KR101243194B1 - A system and method for grouping program identifiers into multicast groups - Google Patents

Abstract

The disclosed embodiments are directed to a system and method for grouping program identifiers into multicast groups. More specifically, receiving a request for satellite service from the requester device 22, the request comprising at least one program identifier; Creating a second group of program identifiers; Comparing the requested program identifier with a previously requested program identifier of a first group stored on the satellite service providing device 14; If the requested program identifier matches one of the program identifiers in the program identifier of the first group, moving the matched program identifier from the program identifier of the first group to the program identifier of the second group, wherein A multicast of program identifiers is provided, comprising moving, adapted to be shared by the requestor device 22 and another device.

Description

SYSTEM AND METHOD FOR GROUPING PROGRAM IDENTIFIERS INTO MULTICAST GROUPS}

The present invention is generally directed to transmitting video or other digital data over a network. More particularly, the present invention is directed to a system for grouping program identifiers ("PIDs") into multicast groups for Internet Protocol ("IP") delivery to provide uninterrupted services to clients.

This section is intended to introduce the reader to various aspects of the prior art, which may relate to various aspects of the present invention described below and / or claimed. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Therefore, it should be understood that such sentences should be read in this respect and not as admissions of the prior art.

As most people know, satellite television systems such as DirecTV have become much more widespread in the past few years. In fact, since the introduction of DirecTV in 1994, more than 12 million American homes have become satellite TV subscribers. Most of these subscribers live in single-family homes, which are relatively easy to install and connect with satellite dish antennas. For example, a satellite dish antenna may be installed on the roof of the house.

However, many potential subscribers live or temporarily live in multi-dwelling units (“MDUs”), such as hotels or high-rise apartment buildings. Unfortunately, there are additional challenges involved in providing satellite TV service to individual generation units within the MDU. Providing and connecting one satellite dish antenna per generation can be unrealistic and / or very expensive. For example, in a high-rise apartment building with 1,000 apartments, it may be impractical to mount 1,000 satellite dish antennas on the roof of the building. Some of the prior art systems have avoided this problem by converting digital satellite television signals into analog signals that can be transmitted to multiple generations over a single coaxial cable. However, these systems offer limited channels, degrade quality compared to all-digital systems, and cannot provide a familiar satellite TV experience for users living in single-family homes.

Improved systems and / or methods for providing satellite TV to multigenerational units are desirable.

Certain aspects that fall within the scope of the originally claimed invention are described below. It is to be understood that this aspect has been presented solely to provide the reader with a brief summary of the specific forms the invention may take, and that such aspects are not intended to limit the scope of the invention. Indeed, the invention may encompass a variety of aspects that may not be described below.

The disclosed embodiments are directed to a system and method for grouping program identifiers into multicast groups. More specifically, receiving a request for satellite service from the requester device 22, the request comprising at least one program identifier; Creating a second group of program identifiers; Comparing the requested program identifier with a previously requested program identifier of a first group stored on the satellite service providing device 14; If the requested program identifier matches one of the program identifiers in the program identifier of the first group, moving the matched program identifier from the program identifier of the first group to the program identifier of the second group, wherein A multicast of program identifiers is provided, comprising moving, adapted to be shared by the requestor device 22 and another device.

Advantages of the present invention may become more apparent upon reading the following detailed description and referring to the drawings below.

1 is a block diagram of an exemplary satellite television on an IP system in accordance with an embodiment of the present invention.

2 is another embodiment of an exemplary satellite television on the IP system illustrated in FIG.

3 is a block diagram of an exemplary satellite gateway of the present invention.

4 is a flow diagram illustrating an exemplary technique for grouping program identifiers into a multicast group, in accordance with an embodiment of the invention.

One or more specific embodiments of the invention will be described below. In an effort to provide a brief description of these embodiments, not all features of an actual implementation are described herein. In the development of any such actual implementation, as in any engineering or design project, the developer achieves certain goals, such as compliance with systems-related and business-related constraints, which may vary from implementation to implementation. A number of implementation-specific decisions must be made to accomplish this. In addition, while such development efforts may be complex and time consuming, it should nevertheless be appreciated that it is an ever-presenter of design, fabrication, and manufacturing to those skilled in the art having the benefit of this disclosure.

