OA11329A - System for selectively downloading information at user terminals from the internet using a satellitebroadcast system - Google Patents

Abstract

A satellite direct digital broadcast system is provided which broadcasts selected Internet information such as news reports, weather reports and stock market rates, along with radio programs. Broadcast channels comprise Internet information and a service control header to identify the type of Internet information contained therein. User terminals (22) are provided which comprise a radio broadcast receiver (2) to receive programs broadcast via satellite (20). Audio programs are played on a speaker connected to a radio broadcast receiver (21). The user terminals (22) also comprise a multimedia device such as a personal computer (29) connected to the receiver. The multimedia device is programmed to generate a computer display which prompts a user to select a topic of Internet information. The multimedia device stores received packets and selectively retrieves packets to generate displays such as Web pages using those packets which correspond to the topic of information selected by the user.

Description

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5 SYSTEM FOR SELECTIVELY DOWNLOADING INFORMATION AT USER TERMINALS FROM THE INTERNETUSING A SATELLITE BROADCAST SYSTEM 10

Field of the Invention

The présent invention relates generally to a System for providing remote userterminais with broadcast Internet information without requiring a backhaul link from theterminais to Internet service providers. 15

Background of the Invention

Due to the expanding, worldwide use of personal computing devices,télécommunications devices and the Internet, the global economy is currently undergoing aninformation révolution that is expected to be as significant as the industrial révolution of the 20 nineteenth century. A significantly large population of people, however, are generallyundeserved and dissatisfied with their télécommunications options and are thereforepresently limited in their ability to participate in this information révolution. Thispopulation of people is primarily located in Africa, Central America, South America andAsia, where communication services hâve, to date, been characterized by the poor Sound 25 quality of short-wave radio brôadcasts, or the coverage limitations of amplitude modulation(AM) band and frequency modulation (FM) band terrestrial radio broadcast Systems. A satellite-based direct radio broadcast System to transmit audio and data signais,including images, to low-cost consumer receivers in essentially any part of the world has beenproposed. The satellite-based direct radio broadcast System provides a number of advantages 3 0 over existing satellite Systems, such as the ability to provide portable services. Many existing satellite Systems fail to provide portable services because they require large satellite antennas to access such Systems. While a number of other existing satellite Systems can provide portable or mobile communication services, these Systems do not provide adéquate channel capacity to provide the high outbound data rates required for transmission of information from the Internet and the World Wide Web (WWW) to many different users. A satellite-based. direct radio broadeast system, however, is limited in that the 5 receivers are one-way and do not permit users to transmit voice or other information. Usersof these receivers, therefore, cannot communicate bi-directionally via the satellite-based directradio broadeast System and, accordingly, do not hâve access to the Internet. In manyconventional Internet access Systems, a user connects with an Internet access provider usine acomputer and a communication link such as a public switched téléphoné network. A senes 10 of screens are generated on the monitor of the user’s computer which prompt the user toselect the kind of information the user seeks to obtain from the Internet. For example, theuser may elect to use Netscape Navigator™ software available from NetscapeCommunications Corporation™ of Mountain View, California to access documents on theWorld Wide Web portion of the Internet. The Netscape Navigator™ software allows the 15. user to enter key words relating to selected topics which are transmitted to a Web searchengine, for example, to obtain information on the selected topics. Existing radio broadeastreceivers are not configured with a communication link between the users and the Internetaccess providers with which to interactively select and download information from theInternet. 20 A substantial amount of information on the Internet, however, is relevant to such a large population as to make the provision of the same information to different users, atdifferent times, on different communication channels, and in response to individual userrequests, an inefficient use of bandwidth and other satellite communication system resources.Thus, a need exists for a low-cost user terminal which provides users with the advantages of 25 a satellite-based direct radio broadeast system (e.g., large géographie coverage, good soundquality, high outbound data rates and low cost), as well as the ability to receive selectedbroadeast information from the Internet.

Summarv of the Invention 3 0 In view of the foregoing disadvantages and limitations, it is an object of the présent invention to provide a satellite direct digital broadeast system which can broadeast selected

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Internet information to low-cost user terminais. The selected Internet information can be,for example, weather reports, news reports, stock market rates, consumer catalogs, amongother types of information. A further object of the présent invention is to broadcast selected types of Internet5 information as packets in broadcast channels. Internet packets are streamed over broadcastchannels of the satellite direct digital broadcast System. A broadcast channel can carry one ormore types of Internet information such as news, weather, stock reports, and so on. Also,the Internet packets contain the information necessary to select spécifie pages (e.g., categories of Internet information) by means of a browser. 10 A further object of the présent invention is to provide low-cost user terminal comprising a radio broadcast receiver which is adapted for connection to a multimedia devicesuch as a personal computer.

It is still a further object of the invention to provide the user terminal with a userinterface for selecting the type of broadcast Internet information to be stored for display 15 purposes at the user terminal. The user terminal uses the sélection entered via a user interfaceto examine stored packets and retrieve those packets corresponding to the Internetinformation-type sélection by the user. The packets are displayed (or played, if audio) using amultimedia device.

These and other objects of the présent invention are achieved, in part, by providing 2 0 remote users with user terminais which incorporate both a broadcast receiver for receivingsatellite direct radio broadeasts, and a multimedia device for storing and displaying selectedinformation from an Internet service provider which has been broadcast via a satellite directradio broadcast System. The user terminais are programmed to convert user informationsélections indicating the type of Internet information desired by the user into control signais 25 for commanding the multimedia device to extract those received packets corresponding tothe user information sélections for display or playback purposes.

In one aspect, therefore, an Internet service provider has a gateway configured toroute selected multimedia data from the Intemet/WWW to a broadcast station. Thebroadcast station formats the Internet packet data into a broadcast program comprising the 30 packets and transmits the broadcast program to a satellite in the satellite direct digitalbroadcast System. The service provider supplies additional information to identify those 4 01Iô29 packets which correspond to the different types of Internet information (e.g., news, consumer catalogs, educational program, and so on) in the broadcast programs.

