HK1106891A - Dab capatible terrestrial mobile multimedia broadcast transmission and receiving method and system - Google Patents

Description

DAB compatible ground mobile multimedia broadcast receiving and transmitting method and system

Technical Field

The present invention relates to the technical field of Digital information transmission, particularly to a method and a system for transmitting and receiving a terrestrial mobile multimedia broadcast (T-MMB) compatible with Digital Audio Broadcasting (DAB).

Background

Digital multimedia broadcasting refers to a multimedia broadcasting mode for a handheld terminal, and currently, digital multimedia broadcasting standards which are much concerned in the industry are the european standard DVB-H, the U.S. MediaFLO and the korean standard T-DMB.

T-DMB, known as Digital Multimedia Broadcasting (DAB), was developed based on DAB. DAB digital broadcasting was developed by a consortium of 12 members, known as EUREKA-147, and the system was originally named Digital Audio Broadcasting (DAB) and has been used as a standard for distinguishing real DAB broadcasting from other digital audio broadcasting. In 1994, Eureka-147 was selected by the international organization for standardization (ISO) as the international standard for digital audio broadcasting. Today, most of the world is testing either digital broadcasting that already implements this standard. Europe Eury-147 DAB standard: in 9 months 1988, the euro has first conducted experiments on eureka-147 DAB at the world radio administration, the eureka-147 DAB system was standardized in 1995, which is a typical DAB system, and has been developed to a considerable extent in countries and regions in the world, such as canada, singapore, australia, and the like, in addition to europe. Compared with the traditional AM/FM broadcasting system, DAB (digital Audio broadcasting) has the advantages of saving frequency spectrum resources, low transmission power, large information quantity, excellent tone quality and the like, and is the third generation broadcasting following the traditional amplitude modulation and frequency modulation broadcasting. The digital broadcast has the advantages of noise resistance, interference resistance, wave propagation fading resistance, suitability for high-speed mobile reception and the like, provides CD-level stereo sound quality, and has almost zero signal distortion.

T-DMB is a terrestrial digital multimedia broadcasting system introduced in korea, and is still an international standard in europe in a strict sense. The standard is based on the Digital Audio Broadcasting (DAB) system 147 developed by European manufacturers, and some modifications are made to broadcast digital television programs over the air to handheld devices such as mobile phones, PDAs and portable televisions. T-DMB has already come into the commercial stage in korea. Korea has issued a new license to T-DMB broadcasting operators. Meanwhile, the DVB-H mobile digital tv broadcasting system developed in europe has just started to perform experimental work.

The T-DMB fully utilizes the technical advantages of DAB (can reliably receive signals under a high-speed mobile environment), and functionally expands single audio information to various carriers such as data, characters, graphics, videos and the like. The T-DMB performs compression, encoding, modulation, transmission, and other processes on digitized audio and video signals and various data service signals in a digital state, can realize high-quality transmission, has multimedia characteristics, and provides data information transmission with large capacity, high efficiency, and strong reliability. From DAB to T-DMB, which means the transition from digital audio broadcasting to digital multimedia broadcasting, any digital information can be delivered by a digital platform system, which can provide users with comprehensive audiovisual information services including audio and video and entertainment enjoyment.

The DVB-H standard is known as Digital Video Broadcasting handset, and is a transmission standard established by the european DVB organization for providing multimedia services to portable/Handheld terminals through a terrestrial Digital Broadcasting network after a series of standards for Digital television transmission are introduced.

DVB-H is a standard that builds on both DVB (data broadcasting) and DVB-T (transmission), and is considered an extended application of the DVB-T standard, although it is a transmission standard, in fact focuses on protocol implementation. The front end of the system consists of a DVB-H packaging machine and a DVB-H modulator, wherein the DVB-H packaging machine is responsible for packaging IP data into an MPEG-2 system transport stream, and the DVB-H modulator is responsible for channel coding and modulation; the system terminal is composed of a DVB-H demodulator and a DVB-H terminal, wherein the DVB-H demodulator is responsible for channel demodulation and decoding, and the DVB-H terminal is responsible for displaying and processing related services.

The DVB-H keeps part of compatibility with a DVB-T receiving circuit, and meanwhile, in order to meet the receiving characteristics of a handheld device, such as low power consumption, high mobility, uninterrupted service of common platform and network switching and the like, normal watching on indoor, outdoor, walking or running automobiles is ensured, and a plurality of technical improvements are made. In order to prolong the service time of the battery, the terminal periodically turns off a part of receiving circuits so as to save power consumption; in order to meet the requirement of portability, the antenna of the DVB terminal is smaller and more flexible to move; the transmission system can ensure that the DVB-H service can be successfully received under various moving speeds; the system has strong anti-interference capability and can provide enough flexibility to meet different transmission bandwidths and channel bandwidth applications and the like.

MediaFLO technology, proposed by qaulcom, is essentially a new type of air interface. It is designed for mobile multicast reception entirely: the method realizes fast channel switching, and the receiver has low energy consumption and abundant service contents. The modulation mode will support robust data rates up to 11Mbps in one 6MHz channel. Highlighting the fast channel change time as 1.5 seconds on average and as one of the jokers over other competing mobile television standards. And sending different programs by adopting a TDM mode, extracting target service sending time from the transmission frame header information by a receiver, and starting to receive at the moment. In the united states, Qualcomm purchases a 700MHz frequency point (UHF TV Channel 55) capable of transmitting up to 50kW of power.

The three standards of T-DMB, DVB-H and MediaFLO all have different levels of defects: the T-DMB has a low spectrum utilization rate, does not provide sufficient information throughput to satisfy high quality services such as mobile tv, and does not provide sufficient power saving measures for a receiver; because DVB-H inherits DVB-T (fixed receiving system), the space for optimizing the mobile environment is very limited on the basis, the DVB-H cannot provide enough power saving mechanism for a receiver and sacrifices some other performance indexes, such as the switching time is increased to 5 seconds, and in addition, the available working frequency points are less; MediaFLO is an independent system, has no compatibility, is designed mainly for 700MHz frequency points, and has no universality.

Disclosure of Invention

In view of the above, the present invention provides a DAB-compatible terrestrial mobile multimedia broadcasting transmission method, which can effectively transmit multimedia broadcasting service data in a mobile environment.

The invention also provides a ground mobile multimedia broadcasting receiving method compatible with DAB, which can effectively receive multimedia broadcasting service data in a mobile environment.

The invention also provides a DAB compatible ground mobile multimedia broadcasting system, and the system can realize effective transmission and reception of multimedia broadcasting service data in a mobile environment.

In order to achieve the purpose, the technical scheme of the invention is realized as follows:

a terrestrial mobile multimedia broadcasting transmission method compatible with DAB presets the service type of multimedia broadcasting, the service type includes T-MMB service of terrestrial mobile multimedia broadcasting, the method includes:

receiving multimedia broadcasting service data, and sequentially performing source coding and channel coding on the service data according to the service type of the multimedia broadcasting service data;

embedding the coded data into a main service channel MSC of the system in a time division multiplexing mode, correspondingly identifying the service type, occupied sub-channel information, an information source coding mode, a channel coding mode and a channel modulation mode corresponding to the service data in a fast information channel FIC of the system, and carrying out channel coding on the data in the FIC channel;

and carrying out channel modulation on the data of the FIC channel and the MSC channel according to the determined transmission mode and the channel modulation mode, carrying out OFDM modulation and radio frequency modulation on the data of the FIC channel, the MSC channel and the synchronous channel after channel modulation, and then sending out the data.

Preferably, between the source coding and the channel coding of the received service data, the method may further include performing conditional access scrambling and energy spreading on the source coded data in sequence; and further comprises time interleaving the channel-coded data after the channel coding and before the time division multiplexing.

Preferably, when the service type is T-MMB service, the channel coding may be to perform channel coding on the service data by using a concatenated code or a low density parity check LDPC code.

Preferably, the channel modulation on the T-MMB service data in the transmission frame may be performed by using 4-point differential phase shift keying DQPSK, 8-point differential phase shift keying 8DPSK, 16-point differential amplitude and phase joint keying 16DAPSK, or 64-point differential amplitude and phase joint keying 64 DAPSK.

Preferably, when the coded data is embedded into the main service channel MSC of the DAB system in a time division multiplexing manner, the size of the corresponding capacity unit CU in the MSC is determined according to the channel modulation manner of the service data.

Preferably, the determining the size of the corresponding CU in the MSC is: n × 32bits, where n ═ 2 represents a service data DQPSK modulation mode, n ═ 3 represents that the service data adopts an 8DPSK modulation mode, n ═ 4 represents that the service data adopts a 16DAPSK modulation mode, n ═ 5 represents that the service data adopts a 32DAPSK modulation mode, and n ═ 6 represents that the service data adopts a 64DAPSK modulation mode.

Preferably, the correspondingly identifying the service type, the occupied sub-channel information, the source coding mode, the channel coding mode and the channel modulation mode corresponding to the service data in the fast information channel FIC of the system may be:

the method comprises the steps of establishing an FIG of an FIC channel of a T-MMB system based on a quick information group FIG of the FIC channel of the DAB system, and identifying a service type, occupied sub-channel information, an information source coding mode, a channel coding mode and a channel modulation mode corresponding to service data in the FIG of the FIC channel of the T-MMB system.

Preferably, when the service type is T-MMB service, the service type corresponding to the service data identified in FIG of the FIC channel of the T-MMB system may be: adding the service type description of the T-MMB system in the data service component type field in the FIG type 0/the extended mode 2 of the FIC channel of the T-MMB system; and adding the Application description of the T-MMB User in the field of the User Application Type in the FIG Type 0/extended mode 13 of the FIC channel of the T-MMB system.

Preferably, when the service type is T-MMB service, the sub-channel information for identifying service data occupation in FIG of the FIC channel of the T-MMB system may be: adding a sub-channel identification field in the FIG of the FIC channel of the T-MMB system for identifying the sub-channel occupied by the service data; a start address field is added to the FIG of the FIC channel of the DAB system for identifying the address of the first CU of a sub-channel.

