CN102957498A - Method and device for transmitting layered service streams and method and device for receiving layered service streams - Google Patents

Abstract

The invention discloses a method and device for sending and receiving a layered service flow, comprising: respectively performing scrambling and forward error correction coding on a multi-layer data flow, and obtaining a plurality of coding bits corresponding to the multi-layer data flow Stream, the priority of the multi-layer data stream is different; perform bit interleaving and constellation mapping on the multiple coded bit streams, and obtain multiple modulation symbols correspondingly; multiplex the multiple modulation symbols in the same power loading mode In a constellation space, obtain layered modulation symbols; send the layered modulation symbols; the method and device for sending and receiving layered service streams of the present invention improve the space spectrum utilization rate of the broadcasting system without significantly reducing the basic quality of service Under the premise of providing users with as much program content as possible, it solves the problem of coexistence of service popularization and service differentiation in the digital audio broadcasting system.

Description

Method and device for sending and receiving layered service flow

technical field

The present invention relates to a signal sending and receiving method and device, in particular to a method and device for sending and receiving layered service streams in a digital audio broadcasting system.

Background technique

In hierarchical modulation, the source data stream is first divided into several layers, and each layer is mapped to different layers of the signal constellation diagram according to different priorities. Different layers of the constellation map correspond to different receiving sensitivities due to different minimum distances between symbols. Therefore, on the receiving side, receivers with better receiving conditions can demodulate the source data of multiple layers to obtain better service quality. , while poorer receivers are only able to decode data from fewer layers, even just the base layer. Hierarchical modulation has been widely used in multimedia broadcasting and communication standards such as DVB-T, MediaFLO and UMB.

However, in the digital audio broadcasting system, it is also necessary to consider the combination of the layered modulation supported by the physical layer and the layered coding of the DRA source code, so as to properly realize the automatic upgrade/downgrade of the service and ensure that the user is in a bad channel environment. Basic service requirements and audio quality can be guaranteed, and additional high-level bit information can be demodulated when the channel environment is good to achieve enhanced services and improved audio effects.

Contents of the invention

The purpose of the present invention is to provide a method and device for sending and receiving layered service flows.

One aspect of the present invention provides a method for sending a layered service flow, including:

Performing scrambling and forward error correction coding on the multi-layer data streams respectively to obtain multiple coded bit streams corresponding to the multi-layer data streams, the multi-layer data streams have different priorities;

performing bit interleaving and constellation mapping on the plurality of coded bit streams, correspondingly obtaining a plurality of modulation symbols;

Multiplexing the multiple modulation symbols in the same constellation space according to a power loading manner to obtain hierarchical modulation symbols;

The layered modulation symbols are transmitted.

Another aspect of the present invention provides a method for receiving a layered service flow, including:

Extract the load symbol according to the system frame structure and the specified position of the spectrum template, and generate the modulated signal existing in the constellation space;

Demodulating the first-layer symbols in the modulated signal to obtain the first-layer demodulated symbols;

Deinterleaving and decoding the demodulated symbols of the first layer to obtain decoded bits of the first layer;

Performing bit descrambling on the decoded bits of the first layer to obtain the service data stream of the first layer.

Another aspect of the present invention provides a device for sending a layered service flow, including:

A pseudo-random sequence scrambler, configured to scramble the multi-layer data streams to obtain multiple information bit streams corresponding to the multi-layer data streams;

A forward error correction encoder, configured to search for a corresponding encoded codeword in the codeword set according to the plurality of information bit streams output by the pseudo-random sequence scrambler, and correspondingly generate a plurality of encoded bit streams;

An interleaver, configured to reorder the multiple coded bit streams output by the forward error correction encoder according to predetermined rules, and correspondingly obtain multiple interleaved bit streams;

a mapper, configured to map the multiple interleaved bit streams output by the interleaver, and correspondingly obtain multiple modulation symbols;

a multiplexer, configured to multiplex the plurality of modulation symbols output by the mapper in the same constellation space according to a power loading manner, to obtain hierarchical modulation symbols;

a transmitter, configured to transmit the layered modulation symbols output by the multiplexer.

Another aspect of the present invention provides a device for receiving a layered service flow, including:

The signal detector is used to extract the load symbol according to the position specified by the system frame structure and the frequency template, and generate the modulated signal existing in the constellation space;

a layered demapper, configured to demodulate first-layer symbols in the modulated signal output by the signal detector, to obtain first-layer demodulated symbols;

A deinterleaver, configured to deinterleave the first layer demodulation symbols output by the layered demapper to obtain a first layer deinterleaved bit stream;

A forward error correction decoder, configured to search for maximum likelihood probability or maximum a posteriori probability decoding in a message passing manner according to the first-layer deinterleaved bit stream output by the de-interleaver, and obtain the first-layer decoded bits flow;

A descrambler, configured to descramble the first-layer decoded bit stream output by the FEC decoder, to obtain first-layer service data.

The method and device for sending and receiving layered service flows of the present invention. Has the following advantages:

The invention effectively improves the space spectrum utilization rate of the broadcasting system, provides users with as much program content as possible without significantly reducing the basic service quality, and solves the problem of coexistence of service popularization and service differentiation in the digital audio broadcasting system question. The invention can be widely used in various digital audio broadcasting fields such as satellite audio broadcasting, terrestrial wireless audio broadcasting, terrestrial handheld audio broadcasting and the like.

Description of drawings

The above and/or additional aspects and advantages of the present invention will become apparent and easy to understand from the following description of the embodiments in conjunction with the accompanying drawings, wherein:

Fig. 1 is a data processing flowchart of a method for sending a layered service flow provided by an embodiment of the present invention;

Fig. 2a is a system frame structure based on the method and device for sending and receiving a layered service flow provided by an embodiment of the present invention;

FIG. 2b is a subframe structure diagram based on the method and device for sending and receiving a hierarchical service flow provided by an embodiment of the present invention;

Fig. 3 is a flow chart of a method for sending a layered service flow provided by an embodiment of the present invention;

Fig. 4 is the linear feedback shift register that produces scrambling code;

FIG. 5 is a schematic diagram of layered modulation provided by an embodiment of the present invention;

Figure 6 is a hierarchical 16QAM constellation map, α ₁ =2, α ₁ =1;

Figure 7 is a hierarchical 16QAM constellation map, α ₁ =3, α ₂ =1;

Figure 8 is a hierarchical 16QAM constellation map, α ₁ =5, α ₂ =1;

Figure 9 is a hierarchical 64QAM constellation map, α ₁ =4, α ₂ =1;

Figure 10 is a hierarchical 64QAM constellation map, α ₁ =5, α ₂ =1;

Figure 11 is a hierarchical 64QAM constellation map, α ₁ =7, α ₂ =1;

FIG. 12 is a flowchart of a method for receiving a layered service flow provided by an embodiment of the present invention;

Fig. 13 is a schematic diagram of a device for sending a layered service flow according to an embodiment of the present invention;

Fig. 14 is a schematic diagram of a device for receiving a layered service flow provided by an embodiment of the present invention;

Fig. 15 is a schematic diagram of a device for receiving a layered service flow according to another embodiment of the present invention;

Fig. 16 is a schematic diagram of a device for receiving a layered service flow provided by another embodiment of the present invention.

Detailed ways

Preferred embodiments of the method and device for sending and receiving layered service flows of the present invention will be described in detail below in conjunction with the accompanying drawings.

Please refer to FIG. 1 and FIG. 2. FIG. 1 is a processing flowchart of a method for sending a hierarchical service flow provided by an embodiment of the present invention, and FIG. 2a is a flow chart of the method and device for sending and receiving a hierarchical service flow provided by an embodiment of the present invention Based on the frame structure of the system, FIG. 2b is a subframe structure diagram based on the method and device for sending and receiving the layered service flow provided by the embodiment of the present invention.

The layered service stream sending and receiving method and device provided by the embodiment of the present invention are based on a coded Orthogonal Frequency Division Multiplexing (Ccoded Orthogonal Frequency Division Multiplexing, COFDM) digital audio broadcasting system, the system frame structure consists of superframe, frame, sub Frames and OFDM symbols consist of 4 layers.

In transmission mode 1, each superframe is divided into 4 frames, each frame is divided into 4 subframes, each subframe is divided into 57 OFDM symbols, and each symbol has a total of 242 effective carriers. The first OFDM symbol of each subframe is used as a beacon for system synchronization and demodulation preprocessing, and the other 56 OFDM symbols include load, scattered pilot, continuous pilot and virtual subcarrier.

In transmission mode 2, each superframe is divided into 4 frames, each frame is divided into 4 subframes, each subframe is divided into 112 OFDM symbols, and each symbol has a total of 122 effective carriers. The first OFDM symbol of each subframe is used as a beacon, and the other 111 OFDM symbols contain loads, scattered pilots, continuous pilots, and virtual subcarriers.

In transmission mode 3, each superframe is divided into 4 frames, each frame is divided into 4 subframes, each subframe is divided into 62 OFDM symbols, and each symbol has a total of 242 effective carriers. Among them, the first OFDM symbol of each subframe is used as a beacon, and the other 61 OFDM symbols include load, scattered pilot, continuous pilot and virtual subcarrier. Each OFDM symbol is prefixed by a guard interval to reduce inter-OFDM symbol interference. The subcarrier spacing of transmission mode 1 and transmission mode 3 are the same, but the length of the guard interval is different, and the subcarrier spacing of transmission mode 2 is twice that of the previous two modes. Define the unit time T=1/816000 second, and system parameters such as subcarrier interval, symbol interval, and user interval are shown in Table 1:

Table 1: Transmission Mode System Parameters

where T = 1/816000 second.

The OFDM signal consists of up to 8 subbands with a nominal bandwidth of 100kHz. Spectrum mode specifies the number of subbands, and the location of effective subbands and virtual subbands. In the partial spectrum mode, all subcarriers in the upper half subband or the lower half subband of some effective subbands are virtual subcarriers. In an effective subband, each OFDM symbol contains N _v effective subcarriers composed of continuous pilots, scattered pilots and data subcarriers (when the subcarriers of the upper and lower half subbands are not all virtual subcarriers), or N _v /2 effective subcarriers consisting of continuous pilots, scattered pilots and data subcarriers (when the subcarriers in the upper half or lower half subbands are all virtual subcarriers). For each spectrum mode, the subcarriers in the OFDM symbol except the virtual subcarriers, continuous pilot subcarriers and scattered pilot subcarriers are data subcarriers, and the data subcarriers place service description information symbols and service data symbols.

The superframe length is 2560ms, each superframe consists of 4 physical layer signal frames with a length of 640ms, each physical layer signal frame includes 4 subframes with a length of 160ms, and each subframe includes 1 beacon and _SN OFDM symbols. Each physical layer signal frame carries data of one logical frame. See Figure 1 for the logical frame structure and physical layer signal frame structure, and Figure 2 for the subframe structure.

Please refer to FIG. 3 . FIG. 3 is a flowchart of a method for sending a layered service flow according to an embodiment of the present invention. The method comprises the steps of:

Step S11, perform scrambling and forward error correction coding on the multi-layer data streams respectively, and obtain multiple coded bit streams corresponding to the multi-layer data streams, and the multi-layer data streams have different priorities.

In an implementation manner of this embodiment, the data streams of each layer (input data byte streams are MSB-first) are respectively scrambled by a binary pseudo-random sequence P _c (i). P _c (i) is generated by a linear feedback shift register, as shown in Figure 4, and its corresponding generator polynomial is: x ¹² +x ¹¹ +x ⁸ +x ⁶ +1. The initial value of the shift register is 000000000001, and the linear feedback shift register is reset at the beginning of each logic frame.

The scrambling code is realized by modulo 2 addition of the input bit information sequence and the binary pseudo-random sequence, see formula (1):

$\mathrm{<span\; class="notranslate">\; Y</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&CirclePlus;</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

In the formula:

X(i)__information bits before scrambling

Y(i)__scrambled bits

The scrambled data is encoded by LDPC forward error correction code to obtain the coded bit stream, the codeword length is 9216 bits, and its encoding configuration is shown in Table 2.

Table 2: LDPC encoding configuration

The output code word c of LDPC is composed of input information bits m={m ₀ , m ₁ , L, m _k-1 } and parity bits p={p ₀ , p ₁ ,...,p _9215-K } {c ₀ , c ₁ , L, c ₉₂₁₅ }={m ₀ , m ₁ , L m _k-1 , p ₀ , p ₁ , L p _9215-k }, where parity bit

p={p ₀ , p ₁ ,..., p _9215-K } is obtained by solving the following equation from the parity check matrix H:

H×c ^T ＝0 (2)

In the formula:

0 - (9216-K) row 1 column vector of all 0 columns

H——LDPC parity check matrix.

Step S12 , performing bit interleaving and constellation mapping on the multiple coded bit streams to obtain multiple modulation symbols correspondingly.

In an implementation manner of this embodiment, the coded bit stream is reordered according to a predetermined rule, and an interleaved bit stream is correspondingly obtained.

The interleaved bit streams of each layer of business are mapped to constellations in the form of QPSK and 16QAM. Figure 5 shows the two-layer priority layered modulation based on 16QAM. 16QAM can carry 4 information bits, and the left two bits (MSB) actually represent a QPSK constellation diagram. Its constellation point distance is greater than that of 16QAM, which has better protection for information, so the first two bits are used to Carries high-priority data, for example, FM audio-quality data streams. And use the last two bits to load low-priority data, for example, CD-quality data streams. In this way, users with good reception conditions can receive services with CD sound quality, while users with poor reception conditions can only receive broadcasts with FM sound quality.

Step S13. Multiplexing the multiple modulation symbols in the same constellation space according to the power loading method to obtain hierarchical modulation symbols.

In an implementation manner of this embodiment, after each layer is independently modulated, the multiplexer multiplexes these symbols in a constellation space according to the power loading manner of each layer. Generally, data streams with high priority need to correspond to high power values, and data streams with low priority should correspond to low power values.

Figure 6, Figure 7 and Figure 8 show the layered modulation results after two-layer QPSK modulation. In FIG. 6 , the amplitude gain of the high priority is α ₁ =2, and the amplitude gain of the low priority is α ₂ =1. At this time, the layered modulation is equivalent to the traditional 16QAM modulation. Fig. 7 and Fig. 8 show constellation diagrams of two power allocation modes of α ₁ =3, α ₂ =1 and α ₁ =5, α ₂ =1.

Figure 9, Figure 10 and Figure 11 show the hierarchical modulation constellations of one channel of QPSK and one channel of 16QAM. In Figure 9, the constellation corresponding to α ₁ =4, α ₂ =1 is the same as the traditional 64QAM, and Figure 10 and Figure 11 show α ₁ =5, α ₂ =1 and α ₁ =5, α ₂ =1 Two situations. Compared with the aforementioned two-way QPSK multiplexing, the amount of data on the second layer is larger at this time, but the reliability is worse. Only when the user is in a very good receiving position can it be possible to decode the low-priority 16QAM signal. It is worth noting that the 16QAM with low priority can also be obtained by multiplexing two QPSK channels, so a 3-layer hierarchical modulation method is obtained.

α ₁ and α ₂ can also be simplified as a parameter α, which is defined as the ratio between the minimum distance of the constellation points carrying high-priority bits and the minimum distance of constellation points carrying low-priority bits. In 16QAM, α=(α ₁ -1)/α ₂ , and in 64QAM, α=(α ₁ -3)/α ₂ . For example, Fig. 6, Fig. 7 and Fig. 8 respectively correspond to the 16QAM constellation diagram of α=1, α=2 and α=4; Fig. 9, Fig. 10 and Fig. 11 respectively correspond to α=1, α=2 and α= 4 64QAM constellation diagram.

Step S14, sending the layered modulation symbols.

In an implementation manner of this embodiment, step S14 specifically includes:

According to the system frame structure, the layered modulation symbols are multiplexed with scattered pilots and continuous pilots to obtain frequency domain signals of an orthogonal multiplexing structure;

Using frequency-time domain transformation, converting the frequency domain signal into time domain samples after frequency-time domain transformation;

The time domain samples are sent in the time domain.

Please refer to FIG. 12 . FIG. 11 is a flow chart of a method for receiving a layered service flow provided by an embodiment of the present invention. The method comprises the steps of:

Step S21, extracting the load symbol according to the system frame structure and the specified position of the spectrum template, and generating a modulated signal existing in the constellation space;

Step S22, demodulating the first-layer symbols in the modulated signal to obtain the first-layer demodulated symbols;

Step S23, deinterleaving and decoding the demodulated symbols of the first layer to obtain decoded bits of the first layer;

Step S24, performing bit descrambling on the decoded bits of the first layer to obtain the first layer service data stream.

