AU6250400A

AU6250400A - Apparatus and method for reusing satellite broadcast spectrum for terrestrially broadcast signals

Info

Publication number: AU6250400A
Application number: AU62504/00A
Authority: AU
Inventors: Carmen Tawil; Saleem Tawil
Original assignee: Northpoint Technology Ltd
Current assignee: Northpoint Technology Ltd
Priority date: 1996-10-11
Filing date: 2000-10-05
Publication date: 2000-12-07
Anticipated expiration: 2017-10-09
Also published as: AU762929B2

Description

AUSTRALIA

Patents Act 1952 COMPLETE SPECIFICATION FOR A STANDARD PATENT

(ORIGINAL)

Name of Applicant: Actual Inventor(s): Address for Service: Invention Title: Northpoint Technology, Ltd Carmen Tawil Saleem Tawil DAVIES COLLISON CAVE, Patent Attorneys, 1 Little Collins Street, Melbourne, 3000.

Apparatus and method for reusing satellite broadcast spectrum for terrestrially broadcast signals o oooo oooo oooo oo The following statement is a full description of this invention, including the best method of performing it known to me/us: IP Austraiia ffi OCT 2000 Balgsh NoL Q:\OPER\KATn721537div.doc 5/10/00 lA APPARATUS AND METHOD FOR REUSING SATELLITE

BROADCAST

SPECTRUM FOR TERRESTRIALLY BROADCAST

SIGNALS

BACKGROUND OF 'EIIE INVENTION This invention relates to apparatus and methods for broadcasting and receiving data, including digital television signals and voice signals. More particularly, this invention relates to an apparatus and method for providing terrestrial transmissions simultaneously along with direct broadcast satellite transmissions on a common frequency.

Currently, television signals may be received from a satellite in geosynchronous orbit about the earth. The television signals are transmitted from a terrestrial transmitter to the satellite and then retransmitted from the satellite so that the signals can be received by terrestrial receivers within a certain geographic receiving area within a line of sight of the satellite. In addition to television signals, other types of data may also be transmitted to consumers through satellites in geosynchronous orbit.

Direct broadcast satellite service (DBS) refers to satellite transmission of television signals directly for use by individual households or subscribers having the proper signal receiving equipment. The U.S. Federal Communications Commission has dedicated the electromagnetic spectrum from 12.2 gigahertz to 12.7 gigahertz for DBS broadcasting.

20 Sixteen signal carriers are located within the DIIS spectrum, each carrier carrying several individual television channels. Depending upon the compression technology applied to these signals, literally hundreds of separate channels may be available through DBS. A great benefit of the DBS system as opposed to prior satellite systems is that only a small dish-type antenna is required to receive the DBS signals and the alignment of the receiving dish is not critical. Also, the DBS system will provide high quality reception at any point in the geographic receiving area of a satellite without the expense of land transmission lines such as those required for cable television.

Current regulations require tiat )BS satellites be separated from each other by at least nine degrees in a geosynchronous arc. The receiving antenna for DBS signals must, therefore, be limited to receiving signals in a directional range measuring plus or minus nine degrees from a centerline of the antenna. Receiving signals in a range P:\OPERUAT\721537div.d-O5/110/00 -2wider than the satellite spacing would cause interference by signals transmitted by different satellites on the same frequency.

U.S. Patent No. 5,483,663 is directed to a system having a receiver arrangement in which DBS and terrestrial signals are received within similar frequency bands. The system shown in the 5,483,663 Patent may be implemented with a multiple antenna arrangement, or with a single, moveable antenna. In the multiple antenna arrangement, two separate antennas direct the received signals to a common propagation path for processing as if they were received by a single antenna and transmitted from a single location. In the single antenna arrangement, the antenna is moveable between a position to receive DBS signals and another position to receive terrestrial signals.

The advantage of the system shown in U.S. Patent No. 5,483,663 is that local originating signals, whether television signals or other data, may be received simultaneously with DBS signals, and processed with the same equipment as that used to process the DBS signals. The local originating signals may carry local programming which S°15 may be received along with the national or regional DBS programming.

However, since the signals received in the system shown in U.S. Patent No.

S 5,483,663 are combined or received on the same antenna structure at different points in time, terrestrial and DBS signals cannot be received simultaneously on a common frequency.

Despite the advantages of DBS and the advantages of the system shown in U.S.

Patent No. 5,483,663, the DBS system ties up a portion of the electromagnetic spectrum which would otherwise be available for terrestrial signal transmissions.

