frequency sharing study between fwa & fss in the band 5725 - 5875 mhz david bryant wireless...

Frequency Sharing Study between FWA & FSS in the band

5725 - 5875 MHz

David BryantWireless Networks

Presentation to UK W-LAN Advisory Group(Sharing & DFS sub-group)9th December 2002

© British Telecommunications plc, 2002 2

Sharing Studies performed Aggregate effect of FWA terminals radiating into

representative FSS satellite receivers

- INTELSAT IX (31.5o West) > 5850 MHz only

- Statsionar Express (14o West) - whole band

- INTELSAT VII (66o East) > 5850 MHz only

Effect of FSS earth station transmissions on FWA receivers

FWA: Mesh & Point-to-Multipoint systems considered

Sharing Scenario for FSS Earth-to-space Satellite Links sharing with FWA (e.g.Mesh or P-MP) networks in the 5725-

5875 MHz frequency band

FSS Satellite

FSS Earth Station

Wanted signal pathsInterference signal paths

Uplink FSS path

FWAOutdoor Terminals

GSO Orbit

Minimum elevation ~4 degrees

5GHz ‘Band C’ Spectrum Allocations

* Short range indoor data links + CCTV + movement detectors max 25 mW eirp.** Road Transport & Traffic Telematics.

RR Allocation

s

Frequency (MHz)57505725

Other service

s(UK &

Europe)5775 5825 5850

ISM

RADIOLOCATION Amateur

5875

Fixed Satellite Service (R1)(Earth-to-space)

FSMOBILE

SRDs* SRDs

FSS (Global)(Earth-to-

space)

5800

FS (Footnotes 5.453, 5.455, 5.456) Not UKLand Mobile (UK) (Footnote 5.451)

5795

5815

RTTT**

Fixed & transportable video links

UK nominalchannel

allocationsfor FWA

(under discussion)

20 MHz channel spacing

O/B(Max eirp 40 dBW, 20 MHz BW)

Parameter Value Source

Maximum mean EIRP 1 Watt ETSI TR 102 079

On-axis gain 10 dBi “

Off-axis gain envelope(gain @ elevation angle)

-25 dBi @ 60o-90o

-15 dBi @ 40o-60o

“

Off-axis gain (0o –40o) See Figure European AntennasVertical Omni

Mounting Roof-top -

Bandwidth 22 MHz ETSI TR 102 079

Radio Access TDD/TDMA “

Modulation OFDM “

Polarisation Linear (vertical) “

Peak-to-average power 6 dB “

Total Tx activity/node 5% “

Rx sensitivity (lowest) -78 dBm “

C/I 11 “

Maximum tolerableinterference

-89 dBm -

Table of ETSI FWA Mesh Radio Parameters for use in FSS Sharing Studies

UK draft spec in IR2006 is 2 Watts

Table of ETSI FWA PMP Radio Parameters for use in FSS Sharing Studies

Parameter Base Station Subscriber Terminal Source

Maximum peak EIRP 1 Watt 1 Watt ETSI TR 102 079

Reduction due toAutomatic Power Control

5 dB 5 dB “

On-axis gain 15 dBi 18 dBi “

Off-axis gain envelope(gain @ elevation angle)

See Figure See Figure European AntennasSectoral & Flat-plate

Mounting 0o elevation Some of these are mountedunder eaves, and indoors

ETSI TR 102 079

Bandwidth 22 MHz 22 MHz “

Radio Access TDD/TDMA TDD/TDMA “

Modulation OFDM OFDM “

Polarisation Linear (vertical) Linear (vertical) “

Duty ratio 60% 3% “

Rx sensitivity (mean) -88 dBm -85 dBm “


Calculation of interference into satellite link

%xT

T

link

link

. . . . . . . . . . . . (1)

where,Tlink : apparent increase in the equivalent satellite link noisetemperature due to an interfering emission (K);

Tlink : the equivalent satellite link noise temperature (K)

x = 1%, 6% & 10%

• Standard method (used in satellite inter-coordination)


Calculation of interference into satellite link(cont.)