Step S25, modulating the demodulated signal of the first layer, or encoding and modulating the decoded bits of the first layer, to obtain a reconstructed first layer modulation symbol;

Step S26, subtracting the reconstructed first layer modulation symbols from the modulation symbols to obtain modulation symbols of other layers;

Step S27, demodulating the second-layer symbols in the modulation symbols of the other layers to obtain the second-layer demodulation symbols;

Step S28, deinterleaving and decoding the demodulated symbols of the second layer to obtain decoded bits of the second layer;

Step S29 , performing bit descrambling on the second layer decoded bits to obtain a second layer service data stream.

In this embodiment, the high-priority symbols are detected first, and the low-priority symbols are regarded as interference at this time. Therefore, the higher the power value corresponding to the high-priority, the higher the signal-to-noise ratio during demodulation. The bit error rate performance of a layer will be better. After the first layer signal is detected, on the one hand, the service data flow of this layer is obtained through deinterleaving, decoding and descrambling. On the other hand, the demodulated symbols are re-modulated and fed back to the front-end, and the impact of the first layer is subtracted from the received symbols. So far, assuming that the feedback signal of the first layer is completely correct, this assumption can be approximated by the feedback of decoded symbols, then the symbols of the second layer will not be interfered by the first layer, and more accurate decoded symbols will be formed. However, since the total power requires normalization, when the power allocation value of the first layer is higher, the power allocation value of the second layer will be less, so the bit error rate performance of the second layer will be worse. That is to say, the greater the difference between the power values of the two layers, the greater the difference between the service quality of the service flows of the two layers. When the user is in a position with poor receiving conditions, only the first layer of data stream can be solved; when the user is in a position with good receiving conditions, the second layer of data can be solved on the basis of solving the first layer to improve Spectrum utilization, better service content and service quality.

Please refer to FIG. 13 . FIG. 13 is a schematic diagram of an apparatus for sending a layered service flow according to an embodiment of the present invention. The device 120 includes:

A pseudo-random sequence scrambler 121, configured to scramble the multi-layer data streams to obtain multiple information bit streams corresponding to the multi-layer data streams;

A forward error correction (FEC) encoder 122, configured to search for a corresponding encoded codeword in the codeword set according to the plurality of information bit streams output by the pseudo-random sequence scrambler, and correspondingly generate a plurality of encoded bits flow;

The interleaver 123 is configured to reorder the multiple coded bit streams output by the forward error correction encoder according to predetermined rules, and correspondingly obtain multiple interleaved bit streams;

A mapper 124, configured to map the multiple interleaved bit streams output by the interleaver, and correspondingly obtain multiple modulation symbols;

A multiplexer 125, configured to multiplex the plurality of modulation symbols output by the mapper in the same constellation space according to a power loading manner, to obtain hierarchical modulation symbols;

The transmitter 126 is configured to send the layered modulation symbols output by the multiplexer.

In an implementation manner of this embodiment, in the multi-layer data flow, the first layer is a high-priority data flow, and the other layers are low-priority data flows.

In another implementation manner of this embodiment, the transmitter 126 includes:

a frequency domain signal generator, configured to multiplex the layered modulation symbols output by the multiplexer with scattered pilots and continuous pilots, to obtain frequency domain signals of an orthogonal multiplexing structure;

A frequency-time domain converter, configured to convert the frequency-domain signal output by the frequency-domain signal generator to obtain time-domain samples after frequency-time domain conversion.

In yet another implementation of this embodiment, the encoding method of the forward error correction coding is a cyclic code, a convolutional code, or an LDPC code; the method of interleaving is a bit-level interleaving method; the method of mapping It is BPSK, QPSK or 16QAM.

Please refer to FIG. 14 , which is a schematic diagram of an apparatus for receiving a layered service flow provided by an embodiment of the present invention. The device 130 includes:

The signal detector 131 is used to extract the load symbol according to the system frame structure and the specified position of the frequency template, and generate the modulated signal existing in the constellation space;

a layered demapper 132, configured to demodulate the first-layer symbols in the modulated signal output by the signal detector 131, to obtain the first-layer demodulated symbols;

A deinterleaver 133, configured to deinterleave the first layer demodulation symbols output by the layered demapper 132 to obtain a first layer deinterleaved bit stream;

The forward error correction decoder 134 is used to search for the maximum likelihood probability or the maximum a posteriori probability decoding in a message passing manner according to the first layer deinterleaved bit stream output by the deinterleaver 133, and obtain the first layer decode the bitstream;

The descrambler 135 is configured to descramble the first-layer decoded bit stream output by the forward error correction decoder 134 to obtain first-layer service data.