In another aspect, the présent invention is directed to a method for providing a low- cost, global, portable user terminal with at least limited access to information services 5 available via the Internet. The method comprises the steps of generating screen prompts on amultimedia device (e.g., a personal computer) connected to a radio broadcast receiver. Thescreen prompts allow a user to select from among different types of Internet informationwhich are broadcast via a satellite direct digital broadcast System. The receiver démultiplexesand décodés data received from the satellite direct radio broadcast System to obtain the 10 broadcast channels. User responses to screen prompts are processed by the computer toconfigure the computer to extract selected packets in the broadcast channels which constitutea broadcast program comprising Internet information. The multimedia device first storespackets from the broadcast channel in a large memory device such as a disk drive for laceraccess by the user. 15

Brief Description of the Drawings

The various objects, advantages and novel features of the présent invention will bemore readily comprehended from the following detailed description when read inconjunction with the appended drawings, in which: 2 0 Fig. 1 is a diagrammatic illustration of the manner in which Internet information can be broadcast to users through a satellite direct radio broadcast System in accordance with apreferred embodiment of the présent invention;

Fig. 2 is a schematic block diagram illustrating the operation of a broadcast stationdepicted in Fig. 1 in accordance with an embodiment of the présent invention; 25 Fig. 3 is a diagrammatic illustration of the manner in which broadcast channels are formatted by a broadcast station into prime rate channels for transmission to the satellitedepicted in Fig. 1 in accordance with an embodiment of the présent invention;

Fig. 4 illustrâtes the manner in which on-board satellite signal processing may becarried out in a satellite direct radio broadcast System of the type shown in Fig. 1; 30 Fig. 5 is a schematic block diagram of on-board processing components of the satellite depicted in Fig. 1;

Fig. 6 is a block diagram illustrating the construction of a user terminal which incorporâtes both a digital broadcast receiver and a multimedia device such as a personal computer in accordance with a preferred embodiment of the présent invention;

Fig. 7 is a flow chart which summarizes the sériés of operations carried out by the 5 user terminal of Fig. 5 when downloading selected packets of received broadcast Internet information in accordance with an embodiment of the présent invention; and

Fig. 8 is an exemplary computer screen generated by the user terminal in accordancewith an embodiment of the présent invention.

Throughout the drawing figures, like reference numerals will be understood to refer10 to like parts and components.

Detailed Description of the Preferred Embodiments

The satellite communications System 10 of the présent invention is described below in15 accordance with the following general outline: I. OverView of System Operation H. Broadcast Station HL Satellite IV. User Terminais 20 I. OverView of Svstem Operation

With reference to Fig. 1, a System 10 is provided which allows a remotely located userto receive high quality sound, data and images using a low-cost receiver, and to select one ormore broadcast channels comprising Internet information to download to a computer 25 connected to the receiver in accordance with the présent invention. The System 10 ispreferably implemented using a satellite direct digital broadcast System. The direct digitalbroadcast System preferably consists of three geostationary satellites (one of which isindicated at 20 in Fig. 1), low cost radio receivers or user terminais, and associated groundnetworks. For illustrative purposes, a single user terminal 22 is shown. which comprises a 3 0 hand-held radio receiver 21 connected to a multimedia device such as a computer 29. 0ΐΊΰ29

Broadcast programs are transmitted to the satellite 20 via one or more broadcaststations 26. As will be described in further detail below, the broadcast stations 26 performcoding, multiplexing and other signal processing on programs comprising audio, data or bothto create broadcast channels (BCS) that are transmitted to the satellite 20 in uplinks 28. The 5 uplinks 28 are preferably frequency division multiplexed carriers which carry BCS in termsof prime rate channels (PRCs). Each PRC provides a prime rate incrément (PRI) of 16 kbpsat baseband. A BC preferably comprises 1 to 8 PRCs. For each PRC, the BC is assigned 224bits every 432 milliseconds in a service control header (SCH). The BCS carry packets, someof which constitute programs originating from the Internet. In accordance with the présent 10 invention, the type of Internet information is identified in the SCH. The satellite 20performs baseband processing on the uplinks 28 to transmit the PRCs of the BC to the userterminais 22 on at least one of three time division multiplexed downlinks 30.

With continued reference to Fig. 1, the broadcast stations 26 can be provided withmultimedia information (e.g., Sound bytes, video and Web pages) from the Internet 25 15 directly via a System gateway 23 and a hub 27. The System gateway 23 can operate as anInternet service provider, as well as perform operations which are common to two or moreInternet service providers indicated generally at 31 and combined at the hub 27.

In accordance with an aspect of the présent invention, news répons, weather répons,stock market rates, educational programs, consumer catalogs and other information that is 20 accessible via the Internet are provided to the broadcast stations 26 in the System 10. Thesvstem 10 détermines which type of Internet information is to be broadcast and at whichtimes. The System 10 comprises a régional broadcast control facility (RBCF) 39 which can beused to assign channels on the uplinks 28 to different broadcast stations 26. For example,channels in the uplinks 28 can be assigned to one or more broadcast stations 26 to broadcast 25 news continuously for 24 hours a day. One of the broadcast stations 26 can be controlled toprovide stock market data during the operating times for that particular market. At ail othertimes, the broadcast station can be configured to broadcast stock market news commentaryand régional news at altemate one-half hour intervals. Further, a broadcast station can beconfigured to broadcast weather répons continuously on one broadcast channel, as well as to 30 simultaneously broadcast educational programs and consumer catalogs at specified timesduring the day on another broadcast channel. A schedule of broadcast programs and their corresponding broadcast times and channels is distributed among the users. The users can therefore décidé when and to what TDM downlink 30 to tune the receiver to receive a particular program, including programs comprising Internet information.

In addition, browser pages for different consumer broadcast packages can be 5 assembled at a central location (e.g., a service provider 31a) and provided at one or morebroadcast stations 26. The browser pages for a consumer broadcast package can provide thecurrent news highlights and stock quotes for the présent day, while another consumerbroadcast page provides a browser page dedicated to sports highlights. The program materialcan be obtained from the Internet, providing the basis for placing Internet addresses in 10 packets for their sélective downloading and display on a multimedia device connected to areceiver.

In accordance with the présent invention, each user terminal 22 is configured toreceive satellite direct radio broadcast programs via a radio receiver 21. As stated previously,the receiver 21 can be tuned to receive broadcast programs from a selected one of the three 15 downlinks 30. The receiver 21 is configured to demultiplex and décodé the selecteddownlink 30 to obtain broadcast channels that were transmitted from the broadcast stations26 and provided to the downlink 30 by the satellite 20. The computer 29 connected to thereceiver 22 processes the demultiplexed and decoded and stored data to extract packetscorresponding to a selected category or type of Internet information requested by a user. 20 The computer 29 stores and then annunciates the information, that is, displays theinformation on a computer monitor or plays audio portions of the selected Internetinformation on a loudspeaker connected to the computer.

Using the multimedia device, the user can request to view, listen to or store aparticular type of information which has been demultiplexed, decoded and stored from 25 broadcast channels 100 (Fig. 3). An input device (e.g., a mouse or a keyboard) can be used torespond to screen prompts generated by the computer 29. The screen prompts are preferablyone or more screens having menus for listing different information types (e.g., news,weather, educational programs, consumer products, stock market répons, and so on) andcorresponding icons. The user can dick on an icon using a mouse, for example. The 3 0 computer 29 processes the mouse input to détermine which menu item has been selected and Ο ; ’ί Û 2 ✓ to configure the computer 29 to annunciate stored Internet information corresponding to theuser’s sélection, as described in further detail below in connection with Figs. 7 and 8.

The System 10 is advantageous because it can download relatively large amounts ofinformation from one or more Internet service providers, for example, to a user terminal 22 5 efficiently and cost effectively using the satellite direct radio broadcast System. Differenttypes of information such as news and weather répons are desired by such a great number ofpeople that broadcasting the information to ail user terminais 22 for sélective réception ismore cost effective than providing the data to the space segment each time it is requested by auser. In addition to conserving the space segment, broadcasting popular Internet information 10 and providing user terminais with means to select from among the broadcast Internetinformation does not require modification of the broadcast System to include a backhaul linkwith which to communicate user requests and responses to an Internet service provider inorder to obtain Internet information. 15 H, Broadcast Station

The direct radio broadcast System uses digital audio coding techniques. Each satellite20 delivers direct radio audio signais having qualities équivalent to AM monaural, FMmonaural, FM stéréo and CD stéréo throughout its respective coverage area, together with 20 ancillary data such as paging, video and texx transmissions directly to the user terminais 22.The System can also deliver multimedia services such as large database downloads to personalcomputers (PCs) for business applications, map and printed text information for travelers,and color images to augment audio programs for advertising and entertainment.

Signal processing to convert digital data streams from one or more broadcast station 25 26 into parallel streams for transmission to a satellite 20 will now be described with reference to Fig. 2. For illustrative purposes, four sources 60, 64, 68 and 72 of program information areshown. Two sources 60 and 64, or 68 and 72, are coded and transmitted together as part of asingle broadcast program or service. The coding of the program comprising combinedsources 60 and 64 will be described. The signal processing of the program comprising 3 0 information from sources 68 and 72 is identical. Ο ί 1 S 2 2

Broadcast stations 26 assemble information from one or more sources 60 and 64 for aparticular program into broadcast channels which are preferably c’naracterized by incrémentsof 16 kbps. These incréments are referred to as prime rate incréments or PRIs. Thus, the bitrate carried in a broadcast channel 100, as shown in Fig. 3, is n x 16 kbps were n is the 5 number of PRIs used by that particular broadcast service provider. In addition, each 16 kbpsPRI can be further divided into two 8 kbps segments 101 and 103 (Fig. 3) which are routed orswitched together through the System 10. The segments 101 and 103 provide a mechanismfor carrying two different service items in the same PRI such as a data stream with low bitrate speech signais, or two low bit rate speech channels for two respective languages, and so 10 on. The number of PRIs are preferably predetermined, that is, set in accordance withprogram code. The number n, however, is not a physical limitation of the System 10. Thevalue of n is generally set on the basis of business concems such as the cost of a singlebroadcast channel and the willingness of the service providers to pay.

For illustrative purposes, n for the first broadcast channel 59 for sources 60 and 64 is 15 equal to 4. The value of n for the broadcast channel 67 for sources 68 and 72 is set to 6 in theillustrated embodiment. As stated previously, the value of n can be changed. For example, agreater number of PRIs can be required if one of the sources 60, 64, 68 or 72 is a source forInternet information to be broadcast, particularlv if the information comprises a videocomponent. 20 With continued reference to Fig. 2, more than one broadcast service provider can hâve access to a single broadcast station 26. For example, a first service provider generatesbroadcast channel 59, while a second service provider can generate broadcast channel 67. Thesignal processing described herein and in accordance with the présent invention allows digitaldata streams from several broadcast service providers to be broadcast to a satellite in parallel 2 5 streams which reduces the cost of broadcasting for the service providers and maximizes use of the space segment. By maximizing efficiency of space segment usage, the broadcast stations26 can be implemented less expensively using less power-consuming components. Forexample, the antenna at the broadcast station 26 can be very small aperture terminal (VSAT)antenna. The payload on the satellite requires less memory, less processing capability and 3 0 therefore fewer power sources which reduces payload weight. 10 0 i ’i û2c>

A broadcast channel 59 or 67 is characterized by a frame 100 having a period durationof 432 ms, as shown in Fig. 3. This period duration is selected to facilitate use of the MPEGsource coder described below; however, the frame period in the System 10 can be set to adifferent predetermined value. If the period duration is 432 ms, then each 16 kbps PRI 5 requires 16,000 x 0.432 seconds = 6912 bits per frame. As shown in Fig. 3, a broadcastchannel therefore consists of a value n of these 16 kbps PRIs which are carried as a group inthe frame 100. As will be described below, these bits are scrambled to enhance démodulationat the radio receivers 29. The scrambling operation also provides a mechanism forencrypting the service at the option of the service provider. Each frame 100 is assigned n x 10 224 bits which correspond to a service control header (SCH) 102, resulting in a total of n x 7136 bits per frame and a bit rate of n x (16,518 -i-14/27) bits per second. The purpose of theSCH 102 is to send data to each of the radio receivers 29 tuned to receive the broadcastchannel 59 or 67 in order to control réception modes for various multimedia services, todisplay data and images, to send key information for decryption, to address a spécifie 15 receiver, among other features. The service control header 102 can be provided withinformation necessary to select Internet information, and to decrypt pay-per-use-type ofInternet information.

The sources 60 and 64 are coded using, for example, MPEG 2.5 Laver 3 coders 62 and66, respectively, as shown in Fig. 2. The two sources are subsequently added via a combiner 20 76 and then processed using a processor at the broadcast station 26 to provide the coded signais in periodic frames of 432 ms, that is, n x 7136 bits per frame including the SCH, asindicated by processing module 78 in Fig. 2. In addition, information-type identification datacan be provided in the SCH of the BC.

The blocks indicated at the broadcast station 26 in Fig. 2 correspond to programmed 25 modules performed by a processor and associated hardware such as digital memory and codercircuits. The bits in the frame 100 are subsequently coded for FEC protection using digitalsignal processing (DSP) software, application spécifie integrated circuits (ASICs) and customlarge-scale intégration (LSI) chips for the two concatenated coding methods. First, a ReedSolomon coder 80a is provided to produce 255 bits for every 223 bits entering the coder. The 30 bits in the frame 100 are then reordered according to a known interleaving scheme, asindicated by reference numéral 80b. The interleaving coding provides further protection 011329 against bursts of error encountered in a transmission sincs this method spreads damaged bitsover several channels. With continued reference to processing module 80, a knownconvolution coding scheme of constraint length 7 is applied using a Viterbi coder 80c. TheViterbi coder 83c produces two output bits for every input bit, producing as a net resuit 5 16320 FEC-coded bits per frame for each incrément of 6912 bits per frame applied in the broadcast channel 59. Thus, each FEC-coded broadcast channel (e.g., channel 59 or 67)comprises n x 16320 bits of information which hâve been coded, reordered and coded againsuch that the original broadcast 16 kbps PRIs are no longer identifiable. The FEC-coded bits,however, are organized in terms of the original 432 ms frame structure. The overall coding 10 rate for error protection is (255/223) x 2 = 2 + 64/223.

