Abstract:
A method for multicasting Internet Protocol (IP) streaming data to a mobile platform passenger is provided. The method includes receiving data content at a base station network from a content provider. The received data is formatted at the base station into an IP multicast data stream and communicated to a mobile platform communications system onboard a mobile platform. The mobile platform communications system includes a local area network (LAN) used to distribute the IP multicast data stream to at least one mobile platform client interface. The data content of the IP multicast data stream is then displayed on the mobile platform client interface for viewing by a mobile platform passenger. Additionally, the method includes applying forward error correction (FEC) to the IP multicast data stream to correct for data losses, prior to distributing the IP multicast data stream to the mobile platform client interface. The method further includes decoding the FEC encoded IP multicast data stream so that the corrected data content can be interpreted and displayed on the mobile platform client interface.

Description:
FIELD OF INVENTION  
       [0001]     The invention relates generally to the communication of streaming data to a mobile platform and more particularly to correcting data loss errors that occur during wireless transmission of Internet Protocol (IP) multicast data streams.  
       BACKGROUND OF THE INVENTION  
       [0002]     The transmission of reliable multicast data over wireless channels is typically unreliable due to data losses during the transmission. Conversely, unicast wireless transmissions, e.g. TCP transactions, for such things as ‘surfing’ the Internet and e-mail transmissions are generally more reliable because unicast transmissions are acknowledged transmissions. That is, when a packet of data is sent, via unicast transmissions, an acknowledgement is returned indicated whether or not the data packet was received. Thus, if a data packet is not received, the acknowledgement indicates so and the data packet is resent to correct the error. However, multicast data transmissions do not include an acknowledgement and have no embedded correction mechanism. Thus, if any bit errors occur in a packet, the entire packet can be corrupted and lost, the sender will be unaware of the lost data, and the target receives streaming data that is missing data. For example, packets in a multicast audio or video stream, are quite large, e.g. 1500 bytes, thus, losing one packet can result in ‘choppy’ streaming, ‘freeze frames’ or gaps in the audio or video.  
         [0003]     The occurrence of data loss can be amplified when the wireless multicast streaming data is transmitted within a closed environment such as a mobile platform, e.g. an aircraft, train, bus or ship. The characteristics of wireless multicast transmissions within a mobile platform are such that the electromagnetic waves can propagate through the interior of the mobile platform and cause destructive interference with each other. Even further losses can occur within a closed environment due to hardware characteristic of the devices receiving the multicast signals, e.g. laptop computers. The wireless cards or antennas of the receiving devices can be very inefficient and cause considerable packet loss. Additionally, typically the error correction software accompanying such devices provide only a low level, inefficient correction scheme.  
         [0004]     Therefore, it would be desirable to wirelessly multicast streaming data, e.g. live news, sports, etc., within a closed environment, such as a mobile platform, efficiently and with error correction to correct for data loss.  
       BRIEF SUMMARY OF THE INVENTION  
       [0005]     In a preferred embodiment of the present invention, a method for multicasting Internet Protocol (IP) streaming data to a mobile platform passenger is provided. The method includes receiving data content at a base station network from a content provider. The received data is formatted at the base station into an IP multicast data stream and communicated to a mobile platform communications system onboard a mobile platform. The mobile platform communications system includes a local area network (LAN) used to distribute the IP multicast data stream to at least one mobile platform client interface, e.g. a laptop computer. The data content of the IP multicast data stream is then displayed on the mobile platform client interface for viewing by a mobile platform passenger or crew member. Additionally, the method includes applying forward error correction (FEC) to the IP multicast data stream to correct for data losses, prior to distributing the IP multicast data stream to the mobile platform client interface. The method further includes decoding the FEC encoded IP multicast data stream so that the corrected data content can be interpreted and displayed on the mobile platform client interface.  
         [0006]     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiments of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. Furthermore, the features, functions, and advantages of the present invention can be achieved independently in various embodiments of the present inventions or may be combined in yet other embodiments. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]     The present invention will become more fully understood from the detailed description and accompanying drawings, wherein;  
         [0008]      FIG. 1  is a general schematic illustrating a Internet protocol multicast communication system that implements forward error correction, in accordance with the present invention;  
         [0009]      FIG. 2  is a general schematic illustrating an onboard communications system shown in  FIG. 1 ;  
         [0010]      FIG. 3  is a general schematic illustrating a base station shown in  FIG. 1 ;  
         [0011]      FIG. 4  is a general schematic illustrating one preferred alternate embodiment of the onboard communications system shown in  FIG. 2 ;  
         [0012]      FIG. 5  is a general schematic illustrating one preferred alternate embodiment of the base station shown in  FIG. 3 ; and  
         [0013]      FIG. 6  is a flow chart illustrating a method of operation of the Internet protocol multicast communication system, shown in  FIG. 1 .  
