JP2019522930A - Transmitting apparatus and transmitting method - Google Patents

Abstract

A mobile service capacity is limited once a tuner is set. A transmission apparatus that transmits payload data using OFDM symbols that are orthogonal frequency division multiplexed, receives the payload data transmitted from a plurality of different channels, and receives each of the channels for a plurality of time frames. A frame builder configured to frame payload data received from a plurality of payload data frames for transmission, and a frame-synchronized OFDM symbol, one or more first signaling for each of the plurality of payload data frames A modulation unit configured to generate an OFDM symbol, one or more second signaling OFDM symbols, and modulate one or more payload OFDM symbols according to payload data received from each channel; Payload Each of the plurality of transmission frames includes one or more payload OFDM symbols, and frame-synchronized OFDM for the one or more payload OFDM symbols. A symbol followed by the one or more first signaling OFDM symbols followed by the one or more second signaling OFDM symbols, the frame-synchronized OFDM symbol and the one or more The first signaling OFDM symbol is transmitted with a bandwidth equal to the radio frequency transmission bandwidth, and the one or more second signaling OFDM symbols and the one or more payload OFDM symbols are transmitted with the radio frequency transmission band. One or more of the above sent in width The second signaling OFDM symbol and the one or more payload OFDM symbols are each frequency divided to provide a plurality of frequency segments, each of the plurality of frequency segments carrying payload data from different channels, The one or more second signaling OFDM symbols in each frequency segment are for detecting and recovering the payload data transmitted by the plurality of frequency segments from the one or more payload OFDM symbols for each channel. Transmitting one instance of the plurality of physical layer signaling instances, wherein the one or more first signaling OFDM symbols are first signaling data for detecting the second signaling OFDM symbol. A transmission device for transmitting data is provided. [Selection] Figure 2

Description

  The present disclosure relates to a transmission apparatus and a method of transmitting payload data using orthogonal frequency division multiplexing (OFDM) symbols.

  This application claims priority under the Paris Convention of British Patent Application No. 1611071.0, the entire contents of which are hereby incorporated by reference.

  There are many examples of wireless communication systems that perform data communication using orthogonal frequency division multiplexing (OFDM). For example, a television system configured to operate according to the Digital Video Broadcasting (DVB) standard uses OFDM for terrestrial and cable transmissions. OFDM can generally be described as providing K narrowband subcarriers (where K is an integer) modulated in parallel. Each subcarrier communicates modulated data symbols such as quadrature amplitude modulation (QAM) symbols and quadrature phase shift keying (QPSK) symbols. The subcarrier is modulated in the frequency domain, converted into the time domain, and transmitted. Since data symbols are communicated in parallel on subcarriers, the same modulation symbol can be communicated on each subcarrier for a long time. The subcarriers are modulated in parallel at the same time, so that the modulated carriers together constitute an OFDM symbol. Therefore, the OFDM symbol includes a plurality of subcarriers, and each subcarrier is modulated simultaneously and has a different modulation symbol. During transmission, a guard interval inserted with a cyclic prefix of the OFDM symbol precedes the OFDM symbol. When present, the guard interval is provided so as to absorb any echoes of the transmission signal that may be caused by multipath.

ATSC Standard: A / 321, System Discovery and Signaling (ATSC Standard: A / 321, System Discovery and Signaling) In a publication titled ^[1] , as Advanced Television Systems Committee (ATSC) 3.0 For known television systems, it has been proposed to include a preamble in a transmitted television signal carrying a broadcast digital television program. The preamble includes a so-called “bootstrap” signal. The bootstrap signal is intended to provide the receiving device with a portion of the transmitted signal that is more likely to detect and thus can function as a signal for initial detection. This is because a broadcasting station expects not only to broadcast television but also to provide a plurality of services within the range of broadcast signals.

  However, in ISDB-T, which is the current standard of a broadcasting network that employs OFDM in which a service is time division multiplexed (TDM) in a single channel, once a tuner is set, the capacity of the mobile service is limited. There is a problem. As the demand for mobile TV increases, these problems become increasingly apparent.

  The next standard, ISDB-T3, proposes to design a frame structure that can be configured for frequency division multiplexing (FDM) or TDM. Such a frame structure is proposed herein and defined with respect to embodiments of the technology.

  Further aspects and embodiments of the present disclosure are provided in the appended claims including a transmission apparatus and a transmission method.

