Analysis method and device for dtmb-a single frequency network system

Abstract

The application relates to an analysis method and device of a DTMB-A single frequency network system, wherein the method comprises the following steps: generating MIP packages according to a pre-transmission mode of the DTMB-A and GPS information, and inserting the MIP packages into pre-transmitted service data; meanwhile, the number of service data packages contained in each OFDM frame and the number of zero supplements are calculated according to the pre-transmission mode, so that a service data stream completely matched with a DTMB-A transmission net code rate is obtained; the service data stream and control information are received by each transmission station, each MIP package in the service data stream is taken as the first data package of an OFDM frame, and the time label and the maximum channel delay in the MIP package are extracted to calculate an additional delay; the service data stream and the control information are modulated, a complex frame synchronization channel is generated according to the additional delay, the data frame information and the control frame information are multiplexed, the radio frequency signal corresponding to the multiplexed signal is generated, and the radio frequency signal is broadcasted and simultaneously transmitted. Therefore, the current single frequency network adapter cannot meet the demand of the DTMB-A system single frequency network and other problems are solved.

Description

Technical Field

[0001] This application relates to the field of digital information transmission technology, and in particular to an analysis method and apparatus for a DTMB-A single-frequency network system. Background Technology

[0002] In traditional analog television broadcasting, to avoid co-channel interference, adjacent base stations transmit signals at different frequencies. The same frequency can only be reused when they are a certain distance apart. This multi-frequency network (MFN) networking method results in a serious waste of limited frequency resources.

[0003] As terrestrial television broadcasting transitions from the analog to the digital era, the number of digital television channels has increased rapidly, leading to increasingly scarce frequency resources. Single Frequency Network (SFN) networking, with its advantages of wide coverage, low transmitter cost, and high frequency utilization, has gradually replaced multi-frequency networks, becoming the mainstream technical solution for wireless digital broadcasting coverage networks. In a SFN, multiple base stations transmit the same signal at the same frequency at the same time, significantly saving frequency resources and providing diversity gain to enhance reception reliability. After the digitization of broadcast television, programs are clearer, content is richer, and processing and storage are more convenient. Compared with satellite digital television and cable digital television, terrestrial transmission has stronger anti-interference capabilities, can be received under normal indoor conditions, and has high flexibility, supporting standard definition and high definition compatible television broadcasting, mobile reception, and portable reception. It also has low construction and maintenance costs. Wireless terrestrial digital television will present a completely new industry operation model. However, existing DTMB systems face the following two problems:

[0004] 1. The characteristics of the DTMB system frame structure: the output of its SFN adapter is a valid MPEG-2 transport stream. The output TS packets are grouped into a group according to a certain number N, called a Megaframe, where N must be an integer. That is, after the DTMB baseband OFDM is framed, the number of TS packets it carries must also be an integer. Afterwards, the OFDM block and control information processing of the DTMB-A system is not specially processed, so the number of TS packets in its OFDM frame data is no longer an integer. Therefore, the current DTMB system's single-frequency network adapter and synchronization system cannot be used in the DTMB-A system.

[0005] 2. For current single-frequency network adapters, in order to reduce the clock processing of SFN adapters, the implementation of SFN single-frequency network can output the TS code stream at a clock of 7.56MHz for DTMB systems with a net payload rate of 5.0Mbps to 49.31Mbps. However, for DTMB-A systems with a net payload rate of 5.0Mbps to 49.31Mbps, due to the processing wait time difference of the DTMB-A modulator, single-frequency network adapters that use a fixed clock frequency to output the TS code stream cannot guarantee the requirement of the DTMB-A modulator that the MIP packet must be the first TS packet of the OFDM frame data.

[0006] In summary, the current single-frequency network adapter cannot meet the single-frequency network requirements of the DTMB-A system, and this issue urgently needs to be addressed. Summary of the Invention

[0007] This application provides an analysis method and apparatus for a DTMB-A single-frequency network system to solve the problem that current single-frequency network adapters cannot meet the single-frequency network requirements of DTMB-A systems.

[0008] The first aspect of this application provides an analysis method for a DTMB-A single-frequency network system, comprising the following steps: generating MIP packets based on the pre-transmission mode and GPS information of the target DTMB-A single-frequency network system, inserting the MIP packets into the pre-transmitted service data, and simultaneously calculating the number of service data packets and the amount of zero padding in each OFDM frame according to the pre-transmission mode to obtain a service data stream that meets a preset matching requirement with the DTMB-A transmission net code rate; receiving the service data stream and control information through preset transmitting stations, and using each MIP packet in the service data stream as the first data packet of the OFDM frame in the target DTMB-A single-frequency network system, and extracting the time stamp and maximum channel delay from the MIP packets to determine the time... The tag and the maximum channel delay are used to calculate the additional delay; the service data stream and the control information are preprocessed, and the preprocessed service data stream and control information are scrambled, encoded, constellation mapped and symbol interleaved to obtain the corresponding data processing results; the data processing results and the preset PN-MC sequence are OFDM modulated and frequency grouped to generate the data frame information corresponding to the service data stream and the control frame information corresponding to the control information; through the additional delay, a multiframe synchronization channel is generated, and the data frame information and the control frame information are multiplexed and synthesized into multiframes using the multiframe synchronization channel to obtain the corresponding multiplexed signal; the multiplexed signal is converted into a radio frequency signal in the radio frequency band for simultaneous broadcast transmission.

[0009] Optionally, in one embodiment of this application, the step of generating MIP packets based on the pre-transmission mode and GPS information of the target DTMB-A single-frequency network system, inserting the MIP packets into the pre-transmitted service data, and simultaneously calculating the number of service data packets and the amount of zero padding in each OFDM frame according to the pre-transmission mode to obtain a service data stream that meets the preset matching requirements with the DTMB-A transmission net bit rate includes: determining multiple target frames corresponding to the target DTMB-A single-frequency network system that meet the preset TS packet requirements, and inserting a MIP packet into the corresponding MPEG-2 transport stream for every other target frame, wherein each target frame contains N TS packets, and the value of N is adjusted according to the transmission rate of the TS bit stream, and N is an integer; determining the target DTMB-A single-frequency network system based on the multiple target frames. The operating mode of the DTMB-A single-frequency network system and the OFDM frame corresponding to each of the multiple target frames are determined. Zero-padding is performed on the tail of the pre-transmitted service data in each OFDM frame in the DTMB-A single-frequency network adapter of the target DTMB-A single-frequency network system according to the operating mode, to obtain a zero-padding MPEG-2 transport stream. The length information of each OFDM frame in the zero-padding MPEG-2 transport stream is obtained, and the number of OFDM frames between adjacent MIP packets in the target DTMB-A single-frequency network system is controlled to be an integer and the interval between MIP packets is less than 1 second according to the length information and the operating mode. Furthermore, the TS code stream is controlled to output at different rate levels according to different modulation modes of the target DTMB-A single-frequency network system through a preset buffer unit.

[0010] Optionally, in one embodiment of this application, the step of receiving the service data stream through preset transmitting stations, and using each MIP packet in the service data stream as the first data packet of the OFDM frame in the target DTMB-A single-frequency network system, and extracting the time stamp and maximum channel delay from the MIP packet to calculate the additional delay based on the time stamp and the maximum channel delay, includes: controlling a preset DTMB-A exciter to use each MIP packet in the service data stream as the first data packet of the OFDM frame in the target DTMB-A single-frequency network system, and detecting the service data stream; when a MIP packet is detected in the service data stream, obtaining the start time of the OFDM frame corresponding to the MIP packet and the time difference of the PPS signal generated by a preset GPS receiver, and extracting the time stamp and maximum channel delay from the MIP packet; and calculating the additional delay corresponding to the service data stream based on the start time, the time difference, the time stamp, the maximum channel delay, and a preset additional delay calculation strategy.

[0011] Optionally, in one embodiment of this application, the step of generating a multiframe synchronization channel through the additional delay, and using the multiframe synchronization channel to multiplex the data frame information and the control frame information to synthesize a multiframe to obtain a corresponding multiplexed signal, and converting the multiplexed signal into a radio frequency signal in the radio frequency band for simultaneous broadcast transmission of the radio frequency signal, includes: aligning the data frame information and the control frame information passing through different network paths according to the additional delay to synchronize the signal transmission time in the target DTMB-A single-frequency network system, and generating the multiframe synchronization channel; using the multiframe synchronization channel to multiplex the data frame information and the control frame information to synthesize a multiframe to obtain the multiplexed signal, and performing baseband post-processing on the multiplexed signal to generate a baseband transmission signal; performing orthogonal up-conversion on the baseband transmission signal to convert the multiplexed signal into a radio frequency signal in the radio frequency band, and simultaneously broadcasting the radio frequency signal.

[0012] Optionally, in one embodiment of this application, the mathematical expression of the additional delay calculation strategy is:

[0013] STS+MD=Measured Delay+Additional Delay

[0014] Wherein, STS represents the time tag; MD represents the maximum channel delay; Measured Delay represents the time difference; and Additional Delay represents the additional delay.

[0015] A second aspect of this application provides an analysis apparatus for a DTMB-A single-frequency network system, comprising: a pre-transmission service stream processing module, configured to generate MIP packets based on the pre-transmission mode and GPS information of the target DTMB-A single-frequency network system, insert the MIP packets into the pre-transmission service data, and calculate the number of service data packets and the amount of zero padding in each OFDM frame according to the pre-transmission mode, so as to obtain a service data stream that meets a preset matching requirement with the DTMB-A transmission net code rate; and a receiving module, configured to receive the service data stream and control information through preset transmitting stations, and use each MIP packet in the service data stream as the first data packet of the OFDM frame in the target DTMB-A single-frequency network system, and extract the time tag and maximum channel delay from the MIP packet, so as to obtain a service data stream that meets a preset matching requirement with the DTMB-A transmission net code rate; The time stamp and the maximum channel delay are used to calculate the additional delay; the modulation module is used to preprocess the service data stream and the control information, and to perform scrambling, encoding, constellation mapping and symbol interleaving on the preprocessed service data stream and control information to obtain the corresponding data processing results, and to perform OFDM modulation and frequency grouping on the data processing results and the preset PN-MC sequence to generate data frame information corresponding to the service data stream and control frame information corresponding to the control information; the transmission module is used to generate a multiframe synchronization channel through the additional delay, and to use the multiframe synchronization channel to multiplex the data frame information and the control frame information to synthesize a multiframe to obtain the corresponding multiplexed signal, and to convert the multiplexed signal into a radio frequency signal in the radio frequency band for simultaneous broadcast transmission of the radio frequency signal.

[0016] Optionally, in one embodiment of this application, the pre-transmission service stream processing module includes: an insertion unit, configured to determine multiple target frames corresponding to the target DTMB-A single-frequency network system that meet preset TS packet requirements, and insert a MIP packet into the corresponding MPEG-2 transport stream for every target frame, wherein each target frame contains N TS packets, and the value of N is adjusted according to the transmission rate of the TS stream, and N is an integer; and a zero-padding unit, configured to determine the operating mode of the target DTMB-A single-frequency network system and the OFDM frame corresponding to each target frame in the multiple target frames, and insert a MIP packet into the corresponding MPEG-2 transport stream for every target frame. In the DTMB-A single-frequency network adapter of the network system, zero-padding is performed on the end of the service data pre-transmitted in each OFDM frame according to the working mode to obtain a zero-padding MPEG-2 transport stream; the control unit is used to obtain the length information of each OFDM frame in the zero-padding MPEG-2 transport stream, and according to the length information and the working mode, control 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 MIP packets to be less than 1 second, and control the TS code stream to be output at different rate levels according to different modulation modes of the target DTMB-A single-frequency network system through a preset buffer unit.

[0017] Optionally, in one embodiment of this application, the receiving module includes: a determining unit, configured to control a preset DTMB-A exciter to use each MIP packet in the service data stream as the first data packet of the OFDM frame in the target DTMB-A single-frequency network system, and to detect the service data stream; a detecting unit, configured to, when a MIP packet is detected in the service data stream, obtain the start time of the OFDM frame corresponding to the MIP packet and the time difference of the PPS signal generated by a preset GPS receiver, and extract the time stamp and the maximum channel delay from the MIP packet; and a calculating unit, configured to calculate the additional delay corresponding to the service data stream based on the start time, the time difference, the time stamp, the maximum channel delay, and a preset additional delay calculation strategy.

[0018] Optionally, in one embodiment of this application, the transmission module includes: a synchronization unit, configured to align the data frame information and the control frame information passing through different network paths according to the additional delay, so as to synchronize the signal transmission time in the target DTMB-A single-frequency network system and generate the multiframe synchronization channel; a multiplexing unit, configured to use the multiframe synchronization channel to multiplex the data frame information and the control frame information to synthesize a multiframe, so as to obtain the multiplexed signal, and to perform baseband post-processing on the multiplexed signal to generate a baseband transmission signal; and a frequency conversion unit, configured to perform orthogonal up-conversion operation on the baseband transmission signal to convert the multiplexed signal into a radio frequency signal in the radio frequency band, and to broadcast the radio frequency signal simultaneously.

[0019] Optionally, in one embodiment of this application, the mathematical expression of the additional delay calculation strategy is:

[0020] STS+MD=Measured Delay+Additional Delay

[0021] Wherein, STS represents the time tag; MD represents the maximum channel delay; Measured Delay represents the time difference; and Additional Delay represents the additional delay.

[0022] A third aspect of this application provides an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the analysis method for a DTMB-A single-frequency network system as described in the above embodiments.

[0023] A fourth aspect of this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described analysis method for a DTMB-A single-frequency network system.

[0024] A fifth aspect of this application provides a computer program product, including a computer program that is executed to implement the analysis method for the DTMB-A single-frequency network system described above.

[0025] Therefore, the embodiments of this application have the following beneficial effects:

[0026] The embodiments of this application can generate MIP packets based on the pre-transmission mode and GPS information of the target DTMB-A single-frequency network system, insert MIP packets into the pre-transmitted service data, and calculate the number of service data packets and the amount of zero padding in each OFDM frame according to the pre-transmission mode to obtain a service data stream that meets the preset matching requirements of the DTMB-A transmission net code rate; receive the service data stream and control information through preset transmission stations, and use each MIP packet in the service data stream as the first data packet of the OFDM frame in the target DTMB-A single-frequency network system, and extract the time tag and maximum channel delay from the MIP packet to calculate the additional delay based on the time tag and maximum channel delay; preprocess the service data stream and control information, and then process the preprocessed data. The system performs scrambling, encoding, constellation mapping, and symbol interleaving on the service data stream and control information to obtain the corresponding data processing results. The data processing results and a preset PN-MC sequence are then subjected to OFDM modulation and frequency grouping to generate data frame information corresponding to the service data stream and control frame information corresponding to the control information. By adding a delay, a multiframe synchronization channel is generated, and the data frame information and control frame information are multiplexed and synthesized into multiframes using this channel to obtain the corresponding multiplexed signal. This multiplexed signal is then converted into a radio frequency signal for simultaneous broadcast transmission. This avoids synchronization system calculation delay errors caused by the waiting time of the DTMB-A modulator in processing the TS code stream, meeting the requirements of a single-frequency network in the DTMB-A system. Therefore, it solves the problem that current single-frequency network adapters cannot meet the requirements of a single-frequency network in the DTMB-A system.

[0027] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0028] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0029] Figure 1 This is a flowchart illustrating an analysis method for a DTMB-A single-frequency network system according to an embodiment of this application.

[0030] Figure 2 A schematic diagram of a synchronization system for measuring delay is provided as an embodiment of this application;

[0031] Figure 3 A schematic diagram of the control structure of an analysis system for a target DTMB-A single-frequency network system is provided as an embodiment of this application;

[0032] Figure 4A schematic diagram of zero padding for MIP packets is provided as an embodiment of this application;

[0033] Figure 5 A schematic diagram of a time stamp provided for one embodiment of this application;

[0034] Figure 6 A schematic diagram of the DTMB-A system origination principle provided in one embodiment of this application;

[0035] Figure 7 This is an example diagram of an analysis device for a DTMB-A single-frequency network system according to an embodiment of this application;

[0036] Figure 8 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application.

[0037] Among them, the analysis device of the 10-DTMB-A single-frequency network system; 100-pre-transmission service code stream processing module, 200-receiving module, 300-modulation module, 400-transmitting module; 801-memory, 802-processor, 803-communication interface. Detailed Implementation

[0038] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0039] The following describes an analysis method and apparatus for a DTMB-A single-frequency network system according to embodiments of this application, with reference to the accompanying drawings. Addressing the problems mentioned in the background art, this application provides an analysis method for a DTMB-A single-frequency network system. In this method, MIP packets are generated based on the pre-transmission mode and GPS information of the target DTMB-A single-frequency network system, and MIP packets are inserted into the pre-transmitted service data. Simultaneously, the number of service data packets and the amount of zero padding in each OFDM frame are calculated based on the pre-transmission mode to obtain a service data stream that meets a preset matching requirement with the DTMB-A transmission net code rate. The service data stream and control information are received through preset transmitting stations, and each MIP packet in the service data stream is used as the first data packet of the OFDM frame in the target DTMB-A single-frequency network system. The time stamp and maximum channel delay in the MIP packets are extracted to calculate the additional delay based on the time stamp and maximum channel delay. The service data stream is then analyzed. The system preprocesses the data stream and control information, then performs scrambling, encoding, constellation mapping, and symbol interleaving on the preprocessed data stream and control information to obtain the corresponding data processing results. The data processing results and a preset PN-MC sequence are then subjected to OFDM modulation and frequency grouping to generate data frame information corresponding to the service data stream and control frame information corresponding to the control information. By adding a delay, a multiframe synchronization channel is generated, and the data frame information and control frame information are multiplexed and synthesized into multiframes using this channel to obtain the corresponding multiplexed signal. This multiplexed signal is then converted into a radio frequency signal for simultaneous broadcast transmission. This avoids synchronization system calculation delay errors caused by the waiting time of the DTMB-A modulator in processing the TS code stream, meeting the requirements of a single-frequency network in the DTMB-A system. Therefore, it solves the problem that current single-frequency network adapters cannot meet the requirements of a single-frequency network in the DTMB-A system.

[0040] Specifically, Figure 1 This is a flowchart illustrating an analysis method for a DTMB-A single-frequency network system provided in an embodiment of this application.

[0041] like Figure 1 As shown, the analysis method for this DTMB-A single-frequency network system includes the following steps:

[0042] In step S101, MIP packets are generated based on the pre-transmission mode and GPS information of the target DTMB-A single-frequency network system, and MIP packets are inserted into the pre-transmitted service data. At the same time, the number of service data packets and the number of zero padding in each OFDM frame are calculated based on the pre-transmission mode to obtain a service data stream that meets the preset matching requirements with the DTMB-A transmission net code rate.

[0043] In step S102, service data streams and control information are received through preset transmitters, and each MIP packet in the service data stream is used as the first data packet of the OFDM frame in the target DTMB-A single-frequency network system. The time stamp and maximum channel delay in the MIP packet are extracted to calculate the additional delay based on the time stamp and maximum channel delay.

[0044] The embodiments of this application first generate MIP packets based on the pre-transmission mode and GPS information of the target DTMB-A single-frequency network system, insert these MIP packets into the pre-transmitted service data, and calculate the number of service data packets and the number of zero padding in each OFDM frame based on the DTMB-A pre-transmission mode, finally obtaining a set of service data streams that perfectly match the DTMB-A transmission net code rate.

[0045] Secondly, embodiments of this application can receive service data streams and control information through various transmitting stations, and use each MIP packet in the service data stream as the first data packet of the OFDM frame in the target DTMB-A single-frequency network system, and extract the time stamp and maximum channel delay from the MIP packet to calculate the additional delay based on the time stamp and maximum channel delay, such as... Figure 2 As shown.

[0046] Optionally, in one embodiment of this application, MIP packets are generated based on the pre-transmission mode and GPS information of the target DTMB-A single-frequency network system, and MIP packets are inserted into the pre-transmitted service data. Simultaneously, the number of service data packets and the amount of zero-padding in each OFDM frame are calculated based on the pre-transmission mode to obtain a service data stream that meets a preset matching requirement with the DTMB-A transmission net bit rate. This includes: determining multiple target frames corresponding to the target DTMB-A single-frequency network system that meet preset TS packet requirements, and inserting a MIP packet into the corresponding MPEG-2 transport stream for every other target frame. Each target frame contains N TS packets, and the value of N is adjusted according to the transmission rate of the TS bit stream, where N is an integer. The process involves determining the target... The system operates in a DTMB-A single-frequency network and identifies the OFDM frames corresponding to each target frame in multiple target frames. In the DTMB-A single-frequency network adapter of the target DTMB-A single-frequency network system, zero-padding is performed on the tail of the pre-transmitted service data in each OFDM frame according to the operating mode to obtain a zero-padding MPEG-2 transport stream. The system acquires the length information of each OFDM frame in the zero-padding MPEG-2 transport stream and, based on the length information and operating mode, controls 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 MIP packets to be less than 1 second. Furthermore, through a preset buffer unit, the system controls the TS stream to output at different rate levels according to different modulation modes of the target DTMB-A single-frequency network system.

