CN101883272A - Multi-service Adaptation Method and Implementation Device Based on DTMB Single Frequency Network System - Google Patents

Abstract

The invention discloses a multi-service adaptation method based on a DTMB (Digital Television Terrestrial Multimedia Broadcasting) single-frequency network system, comprising the following steps of: S1. generating a second frame initialization packet at the data stream initial position of a pulse per second by utilizing a GPS reference clock; S2. carrying out standard format matching on new service data in the DTMB single-frequency network system according to the model and the timing sequence mode of the DTMB single-frequency network system to obtain a newly increased equivalent service data packet; and S3. carrying out time division multiplex on the original service data packet, the second frame initialization packet, the newly increased equivalent service data packet and a single-frequency network adaption empty packet in the DTMB single-frequency network system according to the timing sequence mode to obtain single-frequency network multiplex data output. In the invention, the traditional DTMB single-frequency network system is expanded on the basis of not changing the original terrestrial digital television service receipt completely, thereby making the DTMB single-frequency network system compatibly transmit multiple services and broadening the application range of the system.

Description

Multi-service Adaptation Method and Implementation Device Based on DTMB Single Frequency Network System

technical field

The invention relates to the technical field of digital information transmission, in particular to a multi-service adaptation method based on a DTMB single frequency network system in a wireless or wired broadcast communication system and a device for realizing it.

Background technique

In the past two decades, with the rapid development of modern communication technology, the proprietary communication system for transmitting various services has become the most basic communication system for existing single services because of its strong pertinence, and has been widely used in wireless local area networks, wireless Or communication systems such as cable digital audio and video broadcasting, for example, the European digital TV terrestrial broadcasting standard and the Chinese digital TV terrestrial broadcasting single frequency network system, etc.

China's Digital Television Terrestrial Multimedia Broadcasting (DTMB) single-frequency network system is a typical representative of the existing single-service multi-transmitter system, and the structure of the sending end is shown in Figure 1. The input single service data stream is first input to the SFN adapter for adaptation to form a standard data packet stream containing the Second Initial Packet (SIP); then it is sent to each transmitting station through the SFN program distribution network ; Then each transmitting station passes through the scrambler (randomization), forward error correction coding (Forward Error Correction, FEC), and then carries out the constellation mapping from the bit stream to the symbol stream, and then forms the basic data block after interleaving ; After the basic data block and system information are combined and multiplexed, the frame body is formed through frame body data processing, and the frame body and the corresponding frame header (Pseudo-random Noise, PN sequence) are multiplexed into a signal frame, which is converted into a signal frame after baseband post-processing The baseband output signal within the 8MHz bandwidth; finally, it is converted into a radio frequency signal within the UHF and VHF frequency bands by quadrature up-conversion for transmission.

As people's demand for wireless communication system transmission combined with voice, data, video, image and other services increases, it is of great significance to provide users with the services they need, which will inevitably promote the use of limited resources to provide users with a variety of services. business research. For example, the multi-service transmission system realized by improving the transmitter based on the American Advanced Television System Committee (Advanced Television System Committee, ATSC) standard (see literature S.Kim, J.Lee, S.Kim, et al., "Enhanced -xVSB system development for improving ATSC terrestrial DTV transmission standard," IEEE Trans.Broadcasting, vol.52, no.2, pp.129-136, 2006.), compatible with multi-service European second-generation terrestrial digital TV broadcasting (DVB -T2) standard (see document Implementation guidelines for a second generation digital terrestrial television broadcasting system (DVB-T2), ETSI Std., Feb.2009.), embedded multi-service transmission system based on Chinese DTMB standard (see document X.Wang , J. Wang. J. Wang, et al. "Embedded Transmission of Multi-Service over DTMB System," IEEE Trans. Broadcasting, to appear, Sep 2010.).

However, the existing technology does not provide a multi-service transmission system solution based on the Chinese DTMB single frequency network system, the main reason is that in the single frequency network system, multi-service is often caused by the proprietary nature of the single frequency network adapter Compatible transmission cannot be achieved due to the mismatch of data format and transmission rate. The main function of the DTMB single frequency network adapter is to insert a SIP into the data stream at each second pulse position of the GPS according to the system output code rate clock (wherein, as shown in Figure 2, the SIP packet consists of a 4-byte header and a 184 In other positions, the data code stream is read from the front buffer, and if the data is less than one standard data packet, an empty packet for SFN adaptation is automatically inserted (as shown in Figure 3) Complete the code rate adaptation of the data stream. Since single frequency network systems already exist widely, redesigning the entire system will waste a lot of valuable system resources. Therefore, the key to supporting multi-service adaptation based on the Chinese DTMB single frequency network system is: how to A single frequency network multi-service adaptation method and implementation device are redesigned.

Contents of the invention

(1) Technical problems to be solved

The technical problem to be solved by the present invention is to solve the problem that the existing DTMB single frequency network adapter cannot be compatible with multi-format service transmission without changing the traditional digital television receiver at all.

(2) Technical solution

For solving the problems of the technologies described above, the technical solution of the present invention provides a kind of multi-service adaptation method based on the DTMB single frequency network system, comprising the following steps:

S1: Use the GPS reference clock to generate a second frame initialization packet at the initial position of the data stream of each second pulse;

S2: Perform standard format matching on the newly added service data in the DTMB single frequency network system according to the system mode and timing mode of the DTMB single frequency network, and obtain an equivalent newly added service data packet;

S3: Perform time-division multiplexing on the original service data packets, second frame initialization packets, equivalent new service data packets and single frequency network adaptation empty packets in the DTMB single frequency network system according to the timing method, to obtain a single frequency Network multiplexing data stream output.

Wherein, the following steps are also included before step S2: S11: input the original business data packet in the DTMB single frequency network system; S12: input the new business data in the DTMB single frequency network system, the new business data is the preprocessed data; wherein, the order of step S1, step S11 and step S12 can be interchanged.

In step S2, the preprocessing includes one or any combination of randomization, channel coding, interleaving and bit multiple expansion operations. The standard format matching includes inserting service identification codes and matching data.

In the time-division multiplexing process of step S3, if the data is less than one standard data packet, insert the SFN adaptation empty packet to complete the code rate adaptation of the data stream. The single frequency network multiplexing data flow includes the original service data packet, the second frame initialization packet, the equivalent new service data packet and the single frequency network adaptation empty packet, and the second frame initialization packet occupies every second The initial packet position of the burst's data stream.

Time-division multiplexing is performed in the standard data packet format used for standard format matching according to the timing manner.

Wherein, the system mode is a modulation and/or coding mode; the timing mode is the timing position of the insertion position of the second frame initialization packet in the new service preprocessing data or the original service data packet; the The above standard data package is one of MPEG-2, AVS, H.264.

The present invention also provides a device for implementing the above multi-service adaptation method, including:

The second frame initialization packet generation module is used to generate the second frame initialization packet at the initial position of the data stream of each second pulse according to the GPS reference clock;

Multi-service format matching module, for carrying out described standard format matching to the newly-increased service data in the input DTMB single-frequency network system according to the system pattern and timing mode that control module sends, output described equivalent newly-increased service data packet;

The multiplexing module is used to time-division multiplex the original service data packet, second frame initialization packet, equivalent new service data packet and single frequency network adaptation empty packet according to the timing method, to obtain a single frequency network Multiplexing data stream output;

The control module is used to control the standard format matching mode in the multi-service format matching module and the time division multiplexing mode in the multiplexing module.

Wherein, the control module simultaneously adjusts in combination with the standard format matching mode in the multi-service format matching module and the time division multiplexing mode in the multiplexing module.

(3) Beneficial effects

The present invention expands the existing single frequency network adapter in the DTMB single frequency network system on the basis of not changing the traditional digital television receiver at all, so that the adapter can be embedded with multiple services and expands the application of the DTMB single frequency network system Range, and the spectrum is used reasonably, saving system resources.

Description of drawings

Fig. 1 is the structural representation of DTMB single frequency network system transmitting end in the prior art;

Fig. 2 is the SIP structural representation of DTMB single frequency network system in the prior art;

Fig. 3 is the empty packet format schematic diagram of DTMB single frequency network system in the prior art;

Fig. 4 is the method flowchart of the embodiment of the present invention;

Fig. 5 is a schematic diagram of the device structure of an embodiment of the present invention;

6 is a schematic diagram of a frame structure of multiplexed data in Embodiment 1 of the present invention;

7 is a schematic diagram of a frame structure of multiplexed data in Embodiment 2 of the present invention;

FIG. 8 is a schematic diagram of a frame structure of multiplexed data in Embodiment 3 of the present invention.

Detailed ways

In order to make the purpose, content, and advantages of the present invention clearer, the implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings.

As shown in Figure 4, the multi-service adaptation method based on the DTMB single frequency network system according to the embodiment of the present invention includes steps:

S1: Input the original service data packet in the DTMB system;

Wherein, the original service data packets are, but not limited to, standard data packets such as MPEG-2, AVS, and H.264.

S2: Input new business data, and preprocess the data to obtain new business preprocessing data;

Wherein, the preprocessing includes operations such as randomization, channel coding, interleaving, and bit multiple expansion, or a combination thereof.

S3: Utilize the GPS reference clock to generate a second frame initialization packet at the initial position of the data stream of each second pulse;

Wherein, the order of step S1, step S2 and step S3 can be interchanged.

S4: According to the system mode and timing mode of the DTMB single frequency network, perform standard format matching on the pre-processed data of the new service to obtain an equivalent new service data packet;

Wherein, standard format matching includes inserting a service identification code and matching data, wherein the relationship between the service identification code and the matching data includes a definite relationship, an indeterminate relationship or a combination thereof.

Wherein, if the system mode and timing mode are different, the standard format matching method is also different.

Wherein, the equivalent new service data packets are, but not limited to, standard data packets such as MPEG-2, AVS, H.264, etc.

S5: Perform time-division multiplexing on the second frame initialization packet, the equivalent new service data packet, the original service data packet, and the single frequency network adaptation empty packet (hereinafter referred to as the empty packet) according to the timing method, to obtain the single frequency network multiplex Output with data stream.

Among them, in the process of time division multiplexing, if the data is less than one standard data packet, an empty packet is inserted to complete the code rate adaptation of the data stream, and the empty packet is, but not limited to, standard data packets such as MPEG-2, AVS, and H.264 .

Among them, the single frequency network multiplexing result includes the second frame initialization packet, the equivalent new service data packet, the original service data packet and the empty packet, and the second frame initialization packet occupies the initial stage of the data flow of each GPS pulse per second. Location.

As shown in Figure 5, the present invention also provides a device for implementing the above multi-service adaptation method, including:

The second frame initialization packet generation module is used to generate a second frame initialization packet at the initial position of the data stream of each second pulse according to the GPS reference clock;

The multi-service format matching module is used to perform the standard format matching on the input new service preprocessing data according to the system mode and timing mode sent by the control module, and output the equivalent new service data packet;

The multiplexing module is used to time-division multiplex the original service data packet, the second frame initialization packet, the equivalent new service data packet and the single frequency network adaptation empty packet according to the timing method to obtain the single frequency network Multiplexing data stream output;

The control module is used to control the standard format matching mode in the multi-service format matching module and the time division multiplexing mode in the multiplexing module.

Embodiments of the present invention are illustrated below. For the convenience of description, some definitions and concepts used below are firstly defined and explained.

TS packet: that is, the transmission data packet. The information source coding part of the existing DTMB single frequency network system usually adopts the MPEG-2, H.264 or AVS standard. Taking the MPEG-2 standard as an example, its transmission code stream is based on TS packets, and the size of each TS packet is 188 bytes, that is, 188*8=1504 bits. In the following embodiments, the input TV service data packets, equivalent mobile service data packets and second frame initialization packets all use 188-byte MPEG-2TS packets.

Frame: The input TS packet is a data symbol block with a length of 3744 symbols formed after randomization, forward error correction coding, and constellation mapping in the DTMB standard. According to the DTMB standard, the number of TS packets contained in a frame is shown in Table 1 under different modulation and coding conditions.

Table 1

Example 1

This embodiment proposes a multi-service adaptation method. In the present embodiment, the DTMB single frequency network system terrestrial digital TV service (hereinafter referred to as the TV service) adopts the encoding method in the DTMB system: FEC0.8 (7488, 6016), the modulation method: 16QAM; the newly added mobile service ( Hereinafter referred to as the mobile service) is preprocessed by randomization in the DTMB system, FEC0.4 (7488, 3008) encoding, bit interleaving, and 2 times bit extension from 4QAM to 16QAM; the insertion position of the second frame initialization TS packet is located in the mobile In the business frame. The service adaptation method in this embodiment specifically includes the following steps:

S101: Input 8 TV service TS packets;

S102: Input a data block with a length of 3008 bits for the mobile service, and after preprocessing such as randomization, FEC0.4 (7488, 3008) encoding, bit interleaving, and 2 times bit extension from 4QAM to 16QAM, a 7488*2-bit data block is obtained data block;

S103: the strobe second frame initialization packet generation module 101 utilizes the GPS code rate clock to generate a second frame initialization TS packet at the data stream position of each second pulse;

S104: According to the system mode of 16QAM modulation/FEC0.8 (7488, 6016) code sent by the control module 104 and the second frame initialization TS packet insertion position is located at the timing position in the mobile service frame, the mobile service preprocessing data strobe is input to The multi-service format matching module 102 obtains an equivalent new service TS package, that is, performs data block matching with a code length of 7488*2 bits to obtain a 6016*3 bit data block, which is equivalent to 12 equivalent new service TS packages;

S105: The insertion position of the second frame initialization TS packet sent by the control module 104 is located at the timing position in the mobile service frame, and the second frame initialization TS packet, the equivalent new service TS packet, the TV service TS packet and the empty packet are time-division multiplexed Use to get 2 frames of multiplexed data, as shown in Figure 6.

Example 2

This embodiment proposes another multi-service adaptation method. In the present embodiment, the terrestrial digital television service of the DTMB single frequency network system (hereinafter referred to as the television service) adopts the encoding method in the DTMB system: FEC0.6 (7488, 4512), and the modulation method: 64QAM; Mobile service for short) is set to have undergone preprocessing such as randomization in the DTMB system, FEC0.8 (7488, 6016), bit interleaving, and 3 times bit expansion from 4QAM to 64QAM; the insertion position of the second frame initialization TS packet is located in the mobile service frame middle. The service adaptation method in this embodiment specifically includes the following steps:

S201: Input 9 TV service TS packets;

S202: Input a data block with a mobile service length of 6016 bits, and obtain 7488*3 bits of data after preprocessing such as randomization, FEC0.4 (7488, 3008) encoding, bit interleaving, and 3 times bit extension from 4QAM to 64QAM piece;

S203: The strobe second frame initialization packet generation module 101 utilizes the GPS code rate clock to generate a second frame initialization TS packet at the initial position of the data stream of each second pulse;

S204: According to the system mode of 64QAM modulation/FEC0.6 (7488, 4512) encoding sent by the control module 104 and the insertion position of the second frame initialization TS packet is located at the timing position in the mobile service frame, input the mobile service preprocessing data strobe Go to the multi-service format matching module 102 to obtain an equivalent new service TS package, that is, to match a data block with a code length of 7488*3 bits to obtain a 4512*6 bit data block, which is equivalent to 18 equivalent new service TS packages ;

S205: According to the insertion position of the second frame initialization TS packet sent by the control module 104 at the timing position in the mobile service frame, perform time division multiplexing on the second frame initialization TS packet, the equivalent new service TS packet, the TV service TS packet and the empty packet Use to get 2 frames of multiplexed data, as shown in Figure 7.

Example 3

This embodiment proposes a multi-service adaptation method according to an implementation manner of the present invention. In the present embodiment, the terrestrial digital television service of the DTMB single frequency network system (hereinafter referred to as the television service) adopts the encoding method in the DTMB system: FEC0.6 (7488, 4512), and the modulation method: 64QAM; Mobile service for short) is set to have undergone preprocessing such as randomization in the DTMB system, FEC0.8 (7488, 6016), bit interleaving, and 3 times bit expansion from 4QAM to 64QAM; the second frame initialization TS packet insertion position is located in the TV service frame . The service adaptation method in this embodiment specifically includes the following steps:

S301: Input 9 TV service TS packets;

S302: Input a data block with a mobile service length of 6016 bits, and after preprocessing such as randomization, FEC0.4 (7488, 3008) encoding, bit interleaving, and 3 times bit extension from 4QAM to 64QAM, the data of 7488*4 bits is obtained piece;