1, a block diagram of an exemplary satellite television on an IP system is described and generally designated by reference numeral 10, according to one embodiment. As described, in one embodiment, system 10 includes one or more satellite dish antennas 12a through 12m, a head-end unit such as satellite gateway 14, IP distribution network 20, and one or more set top boxes. ("STB") (22a through 22n). However, those skilled in the art will recognize that the embodiment of the system 10 described in FIG. 1 is only one potential embodiment of the system 10. As such, in alternative embodiments, the described components of system 10 may be rearranged or omitted, or additional components may be added to system 10. For example, via mirror modification, system 10 may be configured to distribute non-satellite video and audio services.

Satellite dish antennas 12a-12m may be configured to receive video, audio, or other types of television-related data transmitted from satellites orbiting the earth. As described further below, in one embodiment, satellite dish antennas 12a-12m are configured to receive DirecTV programming on the KU band from 10.7 to 12.75 gigahertz (“GHz”). However, in an alternative embodiment, the satellite dish antennas 12a-12m may be other types of direct broadcast satellites ("DBS") or television receive-only: dish antenna network signals, ExpressVu signals, StarChoice signals, or the like. "TVRO") signal. In another non-satellite based system, satellite dish antennas 12a-12m may be omitted from system 10.

In one embodiment, the low noise-to-block converter (“LNC”) within the satellite dish antennas 12a-12m receives input signals from satellites orbiting the earth and converts the input signals to 950 and 2150 MHz (“MHz”). Convert to a frequency in the L band between "). As described in more detail below with respect to FIG. 2, each of the satellites 12a-12m receives one or more input satellite TV signals with special polarizations on a particular frequency (referred to as transponders) to L-band the satellite signals. Configured to convert to a signal, each of which L-band signals may comprise a plurality of video or audio signals.

The satellite dish antennas 12a-12m may be configured to transmit L band signals to a head-end unit or gateway server, such as satellite gateway 14. In alternative non-satellite embodiments, the head-end unit may be a cable television receiver, a high definition television receiver or other video distribution system.

The satellite gateway 14 includes a satellite tuning, demodulation and demultiplexing module 16 and an IP wrapper module 18. Module 16 may include a plurality of tuners, demodulators and demultiplexers for converting the modulated and multiplexed L band signals transmitted from satellites 12a-12m into a plurality of single program transport streams ("SPTS"). Each of the plurality of single program transport streams carries a service (eg, television channel video, television channel audio, program guide, etc.). In one embodiment module 16 is configured to generate a single program transport stream for all services received by satellite dish antennas 12a-12m. However, in an alternative embodiment, module 16 may only generate a transport stream for a subset of services received by satellite dish antennas 12a-12m.

The satellite tuning, demodulation and demultiplexing module 16 may send the SPTS to the IP wrapper module 18. In one embodiment, IP wrapper module 18 repackets data in SPTS into a plurality of Internet Protocol ("IP") packets suitable for transmission on IP distribution network 20. For example, IP wrapper module 18 may convert DirecTV protocol packets in the SPTS into IP packets. IP wrapper module 18 also receives server requests from STBs 22a-22n and multicasts IP SPTS to the STBs 22a-22n that requested this particular service (i.e. one or more on the IP address). Broadcast to STBs 22a-22n.

In alternative embodiments, IP wrapper module 18 may also be configured to multicast IP protocol SPTS for services not requested by one of STBs 22a-22n. It should be noted that modules 16 and 18 are just one exemplary embodiment of satellite gateway 14. In alternative embodiments as described below with respect to FIGS. 2 and 3, the functionality of modules 16 and 18 may be redistributed or integrated between various suitable components or modules.