Preferably, when the service type is T-MMB service, the channel coding mode and the channel modulation mode for identifying the service data in FIG of the FIC channel of the T-MMB system may be:

adding a coding type field in the FIG of the FIC channel of the T-MMB system for identifying a channel coding mode of the T-MMB service;

adding a Sub-channel data area Sub-channel field in the FIG of the FIC channel of the T-MMB system, wherein the Sub-channel data area Sub-channel field is used for identifying the size of the Sub-channel of the T-MMB service and the protection level of the adopted error correction coding;

and adding a modulation type ModuType field in the FIG of the FIC channel of the T-MMB system for identifying the channel modulation mode of the T-MMB service.

Preferably, the determining the transmission mode may be:

and determining the transmission mode according to the adopted channel modulation mode and the working frequency point appointed by the system by referring to the corresponding relation among the preset channel modulation mode, the transmission mode and the working frequency point.

Preferably, when the channel modulation mode is m-DPSK or m-DAPSK, if the working frequency point of the T-MMB is BandIII, the transmission mode IV is adopted, and if the working frequency point of the T-MMB is L-Band, the transmission mode III is adopted; m is one or any combination of 16, 32 or 64;

and when the channel modulation mode is DQPSK, if the working frequency point of the T-MMB is BandIII, adopting a transmission mode I, and if the working frequency point of the T-MMB is L-Band, adopting a transmission mode II.

A DAB-compatible terrestrial mobile multimedia broadcasting receiving method, comprising:

performing radio frequency demodulation, OFDM demodulation and synchronization on the received signals to obtain data of an FIC channel and an MSC channel, and judging an adopted transmission mode;

sequentially carrying out channel demodulation and channel decoding on the data of the FIC channel, and extracting service data in the sub-channel of the corresponding service type in the MSC channel according to the control information of the FIC channel;

and according to the judged transmission mode and the channel modulation, channel coding and source coding modes of various service data identified in the FIC channel, sequentially carrying out channel demodulation, channel decoding and source decoding on the extracted service data.

Preferably, the determination transmission mode may be:

and judging the transmission mode according to the adopted channel modulation mode and the working frequency point appointed by the system by referring to the corresponding relation between the preset channel modulation mode and the transmission mode and the working frequency point.

A DAB-compliant terrestrial mobile multimedia broadcasting system, the system comprising: a Network Control Center (NCC), a transmitting station, and a receiver, wherein,

the NCC is used for sending the multimedia broadcast service data to the transmitting station;

the transmitting station is used for receiving the multimedia broadcast service data from the NCC, performing source coding and channel coding on the multimedia broadcast service data according to the service type of the multimedia broadcast service data, embedding the coded data into the MSC of the system in a time division multiplexing mode, correspondingly marking the service type corresponding to the service data, the occupied sub-channel information, the source coding mode, the channel coding mode and the channel modulation mode in the fast information channel FIC, and performing channel coding on the data in the FIC channel; the system is also used for carrying out channel modulation on the data of the FIC channel and the MSC channel according to the determined transmission mode and the channel modulation mode, carrying out OFDM modulation and radio frequency modulation on the data of the FIC channel and the MSC channel after the channel modulation and the data of the synchronous channel, and transmitting the data to the receiver in the system;

the receiver is used for performing radio frequency demodulation, OFDM demodulation and synchronization on the received radio frequency signals sent by the transmitting station; and extracting service data in the sub-channels of the corresponding service types according to control information of the FIC channel obtained after channel demodulation and channel decoding, and performing channel demodulation, channel decoding and information source decoding.

Preferably, the transmitting station comprises a receiving module, a source coding module, a channel coding module, a FIC data forming module, a channel multiplexing module and a modulation transmitting module, wherein,

the receiving module is used for receiving the multimedia broadcast service data from the NCC and forwarding the service data to the information source coding module;

the signal source coding module is used for carrying out signal source coding on the signal forwarded by the receiving module according to the service type of the service data and then sending a signal source coding result to the channel coding module;

the channel coding module is used for carrying out channel coding on the received data and sending the result to the channel multiplexing module;

the FIC data forming module is used for correspondingly identifying the service type, the occupied sub-channel information, the information source coding mode, the channel coding mode and the channel modulation mode corresponding to the service data in the FIC, carrying out channel coding on the data in the FIC channel, and sending the coding result to the channel multiplexing module;

the channel multiplexing module is used for inserting the received service data into an MSC channel in a time division multiplexing mode according to the service type, multiplexing the data of the MSC channel and the FIC coding result sent by the FIC data forming module and then sending the result to the modulation sending module;

and the modulation sending module is used for carrying out channel modulation on the data of the received FIC channel and the data of the received MSC channel according to the determined transmission mode and the determined channel modulation mode, carrying out OFDM modulation and radio frequency modulation on the data of the FIC channel and the data of the MSC channel after the channel modulation and the data of the synchronous channel, and sending the data to the receiver.

Preferably, the transmitting station may further include a conditional access scrambler, an energy spreader, and a time interleaver, wherein,

the source coding module is used for sending a source coding result to the conditional access scrambler;

the conditional access scrambler is used for performing conditional access scrambling on the received data and then sending the data to the energy diffuser;

the energy diffuser is used for transmitting the received data to the channel coding module after energy diffusion;

the channel coding module is used for sending the result after channel coding to the time interleaver;

the time interleaver is configured to time interleave the received data and send the interleaved data to the channel multiplexing module.

Preferably, the receiver may be: one or any combination of DAB receiver, DAB-IP receiver, digital multimedia broadcasting T-DMB receiver and T-MMB receiver.

Preferably, the T-MMB receiver may include a reception demodulation module, a service data extraction module, a channel decoding module, and a source decoding module, wherein,

the receiving and demodulating module is configured to receive the radio frequency signal sent by the transmitting station, perform radio frequency demodulation, OFDM demodulation, and synchronization on the received signal, obtain data of an FIC channel and an MSC channel, and send the data to the FIC data extracting module and the service data extracting module, respectively;

the FIC data extraction module is used for performing channel demodulation and channel decoding on the received FIC channel data and sending control information of the FIC to the service data extraction module, the channel demodulation module, the channel decoding module and the information source decoding module;

the service data extraction module is used for extracting various service data in the MSC according to the control information provided by the FIC and sending the various service data to the channel demodulation module;

the channel demodulation module is used for carrying out channel demodulation on the received service data according to the distinguished transmission mode and the channel modulation modes of various service data identified in the FIC channel, and sending the demodulated data to the channel decoding module;

the channel decoding module is used for performing corresponding channel decoding on the received signal according to the channel coding mode of the signal identified in the FIC channel, and sending the result to the information source decoding module;

and the information source decoding module is used for carrying out information source decoding on the received signals according to the service types.

It can be seen from the above technical solution that, the invention is based on the DAB system, the service type of the multimedia broadcast required to be transmitted is preset, and after the transmitting end of the multimedia broadcast service data receives the original service data of the multimedia broadcast, the source and channel coding is performed on the service data according to the service type; then, embedding the coded data into MSC of the system in a time division multiplexing mode, correspondingly marking control information such as sub-channels corresponding to the service data in FIC, and carrying out channel coding on the data in the FIC channel; and then, the data multiplexed by the MSC and the FIC is subjected to channel modulation, OFDM modulation and radio frequency modulation and then is sent out. At a receiving end, the received data is correspondingly subjected to radio frequency demodulation and OFDM demodulation to obtain FIC channel data, the FIC channel data is subjected to channel demodulation and channel decoding, and then the data on each service channel is subjected to channel demodulation, channel and information source decoding according to the extracted FIC channel control information to obtain original service data. Accordingly, the system can support the transmission of a plurality of multimedia broadcasting service data by identifying the sub-channels used for different types of service data and their coded modulation schemes in the FIC.

Furthermore, because a high-efficiency channel coding modulation mode can be adopted, the frequency band utilization rate of the system can be improved, and stronger anti-interference capability can be provided for the transmitted data, so that the method is more suitable for the transmission of video programs.

In a word, the scheme is based on the mature DAB system multimedia service expansion, the DAB system is designed for the handheld mobile terminal, and the DAB system is proved to be reliable; the scheme overcomes the defects of low frequency band efficiency and single service of the existing DAB system, and is more suitable for video program transmission; compared with other systems of mobile multimedia technology, the invention has good frequency point availability; the synchronization is simple and easy to realize; the compatibility is good; the frequency band utilization rate is high, and the portable and mobile receiving is supported; the receiver has the advantages of low complexity, easy realization and the like.

Meanwhile, the invention can be used not only in the ground, satellite and other transmission media, but also in the data broadcast, internet, and other broadband multimedia information transmission and comprehensive data service fields.

Drawings

Fig. 1 is a general flow chart of the DAB compatible T-MMB transmission method of the present invention.

Fig. 2 is a general flow chart of the DAB compatible T-MMB receiving method of the present invention.

Fig. 3 is a general structural diagram of the DAB compatible T-MMB system of the present invention.

Fig. 4 is a functional block diagram of the T-MMB transmission method of the present invention.

Fig. 5 is a specific flowchart of a DAB-compatible T-MMB transmission method in an embodiment of the present invention.

Fig. 6 is a diagram of an RS outer interleaver and a deinterleaver employed in an embodiment of the transmission method of the present invention.

FIG. 7a is a frame structure of a T-MMB system when the modulation mode is 8DPSK channel coding mode is LDPC code.

FIG. 7b is a frame structure of the T-MMB system when the modulation mode is 16DAPSK and the channel coding mode is RS + convolutional concatenated code.

Fig. 8 is a structural diagram of a service organization region of an FIC information channel employed in an embodiment of the transmission method of the present invention.

The meanings of the respective symbols in fig. 10 are as follows:

and SId: a service identifier.

Service Identifier description:

-Country Id: a country identifier.

-Service reference: and (4) service reference.

-ECC: an extended country code.

Local flag: and (4) local marking.