SUMMARY OF THE INVENTION According to the present invention, there is provided an apparatus for simultaneously transmitting terrestrial signals on a common frequency with satellite signals transmitted from a satellite, the satellite transmitting satellite signals at a first frequency to a user location for reception only within a satellite directional reception range about the user location, the apparatus comprising: P:\OPER\KA'I72I1537divdc-05/10/00 -3a directional terrestrial transmitter for transmitting terrestrial signals at the first frequency in a limited azimuth range around the location of the terrestrial transmitter, the terrestrial transmitter being located with respect to the user location such that the terrestrial transmitter transmits to the user location along a route which is outside of the satellite directional reception range.

The invention also provides a method for simultaneously providing terrestrial signals on a common frequency with satellite signals transmitted from a satellite, where the satellite is transmitting at a first frequency along a satellite transmission axis extending from the satellite to a terrestrial user location, the method comprising the steps of: transmitting terrestrial signals at the first frequency in a limited azimuth range from a terrestrial transmitter, the terrestrial transmitter being located with respect to the user location so as to transmit to the user location along a transmission route which is outside of a satellite directional reception range about the user location, wherein the satellite directional reception range comprises a limited directional range substantially S" 15 centred on the satellite transmission axis.

The invention further provides an apparatus for facilitating the use of terrestrial transmitted signals which are transmitted on a common frequency simultaneously with satellite signals transmitted from a satellite, the satellite transmitting satellite signals at a first frequency to a terrestrial user location along a satellite transmission axis, the apparatus 20 comprising: a terrestrial transmitter for transmitting terrestrial signals at the first frequency to the user location, the terrestrial transmitter being located with respect to the user location such that the terrestrial transmitter transmits to the user location along a route which is outside of a satellite directional reception range about the user location, wherein the satellite directional reception range comprises a limited directional range substantially centred on the satellite transmission axis; and a terrestrial receiving antenna at the user location for receiving signals at the first frequency only within a terrestrial directional reception range about a centerline of the terrestrial antenna, the terrestrial antenna being aligned to receive signals transmitted at the P.:\OPERKAT721537div.do-05/I0/00 -3Afirst frequency from the terrestrial transmitter location, and being aligned so that the satellite transmission axis is outside of the terrestrial directional reception range.

The invention further provides an apparatus for simultaneously transmitting terrestrial signals on a common frequency with satellite signals transmitted from a satellite, the satellite transmitting satellite signals at a first frequency to a user location for reception only within a satellite directional reception range about the user location, the apparatus comprising: a terrestrial transmitter for transmitting terrestrial signals at the first frequency from a fixed terrestrial location which forms a fixed geometry with the user location and the satellite, the terrestrial transmitter being located with respect to the user location such that the terrestrial transmitter transmits to the user location along a route which is outside of the satellite directional reception range about the user location.

The invention further provides an apparatus for simultaneously providing terrestrially transmitted signals on a common frequency with direct broadcast satellite 15 signals transmitted from a satellite in a first satellite location in geosynchronous orbit about the earth, the apparatus comprising: a first antenna at a user location for receiving signals at a first frequency only within a first directional reception range as measured from a centerline of the first antenna, the first antenna having its centerline aligned to receive direct broadcast satellite 20 signals transmitted from the satellite; eooeo a second antenna at the user location for receiving signals at the first frequency only within a second directional reception range as measured from a centerline So of the second antenna, the second antenna being aligned to receive signals transmitted at the first frequency from a terrestrial transmitter location remote from the user location with the direct broadcast satellite signals transmitted in directions outside of the second directional reception range; and a terrestrial transmitter for transmitting signals at the first frequency and directionally within a terrestrial azimuth range from the terrestrial transmitter location, the terrestrial transmitter location being located with respect to the user location such that the P:\OPERTAT\721537div.doc-05/10 -3Bterrestrial transmitter transmits in directions only outside of the directional reception range of the first antenna.

The invention still further provides a method for simultaneously providing local originating signals on a common frequency with direct broadcast satellite signals transmitted from a satellite, where the satellite is in a first satellite location in geosynchronous orbit about the earth, the method comprising the steps of: at a user location, receiving direct broadcast satellite signals at a first frequency with a first antenna adapted to receive signals at the first frequency only within a first directional reception range as measured from a centerline of the first antenna; transmitting terrestrial signals at the first frequency and in a terrestrial azimuth range from a terrestrial transmitter, the terrestrial azimuth range being outside of :i the directional reception range of the first antenna positioned to receive direct broadcast satellite signals from the satellite; and at the user location, remote from the terrestrial transmitter, receiving the ee 15 terrestrial signals with a second antenna adapted for receiving signals at the first frequency only within a second directional reception range as measured from a centerline of the S second antenna, the second antenna being aligned so that the direct broadcast satellite signals transmitted by the satellite are not transmitted within the directional reception range of the second antenna.

