The document discusses using high frequency wireless technologies like 60GHz and 70/80GHz for fiber optic system (FSO) backup links for broadband connectivity. These frequencies have advantages like large bandwidth and avoidance of interference from other RF transmissions. While they face challenges from rain fade, 60GHz is presented as more cost-effective than 70/80GHz for links up to 1km when used to provide backup to an FSO system. Hybrid FSO/RF systems using SONAbeam FSO and 60GHz or 70/80GHz RF are proposed to provide highly available broadband connectivity over distances from 400m to 1500m.

1. High Capacity Broadband Wireless Connecting the IP/Ethernet/MPLS network of the future

4. SONAbeam FSO Attenuation in Heavy Rain: - much less than EHF Rain Attenuation – ITU Rain Zone K ‘ One Size Fits All’ for all the U.S. (except the Gulf Coast 1 ) 5-9s Rain Availability 1 (5 min outage/yr) 100 mm/hr FSO: 20 dB/km 3 60-90 GHz: 36 dB/km 2 4-9s Rain Availability (1 hr outage/yr) 42 mm/hr FSO: 8 dB/km 60-90 GHz: 18 dB/km 2 1. 5-9s rain rate for Region K is same as 4-9s for Gulf Coast, Region N 2. FCC Bulletin No.70, 33 dB/km; experimental data indicate this understates rain atten 3. SONAbeam rain performance validated in Costa Rica, rain region P, to 135 mm/hr

6. 5-9s Availability: SONABeam/60 GHz 99.999% Availability; OC-12 and GigE Links SONAbeam 1250-M with 60 GHz RF Backup ITU-R Rain Region (mm/hr rate) FSO range Heavy fog 60 GHz range In rain FSO range In rain 60 GHz range Heavy fog SONAbeam FSO/60 GHz 5-9s Avail. D: 42 mm/hr 400m 680m 2800m 1300m 1300m E: 70 mm/hr 400m 560m 1900m 1300m 1300m K: 100 mm/hr 400m 480m 1450m 1300m 1300m M: 120 mm/hr 400m 400m 1280m 1300m 1280m N: 180 mm/hr 400m 320m 950m 1300m 950m

7. 5-9s Availability: SONABeam/70-80 GHz 99.999% Availability; OC-12 and GigE Links SONAbeam 1250-M with 70/80 GHz RF Backup ITU-R Rain Region (mm/hr rate) FSO range Heavy fog 74-84 GHz In rain FSO range In rain 74-84 GHz Heavy fog SONAbeam FSO/70-80 5-9s Avail. D: 42 mm/hr 400m 880m 2800m 3500m 2800m E: 70 mm/hr 400m 760m 1900m 3500m 1900m K: 100 mm/hr 400m 680m 1450m 3500m 1450m M: 120 mm/hr 400m 600m 1280m 3500m 1280m N: 180 mm/hr 400m 520m 950m 3500m 950m

10. Frequencies & Wavelengths

13. Link Considerations