FIELD OF INVENTION

[001] This invention relates to satellite networks, and more particularly to multicasting content over satellite networks.

BACKGROUND OF INVENTION

[002] In the context of broadcasting, backhaul refers to the uncut program content that is transmitted point to point to a receiving entity where it will be integrated into finished multimedia information. Multimedia services provided in wireless networks consume a substantial amount of expensive backhaul capacity, even if multicasting is used.

Multimedia services are also highly asymmetrical, but for most part backhaul capacity is provided and billed on symmetric or close to symmetric basis as traditional voice communication is symmetrical traffic.

[003] Wireless broadcast network backhaul can be implemented in two different segments, one reserved for voice and two way traffic and another segment for one way broadcast traffic that is reserved for multimedia distribution. The most natural implementation of such systems include C or Ku band satellite distribution to broadcast sites where satellite signal is received and appropriate cache is implemented. A single full or partial transponder satellite broadcast solution can serve in an infinite number of terrestrial broadcast sites.

[004] In a broadcast or multicast solution, multimedia content is delivered to base stations via C band or terrestrial backhaul networks. C band systems require large receiving antennas (2.5 to 3 meter diameter antennas) and further, there is a scarcity of available transponders. Terrestrial backhaul may not be available in all locations, and may be very expensive to provide and support for large availability time.

[005] Ku band requires dishes which range from 60cm to 1 meter, which make them easy to place atop towers or buildings. The issue with Ku band is that it is subject to outage due to rain fade. Therefore, the terrestrial broadcast system would be subject to outages caused by weather. Since these outages are unacceptable, Ku band backhaul systems require a robust implementation.

OBJECT OF INVENTION

[006] The principal object of this invention is to provide an interruption free multicasting of multimedia content via a satellite link. This system has a back up of a low end terrestrial link connected via a suitable means.

STATEMENT OF INVENTION

[007] Accordingly the invention provides a method for transmitting content in a satellite network, the method comprising of a Broadcast Multicast - Service Center (BM-SC) coding the content using a suitable coding scheme; the BM-SC interleaving the coded content; an Uplink station transmitting the coded and interleaved content to at least one base station using Ku band; the base station attempting to recover received content, if errors are present in the coded and interleaved content received at the base station; the base station verifying the received content for any losses in content; the base station requesting the BM-SC to retransmit the lost content, on the base station detecting lost content in the received content; the BM-SC retransmitting the lost content; and the base station inserting the retransmitted lost content into the received content.

[008] Disclosed herein is a satellite network, the satellite network comprising at least one means configured for coding the content using a suitable coding scheme by a Broadcast Multicast - Service Center (BM-SC); interleaving the coded content by the BM-SC; transmitting the coded and interleaved content to at least one base station by an uplink station using Ku band; attempting to recover received content by the base station, if errors are present in the coded and interleaved content received at the base station; verifying the received content by the base station for any losses in content; requesting the BM-SC to retransmit the lost content by the base station, on the base station detecting lost content in the received content; retransmitting the lost content by the BM-SC; and inserting the retransmitted lost content into the received content by the base station.

[009] Also, disclosed herein is a Broadcast Multicast - Service Center (BM-SC) in a satellite network, the BM-SC comprising at least one means configured for coding the content using a suitable coding scheme; interleaving the coded content; receiving a request from a base station for retransmission of lost content; and retransmitting the lost content, on receiving the request.

[010] Embodiments herein also disclose a base station in a satellite network, the base station comprising at least one means configured for attempting to recover coded and interleaved content received by the base station, if errors are present in the coded and interleaved content received by the base station; checking the coded and interleaved content for any losses in content; requesting the BM-SC to retransmit the lost content, if the base station is unable to recover the lost content; and inserting retransmitted lost content into the received content.

[011] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

BRIEF DESCRIPTION OF FIGURES

[012] This invention is illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:

[013] FIG. 1 depicts a satellite communication network, according to embodiments as disclosed herein;

[014] FIG. 2 depicts the Broadcast Multicast - Service Center (BM-SC), according to embodiments as disclosed herein;

[015] FIG. 3 depicts an adaptation module, according to embodiments as disclosed herein;

[016] FIG. 4 is a flowchart illustrating the process, according to embodiments as disclosed herein; and

[017] FIG. 5 is a flowchart illustrating the process, according to embodiments as disclosed herein.

DETAILED DESCRIPTION OF INVENTION

[018] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.

[019] The embodiments herein achieve a method and system for providing an interruption free broadcasting of multimedia content via a satellite link. Referring now to the drawings, and more particularly to FIGS. 1 through 5, where similar reference characters denote corresponding features consistently throughout the figures, there are shown preferred embodiments.