The invention still further provides a method for providing simultaneously and on a common frequency direct broadcast signal from a satellite transmitter orbiting the earth and local originating signal from a terrestrial transmitter, in which the direct broadcast and local originating signals are received by respective first and second antennas at the same location, the directivity and orientation of the antennas with respect to the satellite and terrestrial transmitters being such that the first antenna does not receive substantial local originating signal and the second antenna does not receive substantial direct broadcast signal.

The invention still further provides a method of receiving simultaneously and on a common frequency direct broadcast signal from a satellite transmitter orbiting the earth and local originating signal from a terrestrial transmitter, in which the direct broadcast and

I

IP\OPERWAT1\721537div.d-05/I0/00 -3Clocal originating signals are received by respective first and second antennas at the same location, the directivity and orientation of the antennas with respect to the satellite and terrestrial transmitters being such that the first antenna does not receive local originating signal and the second antenna does not receive substantial direct broadcast signal.

The invention still further provides apparatus for receiving simultaneously and on a common frequency, at a location, direct broadcast signal from a satellite transmitter orbiting the earth, and local originating signal from a terrestrial transmitter, the apparatus having first and second antennas, at said location, the directivity and orientation of the antennas with respect to the satellite and terrestrial transmitters being such that, when said signals are being simultaneously transmitted, of those signals the first antenna receives substantially only the direct broadcast signal and the second antenna receives substantially ••only the local originating signal.

The invention still further provides apparatus for receiving simultaneously and on a common frequency, at a location, direct broadcast signal from a satellite transmitter 15 geosynchronously orbiting the earth, and local originating signal from a terrestrial transmitter, the apparatus having first and second antennas, at said location, the directivity S and orientation of the antennas with respect to the satellite and terrestrial transmitters being such that, when said signals are being simultaneously transmitted, of those signals the first antenna receives substantially only the direct broadcast signal and the second antenna receives substantially only the local originating signal.

The invention still further provides apparatus for receiving simultaneously and on a ::.":common frequency, at a location, direct broadcast signal from one of a plurality of satellite transmitters geosynchronously orbiting the earth, and local originating signal from a terrestrial transmitter, each of the satellite transmitters being arranged for transmission of a respective said broadcast signal on said common frequency, the apparatus having first and second antennas, at said location, the directivity and orientation of the antennas with respect to the satellite transmitters and the terrestrial transmitter being such that, when the direct broadcast signals from the satellite transmitters and the local originating signals are being simultaneously transmitted, of these signals the first antenna receives substantially P:\OPERKAT721537di.do-5110MO -3Donly the direct broadcast signal from said one satellite transmitter and the second antenna receives substantially only the local originating signal.

Embodiments of the invention provide terrestrially transmitted signals simultaneously with satellite transmitted signals at the same frequency. Embodiments of the invention include an apparatus and method for providing terrestrial and satellite signals simultaneously at a common frequency.

Embodiments of the invention utilize receiving antennas with a limited directional reception range and transmitting the terrestrial signals in a different range of directions than those in which the satellite signals are transmitted. Embodiments of the invention require two separate receiving antennas feeding two sets of decoding and demodulating processing systems for utilizing the received signals. Both receiving antennas may be adapted to receive signals only within a particular directional range. The range may be measured from a centerline of the particular antenna.

:In order to ensure no interference between the satellite and terrestrially transmitted 15 signals, the terrestrial signals may be transmitted directionally within a terrestrial azimuth range which is outside the azimuth range in which the satellite signals are transmitted either by a single satellite or multiple satellites. The terrestrial transmit azimuth range may be chosen so that it does not include any directions in which the satellite signal receiving antenna must be directed to receive signals from any satellite. In order to cover a large area for local reception, a plurality of terrestrial transmitters may be spread out over an area with directional transmitted areas overlapping to ensure the terrestrial signals may be received clearly at each location within the desired service area.

S" These and other objects, advantages, and features of the invention will be apparent from the following description of the preferred embodiments, considered along with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a schematic representation showing the positions of a plurality of satellites in relation to a single terrestrial transmitter and a receiver or user location.

P:\OPERXKATI721537div.doc05/10/00 -3E- FIGURE 2 is a somewhat schematic representation of a receiving antenna structure for receiving satellite and terrestrial transmitted signals at a common frequency.

FIGURE 3 is a schematic representation of the spacing for a number of terrestrial transmitters required to allow reception over a large geographic area.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The apparatus according to the invention for providing satellite and terrestrially transmitted signals simultaneously on the same frequency illustrated in FIGURES 1 and 2.