Please refer to FIG. 15 , which is a schematic diagram of an apparatus for receiving a layered service flow according to another embodiment of the present invention. The difference between this embodiment and the embodiment corresponding to FIG. 14 is that the device 130 further includes:

a mapper 142, configured to modulate the first-layer demodulated signal output by the layered demapper 132, to obtain reconstructed first-layer modulation symbols;

A subtracter 141, configured to subtract the reconstructed first-layer modulation symbols fed back by the mapper 142 from the modulation symbols output by the signal detector 131, to obtain modulation symbols of other layers;

a layered demapper 152, configured to demodulate the second layer symbols in the modulation symbols of the other layers output by the subtracter 141, to obtain second layer demodulation symbols;

A deinterleaver 153, configured to deinterleave the second layer demodulation symbols output by the layered demapper 152, to obtain a second layer deinterleaved bit stream;

The forward error correction decoder 154 is used to search for the maximum likelihood probability or the maximum a posteriori probability decoding in a message passing manner according to the second layer deinterleaving bit stream output by the deinterleaver 153, and obtain the second layer decode the bitstream;

The descrambler 155 is configured to descramble the layer-2 decoded bit stream output by the forward error correction decoder 154 to obtain layer-2 service data.

Please refer to FIG. 16 . FIG. 16 is a schematic diagram of a device for receiving a layered service flow according to another embodiment of the present invention. The difference between this embodiment and the embodiment corresponding to FIG. 14 is that the device 130 further includes:

An encoder 144, configured to encode the first-layer decoded bit stream output by the forward error correction decoder 134, to obtain a reconstructed first-layer encoded bit stream;

The interleaver 143 is configured to interleave the reconstructed first-layer coded bit stream output by the encoder 144 to obtain a reconstructed first-layer interleaved bit stream;

A mapper 142, configured to map the reconstructed first-layer interleaved bit stream constellation output by the interleaver 143 to obtain reconstructed first-layer modulation symbols;

A subtracter 141, configured to subtract the reconstructed first-layer modulation symbols fed back by the mapper 142 from the modulation symbols output by the signal detector 131, to obtain modulation symbols of other layers;

The layered demapper 152 is further configured to demodulate the second layer symbols in the modulation symbols of the other layers output by the subtracter 141, to obtain the second layer demodulation symbols;

A deinterleaver 153, configured to deinterleave the second layer demodulation symbols output by the layered demapper 152, to obtain a second layer deinterleaved bit stream;

The forward error correction decoder 154 is used to search for the maximum likelihood probability or the maximum a posteriori probability decoding in a message passing manner according to the second layer deinterleaving bit stream output by the deinterleaver 153, and obtain the second layer decode the bitstream;

The descrambler 155 is configured to descramble the layer-2 decoded bit stream output by the forward error correction decoder 154 to obtain layer-2 service data.

In an implementation of this embodiment, the first-level symbols in the load symbols correspond to high-priority data streams, and the other layer symbols correspond to low-priority data streams

It should be understood that due to the similarity of functions, the layered demappers 132 and 152 can be a layered demapper, the deinterleavers 133 and 153 can be a deinterleaver, and the forward error correction decoders 134 and 154 can be A FEC decoder, the descramblers 135 and 155 can be a descrambler.

The method and device for sending and receiving hierarchical service flows proposed by the invention. Has the following advantages:

Aiming at the different channel fading characteristics of different users in the digital audio broadcasting system, a method for transmitting layered service streams and sending and receiving devices is proposed, which effectively improves the space spectrum utilization rate of the broadcasting system, without significantly reducing the basic service Provide users with as much program content as possible under the premise of quality, and solve the problem of coexistence of service popularization and service differentiation in the digital audio broadcasting system. The invention can be widely used in various digital audio broadcasting fields such as satellite audio broadcasting, terrestrial wireless audio broadcasting, terrestrial handheld audio broadcasting and the like.

Those of ordinary skill in the art can understand that all or part of the steps carried by the methods of the above embodiments can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium. During execution, one or a combination of the steps of the method embodiments is included.