S303: the strobe second frame initialization packet generation module 101 utilizes the GPS code rate clock to generate a second frame initialization TS packet at the data stream position of each second pulse;

S304: According to the system mode of 64QAM modulation/FEC0.6 (7488, 4512) encoding sent by the control module 104 and the insertion position of the second frame initialization TS packet is located at the timing position in the mobile service frame, input the mobile service preprocessing data strobe To the multi-service format matching module 102 to obtain the equivalent new business TS package, that is, the data block with a code length of 7488*3 bits is matched to the data block of 4512*6 bits, which is equivalent to 18 equivalent new business TS packages;

S305: According to the insertion position of the second frame initialization TS packet sent by the control module 104 at the timing position in the TV service frame, perform time division multiplexing on the second frame initialization TS packet, the equivalent new service TS packet, the TV service TS packet and the empty packet , to obtain 2 frames of multiplexed data, as shown in FIG. 8 .

The above embodiments are only used to illustrate the present invention, but not to limit the present invention. Those of ordinary skill in the relevant technical field can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all Equivalent technical solutions also belong to the category of the present invention, and the scope of patent protection of the present invention should be defined by the claims.

Claims (10)

1. a kind of multi-service adaptation method based on DTMB single frequency network system, is characterized in that, comprises the following steps: S1: Use the GPS reference clock to generate a second frame initialization packet at the initial position of the data stream of each second pulse; S2: Perform standard format matching on the newly added service data in the DTMB single frequency network system according to the system mode and timing mode of the DTMB single frequency network, and obtain an equivalent newly added service data packet; S3: Perform time-division multiplexing on the original service data packet, second frame initialization packet, equivalent new service data packet and single frequency network adaptation empty packet in the DTMB single frequency network system according to the timing method, to obtain a single frequency Network multiplexing data stream output. 2. The multi-service adaptation method according to claim 1, further comprising the following steps before step S2: S11: Input the original service data packet in the DTMB single frequency network system; S12: Input new business data in the DTMB single frequency network system, the new business data is data after preprocessing; Wherein, the order of step S1, step S11 and step S12 can be interchanged. 3. The multi-service adaptation method according to claim 2, wherein in step S12, the preprocessing includes one or any combination of randomization, channel coding, interleaving and bit multiple expansion operations. 4. The multi-service adaptation method according to claim 1, wherein in step S2, the standard format matching includes inserting service identification codes and matching data. 5. The multi-service adaptation method according to claim 1, characterized in that, in the time division multiplexing process in step S3, if the data is less than one standard data packet, then insert the empty packet completion data for the SFN adaptation Stream rate adaptation. 6. The multi-service adaptation method according to claim 1, wherein in step S3, the single frequency network multiplexed data flow includes the original service data packet, second frame initialization packet, equivalent new The service-increasing data packet and the SFN adaptation empty packet, and the second frame initialization packet occupies the initial data packet position of the data flow of each pulse per second. 7. The multi-service adaptation method according to claim 1, wherein in step S3, the time division multiplexing is performed in the standard data packet format used for standard format matching according to the timing method. 8. The multi-service adaptation method according to claim 7, wherein the system mode is a modulation and/or coding mode; the timing mode is that the insertion position of the second frame initialization packet is in the newly added The timing position in the service preprocessing data or the original service data packet; the standard data packet is one of MPEG-2, AVS, and H.264. 9. A device for implementing the multi-service adaptation method according to any one of claims 1 to 8, characterized in that it comprises: The second frame initialization packet generation module is used to generate the second frame initialization packet at the initial position of the data stream of each second pulse according to the GPS reference clock; Multi-service format matching module, for carrying out described standard format matching to the newly-increased service data in the input DTMB single-frequency network system according to the system pattern and timing mode that control module sends, output described equivalent newly-increased service data packet; The multiplexing module is used to time-division multiplex the original service data packet, second frame initialization packet, equivalent new service data packet and single frequency network adaptation empty packet according to the timing method, to obtain a single frequency network Multiplexing data stream output; The control module is used to control the standard format matching mode in the multi-service format matching module and the time division multiplexing mode in the multiplexing module. 10. The device according to claim 9, wherein the control module simultaneously adjusts in combination with the standard format matching mode in the multi-service format matching module and the time division multiplexing mode in the multiplexing module.

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