As shown in FIGURE 1, the system 10 may be utilized with one or more satellites in geosynchronous orbit about the earth. FIGURE 1 shows four satellites 12a, 12b, 12c, and 12d spaced apart at four separate directions from a user location 14. In geosynchronous orbit, each satellite remains at a fixed location with respect to the earth's surface, and thus, with respect to the user location 14. First and second antenna 16 and 18, ooo** respectively, which will be discussed in detail with reference to FIGURE 2 are located at the user location 14.

Each of these satellites 12a-d is positioned in geosynchronous orbit about the center of the earth, and is positioned at a certain longitude and latitude above the earth's surface.

As is known by those skilled in the art, a receiving antenna may be directed at a certain elevation and direction or azimuth toward a desired satellite location for receiving signals from the particular satellite.

Currently, all direct broadcast satellites within the line of sight of North America are positioned at longitudes and latitudes requiring the receiving antenna to face in a southerly direction from North America to receive signals. Although FIGURE 1 shows four satellites 12a-d for purposes of describing the invention herein, more or fewer satellites may be spaced apart within a line of sight of a certain geographical area. Eight satellites are currently within a line of sight of North America. Table 1 sets out the longitudinal location of each satellite and for purposes of example, the azimuth and elevation at which a receiving antenna must be directed from a location at Austin, Texas for receiving signals from each satellite. All azimuth directions and elevations are measured to a centerline of the antenna which will be discussed below with respect to FIGURE 2. The term "azimuth" refers to the direction with respect to a reference direction such as due north, commonly zero degrees. "Elevation" refers to the angle of the antenna centerline above horizontal.

TABLE I Satellite Longitude Azimuth Elevation 61.5 124.5 37.3 101 186.4 54.6 110 203.3 52.3 119 .217.7 47.8 148 247.3 25.7 157 253.3 17.9 166 258.8 10.1 175 263.5 2.3 seat 0 a 0.00 *5 0

S.

0S

S.

S

5.95 DBS satellites all transmit different signals in the same frequency band. The U.S.

Federal Communications Commission has set aside the electromagnetic spectrum from 12.2 gigahertz to 12.7 gigahertz for DBS broadcasting. In order to ensure no interference from signals between two adjacent satellites, two conditions must be met. First, the receiving antenna must he limited to receive signals only within a certain reception range about the centerline of the antenna. Secondly, the satellites must be spaced apart about the geosynchronous arc so that a receiving antenna may be positioned with only a single satellite transmitting in the directional reception range of the antenna.

According to current regulations, individual DBS satellites must be separated at least nine degrees in the geosynchronous arc. Thus, each DBS receiving antenna must have a directional reception range or aperture of plus or minus nine degrees or less as measured from a centerline of the antenna. Although current regulations require a spacing of no less than nine degrees separation, the invention is not limited to this degree of separation. However, according to the invention, the effective reception range of each first antenna or satellite reception antenna must be less than or equal to the minimum satellite separation angle.

FIGURE 1 also shows as terrestrial transmitter 20 capable of transmitting in one or more frequencies identical to a frequency transmitted by one of the DBS satellites. The terrestrial transmitter 20 transmits directionally within a certain transmission range T. The transmission range T shown in FIGURE 1 is 180 degrees, although the range may he more or less than this number.

The antenna structure 22 according to the invention at the user location 14 in FIGURE 1 is illustrated by way of example in FIGURE 2. The first antenna 16 is designed to receive direct broadcast satellite signals. The first antenna 16 includes a 000 a a a S 15 0 0 0 00 ~0 0

S

S0..

0000 *10 15 6 collecting dish 24 and a feed-horn assembly 26 for receiving the signals reflected and concentrated by the dish. Those skilled in the art will readily appreciate that the feed-horn assembly 26 includes a probe, which is not shown in FIGURE 2, for picking up the signal received by the antenna. The probe feeds the signal to signal processing equipment for extracting information from the received signal. This signal processing equipment is well known in the art and does not form a part of this invention. Also, those skilled in the art will appreciate that numerous types of assemblies may be used alternatively to the feedhorn assembly 26 for collecting signals reflected by the dish 24.

The first antenna 16 includes an antenna centerline 28. As dictated by the frequency of the signal received, the first antenna 16 has a maximum directional reception range d max. as measured from the antenna centerline 28. Signals propagating in a direction outside of this reception range or aperture about the antenna centerline 28 cannot be received by the first antenna 16.

Referring still to FIGURE 2, tihe antenna stnicture 22 at the user location 14 further includes the separate second antenna 18 for receiving tihe terrestrially transmitted signals.

