Ka-band Frequencies for HTS

Most HTS typically file for 3.5 GHz bandwidth in the following Ka-bands:

27.5 – 31 GHz uplink

17.7 – 21.2 GHz downlink

As seen in Annex 1 this range of frequencies is subject to various regulatory procedures. One way to divide these bands is as follows:

a) Bands identified for High-Density FSS

RR No. 5.516B gives the bands identified for high-density fixed-satellite service (HDFSS). These bands allow for the deployment of uncoordinated FSS earth stations under a blanket license. The only bands that include all Regions are:

29.5 – 30 GHz (uplink)                  (500 MHz)

19.7 – 20.2 GHz (downlink)          (500 MHz)

On the downlink the following Regional identifications for HDFSS are made in RR No. 5.516B:

17.3-17.7 GHz       (space-to-Earth) in Region 1,

18.3-19.3 GHz       (space-to-Earth) in Region 2,

In Regions 1 and 3 the use of the band 17.3-18.1 GHz by geostationary-satellite systems in the fixed-satellite service (Earth-to-space) is limited to feeder links (i.e. Earth-to-space) for the broadcasting-satellite service (RR No. 5.516). However, in Region 1 the band 17.3-17.7 GHz (400 MHz) may also be used for FSS downlink provided that it does not claim protection from from the broadcasting-satellite service feeder-link earth stations. Nor shall it put any limitations or restrictions on the locations of the broadcasting-satellite service feeder-link earth stations anywhere within the service area of the feeder link (see RR No. 5.516A). This is not a serious restriction since there are a very limited number of BSS feeder link stations

b) Bands used by many administrations for FS including LMDS

In all three ITU Regions in most of the FSS Ka-band the FS is co-primary. Another band preferred for FSS is the 1.1 GHz band:

27.5 – 28.6 GHz

17.7 – 18.8 GHz

However, many administrations have services such as local multipoint distribution services (LMDS) in this band. This service does not share well with HDFSS.

c)  Bands where GSO and non-GSO satellite networks have equal rights

In general, from RR No. 22.2:

22.2 § 2  1)    Non-geostationary-satellite systems shall not cause unacceptable interference to and, unless otherwise specified in these Regulations, shall not claim protection from geostationary-satellite networks in the fixed-satellite service and the broadcasting-satellite service operating in accordance with these Regulations. No. 5.43A does not apply in this case. (WRC-07)

However, in the following two bands GSO and non-GSO satellite networks have equal rights:

a) 500 MHz band originally intended for Teledesic:

28.6– 29.1 GHz (uplink), 18.8 – 19.3 GHz (downlink)

The O3B non-GSO network is planned to operate in this band. The OB3 network does not suffer from the usual non-GSO disadvantages given above due the fact that the service area which is the area +/- 45° North and South latitude can be covered continuously by a relatively small constellation of initially 6 satellites in equatorial orbit. In addition, the service is not intended for direct delivery to consumers but for telecom operators who can afford the more expensive tracking antennas needed. The telecom operators will re-sell the service to consumers.

b) 400 MHz band for non-GSO feeder links (Iridium):

29.1 – 29.5 GHz, 19.3 – 19.7 GHz

Iridium operates in the L-band on the service link and in the Ka-band on the feeder link.

In the bands a) and b) above RR No. 9.11A applies which means that a new network whether GSO or non-GSO must coordinate with earlier filed GSO and non-GSO networks as well as other primary services operating in the band.

d) Bands where equivalent pfd (epfd) applies

The epfd limits were introduced by SkyBridge at WRC-97 and adopted by WRC-2000. The SkyBridge non-GSO satellite network was intended to operate in the Ku-band but WRC-2000 adopted epfd limits for portions of both the C-, Ku- and Ka-bands. Presently there are no satellites operating using this concept.

The concept is based on re-using GSO frequencies by a non-GSO constellation outside the GSO by avoiding the GSO by about +/- 10°. Annex 1 shows the Ka-bands that are subject to epfd (up and down) limits. These limits define the maximum permissible interference that non-GSO FSS systems can cause to GSO FSS networks. The epfd limits are given in Article 22 for different antenna sizes for different percentages of time. The epfd (up and down) values were calculated so that they would increase the unavailability by no more than 10% on the most sensitive links. The links used for this calculation were engineered to be very sensitive and did not represent typical links. Therefore, in reality, a non-GSO FSS system will cause even less than a 10% increase in unavailability on a GSO FSS link i.e. the values are so low that they will have a negligible effect on the GSO FSS links. 

E)  Military bands

Although they are not identified as such in the RR, the following bands are used by the military. 

30 – 31 GHz (uplink)

20.2 – 21.2 GHz (downlink)

It may be possible for a commercial operator to provide services to the military.  For example, the Ka-band payload of the Inmarsat Global Xpress™ satellites can be toggled back and forth between military and commercial frequencies. Each satellite will also carry multiple steerable beams capable of directing capacity in real time to the location where it is needed. This capability has been incorporated with the military in mind for use that includes unmanned aerial vehicles (UAV). Inmarsat hopes to sell services to the military. A few administrations will not allow commercial operators to file for the military bands.

⇐ Предыдущая1234Следующая ⇒

Поделиться: