KR20080012377A - Method and apparatus for hierarchical transmission / reception in digital broadcasting - Google Patents

Abstract

In accordance with various aspects of the invention, there is being provided a method and apparatus for transmitting, and a method and apparatus for receiving a digital broadcast signal comprising a hierarchical modulation having a high priority stream and a low priority stream. The content to be received or transmitted in encoded into two stream so that a first stream is configured to be transmitted or received with the high priority stream, and a second stream to be transmitted/received with the low priority stream is configured to contain additional information for increasing the bitrate of the first stream.

Description

Method and apparatus for hierarchical transmission / reception in digital broadcasting {Method and apparatus for hierarchical transmission / reception in digital broadcast}

The present invention relates to an apparatus for transmitting and / or receiving digital broadcast signals using hierarchical modulation. Furthermore, the present invention also relates to the use of such devices.

Today, multimedia content broadcasting, particularly TV content, towards battery-powered handheld devices (such as cellular mobile phones or PDAs) is considered a promising business opportunity.

With Digital Video Broadcasting-handheld (DVB-H), Digital Video Broadcasting-Terrestrial (DVB-T), Digital Multimedia Broadcast-Terrestrial (DMB-T), Terrestrial Digital Multimedia Broadcasting (T-DMB), and MediaFLO (Forward Link Only) The same examples, digital broadband wireless broadcast technologies, can be used to build such services. Many international forums and R & D projects are dedicated to standardizing, accessing and lobbying for technology and emerging business opportunities, including: Convergence of Broadcast and Mobile Services (CBMS), Multimedia Broadcast Multicast Service (MBMS), and OMA (Open). Mobile AIIiance), BMCO (Broadcast_Mobile_Convergence) forum, DigiTAG (Digital terrestrial television action group), IP Datacast Forum.

The most interesting feature of the DVB-T / H standard is the ability to build networks that can use hierarchical modulation. In general, these systems share one and the same channel for two independent multiplexers.

In hierarchical modulation, the possible digital states of constellation (eg 64 states for 64-QAM, 16 states for 16-QAM) are interpreted differently than in the non-hierarchical case.

In particular, two separate data streams may be made available for transmission: the first stream (HP: high priority) is defined by the number of quadrants in which the state is located (eg special QPSK). Stream), the second stream (LP: low priority) is defined by the position of the state within its quadrant (eg 16-QAM or QPSK stream).

In such known systems, the same with two different resolution / detail levels of hierarchical modulation, for example for use in receivers such as Integrated Receiver Decoders (IRDs) with different capabilities and different reception states. It has been proposed to transmit video content. In Figure 1, IDR A is used to describe the service planned for a mobile receiver in an outdoor reception situation, and IRD C is used to describe the service intended for a portable receiver in an outdoor reception situation according to ETSI TR 102 377. do. Lower resolutions will use HP and higher resolutions will use LP. Therefore, as can be seen from FIG. 1, the same content is disadvantageously transmitted twice.

For example, there are two content streams: low resolution 5 Mbit / s and high resolution 10 Mbit / s. In hierarchical mode, select QPSK for HP and 16QAM for LP to ensure sufficient capacity for transmission. The problem with this choice is that LP: 16QAM performance is worse than non-hierarchical 64QAM. Therefore, mobile reception possibilities for LP streams are very limited.

On the other hand, if QPSK is selected for HP and QPSK is selected for LP, mobile reception capability is sufficient (equivalent to non-hierarchical 16QAM). However, when using this method, the number of services must be limited because LP does not have sufficient capacity for higher resolution streams.

It is an object of the present invention to adapt the coding of hierarchical modulation to flexibly combine the requirements for capacity and performance.

In accordance with various aspects of the present invention, a method and apparatus for transmitting and receiving a digital broadcast signal including hierarchical modulation with multimedia streams of high priority and low priority are provided. Each multimedia stream will contain one or more special encoding types of media streams as well as associated signaling. The source of at least one media content to be received or transmitted is encoded into two streams, such that the first stream is configured to be transmitted or received with a high priority stream and is transmitted or received with a low priority stream. The second stream is configured to include additional information for increasing the bitrate of the first stream.

However, other embodiments of the invention are described in detail in the dependent claims and the description of further embodiments.

The invention will now be described with reference to the accompanying drawings, for illustrative purposes only.