[0047] It should be noted that the embodiments of this application utilize, as Figure 3 The analysis system of the target DTMB-A single-frequency network system shown above processes the TS code stream to obtain and output the target DTMB-A single-frequency network system. Figure 4 The specific steps for the shown bitstream sequence are as follows:

[0048] S1. A MIP packet is inserted into the MPEG-2 transport stream every other large frame. The MIP packet carries the synchronization time tag related to the GPS receiver and the maximum system delay information to each relay station. Among them, a large frame contains N TS packets, where N is an integer and the value of N can be adjusted according to the transmission rate of the TS bitstream.

[0049] S2. A forward error control method combining LDPC and BCH is used, where BCH code is used to provide error protection for the scrambled bit stream, and the bit stream after scrambling and BCH encoding is FEC encoded.

[0050] As one possible approach, embodiments of this application may employ LDPC codes, with the code including two different code lengths of 61440 and 15360 and three different code rates of 1 / 2, 2 / 3, and 5 / 6; furthermore, the target DTMB-A single-frequency network system may employ quasi-cyclic LDPC codes.

[0051] S3. In embodiments of this application, a large frame can be used as an OFDM frame in a target DTMB-A single-frequency network system, with time stamps such as... Figure 5 As shown; furthermore, in the DTMB-A single-frequency network adapter, the embodiments of this application can, according to the specific operating mode of the target DTMB-A single-frequency network system, perform zero-padding operation at the end of the service data for each OFDM frame of the target DTMB-A single-frequency network system, such as... Figure 4 As shown; in order to ensure that the service data transmitted by the DTMB-A exciters of each relay station is completely consistent, the DTMB-A exciter cannot insert data for the service data required for each OFDM frame of the target DTMB-A single-frequency network system.

[0052] S4. Between adjacent MIP packets, embodiments of this application can control the number of OFDM frames in the target DTMB-A single-frequency network system to be an integer, and the interval between MIP packets to be less than 1 second, based on the specific working mode of DTMB-A and the length of the OFDM frame, so as to generate data frame information and control frame information.

[0053] In summary, the embodiments of this application, in the DTMB-A single-frequency network adapter, according to the specific working mode of the target DTMB-A single-frequency network system, perform corresponding zero-padding operations at the end of the service data of each OFDM frame of the target DTMB-A single-frequency network system; at the same time, the DTMB-A single-frequency network adapter control ensures that adjacent MIP packets contain an integer number of DTMB-A OFDM frames.

[0054] Those skilled in the art should understand that, due to the large net payload rate extension of DTMB-A, adding a data buffer unit at the final output of the SFN single-frequency network can enable the TS code stream to be output at different rate levels according to different modulation modes of DTMB-A, so as to avoid the synchronization system calculation delay error caused by the waiting time of the DTMB-A modulator in processing the TS code stream.

[0055] Furthermore, it is understood that the embodiments of this application no longer add a MIP packet every fixed 500 milliseconds, but according to the specific working mode of DTMB-A and the length of the OFDM frame, so as not only can it be guaranteed that there is an integer OFDM frame between two adjacent MIP packets, but also that the interval between MIP packets is less than 1 second.

[0056] In step S103, the service data stream and control information are preprocessed, and the preprocessed service data stream and control information are scrambled, encoded, constellation mapped and symbol interleaved to obtain the corresponding data processing results. The data processing results and the preset PN-MC sequence are then OFDM modulated and frequency grouped to generate the data frame information corresponding to the service data stream and the control frame information corresponding to the control information.

[0057] In step S104, a multiframe synchronization channel is generated by adding a delay, and the data frame information and control frame information are multiplexed and synthesized into a multiframe using the multiframe synchronization channel to obtain the corresponding multiplexed signal. The multiplexed signal is then converted into a radio frequency signal in the radio frequency band for simultaneous broadcasting.

[0058] Furthermore, embodiments of this application also require the use of multiple collectors to collect service data from the service data stream in the DTMB-A single-frequency network system, and to collect control information. The collected service data and control information are preprocessed to obtain standard service data corresponding to each service data and standard control information corresponding to the control information. In addition, embodiments of this application can use the collected service data and control data to construct a data channel and a control channel.

[0059] Data frames in the data channel use independent coding and modulation, and their coding and modulation modes can be flexibly configured according to actual needs. Each standard service data stream undergoes forward error correction coding, constellation mapping, and symbol interleaving, and then forms a data frame through IDFT transformation and the addition of a frame header. Control frames in the control channel employ low-rate forward error correction coding, QPSK constellation mapping, and symbol interleaving, and are formed through IDFT transformation and the addition of a frame header, such as... Figure 6 As shown.

[0060] In actual execution, control frames and data frames can use the same or different frame header lengths and frame body lengths. The frame header consists of a frequency domain binary pseudo-random sequence (i.e., a PN-MC sequence).

[0061] In addition, the DTMB-A single-frequency network system includes constellation mappings such as QPSK, 16APK, 64APSK, and 256APSK. Among them, the control frame body, multiframe synchronization signal, and frame header signal can be modulated using QPSK, while the data frame body can be modulated using QPSK, 16APSK, 64APSK, or 256APSK. Each service signal can use a fixed channel coding and constellation mapping method.

[0062] Therefore, the embodiments of this application can perform scrambling, encoding, constellation mapping and symbol interleaving on multiple preprocessed service data and control information, and after generating the PN-MC sequence, perform OFDM modulation and frequency grouping on the processed service data and PN-MC sequence, thereby providing reliable data support for subsequent data multiplexing and other operations.

[0063] Furthermore, embodiments of this application can generate a multiframe synchronization channel, and use the multiframe synchronization channel to multiplex service data that has undergone OFDM modulation and frequency grouping to synthesize multiframes, and convert the multiplexed signal into radio frequency signals in the radio frequency band in preparation for simultaneous broadcast transmission.

[0064] Optionally, in one embodiment of this application, service data streams are received through preset transmitting stations, and each MIP packet in the service data stream is used as the first data packet of the OFDM frame in the target DTMB-A single-frequency network system. The time stamp and maximum channel delay in the MIP packet are extracted to calculate the additional delay based on the time stamp and maximum channel delay. This includes: controlling a preset DTMB-A exciter to use each MIP packet in the service data stream as the first data packet of the OFDM frame in the target DTMB-A single-frequency network system, and detecting the service data stream; when a MIP packet in the service data stream is detected, obtaining the start time of the OFDM frame corresponding to the MIP packet and the time difference of the PPS signal generated by a preset GPS receiver, and extracting the time stamp and maximum channel delay in the MIP packet; and calculating the additional delay corresponding to the service data stream based on the start time, time difference, time stamp, maximum channel delay, and a preset additional delay calculation strategy.

