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CN-120050149-B - Analysis method and device of DTMB-A single frequency network system

CN120050149BCN 120050149 BCN120050149 BCN 120050149BCN-120050149-B

Abstract

The application relates to an analysis method and A device of A DTMB-A single-frequency network system, wherein the method comprises the steps of generating MIP packets according to A pre-transmitting mode and GPS information of the DTMB-A, inserting the MIP packets into pre-transmitted service datA, simultaneously calculating the number of the service datA packets and zero padding quantity contained in each OFDM frame according to the pre-transmitting mode to obtain service datA streams which are completely matched with the DTMB-A transmitting net code rate, receiving the service datA streams and control information through each transmitting station, taking each MIP packet in the service datA streams as A first datA packet of an OFDM frame, extracting A time tag and A maximum time delay of A channel in the MIP packets to calculate additional time delay, modulating the service datA streams and the control information, generating A multi-frame synchronous channel according to the additional time delay, multiplexing the datA frame information and the control frame information, generating radio frequency signals corresponding to multiplexing signals, and broadcasting the radio frequency signals and transmitting the radio frequency signals. Therefore, the problems that the current single-frequency network adapter cannot meet the requirement of A single-frequency network of A DTMB-A system and the like are solved.

Inventors

  • SUN YONGLE
  • SONG JIAN
  • ZHANG CHAO

Assignees

  • 清华大学

Dates

Publication Date
20260512
Application Date
20250109

Claims (10)

