Title of Invention	OPTIMIZED INTEGRATED HIGH CAPACITY DIGITAL SATELLITE TRUNKING NETWORK
Abstract	An optimized integrated high capacity digital satellite trunking network comprising; (a) a satelite comprising power and bandwidth, and having a plurality of transponders; (b) a plurality of earth stations, the plurality of transponders and the plurality of earth stations constituting a communications network; (c) means at each earth terminal for transmitting an uplink signal, on an uplink frequency to one of the plurality of transponders on the satellite; (d) means at each earth terminal for receiving a downlink signal, on a downlink frequency from one of the plurality of transponders; (e) wherein each transponder translates an uplink signal to a downlink signal; and (f) further wherein the uplink signal may be translated to any dpwnlinik&gnal through use of a particular uplink frequency without modication or reconfiguration of the transponder means; and wherein the full bandwidth and power of the satellite is used for the communications network.

Title of Invention

OPTIMIZED INTEGRATED HIGH CAPACITY DIGITAL SATELLITE TRUNKING NETWORK

Abstract

An optimized integrated high capacity digital satellite trunking network comprising; (a) a satelite comprising power and bandwidth, and having a plurality of transponders; (b) a plurality of earth stations, the plurality of transponders and the plurality of earth stations constituting a communications network; (c) means at each earth terminal for transmitting an uplink signal, on an uplink frequency to one of the plurality of transponders on the satellite; (d) means at each earth terminal for receiving a downlink signal, on a downlink frequency from one of the plurality of transponders; (e) wherein each transponder translates an uplink signal to a downlink signal; and (f) further wherein the uplink signal may be translated to any dpwnlinik&gnal through use of a particular uplink frequency without modication or reconfiguration of the transponder means; and wherein the full bandwidth and power of the satellite is used for the communications network.