The second antenna 18 is shown as a feed-horn type antenna, however, those skilled in the art will readily appreciate that the second antenna may include a circular wave guide antenna, flat plate antenna, slot antenna, dipole antenna or multi-dipole antenna.

Regardless of the antenna type, tIhe antenna will include a suitable signal pick-up assembly for picking up the signal received by the antenna and feeding the signal to suitable signal procesrocesing equipment. his processing equipment is separate from the processing equipment for processing the signals received by the first antenna 16. Also, although the second antenna 18 is shown connected to the same structure as the first antenna 16, the first and second antennas may be completely separate. In any event, the second antenna to to 18 is preferably rotatable about a vertical axis as shown at B in FIGURE 2 to direct the antenna for optimally receiving the terrestrial transmitted signals.

As with the first antenna 16, the second antenna 18 includes a centerline 30 and may receive signals travelling only within a dlirectional reception range r max. about the antenna centerline 30. Signals travelling in a direction outside that range cannot be received by the second antenna 18.

Referring again to FIGURE 1, the first antenna 16 according to the invention, is directed to receive signals from one of the satellites, satellite 12d for example. The azimuth and elevation at which the first antenna 16 must be directed for optimally receiving signals from satellite 12d may be 247.3 and 25.7 respectively, for example. 'Fle second antenna 18 is directed with its centerline 30 pointing generally to the terrestrial transmitting location of the terrestrial transmitter 20 and essentially horizontally. Ignoring the elevation difference between the first and second antennas 16 and 18, respectively, (Ile azimuth difference between the centerlines 28 andi 30 of the two antennas and this example is approximately 67.7 degrees.

In the orientation shown in FIGURE I, the first antenna 16 cannot receive signals from the terrestrial transmitter 20. The reason for this is that the directional signals transmitted fromn the terrestrial transmitter 20 are all travelling in a direction outside of thie reception range of the first antenna 16. Similarly, the direction in which the satellite 12d transmits with respect to the user location 14 is outside of the reception range of the second antenna 18. '[hus, thie second antenna 18 cannot receive signals transmitted by [lie satellite 12d. Furthermore, in this example, the second antenna 18 cannot receive any signals transmitted by anmy of the satellites 12a-d. Thus, in the orientation of the first and second antenna 16 and 18 as shown in FIGURE 1 and with the position of thie satellites 15 12a-d and terrestrial transmitter 20, the terrestrial transmitter may transmit on a frequency identical to the frequency of signals transmitted by the satellites without any interference in the signals received at the two antennas.

Those skilled in the art will readily appreciate that the elevation of the first antenna 16 may be high enough with respect to horizontal so that the second antenna 18 may be aligned along the same azimuth as the first antenna without any interference between the signals received by the two antennas on the identical frequency. However, where there are numerous satellites at different azimuths and elevations with respect to the user location 14, the first and second antennas 16 and 18 may have to be positioned at different azimuths as illustrated in FIGURE 1 in order to prevent interference.

Referring to FIGURE 3, a plurality of terrestrial transmitters 32 are required to provide a signal strong enough to be received over a large area. Each transmitter 32 in FIGURE 3 transmits directionally in an azimuth range A of approximately 180 degrees and out to an effective reception range R. With this transmitter spacing and transmission range, the signals from the terrestrial transmitters may be received from any location within the geographic area G. Although the directional range of 180 degrees is shown for purposes of example, the terrestrial transmissions may be in other ranges within the scope of this invention.

The method according to the invention comprises receiving satellite signals in a first frequency with the first antenna 16. The first antenna 16 is adapted to receive signals only within a first directional reception range from Ihe antenna centerline 28. The method also includes transmitting signals in the first frequency directionally in a range outside of the directional reception range of the first antenna 16. Signals transmitted by the terrestrial transmitter are received by the second antenna 18 at the user location 14. The second P:\OPERXA,'72I1537div.do-05/IOO -9antenna 18 is also adapted to receive signals only within a directional reception range with respect to the antenna centerline This combination of directional receiving antennas 16 and 18, and directional terrestrial transmission allows terrestrial transmissions at an identical frequency as that used by satellites, and particularly DBS without interference between the two transmissions. This allows the DBS spectrum and perhaps other satellite spectra to be reused for terrestrial transmissions. The terrestrial transmissions may be for television signals or any other data, including Internet communications, voice data, other video, or any other type of data.

10 The above described preferred embodiments are intended to illustrate the principles of the invention, but not to limit the scope of the invention. Various other embodiments and modifications to these preferred embodiments may be made by those skilled in the art o• without departing from the scope of the following claims.