• Gr , l : fairly insensitive to FWA location (in N.W. Europe)

• , Gr , Tlink : obtained from Satellite Advanced Filing Information(this should lead to conservative results)

• Work out maximum aggregate EIRP tolerable from FWA systems


Elevation Plane Radiation Patterns for FWA Antennas at 5.8 GHz

Mesh Antenna:

Source: www.european-antennas.co.uk

http://www.european-antennas.co.uk/





Elevation Plane Radiation Patterns for FWA Antennas at 5.8 GHz

Point-to-MultipointSubscriber Unit Antenna

Point-to-MultipointBase StationSectoral Antenna

Source: www.european-antennas.co.uk





Blue ring shows points where an FWA terminal or base station antenna would subtend an elevation angle of 20o to the Region 1 Statsionar Express Satellite in Geostationary Orbit at 14o West longitude

(global beam not shown)

Blue ring shows points where an FWA terminal or base station antenna would subtend an elevation angle of 5o to the INTELSAT VII satellite (IS-704) in Geostationary Orbit at 66o East longitude (uplink hemi-beam

also shown)(N.B. this satellite only operates in the portion of the band above 5850 MHz)


Maximum No. of FWA devices deployable

39

,21

0,8

11

6,5

35

,13

5

9,0

32

,64

6

5,4

19

,58

8

90

3,2

65

1,8

06

,52

9,1

83

1,0

83

,91

7,5

10

18

0,6

52

,91

8

65

,35

1,3

51

10,000

100,000

1,000,000

10,000,000

100,000,000

1,000,000,000

10,000,000,000

10 6 1

Increase in Satellite Link Noise Temperature due to FWA Emissions (%)

No

. o

f F

WA

De

vic

es

pe

rmit

ted

FWA Mesh (ETSI spec.)

FWA PMP cells

FWA PMP Subscriber Units

Satellite: Statsionar Express 2 @ 14o WestRange of elevation angles from the UK: 23o-33o


Maximum No. of FWA devices deployableSatellite: INTELSAT IX @ 31.5o West (>5850 MHz only)

Range of elevation angles from the UK: 20o-28o

11,7

04

,04

4

1,9

50

,67

4

99

5,1

69

59

7,1

01

99

,51

7

19

9,0

33

,77

2

119

,42

0,2

63

19

,90

3,3

77

19

,50

6,7

39

10,000

100,000

1,000,000

10,000,000

100,000,000

1,000,000,000

10 6 1


No

. o

f F

WA

De

vic

es

pe

rmit

ted


FWA PMP cells



Maximum No. of FWA devices deployableSatellite: INTELSAT VII @ 66o East (>5850 MHz only)

Range of elevation angles from the UK: 4o-7o

64

,28

9

10

,71

5

16

,18

3

9,7

10

1,6

18

3,2

36

,58

8

1,9

41

,95

3

32

3,6

59

10

7,1

49

1

10

100

1,000

10,000

100,000

1,000,000

10,000,000

10 6 1


No

. o

f F

WA

De

vic

es

pe

rmit

ted


FWA PMP cells



Effect of aggregate interference on C/I of FSS carrier

Real example, UK - Hong Kong satellite circuit via 66o

East Satellite C/Nup = 22.7 dB;

C/Ndown = 15.52 dB;

C/Nintermod = 30 dB;

C/Nother interference = 27 dB;

Gives at the distant receiving earth station, C/Ntotal = 14.4 dB;

Wanted carrier bandwidth: 27 MHz

When the effects of the FWA interference are included, i.e.,

EIRPFWA in bandwidth of 20 MHz = 33.5 dBW for Tlink/Tlink = 10%

Wanted earth station uplink EIRP (in bandwidth of 27 MHz) = 76.8 dBW

C/IFWA = 43.3 dB

Hence, the aggregate effect of the FWA devices has a quite negligible impact on the qualityof the satellite circuit.

• Single example but T/T of 10% doesn’t seem too onerous

Locations where an FWA Mesh receiver could suffer excessive (Long-term) interference in the band 5850 – 5875 MHz fromEarth station transmissions at Martlesham Teleport Earth Station in East Anglia

(Earth station antenna pointing towards ISVII satellite at 66o East longitude; 10 km NGR grid overlay))The calculations use Rec. ITU-R P.452 to show areas (in red) where a mesh antenna located 8 metres above ground level could receive excessively high interference for 20% of the time due to

emissions from the MTP-10 antenna with an assumed transmit power into the antenna feed flange of 24 dBW. The yellow area is the reduced area in which interference would occur for a 15 dB increase in coupling loss (e.g. due to additional clutter loss along the path).


Conclusions

Sharing between the FSS and FWA systems appears favourable in the band 5725 - 5850 MHz

- This is mainly due to the directional properties of FWA antennas in the elevation plane.

Top 25 MHz of Band C (5850-5875 MHz) is slightly less favourable:

- Because of the low elevation angles subtended into N.W. Europe by some satellites close to the horizon.

frequency sharing study between fwa & fss in the band 5725 - 5875 mhz david bryant wireless...

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