     
    
       [0014]     Corresponding reference numerals indicate corresponding parts throughout the several views of drawings.  
       DETAILED DESCRIPTION OF THE INVENTION  
       [0015]      FIG. 1  is a general schematic illustrating an Internet Protocol multicast communication system (IPMCS)  10  that implements forward error correction (FEC), in accordance with preferred embodiments of the present invention. The IPMCS  10  includes at least one base station  14 , at least one satellite gateway  18 , at least one satellite  22  and a mobile platform communications system  26 , e.g. a local area network (LAN), onboard a mobile platform  30 . In a preferred embodiment, the mobile platform communications system  26  is a wireless LAN. Although the mobile platform  30  is illustrated in  FIG. 1  as an aircraft, it should be understood that the mobile platform  30  could be any mobile platform that includes an onboard communication system  26 , for example, land vehicles such as a bus, a train or an automobile, and maritime vehicles, such as a cruise ship.  
         [0016]     Generally, the base station  14  receives streaming data from a content provider that can be any multimedia source adapted to provide information and/or entertainment data. For example, the content provider can be any multimedia source that provides such things as news, sports, music, movies, stock market information, Internet access and other types of information or entertainment data. The base station  14  formats the data from the content provider into an internet protocol (IP) multicast data stream that is communicated to the satellite gateway  18 .  
         [0017]     A multicast data stream is a non-acknowledgement transaction, as opposed to a unicast data stream which sends an acknowledgement back indicating whether an end user device received all the data intact. Thus, if data bits or data packets are not received by the end user device, the device will not know there is missing or lost data and improperly or incompletely interpret and/or display the data content. Generally, multicast is more efficient than unicast in distributing the same data to multiple recipients. Unicast send data as many times as there are recipients, whereas multicast will distribute the data to all recipients in a single transmission. Wireless communications such as communications to a mobile platform is typically restricted to low bandwidth, for example 5 to 10 megabits that would only support a few, e.g. six or seven, end user devices using unicast scheme. Thus, communications to and/or within mobile platforms generally incorporate multicast to efficiently transmit data to multiple recipients.  
         [0018]     The IP multicast data stream can be communicated between the base station  14  and the satellite gateway  18  using any suitable wired or wireless communication means. The IP multicast data stream is communicated from the satellite gateway  18  to the satellite  22  and then to the onboard communications system  26 , particularly to an antenna  34  included in the onboard communications system  26 . The antenna  34  is communicatively connected to a receive/distribute subsystem  38  of the onboard communications system  26 .  
         [0019]     Referring to  FIG. 2 , the onboard communications system  26  includes a communications receiving component  42  that receives the IP multicast data stream from the antenna  34 . The communications receiving component  42  then communicates the IP multicast data stream to a distribution component  46 , which can be any suitable network distribution device such as a server  46 A, a network hub  46 B or a wireless local area network (WLAN)  46 C. The distribution component  46  distributes at least the content of the IP multicast data stream to one or more mobile platform client interfaces  50 , as described in further detail below. In one preferred embodiment the communication between the distribution component  46  and the client interface  50  is wireless communication. The client interface  50  can be any computer based device suitable for receiving at least the data content from the distribution component  46  and displaying the data content to be viewed by a passenger or crew member of the mobile platform. For example, the client interface  50  can be a computer based input/output device install onboard the mobile platform in crew quarters accessible by crew members or in a passenger cabin accessible by passengers of the mobile platform. Or, the client interface  50  can be a portable laptop computer, personal data assistant (PDA), cell phone or other portable computer based communication device carried onto the mobile platform or distributed onboard the mobile platform and communicatively connected to the distribution device  46 .  
         [0020]     Referring now to  FIG. 3 , the base station  14  includes at least one IP encoder  54  that receives the streaming data from the content provider and formats, i.e. encodes, the data into IP data. As described above, the content provider can be any multimedia source adapted to provide information and/or entertainment data. For example, the content provider can be a satellite gateway, a terrestrial communications system, the Internet, stored media or a direct input/output device such as a video camera. The IP encoder  54  formats the data from the content provider into IP data and generates an IP multicast data stream that is communicated to at least one base station server  58 . The base station server  58  communicates the IP multicast data stream to a communication transmission component  62  that, in turn, communicates the IP multicast data stream to the satellite gateway  18 .  
         [0021]     Referring now to  FIGS. 3 and 4 , in one preferred embodiment of the present invention, the mobile platform receive/distribute subsystem  38  includes a FEC processing component  70 . The FEC processing component  70  is configured to encode the IP multicast data stream received from mobile platform communications receiving component  42  with FEC. The FEC processing component  70  encodes the IP multicast data stream using FEC to correct for lost data bits or packets. Generally, FEC constructs mathematical formulas used to recover lost data and may add information to the original data stream, e.g. protection packets, and/or remap the original data stream to a new data stream to increase the likelihood of reconstructing the original data stream. The FEC processing component  70  can be either a software component or an independent device of the receive/distribute subsystem  38  and can implement any suitable form of FEC known in the art that can be configured relative to the mobile platform in which it is implemented, e.g. Reed-Solomon type coding.  
         [0022]     In one implementation of this embodiment, the FEC processing component  70  encodes the IP multicast data stream and communicates the FEC encoded IP multicast data stream to the mobile platform server  46 A, which in turn, communicates the FEC encoded IP multicast data stream to the client interface  50 , via either wired or wireless connections. The client interface  50  includes IP and FEC decoding software adapted to decode the IP format and the FEC of the FEC encoded IP multicast data stream so that the decoded data content can be displayed and viewed by either a passenger or crew member.  
         [0023]     Still referring to  FIGS. 3 and 4 , in another preferred embodiment, the FEC processing component  70  encodes the IP multicast data stream and communicates the FEC encoded IP multicast data stream to the mobile platform hub  46 B, via wired or wireless connections. The mobile platform hub  46 B communicates the FEC encoded IP multicast data stream to the client interface  50 , via either wired or wireless connections. The client interface utilizes IP and FEC decoding software to decode the IP format and the FEC of the FEC encoded IP multicast data stream and display the decoded data content to be viewed by either a passenger or crew member.  
         [0024]     Still referring to  FIGS. 3 and 4 , in yet another preferred embodiment, the FEC processing component  70  encodes the IP multicast data stream and communicates the FEC encoded IP multicast data stream to the mobile platform WLAN  46 C, via wired or wireless connections. The mobile platform WLAN  46 C wirelessly communicates the FEC encoded IP multicast data stream to the client interface  50 . The client interface utilizes IP and FEC decoding software to decode the IP format and the FEC of the FEC encoded IP multicast data stream and display the decoded data content to be viewed by either a passenger or crew member.  
         [0025]     Referring to  FIG. 5 , in one embodiment the base station  14  includes a forward error correction (FEC) encoder  74  that receives the IP multicast data stream from the base station server  58 . The base station FEC encoder  74  encodes the IP multicast data stream using FEC to correct for lost data bits or packets. Generally, FEC constructs mathematical formulas used to recover lost data and may add information to the original data stream, e.g. protection packets, and/or remap the original data stream to a new data stream to increase the likelihood of reconstructing the original data stream. The FEC encoder  74  can be either a software component or an independent device of the base station  14  and can implement any suitable form of FEC known in the art that can be configured relative to the mobile platform in which it is implemented, e.g. Reed-Solomon FEC.  
         [0026]     The FEC encoder  74  then communicates the FEC encoded IP multicast data stream to the communications transmission component  62  that, in turn communicates the FEC encoded IP multicast data stream to the satellite gateway  18  and subsequently to the mobile platform communications receiving component  42 , via the satellite  22  and the mobile platform antenna  34 .  
         [0027]     Referring to  FIGS. 2 and 5 , in one preferred embodiment the communications receiving component  42  communicates the FEC encoded IP multicast data stream, via either wired or wireless connections, to the mobile platform server  46 A. In one implementation of this embodiment, the mobile platform server  46 A communicates the FEC encoded IP multicast data stream to the client interface  50 , via either wired or wireless connections. The client interface  50  includes IP and FEC decoding software adapted to decode the IP format and the FEC of the FEC encoded IP multicast data stream so that the decoded data content can be displayed and viewed by either a passenger or crew member.  
         [0028]     Still referring to  FIGS. 2 and 5 , in another preferred embodiment the communications receiving component  42  communicates the FEC encoded IP multicast data stream, via either wired or wireless connections, to the mobile platform hub  46 B. The mobile platform hub  46 B communicates the FEC encoded IP multicast data stream, via either wired or wireless connections, to the client interface  50  that includes IP and FEC decoding software. Thus, the client interface  50  decodes the IP format and the FEC of the FEC encoded IP multicast data stream and displays the decoded data content to be viewed by either a passenger or crew member.  
