DE112008000052T5 - Apparatus and method for transmitting a broadcast service and apparatus and method for receiving a broadcast service for effective access to a broadcast service - Google Patents

Abstract

Apparatus for transmitting a broadcast service, comprising:
A broadcast data packetizing unit that packetizes at least one type of broadcasting data to produce at least one broadcasting data packet;
a transmission packet generation unit that generates at least one transmission packet for transmission of the at least one broadcast data packet;
a transmission frame generation unit that generates a transmission frame having a predetermined size for transmitting the at least one broadcasting service formed with the at least one transmission packet; and
a transmission unit that transmits the transmission frame,
wherein the transmission frame generating unit generates the transmission frame such that service access information for access to the at least one broadcast service transmitted via the transmission frame is included in the transmission frame.

Description

Technical area

The The present invention relates to an apparatus and a method to provide a broadcasting service consisting of various Data types is formed, and more specifically a device and a Method for transmitting a broadcast service and an apparatus and a method for receiving a broadcast service, for a quick and direct access to the desired services to enable.

Technical background

At the digital broadcasts are when multiple service channel signals are multiplexed and transmitted over a single transmission path First, the service channel signals are compressed one by one and in Packets are implemented, and then the packets are put into a transmission stream multiplexed. Packages that belong to a single channel will assigned an identical packet identifier (PID), so packages can be differentiated from packages, the other channels correspond. If packages are different have specific IDs that match the types of channels are assigned, transmitted in the form of a transmission data stream So, a recipient chooses only one package desired channel from the transmission data stream by looking at the IDs of the packages in the desired Channel and demultiplexes the selected packets.

1 FIG. 10 is a flowchart illustrating a prior art method of processing a transmission data stream generated using packet identifiers (PIDs).

A prior art receiver processes a transmission data stream corresponding to that in FIG 1 shown method. In operation S110, a coded transmission data stream containing packets is received. In operation S120, the Reed-Solomon (RS) decoding of the packets of the transmission data stream is performed. In operation S130, the packets of the transmission data stream are filtered according to the PIDs. In operation S140, the packets of the transmission data stream are unpacked in each layer, namely a transport layer, a packetization layer, and a data stream layer. In operation S150, data obtained by unpacking is decoded.

at According to the prior art method, the packets of the transmission data stream by using the PIDs be clearly distinguished from each other. The packets of the transmission data stream however, they must have PIDs, and the receiver after In the prior art, the RS decoding must perform each of the packets of the transmission data stream and perform the filtering by checking the PIDs individually.

2 shows a prior art transmission data stream generated using PIDs. Regarding 2 For example, a transmission data stream packet carrying audio / video (A / V) data, a transmission data stream packet transmitting Internet Protocol (IP) data, and a transmission data stream packet containing object data transmits over a single channel. When the prior art transmission data stream is processed, even if users want to receive only one A / V service, all the transmission / data stream packets of the router / RS decoding and filtering must be subjected to individual checking of the PIDs. Therefore, when the prior art receiver processes data, time and space resources are wasted.

Disclosure of the invention

Technical solution

The The present invention provides an apparatus and method for transmitting a broadcast service and a device and a method for receiving a broadcast service to a efficient data processing through a fast and direct To provide access to the requested services.

Beneficial effects

According to the present invention is in contrast to a method of Providing a service by filtering using packages built of packet identifiers (PIDs), providing direct access to any service component included in a service is possible.

additionally For this purpose, according to the present invention, a Operation of executing RS decoding of all RS coded transmission packets and checking all PIDs of the transmission packets not needed when service components selected become a service. Thus, the waste of system resources by accessing unnecessary transmission packets be prevented.

Further, according to the present invention, when the location of an LMT and an LIT in a transmission frame is fixed, it can be referred to services Service components are accessed quickly.

Further can according to the present invention by recording of information about the next LMT in the current LMT accessed services and service components faster even if the location of a LMT and a LIT in a transmission frame is variable.

Further can according to the present invention by recording of information about the number of LMTs that are identical Version, in a current LMT using the current LMT the previous LMT can be restored, even if in the current one LMT an error is generated.

About that In addition, according to the present invention, a Error package can be detected without it being necessary to Error flag to use by the header information of the error packet will be changed.

Description of the drawings

The above and other features and advantages of the present invention The invention will become clearer by example embodiments thereof described in detail with reference to the accompanying drawings become, in which:

1 Fig. 10 is a flowchart illustrating a prior art method of processing a transmission data stream generated using packet identifiers (PIDs);

2 shows a prior art transmission data stream generated using PIDs;

3 shows a structure of a transmission data stream according to an embodiment of the present invention;

4 the structure of in 3 shown transmission data stream according to an embodiment of the present invention in more detail;

5A and 5B show a structure of a Location Map Table (LMT) field according to an embodiment of the present invention;

5C shows a structure of an LMT field according to another embodiment of the present invention;

6A shows a structure of a Link Information Table (LIT) field according to an embodiment of the present invention;

6B shows a structure of a LIT array according to another embodiment of the present invention;

7A Fig. 10 is a flowchart showing a method of evaluating an LMT field and a LIT field according to an embodiment of the present invention;

7B Fig. 10 is a flowchart showing a method of evaluating an LMT field and a LIT field according to another embodiment of the present invention;

8th Fig. 10 is a block diagram showing a structure of a broadcasting service transmitting apparatus according to an embodiment of the present invention;

9 Fig. 10 is a flowchart showing a method of transmitting a broadcast service according to an embodiment of the present invention;

10 Fig. 10 is a block diagram showing a structure of a broadcasting service receiving apparatus according to an embodiment of the present invention; and

11 Fig. 10 is a flowchart showing a method of receiving a broadcast service according to an embodiment of the present invention.

Best application

According to one aspect of the present invention, there is provided an apparatus for transmitting a broadcast service, comprising: a broadcast data phrasing unit that packages at least one type of broadcast data to generate at least one broadcast data packet; a transmission packet generation unit that generates at least one transmission packet to transmit the at least one broadcast data packet; a transmission frame generating unit that generates a transmission frame having a predetermined size so as to transmit at least one broadcasting service constructed with the at least one transmission packet; and a transmission unit transmitting the transmission frame, the transmission frame generation unit generating the transmission frame so that service access information for accessing the at least one broadcast service transmitted through the transmission frame carry is included in the transmission frame.

The Service access information may be in a before defined area of the transmission frame.

The Service access information can be location information about the next service access information.

The transmission frame may include at least one virtual data channel corresponding to a distinction is made between the data types. Each of the at least one virtual Data channels may include at least one sub-data channel, comprising at least one transmission packet.

The Service access information can be a site plan table (Location Map Table, LMT), which contains information which show a physical location of sub data channels, The service components correspond to the at least one broadcast service which is contained in the transmission frame, and a link information table (Linkage Information Table, LIT), the information about the configuration at least a broadcast service included in the transmission frame contains, include.

The LMT may have type information that indicates types of data being over transmitted to the transmission frame, version information, showing the version of the LMT, sub data channel number information, which is the number of sub-data channels, which is of each data type correspond, and channel pointer information representing the locations of the sub-data channels show, included.

The LMT may also provide at least part of information about identical version LMT numbers indicating the number of LMTs which have the same version as the LMT, LMT pointer information, showing a location of a next LMT, information about the number of extra data representing the number of parts additional data associated with the at least one broadcast service are connected, display, and pointer information additional data showing the location of the additional Show data include.

The LIT can service number information, which is the number of broadcast services which are transmitted via the transmission frame be version information that indicates the version of the LIT and service information, which is a configuration of the broadcast services show, include.

The Service information may include LMT index numbers which are associated with the channel pointer information indicating the location of the Displays sub-data channels.

The transmission unit can create and send an ATSC frame into which at least one inserted above transmission frame is.

According to one Another aspect of the present invention is a method of transmission a broadcast service provided the following operations includes: packetizing at least one type of broadcast data to to generate at least one broadcast data packet; Generate at least a transmission packet for transmission of the at least one broadcast data packet; Generating a transmission frame, which has a predetermined size, at least to broadcast a broadcasting service associated with the at least a transmission packet is set up; and transmitting the transmission frame, wherein the transmission frame is generated to be Service access information for access to the at least one Broadcast service transmitted over the transmission frame contains.

According to one Another aspect of the present invention is a device for receiving a broadcast service, comprising: A receiving unit receiving a transmission frame, which has a predetermined size; one unity for processing the transmission frame sent by the transmission frame Service access information for access to at least one broadcast service acquires and also from the transmission frame at least one transmission packet for transmitting at least one broadcast data packet acquires using the service access information; one unity for processing the transmission packet containing the at least a transmission packet is processed to that at least a broadcast data packet from the at least one transmission packet to acquire; and a unit for processing the broadcast data, which processes the at least one broadcast data packet.

According to another aspect of the present invention, there is provided a method of receiving a broadcast service, comprising: receiving a transmission frame having a predetermined size; from the transmission frame acquiring service access information for access to at least one broadcast service and also from the transmission frame acquiring at least one transmission packet for transmission at least one broadcast data packet using the service access information; Processing the at least one transmission packet to obtain at least one broadcast data packet from the at least one transmission packet; and processing the at least one broadcast data packet.

Application of the invention

This patent application claims the benefit of US Provisional Patent Application No. 60 / 917,776, filed May 14, 2007, and US Provisional Patent Application No. 60 / 974,321, filed September 21, 2007, U.S. Patent and Trademark Office, and utility from the Korean Patent Application No. 10-2007-0077165 , filed on 31 July 2007 and the Korean Patent Application No. 10-2007-00124371 filed on 03 December 2007 with the Korean Intellectual Property Office, the disclosures of which are hereby incorporated by reference in their entirety.

The The present invention will now be described in greater detail with reference to FIG to the accompanying drawings, in which exemplary Embodiments of the invention are shown.

The present invention is used in deterministic environments, in which broadcasting services are provided by the one constant size, that is one fixed size, have, in regular Time intervals are sent. In the description will be Frame of constant size as a transmission frame designated.

3 shows a structure of a transmission frame 300 according to an embodiment of the present invention.

Regarding 3 contains the transmission frame 300 According to the current embodiment of the present invention, a service information area 310 and a data area 320 , As in 3 shown, the transmission frame 300 according to the current embodiment of the present invention in a transmission frame of a broadcasting system, which differs from a broadcasting system for the transmission frame 300 is distinguished, inserted and transmitted as part thereof, for example as part of an ATSC frame of an ATSC broadcasting system. Alternatively, the transmission frame 300 or to a broadcast stream of a broadcast system other than a broadcast system for the broadcast frame 300 differs to be mapped in a one-to-one correspondence to be transmitted.

The data area 320 of the transmission frame is divided into virtual data channels, which are distinguished according to the data type. The virtual data channels indicate channels into which channels for transmitting a data stream are physically classified according to the data type. Each of the virtual data channels can be divided into independent sub-data channels. Each of the sub-data channels consists of at least one transmission packet, which is the smallest unit of a data packet packetized in a transport layer.

The service information area 310 includes service access information for accessing data forming a broadcast service, the data being transmitted over the transmission frame 300 be transmitted. The service access information may be implemented to be periodically arranged in a predetermined area of a frame, as in FIG 3 shown. In addition, the current service access information may include information about the location of the next service access information to control a cycle in which service access information is inserted into a frame or to change a location in the frame is inserted at the service access information.

4 shows the structure of the transmission frame 300 according to an embodiment of the present invention in more detail. 4 shows the structure of a transmission frame 400 according to an embodiment of the present invention. Regarding 4 each of the virtual data channels of the in 3 shown data area 320 divided into sub-data channels, and the sub-data channels form services. Regarding 4 includes the transmission frame 400 according to the current version, a signaling packet 410 (or a virtual signaling data channel), a real-time virtual media data channel 420 , a virtual IP data channel 430 and a virtual object data channel 440 ,

Each of the virtual data channels in 4 is divided into sub-data channels. The structure of in 4 The transmission frame shown is based on the assumption that real-time media data, IP data and object data are shown as three types of data.

Regarding 4 Contains the virtual real-time media data channel 420 a first sub-data channel R-1 and a second sub-data channel R-2, both for transmitting real-time media data, such as video data; As an A / V data stream. The virtual IP data channel 430 includes a sub-data channel IP-1 for transmission of IP data. The virtual object data channel 440 includes a first sub-data channel O-1, a second sub-data channel O-2, a third sub-data channel O-3 and a fourth sub-data channel O-4, which are used to To transmit object data that is used in real time or after being received and received and stored by a device for receiving a broadcast service.

One individual service includes at least one service component. To one Users need to provide a service, the device must receive Consequently, the broadcast service receives service components that to form the service. A sub data channel is a path over which a single service component is transmitted. Around To access a particular service, the device must be for Receive the broadcast service thus the location of sub-data channels Know about the service components that make up the service form, be transferred.

Service access information for access to service components that constitute a service is in the signaling packet 410 out 4 included in the service information area 310 out 3 equivalent. The signaling package 410 contains the service access information described above with respect to 3 is described. As in 4 shown, contains the signaling packet 410 a header information field, a location map table (LMT) field, a link information table (LIT) field, and payload.

The LMT field provides information about the configuration and the physical location of sub-data channels within a transmission frame.

The LIT field provides service configuration information, namely how many services are transmitted over a transmission frame and from which sub-data channels each service is to be transferred. In other words, a LIT refers to information which indicate which sub-data channels whose number is at least one is to be used to form each service.

Regarding 4 shows the LIT field of the signaling packet 410 to service 1, service 2 and service 3 via the transmission frame 400 be transmitted. In addition, the LIT field indicates that the service 1 is the first and second sub-data channels R-1 and R-2 of the real-time virtual media data channel 420 and the third sub-data channel O-3 of the virtual object data channel 440 contains.

The 5A and 5B show a structure of an LMT field according to an embodiment of the present invention. Regarding 5A and 5B According to the current execution, the LMT field contains a type bitmap field, a version number field, and at least one sub data channel number field.

The Type bitmap field indicates which data in a transmission frame, which is transmitted in a predetermined cycle, are included. It is assumed that the transmission frame Object data, audio and video (A / V) data and IP data transmits.

The Type bitmap field consists of 3 bits that can indicate whether A / V data, IP data and object data are available. For example A bit '1' for the type bitmap field indicates presence of data corresponding to the bit, and a bit '0' for the Type bitmap field indicates the absence of data that is the Bits match, on. Consequently, if the type bitmap field is 111 A / V data, IP data and object data all in the transmission data stream contain. Meanwhile, when the type bitmap field is 011, A / V data is not included in the transmission stream, and IP data and object data are both included in the transmission data stream.

The Version Number field displays the version number of the LMT field.

A sub-data channel number in the sub-data-channel-number field denotes the number of sub-data channels belonging to each type of virtual data channel. The sub-data channel number corresponds to the number of channel pointers indicating the physical addresses of the sub-data channels belonging to each virtual data channel. Regarding 5A For example, for real-time media data, the channel pointer fields are first through 1-th channel pointer fields, IP data channel pointers are (1 + 1) th through m th channel pointer fields and channel Pointers for object data are (m + 1) th to nth channel pointer fields. Here, l, m and n denote integers equal to or greater than 0. For example, if no real-time media data is being transmitted over a transmission stream, there may be no sub-data channel number fields for real-time media data and no channel pointer fields for real-time media data.

To the For example, if the value of the type bitmap field is 100, and the value of the at least one sub data channel number field 2 is two channel pointer fields, each two channel pointers of two sub-data channels that transmit real-time media data will be displayed next to the sub data channel number field.

in the LMT field contains each channel pointer field information, which indicate the physical location of each sub-data channel. Index numbers can be assigned sequentially to the channel pointer fields. The sequentially assigned to the channel pointer fields of the LMT field Index numbers are called LMT index numbers. The LMT index numbers are not included in the channel pointer fields when the corresponding transmission data stream is generated, and instead, a device for receiving For a broadcast service, the LMT index numbers sequentially follow the channel pointer fields while evaluating the LMT field. In this In this case, the LMT index numbers are assigned sequentially without the Differentiate types of sub-data channels.

When the value of the type bitmap field is 011, the value of the sub data channel number field for IP data is 2, and the value of the sub data channel number field for object data is 3 , the LMT field may be constructed as in 5B shown. In 5B first and second channel pointer fields show the location of the sub data channels for IP data and third to fifth channel pointer fields show the location of sub data channels for object data. Here, the first to fifth channel pointers are sequentially numbered with the LMT index numbers 1 to 5.

alternative however, LMT index numbers may be the channel-dot fields sequentially according to types of virtual data channels, which are indicated by the channel point fields. In other words, the sub-data channels separated according to the types of sub-data channels numbered.

In this case, the first and second channel pointer fields are numbered with index number 1 and index number 2, and the third, fourth and fifth channel pointer field is respectively index numbered 1, 2 and 3 numbered. Thus, it is not clear if index number 1 belongs to the first channel pointer field or the third channel pointer field. This problem can be solved by further including information used to determine if the corresponding index number is associated with a virtual IP channel or virtual object channel. Information indicating which type of virtual data channel corresponds to an index number will be explained later with reference to FIG 6B described.

5C shows a structure of an LMT field 500 according to another embodiment of the present invention. Regarding 5C is the LMT field 500 according to the current version in a LMT cover field 501 , a version number field 502 , a signaling encapsulation packet (SEP) flag field 503 , an LMT boundary field 504 , a SEP pointer field 505 , a first display field 506 , an A / V data channel pointer field 507 , a second display field 508 , an IP data channel pointer field 509 , a third display field 510 and an object data channel pointer field 511 divided.

The LMT Cover Field 501 indicates the number of LMT fields that have the same version as the LMT field 500 , If, for example, the version of the LMT field 500 1 and a bit value of the LMT coverage field 501 '00001', the number of LMT fields having the version '1' is the one after the LMT 500 to be transferred, 1.

The version number field 502 shows the version of the LMT field 500 at.

The SEP flag field 503 indicates if the LMT field 500 contains a signaling packet. The signaling packet may include additional data for use in processing the transmission frame, such as e.g. LMT or LIT, or may include additional data associated with services packaged in a transmission data stream, such as e.g. An electronic program guide (EPG) or an electronic service guide (ESG). If the bit value of the SEP flag field 503 '1' is the SEP pointer field 505 indicating the location of the signaling packet, next to the SEP flag field 503 available. The LMT limit field 504 displays the range of packets from the LMT field 500 to be influenced. For example, the LMT limit field 504 the address of the last packet indicate that the LMT field 500 affects, or the number of packets, the LMT field 500 influence. If the LMT limit field 504 the address of the last packet indicates that the LMT field 500 For example, packets that come before the address of the last packet are determined to be packets containing the LMT field 500 influence. This means that there is a new LMT field at the address next to the address indicated by the LMT limit field 504 is shown. Consequently, the use of the LMT boundary field allows 504 it's easy to predict the location of the next LMT field.

The SEP pointer field 505 indicates the location of the signaling packet.

The first ad field 506 indicates whether there is a sub data channel. If the value of the first display field 506 '1', there is a channel pointer next to the first display field 506 , Regarding 5C shows the first display field 506 the presence of an A / V sub-data channel.

The A / V Data Channel Pointer field 507 indicates the location of the A / V sub data channel.

The second display field 508 indicates if there is an additional sub data channel. If the value of the second display field 508 '1', there is next to the second display field 508 a channel pointer. Regarding 5C shows the second display field 508 the presence of an IP sub-data channel.

The IP data channel pointer field 509 indicates the location of the IP sub-data channel.

The third ad field 510 shows similar to the second indicator 508 whether there is an additional sub-data channel. If the value of the third display field 510 '1' is, there is next to the third display field 510 a channel pointer. Regarding 5C shows the third display field 510 the presence of an object sub-data channel.

The Object Data Channel Pointer field 511 indicates the location of the object sub-data channel.

The device for receiving a broadcast service may know the number of sub-data channels by using the first, second and third indicators 506 . 508 and 510 used, and can know the location of the sub-data channels by using the channel pointers 507 . 509 and 511 used.

6A shows the structure of a LIT field according to an embodiment of the present invention. Regarding 6A According to the current implementation, the LIT field contains a service number field, a version number field, and at least one service field indicating at least one service.

The Service Count field displays the number of services that are in one individual transmission frames according to the present invention.

The Version Number field displays the version of the LIT field.

each the service fields contain a service identifier field (SID) and at least one LMT index number field. As in the above Structure of the LIT field shows the at least one LMT index number field at least one number associated with at least one channel pointer is. Consequently, the apparatus can receive a broadcast service the physical addresses of sub-data channels, the correspond to a desired service, from the transmission frame know by evaluating the LIT field.

For example, suppose that the device for receiving a broadcast service evaluates a signaling packet of a received transmission stream in which an LMT field as in 5B is shown, an nth service field, as in 6A 1, a first LMT index number field and a second LMT index number field, and the values of the first and second index number fields are 2 and 5, respectively. In this case, the device for receiving a broadcast service interprets the nth service as a service, the service comprising data contained in a sub-data channel having the physical location defined by the second channel. Pointer field in 5B is displayed and data contained in a sub-data channel having the physical location indicated by the fifth channel pointer field shown in FIG 5B is displayed is displayed. Consequently, if the nth service is desired, the broadcast service receiving device does not process all the transmission packets contained in the transmission flow, and instead only processes the data transmitted over transmission packets contained in sub data channels the physical locations indicated by the second and fifth channel pointer fields, thereby processing broadcast data quickly and efficiently.

6B Fig. 10 shows a structure of a LIT array according to another embodiment of the present invention. Regarding 6B According to the current implementation, the LIT field contains a service number field, a version number field, and at least one service field indicating at least one service.

each The service fields contain a SID and at least one channel information field.

For example, suppose that the LMT field of a transmission stream, as in 5B and sequential LMT index numbers are independently assigned to the channel pointer fields corresponding to the types of sub data channels indicated by the channel pointer fields. In other words, the sub-data channels are independently numbered with index numbers corresponding to the types of data. In addition to this, we suppose that an nth service, which in 6B shown contains two sub-data channels. Consequently, the nth service field contains 6B a first channel information field and a second channel information field.

In this case, the first and second channel pointer fields are in 5B shown sub-data channels for IP data, numbered with index number 1, or index number 2, and the third, fourth, and fifth channel pointer fields in 5B Sub data channels corresponding to object data shown are numbered with the index numbers 1, 2 and 3, respectively.

each The channel information fields contain a type information field and an LMT index number field.

The Type information field consists of 2 bits and shows the type of sub data channel which corresponds to a LMT index number. A data value '01' of the Type information field can indicate that the sub data channel, which corresponds to an LMT index number, a sub-data channel for IP data is. On the other hand, a data value may be '10' of the type information field show that the sub data channel is an LMT index number is a sub data channel for object data.

The LMT index number field consists of 5 bits.

If the value of the first channel information field is '0100010' 2 upper bits indicate a virtual IP sub-data channel, and 5 lower ones Bits indicate a channel pointer having an LMT index number of 2. Thus, one can know that the nth service contains the data which are contained in the sub-data channel at the physical location, which is indicated by the second channel pointer field.

If the value of the second channel information field is '1000011' 2 upper bits indicate a virtual object sub-data channel, and 5 lower bits indicate a channel pointer that has an LMT index number 3 has. Consequently, one can know that the nth service also contains the data contains in the sub-data channel at the physical Are included by the fifth channel pointer field is shown.

If the nth service is desired processes the device therefore, not all in the transmission stream for receiving a broadcast service contained transmission packets, and processed instead transmit only those transmission packets contained in sub-data channels Data at the physical locations by the second and fifth Channel Pointer field will be displayed, making broadcasting data fast and processed efficiently.

7A FIG. 10 is a flowchart showing a method of evaluating an LMT field and a LIT field in a broadcast service receiving apparatus according to an embodiment of the present invention. The LMT field is transmitted at regular intervals and is in a predetermined range of a transmission frame.

Regarding 7A For example, in operation S701, when the broadcast service receiving apparatus receives a transmission frame, it acquires and interprets a signaling packet containing service access information which is in a predetermined area of the transmission frame ,

In Operation S703 determines the device for receiving a broadcast service, whether an LMT field is present in the signaling packet. When in Operation S703 is detected in the signaling packet there is no LMT field is detected in operation S705, whether a previous LMT field in the apparatus for receiving a broadcast service was saved. When it is determined in operation S705 that in the apparatus for receiving a broadcast service, a previous one LMT field exists, the procedure continues with the operation S711 continues.

If In operation S703 it is found that in the signaling packet an LMT field is present determines the device for reception a broadcast service in operation S707 corresponding to that in the LMT field version information contained, whether the version of the LMT field was updated. When it is determined in operation S707 that The version of the LMT field has been updated to become the LMT field evaluated in operation S709. By evaluation of the LMT field in Operation S709 will provide information about the location of the sub-data channels receive.