[0065] It should be noted that, at the beginning of operation, the embodiments of this application can check the MIP packet and control the DTMB-A exciter to use the MIP packet as the first data packet of the OFDM frame of the DTMB-A single-frequency network system; thereafter, at each receiving point, when the MIP is detected, the embodiments of this application can measure the time difference between the start time of the corresponding local large frame and the time difference between the PPS signal obtained from the GPS receiver and the Measured Delay. At the same time, the STS time stamp and the maximum delay (MD) information of the channel are extracted from the MIP, and then the additional delay that should be added to the transmission code stream is calculated.

[0066] Optionally, in one embodiment of this application, the mathematical expression for the additional delay calculation strategy is:

[0067] STS+MD=Measured Delay+Additional Delay

[0068] Wherein, STS represents time tag; MD represents maximum channel delay; Measured Delay represents time difference; and Additional Delay represents additional delay.

[0069] It should be noted that, in the embodiments of this application, the additional delay to be added to the transmitted bitstream can be calculated using the following formula:

[0070] STS+MD=Measured Delay+Additional Delay

[0071] Wherein, STS represents time tag; MD represents maximum channel delay; Measured Delay represents time difference; and Additional Delay represents additional delay.

[0072] Optionally, in one embodiment of this application, a multiframe synchronization channel is generated by adding a delay, and the data frame information and control frame information are multiplexed and synthesized into a multiframe using the multiframe synchronization channel to obtain a corresponding multiplexed signal. The multiplexed signal is then converted into a radio frequency signal in the radio frequency band for simultaneous broadcast transmission. This includes: aligning data frame information and control frame information passing through different network paths according to the added delay to synchronize the signal transmission time in the target DTMB-A single-frequency network system and generating a multiframe synchronization channel; multiplexing and synthesizing data frame information and control frame information using the multiframe synchronization channel to obtain a multiplexed signal; performing baseband post-processing on the multiplexed signal to generate a baseband transmission signal; performing orthogonal up-conversion on the baseband transmission signal to convert the multiplexed signal into a radio frequency signal in the radio frequency band; and broadcasting the radio frequency signal simultaneously.

[0073] It should be noted that the specific steps for preparing to broadcast and transmit simultaneously in this embodiment are as follows:

[0074] S1. Based on the calculated additional delay, align the transmission code streams propagating through different network paths to synchronize the signal transmission time in the DTMB-A single-frequency network system, such as... Figure 2 As shown; and using the calculated additional delay and delay signal to generate a multiframe synchronization channel;

[0075] S2. The service data that are OFDM modulated and frequency grouped are multiplexed and synthesized into multiframes using the multiframe synchronization channel (i.e., the control frame and the data frame formed by each service are multiplexed and synthesized into one multiframe signal). The multiplexed signal (i.e. the multiframe signal) is then processed by baseband post-processing to obtain the baseband transmission signal. This baseband signal is then orthogonally up-converted to form a radio frequency signal in the radio band, in preparation for simultaneous broadcast transmission.

[0076] The execution logic of the analysis method for the DTMB-A single-frequency network system of this application will be described below through a specific embodiment.

[0077] In practical applications, the DTMB-A single-frequency network adapter and its synchronization system have been successfully implemented using FPGA. The specific embodiments of this application are illustrated by taking the guard interval K=256, LDPC coding rate 2 / 3, OFDM frame block length N=32768 and constellation mapping using 256APSK as examples.

[0078] According to the operating mode of the DTMB-A single-frequency network system, the control unit in this specific embodiment will control an OFDM frame to contain P=27 TS packets, followed by zero-padding to add Q=11 bytes of "0" data. The above data constitutes a complete DTMB-AOFDM frame data. The specific calculation of P and Q values ​​should refer to the detailed parameters in the DTMB-A standard.

[0079] The control unit in this specific embodiment controls the MIP packet as the first data packet of an OFDM frame in a DTMB-A single-frequency network system. After adding P-1 TS service data packets, it performs data replenishment processing of the OFDM frame in the DTMB-A single-frequency network system, that is, it supplements Q bytes of "0" data.

[0080] Depending on a specific operating mode of DTMB-A, such as the DTMB-A single-frequency network system operating mode using an OFDM frame block size of 32768, the data length of each OFDM frame is 227.163 milliseconds. According to the MIP insertion method of this application embodiment, the time interval of MIP packets can be 454.326 milliseconds or 681.49 milliseconds, that is, the time interval between every two adjacent MIP packets can be 2 or 3 DTMB-A OFDM frames.

[0081] In a specific embodiment of this application, the symbol rate of the DTMB-A single-frequency network system in Normal mode is 7.56MHz. Under different signal frame lengths, different LDPC code rates, and modulation schemes, the payload data rate of the DTMB-A single-frequency network system ranges from 5.0Mbps to 49.31Mbps. The payload data rates of the system in various modes are shown in Table 1.

[0082] Table 1

[0083]

[0084] For constellation diagrams using 256APSK, if the payload rate is below 30.24Mbps, the TS stream is output at a rate of 3.78MB / Hz; for application modes with payload rates below 30.24Mbps and 45.36Mbps, the TS stream is output at a rate of 5.67MB / Hz; and for application modes with payload rates exceeding 45.36Mbps, the TS stream is output at a rate of 7.56MB / Hz.

[0085] In a specific embodiment of this application, a 256APSK constellation diagram can be used, with each symbol containing 8 bits of data information. The system's net payload data rate is 39.41 Mbps, and the net payload symbol rate is approximately 39.41 / 8 = 4.93 Mbps. To avoid synchronization system calculation delay errors caused by the waiting time of the DTMB-A modulator in processing the TS code stream, the buffer processing of its single-frequency network adapter outputs the TS code stream at a rate of 5.67 MB / Hz.

[0086] Furthermore, this application can also construct a corresponding analysis system for the DTMB-A single-frequency network system based on the analysis method of the DTMB-A single-frequency network system. The analysis system for the DTMB-A single-frequency network system of this application will be described in detail and introduced below with reference to the accompanying drawings.

[0087] The analysis system of the DTMB-A single-frequency network system in this application mainly includes a single-frequency network adapter, a DTMB-A modulator, and a global positioning system receiver.

[0088] Among them, the single-frequency network adapter is used to adapt information frames in the DTMB-A single-frequency network system;

[0089] The DTMB-A modulator is used to analyze the Synchronization Time Tag (STS) and Maximum Delay (MD) in a DTMB-A single-frequency network system and calculate the additional delay.