[020] FIG. 1 depicts a satellite communication network, according to embodiments as disclosed herein. The system, as depicted, comprises of a Broadcast Multicast - Service Center (BM-SC) 101, an uplink station 102, a satellite 103 and a base station 104. The BM-SC 101 is connected to the uplinks station 102 using a suitable means. The suitable means may be a wired means or a wireless means. In another embodiment, the BM-SC
101 may be present within the uplink station 102. The uplink station 102 is connected to the base station 104 via the satellite 103. The uplink station 102 may also be connected to the base station 104 via a not a high end terrestrial link, where the terrestrial link may be a suitable communication means such as a wired network, a wireless network or a cellular communication network. The base station 104 further comprises of an adaptation module 105, which processes received data.

[021] The BM-SC 101 receives content to be broadcast/multicast from at least one source. The content may be multimedia content or any other type of content which is IP packetized. The BM-SC 101 processes the content by applying a suitable coding scheme to the content and also interleaves the content using a suitable interleaving algorithm and interval. The coded and interleaved content is sent to the uplink station 102 for transmission to the base station 104. The uplink station 102 sends the content to the base station 104 via the satellite using Ku band. The content may also be sent to more than one base station 104. The satellite receive system at the base station 104 forwards the coded and interleaved content which may contain errors to the adaptation module 105, which then de-interleaves and decodes the same to recover the said broadcast/multicast content. The adaptation module checks the said recovered content for any losses in content. In case of any losses in the received content, the adaptation module 105 requests the uplink station 102 to send the said lost content using the terrestrial network or the satellite link. The request may be sent via the satellite link or the terrestrial network.

[022] FIG. 2 depicts the Broadcast Multicast - Service Center (BM-SC), according to embodiments as disclosed herein. The BM-SC 101 comprises of a forward error correction coding module 201, an interleaving module 202, a timing module 203, a communication processing module 204, a communication interface and a memory 205. The coding module 201 uses a suitable coding scheme on the received content. The content may also be fetched from the memory 205. The coding scheme may be a raptor coding scheme, convolutional coding in conjunction with Reed Solomon Coding scheme or any other suitable coding scheme. The coded content is sent to the interleaving module 202, which interleaves the content with appropriate algorithm and duration. The appropriate algorithm and duration depends on the meteorological conditions of the location of the base station e.g. high rain rate, percentage of rain rate exceeding certain mm/hr and so on; which are known to the BM-SC 101. The coding and interleaving schemes are chosen so as to overcome the propagation effects including rain attenuation and fades in the area where the base station 104 is located. The coded and interleaved content is sent to the communication processing module 204, which performs necessary operations on the content, before sending the content to the uplink station 102 through a communication link.

[023] The BM-SC 101 may receive a request from the base station 103 to retransmit the lost content. The request may be received via the communication interface 206. On receiving the request, the BM-SC 101 may retransmit the lost content using the terrestrial link or the satellite link.

[024] The timing reference 203 provides timing references to the communication processing module 204, which are inserted in the content.

[025] At the uplink station, the processed content from the communication link is recovered and suitable IF modulation is performed on the same before frequency up conversion, RF amplification and up linking to the satellite. In an embodiment herein, the BM-SC 101 is present within the uplink station 102 and may perform the IF modulation function

[026] FIG. 3 depicts an adaptation module, according to embodiments as disclosed herein. The adaptation module 105, as depicted, comprises of a de-interleaving module 301, a decoding module 302, a controller 303, a memory 304 and a communication interface 305. The adaptation module 105, on receiving the coded and interleaved content, sends the content to the de-interleaving module 301. The de-interleaving module 301 de-interleaves the content. The content is then sent to the decoding module 302, which decodes the content back to its original form. The controller 303 verifies the content. If the controller 303 detects that at least a portion of the content has been lost, the controller 303 sends a request to the uplink station 102 to retransmit the content using the communication interface 305. The controller 303, on receiving the retransmitted content r inserts the same into the already received error free content stored in the memory 304. The controller 303 may also store the content in the memory 304. The controller 303 may fetch the content from the memory 304 at a later point in time for further broadcasting/multicasting and uses the timing information present within the content for synchronization.

[027] FIG. 4 is a flowchart illustrating the process, according to embodiments as disclosed herein. The BM-SC 101 receives (401) the content. The BM-SC 101 codes (402) the content using a suitable coding scheme. The coding scheme may be a raptor coding scheme, a convolutional coding scheme in conjunction with Reed Solomon coding or any other suitable coding scheme. The BM-SC 101 then interleaves (403) the coded content. The BM-SC 101 further processes (404) the content, before sending (405) the content to the uplink station 102 and the uplink station 102 transmitting the content. The various actions in method 400 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIG. 4 may be omitted.

[028] FIG. 5 is a flowchart illustrating the process, according to embodiments as disclosed herein. The adaptation module 105 receives (501) the coded and interleaved content and de-interleaves (502) the same.