In Operation S711 determines the device for receiving a broadcast service, whether there is a LIT field in the signaling packet. When in Operation S711 is detected in the signaling packet no LIT field exists, is detected in operation S713, whether a previous LIT field in the device for receiving a broadcast service is available. When it is determined in operation S713 that in the device for receiving a broadcast service a previous one LIT field exists, the procedure continues with the operation S719 continues.

If it is determined in operation S711 that the LIT field is present in the signaling packet, the device for receiving a broadcast service in operation S715 determines according to the version information contained in the LIT field whether the version of the LIT field is updated has been. If it is determined in operation S715 that the version of the LIT field has been updated, the LIT field is evaluated in operation S717. By evaluating the LIT field in operation S717 Get connection information about each service, that is, service configuration information.

In Operation S719 will be taken from the results of the evaluation of the LMT field and the LIT field receive services and then processed.

7B FIG. 10 is a flowchart showing a method of evaluating an LMT field and a LIT field according to another embodiment of the present invention. FIG. In 7B The position of the LMT field and a cycle in which the LMT field is inserted in a transmission frame vary. Operations in 7B marked with the same reference numbers as in 7A , are the same operations as in 7A and thus a detailed description thereof will be omitted.

Regarding 7B In operation S720, an LMT field is extracted from a transmission frame corresponding to the LMT pointer information extracted from a previous LMT field. The LMT pointer information points to the location of the next LMT field. Consequently, even if it is omitted to insert the LMT field into a predetermined area of the transmission frame, the LMT field can be easily taken out of the transmission frame.

In Operation S703 determines the device for receiving a broadcast service, whether an LMT field exists at a location specified by the LMT pointer information referred to as. When it is determined in operation 703 that the location indicated by the LMT pointer information, If there is an LMT field, the procedure continues with operation S707 continues. On the other hand, if it is found in operation 703, that at the location designated by the LMT pointer information If no LMT field is present, the procedure continues continued with operation S730. If at the location indicated by the LMT pointer information is designated, no LMT field is present, this means one Case where the LMT field is omitted and a case in which an error is generated in the LMT field.

In Operation S730 is performed according to the information about LMT number with identical version, in a previous LMT field is included, determines if the previous LMT field is valid is. The fact that the previous LMT field is valid, means that the previous LMT field is used continuously can. If in operation S730 it is determined that the previous one LMT field is valid, the procedure continues with the Operation S711 continues.

In The description refers to the information about the number of LMTs with identical version, the number of LMT fields that are identical Have version. For example, suppose that the previous LMT field is referred to as a first LMT field. The first LMT field contained information about the number of LMTs with identical Version refers to the number of LMTs that have the same version as to transmit those of the first LMT field and after the first LMT field (or to receive). If included in the first LMT field Information about the number of LMTs with identical version '3', there are three LMTs that have the same version as the first LMT field. Consequently, if included in the first LMT field Information about the number of LMTs with identical version is equal to or greater than '1', the version of the LMT field contained in a current frame is the same like those of the first LMT field, and thus can in the current Frame contained packets using the first LMT field are processed.

8th Fig. 10 is a block diagram showing a structure of a broadcasting service transmitting apparatus 800 according to an embodiment of the present invention. Regarding 8th contains the device for transmitting a broadcast service 800 a unit for packetizing broadcast data 810 , a unit for generating transmission packets 820 , a transmission frame generation unit 830 and a transmission unit 840 ,

The unit for packetizing broadcast data 810 packetizes at least one type of broadcast data to thereby generate at least one broadcast data packet. The broadcast data includes application data such as real-time media data (eg, an A / V data stream), IP data, object data, etc., and signaling data such as program-specific information (PSI), service information, and so forth. Information (SI) and metadata. For example, the application data may be packetized according to a system standard MPEG-4.

The unit for generating transmission packets 820 generates at least one transmission packet for transmission of the at least one broadcast data packet. The transmission packet may be the same size as a packet of MPEG-2 transmission data stream. However, according to an embodiment of the present invention wherein service access information is included in a predetermined area of a transmission frame, inclusion of a packet identifier in a transmission packet such as inclusion of a PID in a packet of MPEG is -2 transmission data stream, not required. According to another embodiment of the present invention, wherein service access information is not included in a predetermined area of a transmission frame, the inclusion of a packet identifier in an override is also included is not required because the service access information contains information about the location of the next service access information.

The unit for generating transmission frames 830 generates a transmission frame having a predetermined size for transmission of the at least one broadcast service formed using the at least one transmission packet. As in 4 The unit forms the transmission frame generation unit 830 at least one transmission packet in at least one sub-data channel and generates a transmission frame containing the at least one sub-data channel.

The unit for generating transmission frames 830 generates the transmission frame such that service access information for access to the at least one broadcast service transmitted over the transmission frame is included in the transmission frame. To achieve this function, the transmission frame generating unit can be used 830 a service access information generating unit 832 for generating the service access information.

As described above, the service access information can be transmitted by placing them in a predetermined area of the transmission frame is included, for example in a first packet of the transmission frame. By determining the location of the service access information can a device for receiving a broadcast service easily on access the service access information stored in a transmission frame is included. However, the service access information is not necessarily in the predetermined area of the transmission frame contain. The reason is that to the next Service access information can be easily accessed by the location information about the next service access information, used in the current service access information becomes.

The transmission frame includes at least one virtual channel that corresponds to the data type a distinction is made. Each of the at least one virtual channels includes at least one sub-data channel. A sub-data channel Each of the at least one service components corresponds to one Broadcast service within a transmission frame.

The Service access information includes an LMT, which is the location of each Under data channel indicates that in the transmission frame is included, and a LIT containing information about the Configuration of at least one broadcast service transmitting over the transmission frame is displayed.

The LMT contains type information indicating the type of data transmitted over the transmission frame version information that indicates the version of the LMT, Sub-channel number information showing the number of sub-channels which correspond to each data type, and channel pointer information, indicating the location of each of the sub-data channels. The LMT may also provide at least part of information about identical version LMT numbers indicating the number of LMTs which have an identical version, LMT pointer information, the show the location of a next LMT, information about the number of extra data representing the number of parts additional data associated with the at least one broadcast service are connected, display, and pointer information additional data representing the location of each part of additional Show data include.