The IP distribution network 20 may include one or more routers, switches, modems, splitters, or bridges. For example, in one embodiment, satellite gateway 14 is a master distribution frame coupled to an intermediate distribution frame (" IDF ") coupled to a coaxial cable to an Ethernet bridge coupled to a router coupled to one or more STBs 22a-22n. ("MDF"). In another embodiment, IP distribution network 20 may be an MDF coupled to a digital subscriber line access multiplexer (“DSLAM”) coupled to a DSL modem coupled to a router. In another embodiment, the IP distribution network may comprise a wireless network, such as an 802.11 or WiMax network. In this type of embodiment, the STBs 22a-22n may include a wireless receiver configured to receive multicasted IP packets. Those skilled in the art will recognize that the embodiments described above are merely illustrative. As in alternative embodiments, many suitable forms of IP distribution networks may be used in the system 10.

The IP distribution network 20 may be connected to one or more STBs 22a-22n. The STBs 22a-22n may be any suitable type of video, audio, and / or other data receiver capable of receiving IP packets such as IP SPTS on the IP distribution network 20. It will be appreciated that the term set top box ("STB") used herein does not include only devices that can be placed on a television. Rather, the STBs 22a-22n may be any device or device, internal or external to a television, display, or computer, which may be configured to function as described herein, such device or device being, without limitation. , Video components, computers, cordless phones, or other forms of video recorders. In a particular embodiment, the STBs 22a-22n may also be known as an integrated receiver device (“IRD”).

In one embodiment, the STBs 22a-22n may be DirecTV receivers configured to receive services, such as video and / or audio, over Ethernet ports (among other inputs). However, in alternative embodiments, the STBs 22a-22n may be coaxial cable, twisted pair, copper conductors, or I.E.E.E. Through a wireless standard such as the 802.11 standard, it can be designed and / or configured to receive wirelessly multicasted transmissions.

As discussed above, system 10 may receive video, audio and / or other data sent to satellites in space and process / transform such data for distribution on IP distribution network 20. have. Thus, FIG. 2 is another embodiment of an exemplary satellite television on IP system 10 according to one embodiment. 2 illustrates three exemplary satellite dish antennas 12a-12c. Each of the satellite dish antennas 12a-12c may be configured to receive signals from one or more satellites that orbit. Those skilled in the art will appreciate that satellites and signals transmitted from satellites are often referenced by orbital slots in which the satellites are located. For example, satellite dish antenna 12a is configured to receive signals from DirecTV satellites arranged in 101 degree orbit slots. Similarly, satellite dish antenna 12b receives signals from satellites arranged at 119 degrees, and satellite dish antenna 12c receives signals from satellites arranged in orbit slots of 110 degrees. In alternative embodiments, satellite dish antennas 12a-12c may receive signals from a plurality of other satellites represented in various orbital slots, such as 95 degree orbital slots. The satellite dish antennas 12a-12c may also be configured for receiving polarized satellite signals. For example, in FIG. 2, the satellite dish antenna 12a is configured to receive a signal polarized to the left (indicated by " 101L " in FIG. 2) and also polarized to the right (indicated by " 101R ").

As described above with respect to FIG. 1, satellite dish antennas 12a-12c may receive satellite signals in the KU band and convert them into L band signals transmitted to the satellite gateway 14. However, in some embodiments, the L band signal generated by the satellite dish antennas 12a-12c may be merged into fewer signals or split into more signals before reaching the satellite gateway 14. . For example, as illustrated in FIG. 2, the L band signal from satellite dish antennas 12b and 12c may be a single L band signal that includes L band signals from both a satellite at 110 degrees and a satellite at 119 degrees. It can be incorporated by the switch 24.

As described, system 10 includes a plurality of 1: 2 dividers 26a, 26b, 26c and 26d to split the L band signal transmitted from satellite dish antennas 12a-12c into two L band signals. And each of the two L band signals includes half of the services of the pre-divided L band signal. In alternative embodiments, the 1: 2 dividers 26a-26b may be omitted or integrated into the satellite gateways 14a and 14b.

The newly divided L band signal may be transmitted from the 1: 2 dividers 26a-26d to the satellite gateways 14a and 14b. The embodiment of the system 10 described in FIG. 2 includes two satellite gateways 14a and 14b. However, in alternative embodiments, system 10 may include any suitable number of satellite gateways 14. For example, in one embodiment, the system may include three satellite gateways 14.