  According to embodiments of the present disclosure, a transmission apparatus that transmits payload data using OFDM symbols that are orthogonal frequency division multiplexed, receives the payload data transmitted from a plurality of different channels, and A frame builder configured to frame payload data received from each channel with respect to a time frame into a plurality of payload data frames for transmission, and for each of the plurality of payload data frames, one frame synchronization OFDM symbol, one or Generated a plurality of first signaling OFDM symbols, one or more second signaling OFDM symbols, and configured to modulate one or more payload OFDM symbols with payload data received from each of the channels Modulator and above Each of the plurality of transmission frames includes one or more payload OFDM symbols, and each of the plurality of transmission data frames includes one or more payload OFDM symbols. A frame-synchronized OFDM symbol, followed by the one or more first signaling OFDM symbols, followed by the one or more second signaling OFDM symbols, the frame-synchronized OFDM symbol and the 1 The one or more first signaling OFDM symbols are transmitted with a bandwidth equal to the radio frequency transmission bandwidth, and the one or more second signaling OFDM symbols and the one or more payload OFDM symbols are Transmitted in the radio frequency transmission bandwidth, The one or more second signaling OFDM symbols and the one or more payload OFDM symbols are each frequency-divided to provide a plurality of frequency segments, each of the plurality of frequency segments being from different channels. The one or more second signaling OFDM symbols in each frequency segment transmit payload data, and the payload data transmitted by the plurality of frequency segments from the one or more payload OFDM symbols is transmitted for each channel. Transmitting one of a plurality of instances of physical layer signaling for detecting and reconstructing, wherein the one or more first signaling OFDM symbols are for detecting the second signaling OFDM symbol First A transmission device for transmitting signaling data is provided.

  The present disclosure is disclosed in copending patent applications PCT / GB2014 / 050869, GB1305805.2, PCT / GB2014 / 050868, GB1305797.1, GB1305799, the entire contents of which are incorporated herein by reference. No. 7, US14 / 226937, PCT / GB2014 / 050870, GB1305795.5, PCT / GB2014 / 050954, GB1312048.0, TW103121570, PCT / GB2014 / 051679, EP13170706.9, PCT / By EP2014 / 061467, GB1403392.2, GB14050337.1, TW103121568, PCT / GB2014 / 051922 and GB1420117.2 It is supported.

  In the appended claims, various further aspects and features of the present disclosure are defined, including a method for transmitting payload data.

FIG. 1 is a schematic diagram showing a configuration of a broadcast transmission network. FIG. 2 is a schematic block diagram illustrating an exemplary transmission chain for transmitting broadcast data over the transmission network of FIG. FIG. 3 is a schematic diagram illustrating OFDM symbols in the time domain including a guard interval. FIG. 4 is a schematic block diagram illustrating an exemplary receiving apparatus for receiving data broadcast by the broadcast transmission network of FIG. 1 using OFDM. FIG. 5 is a schematic diagram illustrating a transmission frame for simultaneously transmitting payload data including a plurality of services in a plurality of segments separated in a frequency domain according to an embodiment of the present technology. FIG. 6 is a schematic block diagram illustrating a part of the transmission apparatus illustrated in FIG. 2 for transmitting a frame synchronization OFDM symbol according to an embodiment of the present technology. FIG. 7 is a schematic diagram illustrating a pseudo-noise sequence generation circuit used for generating a frame-synchronized OFDM symbol according to an embodiment of the present technology. FIG. 8 is a schematic diagram illustrating a frame-synchronized OFDM symbol in the frequency domain according to an embodiment of the present technology. FIG. 9 is a flowchart illustrating an exemplary operation of the transmission device when generating one or more frame-synchronized OFDM symbols by cyclically shifting a time-domain symbol sequence according to an embodiment of the present technology. FIG. 10 is a schematic diagram illustrating a time domain structure of a frame synchronization OFDM symbol according to an embodiment of the present technology. FIG. 11 is a schematic diagram illustrating a second time domain of the first signaling OFDM symbol according to an embodiment of the present technology. FIG. 12 is a schematic block diagram illustrating an exemplary receiver for detecting and recovering signaling from one or more frame-synchronized OFDM symbols. FIG. 13 is a schematic block diagram illustrating a receiving apparatus for detecting a frame-synchronized OFDM symbol including specifying a trigger time for performing a forward Fourier transform on an OFDM symbol according to an embodiment of the present technology. FIG. 14 is a schematic block diagram illustrating a correlation unit configured to detect a frame-synchronized OFDM symbol according to an embodiment of the present technology. FIG. 15 is a flowchart illustrating detection of a use sequence and a frequency offset in a reception apparatus when generating a frame synchronization OFDM symbol and a first signaling OFDM symbol according to an embodiment of the present technology. FIG. 16 is a schematic block diagram illustrating a part of a receiving apparatus such as the example illustrated in FIG. 4 configured to detect a relative cyclic shift of a signature sequence according to an embodiment of the present technology. FIG. 17 is a schematic block diagram illustrating a part of a receiving apparatus such as the example illustrated in FIG. 4 configured to detect a relative cyclic shift of a signature sequence according to an embodiment of the present technology. FIG. 18 shows the block error rate versus symbol-to-noise ratio showing the performance difference between the method using conjugate multiplication as shown in FIGS. 16 and 17 and the frequency domain decoding algorithm using division according to an embodiment of the present technology. It is a graph. FIG. 19 is a diagram illustrating reception of segmented OFDM according to an embodiment of the present technology. FIG. 20 is a schematic block diagram illustrating a part of a narrowband receiver configured to detect a relative cyclic shift of a signature sequence according to an embodiment of the present technology.

