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

• US 20010019942A1
• Filed: 02/23/2001
• Published: 09/06/2001
• Est. Priority Date: 10/11/1996
• Status: Active Grant

• Current Assignee: Broadband Investments Limited
• Original Assignee: Northpoint Technology Limited
• Inventors: Tawil, Saleem, Tawil, Carmen
• Granted Patent: US 6,519,446 B2
• Time in Patent Office: Days
• US Class Current: 455/13.1
• CPC Class Codes: H04B 7/18523 Satellite systems for providing broadcast service to terrestrial stations, i.e. broadcast satellite service arrangements specially adapted for satellite broadcast receiving H04H40/90; picture transmission via satellite H04N1/00103; television transmission via satellite H04N7/20
• CPC Class Codes: H04B 7/18563 Arrangements for interconnecting multiple systems data switching networks H04L12/00
• CPC Class Codes: H04H 40/90 specially adapted for satellite broadcast receiving
• CPC Class Codes: H04N 7/20 Adaptations for transmission via a GHz frequency band, e.g. via satellite
• CPC Class Codes: H04W 4/06 Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services
• CPC Class Codes: H04W 84/06 Airborne or Satellite Networks space-based or airborne stations H04B7/185

Abstract

A satellite receiving antenna (16) at a user location (14) receives satellite signals at a first frequency from a satellite (12). The satellite signals travel along a satellite signal route (42) within a look angle about the centerline (28) of the antenna (16). A terrestrial transmitter (20) transmits signals at the first frequency along a wireless transmission route (40) from the transmitter to the user location (14). The terrestrial transmitter (20) is located with respect to the user location (14) so that the wireless transmission route (40) is at a relatively large angle to the centerline (28) of the first antenna (16). The angle of the wireless transmission route (40) to the satellite antenna centerline (28) is large enough so that the terrestrial signals present at the location (14) result in terrestrial input signals from the antenna (16) which are less than an interference level with respect to satellite input signals produced by the antenna. Thus, the terrestrial signals do not interfere with the satellite signals even though they are transmitted at a common frequency.

Claims

1. A method for reusing a first transmission frequency already in use for transmitting satellite signals from a satellite along a satellite signal route to a first location for reception within a satellite signal receiving window of a satellite receiving antenna at the first location, the satellite signals having a signal power level at the first location to produce satellite input signals at least at a minimum useable satellite input signal level when received within the satellite signal receiving window by the satellite receiving antenna, the method comprising the step of:

(a) transmitting terrestrial signals at the first transmission frequency from a first terrestrial transmitter, the terrestrial signals being transmitted in directions including a wireless transmission route from the first terrestrial transmitter to the first location, the wireless transmission route lying at an angle from the satellite signal route such that the terrestrial signals present at the first location produce terrestrial input signals from the satellite receiving antenna aligned to receive the satellite signals within the satellite signal receiving window, the terrestrial input signals being at a power level less than an interference power level with respect to the satellite input signals, and the terrestrial signals present at the first location also having a power level at least at a minimum usable terrestrial signal level.

2. The method of

claim 1

wherein:

(a) the terrestrial signals are transmitted directionally in a limited azimuth range about the first transmitter.

3. The method of

claim 1

wherein the satellite transmits satellite signals along an additional satellite signal route to an additional location for reception within a satellite signal receiving window of a satellite receiving antenna at the additional location, the satellite signals having a signal power level at the additional location to produce satellite input signals at least at the minimum useable satellite input signal level when received within the satellite signal receiving window by the satellite receiving antenna at the additional location, and wherein the method further comprises the step of:

(a) transmitting from the first terrestrial transmitter to the additional location along an additional wireless transmission route, the additional wireless transmission route lying at an angle to the additional satellite signal route such that the terrestrial signals present at the additional location produce additional terrestrial input signals from the satellite receiving antenna aligned to receive the satellite signals at the additional location, the additional terrestrial input signals being at a power level less than an interference power level with respect to the satellite input signals at the additional location, and the terrestrial signals present at the additional location also having a power level at least at the minimum usable terrestrial signal level.

4. The method of

claim 1

wherein the satellite transmits satellite signals along a satellite signal route to a second location for reception within a satellite signal receiving window of a satellite receiving antenna at the second location, the satellite signals having a signal power level at the second location to produce satellite input signals at least at a minimum useable satellite input signal level when received within the satellite signal receiving window by the satellite receiving antenna at the second location, and wherein the method further comprises the step of:

(a) transmitting second terrestrial signals at the first transmission frequency from a second terrestrial transmitter along a second wireless transmission route to the second location, the second terrestrial transmitter having an effective transmission area which is different from an effective transmission area for the first terrestrial transmitter, the second wireless transmission route lying at an angle from the satellite signal route to the second location such that the second terrestrial signals present at the second location produce second terrestrial input signals from the satellite receiving antenna at the second location aligned to receive the satellite signals within the satellite signal receiving window, the second terrestrial input signals being at a power level less than an interference power level with respect to the satellite input signals at the second location, and the second terrestrial signals present at the second location also having a power level at least at the minimum usable terrestrial signal level.