         [0029]     Still further referring to  FIGS. 2 and 5 , in yet another preferred embodiment the communications receiving component  42  communicates the FEC encoded IP multicast data stream, via either wired or wireless connections, to the mobile platform WLAN  46 C. The mobile platform WLAN  46 C wirelessly communicates the FEC encoded IP multicast data stream to the client interface  50  that includes IP and FEC decoding software. Thus, the client interface  50  decodes the IP format and the FEC of the FEC encoded IP multicast data stream and displays the decoded data content to be viewed by either a passenger or crew member.  
         [0030]     Referring now to  FIGS. 4 and 5 , in one preferred personification of the present invention, the FEC processing component  70  is configured to FEC decode the FEC encoded IP multicast data stream, and/or the FEC processing component  70  can be configured to FEC decode and then re-encode the IP multicast data stream with FEC. Thus, in one embodiment, the FEC processing component  70  receives the FEC encoded IP multicast data stream from the mobile platform communications receiving component  42  and communicates with the mobile platform server  46 A, via wired or wireless connections. In one implementation of this embodiment the FEC processing unit decodes the FEC of the FEC encoded IP multicast data stream and communicates the IP multicast data stream to the mobile platform server  46 A. The mobile platform server  46 A decodes the IP multicast data stream and communicates a data stream in a format that can be understood by the client interface  50 , via either wired or wireless connections. The client interface  50  then displays the data content of the multicast data stream to be viewed by either a passenger or crew member.  
         [0031]     In another implementation of this embodiment, the FEC processing component  70  decodes the FEC of the FEC encoded IP multicast data stream and communicates the IP multicast data stream to the mobile platform server  46 A, which in turn, communicates the IP multicast data stream to the client interface  50 , via either wired or wireless connections. The client interface  50  includes IP decoding software adapted to decode the IP of the IP multicast data stream so that the decoded data content can be displayed and viewed by either a passenger or crew member.  
         [0032]     In yet another implementation of this embodiment, the FEC processing component  70  decodes the FEC, then re-encodes the IP multicast data stream with FEC and communicates the FEC re-encoded IP multicast data stream, via wired or wireless connections, to the mobile platform server  46 A. The mobile platform server  46 A communicates the FEC re-encoded IP multicast data stream to the client interface  50 , via either wired or wireless connections. The client interface  50  includes IP and FEC decoding software adapted to decode the IP format and the FEC of the FEC re-encoded IP multicast data stream so that the decoded data content can be displayed and viewed by either a passenger or crew member.  
         [0033]     In still yet another implementation of this embodiment, the FEC processing component  70  adds a second layer of FEC to the existing FEC encoded IP multicast stream, creating a cumulative FEC protected stream. The FEC processing component  70  then communicates the cumulative FEC encoded IP multicast data stream, via wired or wireless connections, to the mobile platform server  46 A. The mobile platform server  46 A communicates the FEC re-encoded IP multicast data stream to the client interface  50 , via either wired or wireless connections. The client interface  50  includes IP and FEC decoding software adapted to decode the IP format and the FEC of the cumulative FEC encoded IP multicast data stream so that the decoded data content can be displayed and viewed by either a passenger or crew member.  
         [0034]     Still referring to  FIGS. 4 and 5 , in another preferred embodiment, the FEC processing component  70  receives the FEC encoded IP multicast data stream from the mobile platform communications receiving component  42  and communicates with the mobile platform hub  46 B, via wired or wireless connections. In one implementation of the present embodiment, the FEC processing unit decodes the FEC of the FEC encoded IP multicast data stream and communicates the IP multicast data stream to the mobile platform hub  46 B. The mobile platform hub  46 B communicates the IP multicast data stream to the client interface  50 , via either wired or wireless connections. The client interface  50  includes IP decoding software adapted to decode the IP of the IP multicast data stream so that the decoded data content can be displayed and viewed by either a passenger or crew member.  
         [0035]     In another implementation of the this embodiment, the FEC processing component  70 , decodes the FEC, then re-encodes the IP multicast data stream with FEC and communicates a FEC re-encoded IP multicast data stream, via wired or wireless connections, to the mobile platform hub  46 B. The mobile platform hub  46 B communicates the FEC re-encoded IP multicast data stream, via either wired or wireless connections, to the client interface  50  that includes IP and FEC decoding software. Thus, the client interface  50  decodes the IP format and the FEC of the FEC re-encoded IP multicast data stream and displays the decoded data content to be viewed by either a passenger or crew member.  