Full Text	FORM-2 THE PATENTS ACT, 1970 COMPLETE SPECIFICATION SECTION 10 TITLE : OPTIMIZD INTEGRATED HIGH CAPACITY DIGITAL SATELLITE TRUNKING NETWORK. APPLICANTS TRANSWORLD COMMUNICATIONS, (USA) INC. OF 7601 LEWINSVILLE ROAD, SUITE 205, MCLEAN, VA 22102, U.S.A., AN AMERICAN COMPANY. The following Specification particularly describes the nature of this invention and the manner in which it is to be performed :- OPTIMIZED INTEGRATED HIGH CAPACITY DIGITAL SATELLITE TRUNKING NETWORK TECHNICAL FIELD This invention relates generally to the field of satellite communication. More specifically the present invention is an optimized integrated high capacity digital satellite trunking network system, otherwise known as the Multipurpose Wideband Communications System (MPWCS) and method for linking multiple earth stations in the same of different antenna transponder footprints of the same satellite at the greatest officiency in use of power and bandwidth, thereby eliminating the need to reconfigure the satellite transponder based on the desired downlink footprint. BACKGROUND ART Geostationary satellites provide flexible communication relay service using earth stations and satellite transponders, with satellites supporting point to multi-point relay service between earth stations. Satellite operators typically lease transponder capacity based upon power, bandwidth, connectivity, and coverage desired by lessees. The leasing of power, bandwidth, connectivity and coverage of the satellite in a non-optimum manner due to the sharing between different user networks results in less than the maximum satellite power and bandwidth being utilized. Further networks have been historically developed by separate organizations responsible for provision of space segment and earth segment leading to a complex definition of interfaces and less than the highest efficiency in the total capacity which can be derived from the satellite orbit and frequency spectrum which has been assigned. Depending on a number of satellite design parameters (e.g. uplink and downlink frequencies, antenna type, antenna boresight, antenna size, and transmitter powre of the satellite) the effective "earth footprint" of a satellite transponder has geographic limits. The geographic limits of the transponder footprint constrain the type of relay service that may be provided. 2 For two users that are within the same satellite transponder footprint who desire to eastablish a communication link, a usual and simple form of simplex service requires that the transmitting user point their earth terminal antenna at the relay satellite and transmit on an uplink frequency. Using a satellite antenna whose receive footprint includes the earth station location of the transmitting user, the satellite transponder receives the uplink frequency, translates the frequency to a downlink frequency, amplifies the signal and then re-transmits the translated and amplified signal through the same satellite antenna used to receive the signal. The downlink signal can be received by any earth terminal that is within that satellite antenna footprint. Depending on the downlink frequency, and the previously mentioned physical characteristics of the satellite, the downlink footprint may be as small as a few hundred miles in diameter or up to several thousand miles in diameter. For two users who are within the same satellite antenna footprint, this form of relay service is very effective. For two users who are not within the same satellite antenna footprint, but are within the satellite antenna footprint of another antenna on the same satellite, other techniques are used. One technique involves providing an electronic "cross strap" between two antennas/transponders on the same satellite. In this arrangement, the uplink signal from the earth transmitting station is received by one satellite antenna and the signal is translated and amplified for re-transmission by another satellite antenna, whose footprint includes the desired receiver. Using this technique, two uses who are physically distant from each other and are each within small and different satellite antenna footprints of the same satellite may use a single satellite for relay service. Various inventions attempt to address different aspects of these problems. Examples includes United States Patent No. 5,615,407 to Barkats, United States Patent No. 4,720,873 to Goodman et al., United States Patent No. 5,283,639 to Esch et al, United States Patent No. 5,081,703 to Lee, United States Patent No. 5,276,904 to Mutzig et al., United States Patent No. 5,455,823 to Noreen et al., United States Patent No. 5,633,891 to Rebec et al., United States Patent No. 5,424,770 to Schmelzer et al., and United States Patent No. 5,303,393 to Noreen et al. 3 DISCLOSURE OF THE INVENTION It is therefore an object of the present invention to create a satellite network optimized to use the full power and bandwidth of the constituent satellite, thereby providing highest capacity for operation of a digital trunking network based on the integration of the earth stations and satellite for maximum transmission efficiency. It is a further objective of the present invention to create a high capacity satellite communications network where usage is measured by time (minutes-of-use) rather than by power or bandwidth leased by a party. It is yet another objective of the persent invention to create a global digital high capacity telecommunications network using the full power and bandwidth of multiple constituent satellites for any communications services within the field of view of the satellite network. It is a further objective of the present invention to integrate multi-service satellite telecommunications using the full power and bandwidth of constituent satellites for all communications. It is yet another objective of the present invention to provide voice, data, facsimile, video and general bit stream service using the full power and bandwidth of constituent satellites for all communications. It is a further objective of the present invention to provide public switched telephone network services using the full power and bandwidth of constituent satellites for all communications. It is yet another objective of the present invention to provide private branch exchange services to selected groups of users the full power and bandwidth of constituent satellites for all communications. 4 It is a further objective of the present invention to provide overlay network srvices to selected groups of subscribers using the full power and bandwidth of constituent satellites for all communications. It is yet another objective of the present invention to provide domestic and international telecommunications service using the full power and bandwidth of constituent satellites for all communications. It is a further objective of the present invention to link telecommunication services of the present invention with other communications service providers and carriers. It is yet another objective of the present invention to link telecommunication services of the present invention with other terrestrial communications providers and carriers. It is a further objective of the present invention to provide telecommunications services using the full power and bandwidth of constituent satellites for all communications when data being transmitted is either standard or non-standard telecommunications protocols such as but not limited to; ATM, frame relay, internet, XDSL, IP, and/or mobile telecommunications protocols. It is yet another objective of the present invention to provide protocol conversion between different standards of communications between countries and within a single country using multiple protocols. It is therefore an object of the present invention to allow a user»within the satellite antenna footprint of one satellite transponder to flexibly communicate with other users who are within the same or other satellite antenna footprints of a single satellite by using the uplink frequency to selectively select between users and satellite antenna downlink footprints without the need to reconfigure the satellie transponders. 5 It is another object of the present invention to provide the flexible communication capability for wideband high data rate communication. The present invention, otherwise known as MPWCS, generally comprises three spacecraft each of which is in a geosynchronous orbit at three orbital locations. Interacting with the three spacecraft are high-capacity digital earth stations. The digital modulation used is phased shift keying (PSK) and specifically 8-PSK modulation for highest bandwidth efficiency. The use of PSK dramatically increases the channel capacity in bits per Hz which can be carried within a given amount of bandwidth. Relatively large diameter earth station antennas are used to maximise the efficiency with which satellite power is used, for example and without limitation 9 meter antennas are currently used. Further, each earth station has a relatively large high power amplifier to insure communication links are not uplink power limited, for example and without limitation 350 watt amplifiers are currently used. Digital modems are used for all services to be supported by the system of the present invention. Compression technology is also used within the earth segment to take advantage of; silent periods within a voice conversation, statistical utilization of speech activity among multiple voice channels and redundancy within individual voice channels to allow the available satellite communications bandwidth to be allocated to the largest number of voice channels consistent with maintaining high quality and consistent with meeting national and international standards where appropriate. Finally, protocol conversion is implemented throughout the system so that communications using dissimilar protocols can be converted from one to another. This allows communication from regions or countries using dissimilar protocols to occur in a continuous and seamless manner. Taken together these characteristics results in a high capacity satellite based digital trunking network. The present invention overcomes the disadvantages of the prior art through: a) integration of earth and space segments for maximum capacity and efficiency using the available satellite orbit 6 and frequency allocations, and b) providing integrated digital service to users on an end to end basis from switching center toswitching center location. Further, a combination of multiple antennas and transponders on the same satellite, are linked to hybrid signal combiners, wideband receivers, and hybrid signal splitters on the satellite which are able to use a contiguos portion of both the uplink and downlink frequency spectrum. In one embodiment, the present invention uses two transponders with sideband receivers and two 80 MHZ bandwidth portions of the frequency spectrum separated by 64 MHZ to allow a user to flexibly connect an 80 MHZ bandwidth signal between two satellite antenna footprints. In another embodiment of the present invention, a multiplexer is also used to interconnect multiple transponders, allowing a user to select the downlink footprints of more than two transponders based on the uplink frequency. These and other objects of the present invention will be apparent to those of ordinary skill in the art after review of the detailed description, the drawings, and the claims. BRIEF DESCRIPTION OF THE DRAWINGS. Figure 1A shows an overview of the present invention. Figure IB shows satellite locations for satellites of the present invention. Figure 1C shows PSTN backbone service of the present invention. Figure ID shows the present invention providing dedicated services. Figure IE shows regional setup of the present invention. Figure 1 shows a signal flow diagram of the satellite transponder in one embodiment of the present invention. 7 Figure 2 shows an example of the frequency allocation used in one embodiment of the present invention. Figure 3 shows an example of satellite antenna footprints in one embodiment of the present invention. Figure 4 shows an example of the uplink and downlink signals with users in the same satellite antenna footprint. Figure 5 shows an example of the uplink and downlink signals with users in different satellite antenna footprints. Figure 6 shows a signal flow diagram of the satellite transponders in another embodiment of the present invention. Figure 7 shows an example of the frequency allocation used in another embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION Referring to Figure 1A an overview of a single satellite and associated ground stations of the present invention are shown. Satellite 10 is stationed in a geosynchronous orbit thereby allowing the satellite to be stationary relative to a geographic location on the equator of the earth. The satellie communicates with earth station 12 which has a large diameter antenna designed to maximize efficiency of satellite communications. Connected to antenna 12 is a zone toll switch 14 which meters the usage of the satellite link and is the switch through which communications are made to various local public switched telephone networks, overlay networks, and private networks. The various local access switches 16, 18 and 20 are connected to the zone toll switch 14 and provide the access to various individuals and organizations in the local access area. 8 Earth station 12 may, for example and without limitation, communicate with earth station 22 which also comprises a relatively large diameter earth station antenna, again maximizing the effeciency and use by the earth station of satellite power. Earth station 22 is further connected to another zone toll switch 24 also connected generally to another public switched telephone network zone. Once again access of local customers is through a series of local access swtiches 26,28 and 30. Referring to Figure IB the satellite field-of-view areas of the three satellites of the present invention and their orbital locations are shown. In gereral Concept, and without limitation, the present invention requires three satellites for virtually worldwide coverage. The satellites are stationed each in a geosynchonous orbit over ground locations at the equation of 16 degrees West, 77 degrees East, and 167 degrees East Longitude. Referring to Figure 1C the public switched telephone network backbone service is shown. In general concept, and without limitation, four earth stations 32, 34, 36 and 38 are shown. Again each earth station has a relatively large diameter antenna to maximize the efficiency of communications with the satellites of the present invention. Again each earth station has an associated zone toll switch 40, 42, 44 and 46. Further, trunk switches 48, 50, 52 and 54 are directly connected to each earth station antenna and provide the basis for switching and communications being sent and received over that segment of the digital trunking network. The system of the present invention can also interact with the existing terrestrial backbone 56 thereby providing alternative communication means to the existing terrestrial backbone. Communications can thus be carried over the backbone 56 where appropriate or over the high capacity digital satellite trunking network of the present invention. A transit switch 58 is also provided to allow communications with PSTN zones 60 and 62 which may be outside the zone of coverage of the present invention, that is, in regions not covered by the satellite footprint. 