5. The method of

claim 4

wherein:

(a) the first terrestrial transmitter and the second terrestrial transmitter simultaneously transmit the same data at the first transmission frequency.

6. The method of

claim 5

wherein:

(a) the effective transmission area of the first terrestrial transmitter overlaps with the effective transmission area of the second terrestrial transmitter.

7. The method of

claim 4

wherein:

(a) the effective transmission area of the first terrestrial transmitter and the effective transmission area of the second terrestrial transmitter do not overlap; and

(b) the first terrestrial transmitter and the second terrestrial transmitter simultaneously transmit different data at the first transmission frequency.

8. The method of

claim 1

wherein additional satellite signals are transmitted from an additional satellite, the additional satellite transmitting the additional satellite signals along an additional satellite signal route to the first location for reception within a satellite receiving window of an additional satellite receiving antenna at the first location to produce useable satellite input signals at the additional satellite antenna, and wherein:

(a) the wireless transmission route also lies at an angle from the additional satellite signal route such that the terrestrial signals present at the first location produce additional terrestrial input signals from the additional satellite receiving antenna aligned to receive the additional satellite signals within the respective satellite signal receiving window, the additional terrestrial input signals being at a power level less than the interference power level with respect to the satellite input signals at the additional satellite antenna.

9. An apparatus for simultaneously providing terrestrially transmitted signals on a common frequency with satellite signals transmitted from a satellite along a satellite signal route to a first location, the satellite signals being transmitted at a first frequency and having a signal power level at the first location to produce satellite input signals at least at a minimum useable satellite input signal level when received within a satellite signal receiving window by a satellite receiving antenna at the first location, the apparatus comprising:

(a) a first terrestrial transmitter for transmitting terrestrial signals at the first frequency along a wireless transmission route from a first terrestrial transmitter location to the first location, the wireless transmission route lying at an angle from the satellite signal route such that the terrestrial signals present at the first location produce terrestrial input signals from the satellite receiving antenna which are at a power level less than an interference level with respect to the satellite input signals, the terrestrial signals present at the first location also having a power level at least at a minimum usable terrestrial signal level.

10. The apparatus of

claim 9

wherein:

(a) the first terrestrial transmitter comprises a directional transmitter for directionally transmitting the terrestrial signals in a limited azimuth range about the first transmitter.

11. The apparatus of

claim 9

wherein:

(a) the first terrestrial transmitter transmits along a plurality of wireless transmission routes from the first terrestrial transmitter, each wireless transmission route lying at an angle to a satellite signal route from the satellite to a location along the respective wireless transmission route, the angle from the respective satellite signal route being such that the terrestrial signals present at the respective location along the wireless transmission route produce terrestrial input signals from a respective satellite receiving antenna at the respective location which are at a power level less than the interference level with respect to satellite input signals produced from the satellite signals received at the respective satellite receiving antenna at the respective location.

12. The apparatus of

claim 9

further comprising:

(a) a second terrestrial transmitter at a second transmitter location for transmitting terrestrial signals at the first frequency, the second terrestrial transmitter having an effective transmission area which is different from an effective transmission area for the first terrestrial transmitter.

13. The apparatus of

claim 12

further comprising:

(a) signal synchronization means associated with the first terrestrial transmitter and the second terrestrial transmitter, the signal synchronization means enabling the first terrestrial transmitter and the second terrestrial transmitter to simultaneously transmit the same data at the first frequency.

14. The apparatus of

claim 13

wherein:

(a) the effective transmission area of the first terrestrial transmitter overlaps with the effective transmission area of the second terrestrial transmitter.

15. The apparatus of

claim 12

wherein:

(a) the effective transmission area of the first terrestrial transmitter and the effective transmission area of the second terrestrial transmitter do not overlap; and

(b) the first terrestrial transmitter and the second terrestrial transmitter simultaneously transmit different data at the first frequency.