  Hereinafter, embodiments of the present disclosure will be described by way of example with reference to the accompanying drawings. In each figure, the same reference numerals are given to the same parts.

  Embodiments of the present disclosure can form a transmission network for transmitting signals representing video data and audio data, for example, a broadcast network for transmitting a television signal to a television receiver. It can be constituted as follows. In some examples, the device for receiving audio / video of the television signal may be a mobile device that receives the television signal on the move. In another example, audio / video data may be received by a conventional television receiver. The television receiver may be a fixed type or connected to one or a plurality of fixed antennas.

  The television receiving device may or may not include an integrated display for television images, and may be a recorder device including a plurality of tuners and a demodulator. The antenna may be incorporated in the television receiver. A connected antenna or a built-in antenna may be used to facilitate reception of a signal that is different from a television signal. Accordingly, embodiments of the present disclosure are configured to facilitate different types of devices in different environments to receive audio / video data representing television programs.

  It will be appreciated that receiving a television signal using a mobile device while traveling can be more difficult because the radio reception conditions are significantly different from those of a conventional television receiver receiving input from a fixed antenna.

  An example of a television broadcasting system is shown in FIG. A broadcast television base station 1 shown in FIG. 1 is connected to a broadcast transmission device 2. The broadcast transmission device 2 transmits a signal received from the broadcast television base station 1 within the coverage area of the broadcast network. The television broadcast network shown in FIG. 1 can operate as a so-called multi-frequency network. In a multi-frequency network, each broadcast television base station 1 transmits a signal at a frequency different from the frequency of another adjacent broadcast television base station 1. The television broadcast network shown in FIG. 1 can also operate as a so-called single frequency network. In the single frequency network, each broadcast television base station 1 transmits a radio signal for simultaneously transmitting audio / video data so that the television receiver 4 and the mobile device 6 within the coverage area of the broadcast network can receive. In the example shown in FIG. 1, a signal transmitted from the broadcast television base station 1 is transmitted using orthogonal frequency division multiplexing (OFDM), so that even if a signal is transmitted from a different broadcast television base station 1. Each broadcast transmitting apparatus 2 can be configured to transmit the same signal that can be synthesized by the television receiving apparatus. The interval between broadcast television base stations 1 is such that the propagation time between signals transmitted by different broadcast television base stations 1 is shorter than or substantially not longer than the guard interval preceding the transmission of each OFDM symbol. In some cases, the receiving device 4 and the mobile device 6 can receive an OFDM symbol, and can further recover data from the OFDM symbol by combining signals transmitted from different broadcast television base stations 1. it can. Examples of broadcast network standards that employ OFDM in this way include DVB-T, DVB-T2, and ISDB-T.

  FIG. 2 is an exemplary block diagram illustrating a transmission device that forms part of the broadcast television base station 1 for transmitting data from an audio / video source. In FIG. 2, different audio / video channels 20, 22, and 24 generate different audio / video data representing television programs or content. The audio / video data is encoded and modulated, and then supplied to the frame builder 26. The frame builder 26 is configured to form data transmitted in a payload data frame or a transmission time frame corresponding to a time division unit. In each payload data frame, physical layer signaling data is provided by the physical layer data block 28, and is added to each payload data frame and transmitted. That is, for each of the audio / video channels 20, 22, and 24, a plurality of payload data for each of a plurality of time frames corresponding to a plurality of transmission frames generated in the transmission signal by the transmission apparatus shown in FIG. Audio / video data is formed in the frame. The frame is one or more data for transmitting audio / video data generated by a time division or frequency division interval having a preamble to which physical layer signaling is transmitted, and audio / video channels 20, 22, and 24. A transmission interval may be included. The data may be interleaved and formed into symbols before being supplied to the OFDM modulation unit 30. The output of the OFDM modulation unit 30 is passed through the guard insertion unit 32 that inserts a guard interval, and the obtained signal is supplied to the transmission unit 40. The signal is transmitted from the transmission unit 40 through the antenna 42. The signaling and synchronization information generated by the signaling and synchronization generation unit 34 may be provided to the guard insertion unit 32. Signaling information transmitted together with the frame synchronization signal and the first signaling symbol is generated by the signaling information unit 36 and supplied to the synchronization signal generation unit 38. The synchronization signal generator 38 generates a frame synchronization signal and a first signaling symbol. As described below, the signaling information may be expressed as a signature sequence that modulates the first signaling OFDM symbol relative to the signature sequence of the frame-synchronous OFDM symbol as a relative cyclic shift of the frame-synchronous OFDM symbol in the time domain.