Throughout this specification and the claims which follow, unless the context 15 requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that that prior art forms part of the common general knowledge in Australia.

Claims

1. An apparatus for simultaneously transmitting terrestrial signals on a common frequency with satellite signals transmitted from a satellite, the satellite transmitting satellite signals at a first frequency to a user location for reception only within a satellite directional reception range about the user location, the apparatus comprising: a directional terrestrial transmitter for transmitting terrestrial signals at the first frequency in a limited azimuth range around the location of the 10 terrestrial transmitter, the terrestrial transmitter being located with respect to the user location such that the terrestrial transmitter transmits to the user S" "location along a route which is outside of the satellite directional reception range. 15

2. The apparatus of Claim 1 wherein satellite signals are transmitted from a plurality of satellites in geosynchronous orbit, each satellite separated from each other satellite in a geosynchronous arc by an angle greater than one half of the satellite •coo directional reception range and the satellites together transmit satellite signals to the user location only within a combined satellite signal transmission range about the 20 user location, and wherein: the terrestrial transmitter transmits only in directions which are outside of the combined satellite signal transmission range and an angle equal to one half of the satellite directional reception range outside of the boundaries of the combined satellite signal transmission range.

3. The apparatus of Claim 2 further comprising: a plurality of terrestrial directional transmitters, each transmitting from a different terrestrial transmission location and each transmitting directionally in a limited azimuth range. P:\OPER\KAT,721537div.dc-05/IOA0 -11-

4. The apparatus of Claim 1 wherein the first frequency is in a range of 12.2 gigahertz to 12.7 gigahertz.

The apparatus of Claim 1 wherein the first frequency is above 12.2 gigahertz.

6. The apparatus of Claim 1 wherein the satellite directional reception range is approximately eighteen (18) degrees.

7. A method for simultaneously providing terrestrial signals on a common frequency 10 with satellite signals transmitted from a satellite, where the satellite is transmitting at a first frequency along a satellite transmission axis extending from the satellite to a terrestrial user location, the method comprising the steps of: o. o transmitting terrestrial signals at the first frequency in a limited azimuth range from a terrestrial transmitter, the terrestrial transmitter being located 15 with respect to the user location so as to transmit to the user location along a transmission route which is outside of a satellite directional reception range about the user location, wherein the satellite directional reception range comprises a limited directional range substantially centred on the satellite transmission axis.

8. The method of Claim 7 further comprising the step of: transmitting terrestrial signals at the first frequency and within a limited terrestrial azimuth range from a plurality of terrestrial transmitters at different locations.

9. The method of Claim 7 wherein the first frequency is in the range of 12.2 gigahertz to 12.7 gigahertz. The method of Claim 7 wherein the first frequency is above 12.2 gigahertz.

P:\OPERTATh721537divdoc-05/10O -12-

11. The method of Claim 7 wherein the satellite directional reception range is approximately eighteen (18) degrees.

12. An apparatus for facilitating the use of terrestrial transmitted signals which are transmitted on a common frequency simultaneously with satellite signals transmitted from a satellite, the satellite transmitting satellite signals at a first frequency to a terrestrial user location along a satellite transmission axis, the apparatus comprising: a terrestrial transmitter for transmitting terrestrial signals at the first 10 frequency to the user location, the terrestrial transmitter being located with respect to the user location such that the terrestrial transmitter transmits to the user location along a route which is outside of a satellite directional reception range about the user location, wherein the satellite directional reception range comprises a limited directional range substantially centred on the satellite transmission axis; and a terrestrial receiving antenna at the user location for receiving signals at the *seefirst frequency only within a terrestrial directional reception range about a centerline of the terrestrial antenna, the terrestrial antenna being aligned to receive signals transmitted at the first frequency from the terrestrial 20 transmitter location, and being aligned so that the satellite transmission axis 000000 is outside of the terrestrial directional reception range.

13. The apparatus of Claim 12 wherein satellite signals are transmitted from a plurality of satellites in geosynchronous orbit, each satellite separated from each other satellite in a geosynchronous arc by an angle greater than an angle equal to one half of the satellite directional reception range and the satellites together transmit satellite signals to the user location only within a combined satellite signal transmission range about the user location, and wherein: the terrestrial transmitter transmits only in directions which are outside of the combined satellite signal transmission range and an angle equal to one P:\OPERA721537div.doc-05/I1000 13- half of the satellite directional reception range outside of the boundaries of the combined satellite signal transmission range.

14. The apparatus of Claim 13 further comprising: a plurality of terrestrial transmitters each transmitting from a different terrestrial transmission location and each transmitting directionally in a limited azimuth range.