1 illustrates a known system for transmitting DVB signals.

2 shows an example of a system in which a DVB signal is transmitted, where content is encoded according to a further embodiment of the present invention.

3 illustrates a further embodiment of the present invention.

4 illustrates a further alternative embodiment of the present invention.

5 shows a terminal receiving a DVB signal, where the content is decoded in accordance with a further embodiment of the present invention.

6 illustrates a broadcast system in which examples of the present invention may be used.

2 discloses a scalable encoder apparatus 200 applied to a system and / or transmitter of various embodiments. The variable video coder is an example of the variable encoder 200. For example, the resolution or detail level may be variable. The variable encoder device includes a multi-protocol encapsulation (IPE) 201. IPE 201 receives the Service 1, IRD C, variable video basic and enhancement protocol layers as separate IP streams, which are signals 202. The DVB signal 203 includes a first stream 204 and a second stream 205. The first stream is Service 1, IRD C base layer, at high priority (HP). The second stream contains the Service 1, IRD A enhancement layer at low priority (LP). The base layer contains low resolution video and is transmitted with the HP stream. The enhancement layer contains the extra information needed for high resolution video and is sent with the LP stream. Therefore, the content is not transmitted twice but the base layer and enhancements (ie enhancement layer) are transmitted separately.

For example, HP: QPSK, LP: QPSK hierarchical modes are used without limiting the number of services. This is because the enhancements do not require a full 10 Mbit, but for example 5 Mbit available. Thus, good mobile reception is guaranteed. Hierarchical modulation provides a synergistic effect when combined with a variable video codec. In one embodiment of a variable video codec, temporal scalability (frame rate) or spatial variability (number of pixels) may be used. However, in another further embodiment, the rate of the screen is variable. Without a variable video codec, the use of hierarchical modulation is further limited.

According to various further embodiments, also referred to as a service system, the encoder encodes the media streams for user service. The service system knows a priori the number of priority classes provided and the destination media bitrate for the priority classes (two in the case of the hierarchical modulation presented). Alternatively, the IP encapsulation unit (alternatively referred to as multiprotocol encapsulation unit) signals these values to the service system. The service system uses prior knowledge to generate prioritized IP packets based on the importance of the IP packets, either manually or automatically. The number of different priority label values is equal to the known number of provided priority classes. For example, in a news broadcast service, audio has a higher priority than video, and video has a higher priority than secondary media enhancement data. Continuing with the example above, an additional priority assignment is generated in the variable coded video stream to enable base layer IP packets to be assigned a higher priority than enhancement layer IP packets. Practical means for signaling priorities include the following: IP multicast is used and a separate multicast group address is assigned to each priority level. Alternatively, priority bits of the IPv6 packet header may be used. Alternatively, it is often possible to use media-specific markers of priority in RTP payload headers or RTP payloads. For example, the nal_ref_idc element in the RTP payload header of the H.264 RTP payload format may be used. Further, the service system adjusts the bitrate of the IP packet to which a certain priority level is applied to match the known media bitrate of the corresponding priority class. Means for bitrate adjustment include audio and video encoding object bitrate selection. For example, many audio coding methods, such as AMR-WB +, include several modes for different bitrates. Video encoders include a coder control block, which adjusts the output bitrate of the encoder, among others. Means for video bitrate adjustment include picture rate control and quantization step size selection for prediction error pictures. In addition, media encoding can be performed in a variable manner. For example, video may be temporarily variable, the base layer may be determined at a 7.5 Hz image rate, and the base and enhancement layers may both be determined at a 30 Hz image rate. The base layer is then assigned a higher priority than the enhancement layer. Next, there are two priority classes, so the service system creates two sets of IP packet streams, one here referred to as the high priority (HP) stream and the other as the low priority (LP) stream. Consider the case.

Additional Various Embodiments Using Hierarchical Priority Modulation in a Broadcast

In the media compression method, a category of importance can be assigned to individual bit strings of encoded media, which is now called priority. In coded video, for example, non-predictably coded information (intra pictures) has a higher priority than predictively coded information (inter pictures). Among the inter pictures, those used for prediction of other inter pictures (reference picture) have a higher priority than others that are not used for future prediction (non-reference pictures). Some audio coding methods require the presence of codebook information before content playback can begin, in which case the packets carrying the codebook have a higher priority than content packets. When using MIDI, instrument definitions have a higher priority than actual real-time MIDI streams. One skilled in the art will be able to readily identify different priorities in media encoding methods based on the examples presented.