  Similar to conventional configurations, OFDM is configured to generate symbols in the frequency domain. In the frequency domain, data symbols to be transmitted are mapped to subcarriers. The subcarriers are converted to the time domain using an inverse Fourier transform. The inverse Fourier transform may constitute a part of the OFDM modulation unit 30. In this way, data to be transmitted is formed in the frequency domain and transmitted in the time domain. As shown in FIG. 3, each time domain symbol is generated by a valid portion of duration Tu seconds and a guard interval of duration Tg seconds. The guard interval is generated by copying a part of the effective part of the symbol having a duration Tg in the time domain. However, the copied portion may be generated from the end of the symbol. By correlating the effective part of the time-domain symbol with the guard interval, the receiving device can be configured to detect the starting part of the effective part of the OFDM symbol. Starting from this starting portion, the sample of the time domain symbol can be converted to the frequency domain by fast Fourier transform. Transmission data can be restored from the frequency domain. Such a receiving apparatus is shown in FIG.

  In FIG. 4, the receiving antenna 50 is configured to detect an RF signal that has passed through the tuner 52 and converted into a digital signal by the analog / digital converter 54. Thereafter, the guard interval is removed by the guard interval removing unit 56. After detecting an optimal position for performing Fast Fourier Transform (FFT) and converting the time domain sample to the frequency domain, the FFT unit 58 converts the time domain sample to form a frequency domain sample. The sample is supplied to the channel estimation and correction unit 60. The channel estimation and correction unit 60 estimates a transmission channel used for equalization, for example, using pilot subcarriers embedded in an OFDM symbol. After excluding the pilot subcarriers, all subcarriers including data are supplied to the demapper unit 62. The demapper unit 62 extracts data bits from the subcarriers of the OFDM symbol. These data bits are then supplied to a deinterleaver 64 that deinterleaves the subcarrier symbols. The data bits are then supplied to the bit deinterleaver 66. The bit deinterleaver 66 performs deinterleaving so that the error correction decoder can correct errors using redundant data included in the forward error correction encoding process, for example, according to the error correction operation.

Framing Structure FIG. 5 shows a schematic diagram of a framing structure of a frame according to an embodiment of the present technology that can be transmitted and received in the system described with reference to FIGS. FIG. 5 shows the proposed general structure of a transmission signal for transmitting data from different channels. For example, this structure can be used to transmit different television channels within an ISDB-T3 frame. As shown in FIG. 5, the transmission frame includes the following.
A frame-synchronized OFDM symbol 501 used by the receiver to detect the start of the frame and estimate the carrier frequency offset.
A first preamble containing one or more (m) special OFDM symbols. The special OFDM symbol may be referred to as the first signaling OFDM symbol 502 (P1). The first signaling OFDM symbol 502 (P1) carries initial signaling information related to the structure of the second preamble.
A second preamble that includes one or more OFDM symbols. The OFDM symbol may be referred to as second signaling OFDM symbols 504 and 505 (P2) that carry physical layer (layer 1) parameters. The parameter describes how the payload is transmitted with a post-preamble waveform for all segments of the frame. Appropriate parameters are described, for example, in the DVB standard and ATSC 3.0 physical layer standard draft at the filing date. In embodiments, the signaling data transmitted by each of the one or more second signaling OFDM symbols in the frame is the same. In one example, this may be structured in a loop that transmits data for each segment. That is, the different frequency segments 507.1, 507.2, and 507.3 of the second signaling OFDM symbols 504 and 505 (P2) are respectively for frequency segments 507.1, 507.2, and 507.3. An example of band information defining the structure of the payload OFDM symbol 506.
A post-preamble section containing multiple payload OFDM symbols 506; The payload OFDM symbol 506 includes a service formed from audio / video data that transmits payload and is generated by different channels and divided into physical layer pipes (PLP). The number of payload OFDM symbols 506 may be signaled by the second signaling OFDM symbols 504 and 505. The term physical layer pipe (PLP) is used to identify a channel of audio / video data that can be recovered from a transmission frame.
Each channel provided by frequency segments 507.1, 507.2, and 507.3 of the payload OFDM symbol is framed before the next frequency-synchronized OFDM symbol 511 and the first (P1) signaling OFDM symbol 512. Terminate with a close symbol (FCS) 508.

  In embodiments, the frame frequency synchronization OFDM symbol 501 is immediately followed by one or more first signaling OFDM symbols 502. In embodiments, one or more second signaling OFDM symbols 504 and 505 immediately follow the last symbol of one or more first signaling OFDM symbols 502 in the frame. In embodiments, the payload OFDM symbol 506 immediately follows the last symbol of one or more second signaling OFDM symbols 504 and 505 in the frame.

  As described above, the transmission frame is further divided into M frequency segments 505.1, 507.2, and 507.3, which also divides each OFDM symbol of the frame. The number M of segments per frame is configurable and is transmitted as a signal by the first signaling OFDM symbol.