With continued reference to Fig. 2, the n x 16320 bits of the FEC-coded broadcast channel frame is subsequently subdivided or demultiplexed using a channel distributor 82into n parallel prime rate channels (PRCs), each carrying 16320 bits in terms of sets of 8160two-bit symbols. This process is further illustrated in Fig. 3. The broadcast channel 59 is 15 shown which is characterized by a 432 ms frame 100 having an SCH 102. The remainingportion 104 of the frame consists of n 16 kbps PRIs which corresponds to 6912 bits per framefor each of the n PRIs. The FEC-coded broadcast channel 106 is attained followingconcatenated Reed Solomon 255/223, interleaving and FEC 1/2 convolution codingdescribed above in connection with module 80. 20 As stated previously, the FEC-coded broadcast channel frame 106 comprises n x 16320 bits which correspond to 8160 sets of two-bit symbols, with each Symbol beingdesignated by a reference numéral 108 for illustrated purposes. In accordance with theprésent invention, the symbols are assigned across the PRCs 110 in the manner shown in Fig.3. Thus, the symbols are spread on the basis of time and frequency which further reduces 25 errors at the radio receiver 21 that are caused by interférence in transmission. The serviceprovider for broadcast channel 59 has purchased four PRCs for illustrative purposes, whereasthe service provider for broadcast channel 67 has purchased six PRCs for illustrativepurposes. Fig. 3 illustrâtes the first broadcast channel 59 and the assignment of symbols 114across the n = 4 PRCs 110a, 110b, 110c and llOd, respectively. To implement recovery of 3 0 each two-bit svmbol 114 set at the receiver, a PRC synchronization header or preamble 112a, 112b, 112c and 112d, respectively, is placed in front of each PRC. The PRC synchronization 12 header (hereinafter generally referred to using reference numéral 112) contains 48 symbols.

The PRC synchronization header 112 is placed in front of each group of 8160 symbols, thereby increasing the number of symbols per 432 ms frame to 8208 symbols. Accordingly, the symbol rate becomes 8208/0.432 which equals 19,000 kilosymbols per second (ksym/s) 5 for each PRC 110. The 48 symbol PRC preamble 112 is used essentially for synchronizationof the radio receiver PRC clock to recover the symbols from the downlink satellitetransmission 27. At the on-board processor 116, the PRC preamble is used to absorb timingdifférences between the symbol rates of arriving uplink signais and that used on-board toswitch the signais and assemble the downlink TDM streams. This is done by adding a "0" to 10 or subtracting a "0" from each 48 symbol PRC, or abstaining from both operations, in therate alignment process used on-board the satellite 20. Thus, the PRC preambles carried onthe TDM downlink has 47, 48 or 49 symbols as determined by the rate alignment process.As shown in Fig. 3, symbols 114 are assigned to consecutive PRCs in a round-robin fashionsuch that symbol 1 is assigned to PRC 110a, symbol 2 is assigned to PRC 110b, symbol 3 is 15 assigned to PRC 110c, symbol 4 is assigned to PRC llOd, symbol 5 is assigned to PRC 110a,and so on. This PRC demultiplexing process is performed by a processor at the broadcaststation 26 and is represented in Fig. 2 as the channel distribution (DEMUX) module 82.

The PRC channel preambles are assigned to mark the beginning of the PRC frames110a, 110b, 110c and llOd for broadcast channel 59 using the preamble module 84 and adder 20 module 85. The n PRCs are subsequently differentially encoded and then QPSK modulatedonto an IF carrier frequency using a bank of QPSK modulators 86 as shown in Fig. 2. Fourof the QPSK modulators 86a, 86b, 86c and 86d are used for respective PRCs 110a, 110b, 110cand llOd for broadcast channel 59. Accordingly, there are four PRC IF carrier frequenciesconstituting the broadcast channel 59. Each of the four carrier frequencies is up-converted to 25 its assigned frequency location in the X-band using an up-converter 88 for transmission to thesatellite 20. The up-converted PRCs are subsequently transmitted through an amplifier 90 tothe antenna (e.g., a VSAT) 92a and 92b.

The SCH 102 inserted into each coded PRC preferably comprises a control word toidentify the program channel to which the PRC belongs and to carry instructions that allow 3 0 the receiver to recombine the coded prime rate channels to reconstruct the coded programchannels. An exemplary eighty (80) bit control word is: 0 o2 5 10 15 20 25 30 35 40 13 # Bits Indication 2 Quantity Of Related Ensembles (00 = no relation, four related ensemblesmaximum) 2 Ensemble Identification Number (00=Ensemble #1, ll=Ensemble 4) 4 Ensemble Type (0000=Audio, 0001 =Video, C010=Data, othertypes or reserved) 3 Quantity Of 16 kbps Prime Rate ChannelsIn Ensemble (000=1 channel, 001=2 channels,..., 111 = 8 channels) 3 Prime Rate Channel Identification Number (000=channel 1,..., lll=channel 8) 3 Quantity Of Sub-Ensembles (000=1,..., 111 = 8) 3 Quantity Of 16 kbps Prime Rate Channels

In Sub-Ensemble(000=1,..., 111=8) 2 Sub-Ensemble Identification Number(000=Ensemble #1,..., lll=Ensemble 8) 3 Ensemble/Sub-Ensemble Blocking(000=no blocking, 001=type 1 blocking, ···» 111=type 7 blocking) 11 Reserved 40 CRC.

The control word entry for the Quantity of Related Ensembles allows a relationshipto be created between various groups of ensembles. For example, a broadcaster mav wish toprovide related audio, video and data services, such as electronic newspaper with audio text,and additional information. The Ensemble Identification Number identifies the ensemblenumber of winch the channel is a part. The Quantity Of 16 kbps Prime Rate Channels InEnsemble defines the number of prime rate channels in the ensemble. The Quantity Of Sub-Ensembles and Quantity of 16 kbps Prime Rate Channels In Sub-Ensemble defines arelationship within an ensemble, such as, in a CD quality stéréo ensemble, use of four primerate channels for a “Left Stéréo” signal and four different prime rate channels for a “RightStéréo” signal. Altematively, music may be associated with multiple voice signais forannouncers, each voice signal in a different language. The Quantity Of 16 kbps Prime Rate

Channels In Sub-Ensemble defines the number of prime rate channels in the sub-ensemble.The Sub-Ensemble Identification Number identifies the sub-ensemble of which the channel isa part.

The Ensemble/Sub-Ensemble Blocking bits allow cooperative blocking of broadcast 5 information. For instance, some countries may prohibit advertising for alcohol. Userterminais 22 produced for that country can be preset with a code, or a code can otherwise beloaded, so that the user terminais respond to the blocking signal and block the spécifieinformation. The blocking function can also be used to restrict the dissémination of sensitiveinformation (such as military or govemmental information), or to restrict revenue-bearing 10 broadcast services to certain users.

As stated previousîy, each coded program source is divided into individual prime ratechannels. As an example, an audio source may comprise four prime rate channels, whichrepresents an FM quality stéréo signal. Altematively, an audio source may comprise sixprime rate channels, which can be used as a “near CD” quality stéréo signal, or an FM quality 15 stéréo signal linked to a 32 bit data channel (e.g., for transmitting a signal for display on aradio receiver liquid crystal display (LCD)). As a further alternative, the six prime ratechannels can be used as a 96 kbps broadcast data channel. The image source may compriseonly one 16 kbps channel or several channels. As will be described in further detail below,user terminais 22, relying on ensemble information included in the TDM frame and in each 20 prime rate channel, preferably automatically select those prime rate channels necessarv togenerate the user-selected digital audio program or other digital service program.