  1. 1. The analysis method of the DTMB-A single-frequency network system is characterized by comprising the following steps of: Generating MIP packets according to A pre-transmitting mode and GPS information of A target DTMB-A single-frequency network system, inserting the MIP packets into pre-transmitted service datA, and simultaneously calculating the number of the service datA packets and the zero padding quantity contained in each OFDM frame according to the pre-transmitting mode to obtain service datA streams which meet the preset matching requirement with the DTMB-A transmission net code rate; Receiving the service datA stream and the control information through preset transmitting stations, taking each MIP packet in the service datA stream as A first datA packet of an OFDM frame in the target DTMB-A single-frequency network system, and extracting A time tag and A channel maximum delay in the MIP packet so as to calculate additional delay according to the time tag and the channel maximum delay; Preprocessing the service data stream and the control information, scrambling, encoding, constellation mapping and symbol interleaving the preprocessed service data stream and the preprocessed control information to obtain corresponding data processing results, and performing OFDM modulation and frequency grouping on the data processing results and a preset PN-MC sequence to generate data frame information corresponding to the service data stream and control frame information corresponding to the control information; Generating a multi-frame synchronous channel through the additional delay, multiplexing the data frame information and the control frame information by utilizing the multi-frame synchronous channel to synthesize a multi-frame so as to obtain a corresponding multiplexing signal, and converting the multiplexing signal into a radio frequency signal of a radio frequency band so as to synchronously broadcast and transmit the radio frequency signal.
  2. 2. The method of claim 1, wherein the generating MIP packets according to the pre-transmission mode and GPS information of the target DTMB-A single frequency network system, inserting the MIP packets in the pre-transmitted service datA, and calculating the number of service datA packets and the zero padding number included in each OFDM frame according to the pre-transmission mode to obtain A service datA stream with A net code rate meeting A preset matching requirement, includes: Determining A plurality of target frames which correspond to the target DTMB-A single-frequency network system and meet the requirement of A preset TS packet, and inserting one MIP packet into A corresponding MPEG-2 transport stream every other target frame, wherein the one target frame comprises N TS packets, the value of N is adjusted according to the transmission rate of A TS code stream, and N is an integer; Determining A working mode of the target DTMB-A single-frequency network system and an OFDM frame corresponding to each target frame in the target frames according to the target frames, and performing zero padding operation on the tail of service datA pre-sent in each OFDM frame according to the working mode in A DTMB-A single-frequency network adapter of the target DTMB-A single-frequency network system to obtain A zero padding MPEG-2 transmission stream; Acquiring length information of each OFDM frame in the zero padding MPEG-2 transport stream, controlling the number of OFDM frames between adjacent MIP packets in the target DTMB-A single-frequency network system to be an integer and the interval between the MIP packets to be less than 1 second according to the length information and the working mode, and controlling A TS code stream to be output in different speed grades according to different modulation modes of the target DTMB-A single-frequency network system through A preset buffer unit.
  3. 3. The method of claim 2, wherein the receiving the service datA stream by each preset transmitting station, taking each MIP packet in the service datA stream as A first datA packet of an OFDM frame in the target DTMB-A single frequency network system, and extracting A time tag and A channel maximum delay in the MIP packet to calculate an additional delay according to the time tag and the channel maximum delay, comprises: Controlling A preset DTMB-A exciter to take each MIP packet in the service datA stream as A first datA packet of an OFDM frame in the target DTMB-A single-frequency network system, and detecting the service datA stream; When detecting MIP packets in the service data stream, acquiring the starting time of OFDM frames corresponding to the MIP packets and the time difference of pps signals generated by a preset global positioning system receiver, and extracting time labels and the maximum time delay of channels from the MIP packets; and calculating the additional delay corresponding to the service data flow based on the time difference, the time tag, the maximum delay of the channel and a preset additional delay calculation strategy.
  4. 4. The method according to claim 1, wherein generating a multiframe synchronization channel by the additional delay, multiplexing the data frame information and the control frame information by using the multiframe synchronization channel to obtain a corresponding multiplexed signal, and converting the multiplexed signal into a radio frequency signal of a radio frequency band for broadcasting the radio frequency signal and transmitting at the same time, comprises: Aligning the datA frame information and the control frame information passing through different network paths according to the additional delay so as to synchronize signal transmitting time in the target DTMB-A single-frequency network system and generate the multi-frame synchronization channel; Multiplexing the data frame information and the control frame information by using the multi-frame synchronous channel to synthesize a multi-frame so as to obtain the multiplexing signal, and performing baseband post-processing on the multiplexing signal so as to generate a baseband transmission signal; And performing quadrature up-conversion operation on the baseband transmission signal to convert the multiplexing signal into a radio frequency signal of a radio frequency band, and performing broadcast time transmission on the radio frequency signal.
  5. 5. A method according to claim 3, wherein the mathematical expression of the additional delay computation strategy is: STS+MD=Measured Delay+Additional Delay wherein STS represents the time tag, MD represents the maximum Delay of the channel, measured Delay represents the time difference, and Additional Delay represents the Additional Delay.
  6. 6. An analysis device of A DTMB-A single frequency network system, comprising: the pre-sending service code stream processing module is used for generating MIP packets according to A pre-sending mode and GPS information of A target DTMB-A single-frequency network system, inserting the MIP packets into pre-sending service datA, and simultaneously calculating the number of the service datA packets and the zero padding number contained in each OFDM frame according to the pre-sending mode so as to obtain A service datA stream which meets the preset matching requirement with the DTMB-A sending net code rate; The receiving module is used for receiving the service datA stream and the control information through preset transmitting stations, taking each MIP packet in the service datA stream as A first datA packet of an OFDM frame in the target DTMB-A single-frequency network system, extracting A time tag and A channel maximum delay in the MIP packet, and calculating additional delay according to the time tag and the channel maximum delay; the modulation module is used for preprocessing the service data stream and the control information, carrying out scrambling, coding, constellation mapping and symbol interleaving on the preprocessed service data stream and the preprocessed control information to obtain corresponding data processing results, and carrying out OFDM modulation and frequency grouping on the data processing results and a preset PN-MC sequence to generate data frame information corresponding to the service data stream and control frame information corresponding to the control information; and the transmitting module is used for generating a multi-frame synchronous channel through the additional delay, multiplexing the data frame information and the control frame information by utilizing the multi-frame synchronous channel to synthesize a multi-frame so as to obtain a corresponding multiplexing signal, and converting the multiplexing signal into a radio frequency signal of a radio frequency band so as to synchronously broadcast and transmit the radio frequency signal.
  7. 7. The apparatus of claim 6, wherein the pre-transmit traffic stream processing module comprises: An inserting unit, configured to determine A plurality of target frames corresponding to the target DTMB-A single frequency network system and meeting A preset TS packet requirement, and insert one MIP packet into A corresponding MPEG-2 transport stream every other target frame, where the one target frame includes N TS packets, and adjust A value of N according to A transmission rate of A TS code stream, where N is an integer; The zero padding unit is used for determining the working mode of the target DTMB-A single-frequency network system and the OFDM frame corresponding to each target frame in the target frames according to the target frames, and performing zero padding operation on the tail part of the service datA pre-sent in each OFDM frame according to the working mode in A DTMB-A single-frequency network adapter of the target DTMB-A single-frequency network system so as to obtain A zero padding MPEG-2 transmission stream; The control unit is used for acquiring the length information of each OFDM frame in the zero padding MPEG-2 transmission stream, controlling the number of OFDM frames between adjacent MIP packets in the target DTMB-A single-frequency network system to be an integer and the interval between the MIP packets to be less than 1 second according to the length information and the working mode, and controlling the TS code stream to be output in different speed grades according to different modulation modes of the target DTMB-A single-frequency network system through the preset buffer unit.
  8. 8. An electronic device comprising A memory, A processor and A computer program stored on the memory and executable on the processor, the processor executing the program to implement the method of analysis of A DTMB-A single frequency network system according to any one of claims 1-5.
  9. 9. A computer readable storage medium having stored thereon A computer program, the program being executable by A processor for implementing the method of analysis of A DTMB-A single frequency network system according to any one of claims 1-5.
  10. 10. A computer program product comprising A computer program, characterized in that the computer program is executed for implementing the analysis method of A DTMB-A single frequency network system according to any of claims 1-5.

