NR-U/Wi-Fi Coexistence in 5/6 GHz bands

1. NR-U/Wi-Fi Coexistence in 5/6 GHz bands

2. Unlicensed Spectrum Growth: 5 GHz 5 GHz Band (United States, Current) • FCC is set to propose an expansion of unlicensed access into the 5.9 GHz band • The entire 5 GHz band is being considered for enhanced global access (WRC-19) • Coexistence is crucial: 802.11ac/ax/be, LAA, NR-U, DSRC, and C-V2X may all share this spectrum UNII-1 5470 MHz 5825 MHz 5250 MHz 5725 MHz 5150 MHz 5350 MHz 802.11 channels UNII-4 UNII-2b UNII-3 UNII-2a UNII-2c 5925 MHz Not Yet Available Available Channels

3. Unlicensed Spectrum Growth: 6 GHz 7125 MHz 5925 MHz 6425 MHz • Both US and Europe are considering to open significant license-exempt bandwidth in the 6 GHz range • 6 GHz is critical to expand the Gbps broadband access to the residential environments • IEEE and 3GPP technology will populate this band, both expected to operate in the context of: i) existing incumbent users and ii) equal air time access probability • Coexistence is as critical in 6 GHz as in the 5 GHz UNII-5 UNII-8 UNII-6 UNII-7 24 x 20 MHz 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 12 x 40 MHz 40 40 40 40 40 40 40 40 40 40 40 40 6 x 80 MHz 80 80 80 80 80 80 3 x 160 MHz 160 160 160 5925 MHz – 6425 MHz • Under discussion: • US 1.2 GHz • EU 500 MHz 59 x 20 MHz 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 29 x 40 MHz 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 14 x 80 MHz 80 80 80 80 80 80 80 80 80 80 80 80 80 80 7 x 160 MHz 160 160 160 160 160 160 160

4. DRAFT FOR DISCUSSION Wi-Fi Remains a Broadband Workhorse Source: Cisco VNI Global IP Traffic Forecast, 2017-2022 By 2022: Wi-Fi networks will carry more than 50% of total global IP traffic and nearly 80% of total global IP wireless traffic Wi-Fi networks will remain the workhorse of personal wireless access technology for the foreseeable future.

5. DRAFT FOR DISCUSSION Cable WI-FI Footprint* • CableLabs members: • Collectively serve more than 135 Million high-speed data subscribers • Wi-Fi supports personal, small, business communications, entertainment, IoT. *Source: Company websites, CableLabs member data • No wireless access technology intended for the unlicensed spectra (5/6 GHz) could be defined without considering Wi-Fi. • While these APs are mainly 802.11ac based, they are in course of transitioning to 802.11ax (5/6 GHz) by 2025.

6. LTE Offload on Wi-Fi networks Mobile Traffic Offloaded to Wi-Fi (%) • Wi-Fi Offload provides over 3/4th of total data consumed through mobile devices. • A sub-optimal LAA LTE/NR coexistence with Wi-Fi will degrade the mobile to Wi-Fi offloading.

7. 3GPP – IEEE Communications. Lessons Learned. Goodwill • between the two SDOs during the LTE LAA workshop in 2015*: “... IEEE: would like to see a collaboration to be established between the coexistence group of IEEE 802 and RAN5…” “…RAN Chair: 3GPP is totally open to such interaction and collaboration…” LS exchanges • The LS exchanged between IEEE and 3GPP, on LAA LTE and NR-U, failed to address multiple points of contention. Certification/Test Programs • RAN4 LTE LAA coexistence testing specifications remained optional. • WFA LTE LAA coexistence testing specifications didn’t get a cross industry (mobile-fixed) traction. Agreement on the LTE LAA fairness criterion for coexistence (5 GHz) • However no such criterion was agreed on for the 6 GHz band. Should 3GPP and IEEE continue the unlicensed bands standard developments, without a minimal synchronization: • The Wi-Fi (802.11ac/ax) and LTE LAA/NR-U equipment rolled out in the field may mutually degrade their end-user experience performance. • As the last resort, this may require the intervention of the regulatory bodies. * 3GPP LAA-1509, “Report of 3GPP RAN workshop on Licensed-Assisted Access (LAA)”, Beijing, 08/29/2015

8. LTE LAA: The Unique Energy Detection (ED) The actual 3GPP NR-U specifications trend may drive to the same type of unique ED concept. Wi-Fi Energy Detection (ED) Threshold -62 dBm Wi-Fi is dominant* over the air interface LTE Energy Detection (ED) Threshold -72 dBm LTE is dominant over* the air interface Wi-Fi Preamble Detection (PD) Threshold -82 dBm * As a result of LBT when the other access technology is detected

9. The ED Threshold Coexistence Challenge (1/2) 5 GHz subway Wi-Fi network* - 3,761 APs (one of the largest European capitals) 5 GHz public outdoor Wi-Fi Network* - 17,410 APs (one of the largest US East Coast Cities) -72 dBm -72 dBm RSSI Distribution (AP UL Rx RSSI dBm) RSSI CDF Distribution (AP UL Rx RSSI dBm) • The indoor subway traffic* peak (8am) occurs @ -75dBm • The RSSI CDF reflects the local geography (>250 subway stations) The outdoor UL traffic* peak occurs @ -87dBm • A unique ED threshold can’t address multiple types of coexistent traffic (e.g. outdoor, office, subway etc.) • An optimal coexistence scenario would require a RSSI distribution agnostic solution * Data acquired by CableLabs members

10. The ED Threshold Coexistence Challenge (2/2) • An ED threshold at -72 dBm would block: • 92% of the outdoor Wi-Fi traffic* • 54% of the subway Wi-Fi traffic* • The unique ED doesn’t support an optimal coexistence • A common preamble (e.g. 802.11) provides: • A fair air interface access probability • It is environment agnostic • Support for hidden node detection by providing a dynamic PD (e.g. 802.11ax case) • PD could be detected in the presence of elevated noise (unlike ED). • PD provides potential power savings, since the transmission duration is known * Data acquired by CableLabs members

11. Way Forward • Implement the 802.11 preamble on NR-U (5/6 GHz) • Specify a new fairness criterion for 6 GHz • Without a jointly agreed 6 GHz fairness criterion (e.g. equal air time access), the 6 GHz NR-U specs development would remain challenging. • Setup a small joint tiger team representing both SDOs to address the challenges impacting the existing and the future unlicensed bands.