CAId: a conditional access identifier.

Number of service components: number of service components

Service component description (Service component description):

-TMId: transport mechanism identifier

-ASCTy: audio service component type

-subchidd: sub-channel identifier

-P/S: primary/secondary identification

-CAflag: CA marking

-DSCTy: data service component type

-FIDCId: fast information data channel identifier

The above identified details can be seen in the DAB standard (ETSI EN 300401).

Fig. 9 is a structural diagram of a new traffic subchannel of an FIC information channel employed in an embodiment of the transmission method of the present invention.

Fig. 10 is a structural diagram of user application information of an FIC information channel employed in an embodiment of a transmission method of the present invention.

Fig. 11 is a 8PSK symbol constellation diagram used in the embodiment of the transmission method of the present invention.

Fig. 12 is a 16APSK symbol constellation diagram adopted in the embodiment of the transmission method of the present invention.

Fig. 13 is a specific flowchart of a method for receiving a DAB-compliant T-MMB according to an embodiment of the present invention.

Fig. 14 is a specific structural diagram of a DAB-compatible T-MMB system in an embodiment of the present invention.

Fig. 15 is a specific structural diagram of a transmitting station of a T-MMB transmission system compatible with DAB in an embodiment of the present invention.

Fig. 16 is a specific structural diagram of a T-MMB receiver in the embodiment of the present invention.

Detailed Description

The core idea of the invention is as follows: presetting the service type of multimedia broadcasting required to be transmitted, receiving original service data of the multimedia broadcasting at a transmitting terminal of the multimedia broadcasting service data, and then carrying out information source and channel coding on the service data according to the service type; then, embedding the coded data into MSC of the system in a time division multiplexing mode, correspondingly marking control information such as sub-channels corresponding to the service data in FIC, and carrying out channel coding on the data in the FIC channel; and then, the data multiplexed by the MSC and the FIC is subjected to channel modulation, OFDM modulation and radio frequency modulation and then is sent out. At a receiving end, the received data is correspondingly subjected to radio frequency demodulation and OFDM demodulation to obtain FIC channel data, the FIC channel data is subjected to channel demodulation and channel decoding, and then the data on each service channel is subjected to channel demodulation, channel and information source decoding according to the extracted FIC channel control information to obtain original service data.

The present invention is a new multimedia transmission system and method based on the original DAB system, in the present invention, the channel constitution is the same as the DAB system, including FIC channel, MSC channel and synchronous channel. The MSC channel carries service data, the FIC channel carries control data, and the synchronization channel is used for realizing signal synchronization.

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and preferred embodiments.

Fig. 1 is a general flow chart of the DAB compatible T-MMB transmission method of the present invention. As shown in fig. 1, the method includes:

step 101, presetting a service type of multimedia broadcasting, wherein the service type comprises a T-MMB service of ground mobile multimedia broadcasting.

Step 102, receiving multimedia broadcast service data, and sequentially performing source and channel coding on the received service data according to the service type of the multimedia broadcast service data.

Step 103, embedding the coded data into the main service channel MSC of the system in a time division multiplexing manner, correspondingly identifying the service type, occupied sub-channel information and coding modulation manner corresponding to the service data in the fast information channel FIC, and performing channel coding on the data in the FIC channel.

And 104, performing channel modulation on the data of the FIC channel and the MSC channel according to the determined transmission mode and the channel modulation mode, performing OFDM modulation and radio frequency modulation on the data of the FIC channel and the MSC channel after the channel modulation and the data of the synchronous channel, and then sending out the data.

Accordingly, fig. 2 is a general flowchart of the DAB-compliant T-MMB receiving method according to the present invention. As shown in fig. 2, the method includes:

step 201, receiving the sending data of the sending end, performing radio frequency demodulation, OFDM demodulation and synchronization on the sending data to obtain data of the FIC channel and the MSC channel, and determining the adopted transmission mode.

Step 202, sequentially performing channel demodulation and channel decoding on the data of the FIC channel, and extracting the service data in the sub-channel of the corresponding service type in the MSC channel according to the control information of the FIC channel.

And step 203, sequentially performing channel demodulation, channel decoding and source decoding on the extracted service data according to the judged transmission mode and the channel modulation, channel coding and source coding modes of various service data identified in the FIC channel.

Fig. 3 is a general structural diagram of the DAB compatible T-MMB system of the present invention. As shown in fig. 3, the system includes: a Network Control Center (NCC)310, a transmitting station 320, and a receiver 330.

In the system, the NCC 310 is configured to transmit multimedia broadcast service data to the transmitting station 320. The transmitting station 320 receives the multi-channel digital multimedia broadcasting (program) signal from the NCC 320, performs source coding and channel coding on the signal according to the service type of the signal, embeds the coded data into the MSC of the system in a time division multiplexing manner, correspondingly identifies the service type, occupied sub-channel information, the source coding manner, the channel coding manner and the channel modulation manner corresponding to the service data in the fast information channel FIC, and performs channel coding on the data in the FIC channel; and is further configured to perform channel modulation on the data of the FIC channel and the MSC channel according to the determined transmission mode and the channel modulation manner, perform OFDM modulation and radio frequency modulation on the data of the FIC channel and the MSC channel after the channel modulation and the data of the synchronization channel, and transmit the data to the receiver 330.

A receiver 330 for performing radio frequency demodulation, OFDM demodulation, and synchronization on the received radio frequency signal; and extracting service data in the sub-channels of the corresponding service types according to control information of the FIC channel obtained after channel demodulation and channel decoding, and performing channel demodulation, channel decoding and information source decoding.

The foregoing is a general overview of the DAB compatible T-MMB transmission and reception method and system of the present invention. The processing of the service data before multiplexing to the MSC channel is source coding and channel coding. In fact, in practical application, as in the DAB system, it is also possible to add optional processes of conditional access scrambling and energy spreading between the source coding and the channel coding, and add a process of time interleaving after the channel coding, so as to better adapt to the channel environment with stronger time variability.

T-MMB is a digital multimedia broadcasting mode based on the multimedia service expansion of a digital audio broadcasting DAB system, integrates the latest technology, comprehensively considers the factors such as frequency point resources, receiver complexity, frequency spectrum utilization rate and system performance, and overcomes the problems of the technology to realize: the method is completely compatible with DAB, low in cost design, low in power consumption design, good in frequency point availability, capable of supporting mobile reception, single frequency network implementation, high spectrum efficiency, multi-service, high-quality service and the like. It has the following characteristics:

(1) it is fully compatible with Eureka-147(DAB), DAB-IP in UK and T-DMB in Korea. The T-MMB fully utilizes the technical advantages of DAB (can reliably receive signals in a high-speed mobile environment), and functionally expands single audio information to various carriers such as data, characters, graphics, videos and the like.

(2) The defect of low frequency band efficiency of the DAB system is overcome.

(3) An LDPC code and a DAPSK modulation scheme with high efficiency and low complexity are adopted.

(4) Compared with other standards such as DVB-H and MediaFLO, the method has the advantages of low complexity, low power consumption, good frequency point availability, good compatibility and the like.

The invention utilizes the transmitter of the existing DAB system to embed new multimedia services into the old DAB system in a sub-channel to form a new T-MMB system. Multimedia information such as audio and video programs or data, texts, pictures and the like is subjected to source coding, transmission coding and channel coding (an old service DAB signal is in a traditional coding mode, and a new service T-MMB signal is in a new coding mode) and then is transmitted out through one or more transmitters to cover a certain area. These transmitters can be flexibly networked, and can form a Multi-Frequency Network (MFN) or a single-Frequency Network (sfn).

Fig. 4 is a functional block diagram of the T-MMB transmission method of the present invention. As shown in fig. 4, the T-MMB system signal structure is composed of three major parts, a compression layer, a transport layer and a physical layer. The transmitting signal of the T-MMB system can be synthesized by four paths of signals: DAB signals, DAB-IP signals, T-DMB signals and T-MMB signals, wherein the T-MMB, T-DMB and DAB-IP signals are embedded in the DAB system in independent services. The main difference between the four signals is in the physical layer.

From another aspect, the transmission end baseband signal of the T-MMB system can be divided into parts such as source compression coding, code stream multiplexing, channel error correction coding, channel modulation and the like. The code stream multiplexing belongs to the transmission layer, and is mainly characterized by that according to MPEG-2 system layer specification, the multiplexing of several basic code streams is implemented, and several code streams of audio code stream, video code stream and data code stream are combined into one transmission code stream, and its transmission packet length is fixed so as to facilitate transmission of channel. The structure of DAB and T-DMB signal transmission layers is kept unchanged, the structure of the T-MMB signal transmission layer is different from that of the traditional DAB system, and different error correction coding and modulation technical schemes are adopted, so that the frequency spectrum efficiency and the error correction performance are improved, and the T-MMB system is suitable for transmitting video programs. In addition, the FIC information channel transport layer structure remains unchanged as well. According to the transmission layer structure, the digital code stream is changed into data symbols and inserted into the synchronous channel, a baseband signal is formed by the OFDM signal generator and sent to the radio frequency modulator of the DAB transmitter, and the radio frequency bandwidth of the baseband signal is the same as that of the DAB.

The focus of the present invention is on the transport layer. In order to be compatible with the existing DAB system, the invention reserves the transmission structure of the DAB system, and the T-MMB system only modifies the transmission layer structure of the newly added sub-service channel of the DAB system and keeps the aspects of the frame structure, the multiplexing mode, the interleaving mode, the FIC structure, the synchronous channel, the OFDM signal generator structure, the transmitter and the like of the system transmission unchanged. More specifically, the T-MMB system extends the support of the DAB system for new channel coding and modulation techniques so that the T-MMB system can transmit video programs. The technical details involved in the present invention will be described below with respect to the newly added part of the present invention based on the DAB system, and the same part of the T-MMB system as DAB will not be described.

The embodiment of the invention takes four types of service data transmission of DAB, DAB-IP, T-DMB and T-MMB as an example, and illustrates the specific implementation mode of the method and the system for receiving and transmitting the multimedia broadcasting service data.