9 Referring to Figure ID, other dedicated services which can be serviced by the present invention are shown. Satellite earth stations 64, 66, 68 and 70 interact with the satellite of the present invention to provide the high capacity digital satellite trunking network. Earth station 70 is linked in via its associated trunk switch 72 to various other gateways 74. These gateways provides access to other private communications networks 76. Transit hub 78 provides access to various other local destination 80 via associated transit and terminatin units 82. These other domestic destinations 80 may be outside the satellite footprint or simply not be directly connected to an individual earth station of the present invention. Earth station 68 is connected via its associated trunk switch 84 to a terresstrial fiber-optic or copper transport network 86. Individual private voice 88, a private network 90, or private data access 92 may be connected to this terrestrial network 86. The flexible connection to terrestrial fiber-optic or copper transport networks can be duplicated at any other ground station location. Thus a second terrestrial network 94 may also have private voice 96, private network 98, private data 99, connected to it. Thus the present invention allows data, private networks or any other communications to be connected across broad geographic areas to other terrestrial fiber optic copper or copper transport networks. Referring to Figure IE a typical configuration at any given communication region of the present invention is shown. This is the type of installation that is associated with a ground station in communication with a satellite of the present invention. Earth station 150, with its large diameter antenna is connected to a trunks switch multiplexer 152. This multiplexer allows communications from a variety of different sources to be multiplexed and transmitted over the earth station to maximize utilization of bandwidth. A private network 168 may be directly connected to the trunk switch multiplexer. It should be noted than in this specific example no protocol conversion is needed between the private network or end user and the trunk switch multiplexer. 10 However, the system of the present invention is capable of protocol conversion is situations where communication are coming from other countries, or other regions which simply use different protocols. For example, communication via toll switches 162, 164, and 166 may occur from a given PSTN zone 160. These communications are transmitted through a zone switch 158 to the earth station or over the terrestrial backbone. It the protocol is not the same, protocol converter 154 converts the incoming communication havig a different protocol. Thereafter signals in communications are connected to the trunk switch multiplexer and are transmitted over the high-capacity digital satellite trunking network of the present invention. Each regional earth station also incorporates a redundant call logger 156 which allows the transmission of billing information regarding utilization of the network to the hub station. This billing information is also transmitted at various times, and on a non-interference basis with communication being transmitted over the network. Referring to Figure 1, a signal flow diagram of the satellite transponders in one embodiment is illustrated. Two independently steerable satellite antenna 101, 103 are provided which can be boresighted to provided different earth footprints. The received signal from each satellite antenna is amplified by a low noise amplifier (LNA) 105, 107 prior to signal combination in a hybrid signal combiner 109. The combined signal is then filtered 110 and input to a wideband receiver 111 where the uplink frequency is shifted or translated to the downlink frequency. The translated frequency in then split by a hybrid signal splitter 113 into two signal paths before each is amplifed by a high power amplifier (HPA) 115, 117. Each signal is then filtered 119, 121 and passed to the corresponding satellite antenna 101, 103 for re-transmission on the corresponding downlink frequency. Referring to Figure 2, an example of frequency allocation for one embodiment is illustrated. Two 80 MHZ uplink frequency bands 201, 203 are shown, with a 64 MHZ separation frequency band 205. Two 80 MHZ downlink frequency bands 207, 209 are also shown, with a corresponding 64 MHZ separation frequency band 211. The downlink frequency for antenna 101, in Figure 1, is the lower 80 MHZ band 207 (approximately 12.512 to 12.592 MHZ) while the 11 downlink frequency for antenna 103 is the upper 80 MHZ band 209 (approximately 12.656 to 12.736 MHZ). Referring now to Figure 3, examples of satellite antenna footprints for different transponders are illustrated. The footprint for one antenna (101 in Figure 1) covers one geographic area 301, while the footprint of the other antenna (103 in Figure 1) covers another geographic area 303. Using this embodiment of the present invention, a first user,located within satellite antenna footprint 301, can communicate with a second user also located in satellite antenna footprint 301. Alternatively, a first user, located within satellite antenna footprint 301, can communicate with a third user located in satellite antenna footprint 303. Referring now to Figure 4, examples of the uplink and downlink signals are shown for users who are both in satellite antenna footprint 301 (Figure 3) of satellite antenna 101 (Figure 1). Here, the uplink signal is in the lower of the two 80 MHZ bands 201 (approximately 14.744 to 14.824 MHZ) and the downlink signal is also in the lower of the two 80 MHZ bands 207 (approximately 12.512 to 12.592 MHZ). Referring to Figure 5, examples of the uplink and downlink signals are shown for users who are in different satellite antenna footprints. In this example, the transmitting user is in the satellite antenna footprint 301 (Figure 3) of antenna 101 (Figure 1), while the receiving user is in the satellite antenna footprint 303 (Figure 3) of antenna 103 (Figure 1). Here, the uplink signal is in the upper of the two 80 MHZ band 203 (approximately 14.888 to 14.968 MHZ) and the downlink signal is in the upper of the two 80 MHZ bands 209 (approximately 12.656 to 12.736 MHZ). Referring back to Figures 1 and 2, in this embodiment, both antennas (101, 103 in Figure 1) and LNAS (105, 107 in Figure 1) have sufficient bandwidth to pass both 80 MHZ bands (201, 203 in Figure 2) in addition to a 64 MHZ band separation (205 in Figure 2) into the hybrid signal combiner (109 in Figure 1). This approximately 224 MHZ bandwidth output of the hybrid signal combiner (109 in Figure 1) is processed by a wideband receiver (111 in Figure 1), 12 which performs a frequency translation from the uplink to downlink frequency. The translated frequency output of the wideband receiver is then split into two 80 MHZ downlink signals (207, 209 in Figure 2) before amplification by two HPA's (115, 117 in Figure 1) and transmission through the two antennas (101, 103 in Figure 1). In this example, one transponder downlink antenna (101 in Figure 1) uses the lower frequency band (207 in Figure 2) of the two 80 MHZ bands, and the other transponder downlink antenna (103 in Figure 1) uses the upper frequency band (209 in Figure 2) of the two 80 MHZ bands. Both transponders are thus able to receive both 80 MHZ bands (201,203 in Figure 2). Completing the example, a transmitting user in the satellite antenna footprint of one transponder (301 in Figure 3) who wants to communicate with another receiving user also in the satellite antenna footpint of the same transponder (301 in Figure 3) will uplink in the lower frequency band (201 in Figure 4) of the two 80 MHZ uplink bands. When the uplink frequency is translated to the downlink frequency, the downlink frequency will also be in the lower frequency band (207 is Figures 2 & 4) of the two 80 MHZ downlink bands. Alternatively, a transmitting user in the satellite antenna footpint of the first transponder (301 in Figure 3) who wants to communicate with a second receiving user who is in the satellite antenna footprint of the second transponder (303 in Figure 3) will uplink in the upper frequency band (203 in Figures 2 & 5) of the two 80 MHZ uplink bands. When the uplink frequency is translated to the downlink frequency, the downlink frequency will now be in the upper frequency band (209 in Figures 2 & 5) of the two 80 MHZ downlink bands. This will have the same effect as "cross-strapping" the two transponders would have in the traditional method of operation. Referring now to Figure 6, the signal flow of another embodiment of the present invention is illustrated. This arrangement uses the transponder pair of the first embodiment 600 and adds another transponder pair 602 and further allows users to cross signals between the transponder pairs 604. In this configuration, a multiplexer, IMUX 601, 603 is interposed in the signal path between the antenna 103, 605 and the low noise amplifiers 107, 607. the IMUX provides an alternative signal path that allows signals to be crossed between the transponder pairs 600, 602. After frequency splitting by the IMUX 601, 603, the signal path is similar to the first 13 embodiment. Specifically, the signal is amplified by an LNA 609, 611, followed by a receiver 613, 615 which translate the uplink frequency to the downlink frequency. The frequency translated signals are then amplified by an HPA 617, 619 prior to another multiplex operation OMUX 621,623 and final transmission by the respective antennas 103,605. An example frequency allocation that corresponds to this other embodiment is illustrated in Figure 7. In addition to the technique of the first embodiment, using an orthogonal polarization, the uplink antenna (103 in Figure 6) is able to receive and pass two 80 MHZ bands 701, 703, with a 64 MHZ separation band 705. These two 80MHz bands are received and translated to the downlink frequencies 707, 709 as in the first embodiment. However, the bandwidth that is passed through the uplink antenna (103 in Figure 6) to the IMUX (601, 603 in Figure 6) also includes a 34 MHZ band 711 in addition to a 10 MHZ frequency separation band 713. In this example, this 268 MHZ wideband signal (34+10+80+64+80 MHZ) is divided by th IMUX (601, 603 in Figure 6) into two signal paths. One signal path, the upper 224 MHZ, is handled as in the first embodiment. The other signal path, the lower 34 MHZ 711, is crossed to the other transponder pair (602 in Figure 6). This 14 MHZ signal 711 (14.700 to 14.734 MHZ) is processed by the LNA (611 in Figure 6) and the frequency is translasted to the downlink frequency by a receiver (615 in Figure 6). In the example, the 34 MHZ uplink frequency 711 is translated to the 34 MHZ downlink frequency 715 (11.057 to 11.091 MHZ) before it is amplified by the HPA (617 in Figure 6) and multiplexed with other signals by the OMUX (621 in Figure 6) and finally transmitted through the antenna (605 in Figure 6). The signal flow for transmission from the satellite antenna footpint of satellite antenna 605 to the satellite antenna footprint of satellite antenna 103 is similar to that from satellite antenna 103 to satellite antenna 605. However, the example frequency allocation is different. Referring to Figure 7, the uplink frequency 717 (approximately 15.216 to 15.247 MHZ) and the downlink frequency 719 (approximately 12.769 to 12.803 MHZ) are 34 MHZ wide. For a transmitting user in the satellite antenna footpint of satellite antenna 605 who wants to transmit to a receiving user in the satellite antenna footprint of satellite antenna 625, the uplink 14 frequency will be 721 (approximately 15.130 to 15.180 MHZ) and the downlink frequency will be 723 (approximately 10.977 to 11.027 MHZ). A transmitting user in the satellite antenna footpint of satellite antenna 625 who wants to transmit to a receiving user in the satellite antenna footprint of satellite antenna 605, the uplink frequency will be 725 (approximately 15.271 to 15.321 MHZ) and the downlink frequency 727 (approximately 11.121 to 11.171 MHZ). Referring again to Figure 1, the hardware to accomplish the resent invention must have certain capabilities. The independently steerable satellite antenna 101, 103, must each have sufficient pointing accuracy to track and maintain boresight at sufficient gain to provide the required performance. The low noise amplifier 105, 107 must have a flat response across the dsired spectrum with sufficient gain to provide the required performance. The hyrbrid signal combiner 109 must be capable of receiving two signal sources and suitably combining them into a single composite signal (without adverse noise, attenuation or artifacts) sufficient to provide the required performance. The filter 110 must have suitable cut off and selectivity to provide the required performance. The wideband receiver 111 must be capable of translating the input signal frequency to the desired output signal frequency with sufficient gain to provide the required performance. The hybrid signal splitter 113 must be capable of dividing a single with specified bandwidth into multiple signals of specified bandwidth without adverse attenuation or artifact. The high power amplifiers 115, 117 must be capable of amplificatin across the input frequency spectrum with flat response. Finally, the filters 119, 121 must have suitable cut-off and selectivity to provide the required performance. Referring again to Figure 6, the hardware to accomplish the other embodiment of the present invention must have certain capabilities. The additional independently steerable satellite antenna 625, 605, must each have sufficient pointing accuracy to track and maintain boresight at sufficient gain to provide the required performance. The input multiplexer, IMUX 601, 603 which is interposed in the signal path after the antenna 103, 605 must have sifficient bandwidth to provide the required performance. The low noise amplifier 107, 607, 609 and 611 must have a flat response across the desired spectrum with sufficient gain to provide the required performance. Ther wideband receiver 613, 615 must be capable of translating the input signal 15 frequency to the desired output signal frequency with sufficient gain to provide the required performance. The high power amplifiers 617, 619 must be capable of amplification across the input frequency spectrum with flat response. Finally, the output multiplexer, OMUX 612, 623 must have bandwidth to provide the required performance. An optimized integrated high capacity digital satellite trunking network has been described. Those skilled in the art will appreciate that minor variations may be made to the system described without departing from the scope of the invention as disclosed. 