0-3 dB range, depending on scenarios

10. doc.:IEEE 802.11-11-0160-01-00m Submission January 2011 Conclusion TX spectral mask should be modified from -45 dBr to -40 dBr for several strong reasons: –Significant range enhancement in normal operating scenario Important for 5 GHz band since no CCK rates are used –Whole home coverage –Marginally enhanced range in presence of AACI –Reduced infrastructure cost –Uniformity between 11a, 11n and 11ac specifications Slide 10Bijoy Bhukania, Broadcom

11. doc.:IEEE 802.11-11-0160-01-00m Submission January 2011 Straw Poll #1 Only for 5 GHz band, do you support aligning the 11n spectral mask specifications with 11a and 11ac, which would require modifying the 11n mask level from -45 dBr to -40 dBr? –Yes: –No: –Abstain: Slide 11Bijoy Bhukania, Broadcom