In accordance with the présent invention, the transmission method employed at abroadcast station 26 incorporâtes a multiplicity of n Single Channel Per Carrier, FrequencyDivision Multiple Access (SCPÇ/FDMA) carriers into the uplink 28. These SCPC/FDMA 25 carriers are spaced on a grid of center frequencies which are preferably separated by 38,000Hertz (Hz) from one another and are organized in groups of 48 contiguous centerfrequencies or carrier channels. Organization of these groups of 48 carrier channels is usefulto préparé for demultiplexing and démodulation processing conducted on-board the satellite20. The various groups of 48 carrier channels are not necessarilv contiguous to one another. 3 0 The carriers associated with a particular broadcast channel (i.e., channel 59 or 67) are notnecessarilv contiguous within a group of 48 carrier channels and need not be assigned in the 15 Ο Ρι ΟI ' < same group of 48 carrier channels. The transmission method described in connection withFigs. 2 and 3 therefore allows for flexibility in choosing frequency locations and optimizesthe ability to fill the available frequency spectrum and to avoid interférence with other userssharing the same radio frequency spectrum. 5 Fig. 1 illustrâtes the overall operation of a System 10 for broadcasting Internet information, as well as other broadcast programs, in accordance with a preferredembodiment of the présent invention. In the case of the satellite processing payload, uplinksignais 28 issue from broadcasters via individual frequency division multiple access (FDMA)channels from broadcast stations 26 located anywhere within the terrestrial visibility of the 10 satellite 20 with élévation angles higher than 10°. Each broadcaster has the ability to uplinkdirectly from its own facilities to one of the satellites 20 by placing one or more 16 kbpsprime rate channels on the FDMA carriers. Altematively, broadcasters which hâve nocapacity for direct access to the satellite 20 may hâve access through a hub station. Forexample, the System gateway 23 can broadcast Web pages directly to one of the direct radio 15 broadcast satellites 20 or indirectly via a hub 27. Use of FDMA for the uplink 28 offers thehighest possible flexibility between multiple independent broadcast stations. ΙΠ. Satellite 20 The preferred satellites 20 of the direct radio broadcast System 10 cover the

African-Arabian région, the Asian région and the Caribbean and Latin American régionsfrom the following geostationary orbits: • 21°E orbital location, providing service to Africa and the Middle East. 25 · 95°W orbital location, providing service to Central and South America. • 105°W orbital location, providing service to Southeast Asia and thePacific rim.

Coverage for other areas, such as North America and Europe, can be provided withadditional satellites. 3 0 The direct radio broadcast System preferably uses the frequency band of 1467 to 1492 MHz, which has been allocated for Broadcasting Satellite Service (BSS) Direct Audio 15 Ο i i 62'.-

Broadcast (DAB) at WARC 92, that is, in accordance with resolutions 33 and 528 of the ITU.The broadcasters 26 use feeder uplinks in X band, from 7050 to 7075 MHz. Each satellite 20is preferably equipped with three downlink spot beams, having beamwidths of about 6°.Each beam covers approximately 14 million square kilometers within power distribution 5 contours that are 4 dB down from beam center and 28 million square kilometers withincontours that are 8 dB down. The beam center margin may be 14 dB based on a receivergain-to-temperature ratio of -13 dB/K.

Each satellite 20 carries two types of payloads. One is a “processing” payload thatregenerates the uplink signais 28 and assembles 3 TDM downlink carriers, and the other is a 10 “transparent" payload that repeats the uplink signais on 3 TDM downlink carriers 30. TheTDM signais 30 from the two payloads are each transmitted in 3 beams, with the processedand transparent signais in each beam having opposite circular polarization (LHCP andRHCP). Each TDM downlink signal 30 carries 96 prime rate channels in assigned time slots.

To a user terminal 22, ail of the TDM downlink signais 30 appear the same, except for 15 carrier frequency. The total capacity per satellite is 2 x 3 x 96 = 576 prime rate channels.

Conversion between uplink FDMA signais 28 and downlink multiple-channel-per- carrier, time division multiplex (MCPC/TDM) signais 30 in the direct radio broadcastSystem of Fig. 1 is achieved on board the satellite 20 bv an on-board processor. At thesatellite 20, each prime rate channel transmitted bv a broadcast station 26 is demultiplexed 20 and demodulated into individual 16 kbps baseband signais. Individual channels are routed viaa switch to one or more of the downlink beams 30, each of which is a single TDM signal.This baseband processing provides a high level of channel control in terms of uplinkfrequency allocation and channel routing between uplink and downlink. Uplink signais arereceived in the satellite in X band and converted to L band bv the on-board processor. The 25 downlinks 30 to the user terminais 22 use MCPC/TDM carriers. One such carrier is used ineach of the three beams on each satellite 20. The manner in which the direct radio broadcastsystem formats the FDMA uplinks and performs payload processing to generate the TDMdownlinks permits réception of a significant amount of data, including high Sound qualityaudio programs, using low cost receivers, among other advantages. 3 0 For the transparent payload, the TDM signais are assembled at a broadcast station and appear in precisely the same structure as do those assembled on board the satellite 20 bv the 17 0 ί Ί ΰ 2 9 processing payload. The TDM signal is sent to the satellite in th.e X band and is repeated inthe L band in one of the three downlink beams. The power level is the same for downlinkTDM signais generated by the processing payload. Thus, the technique for providing digitaldelivery of ail information services (e.g., voice, music, data, images and multimedia 5 information which can be obtained from the Internet) described herein and in accordancewith the présent invention is applicable to both the on-board processing and transparentpayloads. Processing such as the routing performed on-board the satellite 20 can occur at anearth station when using the transparent payload.

Fig. 4 illustrâtes the on-board re-allocation of prime rate channels from uplink 10 frequency division multiple access channels into a downlink MCPC/TDM channel in theprocessing payload of the satellite 20 of Fig. 1. The overall uplink capacitv is preferablybetween two hundred eighty-eight (288) and three hundred eighty-four (384) prime rateuplink channels 116 of 16.519 kbps each. Ninety-six (96) prime rate channels 118 are selectedand multiplexed for transmission in each downlink beam 30, and time division multiplexed 15 onto a carrier of approximately 2.5 MHz bandwidth as indicated at 120. Each uplinkchannel is routed to ail, some or none of the downlink beams. The order and placement ofprime rate channels in a downlink beam is fully selectable via a command link from atelemetry, range and control (TRC) facility 38, which is shown in Fig. 1.

Software is preferably provided at a broadcast station 26 or, if more than one 20 broadcast station 26 exists in the System 10, in a régional broadcast control facility (RBCF) 39to assign space segment channels in the uplink beam 28 to a satellite 20. The RBCF 39 ispreferably connected to the TRC facility 38 via a communication link. The softwareoptimizes use of the uplink spectrum by assigning PRC carriers whenever space is availablein the 48 channel groups. The carriers associated with a particular broadcast channel need 25 not be continuous within a group of 48 carrier channels and need not be assigned in the samegroup of 48 carrier channels.