16 WE CLAIM: - 1. An optimized integrated high capacity digital satellite trunking network comprising; (a) a satelite comprising power and bandwidth, and having a plurality of transponders; (b) a plurality of earth stations, the plurality of transponders and the plurality of earth stations constituting a communications network; (c) means at each earth terminal for transmitting an uplink signal, on an uplink frequency to one of the plurality of transponders on the satellite; (d) means at each earth terminal for receiving a downlink signal, on a downlink frequency from one of the plurality of transponders; (e) wherein each transponder translates an uplink signal to a downlink signal; and (f) further wherein the uplink signal may be translated to any dpwnlinik&gnal through use of a particular uplink frequency without modication or reconfiguration of the transponder means; and wherein the full bandwidth and power of the satellite is used for the communications network. 2. The optimized integrated high capacity digital satellite trunking network of claim 1, wherein the uplink and downlink signals and frequencies further comprise: (a) an uplink signal having a first center frequency; (b) a downlink signal having a second center frequency; and (c) wherein the second center frequency is approximately 2.232. GHz less than the first uplink single center frequency. 3. The optimized integrated high capacity digital satellite trunking network of claim 2, wherein the means for translating an uplink signal to a downlink signal further comprises: (a) a signal combiner means on the satellite; 17 (b) a wideband receiver means on the satellite having a receiver bandwidth operating on the output of the signal combiner means; (c) a signal splitter on the satellite operating on the output of the wideband receiver means; (d) wherein more than one of the uplink signals with the second center frequency are combined by the signal combiner means to create a hybrid signal with the second center frequency; (e) further wherein the bandwidth of the wideband receiver means is at least as wide as the receiver bandwidth; and (f) further wherein the signal splitter means converts the output signal of the wideband receiver means having the second center frequency, to more than one downlink signal of the first bandwidth. 4. The optimized integrated high capacity digital satellite trunking network of claim 1, wherein the complete power and bandwidth of the satellite is allocated for the communications network. 5. The optimized integrated high capacity digital satellite trunking network of claim 1, wherein the uplink and downlink signals comprise multi-service telecommunications. 6. The optimized integrated high capacity digital satellite trunking network of claim 5, wherein the multi-service communication is taken from the group consisting of facsimile, voice, data, and video telecommunications. 7. The optimized integrated high capacity digital satellite trunking network of claim 6 wherein the voice telecommunications are public switched telephone network communications. 8. The optimized integrated high capacity digital satellite trunking network of claim 6 wherein the voice communications are private branch exchange telephone communications. 18 9. The optimized integrated high capacity digital satellite trunking network of claim 6 wherein the voice communications are overlay network service communications. 10. The optimized integrated high capacity digital satellite trunking network of claim 1 wherein the uplink and downlink signals are generated and received within a single country. 11. The optimized integrated high capacity digital satellite trunking network of claim 1 wherein the uplink signals are generated in a first country and the downlink signals are received in a second country. 12. The optimized integrated high capacity digital satellite trunking network of claim 11 wherein the network converts the telecommunications protocol from the first country to the telecommunications protocol for the second country. 13. The optimized integrated high capacity digital satellite trunking network of claim 1 wherein the uplink and downlink signals are taken from the group consisting of standard and non-standard telecommunications protocols. 14. A method for providing an optimized integrated high capacity digital satellite trunking network comprising: (a) transmitting an uplink signal from a first of a plurality of earth stations, on an uplink frequency to one of a plurality of transponders on a satellite having power and bandwidth characteristics, the plurality of earth stations and the plurality of satellite transponders constituting a communications network; (b) receiving a downlink signal at a second of a plurality of earth stations, on a downlink frequency from one of the plurality of transponders on the satellite. (c) translating the uplink signal to the downlink signal using at least one of the plurality of satellite transponders; 19 d) wherein the uplink signal may be translated to the downlink signal through use of a particular uplink frequency without modification or reconfiguration of the transponders; and (e) wherein the communications network uses the full power and bandwidth of the satellite. 15. The method for providing an optimized integrated high capacity digital satellite trunking network of claim 14, further comprising: translating the uplink signal having a first center frequency to the downlink signal having a second center frequency wherein the first center frequency is aproximately a positive integer multiple, other than one, of the second center frequency. 16. The method for providing an optimized integrated high capacity digital satellite trunking network of claim 14 wherein translating the uplink signal to the downlink signal further comprises: (a) combining more than one uplink signal with a signal combiner means on the satellite; (b) receiving the output of the signal combiner with a wideband receiver means; (c) splitting the output of the wideband receiver into more than one signal; and (d) wherein the uplink signals have a first center frequency and are combined to create a hybrid signal with the same first center frequency; (e) wherein the bandwidth of the wideband receiver is at least as wide as the first center frequency; and (f) wherein splitting the output of the wideband receiver means creates more than one downlink signal of a second center frequency which is less than the first center frequency. 17. The method for providing an optimized integrated high capacity digital satellite trunking network of claim 14 further comprising utilizing the complete power and bandwidth for the communications network. 20 18. The method for providing an optimized integrated high capacity digital satellite trunking network of claim 14 wherein the uplink and downlink signals comprise multi service telecommunications. 19. The method for providing an optimized integrated high capacity digital satellite trunking network of claim 18 wherein the multi-service telecommunications is taken from the group consisting of facsimile, voice, data, and video. 20. The method for providing an optimized integrated high capacity digital satellite trunking network of claim 19 wherein the voice telecommunications are public switched telephone network telecommunications. 21. The method for providing an optimized integrated high capacity digital satellite trunking network of claim 19 wherein the voice telecommunicaions are private branch exchange telephone communications. 22. The method for providing an optimized integrated high capacity digital satellite trunking network of claim 19 wherein the voice telecommunications are overlay network service communications. 23. The method for providing an optimized integrated high capacity digital satellite trunking network of claim 14 further comprising sending the uplink signals from a first country or a first region within the first country and receiving the downlink signals in the first country or in the first region within the first country. 24. The method for providing an optimized integrated high capacity digital satellite trunking network of claim 14 further comprising sending the upink signals from a first country or a region within the first country and receiving the downlink signals in a second country or a region within the second country. 21 25. The method for providing an optimized integrated high capacity digital satellite trunking network of claim 24 further comprising converting the telecommunications from a first sending protocol to a second receiving protocol. 26. The method for providing an optimized integrated high capacity digital satellite trunking network of claim 14 wherein the uplink and downlink signals are taken from the group consisting of ATM, frame relay internet, XDSL, IP, and mobile communications signals. 27. An optimized integrated high capacity digital satellite trunking network comprising: a first plurality of ground stations optimized to transmit communications in a first bandwidth; at least one communications satellite optimized to receive the communications from the plurality of ground stations in the first bandwidth. at least one communications satellite further transmitting the communications from the first plurality of ground stations in a second bandwidth; a second plurality of ground stations optimized to receive communications from the at least one communications satellite in the second bandwidth, the first plurality of ground stations, the second plurality of ground stations and the at least one communications satellite constituting a communications network; the at least one communications satellite receiving communications in only the first bandwidth and transmitting communications in only the second bandwidth for optimizing power utilization of the at least one communications satellite; and wherein the communication network uses the full power and bandwidth of the at least one communications satellite. 22 28. The optimized integrated high capacity digital satellite trunking network of claim 27 wherein the communications are voice communications. 29. The optimized integrated high capacity digital satellite trunking network of claim 27 wherein the communications are data communications. 30. The optimized integrated high capacity digital satellite trunking network of claim 27 wherein the communications are facsimile communications. 31. The optimized integrated high capacity digital satellite trunking network of claim 27 wherein the communications are video communications. 32. The optimized integrated high capacity digital satellite trunking network of claim 27 wherein the second plurality of ground stations further comprise antenna optimized to receive communications in the second bandwidth from the at least one communications satellite. 33. The optimized integrated high capacity digital satellite trunking network of claim 27 wherein the first plurality of ground stations further comprise antenna optimized to transmit communications in the first bandwidth to the at least one communications satellite. 34. The optimized integrated high capacity digital satellite trunking network of claim 33 wherein the first plurality of ground stations is part of a digital terrestrial communications network. 35. The optimized integrated high capacity digital satellite trunking network of claim 33 wherein the second plurality of ground stations is part of a digital terrestrial communications network. 23 36. The optimized integrated high capacity digital satellite trunking network of claim 27 wherein the at least one communications satellite comprises three communications satellites in geostationary orbit. 37. The optimized integrated high capacity digital satellite trunking network of claim 36 wherein a first satellite is located at about 16 degrees West. Longitude, a second satellite is located at about 77 degrees East. Longitude, and a third satellite is located at about 167 degrees East Longitude. 38. The optimized integrated high capacity digital satellite trunking network of claim 13 wherein the standard telecommunications protocols are taken from the group consisting of ATM, frame relay, Internet XDSL, BP, and mobile communicationsvproblems; Dated this 23rd day of October, 2000. HIRAL CHANDRAKANT JOSHI AGENT FOR TRANSWORLD COMMUNICATIONS, INC. 24

