NRUWiFi Coexistence in 56 GHz bands Cable Labs
NR-U/Wi-Fi Coexistence in 5/6 GHz bands Cable. Labs, Comcast, Cox Communications, Midco © Cable. Labs 2018 – Confidential. Do not share this material with anyone other than Cable. Labs' Member Employees.
Unlicensed Spectrum Growth: 5 GHz Band (United States, Current) 802. 11 channels UNII-1 UNII-2 a UNII-2 b 5470 5150 5250 5350 MHz MHz Available Channels UNII-2 c UNII-3 UNII-4 5925 5825 5725 MHz MHz Not Yet Available § 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. 11 ac/ax/be, LAA, NR-U, DSRC, and C-V 2 X may all share this spectrum 2 MHz
Unlicensed Spectrum Growth: 6 GHz 5925 MHz UNII-5 59 x 20 MHz 29 x 40 MHz 14 x 80 MHz 7 x 160 MHz 40 80 160 202020 20 40 40 80 80 20 20 40 40 80 80 202020 20 40 40 80 80 20 20 40 UNII-6 160 5925 MHz – 6425 MHz 24 x 20 MHz 12 x 40 MHz 6 x 80 MHz 3 x 160 MHz 20 20 40 40 80 7125 MHz 6425 MHz 202020 20 40 40 80 80 160 20 20 40 40 80 80 160 202020 20 40 40 80 UNII-8 UNII-7 20 20 40 40 40 80 160 80 40 20 20 40 40 40 202020 20 40 40 80 80 160 202020 20 20 40 40 80 80 160 Under discussion: § US 1. 2 GHz § EU 500 MHz 160 § 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 3 GPP 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 3
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. 4
DRAFT FOR DISCUSSION Cable WI-FI Footprint* Sample Operators Wi-Fi APs Altice USA (NY Tri-State) > 2, 000 Comcast (US) > 19, 000 Liberty Global (Europe) 12, 000 Shaw (Western Canada) > 100, 000 Charter Communications (US) > 250, 000 Total Sample (Member) Public APs (2018) > 33. 35 M Estimated Total (Public & Private) Member APs (2018) ~135 M Cable. Labs members: § Collectively serve more than 135 Million high-speed data subscribers § Wi-Fi supports personal, small, business communications, entertainment, Io. T. *Source: Company websites, Cable. Labs 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. 11 ac based, they are in course of transitioning to 802. 11 ax (5/6 GHz) by 2025. 5
LTE Offload on Wi-Fi networks Mobile Traffic Offloaded to Wi-Fi (%) § Wi-Fi Offload provides over 3/4 th 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. 6
3 GPP – 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 RAN 5…” “…RAN Chair: 3 GPP is totally open to such interaction and collaboration…” LS exchanges § The LS exchanged between IEEE and 3 GPP, on LAA LTE and NR-U, failed to address multiple points of contention. Certification/Test Programs § RAN 4 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 3 GPP and IEEE continue the unlicensed bands standard developments, without a minimal synchronization: § The Wi-Fi (802. 11 ac/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. 7 * 3 GPP LAA-1509, “Report of 3 GPP RAN workshop on Licensed-Assisted Access (LAA)”, Beijing, 08/29/2015
LTE LAA: The Unique Energy Detection (ED) Wi-Fi Energy Detection (ED) Threshold -62 d. Bm Wi-Fi is dominant* over the air interface LTE Energy Detection (ED) Threshold -72 d. Bm LTE is dominant over* the air interface Wi-Fi Preamble Detection (PD) Threshold -82 d. Bm The actual 3 GPP NR-U specifications trend may drive to the same type of unique ED concept. * As a result of LBT when the other access technology is detected 8
The ED Threshold Coexistence Challenge (1/2) 5 GHz public outdoor Wi-Fi Network* - 17, 410 APs (one of the largest US East Coast Cities) 5 GHz subway Wi-Fi network* - 3, 761 APs (one of the largest European capitals) -72 d. Bm RSSI Distribution (AP UL Rx RSSI d. Bm) RSSI CDF Distribution (AP UL Rx RSSI d. Bm) § The indoor subway traffic* peak (8 am) occurs @ -75 d. Bm § The RSSI CDF reflects the local geography (>250 subway stations) § 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 The outdoor UL traffic* peak occurs @ -87 d. Bm * Data acquired by Cable. Labs members 9
The ED Threshold Coexistence Challenge (2/2) An ED threshold at -72 d. Bm 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: § § § * Data acquired by Cable. Labs members 10 A fair interface access probability It is environment agnostic Support for hidden node detection by providing a dynamic PD (e. g. 802. 11 ax case) § PD could be detected in the presence of elevated noise (unlike ED). § PD provides potential power savings, since the transmission duration is known
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. 11
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