Priorities may be created based on "soft" criteria. For example, when a media stream contains audio and video packets, in most practical cases, from the point of view of the user's perception, it can be assumed that audio information is more important than video information. The audio information then has a higher priority than the video information. Based on what the application needs, those skilled in the art should be able to assign priorities to different media types transmitted in a single media stream.

Loss of packets carrying predictively encoded media usually has a bad effect on the reproduced quality. The missing data not only annoys the media frame to which the packet belongs, but also propagates the error to later frames because of the predictive nature of the encoding process. Most of the media compression methods mentioned above implement the concept of independent decoder playback information (IDR). IDR information has the highest priority among all media bit strings, by its own attribute. Independent decoder reproduction information is defined as information that completely resets the decoder to a known state. In older video compression standards such as ITU-T H.261, the IDR picture is the same as an intra picture. Modern video compression standards such as ITU-T H.264 include reference picture selection. In order to break all prediction mechanisms and reset the reference picture selection mechanism to a known state, such standards include a special picture type called an IDR picture. In the audio and MIDI examples mentioned, the IDR contains all the codebook / instrument information needed for later decoding. The IDR section includes media samples from the IDR sample) to the next IDR sample (excluding) in the decoding order. No coded frame following an IDR frame can reference a frame before an IDR frame.

Scalability of one attribute that is useful for coded bit streams. In the following, bit rate variability is described as referring to the ability of a compressed sequence to be decoded at different data rates. Such a compressed sequence can be streamed via channels having different bandwidths and can be decoded and played back in real time at other receiving terminals.

Variable multimedia is ordered in hierarchical layers of data. The base layer contains individual representations of multimedia clips, such as video sequences, and the enhancement layer contains refinement data in addition to the base layer. The quality of the multimedia clip is gradually improved as enhancement layers are added to the base layer.

Variability is a necessary attribute in heterogeneous, error-prone environments, such as wireless channels in the Internet or cellular communication networks. This property is needed to count limitations such as bit rate, display resolution, network throughput and decoder complexity.

Once the sequence has been downloaded and played back on different devices with different processing capabilities, bit rate variability can be used in devices with low processing capabilities that decode only a portion of the bit stream to provide a lower quality representation of the video sequence. Devices with high processing power can decode and play back sequences with good quality. In addition, bitrate variability means that the processing power required to decode the entire quality representation of a video sequence is lower than when decoding a good quality sequence. This is a figure of computational variability.

If the video sequence is pre-stored in a streaming server, and if the server is to be transmitted as a bit stream, for example to reduce the bit rate momentarily to avoid congestion in the network, the server still transmits the available bit stream while still It would be beneficial if the bit rate of the stream could be reduced. This can be achieved using bit rate variable coding.

Variability can be used to improve the resilience to errors in a transmission system where layered coding is combined with transmission prioritization. The term transmission prioritization is used to describe a mechanism for providing different quality of services in transmission. This includes unequal error protection, which provides different channel error / loss rates and assigns different priorities to support different delay / loss requirements. For example, the base layer of a variably coded bit stream may be delivered through a transport channel that provides a high degree of error protection, while the enhancement layer may be sent in a more error prone channel.

Video variability is sometimes classified into the following types: temporal, spatial, quality and region-of-interest. For all types of video variability, decoding complexity is a monotonically increasing function of the number of enhancement layers. Therefore all types of video variability also provide computational variability.

Temporal variability is for the ability of a compressed sequence to be decoded at different picture rates. For example, a temporally variable encoded stream may be decoded at 30 Hz, 15 Hz, and 7.5 Hz. There are two types of temporal variability: non-hierarchical and hierarchical. In non-hierarchical temporal variability, certain coded pictures are used as prediction references (also known as inter prediction) for motion compensation or any other decoding process for some other coded pictures. These pictures are referred to as non-references in modern standards such as H.264 / AVC. Non-reference pictures may be inter-predicted in output order from previous pictures or in output order from both previous and succeeding pictures. Furthermore, each prediction block in the intermediate prediction may originate from one picture or be a weighted average of two source blocks in bi-prediction encoding. In conventional video coding standards, B-pictures provide a means for temporal variability. B-pictures are positive Predicted non-reference pictures and encoded in output order from both previous and subsequent reference pictures. Among other things, non-reference pictures are used to improve the image quality of the sensed image by increasing the image display rate. They can be dropped without affecting the decoding of successive frames, thus allowing video sequences to be decoded at different rates depending on the limitations of the bandwidth of the transmission network or different decoder capabilities. Non-reference pictures may be able to improve compression performance compared to reference pictures, and their use requires increased memory as well as introducing additional delay.