The carrier frequencies in each downlink beam 30 are different to enhance beam-to-beam isolation. Each TDM downlink channel is operated in the satellite payload atsaturation, giving the highest possible power efficiency in tenus of link performance. Use of 3 0 single carrier per transponder operation achieves maximum efficiency in the operation of thesatellite communication payload in terms of conversion of solar power into radio frequency' 5 18 G'\ · 9 ('< i I Û L j 10 15 20 25 30 power. This is far more efficient than techniques requiring simultaneous amplification of amultiplicity of FDM carriers. The System produces high receive margins suitable forstationary and mobile réception indoors and outdoors.

The System 10 carries out audio source coding using MPEG 2.5, Laver 3 whichachieves the cited qualities at bit rates of 16, 32, 64 and 128 kbps, respectively, and alsoincludes the capability to perform 8 kbps coding. Image coding is carried out using the JPEGstandard. Error rates over the System are less than 1O'10 and thus are suitable for high qualitydigital image and data transmission for multimedia services. The MPEG 2.5, Laver 3 codingoffers a better bit rate efficiency than the previous MPEG 1, Layer 2 (Musicam) or MPEG 2standards for the same audio quality. For audio broadcasts, the digitally coded source bit ratesare: • 8 kbps for utility monophonie voice; • 16 kbps for non-utility monophonie voice; • 32 kbps for monophonie music, with near FM quality; • 64 kbps for stéréophonie music, with near FMquality; and • 128 kbps for stéréophonie music, with near CDquality.

In the preferred implémentation of the satellite direct radio broadeast System, eachsatellite 20 has the capacity to transmit a total of 3072 kbps per beam (including the 2 TDMcarriers for the processing and transparent payloads, respectively), which may be anycombination of the above audio services. This corresponds to a capacity per beam of: • 192 monophonie voice channels; or • 96 monophonie music channels; or • 48 stéréophonie music channels; or • 24 CD stéréophonie music channels; or • any combination of the above signal qualities.

Since the System 10 provides direct digital channels for digital dehvery of broadeast services,the System 10 can broadeast any type of data, images, moving images and other multimediadata via the satellites 20 such as information obtained from the Internet and multimediasources, as well as voice and music. In accordance with an aspect of the présent invention, - 1S -

CiΊό29 the System 10 can deliver to user terminais 22 push Internet information, that is, Internetinformation which is transmitted via the satellites 20 without requiring acknowledgmentfrom the user.

Theoverall satellite direct radio broadcast System delivers the digital signais with a bit 5 error rate (BER) of 104 or better, providing the various service qualities previously defined.For each downlink beam 30 in L band transmitted by the satellites 20, the Edge Of CoverageEERP of the TDM carrier is 49.5 dBW. This EIRP, together with spécifie Forward ErrorCorrection, insures a minimum 9 dB margin for a ÎO'’ BER, using the baseline radio receiverantenna. This margin helps combat signal loss due to obstacles in the path between the 10 satellite 20 and the receiver at the user terminal 22, providing full quality réception in theintended coverage area.

User terminais 22 in obstructed locations can be connected to a high gain antenna, orto an antenna located in an unobstructed position. For example, réception in large buildingsmay need a common roof antenna with indoor retransmission for the entire building, or 15 individual réception antennas near a window. At the 4 dB down contour of the earthcoverages, the channels hâve an estimated margin of 10 dB relative to the power densityneeded to deliver a bit error rate of 10-4. At beam center this margin estimate is 14 dB.

The operating margin of the direct radio broadcast System does not change for thehigher bit rates. Within the 4 dB contour, most user terminais 22 view the satellite 20 at 20 élévation angles of greater than 60°, making interférence from structures virtually nil. Insome beams, within the 8 dB contour the élévation angle to the satellite 20 is greater than50°, which may expérience occasional interférence due to reflections or blockage fromstructures. Line of sight réception even at low élévation angles (10° to 50°) is always possiblewith small 8 dBi gain antennas in some beams pointed toward the horizon. 25 As stated previously, the direct radio broadcast System includes a baseband processing payload in the satellite 20. Baseband processing allows improved System performance foruplink and downlink link budgets, management of broadcast stations, and control of thedownlink signais. Fig. 5 illustrâtes satellite signal processing in the satellite direct radiobroadcast System. The coded prime rate uplink carriers are received at an X-band receiver

3 0 122. A polyphasé démultiplexer and demodulator 124 receives the 288 individual FDMA signais in 6 groups of 48, generates six analog signais on which the data of the 288 signais is 20 divided into 6 time multiplexed streams, and perforais démodulation of the serial data on each stream. A routing switch and modulator 126 selectively routes individual channels of the serial data into ail, some or none of three downlink signais, each carrying 96 channels, and further modulâtes them onto the three downlink L-band TDM signais. Traveling wave 5 tube amplifiers 128 boost the power of the three downlink signais, which are radiated toearth by L-band transmit antennas 130. The transparent payload also comprises adémultiplexer and downconverter 132 and an amplifier group 134, which are configured in aconventional “bent pipe” signal path to frequency convert uplink TDM/MCPC signais forretransmission at L band. 10 The satellites 20 are operated by a ground control segment (e.g., the software available at a single broadcast station 26 or a RBCF 39 servicing a number of broadcast stations 26) andmanaged according to traffic requirements by a mission control segment during the orbitlifetime. The bit rates and consequently the service qualities can be mixed in any beam tomeet the demand for service. The bit-rate/quality complexion of a service can be easily 15 changed from ground command and can vary at different times of the day. In the preferredembodiment, channel allocation can be changed on an hour-by-hour basis according to aprogram schedule established twenty-four hours in advance. It is to be understood, however,that channel allocation can be changed on a more or less frequent basis.

With reference to Fig. 2, within each QPSK modulation block 86, a separate QPSK 20 modulator modulâtes each prime rate channel to an intermédiare frequency. Theupconverter 88 moves the separate prime rate channels to the FDMA uplink band, and theupconverted channels are transmitted through amplifier 90 and antenna 91. Broadcast uplinkstations preferably use VSAT signais for transmission of elementary (16 kbps) channels, usingsmall antennas (2 to 3 meters in diameter). 25 The prime rate uplink channels are transmitted to the satellite 20 on individual FDMA carriers. As stated previously, up to 288 uplink prime rate carriers can betransmitted to the satellite 20 in its global uplink beam. Small broadcasters’ earth terminaisequipped with 2.4 meter diameter parabolic X-band antennas and 25 watt power amplifierscan easily transmit a 128 kilobit per second program channel (comprising 8 of the prime rate

3 0 channels) to the satellite 20 from a site in the country originating the program. Altematively,program channels can be connected to shared uplink earth terminais via leased PSTN 21 01Ί329 terrestrial links. The System has adéquate uplink capacity for every countrv in its worldcoverage to hâve its own satellite radio broadcasting channel. IV. User Terminais 5 A block diagram of one of the user terminais 22 of Fig. 1 is provided in Fig. 6. The user terminal 22 receives the L band signal from the satellite 20, démodulâtes and extractsfrom the TDM stream the useful audio, data or image signal, and reproduces the desiredaudio data or image information. The user terminal may be equipped with a small compactpatch antenna 136 having about 4 to 6 dBi gain, which will require virtually no pointing. 10 The user terminal 22 tunes automatically to selected channels.