  The frame-synchronized OFDM symbol and the first signaling OFDM symbol are essentially wideband because they are configured to span the entire channel bandwidth. However, these symbols can be detected and decoded by both a wideband receiver whose bandwidth extends over the entire channel and a narrowband receiver whose bandwidth is the same as one of the M segments. Both the second signaling OFDM symbol and the payload OFDM symbol are separately modulated for each segment and then concatenated in the frequency domain in segment order prior to conversion to the time domain by IDFT. Therefore, when performing frequency segmentation, the second signaling OFDM symbol and the payload OFDM symbol must be decoded for each segment.

  In embodiments, the radio frequency transmission bandwidth 514 of the transmitted signal shown in FIG. 5 represents the bandwidth for a frame of about 6 Mhz or about 8 Mhz. However, it will be appreciated that these are merely examples and that other radio frequency transmission bandwidths may be used so that embodiments of the present disclosure are not limited to these bandwidths.

  In the following paragraphs, how the first signaling OFDM symbol can be configured, how the first signaling OFDM symbol can transmit signaling information, the first signaling OFDM symbol transmitted Not only how the information to be decoded is decoded in the receiving apparatus, but also how the frame-synchronized OFDM symbol is configured in the transmitting apparatus and how the frame-synchronized OFDM symbol can be detected in the receiving apparatus Describe.

Synchronization Signal FIG. 6 is a schematic block diagram of a portion of the transmission apparatus shown in FIG. 2 configured to transmit a frame synchronization signal. In FIG. 6, the signature sequence generation unit 600 is configured to generate a signature sequence that is mapped to subcarriers of an OFDM symbol that constitutes a frame synchronization OFDM symbol by the subcarrier mapping and zero padding unit 602. The frequency domain signal is then transformed into the time domain by the inverse Fourier transform unit 604. The signaling information transmitted by the frame synchronization signal is supplied to the cyclic shift unit 606 through the first input 605. Cyclic shift unit 606 also receives a time-domain OFDM symbol representing a frame-synchronized OFDM symbol with second input 607. In various embodiments of the present technology, the combination of the operation of the cyclic shift unit 606 and its input may correspond to the signaling and synchronization generation unit 34 illustrated in FIG. As described below, the signaling information is represented as a signature sequence that modulates the first signaling OFDM symbol relative to the signature sequence of the frame-synchronous OFDM symbol as a relative cyclic shift of the frame-synchronous OFDM symbol in the time domain. The first signaling OFDM symbol is then supplied to the guard interval insertion unit 608. The guard interval insertion unit 608 adds a guard interval to the frame synchronization OFDM symbol in a format in which the OFDM symbols constituting the frame synchronization OFDM symbol are transmitted by the transmission unit 609.

The frame-synchronized OFDM symbol has the same structure as the first ATSC 3.0 bootstrap symbol described in A / 321 ^[2] . The frame synchronization OFDM symbol is a 2048p FFT size OFDM symbol. The value of p can be any of {0.25, 0.5, 1, 2, 4}, which allows frame-synchronized OFDM symbols to be {512, 1K, 2K, 4K, 8K} FFT sizes, respectively. OFDM symbols.

  As shown in FIG. 6, signature sequence generation section 600 includes a pseudo random sequence generation section 610 and a Zadoff-Chu (ZC) sequence generation section 612 that are used to generate a signature sequence. These two sequences are multiplied by a multiplication unit 614, and the multiplied sequences are mapped to subcarriers of the OFDM symbol by a subcarrier mapping and zero padding unit 602. As shown in FIG. 6, the seed value of the pseudo-random sequence generation unit 610 is supplied by a first input 620, and the second input 622 provides an indication of the route of the Zadoff-Chu sequence generation unit 612. A ZC sequence is generated using Equation 1 below.

(Q is defined as the root of the ZC sequence.)

  As described with reference to FIG. 6, the frame-synchronized OFDM symbol includes a Zadoff-Chou (ZC) sequence coefficient multiplied by the positive and negative coefficients generated by the pseudo noise (PN) sequence generation unit shown in FIG. It is configured in the frequency domain by mapping to the carrier. Accordingly, the multiplied sequences according to the embodiments are described as (ZC * PN) sequences.

FIG. 7 is a schematic diagram illustrating a pseudo noise generation circuit 610 that constitutes a part of the signature sequence generation unit 600 illustrated in FIG. 6 that is used when generating a frame-synchronized OFDM symbol according to an embodiment of the present technology. . The PN sequence is generated using the following (multinomial) expression 2 by the generation circuit shown in FIG. At the beginning of each frame, each element 701, 702, 704, and 706 (r _I ) is initialized with the selected 16-bit seed g. This seed takes the form shown in Equation 3.

(However, each bit 711, 712, 714, 716, 718, and 719 (g _i ) has a binary value of either 0 or 1. These are added together to form a 16-bit seed g. Combined by elements 721, 722, 724, and 726)

  FIG. 8 shows mapping of (ZC * PN) sequences for symmetrically forming signature sequences on OFDM symbols.