Full Text

FORM-2
THE PATENTS ACT, 1970
COMPLETE SPECIFICATION
SECTION 10
TITLE : OPTIMIZD INTEGRATED HIGH CAPACITY DIGITAL SATELLITE TRUNKING NETWORK.

APPLICANTS

TRANSWORLD COMMUNICATIONS, (USA) INC. OF 7601 LEWINSVILLE ROAD, SUITE 205, MCLEAN, VA 22102, U.S.A., AN AMERICAN COMPANY.

The following Specification particularly describes the nature of this invention and the manner
in which it is to be performed :-

OPTIMIZED INTEGRATED HIGH CAPACITY DIGITAL SATELLITE TRUNKING NETWORK
TECHNICAL FIELD
This invention relates generally to the field of satellite communication. More specifically the present invention is an optimized integrated high capacity digital satellite trunking network system, otherwise known as the Multipurpose Wideband Communications System (MPWCS) and method for linking multiple earth stations in the same of different antenna transponder footprints of the same satellite at the greatest officiency in use of power and bandwidth, thereby eliminating the need to reconfigure the satellite transponder based on the desired downlink footprint.
BACKGROUND ART
Geostationary satellites provide flexible communication relay service using earth stations and satellite transponders, with satellites supporting point to multi-point relay service between earth stations. Satellite operators typically lease transponder capacity based upon power, bandwidth, connectivity, and coverage desired by lessees. The leasing of power, bandwidth, connectivity and coverage of the satellite in a non-optimum manner due to the sharing between different user networks results in less than the maximum satellite power and bandwidth being utilized. Further networks have been historically developed by separate organizations responsible for provision of space segment and earth segment leading to a complex definition of interfaces and less than the highest efficiency in the total capacity which can be derived from the satellite orbit and frequency spectrum which has been assigned. Depending on a number of satellite design parameters (e.g. uplink and downlink frequencies, antenna type, antenna boresight, antenna size, and transmitter powre of the satellite) the effective "earth footprint" of a satellite transponder has geographic limits. The geographic limits of the transponder footprint constrain the type of relay service that may be provided.
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For two users that are within the same satellite transponder footprint who desire to eastablish a communication link, a usual and simple form of simplex service requires that the transmitting user point their earth terminal antenna at the relay satellite and transmit on an uplink frequency. Using a satellite antenna whose receive footprint includes the earth station location of the transmitting user, the satellite transponder receives the uplink frequency, translates the frequency to a downlink frequency, amplifies the signal and then re-transmits the translated and amplified signal through the same satellite antenna used to receive the signal. The downlink signal can be received by any earth terminal that is within that satellite antenna footprint. Depending on the downlink frequency, and the previously mentioned physical characteristics of the satellite, the downlink footprint may be as small as a few hundred miles in diameter or up to several thousand miles in diameter. For two users who are within the same satellite antenna footprint, this form of relay service is very effective.
For two users who are not within the same satellite antenna footprint, but are within the satellite antenna footprint of another antenna on the same satellite, other techniques are used. One technique involves providing an electronic "cross strap" between two antennas/transponders on the same satellite. In this arrangement, the uplink signal from the earth transmitting station is received by one satellite antenna and the signal is translated and amplified for re-transmission by another satellite antenna, whose footprint includes the desired receiver. Using this technique, two uses who are physically distant from each other and are each within small and different satellite antenna footprints of the same satellite may use a single satellite for relay service.
Various inventions attempt to address different aspects of these problems. Examples includes United States Patent No. 5,615,407 to Barkats, United States Patent No. 4,720,873 to Goodman et al., United States Patent No. 5,283,639 to Esch et al, United States Patent No. 5,081,703 to Lee, United States Patent No. 5,276,904 to Mutzig et al., United States Patent No. 5,455,823 to Noreen et al., United States Patent No. 5,633,891 to Rebec et al., United States Patent No. 5,424,770 to Schmelzer et al., and United States Patent No. 5,303,393 to Noreen et al.
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DISCLOSURE OF THE INVENTION
It is therefore an object of the present invention to create a satellite network optimized to use the full power and bandwidth of the constituent satellite, thereby providing highest capacity for operation of a digital trunking network based on the integration of the earth stations and satellite for maximum transmission efficiency.
It is a further objective of the present invention to create a high capacity satellite communications network where usage is measured by time (minutes-of-use) rather than by power or bandwidth leased by a party.
It is yet another objective of the persent invention to create a global digital high capacity telecommunications network using the full power and bandwidth of multiple constituent satellites for any communications services within the field of view of the satellite network.
It is a further objective of the present invention to integrate multi-service satellite telecommunications using the full power and bandwidth of constituent satellites for all communications.
It is yet another objective of the present invention to provide voice, data, facsimile, video and general bit stream service using the full power and bandwidth of constituent satellites for all communications.
It is a further objective of the present invention to provide public switched telephone network services using the full power and bandwidth of constituent satellites for all communications.
It is yet another objective of the present invention to provide private branch exchange services to selected groups of users the full power and bandwidth of constituent satellites for all communications.
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It is a further objective of the present invention to provide overlay network srvices to selected groups of subscribers using the full power and bandwidth of constituent satellites for all communications.
It is yet another objective of the present invention to provide domestic and international telecommunications service using the full power and bandwidth of constituent satellites for all communications.
It is a further objective of the present invention to link telecommunication services of the present invention with other communications service providers and carriers.
It is yet another objective of the present invention to link telecommunication services of the present invention with other terrestrial communications providers and carriers.
It is a further objective of the present invention to provide telecommunications services using the full power and bandwidth of constituent satellites for all communications when data being transmitted is either standard or non-standard telecommunications protocols such as but not limited to; ATM, frame relay, internet, XDSL, IP, and/or mobile telecommunications protocols.
It is yet another objective of the present invention to provide protocol conversion between different standards of communications between countries and within a single country using multiple protocols.
It is therefore an object of the present invention to allow a user»within the satellite antenna footprint of one satellite transponder to flexibly communicate with other users who are within the same or other satellite antenna footprints of a single satellite by using the uplink frequency to selectively select between users and satellite antenna downlink footprints without the need to reconfigure the satellie transponders.
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It is another object of the present invention to provide the flexible communication capability for wideband high data rate communication.
The present invention, otherwise known as MPWCS, generally comprises three spacecraft each of which is in a geosynchronous orbit at three orbital locations. Interacting with the three spacecraft are high-capacity digital earth stations. The digital modulation used is phased shift keying (PSK) and specifically 8-PSK modulation for highest bandwidth efficiency. The use of PSK dramatically increases the channel capacity in bits per Hz which can be carried within a given amount of bandwidth.
Relatively large diameter earth station antennas are used to maximise the efficiency with which satellite power is used, for example and without limitation 9 meter antennas are currently used. Further, each earth station has a relatively large high power amplifier to insure communication links are not uplink power limited, for example and without limitation 350 watt amplifiers are currently used. Digital modems are used for all services to be supported by the system of the present invention. Compression technology is also used within the earth segment to take advantage of; silent periods within a voice conversation, statistical utilization of speech activity among multiple voice channels and redundancy within individual voice channels to allow the available satellite communications bandwidth to be allocated to the largest number of voice channels consistent with maintaining high quality and consistent with meeting national and international standards where appropriate.
Finally, protocol conversion is implemented throughout the system so that communications using dissimilar protocols can be converted from one to another. This allows communication from regions or countries using dissimilar protocols to occur in a continuous and seamless manner. Taken together these characteristics results in a high capacity satellite based digital trunking network.
The present invention overcomes the disadvantages of the prior art through: a) integration of earth and space segments for maximum capacity and efficiency using the available satellite orbit
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and frequency allocations, and b) providing integrated digital service to users on an end to end basis from switching center toswitching center location. Further, a combination of multiple antennas and transponders on the same satellite, are linked to hybrid signal combiners, wideband receivers, and hybrid signal splitters on the satellite which are able to use a contiguos portion of both the uplink and downlink frequency spectrum. In one embodiment, the present invention uses two transponders with sideband receivers and two 80 MHZ bandwidth portions of the frequency spectrum separated by 64 MHZ to allow a user to flexibly connect an 80 MHZ bandwidth signal between two satellite antenna footprints.
In another embodiment of the present invention, a multiplexer is also used to interconnect multiple transponders, allowing a user to select the downlink footprints of more than two transponders based on the uplink frequency.
These and other objects of the present invention will be apparent to those of ordinary skill in the art after review of the detailed description, the drawings, and the claims.
BRIEF DESCRIPTION OF THE DRAWINGS.
Figure 1A shows an overview of the present invention.
Figure IB shows satellite locations for satellites of the present invention.
Figure 1C shows PSTN backbone service of the present invention.
Figure ID shows the present invention providing dedicated services.
Figure IE shows regional setup of the present invention.
Figure 1 shows a signal flow diagram of the satellite transponder in one embodiment of the present invention.
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Figure 2 shows an example of the frequency allocation used in one embodiment of the present invention.
Figure 3 shows an example of satellite antenna footprints in one embodiment of the present invention.
Figure 4 shows an example of the uplink and downlink signals with users in the same satellite antenna footprint.
Figure 5 shows an example of the uplink and downlink signals with users in different satellite antenna footprints.
Figure 6 shows a signal flow diagram of the satellite transponders in another embodiment of the present invention.
Figure 7 shows an example of the frequency allocation used in another embodiment of the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
Referring to Figure 1A an overview of a single satellite and associated ground stations of the present invention are shown. Satellite 10 is stationed in a geosynchronous orbit thereby allowing the satellite to be stationary relative to a geographic location on the equator of the earth. The satellie communicates with earth station 12 which has a large diameter antenna designed to maximize efficiency of satellite communications. Connected to antenna 12 is a zone toll switch 14 which meters the usage of the satellite link and is the switch through which communications are made to various local public switched telephone networks, overlay networks, and private networks. The various local access switches 16, 18 and 20 are connected to the zone toll switch 14 and provide the access to various individuals and organizations in the local access area.
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Earth station 12 may, for example and without limitation, communicate with earth station 22 which also comprises a relatively large diameter earth station antenna, again maximizing the effeciency and use by the earth station of satellite power. Earth station 22 is further connected to another zone toll switch 24 also connected generally to another public switched telephone network zone. Once again access of local customers is through a series of local access swtiches 26,28 and 30.
Referring to Figure IB the satellite field-of-view areas of the three satellites of the present invention and their orbital locations are shown. In gereral Concept, and without limitation, the present invention requires three satellites for virtually worldwide coverage. The satellites are stationed each in a geosynchonous orbit over ground locations at the equation of 16 degrees West, 77 degrees East, and 167 degrees East Longitude.
Referring to Figure 1C the public switched telephone network backbone service is shown. In general concept, and without limitation, four earth stations 32, 34, 36 and 38 are shown. Again each earth station has a relatively large diameter antenna to maximize the efficiency of communications with the satellites of the present invention. Again each earth station has an associated zone toll switch 40, 42, 44 and 46. Further, trunk switches 48, 50, 52 and 54 are directly connected to each earth station antenna and provide the basis for switching and communications being sent and received over that segment of the digital trunking network.
The system of the present invention can also interact with the existing terrestrial backbone 56 thereby providing alternative communication means to the existing terrestrial backbone. Communications can thus be carried over the backbone 56 where appropriate or over the high capacity digital satellite trunking network of the present invention. A transit switch 58 is also provided to allow communications with PSTN zones 60 and 62 which may be outside the zone of coverage of the present invention, that is, in regions not covered by the satellite footprint.
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Referring to Figure ID, other dedicated services which can be serviced by the present invention are shown. Satellite earth stations 64, 66, 68 and 70 interact with the satellite of the present invention to provide the high capacity digital satellite trunking network. Earth station 70 is linked in via its associated trunk switch 72 to various other gateways 74. These gateways provides access to other private communications networks 76. Transit hub 78 provides access to various other local destination 80 via associated transit and terminatin units 82. These other domestic destinations 80 may be outside the satellite footprint or simply not be directly connected to an individual earth station of the present invention.
Earth station 68 is connected via its associated trunk switch 84 to a terresstrial fiber-optic or copper transport network 86. Individual private voice 88, a private network 90, or private data access 92 may be connected to this terrestrial network 86.
The flexible connection to terrestrial fiber-optic or copper transport networks can be duplicated at any other ground station location. Thus a second terrestrial network 94 may also have private voice 96, private network 98, private data 99, connected to it. Thus the present invention allows data, private networks or any other communications to be connected across broad geographic areas to other terrestrial fiber optic copper or copper transport networks.
Referring to Figure IE a typical configuration at any given communication region of the present invention is shown. This is the type of installation that is associated with a ground station in communication with a satellite of the present invention. Earth station 150, with its large diameter antenna is connected to a trunks switch multiplexer 152. This multiplexer allows communications from a variety of different sources to be multiplexed and transmitted over the earth station to maximize utilization of bandwidth. A private network 168 may be directly connected to the trunk switch multiplexer. It should be noted than in this specific example no protocol conversion is needed between the private network or end user and the trunk switch multiplexer.
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However, the system of the present invention is capable of protocol conversion is situations where communication are coming from other countries, or other regions which simply use different protocols. For example, communication via toll switches 162, 164, and 166 may occur from a given PSTN zone 160. These communications are transmitted through a zone switch 158 to the earth station or over the terrestrial backbone. It the protocol is not the same, protocol converter 154 converts the incoming communication havig a different protocol. Thereafter signals in communications are connected to the trunk switch multiplexer and are transmitted over the high-capacity digital satellite trunking network of the present invention.
Each regional earth station also incorporates a redundant call logger 156 which allows the transmission of billing information regarding utilization of the network to the hub station. This billing information is also transmitted at various times, and on a non-interference basis with communication being transmitted over the network.
Referring to Figure 1, a signal flow diagram of the satellite transponders in one embodiment is illustrated. Two independently steerable satellite antenna 101, 103 are provided which can be boresighted to provided different earth footprints. The received signal from each satellite antenna is amplified by a low noise amplifier (LNA) 105, 107 prior to signal combination in a hybrid signal combiner 109. The combined signal is then filtered 110 and input to a wideband receiver 111 where the uplink frequency is shifted or translated to the downlink frequency. The translated frequency in then split by a hybrid signal splitter 113 into two signal paths before each is amplifed by a high power amplifier (HPA) 115, 117. Each signal is then filtered 119, 121 and passed to the corresponding satellite antenna 101, 103 for re-transmission on the corresponding downlink frequency.
Referring to Figure 2, an example of frequency allocation for one embodiment is illustrated. Two 80 MHZ uplink frequency bands 201, 203 are shown, with a 64 MHZ separation frequency band 205. Two 80 MHZ downlink frequency bands 207, 209 are also shown, with a corresponding 64 MHZ separation frequency band 211. The downlink frequency for antenna 101, in Figure 1, is the lower 80 MHZ band 207 (approximately 12.512 to 12.592 MHZ) while the
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downlink frequency for antenna 103 is the upper 80 MHZ band 209 (approximately 12.656 to 12.736 MHZ).
Referring now to Figure 3, examples of satellite antenna footprints for different transponders are illustrated. The footprint for one antenna (101 in Figure 1) covers one geographic area 301, while the footprint of the other antenna (103 in Figure 1) covers another geographic area 303. Using this embodiment of the present invention, a first user,located within satellite antenna footprint 301, can communicate with a second user also located in satellite antenna footprint 301. Alternatively, a first user, located within satellite antenna footprint 301, can communicate with a third user located in satellite antenna footprint 303.
Referring now to Figure 4, examples of the uplink and downlink signals are shown for users who are both in satellite antenna footprint 301 (Figure 3) of satellite antenna 101 (Figure 1). Here, the uplink signal is in the lower of the two 80 MHZ bands 201 (approximately 14.744 to 14.824 MHZ) and the downlink signal is also in the lower of the two 80 MHZ bands 207 (approximately 12.512 to 12.592 MHZ).
Referring to Figure 5, examples of the uplink and downlink signals are shown for users who are in different satellite antenna footprints. In this example, the transmitting user is in the satellite antenna footprint 301 (Figure 3) of antenna 101 (Figure 1), while the receiving user is in the satellite antenna footprint 303 (Figure 3) of antenna 103 (Figure 1). Here, the uplink signal is in the upper of the two 80 MHZ band 203 (approximately 14.888 to 14.968 MHZ) and the downlink signal is in the upper of the two 80 MHZ bands 209 (approximately 12.656 to 12.736 MHZ).
Referring back to Figures 1 and 2, in this embodiment, both antennas (101, 103 in Figure 1) and LNAS (105, 107 in Figure 1) have sufficient bandwidth to pass both 80 MHZ bands (201, 203 in Figure 2) in addition to a 64 MHZ band separation (205 in Figure 2) into the hybrid signal combiner (109 in Figure 1). This approximately 224 MHZ bandwidth output of the hybrid signal combiner (109 in Figure 1) is processed by a wideband receiver (111 in Figure 1),
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which performs a frequency translation from the uplink to downlink frequency. The translated frequency output of the wideband receiver is then split into two 80 MHZ downlink signals (207, 209 in Figure 2) before amplification by two HPA's (115, 117 in Figure 1) and transmission through the two antennas (101, 103 in Figure 1). In this example, one transponder downlink antenna (101 in Figure 1) uses the lower frequency band (207 in Figure 2) of the two 80 MHZ bands, and the other transponder downlink antenna (103 in Figure 1) uses the upper frequency band (209 in Figure 2) of the two 80 MHZ bands. Both transponders are thus able to receive both 80 MHZ bands (201,203 in Figure 2).
Completing the example, a transmitting user in the satellite antenna footprint of one transponder (301 in Figure 3) who wants to communicate with another receiving user also in the satellite antenna footpint of the same transponder (301 in Figure 3) will uplink in the lower frequency band (201 in Figure 4) of the two 80 MHZ uplink bands. When the uplink frequency is translated to the downlink frequency, the downlink frequency will also be in the lower frequency band (207 is Figures 2 & 4) of the two 80 MHZ downlink bands. Alternatively, a transmitting user in the satellite antenna footpint of the first transponder (301 in Figure 3) who wants to communicate with a second receiving user who is in the satellite antenna footprint of the second transponder (303 in Figure 3) will uplink in the upper frequency band (203 in Figures 2 & 5) of the two 80 MHZ uplink bands. When the uplink frequency is translated to the downlink frequency, the downlink frequency will now be in the upper frequency band (209 in Figures 2 & 5) of the two 80 MHZ downlink bands. This will have the same effect as "cross-strapping" the two transponders would have in the traditional method of operation.
Referring now to Figure 6, the signal flow of another embodiment of the present invention is illustrated. This arrangement uses the transponder pair of the first embodiment 600 and adds another transponder pair 602 and further allows users to cross signals between the transponder pairs 604. In this configuration, a multiplexer, IMUX 601, 603 is interposed in the signal path between the antenna 103, 605 and the low noise amplifiers 107, 607. the IMUX provides an alternative signal path that allows signals to be crossed between the transponder pairs 600, 602. After frequency splitting by the IMUX 601, 603, the signal path is similar to the first
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embodiment. Specifically, the signal is amplified by an LNA 609, 611, followed by a receiver 613, 615 which translate the uplink frequency to the downlink frequency. The frequency translated signals are then amplified by an HPA 617, 619 prior to another multiplex operation OMUX 621,623 and final transmission by the respective antennas 103,605.
An example frequency allocation that corresponds to this other embodiment is illustrated in Figure 7. In addition to the technique of the first embodiment, using an orthogonal polarization, the uplink antenna (103 in Figure 6) is able to receive and pass two 80 MHZ bands 701, 703, with a 64 MHZ separation band 705. These two 80MHz bands are received and translated to the downlink frequencies 707, 709 as in the first embodiment. However, the bandwidth that is passed through the uplink antenna (103 in Figure 6) to the IMUX (601, 603 in Figure 6) also includes a 34 MHZ band 711 in addition to a 10 MHZ frequency separation band 713. In this example, this 268 MHZ wideband signal (34+10+80+64+80 MHZ) is divided by th IMUX (601, 603 in Figure 6) into two signal paths. One signal path, the upper 224 MHZ, is handled as in the first embodiment. The other signal path, the lower 34 MHZ 711, is crossed to the other transponder pair (602 in Figure 6). This 14 MHZ signal 711 (14.700 to 14.734 MHZ) is processed by the LNA (611 in Figure 6) and the frequency is translasted to the downlink frequency by a receiver (615 in Figure 6). In the example, the 34 MHZ uplink frequency 711 is translated to the 34 MHZ downlink frequency 715 (11.057 to 11.091 MHZ) before it is amplified by the HPA (617 in Figure 6) and multiplexed with other signals by the OMUX (621 in Figure 6) and finally transmitted through the antenna (605 in Figure 6).
The signal flow for transmission from the satellite antenna footpint of satellite antenna 605 to the satellite antenna footprint of satellite antenna 103 is similar to that from satellite antenna 103 to satellite antenna 605. However, the example frequency allocation is different. Referring to Figure 7, the uplink frequency 717 (approximately 15.216 to 15.247 MHZ) and the downlink frequency 719 (approximately 12.769 to 12.803 MHZ) are 34 MHZ wide.
For a transmitting user in the satellite antenna footpint of satellite antenna 605 who wants to transmit to a receiving user in the satellite antenna footprint of satellite antenna 625, the uplink
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frequency will be 721 (approximately 15.130 to 15.180 MHZ) and the downlink frequency will be 723 (approximately 10.977 to 11.027 MHZ). A transmitting user in the satellite antenna footpint of satellite antenna 625 who wants to transmit to a receiving user in the satellite antenna footprint of satellite antenna 605, the uplink frequency will be 725 (approximately 15.271 to 15.321 MHZ) and the downlink frequency 727 (approximately 11.121 to 11.171 MHZ).
Referring again to Figure 1, the hardware to accomplish the resent invention must have certain capabilities. The independently steerable satellite antenna 101, 103, must each have sufficient pointing accuracy to track and maintain boresight at sufficient gain to provide the required performance. The low noise amplifier 105, 107 must have a flat response across the dsired spectrum with sufficient gain to provide the required performance. The hyrbrid signal combiner 109 must be capable of receiving two signal sources and suitably combining them into a single composite signal (without adverse noise, attenuation or artifacts) sufficient to provide the required performance. The filter 110 must have suitable cut off and selectivity to provide the required performance. The wideband receiver 111 must be capable of translating the input signal frequency to the desired output signal frequency with sufficient gain to provide the required performance. The hybrid signal splitter 113 must be capable of dividing a single with specified bandwidth into multiple signals of specified bandwidth without adverse attenuation or artifact. The high power amplifiers 115, 117 must be capable of amplificatin across the input frequency spectrum with flat response. Finally, the filters 119, 121 must have suitable cut-off and selectivity to provide the required performance.
Referring again to Figure 6, the hardware to accomplish the other embodiment of the present invention must have certain capabilities. The additional independently steerable satellite antenna 625, 605, must each have sufficient pointing accuracy to track and maintain boresight at sufficient gain to provide the required performance. The input multiplexer, IMUX 601, 603 which is interposed in the signal path after the antenna 103, 605 must have sifficient bandwidth to provide the required performance. The low noise amplifier 107, 607, 609 and 611 must have a flat response across the desired spectrum with sufficient gain to provide the required performance. Ther wideband receiver 613, 615 must be capable of translating the input signal
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frequency to the desired output signal frequency with sufficient gain to provide the required performance. The high power amplifiers 617, 619 must be capable of amplification across the input frequency spectrum with flat response. Finally, the output multiplexer, OMUX 612, 623 must have bandwidth to provide the required performance.
An optimized integrated high capacity digital satellite trunking network has been described. Those skilled in the art will appreciate that minor variations may be made to the system described without departing from the scope of the invention as disclosed.
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WE CLAIM: -
1. An optimized integrated high capacity digital satellite trunking network comprising;
(a) a satelite comprising power and bandwidth, and having a plurality of transponders;
(b) a plurality of earth stations, the plurality of transponders and the plurality of earth stations constituting a communications network;
(c) means at each earth terminal for transmitting an uplink signal, on an uplink frequency to one of the plurality of transponders on the satellite;
(d) means at each earth terminal for receiving a downlink signal, on a downlink frequency from one of the plurality of transponders;
(e) wherein each transponder translates an uplink signal to a downlink signal; and
(f) further wherein the uplink signal may be translated to any dpwnlinik&gnal through use of a particular uplink frequency without modication or reconfiguration of the transponder means; and wherein the full bandwidth and power of the satellite is used for the communications network.
2. The optimized integrated high capacity digital satellite trunking network of claim 1,
wherein the uplink and downlink signals and frequencies further comprise:
(a) an uplink signal having a first center frequency;
(b) a downlink signal having a second center frequency; and
(c) wherein the second center frequency is approximately 2.232. GHz less than the first uplink single center frequency.
3. The optimized integrated high capacity digital satellite trunking network of claim 2,
wherein the means for translating an uplink signal to a downlink signal further
comprises:
(a) a signal combiner means on the satellite;
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(b) a wideband receiver means on the satellite having a receiver bandwidth operating on the
output of the signal combiner means;
(c) a signal splitter on the satellite operating on the output of the wideband receiver means;
(d) wherein more than one of the uplink signals with the second center frequency are combined by the signal combiner means to create a hybrid signal with the second center frequency;
(e) further wherein the bandwidth of the wideband receiver means is at least as wide as the receiver bandwidth; and
(f) further wherein the signal splitter means converts the output signal of the wideband receiver means having the second center frequency, to more than one downlink signal of the first bandwidth.