In addition, each functional unit in each embodiment of the present invention may be integrated into one processing module, each unit may exist separately physically, or two or more units may be integrated into one module. The above-mentioned integrated modules can be implemented in the form of hardware or in the form of software function modules. If the integrated modules are realized in the form of software function modules and sold or used as independent products, they can also be stored in a computer-readable storage medium.

The storage medium mentioned above may be a read-only memory, a magnetic disk or an optical disk, and the like.

The above is only a preferred embodiment of the present invention, it should be pointed out that, for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.

Claims (16)

1. the sending method of a layering Business Stream is characterized in that, comprising:

The multi-layer data flow point is not carried out scrambler and forward error correction coding, obtain a plurality of coded bit streams corresponding with described multi-layer data stream, the priority of described multi-layer data stream is different;

Described a plurality of coded bit streams are interweaved and constellation mapping a plurality of modulation symbols of corresponding acquisition;

Described a plurality of modulation symbols are multiplexing in same constellation space according to the power load mode, obtain the hierarchical modulation symbol;

Send described hierarchical modulation symbol.

2. method according to claim 1 is characterized in that, in described multi-layer data stream, ground floor is the data flow of high priority, and other layers are the data flow of low priority.

3. method according to claim 1 is characterized in that, the described hierarchical modulation symbol of described transmission specifically comprises:

According to system frame structure, with described hierarchical modulation symbol and scattered pilot and continuous pilot multiple connection, obtain the frequency-region signal of orthogonal multiplex structure;

Utilize the conversion of frequency-time domain, described frequency-region signal is converted into time-domain sampling after overfrequency-time domain conversion;

Send described time-domain sampling in time domain.

4. method according to claim 1 is characterized in that,

The coded system of described forward error correction coding is cyclic code, convolution code or LDPC code;

The described method that interweaves is the bit-level deinterleaving method;

The method of described mapping is BPSK, QPSK or 16QAM.

5. the method for reseptance of a layering Business Stream is characterized in that, comprising:

Extract the load symbol according to system frame structure and spectrum mask assigned position, generate the modulation signal that is present in the constellation space;

Ground floor symbol in the described modulation signal is carried out demodulation, obtain the ground floor demodulation symbol;

Described ground floor demodulation symbol is carried out deinterleaving and decoding, obtain the ground floor decoded bits;

Described ground floor decoded bits is carried out bit descrambling, obtain the ground floor business data flow.

6. method according to claim 5 is characterized in that, described method also comprises:

With described ground floor restituted signal modulation, perhaps with described ground floor decoded bits coding and modulation, obtain the ground floor modulation symbol of rebuilding;

In described modulation symbol, deduct the ground floor modulation symbol of described reconstruction, obtain the modulation symbol of other layers;

Second layer symbol in the modulation symbol of described other layers is carried out demodulation, obtain second layer demodulation symbol;

Described second layer demodulation symbol is carried out deinterleaving and decoding, obtain second layer decoded bits;

Described second layer decoded bits is carried out bit descrambling, obtain second layer business data flow.

7. method according to claim 6 is characterized in that, described method also comprises: the data flow of the corresponding high priority of the ground floor symbol in the described load symbol, the data flow of the corresponding low priority of described other layers symbol.

8. the described method of any one in 7 according to claim 5 is characterized in that,

With the deversity scheme that comprises frequency diversity and time domain diversity input is carried out in load;

The method of described demodulation is the demodulating algorithm that comprises demodulation feedback or decoding feedback.

9. the dispensing device of a layering Business Stream is characterized in that, comprising:

The pseudo random sequence scrambler is used for the multi-layer data flow point is not carried out scrambler, obtains a plurality of message bit streams corresponding with described multi-layer data stream;

Forward error correction coder is used for the described a plurality of message bit streams according to described pseudo random sequence scrambler output, searches out coding codeword corresponding in the codeword set, a plurality of coded bit streams of corresponding generation;

Interleaver is used for according to a plurality of coded bit stream rearrangements of pre-defined rule to described forward error correction coder output, a plurality of interleaved bitstreams of corresponding acquisition;

Mapper is used for described a plurality of interleaved bitstreams of described interleaver output are shone upon a plurality of modulation symbols of corresponding acquisition;

Multiplexer for described a plurality of modulation symbols of described mapper output are multiplexing in same constellation space according to the power load mode, obtains the hierarchical modulation symbol;

Transmitter is used for sending the described hierarchical modulation symbol that described multiplexer is exported.