Description

Analysis method and device of DTMB-A single frequency network system Technical Field The application relates to the technical field of digital information transmission, in particular to an analysis method and an analysis device of A DTMB-A single-frequency network system. Background In the conventional analog television broadcasting, in order to avoid co-channel interference, adjacent transmitting base stations transmit signals at different frequencies, and the same frequency can be multiplexed only at a certain distance, and the networking mode of the multi-frequency network (Multiple Frequency Network, MFN) causes serious waste of limited frequency resources. With the transition of terrestrial television broadcasting from an analog age to a digital age, digital television channels are rapidly increased, frequency resources are increasingly tensioned, and a single frequency network (Single Frequency Network, SFN) networking gradually replaces a multi-frequency network by virtue of the advantages of large coverage, low transmitter cost, high frequency utilization rate and the like, so that the terrestrial television broadcasting system becomes a main stream technical scheme of a wireless digital broadcasting coverage network. In a single frequency network, multiple transmitting base stations transmit the same signal at the same time and the same frequency, thereby greatly saving frequency resources and providing diversity gain to enhance the reliability of reception. After the broadcast television is digitalized, the transmitted programs are clearer, the content is richer, and the processing and the storage are more convenient. Compared with satellite digital televisions and cable digital televisions, the ground transmission mode has strong anti-interference capability, can be received under general indoor conditions, has higher flexibility, can support television broadcasting, mobile receiving and portable receiving compatible with standard definition and high definition, has low construction and maintenance costs and the like, and the wireless ground digital television shows a brand-new industrial operation mode, and the existing DTMB has the following two problems: 1. The frame structure of the DTMB system is characterized in that the output of the SFN adapter is A legal MPEG-2 transport stream, the output TS packets form A group according to A certain number N, which is called A large frame (MEGAFRAME), wherein N is necessarily an integer, namely the number of TS packets carried by the DTMB baseband OFDM frame is also necessarily an integer, and then the OFDM block and the control information of the DTMB-A system are not specially processed, so that the number of the TS packets included in the OFDM frame datA is not an integer any more, and therefore the single-frequency network adapter and the synchronous system of the current DTMB system cannot be used in the DTMB-A system. 2. In the current single-frequency network adapter, for A DTMB system with the payload rate of 5.414Mbps to 32.284 Mbps, in order to reduce the clock processing of the SFN adapter, the implementation of the SFN single-frequency network can enable the output of TS code streams to be output according to the clock of 7.56MHz, while for A DTMB-A system with the payload rate of 5.0Mbps to 49.31Mbps, the single-frequency network adapter adopting the fixed clock frequency to output the TS code streams cannot guarantee that the DTMB-A modulator requires that the MIP packet is the first TS packet of OFDM frame datA due to the processing waiting time difference of the DTMB-A modulator. In summary, the current single frequency network adapter cannot meet the requirement of the single frequency network of the DTMB-A system, and needs to be solved. Disclosure of Invention The application provides an analysis method and device of A DTMB-A single-frequency network system, which are used for solving the problems that the current single-frequency network adapter cannot meet the requirement of the single-frequency network of the DTMB-A system. An embodiment of the first aspect of the present application provides an analysis method of A DTMB-A single frequency network system, including the steps of generating an MIP packet according to A pre-transmission mode and GPS information of A target DTMB-A single frequency network system, inserting the MIP packet into pre-transmitted service datA, simultaneously calculating the number and zero padding of service datA packets included in each OFDM frame according to the pre-transmission mode to obtain A service datA stream meeting A preset matching requirement with A DTMB-A transmission net code rate, receiving the service datA stream and control information by each preset transmitting station, taking each MIP packet in the service datA stream as A first datA packet of an OFDM frame in the target DTMB-A single frequency network system, extracting A time tag and A channel maximum delay in the MIP packet, calcul