4. The optimized integrated high capacity digital satellite trunking network of claim 1, wherein the complete power and bandwidth of the satellite is allocated for the communications network.
5. The optimized integrated high capacity digital satellite trunking network of claim 1, wherein the uplink and downlink signals comprise multi-service telecommunications.
6. The optimized integrated high capacity digital satellite trunking network of claim 5, wherein the multi-service communication is taken from the group consisting of facsimile, voice, data, and video telecommunications.
7. The optimized integrated high capacity digital satellite trunking network of claim 6 wherein the voice telecommunications are public switched telephone network communications.
8. The optimized integrated high capacity digital satellite trunking network of claim 6 wherein the voice communications are private branch exchange telephone communications.
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9. The optimized integrated high capacity digital satellite trunking network of claim 6 wherein the voice communications are overlay network service communications.
10. The optimized integrated high capacity digital satellite trunking network of claim 1 wherein the uplink and downlink signals are generated and received within a single country.
11. The optimized integrated high capacity digital satellite trunking network of claim 1 wherein the uplink signals are generated in a first country and the downlink signals are received in a second country.
12. The optimized integrated high capacity digital satellite trunking network of claim 11 wherein the network converts the telecommunications protocol from the first country to the telecommunications protocol for the second country.
13. The optimized integrated high capacity digital satellite trunking network of claim 1 wherein the uplink and downlink signals are taken from the group consisting of standard and non-standard telecommunications protocols.
14. A method for providing an optimized integrated high capacity digital satellite trunking network comprising:
(a) transmitting an uplink signal from a first of a plurality of earth stations, on an uplink
frequency to one of a plurality of transponders on a satellite having power and bandwidth
characteristics, the plurality of earth stations and the plurality of satellite transponders
constituting a communications network;
(b) receiving a downlink signal at a second of a plurality of earth stations, on a downlink frequency from one of the plurality of transponders on the satellite.
(c) translating the uplink signal to the downlink signal using at least one of the plurality of satellite transponders;
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d) wherein the uplink signal may be translated to the downlink signal through use of a particular uplink frequency without modification or reconfiguration of the transponders; and
(e) wherein the communications network uses the full power and bandwidth of the satellite.
15. The method for providing an optimized integrated high capacity digital satellite trunking
network of claim 14, further comprising:
translating the uplink signal having a first center frequency to the downlink signal having a second center frequency wherein the first center frequency is aproximately a positive integer multiple, other than one, of the second center frequency.
16. The method for providing an optimized integrated high capacity digital satellite trunking
network of claim 14 wherein translating the uplink signal to the downlink signal further
comprises:
(a) combining more than one uplink signal with a signal combiner means on the satellite;
(b) receiving the output of the signal combiner with a wideband receiver means;
(c) splitting the output of the wideband receiver into more than one signal; and
(d) wherein the uplink signals have a first center frequency and are combined to create a hybrid signal with the same first center frequency;
(e) wherein the bandwidth of the wideband receiver is at least as wide as the first center frequency; and
(f) wherein splitting the output of the wideband receiver means creates more than one downlink signal of a second center frequency which is less than the first center frequency.
17. The method for providing an optimized integrated high capacity digital satellite trunking
network of claim 14 further comprising utilizing the complete power and bandwidth for
the communications network.
20