16. An apparatus for simultaneously providing terrestrially transmitted signals on a common frequency with satellite signals transmitted from a satellite, the satellite signals being transmitted at a first frequency along a respective satellite transmission route to each location within a geographic service area for reception within a satellite receiving window of a satellite receiving antenna at the respective location, the satellite signals having a signal power level at the respective location to produce satellite input signals at least at a minimum useable satellite input signal level when received within the satellite signal receiving window of the satellite receiving antenna at the respective location, the apparatus comprising:

(a) a plurality of spaced apart terrestrial transmitters, each terrestrial transmitter adapted for transmitting terrestrial signals at the first frequency, the plurality of spaced apart terrestrial transmitters being arranged such that substantially each respective location within the geographic service area has a wireless transmission route to one of the terrestrial transmitters, the wireless transmission route lying at an angle from the satellite transmission route to the respective location such that the terrestrial signals present at the respective location produce terrestrial input signals when received at the satellite receiving antenna at the respective location aligned to receive the satellite signals within the satellite signal receiving window, the terrestrial input signals being at a power level less than an interference power level with respect to the satellite input signals from the satellite receiving antenna at the respective location, and the terrestrial signals present at the respective location also having a power level at least at a minimum usable terrestrial signal level.

17. The apparatus of

claim 16

wherein:

(a) the plurality of terrestrial transmitters are further arranged such that the terrestrial signals present at any given location in the geographic service area result in an input signal from the respective satellite receiving antenna at the given location which is at or above the interference power level with respect to the satellite input signals at the respective location.

18. The apparatus of

claim 16

further comprising:

(a) signal synchronization means associated with each terrestrial transmitter for enabling the terrestrial transmitters to simultaneously transmit the same signals at the first frequency.

19. The apparatus of

claim 16

wherein:

(a) each terrestrial transmitter transmits across a limited azimuth range from the respective transmitter location.

20. The apparatus of

claim 16

wherein the first frequency is above about 1000 megahertz.

21. A method for reusing a first transmission frequency already in use for transmitting satellite signals from a satellite along a satellite signal route to a first location for reception within a satellite receiving window of a satellite receiving antenna at the first location, the satellite signals having a sufficient signal power level at the first location to result in satellite input signals from the satellite receiving antenna which are at least at a minimum usable satellite input signal level, the method comprising the step of:

(a) transmitting terrestrial signals at the first transmission frequency from a first terrestrial transmitter to the first location, the terrestrial signals present at the first location resulting in terrestrial input signals from the satellite receiving antenna which are at a power level less than an interference power level with respect to the satellite input signals, the terrestrial signals present at the first location also having a power level at least at a minimum usable terrestrial signal level.

22. The method of

claim 21

wherein the satellite transmits satellite signals along a satellite signal route to a second location for reception within a satellite signal receiving window of a satellite receiving antenna at the second location, the satellite signals having a signal power level at the second location to produce satellite input signals at least at a minimum useable satellite input signal level, and wherein the method further comprises the step of:

(a) transmitting second terrestrial signals at the first transmission frequency from a second terrestrial transmitter to the second location, the second terrestrial signals present at the second location resulting in terrestrial input signals from the satellite receiving antenna at the second location which are at a power level less than the interference power level with respect to the satellite input signals at said antenna, the terrestrial signals present at the second location also having a power level at least at a minimum usable terrestrial signal level.

23. The method of

claim 22

further comprising:

(a) simultaneously transmitting the same terrestrial signals at the first frequency from the first and second terrestrial transmitters.

24. The method of

claim 22

wherein:

(a) each terrestrial transmitter transmits across a limited azimuth range from the respective transmitter location.

25. The method of

claim 21

wherein the first frequency is above about 1000 megahertz.

26. 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 along a satellite transmission route to a first location for reception within a satellite signal receiving window of a satellite receiving antenna at the first location, the satellite signals having a signal power level at the first location to produce satellite input signals at least at a minimum useable satellite input signal level when received within the satellite signal receiving window by the satellite receiving antenna, the apparatus comprising:

(a) a terrestrial transmitter for transmitting terrestrial signals at the first frequency from a fixed terrestrial location which forms a fixed geometry with the first location and the satellite, the terrestrial transmitter being located with respect to the first location such that the terrestrial signals present at the first location result in terrestrial input signals from the satellite receiving antenna at the second location which are at a power level less than an interference power level with respect to the satellite input signals at said antenna, the terrestrial signals present at the first location also having a power level at least at a minimum usable terrestrial signal level.

27. The apparatus of

claim 26

wherein:

(a) the terrestrial transmitter transmits along a plurality of wireless transmission routes, each wireless transmission route lying at an angle to a satellite signal route from the satellite to a location along the respective wireless transmission route, the angle from the respective satellite signal route being such that the terrestrial signals present at the respective location along the wireless transmission route produce terrestrial input signals from a respective satellite receiving antenna at the location which are at a power level less than the interference level with respect to satellite input signals produced from the satellite signals received at the respective satellite receiving antenna.