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March ,

BY ELECTRONIC FILING Marlene H. Dortch, Secretary Federal Communications Commission

th Street SW Washington, DC

Re: Ex Parte Notification for ET Dockets - and - .

Dear Ms. Dortch,

On March , , Chris Szymanski, Thomas Derham, and Gabriel Desjardins of Broadcom Inc. and I met with Dr. Monisha Ghosh, FCC Chief Technology Officer, as well as Ron Repasi, Bahman Badipour, Michael Ha, Nicholas Oros, Barbara Pavon, Hugh Van Tuyl, and Aole Wilkins El of the FCC’s Office of Engineering and Technology.

We discussed Broadcom’s laboratory testing of a camera-back radio widely used for

GHz electronic newsgathering (“ENG”) operations. Broadcom engineers transmitted broadcaster-recommended audio and video test patterns that required approximately megabits per second to an ENG receiver at various received signal levels (RSL). At each RSL, RLAN noise was injected at various duty cycles until any one of the following occurred: ( ) there was an audible defect in the signal; ( ) there was a visual defect in the signal; or ( ) the bit error rate (BER) increased above e- . In each case, however, BER exceeded e- before any audio or video degradation was observed. In fact, we did not observe any such degradation until the test signal reached a BER significantly greater than e- , e.g. e- . e test duration at each setting was sufficient for the equipment to appropriately determine the BER of the ENG signal. is testing was conducted over a period of days.

ese tests confirm that ENG receivers can operate without degradation or disruption

even in the presence of unrealistically high levels of RLAN interference. Even at the th percentile RLAN duty cycle1 we found that a typical ENG link configuration requires a signal-to-

1 See CableLabs, 6 GHz Low Power Indoor (LPI) Wi-Fi / Fixed Service Coexistence Study, 16 (2019) as attached to Letter from Rob Alderfer, Vice President of Tech. Policy, CableLabs, to

interference-plus-noise radio (“SINR”) of only dB to transmit an HD video stream without any degradation or disruption.

Pursuant to the FCC’s rules, I have filed a copy of this notice electronically in the dockets

referenced above.

Sincerely,

Paul Caritj Counsel for Broadcom Inc.

cc: meeting participants

Marlene Dortch, Sec’y, FCC, ET Docket No. 18-295 (filed Dec. 20, 2019); Broadcom, Duty Cycle Data, as attached to Letter from Paul Margie, Counsel, RLAN Group, to Marlene Dortch, Sec’y, FCC, ET Docket No. 18-295 (filed Dec. 9, 2019). This RLAN duty cycle was derived from Wi-Fi 6E waveforms produced using a signal generator transmitting continuously for a period of time, and then silent for another period of time. For a nearly continuous signal the ‘on’ period was 668 microseconds and the ‘off’ period was 50 microseconds. For a 10% duty cycle, the ‘on’ period was 224 microseconds and the ‘off’ period was 2000 microseconds. For a 2% duty cycle, the ‘on’ period was 72 microseconds and the ‘off’ period was 3500 microseconds. For a 1% duty cycle, the ‘on’ period was 52 microseconds and the ‘off’ period was 5000 microseconds. The SINR here is ratio of signal-to-interference-plus-noise, during ‘on’ periods when the RLAN interference is active.

Executive Summary

● Broadcom tested the potential impact of RLAN (Wi-Fi 6E) operation on 6 GHz ENG camera-back radio○ ENG configuration was based on our understanding of the ideal camera configuration in the

field (14 dBm conducted Tx power, 10 MHz channel, ⅚ or ⅞ code rate).○ Testing characterized blocker performance of ENG transceivers at various duty cycles.○ Testing allowed us to then analytically determine the impact of Wi-Fi 6E signals in scenarios

referenced in NAB filing.

● Results indicate that camera-back ENG radio links are robust and will perform well, even in the presence of unrealistically high levels of interference○ A 10 MHz ENG receiver can meet 1e-8 bit error rate (BER) at:

– 0 dB SINR at typical RLAN duty cycles (1 - 2%)– 5 dB SINR at 99th percentile RLAN duty cycle (10%)– 10 dB SINR at nearly continuous interference signal (93% transmission time)

Setup Diagram

ENG Tx +14 dBmIMT CP2-PRO-HD (Campac2 Transmitter)