[0090] A GPS receiver is used to receive signals transmitted by a transmitter and generates a PPS signal every second for time synchronization.

[0091] Specifically, the single-frequency network adapter includes an MPEG-2 generation module, an encoding processing module, a multiplexing module, a control module, and an output module;

[0092] The MPEG-2 generation module inserts a MIP packet into the MPEG-2 transport stream every other large frame. The MIP packet carries a synchronization time tag related to the GPS receiver and the maximum system delay information to each relay station. A large frame contains N TS packets, where N is an integer and the value of N is adjusted according to the transmission rate of the TS stream. At the same time, a large frame can be used as an OFDM frame in the DTMB-A single-frequency network system.

[0093] The encoding processing module is used to select the forward error control method combining LDPC+BCH. The BCH code is used to provide error protection for the scrambled bitstream. The bitstream after scrambling and BCH encoding is FEC encoded using LDPC code, which includes two different code lengths of 61440 and 15360 and three different code rates of 1 / 2, 2 / 3 and 5 / 6. The LDPC code used in the DTMB-A system is a quasi-cyclic LDPC code.

[0094] The multiplexing module is used to multiplex all received signals into a single frame.

[0095] The control module is used to control the signal adaptation in the single-frequency network adapter;

[0096] The output module is used to output the MPEG-2 transport stream with MIP insertion.

[0097] like Figure 3 As shown, the control module includes a zero-filling unit, a MIP insertion control unit, a rounding control unit, and a buffer control unit.

[0098] The zero-padding unit is used in the DTMB-A single-frequency network adapter to perform zero-padding operation at the end of the service data for each OFDM frame of the DTMB-A system, according to the specific working mode of DTMB-A.

[0099] The rounding control unit is used to control the number of OFDM frames in the DTMB-A single-frequency network system to be an integer between adjacent MIP packets, based on the specific operating mode of DTMB-A and the length of the OFDM frame, and the interval between MIP packets is less than 1 second;

[0100] The buffer unit is used to control the TS bitstream to be output at different rate levels.

[0101] The DTMB-A modulator includes a synchronization system module, an additional delay calculation module, and a speed selection module;

[0102] The synchronization system module is used to check the MIP packet at the beginning of operation and control the DTMB-A exciter to use the MIP packet as the first data packet of the OFDM frame of the DTMB-A system.

[0103] The additional delay calculation module is used at each receiving point to measure the start time of the corresponding large frame and the time difference (Measured Delay) between the start time and the PPS signal obtained from the GPS receiver when MIP is detected. Simultaneously, it extracts the STS time stamp and the maximum channel delay (MD) information from the MIP, and calculates the additional delay to be added to the transmitted bitstream using the following formula:

[0104] STS+MD=Measured Delay+Additional Delay

[0105] Wherein, STS represents time tag; MD represents maximum channel delay; Measured Delay represents time difference; and Additional Delay represents additional delay.

[0106] The additional delay is calculated to align the transmission streams that propagate through different network paths, thereby synchronizing the signal transmission time in the DTMB-A single-frequency network system.

[0107] The speed selection module is used to select different TS code stream output speeds according to different modulation modes of DTMB-A, and transmit the selected speed to the buffer unit.

[0108] A GPS receiver includes a receiving module and a PPS signal generation module. The receiving module is used to receive the adapted and modulated signal, while the PPS signal generation module is used to generate and provide a 1PPS signal for time synchronization.

[0109] According to the analysis method for a DTMB-A single-frequency network system proposed in this application, MIP packets are generated based on the pre-transmission mode and GPS information of the target DTMB-A single-frequency network system. These MIP packets are then inserted into the pre-transmitted service data. Simultaneously, the number of service data packets and the amount of zero-padding in each OFDM frame are calculated based on the pre-transmission mode to obtain a service data stream that meets a preset matching requirement with the DTMB-A transmission net code rate. The service data stream and control information are received through preset transmitting stations, and each MIP packet in the service data stream is used as the first data packet of the OFDM frame in the target DTMB-A single-frequency network system. The time stamp and maximum channel delay in the MIP packets are extracted to calculate the additional delay based on the time stamp and maximum channel delay. The service data stream and control information are then processed... The system performs preprocessing, including scrambling, encoding, constellation mapping, and symbol interleaving of the preprocessed service data stream and control information to obtain the corresponding data processing results. The data processing results and a preset PN-MC sequence are then subjected to OFDM modulation and frequency grouping to generate data frame information corresponding to the service data stream and control frame information corresponding to the control information. By adding a delay, a multiframe synchronization channel is generated, and the data frame information and control frame information are multiplexed and synthesized into multiframes using this channel to obtain the corresponding multiplexed signal. This multiplexed signal is then converted into a radio frequency signal for simultaneous broadcast transmission. This avoids synchronization system calculation delay errors caused by the waiting time of the DTMB-A modulator in processing the TS code stream, thus meeting the requirements of a single-frequency network in the DTMB-A system.

[0110] Secondly, the analysis apparatus for a DTMB-A single-frequency network system according to an embodiment of this application will be described with reference to the accompanying drawings.

[0111] Figure 7 This is a block diagram of the analysis device of the DTMB-A single-frequency network system according to an embodiment of this application.

[0112] like Figure 7As shown, the analysis device 10 of the DTMB-A single-frequency network system includes: a pre-transmission service code stream processing module 100, a receiving module 200, a modulation module 300, and a transmitting module 400.

[0113] The pre-transmission service code stream processing module 100 is used to generate MIP packets based on the pre-transmission mode and GPS information of the target DTMB-A single-frequency network system, insert MIP packets into the pre-transmission service data, and calculate the number of service data packets and the number of zero padding in each OFDM frame according to the pre-transmission mode, so as to obtain a service data stream that meets the preset matching requirements with the DTMB-A transmission net code rate.

[0114] The receiving module 200 is used to receive service data streams and control information through preset transmitting stations, and to take each MIP packet in the service data stream as the first data packet of the OFDM frame in the target DTMB-A single-frequency network system, and to extract the time tag and maximum channel delay in the MIP packet to calculate the additional delay based on the time tag and maximum channel delay.

[0115] The modulation module 300 is used to preprocess the service data stream and control information, and to perform scrambling, encoding, constellation mapping and symbol interleaving on the preprocessed service data stream and control information to obtain the corresponding data processing results. The module also performs OFDM modulation and frequency grouping on the data processing results and the preset PN-MC sequence to generate data frame information corresponding to the service data stream and control frame information corresponding to the control information.

[0116] The transmitting module 400 is used to generate a multiframe synchronization channel by adding a delay, and to use the multiframe synchronization channel to multiplex data frame information and control frame information to synthesize a multiframe to obtain a corresponding multiplexed signal. The multiplexed signal is then converted into a radio frequency signal in the radio frequency band for simultaneous broadcasting.

[0117] Optionally, in one embodiment of this application, the pre-transmission service stream processing module 100 includes: an insertion unit, a zero-padding unit, and a control unit.