The LIT contains service-number information that indicates the number of broadcast services transmitting over the transmission frame be version information that indicates the version of the LIT and service information, which is the configuration of each of the services Show. The service information includes an index number, which is associated with the channel pointer information contained in the LMT is. If index numbers sequentially specify the channel pointer information be assigned, but independently according to the types of sub-data channels specified by the channel pointer, The service information can be type information and index numbers include as described above. In this case, the type information indicates which Type of sub-data channel assigned a corresponding index number is.

The transmission unit 840 sequentially transmits a series of transmission frames transmitted by the transmission frame generation unit 830 be generated at intervals of a predetermined period. The transmission unit 840 may generate an ATSC frame in which at least one transmission frame is inserted and send the ATSC frame according to an ATSC system standard.

9 FIG. 10 is a flow chart illustrating a method of transmitting a broadcast service included in the apparatus for broadcasting broadcasting 800 out 8th is executed according to an embodiment of the present invention.

Regarding 8th and 9 In operation S910 packages the unit for packetizing broadcast data 810 the device for transmission a broadcasting service 800 at least one type of broadcast data, thereby generating at least one broadcast data packet.

In operation S920, the transmission packet generating unit generates 820 at least one transmission packet for transmitting the at least one broadcast data packet.

In operation S930, the transmission frame generating unit generates 830 a transmission frame having a predetermined size to transmit at least one broadcast service constructed using the generated at least one transmission packet. In operation S930, the transmission frame is generated so that the service access information for access to the at least one broadcast service transmitted over the transmission frame is included in the transmission frame.

In operation S940, the transmission unit transmits 840 a set of transmission frames provided by the transmission frame generation unit 830 be generated. The transmission frames may be transmitted sequentially at intervals of a predetermined period.

10 Fig. 10 is a block diagram showing a structure of a broadcasting service receiving apparatus 1000 according to an embodiment of the present invention. Regarding 10 contains the device for receiving a broadcast service 1000 according to the current version, a receiving unit 1010 , a unit for processing a transmission frame 1020 , a unit for processing a transmission packet 1030 , a unit for processing broadcast data 1040 and a user input unit 1050 ,

The receiving unit 1010 receives at least one transmission frame having a predetermined size. The receiving unit 1010 may be constructed to receive an ATSC frame and to acquire the at least one transmission frame from the ATSC frame.

The unit for processing a transmission frame 1020 acquires service access information from the transmission frame for access to at least one broadcast service. Thereafter, the unit acquires to process a transmission frame 1020 from the transmission frame also at least one transmission packet for transmission of at least one broadcast data packet using the service access information. When the service access information is in a predetermined area of the received transmission frame, the unit acquires to process a transmission frame 1020 the service access information from the predetermined area of the received transmission frame. On the other hand, when the service access information is not in the predetermined area of the received transmission frame, the transmission frame processing unit acquires 1020 the service access information from the received transmission frame based on the location information included in the previous service access information. The location information included in the current service access information indicates information about the location of the next service access information.

More specifically, the unit evaluates the processing of a transmission frame 1020 an LMT field and a LIT field, which are the service access information, accessing sub data channels for each service. When one of a plurality of services transmitted over the transmission frame is selected, the unit transmits a transmission frame processing 1020 to the unit for processing a transmission packet 1030 Transmission packets contained in sub-data channels forming the selected service.

The operation of selecting one of the plurality of services transmitted over the transmission frame may be performed in accordance with a user input signal via the user input unit 1050 Will be received. When a user selects a service, only the transmission packets included in the sub-data channels constituting the selected service may be taken to the transmission packet processing unit 1030 be transferred and processed by her. Consequently, it is not necessary to perform a conventional operation of evaluating all PIDs contained in transmission packets and to filter out only the transmission packets having a predetermined PID.

The unit for processing a transmission packet 1030 processes the at least one of the transmission frame processing unit 1020 received transmission packet, thereby acquiring at least one broadcast data packet from the at least one transmission packet. The unit for processing a transmission packet 1030 may further include a head information changing unit (not shown). If in the acquired Broadcast data packet is an error, the unit for changing the header information changes the value of the header information of the erroneous broadcast data packet to a predetermined value. At this time, the header information changing unit may change the value of the header information of the erroneous broadcast data packet to a value of the header information that the header information of general packets may not have. For example, the header information of the erroneous broadcast data packet may include both information indicating that the erroneous broadcast data packet is not the first packet and information indicating that decoding information is in the erroneous broadcast data packet are included. The above-described header information of the erroneous broadcast data packet is false because it is assumed that decoding information is transmitted with the first packet. According to the present invention, a faulty packet can be detected without using bits, in contrast to the prior art, where bits are used to indicate a faulty packet. Thus, the amount of transmitted data can be reduced.

The unit for processing broadcast data 1040 processes the at least one broadcast data packet. The unit for processing broadcast data 1040 can be implemented as a decoder for processing broadcast data encoded according to the standard of the MPEG-4 system.

11 FIG. 10 is a flowchart showing a method of receiving a broadcast service according to an embodiment of the present invention. FIG.

Regarding 11 At least one transmission frame having a predetermined size is received in operation S1110.

In Operation S1120 will access service access information for access at least one broadcast service from the transmission frame purchased, and at least one transmission packet for transmission At least one broadcast data packet is generated using the Service access information also from the transmission frame acquired.

In Operation S1130 will be the at least one transmission packet processed so that at least one broadcast data packet from the at least one transmission package is purchased.

In Operation S1140 processes the at least one broadcast data packet.

The Invention can also be used as computer-readable code on a computer readable Recording medium are embodied. Functional programs, Codes and code segments for executing the present Invention can easily be done by programmers with normal Knowledge to which the present invention applies, be constructed. The computer readable recording medium is each device for data storage, which can store data afterwards from one Computer system can be read. examples for the computer-readable recording medium is read-only memory (ROM), Read / write memory (RAM), CD-ROMs, magnetic tapes, floppy disks, optical disks, flash memory and so on. The computer readable Recording medium can also be coupled via networked Computer systems be distributed so that the computer-readable code is stored and executed in a distributed manner.

Even though the present invention in particular with reference to exemplary Embodiments shown and described, understands a Professional that various changes in form and details can be made without mind and girth to depart from the present invention, as by the following Claims defined.