The satellite gateways 14a and 14b then further subdivide the L band signals, one on the L band signal to generate one or more SPTSs that can repacket the IP packets and multicast on the IP distribution network 20. We can synchronize with the above service. In addition, one or more satellite gateways 14a, 14b may also be connected to a public switched telephone network (“PSTN”) 28. Since the satellite gateways 14a and 14b are connected to the PSTN 28, the STBs 22a-22n can communicate with the satellite service provider via the IP distribution network 20 and the satellite gateways 14a and 14b. This function can advantageously eliminate the need to have each individual STB 22a-22n connected directly to the PSTN 28.

IP distribution network 20 may also be connected to an Internet service provider (“ISP”) 30. In one embodiment, IP distribution network 20 is used to provide Internet services, such as high speed data access, to STBs 22a-22n and / or other suitable devices (not shown) connected to IP distribution network 20. Can be.

As described above, the satellite gateways 14a and 14b may be configured to receive a plurality of L-band signals to generate a plurality of SPTSs and to multicast the requested SPTS on the IP distribution network 20. Referring now to FIG. 3, shown is a block diagram of an example satellite gateway 14. As described, the satellite gateways 14a and 14b include a power supply 40, two front ends 41a and 41b and a rear end 52. The power source 40 can be any one of a number of industry-standard AC or DC power sources that can be configured to allow the front end 41a, 41b and the rear end 52 to perform the functions described below. .

The satellite gateways 14a and 14b may also include two front ends 41a and 41b. In one embodiment, each front end 41a, 41b may be configured to receive two L band signal inputs from the 1: 2 dividers 26a-26d described above with respect to FIG. 2. For example, the front end 41a may receive two L-band signals from the 1: 2 divider 26a, and the front end 41b may receive two L-band signals from the 1: 2 divider 26b. can do. In one embodiment, each of the L band inputs to the front ends 41a, 41b includes up to eight services.

The front end portions 41a and 41b can then further subdivide the L band input using 1: 4 L band dividers 42a, 42b, 42c and 42d. Once subdivided, the L band signal can be delivered to four banks 44a, 44b, 44c and 44d of the dual tuner link. Each of the dual tuner links in banks 44a-44d may be configured to tune to two services in the L band signal received by the respective dual tuner link to produce an SPTS. Each of the dual tuner links may then send the SPTS to one of the low voltage differential signal (“LVDS”) drivers 48a, 48b, 48c, and 48d. LVDS drivers 48a-48d may be configured to amplify a transport signal for transmission to the rear end 52. In alternative embodiments, other types of differential drivers and / or amplifiers may be used in place of the LVDS drivers 48a-48d. Other embodiments may use the serialization of all transport signals together to direct to the rear end 52.

As described, the front end portions 41a and 41b may include microprocessors 46a and 46b. In one embodiment, the microprocessors 46a and 46b may control the banks 44a-44d and the 1: 4 L band dividers 42a-42d of the dual tuning link and / or relay the commands. Microprocessors 46a and 46b may include ST10 microprocessors produced by ST Microelectronics. Microprocessors 46a and 46b may be connected to the LVDS receiver and transmitter modules 50a and 50b. The LVDS receiver / transmitter modules 50a and 50b may assist in communication between the components of the microprocessor 46a and 46b and the rear end 52, as described further below.

Turning next to the back end 52, the back end 52 includes LVDS receivers 54a, 54b, 54c and 54d configured to receive transport stream signals transmitted by the LVDS drivers 48a-48d. do. The rear end 52 also includes LVDS receiver / transmitter modules 56a and 56b configured to communicate with the LVDS receiver / transmitter modules 50a and 50b.