6 GHz Signal GeneratorKeysight N5182B +N5182BX07

CombinerPasternackPE2026

Block Down Converter70DR2-BDC

Nucomm Newscaster DR1/DR2 TV Rx70NCDR2-HD-D-4D

Diagnostic TelevisionPanasonicBT-LH1700WP

AttenuatorKeysightJ7211A

● ENG system transmitted an HD video test pattern● Keysight signal generator created a valid Wi-Fi 6E signal● Wi-Fi 6E signal level for SINR calculation calibrated by transmitting

a CW signal with the TV Tx turned off○ The diagnostic television was used to measure the signal level

from the Nucomm Rx● Near-continuous Wi-Fi 6E waveform was loaded into signal

generator; also repeated at 1%, 2%, and 10% duty cycles

ENG Test Matrix

● ENG SINR performance was measured across a broad set of parameters○ 8 MHz and 10 MHz channels○ ¾, ⅚ and ⅞ coding rates○ ENG Rx powers from ~ -77 dBm to ~ -30

dBm

● Wi-Fi 6E signal power was adjusted at each measurement point until ENG BER > 1e-8 or the TV test pattern showed visual/audible artifacts

● Required SINR, as in the ABERT/SET1 study, was approximately constant at most received signal levels, with some deviation close to the ENG Rx sensitivity level

1 - http://set.org.br/tecnologia/testing.pdf

ENG Receiver Desense Measurements

● Required ENG SINR levels are shown below● Test Pattern signal requires fixed data rate

○ 10 MHz bandwidth requires less SINR than 8 MHz bandwidth at the same code rate– 10 MHz uses LMS-T format vs DVB-T for 8 MHz– LMS-T has better blocker performance than DVB-T

Required SINR (dB)

Wi-Fi 6E Duty Cycle 1% 2% 10%Near Continuous

(93%)ENG Code Rate 3/4 5/6 7/8 3/4 5/6 7/8 3/4 5/6 7/8 3/4 5/6 7/8ENG 8 MHz BW 1 4 5 3 5 7 7 8 9 10 14 15ENG 10 MHz BW -3 -2 0 -2 -1 1 2 4 5 6 7 10

ENG Receiver Desense Measurements (Continuous WLAN)

● ENG desense measurements were conducted across an RSL range of ~ -77 dBm to ~ -30 dBm

● Except at very low RSLs (< -72 dBm), the minimum SINR requirement for each configuration is approximately constant, i.e. independent of the RSL value○ At very low RSLs, the minimum

SINR requirement for each configuration increases

ENG Receiver Desense Measurements (10%/1% Duty Cycle)

● When the ENG desense measurements are repeated using typical RLAN duty cycles, the minimum SINR required in every configuration is substantially reduced○ For example, with 1% RLAN duty cycle, the more robust ENG configurations perform ideally even when the

RLAN signal strength (during an ON period) is similar to the wanted ENG RSL (i.e. 0 dB SINR), even when the RSL is very low

● Our testing clearly demonstrates that ENG camera-back radios will perform well even in the presence of unrealistically high levels of interference from RLAN devices.

● Even if an RLAN were somehow able to operate a nearly continuous transmission, only 10 dB in SINR is required

● In the presence of a Wi-Fi 6E access point operating at 10% duty cycle (99thpercentile), only 5 dB SINR is required to achieve broadcaster’s desired performance levels for a 10 MHz channel

● Typical Wi-Fi 6E duty cycles of less than 2% would require less than 1 dB in SINR in a typical configuration

Conclusion

Appendix

Prior Work

● Final Report on the Comparative Trials of the Digital Television Systems1○ Associação Brasileira das Emissoras de Rádio e Televisão (ABERT) and Sociedade Brasileira de

Engenharia de Televisão (SET) conducted testing of DVB-T radio performance from 1998-2000 for Brazilian regulator Anatel

○ Section 4.5 of this document outlines blocker testing methodology for TV equipment○ For the specific equipment used in this study, a 6 MHz DTV channel with 16-QAM modulation and ¾

coding rate required 19 dB C/N for error-free operation at most received signal levels● ETSI TR 101 190 V1.1.1 (1997-12): Digital Video Broadcasting (DVB); Implementation guidelines for DVB

terrestrial services; Transmission aspects2○ Figure 4/p. 19 shows theoretical estimates of 8 MHz DTV channel blocker performance under different

fading conditions (Rician modeling rooftop antennas)

1 - http://set.org.br/tecnologia/testing.pdf2 - https://www.etsi.org/deliver/etsi_tr/101100_101199/101190/01.01.01_60/tr_101190v010101p.pdf

Theoretical C/N Required for Error-Free Transmission (Rician Channel)Coding Rate 3/4 5/6 7/8

Required C/N (dB) 13 14 15

Thank You