The apparatus of Claim 12 wherein the first frequency is in a range of 12.2 10 gigahertz to 12.7 gigahertz. .00.

16. The apparatus of Claim 12 wherein the first frequency is above 12.2 gigahertz. 0

17. The apparatus of Claim 12 wherein the satellite directional reception range is S 15 approximately eighteen (18) degrees. oo o

18. An apparatus for simultaneously transmitting terrestrial signals on a common frequency with satellite signals transmitted from a satellite, the satellite transmitting o: satellite signals at a first frequency to a user location for reception only within a 20 satellite directional reception range about the user location, the apparatus comprising: a terrestrial transmitter for transmitting terrestrial signals at the first frequency from a fixed terrestrial location which forms a fixed geometry with the user location and the satellite, the terrestrial transmitter being located with respect to the user location such that the terrestrial transmitter transmits to the user location along a route which is outside of the satellite directional reception range about the user location.

19. The apparatus of Claim 18 wherein satellite signals are transmitted from a plurality of satellites in geosynchronous orbit, each satellite separated from each other P M (UKATn72137div.docO 5/10,UO -14- satellite in a geosynchronous arc by an angle greater than one half of the satellite directional reception range and the satellites together transmit satellite signals to the user location only within a combined satellite signal transmission range about the user location, and wherein: the terrestrial transmitter transmits only in directions which are outside of the combined satellite signal transmission range and an angle equal to one half of the satellite directional reception range outside of the boundaries of the combined satellite signal transmission range. 10

20. The apparatus of Claim 18 further comprising: a plurality of terrestrial transmitters, each transmitting from a different fixed :terrestrial transmission location which forms a fixed geometry with the satellite and the user location.

21. The apparatus of Claim 18 wherein the first frequency is in a range of 12.2 gigahertz to 12.7 gigahertz.

22. The apparatus of Claim 18 wherein the first frequency is above 12.2 gigahertz.

23. The apparatus of Claim 18 wherein the satellite directional reception range is S "approximately eighteen (18) degrees.

24. An apparatus for simultaneously providing terrestrially transmitted signals on a common frequency with direct broadcast satellite signals transmitted from a satellite in a first satellite location in geosynchronous orbit about the earth, the apparatus comprising: a first antenna at a user location for receiving signals at a first frequency only within a first directional reception range as measured from a centerline of the first antenna, the first antenna having its centerline aligned to receive direct broadcast satellite signals transmitted from the satellite; P:\OPER\KA' \72137div.doc4-O5/IOA)O a second antenna at the user location for receiving signals at the first frequency only within a second directional reception range as measured from a centerline of the second antenna, the second antenna being aligned to receive signals transmitted at the first frequency from a terrestrial transmitter location remote from the user location with the direct broadcast satellite signals transmitted in directions outside of the second directional reception range; and a terrestrial transmitter for transmitting signals at the first frequency and directionally within a terrestrial azimuth range from the terrestrial 10 transmitter location, the terrestrial transmitter location being located with respect to the user location such that the terrestrial transmitter transmits in directions only outside of the directional reception range of the first antenna.

The apparatus of Claim 24 wherein direct broadcast satellite signals are transmitted from a plurality of satellites in geosynchronous orbit, each satellite separated from each other satellite in a geosynchronous arc by an angle greater than the first directional range of the first antenna and each satellite within a satellite azimuth range within which the first antenna may be positioned to receive signals from any of the satellites, and wherein: the terrestrial azimuth range is separated from the satellite azimuth range by an angle greater than approximately the sum of directional reception range of the first antenna and the directional reception range of the second antenna.

26. The apparatus of Claim 25 further comprising: a plurality of terrestrial transmitters each transmitting from a different terrestrial transmission location and each transmitting in a substantially common azimuth range. P:\OPERK(A'T721537di.c-05i|O/O -16-

27. The apparatus of Claim 24 wherein the first frequency is in a range of 12.2 gigahertz to 12.7 gigahertz.

28. The apparatus of Claim 24 wherein the first frequency is above 12.2 gigahertz.

29. The apparatus of Claim 24 wherein the second antenna is selected from the group consisting of circular wave guide antennas, feed-horn antennas, flat plate antennas, slot antennas, dipole antennas, and multi-dipole antennas. 10

30. The apparatus of Claim 24 wherein the directional reception range of the first antenna is approximately nine degrees. oo