In hierarchical temporal variability, a particular set of reference and non-reference pictures can be dropped from an encoded bitstream without affecting the decoding of the remaining bitstream. Hierarchical temporal variability requires multiple reference pictures for motion compensation, that is, there is a reference picture buffer that includes multiple decoded pictures from which the encoder can select a reference picture for intermediate prediction. In the H.264 / AVC coding standard, a feature called subsequence enables hierarchical temporal variability, as described below. Each enhancement layer includes subsequences and each subsequence contains many reference and / or non-reference pictures. Subsequence

It includes a number of inter-dependent pictures that can be placed without confusing other subsequences in the lower subsequence layer. Subsequence hierarchies are arranged hierarchically based on their dependency on each other. If a subsequence is placed in the enhancement layer of the top layer, the remaining bitstreams remain in a valid ecology.

Spatial variability allows the criterion of multiple resolution bitstreams to meet changing display requirements / limitations. In spatial variability, the spatial enhancement layer is used to recover the coding loss between the upsampled version of the reconstructed layer and the higher resolution version of the original picture used as a reference by the enhancement layer, which is the reference layer. For example, if the reference layer has a QCIF (Quarter Common Intermediate Format) resolution of 176x144 pixels and a Common Intermediate Format (CIF) resolution of 352x288 pixels, the reference layer picture can be used to ensure that the enhancement layer picture is properly predicted from the base layer picture. It must be variable. There may be multiple enhancement layers, each of which increases the picture resolution beyond the resolution of the previous layer.

Quality variability is also known as signal-to-noise variability. It allows recovery from encoding errors or differences between the original picture and its reconstructed picture. This is obtained using a finite quantizer that encodes the difference picture in the enhancement layer. This additional information increases the overall SNR of the regenerated picture. Quality variable video encoding techniques are often further classified into coarse fine variability and refined fine variability. In coarse fine variability, both coded codes corresponding to one layer (in any two arbitrary access pictures for that layer) are used to correct decoding. Any arrangement of coded bits of a layer can lead to uncontrollable degradation of image quality. There is a coarse fine quality variability method referred to as leaky prediction in which the quality degradation issued by placing coded data from one layer is guaranteed to be reduced. In refined fine variability, the resulting decoding quality is a monotonically increasing function of the number of bits decoded from the highest enhancement layer. That is, each bit that is additionally decoded improves quality. There is also a method that combines coarse and variability to reach intermediate levels in terms of the number of variability steps.

In region of interest variability, the quality or resolution is not uniform in the entire picture region, and certain regions within the picture are improved in the enhancement layer.

Referring to FIG. 3, various further embodiments for transmitting signals in accordance with the present invention will be disclosed. Device 300 obtains content 310. An example of the content may be a video stream. The apparatus includes a service system 302. The service system 302 encodes the content 301 into two separate streams: the low quality stream 303a and the high quality stream 303b. The high quality stream 303b is called a 'add-in' stream because it can be used to, for example, double the bitrate of the low quality stream 303a.

In various further embodiments, the bit rate of low quality stream 303a may be 256 kbps, for example. However, high quality stream 303b is 'add-in' which improves the quality of the combined stream of two streams 303a and 303b. In contrast, the low quality stream 303a may be consumed as a single stream. For example, when the reception is bad.

Referring back to the example of FIG. 3, the apparatus 300 further includes a multiplexer 304a (or IP encapsulation in FIG. 4). The low quality stream 303a is multiplexed into a separate transport stream TS1. TS1 is carried using high priority HP modulation. The high quality stream 303b is multiplexed into a separate transport stream TS2 in the multiplexer 304b (or IPE). TS2 is carried using low priority LP modulation.