As described, LVDS receivers 54a-54d and LVDS receivers / transmitters 56a, 56b are configured to communicate with transport processors 58a and 58b. In one embodiment, the transport processors 58a, 58b are configured to receive the SPTS generated by the dual tuner links in the front ends 41a, 41b. For example, in one embodiment, the transport processors 58a, 58b may be configured to generate 16 SPTSs. Transport processors 58a and 58b may be configured to repacket the SPTS into IP packets that may be multicast on IP distribution network 20. For example, transport processors 58a and 58b may repacket DirecTV protocol packets into IP protocol packets to multicast these IP packets on one IP address to one or more STBs 22a-22n.

Transport processors 58a and 58b may also be connected to a bus 62, such as a 32-bit, 66 MHz peripheral component interconnect (“PCI”) bus. Via bus 62, transport processors 58a and 58b may communicate with network processor 70, Ethernet interface 84, and / or expansion slot 66. The network processor 70 may be configured to receive a request for a service from the STBs 22a-33n and direct the request to the transport processor 58a, 58b for multicasting the requested service. In one embodiment, the network processor is an IXP425 network processor produced by Intel. Although not described, the network processor 70 may also be configured to transmit status data to the front panel of the satellite gateways 14a and 14b, or to support debugging or monitoring of the satellite gateways 14a and 14b through debug ports. Can be.

As described, the transport processors 58a and 58b may also be connected to the Ethernet interface via the bus 62. In one embodiment, the Ethernet interface 68 is a gigabit Ethernet interface that provides a copper lead or fiber optic interface to the IP distribution network 20. In addition, the bus 62 may also be connected to an expansion slot such as a PCI expansion slot to enable upgrade or expansion of the satellite gateways 14a and 14b.

Transport processors 58a and 58b may also be connected to a host bus. In one embodiment, host bus 64 is a 16-bit data bus that connects transport processors 58a and 58b to modem 72, which may be configured for communication on PSTN 28, as described above. to be. In alternative embodiments, modem 72 may also be connected to bus 62.

As described above, the satellite gateway 14 receives services such as television, video, audio, or other data and multicasts these services through the IP distribution network 20 to the STBs 22a-22n. Can be configured. In one embodiment, satellite gateway 14 multicasts services by grouping related services into a single multicast. For example, if one of the STBs 22a-22n requests video and audio for ABC television broadcasts, one of the satellite gateways 14 may be able to multicast to a particular IP address. As a multicast group, program identifiers for the video portion of ABC can be grouped together with program identifiers for the audio portion of ABC. If one of the STBs 22a-22n wants to watch the same ABC broadcast with the same audio, the satellite gateway 14 may access this IPB associated with the previously created multicast group. ) Can be instructed.

The technique described above is well suited for creating multicast groups when the program identifiers have a static relationship. However, as described below, if the program identifier relationship becomes more complex, additional techniques may be beneficial. For example, the above-described ABC broadcast is requested not only by one of the STBs 22a-22n requesting the ABC broadcast but also by the STB 22a- requesting the split-screened NBC broadcast with the ABC broadcast. 22n), as well as one of the STBs 22a-22n requesting a screen-divided CBS with ABC. In this situation, creating one multicast group including only ABC broadcasts, another multicast group including NBC broadcasts and ABC broadcasts, and another multicast group including ABC broadcasts and CBS broadcasts It can be an inefficient use of bandwidth.

Thus, FIG. 4 is a flow diagram illustrating an example technique 80 for grouping program identifiers into a multicast group, according to one embodiment. As described in block 82, the method 80 may begin by setting the counter SPTSNum to zero and clearing the set of system program identifiers (“PIDs”) referred to as system PIDsets. The system PIDset may be an array of PIDsets that are currently multicast or previously multicast by the satellite gateway 14. Next, the satellite gateway may generate a collision PIDset, indicated as block 83. In one embodiment, satellite gateway 14 may generate one collision PIDset for each transponder being received by satellite gateway 14. However, in alternative embodiments, other criteria may be used to generate the collision PIDset.

After generating the collision PIDset, the satellite gateway 14 receives a request from one of the STBs 22a-22n that includes the PID for one or more services of the STBs 22a-22n, as indicated at block 84. Can be received (see FIG. 1). Once the satellite gateway 14 has received the PID request, this satellite gateway can group the requested PIDs into a temporary PIDset for the requesting STB, referred to as the client PIDset, as indicated in block 86.

