Frequency Allocations and Emerging Applications in the 50 to 70 GHz bands PART 1: PROPAGATION

1. Frequency Allocations and Emerging Applications in the 50 to 70 GHz bandsPART 1: PROPAGATION Luc Boucher Wireless and Internetworking SystemsExperimentation LABoratory Terrestrial Wireless Systems Branch (VPTWS) Communications Research Centre (CRC) / Industry Canada (IC) Study Sponsored by IC/Spectrum Engineering, CRC and Harris Fixed Wireless Communications Committee meeting, Sub-committee C, December 16, 1999

2. OVERVIEW OF PRESENTATION • Frequency Allocations and Emerging Applications in the 50 to 70 GHz bands • Characteristics of the millimeter wave channel and technical considerations • Overview of the 50-70 GHz millimeter wave band allocations and usage in various countries • Applications of the 50-70 GHz millimeter wave frequencies + products in development • Research and development in various countries & Conclusions

3. “Millimeter Wave Propagation: Spectrum Management Implications” FCC - OET Bulletin No. 70 (July 1997), see: http://www.fcc.gov/oet/info/documents/bulletins/#70 (paper copy distributed) Various ITU Reports: Recommendation ITU-R P.676-3: “Attenuation by atmospheric gases” ITU-R Rec. P.530-7: “Propagation data and precipitation methods required for the design of terrestrial line-of-sight systems” Recommendation ITU-R P.840-3: “Attenuation due to Clouds and Fog” ITU-R Rec. PN.837-1: “Characteristics of Precipitation for Propagation Modelling” ITU-R Recommendation P.1238 (1997): “Propagation data and prediction models for the planning of indoor radiocommunication systems and radio local area networks in the frequency range 900 Mhz to 100 GHz” Recommendation ITU-R P.833-2: “Attenuation in Vegetation” PROPAGATION AND TECHNICAL CONSIDERATIONSReferences

4. Free Space Loss increases significantly as the frequency increases: Propagation losses at millimeter wave frequencies are significantly larger than at lower frequencies This results from the dependence of free space loss on the square of the radio frequency See Figure 1, page 3 of Bulletin Number 70 Free Space Loss increases with frequency

5. Comparative table of Free Space Loss vs Frequency Distance = 2 km

6. When atmospheric effects are included, the losses can become even greater A major effect is due to the resonance of molecular oxygen and water vapor present in the Earth's atmosphere These produce high propagation loss in the mmw band near the frequencies of 60, and 118 GHz, for Oxygen, and 22.2, 183.3, and 325 GHz (among others) for Water. For example, at normal sea level air pressure, the 60 GHz oxygen resonance produces over 15 dB of loss per Km Figure 3, page 5 of Bulletin Number 70 Atmospheric Effects

7. Since rain drops are comparable in size to the wavelength of mmw signals, they are particularly good at absorbing mmw signals Rain attenuation is generally larger at higher mmw frequencies, and increases with the rate of rain fall Figure 10, page 13 of Bulletin Number 70 It should be noted that very high rain rates occur, in many countries, only for a very short time of the year, and are limited in their coverage (1 - 2 km) To appreciate the weather effects, it is not enough to know their relative magnitudes. It is necessary to know also the frequency of their occurrence and their duration These parameters are needed to determine the fade margin required to establish a system % availability (e.g, 99.99 % availability or .01 % total outage time = 52.6 minutes of total outage in a year) Precipitation / Hydrometeor

8. Attenuation by Dry Snow = about the same as by rain, for values of equivalent rain rate Since snowfall rates are usually less than an equivalent rate rate of 10 mm/h (which is a moderate rainfall), the effect of snow is generally less severe than rain Exception = wet snow = effect more severe than for equivalent rain rate Fog = close to drizzle (.25 mm/h) for frequencies below 150 GHz See combined figure of CCIR reports 719-3 and 664-1 Precipitation / Hydrometeor (cont.)

9. Foliage Losses • Foliage losses at mmw frequencies are significant • May be a limiting factor in some cases • See Rec. ITU-R P.833-2: “Attenuation in Vegetation” and page 14 of Bulletin Number 70 • Examples:

10. Scattering: The small wavelength of mmw signals produces additional losses due to scattering, when compared to lower frequencies. The effect is more pronounced at smaller wavelengths: surfaces that appear smooth at longer wavelengths (and therefore provide good mirror-like reflections) loose that characteristic at mmw frequencies Diffraction: The ability of radio waves to bend around obstacles, is also much less efficient at mmw frequencies. The effect of shadowing, where signals are blocked by a building, hill or other large structure, is therefore more pronounced Depending on the length of the link, multipath can also be a problem Other Impairments

11. The propagation characteristics of the mmw band can be in fact as much a benefit as a drawback This is because some communications systems can make use of the characteristics to enhance security and provide for significantly greater frequency re-use efficiency The working range of a 60 GHz fixed service link, for example, is about 2 km, and the channel can be used on another link (co-channel) as little as 4 km away without concern for interference By contrast, at 55 GHz, the working range is about 5 km, but a second link would have to be located about 18 km away to avoid co-channel interference. Figure 9, page 12 of Bulletin Number 70 Other factors must also be considered, e.g, antenna directivity, obstacle, etc. Drawbacks vs Benefits

12. ITU - Radio Regulations Article S5 - Frequency allocations (binding to its signatories) Frequency allocation tables updated at WRC (World Radiocommunication Conferences) National spectrum management administrations can use frequencies inconsistently with the ITU Radio Regulations, if they avoid interference to other countries The growing trend => international harmonization => facilitate international trade ITU Region 2 (Americas and Greenland) Frequency Allocation Table available at http://www.ero.dk/scripts/basmec/frqedw.dll/top International Table of Frequency Allocations

13. Canadian Table of frequency Allocations http://strategis.ic.gc.ca/SSG/sf01608e.html National Frequency Tables for various European countries http://www.ero.dk/eroweb/tables.html European Table of Frequency Allocations - CEPT/ERC Report 25 http://www.ero.dk/doc98/official/pdf/rep025.pdf (see paper copy distributed - Report 25, e.g., pp. 58 ) Report 25 = Harmonization of the spectrum in Europe - currently up to 105 GHz (harmonized by 2008) + have established a committee to look above 105 GHz (more later) Australian Radiofrequency spectrum planhttp://www.austel.gov.au/frequency/arsp99.pdf Table of Frequency Allocation available on the web

14. Frequency Allocation Table of Japanhttp://www.mpt.go.jp/policyreports/english/misc/table-e.html United Kingdom Frequency Allocation Table http://www.radio.gov.uk/document/rad_spec/ukalloc.htm United States Frequency Allocation Table available from the FCC Rules: See file “ 47cfr2.pdf ” at web address: http://www.fcc.gov/Bureaus/Engineering_Technology/Documents/cfr/1998/ or the NTIA Red Book, Chapter 4 http://www.ntia.doc.gov/osmhome/redbook/redbook.html Table of Frequency Allocation available on the web (cont.)