  As shown in FIG. 8, in the frequency domain, the frame synchronization signal can be regarded as including a bisection 810 of a symmetric Zadoff-Chu (ZC) sequence. Each symbol in the Zadoff-Chu sequence is configured to modulate an active carrier 812. Correspondingly, the PN sequence is configured to modulate subcarriers as shown by line 814. Since the other subcarriers of the frame synchronization signal are not used, it is set to zero, for example, as shown at the ends of the frame synchronization signals 820 and 822.

The length of the (ZC * PN) sequence N _a is a configurable parameter called the number of useful subcarriers per frame-synchronized OFDM symbol. This, (ZC * PN) coefficients are mapped only to N _a subcarrier in the center of the frame synchronization OFDM symbols (in the low band and high band edge of the symbol) that other subcarriers are set to zero Means. The (ZC * PN) series has mirror symmetry in its configuration, and the center coefficient is set to zero.

As shown in FIG. 8, the ZC sequence and the PN sequence are mapped to OFDM subcarriers so as to be mirror symmetric with respect to the central DC subcarrier of the OFDM symbol. The subcarrier value of the nth symbol in frame synchronization (0 ≦ n <N _B ) can be calculated as in the following equations 4 and 5. _However, an _{N H = (N ZC -1)} / 2, N B is the number of symbols, p (k) is an element of the PN sequence. A ZC sequence is determined by its route q. The root q may be the same for each symbol, but the PN sequence increases with each symbol.

  For the last symbol, the phase of the subcarrier value of that particular symbol is inverted (ie, rotated 180 °). This provides a clear end indication of frame synchronization and preamble signals. This is provided when there is another symbol, in which case the receiving device provides a clear indication of the last OFDM symbol. That is, any number of synchronization and signaling OFDM symbols can be used. Therefore, the receiving apparatus can detect the phase inversion, and thus can detect the end of the frame synchronization signal.

  In one example, signaling data can be transmitted in the first signaling symbol by performing a data decision cyclic shift of the frame-synchronized OFDM symbol in the time domain. This is done by the cyclic shift block shown in FIG. The processes for transmitting the signaling bits are collectively shown in FIG.

  In FIG. 9, in step S900, the sequence generation unit 600 forms a frequency domain sequence in the frequency domain. In step S902, the IFFT unit 604 performs inverse Fourier transform to transform the frequency domain signal into the time domain. In this way, in step S904, the series is formed in the time domain. As shown in step S906, signaling bits are formed and then interpreted as relative cyclic shift values in step S908. In step S910, the relative shift value is converted into an absolute shift value. As indicated by arrow S912, the time domain sequence formed in step S904 is then shifted according to the absolute cyclic shift determined in step S910. Finally, in step S914, a time domain sequence to be transmitted is generated.

In one example of a time domain structure , each frame-synchronized OFDM symbol is formed from three parts called A, B, and C by the transmitter. As described above, an OFDM symbol is usually formed with a guard interval generated by copying a section of the OFDM symbol in the time domain as a preamble for the OFDM symbol in order to consider multipath reception in the receiving apparatus. Each frame-synchronized OFDM symbol is formed in one of two ways. The frame-synchronized OFDM symbol and the first signaling symbol formed by different methods in the time domain are shown in FIGS. As shown in FIGS. 10 and 11, the data transmission part of the symbol that is the original configuration of the OFDM symbol before the guard interval is added is represented as section A (1001, 1101). Therefore, section A (1001, 1101) is derived as a 2048p point IFFT with a frequency domain structure with or without the above-described cyclic shift to represent signaling bits transmitted by frame-synchronized OFDM symbols. However, section A (1001, 1101) is an effective portion of a symbol composed of 2048p samples formed by IFFT. Section B (1002,1102) and C (1004,1104) is a frequency shift of ± f _delta equal to a sub-carrier interval to be introduced to a sample of section B (1002,1102) by a transmitting device, section A (1001, 1101) is composed of samples taken from the end and correspondingly removed by the receiving device. Each frame-synchronized OFDM symbol and the first signaling symbol consist of 3072p samples consistently. However, section A (1001, 1101) consists of 2048p samples, section C (1004, 1104) consists of 520p samples and sections A (1001, 1101) 1006 and 1008, 1106 and 1108, and section B ( 1002,1102) consists of 1006 and 1106 Metropolitan interval last sample and the frequency shift of ± f _delta of 504p is applied C (1004,1104).

Frame synchronization OFDM symbol, it is provided for the synchronization detection of a specific (ZC * PN) sequence to be transmitted, employs a C-A-B structure as shown in FIG. 10, the section of the frequency shift of + f _delta Applies to B (1002). By selecting (ZC * PN), the major and minor standards in use, the alert status that can be used to provide emergency alert conditions, the identification of the transmitter, the location of the transmitter, etc. can be signaled it can.