After grouping the requested PIDs, as indicated at block 88, satellite gateway 14 may determine whether the number of SPTSs is greater than zero. If the number of SPTSs is equal to zero (ie not greater than zero), the method 80 advances to block 102, as described below. If the number of SPTSs is greater than zero, however, the satellite gateway 14 determines whether the client PIDset intersects the system PIDset as indicated at block 90 (i.e., any PID in the client PIDset matches any PIDset in the system PIDset array). Will be determined). If the client PIDset does not intersect the system PIDset, the method 80 will advance to block 102, as described further below.

However, if the client PIDset indeed crosses the system PIDset, the satellite gateway 14 will determine if the client PIDset crosses more than one system PIDset at more than one PID, as indicated at block 92. If the client PIDset intersects only one PID, then as indicated at block 94, satellite gateway 14 may add the PID in the client PIDset that was not previously present in the cross-system PIDset as a cross-system PIDset. . In alternative embodiments, block 92 may be omitted from method 80 and satellite gateway 14 may advance to block 98 regardless of the number of intersections. Returning to block 96, once the crossover PID has been added to the crossover system PIDset, the satellite gateway 14 is assigned to a multicast group of crossover system PIDsets (which now includes one additional PID from the client PIDset). It can respond to request STBs 22a-22n with an IP address. Also, even if the collision PIDset is empty, the satellite gateway 14 may also respond with a multicast on the collision PIDset for the transponder associated with the client PIDset, so that the STBs 22a-22n intersect the system PIDset. Collision multicasts can be monitored when a later collision with one of the PIDs in it occurs. After the response, when another one of the STBs 22a-22n makes a request for the service, the method may loop to block 84.

Returning to block 92, if the client PIDset intersects the system PIDset at more than one PID, as indicated at block 98, the satellite gateway 14 intersects the client PIDset for each intersecting system PIDset. You can move an intersecting PID from both system PIDsets. The satellite gateway 14 may then add the cross PID to the collision PID set, as indicated at block 100. After generating the collision PIDset, the satellite gateway 14 may add the client PIDset to the system PIDset array, as indicated at block 102, and increment the counter SPTSNum, as indicated at block 104. .

After doing this, the satellite gateway 14 has a multicast group containing a PID (ie, the previous client PIDset minus the PID in the collision PIDset) from the system PIDset array at the array position SPTSNum-1 and the collision PIDset. It may respond to request STBs 22a-22n with a multicast group containing a PID from it. As described above, even if the collision PIDset is empty (ie, SPTSNum is zero), the satellite gateway 14 responds with a multicast group for the collision PIDset associated with the transponder associated with the client PIDset, in the client PIDset. In case of a later collision involving one of the PIDs, the STB can monitor the collision multicast. Finally, as described, the method 80 may cycle to block 84 when the other of the STBs 22a-22n makes a request for service.

While the invention is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in greater detail herein. However, it should be understood that the invention is not intended to be limited to the particular form disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

The present invention is generally available for transmitting video or other digital data over a network, and more particularly, the present invention provides a program identifier (IP) for Internet protocol ("IP") delivery to provide a client with an uninterrupted service. Available to systems for grouping " PID " into multicast groups.

Claims (20)