As stated previously, time division multiplexed, multiple channel per carrier techniques (MCPC/TDM) are used for downlink transmission to the user terminal 22. Eachof the prime rate channels occupies its own time slot in the time division stream. Theseprime rate channels are combined to carry program channels ranging from 16 to 128 kilobits 15 per second. Use of digital techniques allows for ancillary services to the radio including lowrate video, paging, mailing, fax, use of fiat display screens, or serial data interfaces. This dataand information may be multiplexed within the audio digital signal channels. In addition,the prime rate channels can carry program channels that are primarily screens (e.g., ahomepage from the WWW) for display at the user terminal with or without an audio 2 0 program, and downloaded data for storage and/or printing.

Each user terminal 22 can tune to one of the TDM carriers transmitted in one of the beam coverages. As shown in Fig. 6, the user terminal 22 inciudes a digital broadcastreceiver 21, an antenna 136, and a computer 29. The receiver 21 can be connected to a serialport of the computer 29, for example. An Internet service provider such as the System 25 gateway 23 of Fig. 1 can operate in one, two or ail of the beam coverages of the threesatellites 20. The System 10 can change the FDM uplinks 28 assigned to an Internet serviceprovider and the manner in which the information is routed on-board the satellite 20 to oneor more of the downlink beams 30 via software and telemetry control.

Within the digital broadcast receiver 21, a low noise amplifier 138 boosts the satellite 30 signal, and the boosted signal is received by an RF front end and QPSK demodulator 140.The output of the RF front end and QPSK demodulator 140 can bé connected to a first time 22 Οι1 ό2ί division démultiplexer 142 which recovers the audio prime rate channels (PRCs), and to asecond time division démultiplexer 144 which recovers the prime rate channels carrying data,including images.

After the n PRCs of a received broadcast channel are realigned, the symbols of each 5 PRC are remultiplexed into an FEC-coded broadcast channel using blocks 142 and 144. Theoutput of the block 142 is a baseband digital signal carrying audio information, and theoutput of the block 144 is a baseband digital signal carrying data.

The recombined coded program channels thus recovered are decoded anddeinterleaved to recover the original baseband prime rate bit stream that entered the System 10 at the broadcaster's earth station 26. In the case of audio data, the recovered bit streams areconverted back to an analog audio signal by an audio décoder 146 and a digital-to-analogconverter 148. The analog signal is boosted by an amplifier 150 and is reproduced by aloudspeaker 152. The user terminal can reproduce various audio qualities ranging from AMmonaural to CD stéréo depending on the program channel bit rate. In the case of data, the 15 recovered bit streams can be converted to a displayable format by an data/image décoder 154.In addition to being displayed, the received data can be saved to a memory device or printed.

The instructions needed for the user terminal 22 to control recombination of thecoded prime rate channels into the coded program channels are preferably contained in thecontrol words embedded in each coded prime rate channel and in the original baseband 20 prime rate bit stream (e.g., in the SCH or the PRC pream'ole). The receiver 21 isprogrammed to process the instructions in the control words.

In accordance with one embodiment of the présent invention, a SCH 102 is providedin each BC, as shown in Fig. 3. Data from the data décoder 154, including the broadcastchannel and the SCH, is provided via a broadcast channel input/output (BCIO) port to the 25 computer 29. The computer 29 stores the data on a disk drive 176 (Fig. 6). The computerprocesses the data to examine the packets. Packet information is compared with usersélections made using the keypad 170, mouse 174 or other input device connected to thecomputer 29 to détermine which of the stored packets are to be used for output purposes.The information identification data can be provided as pan of the service control headers 102 3 0 identifies packets originating from the same Internet source. 23 Ο ί Ί 0 2 ζ

The principal components of the computer 29 include a microprocessor 156 havingsuitable amounts of random access memory (RAM) 160 and read-onlv memorv (ROM) 162,a real-time clock 164 and a display controller 166. The display controller 166 Controls theformatting of image data (e.g., Web page data) to a display 168. The microprocessor 156 is 5 preferably also connected to a kevpad 170, a printer/plotter 172, a mouse 174 and a diskdrive 176. A microprocessor input/output (I/O) interface 158 is illustrated to represent theserial and parallel ports of the microprocessor 156. As shown in Fig. 6, the data decoded bythe receiver 21 can be provided to the computer 29 via a serial port connection. The keypad170 and the mouse 172 are used for selecting broadcast programs, controlling sound levels, 10 making menu sélections, and similar functions. Menus and screens can be generated on thedisplay 168 in accordance with program code for the microprocessor 156 or a received Webpage. The printer/plotter 172 allows the user to receive a hard copy output of any receiveddata (including images), in addition to viewing the data on the display 168. Finally, the diskdrive 176 allows data or programs to be loaded into the computer 29, and also allows 15 received data (e.g., Web pages) to be stored for later viewing, and listening and printing.Another possible function of the disk drive 176 may be, for example, to allow the computer29 to merge images or other data that are being received in real-time by the digital broadcastreceiver 21 with preexisting data stored on a magnetic diskette. This is useful, for example, inallowing an existing image or other data to be updated by transmitting onlv the new or 2 0 modified information, without requiring the existing image or data to be retransmitted.

The components of Fig. 6 can be incorporated into a single unit that is designed forportable or mobile use. Altematively, as shown in Fig. 1, the receiver 21 can be a portabledevice connected to a separate computer 29. Power may be provided by batteries, solar cellsor a generator driven by a spring motor or hand crank. If the user terminal 22 is carried by 25 vehicle such as a boat, aircraft or automobile, power may be provided by the vehicle’s powersupply. As an alternative to housing ail of the components of the user terminal 22 in a singlecase, the user terminal 22 may be made up of a System or network of separate componentsinterconnected by suitable cables.

Fig. 7 is a flow chart which summarizes the basic sériés of operations carried out by 3 0 the user terminal 22 of Fig. 5 when audio and data programs are received. It will be understood that, due to the TDM format of the downlink channels 50, the user terminal 22 is 24 Q! 1o29 capable of receiving and reproducing audio programs and data simultaneously. Thus, theuser is not required to stop listening to an audio program in order to receive images or othertypes of data. As a resuit, a user who wishes to obtain selected data from the Internet, forexample, can do so while continuing to listen to audio programs on the audio program 5 channel.

With spécifie reference now to the logic sequence shown in Fig. 7, the first step in theprogram is to power-up and initialize the receiver 21 and the computer 29 (block 180). Thereceiver 21 is tuned to receive one of the three TDM downlinks 30 (block 182). The receiverdémultiplexes and décodés prime rate channels from the received downlink 30 and 10 remultiplexes them into a broadeast channel including its SCH 102. The broadeast channelcan comprise a real-time audio and video programs. The user terminal commences playbackof the audio program on the speaker 152, and display of the video program on the display168 (block 184). The broadeast channel can also contain Internet information which is storedfor use in non-real-time on the disk drive 176. The computer 29 generates a screen 220, 15 which is illustrated in Fig. 8, on the display 168 (block 186). The screen 220 is an initialbrowser screen which provides the user with a list of different topics of information derivedfrom the Internet broadeast.