Summary

It become a device and a method of transmission a broadcasting service and a device and a method for receiving a broadcast service for providing a broadcast service, made up of different types of data. The device for receiving a broadcast service comprises a Receiving unit, a transmission frame processing unit, a unit for processing the transmission packet and a unit for processing the broadcast data. The receiving unit receives a transmission frame, one before has fixed size. The unit for processing of the transmission frame acquires from the transmission frame Service access information for access to at least one broadcast service, and also acquires at least one transmission packet for transmission from the transmission frame at least one broadcast data packet using the service access information. The unit for processing the transmission packet processes the at least one transmission packet by at least one Broadcast data packet from the at least one transmission packet to acquire. The unit for processing the broadcast data is processed the at least one broadcast data packet.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• KR 10-2007-0077165 [0042]
• KR 10-2007-00124371 [0042]

Claims (46)

Device for transmitting a broadcasting service, full: A unit for packetizing broadcast data, the at least one type of broadcast data packetized to at least to generate a broadcast data packet; a unit for production of transmission packets containing at least one transmission packet for transmitting the at least one broadcast data packet generated; a unit for generating transmission frames, which generates a transmission frame that is one before has fixed size, to transfer the at least one broadcast service associated with the at least one broadcast packet is formed; and a transmission unit that transmits the transmission frame, in which the transmission frame generating unit transmits the transmission frame generated, so that service access information to access the at least one broadcast service transmitting over the transmission frame is included in the transmission frame. Device for transmitting a broadcasting service of claim 1, wherein the service access information is in a previously set range of the transmission frame. Device for transmitting a broadcasting service of claim 1, wherein the service access information includes location information about contains the next service access information. Device for transmitting a broadcasting service of claim 1, wherein: the transmission frame at least contains a virtual data channel corresponding to A distinction is made between data types; and each of the at least one virtual data channels at least one sub-data channel contains at least one transmission packet contains. Device for transmitting a broadcasting service Claim 1, wherein the service access information is a map table (Location Map Table, LMT) that contains information that show a physical location of sub data channels, the service components correspond to the at least one broadcast service which is included in the transmission frame and a connection information table (Linkage Information Table, LIT), the information about contains the configuration of the at least one broadcast service, which is included in the transmission frame. Device for transmitting a broadcasting service of claim 5, wherein the LMT type information, the types of data which are transmitted via the transmission frame version information showing the version of the LMT, sub-data channel number information, which is a number of sub-data channels, of any data type and channel pointer information, the locations of the sub-data channels show contains. Device for transmitting a broadcasting service of claim 6, wherein the LMT further comprises at least part of information about identical version LMT numbers indicating a number of LMTs, which have the same version as the LMT, LMT pointer information, showing a location of a next LMT, information about the number of extra data representing the number of parts additional data associated with the at least one broadcast service are connected, display, and pointer information additional data showing the location of the additional View data includes. Device for transmitting a broadcasting service claim 5, wherein the LIT service number information comprising a Display number of broadcast services broadcasting over the transmission frame version information that indicates a version of the LIT, and service information, which is a configuration of the broadcast services show includes. Device for transmitting a broadcasting service Claim 8, wherein the service information is LMT index numbers which are associated with the channel pointer information that indicates the location of the sub-data channels. Device for transmitting a broadcasting service Claim 1, wherein the transmission unit comprises an ATSC frame generates and transmits in the at least one transmission frame Claim 1 is inserted. A method of broadcasting a broadcast service, comprising: packetizing at least one type of broadcast data to produce at least one broadcast data packet; Generating at least one transmission packet for transmission of the at least one broadcast data packet; Generating a transmission frame having a predetermined size for transmitting at least one broadcast service formed with the at least one transmission packet; and transmitting the transmission frame, the transmission frame being generated to provide service access information for access to the at least one broadcast service transmitted over the transmission frame. Method for transmitting a broadcasting service of claim 11, wherein the service access information is in a previously set range of the transmission frame. Device for transmitting a broadcasting service claim 11, wherein the service access information includes location information about contains the next service access information. Method for transmitting a broadcasting service of claim 11, wherein: the transmission frame at least contains a virtual data channel corresponding to the data types are differentiated; and each of the at least a virtual data channels at least one sub-data channel contains the at least one transmission packet contains. Method for transmitting a broadcasting service Claim 11, wherein the service access information is a map table (Location Map Table, LMT) that contains information that show a physical location of sub data channels, the service components correspond to the at least one broadcast service which is included in the transmission frame and a connection information table (Linkage Information Table, LIT), the information about contains the configuration of the at least one broadcast service, which is included in the transmission frame. Method for transmitting a broadcasting service of claim 15, wherein the LMT type information, the types of View data transmitted over the transmission frame version information that indicates a version of the LMT, Sub-data channel number information representing a number of sub-data channels, which correspond to each data type, and channel pointer information, which indicate the locations of the sub-data channels. Method for transmitting a broadcasting service claim 16, wherein the LMT further comprises at least a portion of Information about identical version LMT numbers that show a number of LMTs that have the same version as the LMT, LMT pointer information, which is a location of a next LMT, information about the number of additional Data representing the number of pieces of additional data that are associated with the at least one broadcast service, and information about pointers of additional data, which indicates the location of the additional data. Method for transmitting a broadcasting service claim 15, wherein the LIT service number information, the indicate a number of broadcast services transmitting over the transmission frame version information that indicates a version of the LIT, and service information, which is a configuration of the broadcast services show includes. Method for transmitting a broadcasting service Claim 18, wherein the service information is LMT index numbers which are associated with the channel pointer information that indicates the location of the sub-data channels. Method for transmitting a broadcasting service of claim 11, further comprising generating and transmitting an ATSC frame comprises, in the at least one transmission frame Claim 11 is inserted. Apparatus for receiving a broadcast service, full: A receiving unit, which has a transmission frame receives, which has a predetermined size; a Unit for processing the transmission frame, the from the transmission frame service access information to Receive access to at least one broadcast service and also at least one transmission packet from the transmission frame for transmitting at least one broadcast data packet obtained using the service access information; a Unit for processing a transmission packet, the the at least one transmission packet is processed to the at least one broadcast data packet from the at least one transmission packet to acquire; and a unit for processing the broadcast data, the processing at least one broadcast data packet. Apparatus for receiving a broadcast service claim 21, wherein the service access information is in a previously set range of the transmission frame. Apparatus for receiving a broadcast service of claim 21, wherein: the service access information location information about contains the next service access information; and the unit for processing a transmission frame the service access information from