A method for grouping program identifiers into a multicast group, the method comprising: Initializing a program identifier of the first group, wherein the program identifier of the first group is an array of a series of program identifiers currently being multicast or previously multicast by the satellite service providing device 14; Initializing a program identifier of a; Generating a second group of program identifiers comprising a series of conflicting programs generated for each transponder being received by the satellite service providing device 14; Receiving a request for satellite service from the requester device (22), comprising: receiving a request comprising at least one program identifier; Comparing the requested program identifier with the program identifier of the first group; If the requested program identifier matches one of the program identifiers in the program identifier of the first group, moving the matched program identifier from the program identifier of the first group to the program identifier of the second group, wherein Multicasting of the program identifier is adapted to be shared by the requester device 22 and another device. And grouping program identifiers into multicast groups. The method of claim 1, Transmitting the service associated with the second group of program identifiers to the requester device (22). 3. The method of claim 2, wherein sending the service comprises multicasting the service over an IP distribution network (20). The method of claim 1, Generating a third group of program identifiers including a requested program identifier that does not match one of the program identifiers in the first group of program identifiers; Sending a service associated with the program identifier in the program identifier of the third group to the requester device 22; And grouping program identifiers into multicast groups. 5. A method according to claim 4, comprising storing a third group of program identifiers on the satellite service providing device (14). 2. The method of claim 1, wherein receiving a request for satellite service from the requester device (22) comprises receiving a request for DirecTV satellite programming. 2. The method of claim 1, wherein receiving a request for satellite service from the requester comprises receiving a satellite television request from a set top box. A system for grouping program identifiers into a multicast group, the system comprising: Head-end unit 14, the head-end unit 14, Initialize a first group of program identifiers, which is an array of a series of program identifiers currently being multicasted or previously multicasted by the satellite serving device 14, Generate a second group of program identifiers comprising a series of conflicting programs generated for each transponder being received by the satellite service providing device 14; Receive a request for satellite service from the requester device 22, the request including at least one program identifier, Compare the requested program identifier with the program identifier of the first group, If the requested program identifier matches one of the program identifiers in the program identifier of the first group, move the matched program identifier from the program identifier of the first group to the program identifier of the second group, The multicast of program identifiers of the second group is adapted to be shared by the requestor device (22) and another device. 9. The head-end unit 14 according to claim 8 is: A system for grouping program identifiers into a multicast group, configured to transmit to a requesting device (22) a service associated with the program identifier in a second group of program identifiers. 9. Grouping program identifiers into a multicast group according to claim 8, wherein the head-end unit (14) is configured for transmitting to the second set top box (22) a service associated with the program identifier in the second group of program identifiers. System. 10. The system of claim 8, wherein the head-end unit (14) is configured for multicasting services to a set top box (22) via an IP distribution network (20). 9. The head-end unit 14 according to claim 8 is: Generate a third group of program identifiers including a requested program identifier that does not match one of the program identifiers in the first group of program identifiers, A system for grouping program identifiers into a multicast group, configured to transmit a service associated with a program identifier within a third group of program identifiers. 10. The system of claim 8, wherein the head-end unit is configured to receive a request for DirecTV satellite programming. As the head-end unit: Means for initializing a program identifier of the first group, wherein the program identifier of the first group is an array of a series of program identifiers currently being multicast or previously multicast by the satellite service providing device 14 Means for initializing a program identifier; Means for generating a second group of program identifiers comprising a series of conflicting programs generated for each transponder being received by the satellite service providing device 14; Means for receiving a request for satellite service from the requester device (22), wherein the request comprises at least one program identifier; Means for comparing the requested program identifier with a program identifier of the first group; And Means for moving the matched program identifier from the program identifier of the first group to the program identifier of the second group if the requested program identifier matches one of the program identifiers in the program identifier of the first group; Wherein the multicast of the program identifier of the apparatus comprises means for moving the program identifier adapted to be shared by the requestor device (22) and another device. 15. The head-end unit of claim 14, comprising means for transmitting to a requester device (22) a service associated with a program identifier in a second group of program identifiers. The method of claim 14, Means for transmitting a service comprising multicasting the service over an IP distribution network (20). The method of claim 14, Means for generating a third group of program identifiers including a requested program identifier that does not match one of the program identifiers in the first group of program identifiers; And Means for transmitting to the requester device (22) a service associated with the program identifier in the third group of program identifiers. 15. The head-end unit of claim 14, comprising means for storing a third group of program identifiers on the head-end unit (14). 15. The head-end unit of claim 14, wherein the means for receiving a request for satellite service from the requester device (22) comprises receiving a request for DirecTV satellite programming. 15. The head-end unit of claim 14, wherein the means for receiving a request for satellite service from the requester device (22) comprises a receiver configured to receive the request from the set top box.

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