Example (b):

fig. 5 is a specific flowchart of a DAB-compatible T-MMB transmission method in an embodiment of the present invention. In this embodiment, before service data is multiplexed to the MSC main channel, source coding, conditional access scrambling, energy spreading, channel coding, and time interleaving are sequentially performed, which is consistent with the processing procedure of the DAB system. As shown in fig. 5, the method specifically includes:

step 501, presetting a service type of multimedia broadcasting, wherein the service type comprises a T-MMB service of terrestrial mobile multimedia broadcasting.

In this step, the service types to be transmitted are set to include four types of service data, namely, DAB-IP, T-DMB and T-MMB.

Step 502, receiving multimedia broadcast service data, and according to the service type, performing source coding, conditional access scrambling and energy diffusion on the received service data.

Source coding is the aforementioned compression layer, and includes compression coding of sound and images. In this step, the source compression can be performed on the data of four service types mainly according to series standards such as MPEG1, MPEG2, MPEG4, AVS and the like of ISO/IEC, and with the development of technology, other new compression algorithms such as wavelet coding, fractal coding and the like can be adopted. And after the information source compression is completed, forming a corresponding data stream or data packet. Then, conditional access scrambling and energy spreading are carried out, and the process is carried out in a DAB system. Of course, since the conditional access scrambling is an optional operation in the DAB system, the conditional access scrambling may not be processed here.

Step 503, according to the service type, performing channel coding and time interleaving on the service data after energy spreading.

In this step, for the DAB service data and DAB-IP service data, the channel coding mode of audio (program) and data service defined by the DAB system EN300401 [1] can be adopted. However, although the error protection method in the MSC streaming mode can guarantee the performance of the audio service, the performance of the data service, such as the video service, transmitted in the streaming mode cannot be guaranteed. Therefore, in the present embodiment, a stronger error correction coding scheme is specified for the T-MMB signal, and the specific channel coding may be an RS + convolutional concatenated code or an LDPC code.

Rs + convolutional concatenated code

In order to make the transmitting and receiving devices as common as possible, the outer coding directly uses the standard of DVB-T EN 300744, providing suitable error protection.

In the present embodiment, an additional outer coding (RS coding) and outer interleaving (convolutional interleaving) process is provided. The process is located between MPEG-2 transport multiplexing and DAB sub-channel stream multiplexing.

The process is in accordance with the definition in EN 300744.

Error protection of DAB subchannel data stream and 188 byte transport packets:

1) general principles

Each input transport packet is 188 bytes long and the start byte is a sync byte and has a value of 0 x 47. The transport packet may contain arbitrary data. For more details of the transport packet format, reference may be made to ISO/IEC 13818.

2) Outer coding

Outer code and outer interleaving transport packets for input are shown in table 1.

Synchronous byte 0 x 47

MPEG-2 transport stream data (187 bytes)

TABLE 1

The RS (204, 188, t 8) puncturing code is derived from the systematic RS (255, 239, t 8) encoding for each transmitted packet (188 bytes), resulting in one error protected packet. The protection range of RS encoding contains sync bytes (0 × 47). In this embodiment, the RS encoding length is set to 204 bytes, and the information segment is set to 188 bytes, so that errors within any 8 bytes of the received 204 bytes can be corrected.

The code generator polynomial is: g (x) ═ x + λ⁰)(x+λ¹)(x+λ²)…(x+λ¹⁵) Where λ is 2.

The domain generator polynomial is: p (x) x⁸+x⁴+x³+x²+1。

The truncated RS code may add 51 bytes of 0 at the front of 188 information bytes and then input to the RS (255, 239, t-8) encoder. After RS encoding, the added 51 bytes 0 are discarded, resulting in an RS code of N204, as shown in table 2.

Synchronous byte 0 x 47

MPEG-2 transport stream data (187 bytes)

Check word (16 bytes)

TABLE2

3) Outer interweaving

The outer interleaving of bytes is based on the method of Forney, and the interleaving depth I is 12, as shown in fig. 6. According to the method shown in fig. 6, a convolutional interleaver with an interleaving depth I of 12 is used for error-protected packets.

The convolutional interleaving process is based on the method of Forney, and is compatible with the method of Ramsey type III, and I is 12. The interleaver has branches with I-12, which are connected by an input switch with a period equal to the input stream. Each branch j is a first-in-first-out (FIFO) shift register with a width of j.m units, where M is 17N/I and N is 204. Each FIFO cell contains one byte and the input and output switches need to be synchronized. For synchronization, the sync byte (0 × 47) must always go through branch "0" of the interleaver (corresponding to no delay).

The deinterleaver follows a similar principle to the interleaver, but with the branch pointers reversed (i.e., j equals 0 for maximum delay). The synchronization of the deinterleaving may be achieved by passing the first identified sync byte through branch "0".

LDPC coding

The LDPC code is similar to the convolutional code and can provide a forward error correction function, but the LDPC code has stronger error correction performance and is more suitable for information propagation of a bad channel, and the LDPC code converges after several iterative decoding under high signal-to-noise ratio. The receiver is more power efficient under the same conditions. Properly designed LDPC codes have a very low error floor, in which case no concatenated outer codes are needed.

The LDPC code in the embodiment of the invention provides equal error protection for the same service, and different services are independently coded. The forward error correction coding adopts LDPC codes with a quasi-cyclic structure, and the quasi-cyclic LDPC codes can be coded by using a shift register and are convenient to store.

The check matrix H of a quasi-cyclic LDPC code can be represented as follows:

wherein A is_i，jIs a row (column) weight of omega_i，jT x t dimensional cyclic matrix, and ω_i，jAnd < t. The codeword characterized by the matrix H is called an (N, K) LDPC code, where N ═ c × t is the code length, and K ═ c- ρ × t denotes the length of the encoded information bits. A. the_i＝[A_i，1，A_i，2，…，A_i，c]When i is 1, 2, …, the first line of ρ is called the i-th line generator of H, and H has ρ line generators in total.

The generator matrix G corresponding to the check matrix H can be represented as: g ═ I | P ], where I is a unitary matrix, the quasi-cyclic matrix P can be represented as follows:

P_j＝[P_1，j，P_2，j，…P_c-ρ，j]^Twhere j is 1, 2, …, the first column of ρ is called the jth column generator that generates matrix G, and G has ρ row generators.

The encoding process is as follows: firstly, filling b 0 bits after the source bit to obtain the coding information bit with the length of K, and then carrying out LDPC coding. The number of 0 s filled in the LDPC code with different code rates is different. Table 3 shows the encoding parameters of the LDPC code with two code rates.

N	K	b	t	ωi，j
					4608	2304	0	72	0 or 1
4608	3096	24	72	0 or 1

TABLE 3

And performing channel coding on the T-MMB service data by adopting the proper channel coding scheme according to the requirement, thereby obtaining better anti-interference performance.

In order to better adapt to the channel environment with strong time variability, the service data after channel coding can be time interleaved, which is also a big guarantee that the DAB system is suitable for mobile reception. In this embodiment, the channel-coded data is also time-interleaved in the same time-interleaving manner as in the DAB system.

Step 504, the service data after time interleaving is embedded into the main service channel MSC of the DAB system in a time division multiplexing manner.

In this embodiment, the system transmission frame adopts the same format as the DAB transmission frame. Its main traffic channel consists of Common Interleaved Frames (CIFs). The minimum address unit of one CIF is a Capacity Unit (CU). Each CIF consists of 864 CUs. The size of a CU is 32 × n bits. The value of n is three, which respectively corresponds to three different differential modulation modes: n-2 (DQPSK), n-3 (8DPSK) and n-4 (16 DAPSK). Taking the transmission mode I, T-MMB service as an example when transmitted in streaming mode: when the modulation mode is 8DPSK and the channel coding mode is LDPC code, the frame structure of the T-MMB system is as shown in fig. 7 a; when the modulation scheme is 16DAPSK and the channel coding scheme is RS + convolutional concatenated code, the frame structure of the T-MMB system is shown in FIG. 7 b.

Of course, in practical applications, higher-order channel modulation schemes such as 32DAPSK (n is 5), 64DAPSK (n is 6), and the like may also be used.

As can be seen from fig. 7, the transmission method in this embodiment reserves the frame structure of the DAB system, the sizes of CUs corresponding to DAB, DAB-IP, and T-DMB signals are unchanged, the size of CU corresponding to T-MMB signals is changed according to the modulation method, but the number of CUs included in the CIF is unchanged. The system frame structure in this embodiment may enable the newly added service to support multiple modulation modes.

Fig. 7 above is a frame structure illustrated when T-MMB traffic is transmitted in a streaming mode. In fact, the method of the invention can also support the transmission of the T-MMB service in a packet mode. When the T-MMB service is transmitted in the packet mode, the frame structure is formed similarly to fig. 7, except that the packet mode of DAB is firstly packed into a data packet of a specific length and then subsequent processing such as channel coding is performed, and if LDPC coding is used, the data packet of the specific length needs to be buffered into an LDPC code length and then coded.

And 505, correspondingly identifying the service types, occupied sub-channel information and the coding modulation modes corresponding to the four service data in the fast information channel FIC, and carrying out channel coding on the data of the FIC channel.

In this embodiment, in order to achieve the purpose of multiplexing and transmitting multiple service data, the service types of various service data, the sub-channel information occupied when the service data is embedded in the MSC, and the coding modulation mode of the service data are correspondingly identified in the FIC. The method specifically comprises the following steps: the method comprises the steps of establishing a Fast Information Group (FIG) of a FIC channel of a T-MMB system based on FIC channel transmission of a DAB system, and identifying a service type, occupied sub-channel information, a source coding mode, a channel coding mode and a channel modulation mode corresponding to service data in the FIG of the FIC channel of the T-MMB system.

a. Service type description

Fig. 8 illustrates service information in DAB defined by fig. 0/extension mode 2(0/2) of fig. 0 transmitted in FIC channel. This definition may refer specifically to ETSI EN 300401. In this embodiment, part of the content of FIG0/2 is expanded as follows:

ASCTy (audio service component type): the 6-bit area indicates the type of audio service component. The embodiment adds the identification of two audio coding modes,

000011：MPEG-4 HE AAC V2

000100：MPEG-4 ER-BSAC

DSCTy (data traffic component type): these 6 bits indicate the type of data service component. This section is explained in detail in TS 101756 [2], definition of table 2. In this embodiment, a new service type identifier is added,

011101：T-MMB Service。

the subchannel information and the coded modulation scheme of each type of traffic are indicated by FIG 0/15(ETSI EN300401 [1]) in the reservation. As shown in particular in fig. 9.

Subchaid (subchannel identifier): this 6-bit region is encoded as an unsigned binary number to indicate a certain subchannel.

Start Address (Start Address): this 10-bit region is encoded as an unsigned binary number (range 0 to 863) indicating the address of the first Capacity Unit (CU) in the subchannel.

ModuType (modulation type): this 2-bit flag is used to indicate that it is a DQPSK/8DPSK/16DAPSK modulation, as follows:

00：DQPSK；

01：8DPSK；

10：16DAPSK；

11: and (5) reserving.

CodingType (coding type): these 1 bit are used to indicate the channel coding mode as follows:

0: RS cascade convolution coding;

1: and (4) LDPC coding.

Rfu: these 1 bit is reserved for future additions. Set to 0 before definition.

Sub-channel field (Sub-channel data area): these 12 bits indicate the size of the subchannel and the channel coding rate.

PL (protection level): these 2bits indicate the channel coding rate as follows:

00: protection level 1-C, indicating that the channel coding code rate is 1/2;

01: protection level 2-C, indicating that the channel coding code rate is 2/3;

others are reserved for future use.

Sub-channel Size (subchannel Size): this 10-bit region is encoded as an unsigned binary number (range 1 to 864) giving the number of capacity units occupied by the subchannel derived from the modulation scheme and the level of protection, see tables 4 and 5. Wherein, table 4 is the data subchannel sizes of different modulation modes when the protection level is 1-C and the data rate is 24n Kbit/s (n is an integer greater than or equal to 1); table 7 shows the data subchannel sizes for different modulation schemes with a guard level of 2-C and a data rate of 32 n Kbit/s (n is an integer greater than or equal to 1).

Modulation system	DQPSK	8DPSK	16DAPSK
				Subchannel Size (CUs)	18n	12n	9n

TABLE 4

Modulation system	DQPSK	8DPSK	16DAPSK
				Subchannel Size (CUs)	18n	12n	9n

TABLE 5

b. Description of user information

The user application information is defined in FIG0/13(ETSI EN300401 [1 ]). In the embodiment, part of the content is expanded on the mode, as shown in fig. 10.

User Application Type (User Application Type): this 11 bits gives the user applications that need to be decoded, identified by the service label (SId) and the service component label (SCId), which are defined with reference to the TS 101756 [2] table 16. This option is expanded in this embodiment, specifically as follows:

0×00b：T-MMB service

user Application data (User Application data): the mx 8 bit data is used to transmit user application information data, and is decoded according to the user application type. For a new service of the T-MMB system, one byte is required to express a service attribute, videoserviceobjectprofile, of the T-MMB system.

The T-MMB video service frames 1, 2 may be identified by VideoServiceObjectProfileId ═ 0 × 01, and VideoServiceObjectProfileId ═ 0 × 02, respectively.

The channel coding process for the FIC channel data is the same as that in the DAB system, and thus will not be described herein.

And step 506, performing channel modulation on the data of the FIC channel and the MSC channel according to the determined transmission mode and the channel modulation mode, performing OFDM modulation and radio frequency modulation on the data of the FIC channel and the MSC channel after the channel modulation and the data of the synchronous channel, and then sending out the data.

In this embodiment, it is specified that one transmission frame is composed of a synchronization channel (Sync), a Fast Information Channel (FIC), and a Main Service Channel (MSC). The basic construction is the same as that of the DAB system and will not be described here.

In this embodiment, for clarity of the technical description of each part, the modulation of OFDM subcarriers is specifically referred to as channel modulation, and the process of OFDM multiplexing and symbol formation is referred to as OFDM modulation. And the radio frequency modulation after the OFDM modulation modulates the OFDM symbols to the appointed working frequency points. In fact, since the channel modulation performed on each channel data is actually modulation performed on OFDM subcarriers, the above two channel modulation and OFDM modulation schemes can be collectively referred to as OFDM modulation.

The channel modulation mode in the original DAB system is 4-point differential phase shift keying (DQPSK). Because the digital video data has a higher code rate, if the channel modulation scheme of the original DAB system is adopted, the defect of low frequency band utilization rate is brought. In order to overcome this drawback, in this embodiment, two new modulation schemes are added to support the DAB system: 8-point differential phase shift keying (8DPSK) and 16-point differential amplitude and phase joint keying (16 DAPSK). The channel modulation methods are all symbol mapping and then differential modulation.

Two additional modulation schemes are specifically described below. First, symbol mapping is introduced:

1) 8-point phase shift keying (8PSK)

The 8PSK constellation is shown in fig. 11. For each OFDM symbol, a vector of 3K-bits (p)_l，n)_n＝0 ^3K-1(wherein p is_l，nSee ETSI EN300401 [1]]Section 14.4.2) needs to be mapped into K8 PSK symbols by:

img id="idf0003" file="A20061016092900301.GIF" wi="87" he="24" img-content="drawing" img-format="GIF"/m＝0，1，2，...，K-1

where K is the number of subcarriers,. phi_l，mAs shown in table 6.

Φl，m	pl，3m pl，3m+1 pl，3m+2
		0	0 0 1
π/4	0 0 0
		π/2	1 0 0
3π/4	1 1 0
		π	0 1 0
5π/4	0 1 1
		3π/2	1 1 1
7π/ 4	1 0 1

TABLE 6

2) 16-point amplitude and phase joint keying (16APSK)

The 16APSK constellation is shown in fig. 12. For each OFDM symbol, a vector of 4K-bits (p)_l，n)_n＝0 ^4K-1Mapping into K16 APSK symbols by:

img id="idf0004" file="A20061016092900302.GIF" wi="110" he="24" img-content="drawing" img-format="GIF"/m＝0，1，2，...，K-1

wherein phi_l，mAs shown in the table 3 below, the following examples,img id="idf0005" file="A20061016092900311.GIF" wi="115" he="23" img-content="drawing" img-format="GIF"/

Φl，m	pl，4m+1 pl，4m+2 pl，4m+3
		0	0 0 1
π/4	0 0 0
		π/2	1 0 0
3π/4	1 1 0
		π	0 1 0
5π/4	0 1 1
		3π/2	1 1 1
7π/4	1 0 1

TABLE 7

Next, differential modulation is introduced:

1)8DPSK

differential modulation is performed on the same subcarrier of two adjacent OFDM symbols (i.e., time domain differential), as follows:

z_l，k＝z_l-1，k·y_l，k，l＝2，3，4，...，L，

-K/2≤k≤K/2

wherein z is_l-1，kDifferential modulation signal, y, representing the k-th subcarrier of the l-1 th OFDM symbol_l，kAnd a mapping signal of a k sub-carrier of the I OFDM symbol after frequency domain interleaving is shown.

2)16DAPSK

DAPSK is a differential amplitude and phase combined modulation scheme. The amplitude and the phase of the differential modulation are respectively and independently carried out differential modulation. The amplitude of 16DAPSK is modulated with 2DASK and the phase is modulated with 8 DPSK.

Differential modulation is performed on the same subcarriers of two adjacent OFDM symbols, and the formula is as follows:

img id="idf0006" file="A20061016092900312.GIF" wi="165" he="23" img-content="drawing" img-format="GIF"/

img id="idf0007" file="A20061016092900313.GIF" wi="116" he="21" img-content="drawing" img-format="GIF"/

img id="idf0008" file="A20061016092900321.GIF" wi="260" he="22" img-content="drawing" img-format="GIF"/l＝2，3，4，...，L，

-K/2≤k≤K/2

wherein R is_LRepresents the inner loop amplitude of 16 DAPSK; p is a radical of_l-1，4k′，p_l.4k' represents the amplitude mapping bits in the corresponding symbols after frequency domain interleaving; phi_l-1，k′，Φ_l，k' indicates phase information after frequency domain interleaving.

The two new channel modulation modes are obtained. Different channel modulation modes can be adopted according to different channels where various data are located. In this embodiment, the data of the FIC channel is still subjected to channel modulation in the DQPSK mode in the DAB system, and the data of the synchronization channel is also used for differential modulation with the data of the FIC channel and the MSC channel, as in the DAB system. DAB, DAB-IP and T-MMB data in the MSC service channel are also subjected to channel modulation by adopting the original DQPSK mode in the DAB system. And the T-MMB signal in the MSC service channel can adopt a proper original or newly added channel modulation scheme according to the requirement.

Since channel modulation is essentially modulation of OFDM subcarriers, before channel modulation, data partitioning is performed, then symbol mapping is performed on data of different channels according to different channel modulation modes, after frequency interleaving is performed on the result of symbol mapping, a phase reference symbol of a synchronization channel is inserted, and differential modulation is performed together with the result of frequency interleaving, so that the whole channel modulation process is completed.

The data on the subcarriers are blocked according to different transmission modes. The transmission mode is that when OFDM modulation is performed in the original DAB system, parameters such as the number of subcarriers, the guard interval length, and the band are combined to form four modes for a user to select. Table 8 gives the parameters for the four modes.