         [0036]     In yet another implementation of this embodiment, the FEC processing component  70  adds a second layer of FEC to the existing FEC encoded IP multicast stream, creating a cumulative FEC protected stream. The FEC processing component  70  then communicates the cumulative FEC encoded IP multicast data stream, via wired or wireless connections, to the mobile platform hub  46 B. The mobile platform hub  46 B communicates the FEC re-encoded IP multicast data stream to the client interface  50 , via either wired or wireless connections. The client interface  50  includes IP and FEC decoding software adapted to decode the IP format and the FEC of the cumulative FEC encoded IP multicast data stream so that the decoded data content can be displayed and viewed by either a passenger or crew member.  
         [0037]     Still referring to  FIGS. 4 and 5 , in yet another preferred embodiment, the FEC processing component  70  receives the FEC encoded IP multicast data stream from the mobile platform communications receiving component  42  and communicates with the mobile platform WLAN  46 C, via wired or wireless connections. In one implementation of the present embodiment, the FEC processing unit decodes the FEC of the FEC encoded IP multicast data stream and communicates the IP multicast data stream to the mobile platform WLAN  46 C. The mobile platform WLAN  46 C wirelessly communicates the IP multicast data stream to the client interface  50 . The client interface  50  includes IP decoding software adapted to decode the IP of the IP multicast data stream so that the decoded data content can be displayed and viewed by either a passenger or crew member.  
         [0038]     In another implementation of the this embodiment, the FEC processing component  70 , decodes the FEC, then re-encodes the IP multicast data stream with FEC and communicates a FEC re-encoded IP multicast data stream, via wired or wireless connections, to the mobile platform WLAN  46 C. The mobile platform WLAN  46 C wirelessly communicates the FEC re-encoded IP multicast data stream to the client interface  50  that includes IP and FEC decoding software. Thus, the client interface  50  decodes the IP format and the FEC of the FEC re-encoded IP multicast data stream and displays the decoded data content to be viewed by either a passenger or crew member.  
         [0039]     In yet another implementation of this embodiment, the FEC processing component  70  adds a second layer of FEC to the existing FEC encoded IP multicast stream, creating a cumulative FEC protected stream. The FEC processing component  70  then communicates the cumulative FEC encoded IP multicast data stream, via wired or wireless connections, to the mobile platform WLAN  46 C. The mobile platform WLAN  46 C wirelessly communicates the FEC re-encoded IP multicast data stream to the client interface  50  that includes IP and FEC decoding software adapted to decode the IP format and the FEC of the cumulative FEC encoded IP multicast data stream so that the decoded data content can be displayed and viewed by either a passenger or crew member.  
         [0040]      FIG. 6  is a flow chart  100  illustrating a method of operation of the IPMCS  10 , shown in  FIG. 1 . The base station  14  receives streaming data from a content provider that can be any multimedia source adapted to provide information and/or entertainment data, as illustrate at  102 . The base station  14  formats the data from the content provider into an IP multicast data stream, as indicated at  104 . The IP multicast data stream can be communicated to the satellite gateway  18  or be encoded with FEC, via the base station FEC encoder  74  and then communicated to the satellite gateway  18 , as indicated at  106 . The IP multicast data stream or the FEC encoded IP multicast data stream is then communicated to the mobile platform communications system  26 , via satellite  22 , as indicated at  108  and  110 . If the mobile platform communications system  26  receives an FEC encoded IP multicast data stream, the FEC encoded IP multicast data stream can optionally be FEC decoded utilizing the FEC processing component  70 , as indicated at  112 . The decoded IP multicast data stream is distributed to the client interface  50  and displayed, in accordance with the various embodiments described above, as indicated at  114  and  116 . Alternatively, the FEC encoded IP multicast data stream is not FEC decoded by FEC processing module  38 , but is distributed to the client interface  50 . The client interface decodes the FEC encoded IP multicast data stream and displays the data content, in accordance with the various embodiments described above, as indicated at  118  and  120 .  
         [0041]     If the mobile platform communications system  26  receives an IP multicast data stream that has not been encoded with FEC, the IP multicast data stream is encoded with FEC utilizing the FEC processing component  70 , as indicated at  122 . Alternatively, if the mobile platform communications system  26  receives an FEC encoded IP multicast data stream and the FEC encoded IP multicast data stream is FEC decoded at  112 , the decoded IP multicast data stream can be re-encoded with FEC utilizing the FEC processing component  70 , as also indicated at  122 . If the FEC encoded IP multicast data stream is not FEC decoded at  112 , the FEC processing component  70  can apply further FEC encoding to the FEC encoded IP multicast data stream to create a cumulative FEC encoded IP multicast data stream. The FEC encoded, cumulative encoded, or re-encoded IP multicast data stream is distributed to the client interface  50 , where the client interface decodes the FEC encoded IP multicast data stream and displays the data content, in accordance with the various embodiments described above, as indicated at  124  and  126 .  
         [0042]     While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.