10. device according to claim 9 is characterized in that, in described multi-layer data stream, ground floor is the data flow of high priority, and other layers are the data flow of low priority.

11. device according to claim 9 is characterized in that, described transmitter comprises:

The frequency-region signal maker is used for described hierarchical modulation symbol and scattered pilot and continuous pilot multiple connection with described multiplexer output, obtains the frequency-region signal of orthogonal multiplex structure;

Frequently-and the time domain converter, be used for the described frequency-region signal of described frequency-region signal maker output is obtained time-domain sampling after overfrequency-time domain conversion.

12. device according to claim 9 is characterized in that,

The coded system of described forward error correction coding is cyclic code, convolution code or LDPC code;

The described method that interweaves is the bit-level deinterleaving method;

The method of described mapping is BPSK, QPSK or 16QAM.

13. the receiving system of a layering Business Stream is characterized in that, comprising:

Signal detector is used for extracting the load symbol according to system frame structure and frequency templates assigned position, generates the modulation signal that is present in the constellation space;

The layering de-mapping device is used for the ground floor symbol of the described modulation signal of described signal detector output is carried out demodulation, obtains the ground floor demodulation symbol;

Deinterleaver is used for the described ground floor demodulation symbol of described layering de-mapping device output is carried out deinterleaving, obtains ground floor deinterleaving bit stream;

Forward error correction decoder is used for the described ground floor deinterleaving bit stream according to described deinterleaver output, searches out maximum likelihood probability or maximum a posteriori probability decoding with the message transfer mode, obtains the ground floor decoding bit stream;

Descrambler is used for the described ground floor decoding bit stream descrambling to described forward error correction decoder output, obtains the ground floor business datum.

14. device according to claim 13 is characterized in that, described device also comprises:

Mapper is used for the described ground floor restituted signal modulation with described layering de-mapping device output, obtains the ground floor modulation symbol of rebuilding; With

Subtracter is used for deducting at the described modulation symbol of described signal detector output the ground floor modulation symbol of the described reconstruction of described mapper feedback, obtains the modulation symbol of other layers;

Described layering de-mapping device also is used for the second layer symbol of the modulation symbol of described other layers of described subtracter output is carried out demodulation, obtains second layer demodulation symbol;

Described deinterleaver also is used for the described second layer demodulation symbol of described layering de-mapping device output is carried out deinterleaving, obtains second layer deinterleaving bit stream;

Described forward error correction decoder also is used for the described second layer deinterleaving bit stream according to described deinterleaver output, searches out maximum likelihood probability or maximum a posteriori probability decoding with the message transfer mode, obtains second layer decoding bit stream;

Described descrambler also is used for the described second layer decoding bit stream descrambling to described forward error correction decoder output, obtains second layer business datum.

15. device according to claim 13 is characterized in that, described device also comprises:

Encoder is used for the ground floor decoding bit stream of described forward error correction decoder output is encoded, and obtains the ground floor coded bit stream of rebuilding;

Interleaver is used for the ground floor coded bit stream of the reconstruction of described encoder output is interweaved, and obtains the ground floor interleaved bitstream of rebuilding;

Mapper is used for the ground floor interleaved bitstream constellation mapping with the described reconstruction of described interleaver output, obtains the ground floor modulation symbol of rebuilding; With

Subtracter is used for deducting at the described modulation symbol of described signal detector output the ground floor modulation symbol of the described reconstruction of described mapper feedback, obtains the modulation symbol of other layers;

Described layering de-mapping device also is used for the second layer symbol of the modulation symbol of described other layers of described subtracter output is carried out demodulation, obtains second layer demodulation symbol;

Described deinterleaver is used for the described second layer demodulation symbol of described layering de-mapping device output is carried out deinterleaving, obtains second layer deinterleaving bit stream;

Described forward error correction decoder is used for the described second layer deinterleaving bit stream according to described deinterleaver output, searches out maximum likelihood probability or maximum a posteriori probability decoding with the message transfer mode, obtains second layer decoding bit stream;

Described descrambler is used for the described second layer decoding bit stream descrambling to described forward error correction decoder output, obtains second layer business datum.

16. device according to claim 13 is characterized in that, the data flow of the corresponding high priority of the ground floor symbol in the described load symbol, the data flow of the corresponding low priority of described other layers symbol.

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