The screen 220 can provide an icon and corresponding name for such topics ofinformation as new reports, weather, stock market rates, consumer catalogs, geographical 20 maps, and so on. The user can select one of the topics using the keypad 170, the mouse 174 orother input device (block 188).

In accordance with a preferred embodiment of the présent invention, storedinformation identifying the type of packet data obtained from the SCH 102 is processed bythe computer 29 to select and display the type of Internet information selected by the user 25 (blocks 190 and 192). As indicated by the affirmative branch of decision block 194 and block196, the computer extracts the packets matching the user’s sélection and generates a screen onthe display 168 in accordance with the packets (block 198). For example, the packets cancomprise data to create a Web page or a simple computer screen with text and no graphies, orvideo data. In addition, some of the packets can comprise a sound byte which can be 30 provided to an auxiliary speaker 178 that is connected directly to the computer. If theselected data is accompanied by a sound byte, playback of the audio program via the speaker 25 Ο ί Ί ο 2 9 152 can be simultaneous with the playback the Sound byte. Packets whose informationidentification data do not correspond to the user sélection in the screen 220 are ignored bvthe computer 29 (block 196).

The topics of information currently stored on the disk drive 176 are displayed on the 5 screen 220. In the meantime, the disk drive 176 can store a new set of Internet informationthat is currently being received for later viewing by the user. Thus, the disk drive stores newInternet information, while allowing the user to retrieve and view information that hasalready been stored. The computer can also store information for later use in real-timeapplications such as distance leaming. 10 The System 10 of the présent invention is advantageous because it provides digital delivery channels for broadcasting voice, music, different types of data such as images andmoving images, and multimedia information to remote user terminais. Thus, user terminaishaving no access to the Internet can receive push Internet information, that is, broadcastInternet information which does not require acknowledgment from the remote user. In 15 accordance with another aspect of the présent invention, the user terminal can be providedwith a terrestrial link, e.g., a public switched téléphoné network (PSTN) link, tocommunicate with an information provider. For example, the user can receive a broadcasteducational program comprising voice, text and image data from a distance leaming centervia a satellite 20. The user can send responses to the educational program to the distance 2 0 leaming center or another site via the PSTN link. This configuration is advantageous whenthe PSTN link lacks sufficient bandwidth to carry the voice, texx and image data of theprogram.

Although the présent invention has been described with reference to a preferredembodiment thereof, it will be understood that the invention is not limited to the details 25 thereof. Various substitutions and modifications hâve been suggested in the foregoingdescription, and others will occur to those of ordinary skill in the art. Ail such substitutionsand modifications are intended to be embraced within the scope of the invention as definedin the appended daims.

Claims (9)

1. -26- 011629 What Is Claimed Is

   1. A System for providing user terminais with information from at least oneremote communication network comprising: a receiver; 5 a satellite configurée! to receive a broadeast channel comprising packets containing said information, said information relating to at least one of a plurality oftopics, said broadeast channel comprising data indicating which of said packets whichcorrespond to of said plurality of topics, said satellite being opérable to transmit saidbroadeast channel to said receiver; a processing device connected to said receiver; a user input device connected to said processing device; and a display device connected to said processing device, said processing device being programmable to generate a screen on said display device to prompt a user to select oneof said plurality of topics, said receiver being opérable to provide said packets to said 15 processing device, said processing device being opérable to process an input signal generated by said user input device when said user makes a sélection using said screenand to examine said data to détermine which of said packets correspond to an inputsignal, said display device being controlled by said processing device to displav saidinformation corresponding to said input signal. gQ 2. A System as claimed in claim 1, further comprising a multimedia device connected to said receiver, said information comprising at least one of data, graphies, staticimages, moving images text. audio, web pages, and video, said multimedia device beingopérable to perform at least one of a plurality of operations depending on said input signalcomprising displaying at least one of said data, said graphies, said static images, said moving 25 images, said text, said web page and said video and playing said audio.
2. 3. A System as claimed in daim 1, further comprising at least one of an Internetservice provider computer and a System gateway connected to said remote communicationnetwork, and a broadeast station connected to said at least one of an Internet serviceprovider and a system gateway, said broadeast station being opérable to receive said 30 information from said at least one of an Internet service provider and a system gatewav, to format said information into said broadeast channel with said data indicating to which of -27 - said plurality of topics said packets correspond, and to transmit said broadcast channel tosaid satellite.
3. 4. A System as claimed in claim 3, further comprising a hub for connecting saidbroadcast station to said System gatewav. 10 15 20
4. 5. A method of broadcasting information from Internet service providers to userterminais comprising a radio receiver and a multimedia device via satellite and without abackhaul link between the user terminais and the service providers: formatting a broadcast channel comprising packets of Internet informationrelating to a plurality of topics and identification data for transmission to said userterminais, said identification data identifying to which of said plurality of topics saidpackets correspond; transmitting said broadcast channel to said user terminais via said satellite;receiving said broadcast channel at a number of said user terminais;generating a menu using said multimedia device to list said plurality7 of topics;determining a user input signal corresponding to a sélection of one of said plurality of topics from said menu; determining which of said packets corresponds to said user input signal usingsaid identification data; and outputting said packets corresponding to said user input signal using saidmultimedia device.
5. 6. A method as daimed in claim 5, wherein said formatting step comprises the stepof formatting Internet information comprising at least one of news, weather reports, stockmarket rates, educational programs and consumer information.
6. 7. A method as daimed in daim 6, wherein said generating step of: identifying at least one of said news, said weather reports, said stock market raies,said educational programs and said consumer information using said multimedia device asmenu options: and providing a prompt for instructing a user to select one of said menu options. 25 Οι1^29 - 2-3 -
7. 8. A method as claimed in daim 5. uherein said formaning step further comprisesthe step of formaning program information indicating said plurality oi topics andcorresponding broadcast unies for réception at said user terminais.
8. 9. Λ method as claimed in daim 8, svherein said user terminais are programmed toupdate said menu using said program information.
9. 13. Λ satellite broadcast communication System for broadcasting Internetinformation comprising: a plurality of receivers: at least one broadcast station for transmitting a broadcast channel comprisingpackets of different rvpes of Internet information and data identifying uhich of saidpackets correspond to u hicli of said different types of Internet information: and a satellite for receiving said broadcast channel and for transmitting said broadcastchannel to said plurality of receivers; u herein at least one of said pluraJityof receivers receives said broadcast channel.said receiver comprising a multimedia device having a memory device for storing packets obtained from said broadcast channel, an otitput device for prompting a user to make a sélection from aplurality ol different types of Internet information; an input device to allosv a user to make said sélection, and 20 a processor programmed to retrieve seleaed ones of said packets storedin said memory deuce winch correspond to said selectinn and provide saidselected one< ol said packets to said output device.