With continued reference to FIG. 3, the apparatus 300 also includes a modulator 305. The modulator combines TS1 comprising the high priority stream 303a and TS2 comprising the low priority stream 303b. The modulator 305 includes TS1 and TS2 in one signal 306 and transmits it. The modulator 305 uses layered transmission (or modulation) as defined in ETSI EN 300. In this hierarchical modulation, TS1 is sent in a high priority stream with its own channel coding rate and TS2 is sent in a low priority stream with its own channel coding rate.

In various further embodiments, if the receiving device wants to consume only limited quality streams, the receiving device may filter the HP TS1 stream of the received signal. On the other hand, if the receiving device wants to consume the stream of improved quality or in the case of maximum quality stream, the receiving device uses both HP TS1 and LP TS2.

4 shows a further alternative embodiment of the present invention, in which case a phase shift between TS streams is used. 4 discloses an alternative to various further embodiments, in which case the receiving device cannot simultaneously receive both the HP stream and the LP stream. Thus, Figure 4 offers additional possibilities if the receiver cannot do so. In the embodiment according to FIG. 4, LP and HP streams are transmitted out of phase. A further embodiment of FIG. 4 includes an apparatus 300 further comprising a phase shift control 400. Phase shift control 400 controls the output of IPE1 (first multiprotocol encapsulation) and IPE2 (second multiprotocol encapsulation) so that the TS stream of the LP and the TS stream of HP are not synchronized. In FIG. 4, signal 401 shows the output of IPE 1 including TS1 and signal 402 shows the output of IPE 2 including TS2.

The IP encapsulation unit creates time-slices of the HP stream and the LP stream. The boundaries of the time-division of the LP stream relative to the intended decoding or playback time are within a limited defined range compared to the intended decoding or playback time of the time-division of the HP stream of the same user service. Means for fitting time-division boundaries include slowing and ruining bitrate adaptation with the MPE-FEC frame of the coded bitstream. Bit rate adaptation of the coded bitstream includes, for example, dropping selected pictures from the enhancement layer or removing reference pictures from the end of the set of pictures from the HP stream to the LP stream. Meeting the time-division boundaries of HP and LP streams helps to reduce the expected tune-in delay, i.e. the time from the start of wireless reception to the start of media playback. Furthermore, boundary streams within the HP stream time-division are aligned in terms of the encoding or reproduction time they intended. For example, the timestamps of the first video audio and video samples within the same time-division should be approximately equal.

In a further embodiment of the invention, the IP encapsulation produces a phase shifted transmission of the HP and LP streams of a single user service. In another embodiment of the invention, two IP encapsulation units may be used including phase shifts. That is, bursts of LP and HP streams of the same user service are transmitted next to each other rather than in parallel. The time-division of the LP stream is preferably transmitted before the time-division of the HP stream corresponding to the LP time-division in terms of media decoding or playback time. As a result, if the terminal starts receiving during the HP stream time-division transmission corresponding to the transmission of the LP stream time-division, the HP stream time-division can be decoded and reproduced. If the order of transmission of the time-divisions cycles in a different way and the first time-division is received from the LP stream, then the receiver will not be able to decode the first LP stream time-division, resulting in longer tuning delays.

If the IP encapsulation produces a phase shifted transmission of HP and LP streams of a single user service, it also provides the receiver with the means to correctly adjust the initial buffering delay. One means of adjustment is to provide an initial buffering delay for each transmitted time-divided burst. Another means is to indicate in advance the number and order of transmission of priority classes or to fix them in the specification. As a result, the receiver will need to know how many time-division bursts are still received for a particular period of media decoding and playback time before the decoding starts.

Once reception has begun, the receiver can reconstruct a single media bitstream from the HP and LP streams and buffers enough data to allow the bitstream to enter the media decoder fast enough. The initial buffering delay is signaled every time-divided burst, and then the receiver buffers as recommended in the signaling. Once the number of priority classes and the order of transmission are known, the receiver buffers as long as the last time-division corresponding to the first received interval of media decoding and playback time is received.

The receiver organizes the media samples from the HP stream and LP stream time-divisions into a single bitstream, where the media samples are present according to the decoding order defined in the corresponding media encoding standard. If transmission follows IP multicast, this is typically done using the RTP timestamp of the samples. If media-specific means are used to transmit samples in different time-divisions, an interleaved packetization mode of RTP payload format is used and the payload format provides means for deinterleaving the samples to return them to their decoding order. to provide. For example, if an interleaved packetization mode of H.264 RTP payload format is used, a coding order number (DON) may be derived for each network summary layer (NAL) unit of H.264.