The one or more first signaling symbols carry a B-C-A structure as shown in FIG. 11 that includes the final symbols that are phase-inverted to carry signaling information and provide termination of the preamble signal as described above. adopted to apply the frequency shift of -f _delta in section B (1102).

  Frame-synchronized OFDM symbols shall be used for initial time synchronization, and other aspects of the system may be signaled by selection of ZC route and / or PN seed parameters. This symbol does not signal any additional information. The cyclic shift of this symbol is always 0.

The differentially encoded absolute cyclic shift M _n (0 ≦ M _n <N _FFT ) is applied to the nth first signaling OFDM symbol and is absolute to the symbol n−1 modulo the length of the time domain sequence. Calculated by summing the cyclic shift and the relative cyclic shift for symbol n.

  Thereafter, an absolute cyclic shift is applied to obtain a shifted time domain sequence from the output of the IFFT operation.

Frame synchronization at the receiver: The broadband receiver needs to detect the presence of a frame-synchronized OFDM symbol as a marker for the start of the frame. The receiving device will be preset with appropriate values for p, N _a , and Δf. Frame-synchronized OFDM symbols can be detected in the time domain, for example, processing to find an arbitrary carrier frequency offset and / or another (ZC * PN) sequence to identify which sequence is being used. Must be performed in the frequency domain. However, detection of frame-synchronized OFDM symbols is equivalent to detection of frame start.

  FIG. 12 is a schematic block diagram illustrating application of the receiving apparatus shown in FIG. 4 when operating to detect the presence of frame-synchronized OFDM symbols. As shown in FIG. 4, the signal detected by the antenna 50 is supplied to the RF tuner 52 and then supplied to the A / D converter 54. Thereafter, the received digital sampling signal is supplied to the forward Fourier transform processing unit 58 and also supplied to the first input of the switch 1201. The switch 1201 is controlled by the control unit 1202 and switches the received digital sampling signal between the frame synchronization detection unit 1204 and the second frame synchronization processing unit among the two frame synchronization processing units 1206 and 1210. The frame synchronization detection unit 1204 performs FFT processing via the channel 1208 to identify the most effective part of the received signal converted from the time domain to the frequency domain for the purpose of verifying the frame synchronization signal and restoring the signaling data. A trigger signal supplied to the unit 58 is generated. The received signal converted into the frequency domain is provided to the first frame synchronization processing unit 1210 by the output of the FFT processing unit 58. The first frame synchronization processor 1210 is configured to generate a first estimate of the channel transfer function (CTF) H (z) in the output channel 1212.

  An exemplary detection unit for a frame-synchronized OFDM symbol of a preamble signal is shown in FIG. As described above, it has a C-A-B structure in which only the first frame synchronization OFDM symbol is transmitted for initial synchronization. FIG. 13 is an exemplary block diagram illustrating a frame synchronization OFDM symbol detection unit. As shown in FIG. 13, the received discrete time signal r (n) is supplied to the delay unit 1301 and the C-A-B structure detection unit 1302. The C-A-B structure detection unit 1302 generates an estimated value of the fine frequency offset (FFO) based on the first output 1304. The fine frequency offset is a frequency shift smaller than the OFDM symbol subcarrier interval and may occur during transmission of a frame-synchronized OFDM symbol. The output from the second channel 1306 is a timing trigger instruction indicating the period of the received OFDM symbol, and is converted by the FFT processing unit 58 so as to capture as much energy as possible in the received OFDM frame synchronization OFDM symbol. Is done. However, the total frequency offset is removed by the multiplier 1308 before the received frame-synchronized OFDM symbol is converted to the frequency domain. The multiplier 1308 receives the received signal delayed from the delay unit 1301 by the first input, and receives the reciprocal of the total frequency offset formed by the adder 1310 and the tone generator 1312 by the second input. The total frequency offset is one of a fine frequency offset (FFO) estimated by the C-A-B structure detection unit 1302 and supplied to the first input and an integer frequency offset (IFO) estimated by the frame synchronization signal processing unit 1310. Alternatively, the adder 1310 is formed from both. The total frequency offset is input to the tone generator 1312 and causes the tone generator 1312 to generate a sine wave tone at a frequency equal to the total frequency offset. Frame synchronization signal processing section 1210 generates an IFO by correlating frequency domain subcarriers with a regenerated signature sequence generated by a combination of ZC sequences modulated with PN sequences. Thereafter, the IFO is estimated using the position of the peak of the correlation output. The IFO is a displacement in the frequency domain of a large number of subcarriers with respect to a reference frequency in the main frequency band of the frame synchronization signal. In this way, the total frequency offset is estimated and removed by the multiplier 1308 and the tone generator 1312 from the FFO estimated by the structure detector 1302 and the IFO estimated by the frame synchronization signal processor 1210.