the transmission frame based on location information obtained in the previous service access information are included. The apparatus for receiving a broadcast service of claim 21, wherein: the service access information includes information about a number of parts of the service access information having the same content as the service access information; and the transmission frame processing unit further includes an acquired service access information recovering unit based on the previous service access information when there is an error in the obtained service access information. Apparatus for receiving a broadcast service of claim 21, wherein: the transmission frame at least contains a virtual data channel corresponding to A distinction is made between data types; and each of the at least one virtual data channels at least one sub-data channel contains the at least one transmission packet contains. Apparatus for receiving a broadcast service Claim 21, wherein the service access information is a site map table (Location Map Table, LMT) that contains information that show a physical location of sub data channels, the service components correspond to the at least one broadcast service which is included in the transmission frame and a connection information table (Linkage Information Table, LIT), the information about contains the configuration of the at least one broadcast service, which is included in the transmission frame. Apparatus for receiving a broadcast service from claim 26, wherein the LMT type information, the types of View data transmitted over the transmission frame version information that indicates a version of the LMT, Sub-data channel number information representing a number of sub-data channels, which correspond to each data type, and channel pointer information, which indicate the locations of the sub-data channels. Apparatus for receiving a broadcast service claim 27, wherein the LMT further comprises at least a portion of Information about identical version LMT numbers that show a number of LMTs that have the same version as the LMT, LMT pointer information, which is a location of a next LMT, information about the number of additional Data containing a number of pieces of additional data, the are associated with the at least one broadcast service, and information about pointers of additional data, which indicates the location of the additional data. Apparatus for receiving a broadcast service Claim 26, wherein the LIT service number information, the indicate a number of broadcast services transmitting over the transmission frame version information that indicates a version of the LIT, and service information, which is a configuration of the broadcast services show includes. Apparatus for receiving a broadcast service of claim 29, wherein the service information comprises index numbers, which are associated with the channel pointer information indicating the location of the Displays sub-data channels. Apparatus for receiving a broadcast service Claim 21, wherein the receiving unit receives an ATSC frame and at least one transmission frame from the ATSC frame acquires from claim 21. Apparatus for receiving a broadcast service of claim 21, wherein: the unit for processing a transmission frame further includes a head information changing unit, if there is an error in the acquired broadcast data packet, a value of the header information of the erroneous broadcast data packet to change to a predetermined value of the header information; and the unit for processing broadcast data at least a broadcast data packet from the at least one broadcast data packet does not process the predetermined value of the header information Has. Method for receiving a broadcasting service, full: Receiving a transmission frame, the has a predetermined size; from the transmission frame Acquire service access information for access to at least a broadcast service and also the broadcast frame Acquire at least one transmission packet for transmission at least one broadcast data packet using the service access information; To process of the at least one transmission packet to at least a broadcast data packet from the at least one transmission packet to acquire; and Processing the at least one broadcast data packet. A method of receiving a broadcast service of claim 33, wherein the service access information is in a previously set range of the transmission frame. The method of receiving a broadcast service of claim 33, wherein: the service access information is location information about the next service access information; and obtaining the transmission packet comprises obtaining the service access information from the transmission frame based on location information included in the previous service access information. A method of receiving a broadcast service of claim 33, wherein: the service access information information about a Contains number of parts of the service access information, having the same content as the service access information; and the Purchasing the Transfer Packet also restores the obtained service access information based on the Previous service access information includes if purchased in the Service access information is an error. A method of receiving a broadcast service of claim 33, wherein: the transmission frame at least contains a virtual data channel corresponding to A distinction is made between data types; and each of the at least one virtual data channels at least one sub-data channel contains at least one transmission packet contains. A method of receiving a broadcast service of claim 33, wherein the service access information is a site map table (Location Map Table, LMT) that contains information that show a physical location of sub data channels, the service components correspond to the at least one broadcast service which is included in the transmission frame and a connection information table (Linkage Information Table, LIT), the information about contains the configuration of the at least one broadcast service, which is included in the transmission frame. A method of receiving a broadcast service from claim 38, wherein the LMT type information, types of View data transmitted over the transmission frame version information showing the version of the LMT, sub-data channel number information, which is a number of sub-data channels, of any data type correspond, and channel pointer information representing the locations of the sub-data channels show contains. A method of receiving a broadcast service claim 39, wherein the LMT further comprises at least a portion of Information about identical version LMT numbers that show a number of LMTs that have the same version as the LMT, LMT pointer information, which is a location of a next Display LMT, information about the number of additional data, which contains a number of pieces of additional data the at least one broadcast service are connected, and information about pointers of additional data, which indicates the location of the additional data. A method of receiving a broadcast service claim 38, wherein the LIT service number information, the indicate a number of broadcast services transmitting over the transmission frame version information that indicates a version of the LIT, and service information, which is a configuration of the broadcast services show includes. A method of receiving a broadcast service of claim 41, wherein the service information comprises index numbers, which are associated with the channel pointer information indicating the location of the Displays sub-data channels. Apparatus for receiving a broadcast service of claim 33, wherein receiving the transmission frame receiving an ATSC frame and acquiring from the ATSC frame at least one transmission frame of claim 33. A method of receiving a broadcast service of claim 33, wherein: acquiring the broadcast data packet it further includes, if included in the acquired broadcast data packet Error exists, a value of the header information of the faulty Broadcast data packet to a predetermined value of header information to change; and when processing the broadcast data packet at least a broadcast data packet from the at least one broadcast data packet, which does not have the predetermined value of the header information is processed. A computer readable recording medium having recorded thereon a program for a method of broadcasting a broadcasting service, comprising: packetizing at least one type of broadcasting data to produce at least one broadcasting data packet; Generating at least one transmission packet for transmission of the at least one broadcast data packet; Generating a transmission frame having a predetermined size for transmitting at least one broadcast service formed with the at least one transmission packet; and transmitting the transmission frame, whereby the transmission frame is generated that it contains service access information for access to the at least one broadcast service transmitted over the transmission frame. Computer-readable recording medium on which a Program for a method of receiving a broadcast service recorded, comprising: Receiving a transmission frame, which has a predetermined size; out the transmission frame acquiring service access information for access to at least one broadcast service and also the broadcast frame Acquire at least one transmission packet for transmission at least one broadcast data packet using the service access information; To process of the at least one transmission packet to at least a broadcast data packet from the at least one transmission packet to acquire; and Processing the at least one broadcast data packet.