The adaptation module 105 then decodes (503) the content back to its original form. The adaptation module 105 checks (504) the content for any errors or losses in content. If the adaptation module 105 does not detect any error or losses, it proceeds (506) with the next content, which has been received. If the adaptation module 105 detects any losses in content, the adaptation module 105 requests (505) to retransmit the content using the terrestrial network or a satellite link. The various actions in method 500 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIG. 5 may be omitted.

[029] Embodiments herein disclose the use of Ku band for linking the uplink station and the base station to the satellite merely as an example. Any other fragile or outage prone link may also be used.

[030] Embodiments herein enable maintaining an uninterrupted content stream at each local broadcast location and deliver this uninterrupted stream to the transmission system, thus allowing a Ku band or other fragile or outage prone link to be used for content delivery.

[031] Embodiments herein use local caching to permit use of Ku band satellite transponder capacity for site by site terrestrial broadcast system content distribution.

[032] Embodiments herein use coding for allowing the use of Ku band satellite transponder capacity for site by site terrestrial broadcast/multicast system content distribution and interleaving to enable use of Ku band satellite transponder capacity for site by site terrestrial broadcast/multicast system content distribution.

[033] The embodiments disclosed herein can be implemented through at least one software program running on at least one hardware device and performing network management functions to control the network elements. The network elements shown in Figs. 1, 2 and 3 include blocks which can be at least one of a hardware device, or a combination of hardware device and software module.

[034] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

WE CLAIM :-

1. A method for transmitting content in a satellite network, said method
comprising of

A Broadcast Multicast - Service Center (BM-SC) coding said content using a suitable coding scheme;

Said BM-SC interleaving said coded content;

An Uplink station transmitting said coded and interleaved content to at least one base station using Ku band;

Said base station attempting to recover received content, if errors are present in said coded and interleaved content received at said base station;

Said base station verifying said received content for any losses in content;

Said base station requesting said BM-SC to retransmit said lost content, on said base station detecting lost content in said received content;

Said BM-SC retransmitting said lost content; and

Said base station inserting said retransmitted lost content into said received content.

2. The method, as claimed in claim 1, wherein said coding scheme is at
least one of

A raptor coding scheme; or

A Convolutional coding scheme in conjunction with Reed Solomon coding.

3. The method, as claimed in claim 1, wherein said method further comprises of said base station storing said content.

4. The method, as claimed in claim 1, wherein said BM-SC retransmits said lost content using at least one of

said satellite network; or a terrestrial network.

5. A satellite network, said satellite network comprising at least one
means configured for

coding said content using a suitable coding scheme by a Broadcast Multicast - Service Center (BM-SC);

interleaving said coded content by said BM-SC;

transmitting said coded and interleaved content to at least one base station by an uplink station using Ku band;

attempting to recover received content by said base station, if errors are present in said coded and interleaved content received at said base station;

verifying said received content by said base station for any losses in content;

requesting said BM-SC to retransmit said lost content by said base station, on said base station detecting lost content in said received content;

retransmitting said lost content by said BM-SC; and

inserting said retransmitted lost content into said received content by said base station.

6. The satellite network, as claimed in claim 5, wherein said satellite network is configured for using said coding scheme, wherein said coding scheme is at least one of

A raptor coding scheme; or

A Convolutional coding scheme in conjunction with Reed Solomon coding

7. The satellite network, as claimed in claim 5, wherein said satellite network is configured for enabling said base station to store said content.

8. The satellite network, as claimed in claim 5, wherein said satellite network is configured for said BM-SC to retransmit said lost content using at least one of said satellite network; or a terrestrial network.

9. A Broadcast Multicast - Service Center (BM-SC) in a satellite network, said BM-SC comprising at least one means configured for

coding said content using a suitable coding scheme;

interleaving said coded content;

receiving request from a base station for retransmission of lost content; and

retransmitting said lost content, on receiving said request.

10. The BM-SC, as claimed in claim 9, wherein said BM-SC is configured for using said coding scheme, wherein said coding scheme is at least one of

A raptor coding scheme; or

A convolutional coding scheme in conjunction with Reed Solomon coding

11. The BM-SC, as claimed in claim 9, wherein said BM-SC is configured to retransmit said lost content using at least one of said satellite network; or a terrestrial network.

12. A base station in a satellite network, said base station comprising at least one means configured for attempting to recover coded and interleaved content received by said base station, if errors are present in said coded and interleaved content received by said base station;

checking said coded and interleaved content for any losses in content;

requesting said BM-SC to retransmit said lost content, if said base station is unable to recover said lost content; and

inserting retransmitted lost content into said received content.

13. The base station, as claimed in claim 12, wherein said base station is configured for storing said content.