18. The method for providing an optimized integrated high capacity digital satellite trunking network of claim 14 wherein the uplink and downlink signals comprise multi service telecommunications.
19. The method for providing an optimized integrated high capacity digital satellite trunking network of claim 18 wherein the multi-service telecommunications is taken from the group consisting of facsimile, voice, data, and video.
20. The method for providing an optimized integrated high capacity digital satellite trunking network of claim 19 wherein the voice telecommunications are public switched telephone network telecommunications.
21. The method for providing an optimized integrated high capacity digital satellite trunking network of claim 19 wherein the voice telecommunicaions are private branch exchange telephone communications.
22. The method for providing an optimized integrated high capacity digital satellite trunking network of claim 19 wherein the voice telecommunications are overlay network service communications.
23. The method for providing an optimized integrated high capacity digital satellite trunking network of claim 14 further comprising sending the uplink signals from a first country or a first region within the first country and receiving the downlink signals in the first country or in the first region within the first country.
24. The method for providing an optimized integrated high capacity digital satellite trunking network of claim 14 further comprising sending the upink signals from a first country or a region within the first country and receiving the downlink signals in a second country or a region within the second country.
21

25. The method for providing an optimized integrated high capacity digital satellite trunking network of claim 24 further comprising converting the telecommunications from a first sending protocol to a second receiving protocol.
26. The method for providing an optimized integrated high capacity digital satellite trunking network of claim 14 wherein the uplink and downlink signals are taken from the group consisting of ATM, frame relay internet, XDSL, IP, and mobile communications signals.
27. An optimized integrated high capacity digital satellite trunking network comprising:
a first plurality of ground stations optimized to transmit communications in a first bandwidth;
at least one communications satellite optimized to receive the communications from the plurality of ground stations in the first bandwidth.
at least one communications satellite further transmitting the communications from the first plurality of ground stations in a second bandwidth;
a second plurality of ground stations optimized to receive communications from the at least one communications satellite in the second bandwidth, the first plurality of ground stations, the second plurality of ground stations and the at least one communications satellite constituting a communications network;
the at least one communications satellite receiving communications in only the first bandwidth and transmitting communications in only the second bandwidth for optimizing power utilization of the at least one communications satellite; and
wherein the communication network uses the full power and bandwidth of the at least one communications satellite.
22

28. The optimized integrated high capacity digital satellite trunking network of claim 27 wherein the communications are voice communications.
29. The optimized integrated high capacity digital satellite trunking network of claim 27 wherein the communications are data communications.
30. The optimized integrated high capacity digital satellite trunking network of claim 27 wherein the communications are facsimile communications.
31. The optimized integrated high capacity digital satellite trunking network of claim 27 wherein the communications are video communications.
32. The optimized integrated high capacity digital satellite trunking network of claim 27 wherein the second plurality of ground stations further comprise antenna optimized to receive communications in the second bandwidth from the at least one communications satellite.
33. The optimized integrated high capacity digital satellite trunking network of claim 27 wherein the first plurality of ground stations further comprise antenna optimized to transmit communications in the first bandwidth to the at least one communications satellite.
34. The optimized integrated high capacity digital satellite trunking network of claim 33 wherein the first plurality of ground stations is part of a digital terrestrial communications network.
35. The optimized integrated high capacity digital satellite trunking network of claim 33 wherein the second plurality of ground stations is part of a digital terrestrial communications network.
23

36. The optimized integrated high capacity digital satellite trunking network of claim 27 wherein the at least one communications satellite comprises three communications satellites in geostationary orbit.
37. The optimized integrated high capacity digital satellite trunking network of claim 36 wherein a first satellite is located at about 16 degrees West. Longitude, a second satellite is located at about 77 degrees East. Longitude, and a third satellite is located at about 167 degrees East Longitude.
38. The optimized integrated high capacity digital satellite trunking network of claim 13 wherein the standard telecommunications protocols are taken from the group consisting of ATM, frame relay, Internet XDSL, BP, and mobile communicationsvproblems;
Dated this 23rd day of October, 2000.

HIRAL CHANDRAKANT JOSHI AGENT FOR TRANSWORLD COMMUNICATIONS, INC.
24

Documents:

abstract1.jpg

in-pct-2000-00531-mum-cancelled pages(3-3-2004).pdf

in-pct-2000-00531-mum-claims(granted)-(3-3-2004).doc

in-pct-2000-00531-mum-claims(granted)-(3-3-2004).pdf

in-pct-2000-00531-mum-correspondence(12-3-2004).pdf

in-pct-2000-00531-mum-correspondence(ipo)-(25-8-2004).pdf

in-pct-2000-00531-mum-drawing(3-3-2004).pdf

in-pct-2000-00531-mum-form 1a(16-1-2003).pdf

in-pct-2000-00531-mum-form 1a(3-3-2004).pdf

in-pct-2000-00531-mum-form 2(granted)-(3-3-2004).doc

in-pct-2000-00531-mum-form 2(granted)-(3-3-2004).pdf

in-pct-2000-00531-mum-form 26(18-3-2001).pdf

in-pct-2000-00531-mum-form 6(17-7-2001).pdf

in-pct-2000-00531-mum-form-pct-ipea-409(23-10-2000).pdf

in-pct-2000-00531-mum-form-pct-isa-210(23-10-2000).pdf

in-pct-2000-00531-mum-other documents(13-12-2002).pdf

in-pct-2000-00531-mum-other documents(23-10-2000).pdf

in-pct-2000-00531-mum-power of attorney(18-3-2001).pdf

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Patent Number

206068

Indian Patent Application Number

IN/PCT/2000/00531/MUM

PG Journal Number

28/2007

Publication Date

13-Jul-2007

Grant Date

17-Apr-2007

Date of Filing

23-Oct-2000

Name of Patentee

TRANSWORLD COMMUNICATIONS, (USA) INC.

Applicant Address

7601 LEWINSVILLE ROAD, SUITE 205, MCLEAN, VA 22102, U.S.A.

Inventors:

#	Inventor's Name	Inventor's Address
1	MILLMAN, RICHARD, M.	973 SPENCERT ROAD, MCLEAN, VA 22102, U.S.A.

PCT International Classification Number

H04J 1/00

PCT International Application Number

PCT/US99/08803

PCT International Filing date

1999-04-22

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	09 / 064,900	1998-04-23	U.S.A.