TABLE 8DAB mode parameters

Parameter(s)	Transmission mode I	Transmission mode II	Transmission mode III	Transmission mode IV
					S	76	76	153	76
K	1536	384	192	768
					N	2048	512	256	1024
Ts	～1246	～312	～156	～623
					Tu	1000	250	125	500
TG	～246	～62	～31	～123
					TF	96	24	24	48

Note: notation in Table 8

S: number of OFDM symbols per transmission frame (not including null symbols)

K: number of subcarriers in one OFDM symbol

N: FFT size (dot)

T_s: total duration of one OFDM symbol (mus)

T_u: duration of useful signal (mus) in one OFDM symbol

T_G: guard interval (mus)

T_F: each transmission frame duration (ms)

Theoretically DAB supports various bands, table 9 shows the bands that various modes of DAB allow for use, and table 10 shows the frequency ranges of the various bands.

TABLE 9DAB mode allowed band

Transmission mode	Allowed use of bands in the DAB standard
		Transmission mode I	Band I、Band II、Band III
Transmission mode II	Band I、Band II、Band III、Band IV、Band V、L-Band
		Transmission mode III	＜3GHz
Transmission mode IV	Band I、Band II、Band III、Band IV、Band V、L-Band

TABLE 10 band Range

Wave band	Frequency range (MHz)
		Band I	47-86
Band II	87.5-108
		Band III	174-230
BandIV/V	470-790
		L-Band	1452-1492

At present, the DAB working frequency points Band III and L-Band are distributed in most regions of the world, particularly in Europe, DAB infrastructure accounts for 80%, and practical use conditions of various modes and bands of the DAB are shown in Table 11. There are actually two common modes, Band-III and L-Band. It is worth emphasizing that the correspondence is optimal under the condition that the modulation mode is DQPSK, and when the T-MMB system adopts a high-order modulation scheme, such as 16DAPSK, the correspondence between the current mode and the working frequency point is not optimal. Therefore, a mode needs to be reselected.

TABLE 11 practical use cases

Wave band	Practical used wave band in DAB system	Corresponding transmission mode in DAB system	Recommended transmission mode in T-MMB system
				Band I	Whether or not	Whether or not	Whether or not
Band II	Whether or not	Whether or not	Whether or not
				Band III	Is that	Transmission mode I	Transmission mode IV
Band IV	Whether or not	Whether or not	Whether or not
				L-Band	Is that	Transmission mode II	Transmission mode III

Since the T-MMB system employs a higher order modulation scheme, the influence of the time-varying interference is not negligible. The influencing time-varying interference factors are: moving speed, carrier frequency point, block length of OFDM symbol. In order to resist time-varying interference, the T-MMB system recombines parameters such as the number of carriers, the length of a guard interval, the number of working bands and modulation constellations, and the like. Time-varying interference is resisted by reducing the block length of the OFDM symbol. In order to be compatible with the DAB system, the T-MMB reduces the block length of the OFDM symbols by adjusting the mode corresponding to the actually used waveband of the DAB. Through modification, the T-MMB system supports an efficient and low-complexity 16DAPSK modulation mode and simultaneously supports high-speed mobile reception. Table 11 shows the proposed modes and corresponding bands for the T-MMB system, and the number of carriers of the OFDM symbol is reduced by half compared to DAB, DAB-IP and T-DMB systems.

In this embodiment, the corresponding relationship between the channel modulation mode, the adopted transmission mode, and the working frequency point may be set in advance, for example, when the channel modulation mode adopts DQPSK, the corresponding relationship between the original transmission mode and the working frequency point may be adopted; when the channel modulation mode adopts a more efficient channel coding mode, such as 16QAPSK, the corresponding relationship between the transmission mode and the working frequency point shown in table 11 may be adopted.

Before channel modulation, according to the channel modulation mode to be adopted by each channel data and the working frequency point of the system, determining a transmission mode according to a preset corresponding relation, further determining the size of a data block, and partitioning data of different channels according to the size. Then, according to the setting of each parameter in the transmission mode and the channel modulation mode required by each channel, channel modulation and OFDM modulation are carried out on each channel data, and finally, OFDM symbols are modulated to the appointed working frequency points to be transmitted.

So far, the procedure of the T-MMB transmission method compatible with DAB in this embodiment is ended. It can be seen from the above flow that the transmission method of the present invention can simultaneously transmit multiple service data including DAB, DAB-IP, T-DMB, and T-MMB, and on the basis of the original DAB system, the channel coding and modulation schemes are extended, so that it can support a more efficient coding modulation scheme, in this embodiment, channel modulation modes of 8DPSK and 16DAPSK are added, and certainly, modulation modes such as 64DAPSK and the like can also be adopted. The application of multiple efficient coded modulation schemes makes the system of the present embodiment more suitable for transmitting video data. Further, when the efficient channel modulation mode is adopted, the embodiment modifies the frequency point and the transmission mode applied in practice correspondingly, so as to better adapt to the efficient low-complexity modulation mode.

In the above transmission method, the process of performing source coding and channel coding on the service data and embedding the service data into the MSC channel is performed before the FIC channel id code modulation scheme and the sub-channel information, that is, steps 502 to 504 are performed before step 505. In fact, after determining the coded modulation scheme, the processes of source coding and channel coding and embedding the MSC channel are performed, and the operations of identifying the coded modulation scheme and the sub-channel information with the FIC channel may be performed simultaneously or in reverse order.

Corresponding to the transmission method, the embodiment also provides a receiving method of the T-MMB compatible with DAB. The data processing device is used for receiving the data sent and processed by the transmission method and carrying out corresponding processing to restore the data into original multimedia service data.

Fig. 13 is a specific flowchart of a method for receiving a DAB-compliant T-MMB according to an embodiment of the present invention. As shown in fig. 15, the method includes:

step 1301, performing radio frequency demodulation synchronization and OFDM demodulation on the received signal to obtain data of the FIC channel and the MSC channel.

In this step, the radio frequency demodulation synchronization and OFDM demodulation of the corresponding received data are performed according to the method of the DAB system, which is not described herein again.

Step 1302, performing channel demodulation and channel decoding on the data in the FIC channel, and extracting the service data in the sub-channel of the corresponding service type in the MSC channel according to the control information in the FIC channel.

In this step, channel demodulation and channel decoding are performed on the data of the FIC channel according to the mode in the DAB system, so as to acquire the coding modulation modes of various types of control information and various types of service data in the FIC channel.

Corresponding to the way that the sending end identifies the sub-channel information in the FIC channel, the position of each service type data in the MSC channel is read according to the position of the sub-channel information in the FIC channel in fig. 8, and the four types of service data are extracted according to the position.

And step 1303, performing channel demodulation on the data in the extracted service data MSC channel according to the determined transmission mode and the channel modulation mode of each type of service data identified in the FIC channel.

In this step, the transmission mode is determined by referring to the preset channel modulation mode and the corresponding relationship between the transmission mode and the working frequency point, and according to the adopted channel modulation mode and the working frequency point specified by the system.

When the channel demodulation is carried out on the service data, the channel demodulation is carried out on DAB, DAB-IP and T-DMB signals according to the original DAB standard. For the T-MMB signal, since the channel modulation mode added in this embodiment may be adopted at the transmitting end, it is necessary to extract the control information of the corresponding channel modulation scheme in the FIC channel according to the control information setting of the channel modulation scheme in advance, and perform corresponding channel demodulation according to the identifier therein. Specifically, in this embodiment, since the sending end is based on the channel modulation scheme identified in fig. 8, in this step, the content of the corresponding field is also taken out according to fig. 8, and the channel modulation scheme is analyzed to perform channel demodulation.

And step 1304, performing channel decoding and source decoding on various service data according to the control information in the FIC channel.

In the step, DAB-IP and T-DMB signals are processed according to the original DAB standard. For T-MMB signals, because the channel coding method added in this embodiment may be adopted at the transmitting end, when performing channel and source decoding on these two types of signals, it is necessary to set control information of a coding scheme in advance, extract control information of a corresponding coding scheme in the FIC channel, and perform corresponding channel and source decoding according to the identified source and channel coding scheme. Specifically, in this embodiment, according to the source and channel coding scheme identified by the transmitting end according to fig. 8, and also according to fig. 8, the content of the corresponding field is extracted, the source and channel coding scheme is analyzed, and channel and source decoding is performed.

When the sending end includes the process of conditional access scrambling, energy diffusion and time interleaving, the receiving end also extracts the service data and then carries out time deinterleaving, channel decoding, energy de-diffusion, conditional access descrambling and information source decoding on the data on each sub-channel in sequence.

The receiving method flow of the T-MMB compatible with DAB is finished corresponding to the sending method in the embodiment of the invention. In fact, for the DAB, DAB-IP and T-DMB signals in the transmission data of the present invention, since the three types of signals are performed according to their original standards during the process of coding and modulating, the respective signals can be successfully received by the DAB receiving method, DAB-IP receiving method and T-DMB receiving method, and then the normal play after demodulation and decoding can be performed. And the receiving party can normally receive four signals including DAB, DAB-IP, T-DMB and T-MMB and correspondingly demodulate, decode and play the signals according to the receiving party rule of the invention.

The above is a specific implementation manner of the T-MMB transmission and reception method compatible with DAB in the embodiments of the present invention, which can achieve the purpose of efficiently transmitting multiple service data, and is suitable for mobile reception and has good frequency point availability.

In this embodiment, the sending method may be implemented in a specific transmitter, and the transmitter may transmit the formed multimedia service signal to cover a certain area, and a corresponding receiver in the area may receive the multimedia service signal by using the receiving method. The transmitters and the receivers can be flexibly networked, and can be formed into a multi-frequency network (MFN) or a single-frequency network (SFN), thereby forming a T-MMB transmission system compatible with DAB. The following describes a specific implementation of the DAB-compatible T-MMB transmission system in the present invention, taking the single frequency network as an example.

Fig. 14 is a specific structural diagram of a DAB-compatible T-MMB system in the embodiment of the present invention. As shown in fig. 14, the system includes: a broadcaster or Network Control Center (NCC)1410, more than one transmitting station 1420 located in different regions, which may be local broadcasters or regional transmitting base stations, more than one receiver 1430.