5 illustrates coordination between terminal 500 and receiver 501 when receiving a DVB signal with content encoded according to various additional embodiments of the present invention. Receiver 501 receives a wireless digital wideband signal, such as a DVB-H signal. The user selects the desired service from the electronic service guide (ESG) stored in the terminal in block 503. The receiver selects either a service that consumes all 256kbps or a service that consumes all 512kbps if data in the ESG shows that this possibility is possible. Terminal 500 then generates corresponding filters in block 540. A filter is generated for the IP streams that wish to obtain a service. For example, a service above 512kbps contains at least two IP streams. Therefore at least two filters are needed in such cases.

Receiver 501 executes service discovery for the requested IP streams in block 505. Within block 505 the PID is found via PAT, PMT and INT. Furthermore, discovering the modulation parameters of the LP and HP streams occurs. Finding a modulated parameter depends on the selected service, ie whether it is carried in LP or HP. In addition, modulation parameters for HP and LP streams can be found by, for example, layer bits in the terrestrial delivery system descriptor. At block 506, the receiver 501 coordinates the reception between the HP and LP streams. If a low bitrate service of 256 kbps is selected, the receiver 501 does not need to switch between HP and LP streams because all data is carried in the HP stream.

If a high bitrate service of 512 kbps is selected, the receiver 501 switches between the HP and LP streams, for example after a second burst. The receiver 501 also includes butter management means 507 and receive buffer means 508. The buffer management block 507 controls the buffer resources and transmits the received data to the terminal 500 once the buffer is full.

The terminal 500 includes a streaming assembling controller 508, which checks whether a stream set is needed. The controller 508 checks whether a low bitrate service or a high bitrate service is selected. If a high bitlace service is chosen, it is necessary to gather some. The terminal within block 510 collects the high rate bit rate from the low bit stream and from the enhancement. In one embodiment of the present invention, layered codecs aggregate a low quality stream originating from HP TS and an enhancement stream originating from LP TS into a single stream. At block 509 the stream is consumed. Block 509 provides either a directly received bitrate service or a fast bitlace service collected for consumption. Terminal 500 further includes terminal memory 511 that can be used for aggregation, buffering, and stream consumption.

The terminal may be a mobile handheld terminal that receives a DVB-H signal. There are various ways to implement the receiver device.

Handheld devices

Handheld devices are usually powered by batteries and are becoming a daily companion in our daily wandering activities. Except for some of them, cellular mobile phones will be able to easily enable interactive applications because they return channels. Examples of handheld devices: Cellular mobile telephones that include broadcast receiving capability. PDAs: Generally have the advantage of having a larger screen than a mobile phone, but both devices tend to mix. Portable video game devices: Their main advantage is that the screen is very well prepared for TV applications, for example, it is widespread among young people.

Portable devices

Portable devices are batteries that are powered and move around without having a small screen. For example: flat-battery-powered TV sets: There are several manufacturers that provide such devices, and examples of use are: moving from house to house (from kitchen to bedroom). Portable DVD players, laptop computers and the like are other examples.

In-vehicle Integrated Devices

In-vehicle integrated devices are also available platforms. It is integrated in private cars, taxis, buses and trams. Various screen sizes are expected.

Some embodiments of the invention apply to the system of FIG. 6. The integrated receiver device (IRD) preferably operates below the effective viewing range of the digital broadcast network (DBN). Alternatively, the IRD may be referred to as an end user terminal (EUT). The IRD may receive IP based services provided by the DBN. The DBN is based on DVB, preferably DVB-T, and the transmission of the DBN includes TSs based on hierarchical transmission modulation. The transmission is preferably wireless broadband transmission. The date is processed in the DBN before the transfer. The network DBN of FIG. 6 may be configured to receive service content from a content provider. The service system of the DBN encodes the content into two distinct streams. The first stream (low quality) stream and the second stream (high quality) stream. The high quality stream contains additional information that can be used to increase the overall speed of the combined streams. The propagation relay (HE) of the system multiplexes the streams so that the first stream is multiplexed into a separate TS1 and the second stream is multiplexed into a separate TS2. TS1 multiplexing is performed using HP hierarchical modulation. TS2 multiplexing is performed using LP hierarchical modulation. Modulation of HEs sends TS1 and TS2 to IRD in a single signal.