[0118] The insertion unit is used to determine multiple target frames that meet the preset TS packet requirements corresponding to the target DTMB-A single-frequency network system, and insert a MIP packet into the corresponding MPEG-2 transport stream for every target frame. A target frame contains N TS packets, and the value of N is adjusted according to the transmission rate of the TS bitstream, and N is an integer.

[0119] The zero-padding unit is used to determine the operating mode of the target DTMB-A single-frequency network system and the OFDM frame corresponding to each target frame in the multiple target frames based on multiple target frames, and to perform zero-padding operation on the tail of the service data pre-transmitted in each OFDM frame in the DTMB-A single-frequency network adapter of the target DTMB-A single-frequency network system according to the operating mode to obtain a zero-padding MPEG-2 transport stream.

[0120] The control unit is used to acquire the length information of each OFDM frame in the zero-padding MPEG-2 transport stream, and control 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 MIP packets to be less than 1 second according to the length information and the working mode. It also controls the TS code stream to be output at different rate levels according to different modulation modes of the target DTMB-A single-frequency network system through a preset buffer unit.

[0121] Optionally, in one embodiment of this application, the receiving module 200 includes: a determining unit, a detecting unit, and a calculating unit.

[0122] The determining unit is used to control the preset DTMB-A exciter to take each MIP packet in the service data stream as the first data packet of the OFDM frame in the target DTMB-A single-frequency network system, and to detect the service data stream.

[0123] The detection unit is used to obtain the start time of the OFDM frame corresponding to the MIP packet and the time difference of the PPS signal generated by the preset GPS receiver when a MIP packet is detected in the service data stream, and to extract the time tag and the maximum channel delay from the MIP packet.

[0124] The calculation unit is used to calculate the additional delay corresponding to the service data stream based on the start time, time difference, time tag, maximum channel delay, and preset additional delay calculation strategy.

[0125] Optionally, in one embodiment of this application, the transmitting module 400 includes: a synchronization unit, a multiplexing unit, and a frequency conversion unit.

[0126] The synchronization unit is used to align data frame information and control frame information that have passed through different network paths according to the additional delay, so as to synchronize the signal transmission time in the target DTMB-A single-frequency network system and generate a multiframe synchronization channel.

[0127] The multiplexing unit is used to multiplex data frame information and control frame information using the multiframe synchronization channel to synthesize multiframes, thereby obtaining multiplexed signals, and to perform baseband post-processing on the multiplexed signals to generate baseband transmission signals.

[0128] The frequency conversion unit is used to perform quadrature upconversion operation on the baseband transmission signal to convert the multiplexed signal into a radio frequency signal in the radio frequency band, and broadcast the radio frequency signal at the same time.

[0129] Optionally, in one embodiment of this application, the mathematical expression for the additional delay calculation strategy is:

[0130] STS+MD=Measured Delay+Additional Delay

[0131] Wherein, STS represents time tag; MD represents maximum channel delay; Measured Delay represents time difference; and Additional Delay represents additional delay.

[0132] It should be noted that the explanation of the above-described method for analyzing the DTMB-A single-frequency network system also applies to the analysis device of the DTMB-A single-frequency network system in this embodiment, and will not be repeated here.

[0133] The analysis apparatus for a DTMB-A single-frequency network system according to the embodiments of this application includes a pre-transmission service stream processing module, used to generate MIP packets according to the pre-transmission mode and GPS information of the target DTMB-A single-frequency network system, insert MIP packets into the pre-transmission service data, and calculate the number of service data packets and the amount of zero padding in each OFDM frame according to the pre-transmission mode to obtain a service data stream that meets the preset matching requirements with the DTMB-A transmission net code rate; a receiving module, used to receive the service data stream and control information through preset transmitting stations, and use each MIP packet in the service data stream as the first data packet of the OFDM frame in the target DTMB-A single-frequency network system, and extract the time tag and the maximum channel delay from the MIP packet to calculate the additional delay according to the time tag and the maximum channel delay; and a modulation module, used to process the service data stream. The system preprocesses the service data stream and control information, and performs scrambling, encoding, constellation mapping, and symbol interleaving on the preprocessed service data stream and control information to obtain the corresponding data processing results. It then performs 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. The transmission module generates a multiframe synchronization channel by adding a delay, and uses the multiframe synchronization channel to multiplex the data frame information and control frame information to synthesize a multiframe, obtaining the corresponding multiplexed signal. The multiplexed signal is then converted into a radio frequency signal in the radio frequency band for simultaneous broadcast transmission. This avoids synchronization system calculation delay errors caused by the waiting time of the DTMB-A modulator in processing the TS code stream, meeting the requirements of a single-frequency network in the DTMB-A system.

[0134] Figure 8 A schematic diagram of the structure of an electronic device provided in an embodiment of this application. The electronic device may include:

[0135] The memory 801, the processor 802, and the computer program stored on the memory 801 and capable of running on the processor 802.

[0136] When the processor 802 executes the program, it implements the analysis method of the DTMB-A single-frequency network system provided in the above embodiments.

[0137] Furthermore, electronic devices also include:

[0138] Communication interface 803 is used for communication between memory 801 and processor 802.

[0139] The memory 801 is used to store computer programs that can run on the processor 802.

[0140] The memory 801 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.

[0141] If the memory 801, processor 802, and communication interface 803 are implemented independently, then the communication interface 803, memory 801, and processor 802 can be interconnected via a bus to complete communication between them. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be divided into address buses, data buses, control buses, etc. For ease of representation, Figure 8 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0142] Optionally, in a specific implementation, if the memory 801, processor 802, and communication interface 803 are integrated on a single chip, then the memory 801, processor 802, and communication interface 803 can communicate with each other through an internal interface.

[0143] The processor 802 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of this application.

[0144] This application also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the above-described analysis method for a DTMB-A single-frequency network system.

[0145] This application also provides a computer program product, including a computer program, which, when executed, is used to implement the above-described analysis method for the DTMB-A single-frequency network system.

[0146] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0147] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0148] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or N executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0149] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0150] It should be understood that the various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. If implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0151] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0152] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0153] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

Claims

1. An analysis method for a DTMB-A single-frequency network system, characterized in that, Includes the following steps: MIP packets are generated based on the pre-transmission mode and GPS information of the target DTMB-A single-frequency network system, and the MIP packets are inserted into the pre-transmitted service data. At the same time, the number of service data packets and the number of zero padding in each OFDM frame are calculated according to the pre-transmission mode to obtain a service data stream that meets the preset matching requirements with the DTMB-A transmission net code rate. The service data stream and control information are received by each preset transmitting station, and each MIP packet in the service data stream is used as the first data packet of the OFDM frame in the target DTMB-A single-frequency network system. The time tag and maximum channel delay in the MIP packet are extracted to calculate the additional delay based on the time tag and the maximum channel delay. The service data stream and the control information are preprocessed, and the preprocessed service data stream and control information are scrambled, encoded, constellation mapped and symbol interleaved to obtain the corresponding data processing results. The data processing results and the preset PN-MC sequence are OFDM modulated and frequency grouped to generate the data frame information corresponding to the service data stream and the control frame information corresponding to the control information. The additional delay generates a multiframe synchronization channel, and the multiframe synchronization channel is used to multiplex the data frame information and the control frame information to synthesize a multiframe to obtain a corresponding multiplexed signal. The multiplexed signal is then converted into a radio frequency signal in the radio frequency band for synchronous broadcast transmission.

2. The method according to claim 1, characterized in that, The process of generating MIP packets based on the pre-transmission mode and GPS information of the target DTMB-A single-frequency network system, inserting the MIP packets into the pre-transmitted service data, and simultaneously calculating the number of service data packets and the amount of zero padding in each OFDM frame according to the pre-transmission mode to obtain a service data stream that meets the preset matching requirements with the DTMB-A transmission net code rate includes: Determine multiple target frames that meet the preset TS packet requirements corresponding to the target DTMB-A single-frequency network system, and insert a MIP packet into the corresponding MPEG-2 transport stream for every target frame. The target frame contains N TS packets, and the value of N is adjusted according to the transmission rate of the TS bitstream, and N is an integer. The operating mode of the target DTMB-A single-frequency network system and the OFDM frame corresponding to each target frame are determined based on the multiple target frames. Zero-padding is performed on the end of the service data to be pre-transmitted in each OFDM frame in the DTMB-A single-frequency network adapter of the target DTMB-A single-frequency network system according to the operating mode to obtain a zero-padding MPEG-2 transport stream. The length information of each OFDM frame in the zero-padding MPEG-2 transport stream is obtained, and the number of OFDM frames between adjacent MIP packets in the target DTMB-A single-frequency network system is controlled to be an integer and the interval between MIP packets is less than 1 second according to the length information and the working mode. The TS code stream is controlled to be output at different rate levels according to different modulation modes of the target DTMB-A single-frequency network system through a preset buffer unit.

3. The method according to claim 2, characterized in that, The process involves receiving the service data stream through preset transmitting stations, using each MIP packet in the service data stream as the first data packet of the OFDM frame in the target DTMB-A single-frequency network system, and extracting the time stamp and maximum channel delay from the MIP packet to calculate the additional delay based on the time stamp and the maximum channel delay, including: The preset DTMB-A exciter is controlled to treat each MIP packet in the service data stream as the first data packet of the OFDM frame in the target DTMB-A single-frequency network system, and to detect the service data stream. When a MIP packet is detected in the service data stream, the start time of the OFDM frame corresponding to the MIP packet and the time difference of the PPS signal generated by the preset GPS receiver are obtained, and the time tag and the maximum channel delay are extracted from the MIP packet. Based on the time difference, the time tag, the maximum channel delay, and the preset additional delay calculation strategy, the additional delay corresponding to the service data stream is calculated.

4. The method according to claim 1, characterized in that, The step of generating a multiframe synchronization channel through the additional delay, and using the multiframe synchronization channel to multiplex the data frame information and the control frame information to synthesize a multiframe to obtain a corresponding multiplexed signal, and converting the multiplexed signal into a radio frequency signal in the radio frequency band for simultaneous broadcast transmission of the radio frequency signal, includes: The data frame information and control frame information passing through different network paths are aligned according to the additional delay to synchronize the signal transmission time in the target DTMB-A single-frequency network system and generate the multiframe synchronization channel. The data frame information and the control frame information are multiplexed and synthesized into a multiframe using the multiframe synchronization channel to obtain the multiplexed signal, and the multiplexed signal is subjected to baseband post-processing to generate a baseband transmission signal. The baseband transmission signal is subjected to orthogonal upconversion to convert the multiplexed signal into a radio frequency signal in the radio frequency band, and the radio frequency signal is broadcast and transmitted simultaneously.

5. The method according to claim 3, characterized in that, The mathematical expression for the additional delay calculation strategy is: STS+MD=Measured Delay+Additional Delay Wherein, STS represents the time tag; MD represents the maximum channel delay; Measured Delay represents the time difference; and Additional Delay represents the additional delay.

6. An analysis device for a DTMB-A single-frequency network system, characterized in that, include: The pre-transmission service stream processing module is used to generate MIP packets based on the pre-transmission mode and GPS information of the target DTMB-A single-frequency network system, insert the MIP packets into the pre-transmission service data, and calculate the number of service data packets and the number of zero padding in each OFDM frame according to the pre-transmission mode, so as to obtain a service data stream that meets the preset matching requirements with the DTMB-A transmission net code rate. The receiving module is used to receive the service data stream and control information through preset transmitting stations, and to take each MIP packet in the service data stream as the first data packet of the OFDM frame in the target DTMB-A single-frequency network system, and to extract the time tag and the maximum channel delay in the MIP packet, so as to calculate the additional delay based on the time tag and the maximum channel delay; The modulation module is used to preprocess the service data stream and the control information, and to perform scrambling, encoding, constellation mapping and symbol interleaving on the preprocessed service data stream and control information to obtain the corresponding data processing results. The module also performs 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. The transmitting module is used to generate a multiframe synchronization channel through the additional delay, and to use the multiframe synchronization channel to multiplex the data frame information and the control frame information to synthesize a multiframe to obtain a corresponding multiplexed signal, and to convert the multiplexed signal into a radio frequency signal in the radio frequency band for synchronous broadcast transmission of the radio frequency signal.

7. The apparatus according to claim 6, characterized in that, The pre-transmission service stream processing module includes: An insertion unit is used to determine multiple target frames that meet the preset TS packet requirements corresponding to the target DTMB-A single-frequency network system, and to insert a MIP packet into the corresponding MPEG-2 transport stream for every target frame. The target frame contains N TS packets, and the value of N is adjusted according to the transmission rate of the TS bitstream, and N is an integer. The zero-padding unit is used to determine the operating mode of the target DTMB-A single-frequency network system and the OFDM frame corresponding to each target frame in the multiple target frames based on the multiple target frames, and to perform zero-padding operation on the end of the service data to be pre-transmitted in each OFDM frame in the DTMB-A single-frequency network adapter of the target DTMB-A single-frequency network system according to the operating mode to obtain a zero-padding MPEG-2 transport stream. The control unit is used to acquire the length information of each OFDM frame in the zero-padding MPEG-2 transport stream, and control 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 MIP packets to be less than 1 second according to the length information and the working mode. It also controls the TS code stream to be output at different rate levels according to different modulation modes of the target DTMB-A single-frequency network system through a preset buffer unit.

8. An electronic device, characterized in that, include: A memory, a processor, and a computer program stored in the memory and executable on the processor, the processor executing the program to implement the analysis method for a DTMB-A single-frequency network system as described in any one of claims 1-5.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by the processor to implement the analysis method for the DTMB-A single-frequency network system as described in any one of claims 1-5.

10. A computer program product, comprising a computer program, characterized in that, The computer program is executed to implement the analysis method for the DTMB-A single-frequency network system as described in any one of claims 1-5.

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