Thus, an integrated terrestrial mobile multimedia broadcasting network can be formed, and the broadcasting network in the embodiment is a single frequency network. The transmitting station 1420 receives a plurality of digital multimedia broadcasting (program) signals, which may include a DAB signal, a DAB-IP signal, a T-DMB signal and a T-MMB signal, from a certain broadcasting station or a network control center 1410, performs source coding and channel coding on the signals, and embeds the coded data in a main service channel MSC of the DAB system in a time division multiplexing manner; correspondingly identifying the service type, the occupied sub-channel information and the coding modulation mode corresponding to the service data signal in a Fast Information Channel (FIC), and carrying out channel coding on data in the FIC channel; and carrying out channel modulation on the data of the FIC channel and the MSC channel according to the determined transmission mode and the channel modulation mode, carrying out OFDM modulation and radio frequency modulation on the data of the FIC channel and the MSC channel after the channel modulation and the data of the synchronous channel, and then transmitting the data. The transmitted signals are transmitted to a terrestrial mobile receiver or portable receiver 1430, such as a mobile phone television, using terrestrial waves. A receiver 1430 for performing radio frequency demodulation, OFDM demodulation, and synchronization on the received radio frequency signal; and then extracting service data in the sub-channels of the corresponding service types according to control information of the FIC channel obtained after channel demodulation and channel decoding, and sequentially performing channel demodulation, channel decoding and information source decoding on the extracted service data according to the coding mode of the corresponding service types in the FIC channel.

The user receiver 1430 within the coverage area may be a DAB receiver, a DAB-IP receiver, a T-DMB receiver and a T-MMB receiver, but also coverage depends on many factors, such as terrain, tower height and power, receiver antenna and gain/directivity, etc., so that the signal received by the user has not only a direct signal, but also a signal that has undergone one or more reflections, and signals transmitted by remote transmitters in a multi-frequency network or a co-frequency network, there is a problem of multipath interference, and, in addition, for a mobile receiver, there is a doppler effect, and therefore, the transmission channel is modeled as a time-varying multipath channel, and since the present invention adopts the DAB system structure, the design of the transmission layer is customized for the time-varying multipath channel, so that the T-MMB transmission system supports mobile reception and SFN networking.

The most basic transmitting station comprises a receiving module, a source coding module, a channel multiplexing module and a modulation transmitting module. In the embodiment, the system further comprises a conditional access scrambler, an energy diffuser and a time interleaver. Specifically, the structure of the transmitting station 1420 is shown in fig. 15. The transmitting station 1420 includes a receiving module 1421, a source coding module 1422, a conditional access scrambler 1423, an energy spreader 1424, a channel coding module 1425, a time interleaver 1426, an FIC data forming module 1427, a channel multiplexing module 1428, and a modulation transmitting module 1429.

In the transmitting station 1420, a receiving module 1421 is used for receiving multiple channels of digital multimedia broadcasting (program) signals from a certain broadcasting station or the network control center 1620 and forwarding the signals to a source coding module 1422; these signals may include a DAB signal, a DAB-IP signal, a T-DMB signal, and a T-MMB signal.

A source coding module 1422, configured to perform source coding on the signal forwarded by the receiving module 1421 according to the service type of the signal, and then send the coding result to the conditional access scrambler 1423. A conditional access scrambler 1423, configured to perform conditional access scrambling on the received data, and send the result to the energy spreader 1424. An energy spreader 1424, which spreads the energy of the received data and sends the result to a channel coding module 1425. The channel coding module 1425 is configured to perform channel coding on the received signal according to the service type of the signal, specifically according to the channel modulation manner in step 503 shown in fig. 5, and send the result to the time interleaver 1426. A time interleaver 1426, configured to perform time interleaving on the received data, and send the result to a channel multiplexing module 1428. The FIC data forming module 1427 is configured to identify a service type, occupied sub-channel information, a source coding scheme, a channel coding scheme, and a channel modulation scheme corresponding to the service data in the FIC, perform channel coding on the data in the FIC channel, and send a coding result to the channel multiplexing module 1428. The channel multiplexing module 1428 inserts the signal into the MSC in a time division multiplexing manner according to the service type, and multiplexes the data of the MSC channel and the FIC coding result sent by the FIC data forming module 1427, and sends the result to the modulation sending module 1429. And a modulation sending module 1429, configured to perform channel modulation on the received FIC channel and MSC channel data according to the determined transmission mode and channel modulation mode, perform OFDM modulation on the channel modulated FIC channel and MSC channel data and data of the synchronization channel, and modulate the result to a predetermined working frequency point to send the result.

The DAB receiver, the DAB-IP receiver and the T-DMB receiver can smoothly receive respective signals and carry out normal playing after demodulation and decoding. Here, the structure of the T-MMB receiver is described in detail. Fig. 16 is a specific structural diagram of a T-MMB receiver in the embodiment of the present invention. The receiving end mainly comprises four steps of reverse sequence and reverse process with the transmitting end, namely: radio frequency demodulation, baseband demodulation, channel decoding and source decoding. Specifically, the T-MMB receiver 1430 includes a reception demodulation module 1431, an FIC data extraction module 1432, a traffic data extraction module 1433, a channel demodulation module 1434, a channel decoding module 1435, and a source decoding module 1436. In addition, since the transmitter station of the present embodiment includes a conditional access scrambler, an energy spreader, and a time interleaver, a time deinterleaver 1437, an energy despreader 1438, and a conditional access descrambler 1439 are also further included in the receiver.

In the receiver 1430, the receiving demodulation module 1431 is configured to receive a signal through an antenna, perform radio frequency demodulation synchronization and OFDM demodulation on the received signal, obtain data of an FIC channel and an MSC channel, and send the data to the FIC data extraction module 1432 and the service data extraction module 1433, respectively. The FIC data extraction module 1432 is configured to perform channel demodulation and channel decoding on the received FIC channel data, and send control information of the FIC to the service data extraction module 1433, the channel demodulation module 1434, the channel decoding module 1435, and the source decoding module 1436.

The service data extracting module 1433 is configured to extract various service data in the MSC according to the control information provided by the FIC, and send the service data to the channel demodulating module 1434. The channel demodulation module 1434 is configured to perform channel demodulation on the received service data according to the determined transmission mode and the channel modulation mode of each type of service data identified in the FIC channel, and send the demodulated data to the time deinterleaver 1437. A time deinterleaver 1437 for time deinterleaving the received data and then transmitting the deinterleaved data to a channel decoding module 1435.

A channel decoding module 1435, configured to perform corresponding decoding on the received signal according to a channel coding manner of the signal identified in the FIC channel, and send the result to the energy despreader 1438. An energy despreader 1438 is configured to despread energy of the received data and send the despread data to the conditional access descrambler 1439. A conditional access descrambler 1439, configured to perform conditional access descrambling on the received data, and send the descrambled data to the source decoding module 1436. A source decoding module 1436, configured to perform source decoding on the received signal according to the service type.

Since the DAB signal and T-DMB signal transmission structures remain unchanged, when the user is a DAB, DAB-IP or T-DMB receiver, the receiver can process the corresponding service signals but cannot process the T-MMB service signals. And the T-MMB receiver can process four service signals of DAB, DAB-IP, T-DMB and T-MMB. Therefore, the T-MMB system is completely compatible with DAB, DAB-IP and T-DMB systems.

The above is a specific structure of the T-MMB transmission system based on the single frequency network in the embodiment of the present invention. Of course, a multi-frequency network can be formed by combining a plurality of single-frequency networks, and in the multi-frequency network, the internal structures of a specific transmitting station and a specific receiver are the same as those in a transmission system of the single-frequency network, but the networking forms are different, and the coverage area is larger. And will not be described in detail herein.

The above is a specific embodiment of the present invention. In the embodiment, it is assumed that the transmission of DAB, DAB-IP, T-DMB and T-MMB signals is performed in the system. In fact, the type of the service data transmitted in the system can be adjusted according to actual needs, and the transmission mode of the selected signal is not changed.

The T-MMB transceiving method and the system of the invention are based on the mature DAB system to expand the multimedia service, on one hand, the DAB system is designed for a handheld mobile terminal, so the invention is also suitable for mobile receiving and displays satisfactory receiving effect; on the other hand, because the control information in the FIC channel expands the description of the relevant information of each sub-service channel, the method and the system of the invention can simultaneously transmit various types of multimedia service data, and overcome the defect of single service of the DAB system; in addition, because the system of the invention expands the channel coding modulation scheme to the original DAB system, the introduced high-efficiency channel modulation scheme, such as 8DPSK and 16QAPSK, overcomes the disadvantage of low frequency band efficiency of the existing DAB system, and the introduced stronger error correction coding scheme, such as LDPC code, provides stronger anti-interference capability for multimedia data, especially video data, so that the whole method and system are more suitable for video program transmission; finally, aiming at the problem of time-varying interference enhancement brought by the adopted efficient channel modulation scheme, the compensation is carried out by shortening the symbol block length of the OFDM, and a good effect is obtained in the actual measurement process, so that the quality requirement of a user on signals is ensured while the frequency band utilization rate is improved.

In a word, compared with the mobile multimedia technology of other systems, the invention has good frequency point availability; the synchronization is simple and easy to realize; the compatibility is good; the frequency band utilization rate is high, and the portable and mobile receiving is supported; the receiver has the advantages of low complexity, easy realization and the like.

The above description is only exemplary of the present invention and should not be taken as limiting the scope of the present invention, and any modifications, equivalents, improvements and the like that are within the spirit and principle of the present invention should be included in the present invention.

Claims (19)

1. A terrestrial mobile multimedia broadcasting transmission method compatible with DAB is characterized in that the service type of multimedia broadcasting is preset, the service type comprises a terrestrial mobile multimedia broadcasting T-MMB service, and the method comprises the following steps:

receiving multimedia broadcasting service data, and sequentially performing source coding and channel coding on the service data according to the service type of the multimedia broadcasting service data;

embedding the coded data into a main service channel MSC of the system in a time division multiplexing mode, correspondingly identifying the service type, occupied sub-channel information, an information source coding mode, a channel coding mode and a channel modulation mode corresponding to the service data in a fast information channel FIC of the system, and carrying out channel coding on the data in the FIC channel;

and carrying out channel modulation on the data of the FIC channel and the MSC channel according to the determined transmission mode and the channel modulation mode, carrying out OFDM modulation and radio frequency modulation on the data of the FIC channel, the MSC channel and the synchronous channel after channel modulation, and then sending out the data.