DBN transmission is a wireless or mobile transmission to DVB-H based IRD. Therefore, data can be transmitted wirelessly.

6, relay units (HEs) including an IP encapsulation unit perform multi-protocol encapsulation (MPE) and convert IP data into a MPEG-TS (Moving Picture Experts Group-Transport Stream) based data container. ) Into. HEs perform the creation of tables, linking tables and modifying tables.

The TSs thus produced are transmitted along the DVB-H data link. IRD digitally receives broadcast data. The IRD receives its descriptor and also receives the TSs according to the TSs with hierarchical broadband transmission and priority. The IRD may identify TSs with a priority indication. Therefore, the DBN signals the priority of TS of hierarchical transmission. The IRD analyzes, for example, the transport_stream_id received from the NIT. The IRD can separate TSs with different priorities. IRDs can also classify TSs based on their hierarchical priority. Therefore, the receiver IRD may use the HP TS1 stream if it wants to consume only a limited quality stream. Now LP TS2 is not consumed at all. In addition, the receiver IRD may use HP TS1 streams and LP TS2 streams if they want to consume a better quality stream, thereby having a higher bitrate for the service consumed.

Although the foregoing description includes many specific examples, this is intended to explain the invention and should not be constructed to limit the scope of the invention. Many examples may be combined in various ways in single or multiple embodiments. Therefore, it will be apparent to those skilled in the art that various modifications and variations can be made in the apparatus and the process without departing from the spirit and spirit of the invention.

Claims (13)

An apparatus for transmitting a digital broadcast signal using hierarchical modulation comprising a high priority stream and a low priority stream, The device, One or more encoders for encoding service content transmitted in two streams, A first stream is configured to be sent with the higher priority stream, and And a second stream transmitted with the lower priority stream is configured to include additional information for increasing the bit rate of the first stream. The method of claim 1, The first stream comprises a low quality stream and the second stream comprises a high quality stream such that the combination of the first stream and the second stream provides increased bitrate for the service content. Device for transmitting signals. The method of claim 1, And the first stream and the second stream comprise the same service stream. The method of claim 1, Wherein the first stream is a base layer containing low resolution video. The method of claim 1, And the second stream includes an enhancement layer that includes side information for high resolution video. The method according to claim 1 or 2, Wherein the first and second streams are configured to be transmitted with a phase shift between the first and second streams. The method of claim 1, And the digital broadcast signal comprises a mobile digital broadband broadcast signal such as DVB-H. An apparatus for receiving a digital broadcast signal using hierarchical modulation comprising a high priority stream and a low priority stream, The device, One or more decoders for decoding service content received in two streams, A first stream is configured to be received with the higher priority stream, and And a second stream received with the lower priority stream is configured to include additional information for increasing the bitrate of the first stream. The method of claim 8, And the device comprises a mobile receiver for receiving DVB-H transmissions. A method of transmitting a digital broadcast signal using hierarchical modulation comprising a high priority stream and a low priority stream, The method, Encoding content transmitted in two streams, A first stream is configured to be sent with the higher priority stream, and And a second stream sent with the lower priority stream is configured to include side information for increasing the bitrate of the first stream. A method of receiving a digital broadcast signal using hierarchical modulation comprising a high priority stream and a low priority stream, The method, Decoding content received in two streams, A first stream is configured to be received with the higher priority stream, and And a second stream received with the lower priority stream is configured to include additional information for increasing the bit rate of the first stream. An encoder for encoding a digital broadcast signal using hierarchical modulation comprising a high priority stream and a low priority stream. The encoder, Encoding means for encoding service content transmitted in two streams, A first stream is configured to be sent with the higher priority stream, and And a second stream transmitted with the lower priority stream is configured to include side information for increasing the bitrate of the first stream. A mobile terminal configured to process data packets transmitted as one or more transport stream packets including packet identifiers, the method comprising: The terminal, A first memory for storing electronic service guide information; A second memory for storing service discovery data linking service discovery data between lower and upper priority streams; Means for selecting a service from the electronic service guide for rendering; And A transport stream filter for filtering at least the service discovery data using a packet identifier; And said filtering is based on selecting between a low priority stream and a high priority stream for receiving and rendering a service.

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