31. A method for simultaneously providing local originating signals on a common frequency with direct broadcast satellite signals transmitted from a satellite, where the satellite is in a first satellite location in geosynchronous orbit about the earth, the method comprising the steps of: at a user location, receiving direct broadcast satellite signals at a first frequency with a first antenna adapted to receive signals at the first frequency only within a first directional reception range as measured from a 20 centerline of the first antenna; transmitting terrestrial signals at the first frequency and in a terrestrial azimuth range from a terrestrial transmitter, the terrestrial azimuth range being outside of the directional reception_ range of the first antenna positioned to receive direct broadcast satellite signals from the satellite; and at the user location, remote from the terrestrial transmitter, receiving the terrestrial signals with a second antenna adapted for receiving signals at the first frequency only within a second directional reception range as measured from a centerline of the second antenna, the second antenna being aligned so that the direct broadcast satellite signals transmitted by the satellite are not transmitted within the directional reception range of the second antenna. P:\OPERWKAT\721537div.doc-5/IOA O -17-

32. The method of Claim 31 further comprising the step of: transmitting terrestrial signals at the first frequency and terrestrial azimuth range from a plurality of terrestrial transmitters.

33. The method of Claim 31 wherein the first frequency is in the range of 12.2 gigahertz to 12.7 gigahertz.

34. The method of Claim 31 wherein the first frequency is above 12.2 gigahertz.

The method of Claim 31 wherein the directional range of the first antenna is approximately nine degrees from the respective antenna centerline.

36. A method for providing simultaneously and on a common frequency direct broadcast signal from a satellite transmitter orbiting the earth and local originating signal from a terrestrial transmitter, in which the direct broadcast and local originating signals are received by respective first and second antennas at the same location, the directivity and orientation of the antennas with respect to the satellite and terrestrial transmitters being such that the first antenna does not receive 20 substantial local originating signal and the second antenna does not receive substantial direct broadcast signal.

37. A method as claimed in claim 36 wherein said satellite transmitter is in geosynchronous orbit.

38. A method as claimed in claim 37 wherein said satellite transmitter is one of a plurality of geosynchronously orbiting satellite transmitters arranged for transmitting respective direct broadcast signals on said common frequency. P:\OPERAT72 37div.doc-05/I OO 18-

39. A method of receiving simultaneously and on a common frequency direct broadcast signal from a satellite transmitter orbiting the earth and local originating signal from a terrestrial transmitter, in which the direct broadcast and local originating signals are received by respective first and second antennas at the same location, the directivity and orientation of the antennas with respect to the satellite and terrestrial transmitters being such that the first antenna does not receive local originating signal and the second antenna does not receive substantial direct broadcast signal. 10

40. A method as claimed in claim 39 wherein said satellite transmitter is in geosynchronous orbit. o. S"41. A method as claimed in claim 40 wherein said satellite transmitter is one of a plurality of geosynchronously orbiting satellite transmitters arranged for transmitting respective direct broadcast signals on said common frequency.

Woo.

42. Apparatus for receiving simultaneously and on a common frequency, at a location, direct broadcast signal from a satellite transmitter orbiting the earth, and local originating signal from a terrestrial transmitter, the apparatus having first and 20 second antennas, at said location, the directivity and orientation of the antennas with respect to the satellite and terrestrial transmitters being such that, when said signals are being simultaneously transmitted, of those signals the first antenna receives substantially only the direct broadcast signal and the second antenna receives substantially only the local originating signal.

43. Apparatus for receiving simultaneously and on a common frequency, at a location, direct broadcast signal from a satellite transmitter geosynchronously orbiting the earth, and local originating signal from a terrestrial transmitter, the apparatus having first and second antennas, at said location, the directivity and orientation of the antennas with respect to the satellite and terrestrial transmitters being such that, y :RKA721537div.doc-05/10/0 -19- when said signals are being simultaneously transmitted, of those signals the first antenna receives substantially only the direct broadcast signal and the second antenna receives substantially only the local originating signal.

44. Apparatus for receiving simultaneously and on a common frequency, at a location, direct broadcast signal from one of a plurality of satellite transmitters geosynchronously orbiting the earth, and local originating signal from a terrestrial transmitter, each of the satellite transmitters being arranged for transmission of a respective said broadcast signal on said common frequency, the apparatus having 10 first and second antennas, at said location, the directivity and orientation of the antennas with respect to the satellite transmitters and the terrestrial transmitter being such that, when the direct broadcast signals from the satellite transmitters and the local originating signals are being simultaneously transmitted, of these signals the first antenna receives substantially only the direct broadcast signal from said 15 one satellite transmitter and the second antenna receives substantially only the local originating signal. DATED this 5 h day of October, 2000 000•0 NORTHPOINT TECHNOLOGY LTD 20 By its Patent Attorneys Davies Collison Cave