2. The method of claim 1,

between the information source coding and the channel coding of the received service data, further comprising the steps of carrying out conditional access scrambling and energy diffusion on the data after the information source coding in sequence; and further comprises time interleaving the channel-coded data after the channel coding and before the time division multiplexing.

3. The method according to claim 1 or 2, wherein when the service type is T-MMB service, the channel coding is performed on the service data by using a concatenated code or a low density parity check, LDPC, code.

4. The method according to claim 1 or 2, characterized in that the channel modulation is performed on the T-MMB service data in the transmission frame by using 4-point differential phase shift keying DQPSK, 8-point differential phase shift keying 8DPSK, 16-point differential amplitude and phase joint keying 16DAPSK, or 64-point differential amplitude and phase joint keying 64 DAPSK.

5. The method as claimed in claim 1, wherein the size of the corresponding capacity unit CU in the MSC is determined according to the channel modulation method of the service data when the encoded data is embedded in the main service channel MSC of the DAB system in a time division multiplexing manner.

6. The method of claim 5, wherein the determining the size of the corresponding CU in the MSC is: n × 32bits, where n ═ 2 represents a service data DQPSK modulation mode, n ═ 3 represents that the service data adopts an 8DPSK modulation mode, n ═ 4 represents that the service data adopts a 16DAPSK modulation mode, n ═ 5 represents that the service data adopts a 32DAPSK modulation mode, and n ═ 6 represents that the service data adopts a 64DAPSK modulation mode.

7. The method of claim 1, wherein the correspondingly identifying the service type, the occupied sub-channel information, the source coding scheme, the channel coding scheme, and the channel modulation scheme corresponding to the service data in a Fast Information Channel (FIC) of the system is:

the method comprises the steps of establishing an FIG of an FIC channel of a T-MMB system based on a quick information group FIG of the FIC channel of the DAB system, and identifying a service type, occupied sub-channel information, an information source coding mode, a channel coding mode and a channel modulation mode corresponding to service data in the FIG of the FIC channel of the T-MMB system.

8. The method of claim 7, wherein when the service type is T-MMB service, the service type corresponding to the service data identified in FIG of the FIC channel of the T-MMB system is: adding the service type description of the T-MMB system in the data service component type field in the FIG type 0/the extended mode 2 of the FIC channel of the T-MMB system; and adding the Application description of the T-MMB User in the field of the User Application Type in the FIG Type 0/extended mode 13 of the FIC channel of the T-MMB system.

9. The method of claim 7, wherein when the service type is T-MMB service, the sub-channel information identifying the service data occupation in FIG of the FIC channel of the T-MMB system is: adding a sub-channel identification field in the FIG of the FIC channel of the T-MMB system for identifying the sub-channel occupied by the service data; a start address field is added to the FIG of the FIC channel of the DAB system for identifying the address of the first CU of a sub-channel.

10. The method of claim 7, wherein when the service type is T-MMB service, the channel coding scheme and the channel modulation scheme for identifying service data in FIG of the FIC channel of the T-MMB system are:

adding a coding type field in the FIG of the FIC channel of the T-MMB system for identifying a channel coding mode of the T-MMB service;

adding a Sub-channel data area Sub-channel field in the FIG of the FIC channel of the T-MMB system, wherein the Sub-channel data area Sub-channel field is used for identifying the size of the Sub-channel of the T-MMB service and the protection level of the adopted error correction coding;

and adding a modulation type ModuType field in the FIG of the FIC channel of the T-MMB system for identifying the channel modulation mode of the T-MMB service.

11. The method of claim 1, wherein the determining the transmission mode is:

and determining the transmission mode according to the adopted channel modulation mode and the working frequency point appointed by the system by referring to the corresponding relation among the preset channel modulation mode, the transmission mode and the working frequency point.

12. The method of claim 11,

when the channel modulation mode is m-DPSK or m-DAPSK, if the working frequency point of the T-MMB is BandIII, adopting a transmission mode IV, and if the working frequency point of the T-MMB is L-Band, adopting a transmission mode III; m is one or any combination of 16, 32 or 64;

and when the channel modulation mode is DQPSK, if the working frequency point of the T-MMB is BandIII, adopting a transmission mode I, and if the working frequency point of the T-MMB is L-Band, adopting a transmission mode II.

13. A DAB-compatible terrestrial mobile multimedia broadcasting receiving method, comprising:

performing radio frequency demodulation, OFDM demodulation and synchronization on the received signals to obtain data of an FIC channel and an MSC channel, and judging an adopted transmission mode;

sequentially carrying out channel demodulation and channel decoding on the data of the FIC channel, and extracting service data in the sub-channel of the corresponding service type in the MSC channel according to the control information of the FIC channel;

and according to the judged transmission mode and the channel modulation, channel coding and source coding modes of various service data identified in the FIC channel, sequentially carrying out channel demodulation, channel decoding and source decoding on the extracted service data.

14. The method of claim 13, wherein the discriminant transmission mode is:

and judging the transmission mode according to the adopted channel modulation mode and the working frequency point appointed by the system by referring to the corresponding relation between the preset channel modulation mode and the transmission mode and the working frequency point.

15. A DAB-compliant terrestrial mobile multimedia broadcasting system, comprising: a Network Control Center (NCC), a transmitting station, and a receiver, wherein,

the NCC is used for sending the multimedia broadcast service data to the transmitting station;

the transmitting station is used for receiving the multimedia broadcast service data from the NCC, performing source coding and channel coding on the multimedia broadcast service data according to the service type of the multimedia broadcast service data, embedding the coded data into the MSC of the system in a time division multiplexing mode, correspondingly marking the service type corresponding to the service data, the occupied sub-channel information, the source coding mode, the channel coding mode and the channel modulation mode in the fast information channel FIC, and performing channel coding on the data in the FIC channel; the system is also used for carrying out channel modulation on the data of the FIC channel and the MSC channel according to the determined transmission mode and the channel modulation mode, carrying out OFDM modulation and radio frequency modulation on the data of the FIC channel and the MSC channel after the channel modulation and the data of the synchronous channel, and transmitting the data to the receiver in the system;

the receiver is used for performing radio frequency demodulation, OFDM demodulation and synchronization on the received radio frequency signals sent by the transmitting station; and extracting service data in the sub-channels of the corresponding service types according to control information of the FIC channel obtained after channel demodulation and channel decoding, and performing channel demodulation, channel decoding and information source decoding.

16. The system of claim 15, wherein the transmitting station comprises a receiving module, a source coding module, a channel coding module, a FIC data forming module, a channel multiplexing module, and a modulation transmission module, wherein,

the receiving module is used for receiving the multimedia broadcast service data from the NCC and forwarding the service data to the information source coding module;

the signal source coding module is used for carrying out signal source coding on the signal forwarded by the receiving module according to the service type of the service data and then sending a signal source coding result to the channel coding module;

the channel coding module is used for carrying out channel coding on the received data and sending the result to the channel multiplexing module;

the FIC data forming module is used for correspondingly identifying the service type, the occupied sub-channel information, the information source coding mode, the channel coding mode and the channel modulation mode corresponding to the service data in the FIC, carrying out channel coding on the data in the FIC channel, and sending the coding result to the channel multiplexing module;

the channel multiplexing module is used for inserting the received service data into an MSC channel in a time division multiplexing mode according to the service type, multiplexing the data of the MSC channel and the FIC coding result sent by the FIC data forming module and then sending the result to the modulation sending module;

and the modulation sending module is used for carrying out channel modulation on the data of the received FIC channel and the data of the received MSC channel according to the determined transmission mode and the determined channel modulation mode, carrying out OFDM modulation and radio frequency modulation on the data of the FIC channel and the data of the MSC channel after the channel modulation and the data of the synchronous channel, and sending the data to the receiver.

17. The system of claim 16, wherein the transmitting station further comprises a conditional access scrambler, an energy spreader, and a time interleaver, wherein,

the source coding module is used for sending a source coding result to the conditional access scrambler;

the conditional access scrambler is used for performing conditional access scrambling on the received data and then sending the data to the energy diffuser;

the energy diffuser is used for transmitting the received data to the channel coding module after energy diffusion;

the channel coding module is used for sending the result after channel coding to the time interleaver;

the time interleaver is configured to time interleave the received data and send the interleaved data to the channel multiplexing module.

18. The system according to any one of claims 15 to 17, wherein the receiver is: one or any combination of DAB receiver, DAB-IP receiver, digital multimedia broadcasting T-DMB receiver and T-MMB receiver.

19. The system of claim 18, wherein the T-MMB receiver comprises a receive demodulation module, a traffic data extraction module, a channel decoding module, and a source decoding module, wherein,

the receiving and demodulating module is configured to receive the radio frequency signal sent by the transmitting station, perform radio frequency demodulation, OFDM demodulation, and synchronization on the received signal, obtain data of an FIC channel and an MSC channel, and send the data to the FIC data extracting module and the service data extracting module, respectively;

the FIC data extraction module is used for performing channel demodulation and channel decoding on the received FIC channel data and sending control information of the FIC to the service data extraction module, the channel demodulation module, the channel decoding module and the information source decoding module;

the service data extraction module is used for extracting various service data in the MSC according to the control information provided by the FIC and sending the various service data to the channel demodulation module;

the channel demodulation module is used for carrying out channel demodulation on the received service data according to the distinguished transmission mode and the channel modulation modes of various service data identified in the FIC channel, and sending the demodulated data to the channel decoding module;

the channel decoding module is used for performing corresponding channel decoding on the received signal according to the channel coding mode of the signal identified in the FIC channel, and sending the result to the information source decoding module;

and the information source decoding module is used for carrying out information source decoding on the received signals according to the service types.