  As described above, the C-A-B structure detection unit 1302 shown in FIG. 13 for detecting the frame-synchronized OFDM symbol generates an FFO and determines the effective portion of the input signal burst for forward Fourier transform (FFT). Used to indicate.

  FIG. 14 is a schematic block diagram illustrating a correlation unit configured to detect a frame-synchronized OFDM symbol according to an embodiment of the present technology. This detection indicates the start of the A portion of the frame-synchronized OFDM symbol where FFT can be performed. The remainder of this process includes the detection of the (ZC * PN) sequence used in the frame-synchronized OFDM symbol, followed by the decoding of the signaling parameters transmitted by the next first signaling OFDM symbol. Each of the next first signaling OFDM symbols uses a known segment of the same ZC and PN sequences as its frame-synchronized OFDM symbol. Therefore, first, which ZC (sequence root) sequence and PN (sequence seed) sequence was used is posted.

As shown in FIG. 14, the received discrete-time signal r (n) is supplied to the delay unit 1402 and the multiplication unit 1408, and is frequency-shifted corresponding to the frequency adjustment ^ej2πfT of the tone generation unit 1401. The output of the multiplier 1408 is supplied to two further delay units 1404 and 1406. The delay units 1404 and 1406 serve to delay the received signal by a number of samples equal to the number of A, A_B, and B portions of the frame synchronization OFDM symbol. The output of each delay unit is passed to further multiplication units 1410, 1412, and 1414, multiplied by the complex conjugate of the received discrete time signal r (n), and supplied to the moving average filters 1416, 1418, and 1420. This forms a correlation with the received signal according to delays A, A + B, and B. The output of moving average filter 1416 is delayed by delay element 1422 and the output of moving average filters 1418 and 1420 are upscaled by scaling elements 1424 and 1426, respectively. The outputs of the two scaling elements 1424 and 1426 are summed by the adder 1428. The output of the adder is then multiplied by the output of the delay element 1422 by a multiplier 1430 to generate a peak combined sample. The peak combined sample is generated by correlating each section C, A, and B of the received signal with a respective copy to identify the peak at which the FFT trigger point is detected at output 1432. Accordingly, the FFO supplied by the output 1434 is determined by the phase of the peak.

The used (ZC * PN) sequence is mapped to the subcarrier of the frame synchronization OFDM symbol. In the case of ATSC 3.0, the usage sequence is formed by the following multiplication.
Multiply the ZC sequence by root q = 137,
Multiply the PN sequence by one of the generator seeds in Table 2 below.

Other PN sequence seeds and other possible generator polynomials can be defined and used. Therefore, in the case of ATSC 3.0, there are 8 (ZC * PN) sequences that the transmission device may be able to use. In embodiments of the present technology, all eight sequences are pre-generated and stored at the receiving device. When trying to detect which of the eight sequences is used, the receiving apparatus can sequentially correlate the stored sequences with the FFT result of the A portion of the frame synchronization OFDM symbol. The sequence that yields the maximum peak correlation is the (ZC * PN) sequence used in the transmitter. The frequency offset is the relative bin position of the peak correlation from −F _max to F _max . Where F _max is the maximum target integer frequency offset in the FFT bin.

A flowchart of this procedure is shown in FIG. R ₁ (k) is the FFT of the frame-synchronized OFDM symbol, and C _i (k) is the i-th (ZC * PN) sequence. When the integer frequency offset and the (ZC * PN) sequence are detected, the receiving apparatus can proceed to decode the first signaling OFDM symbol after correcting the frequency offset.

The flowchart shown in FIG. 15 may be summarized as follows.
Start: At the start of processing, the received symbols are in the frequency domain, as shown in FIG. In embodiments, the symbol spectrum may be derived from an FFT of spectral output components greater than 2048p and oversampled.
S1501: At the start of the loop, the variable exponent of the reference signature sequence is initialized to i = 1.
S1502: Thereby, a cyclic correlation is performed between the received frequency domain OFDM symbol and the i-th signature sequence.
S1504 and S1506: If the reference signature sequence i is the same as that used in the transmitter, a significant peak value is detected in the output of the cross-correlation within the IFO. If no significant peak value is detected, processing proceeds to step S1508, where the variable index i of the reference signature sequence is increased and cross-correlation is attempted in the next reference signature sequence. Reference signature sequence candidates may be pre-stored in the receiver along with an index based on a combination of Zadoff-Chu root and PN generator seed used to generate a specific sequence.
S1510: If no significant cross correlation peak is detected, the current value i is an index of the desired reference signature sequence. When the spectrum is oversampled, the relative position of the peaks in the cross-correlation output is used to determine the integer frequency offset (IFO) and the fine frequency offset (FFO).
In stopping, the process ends.

Detection signaling of the first signaling data is transmitted by each first signaling OFDM symbol. The signaling parameters are encoded as a relative cyclic shift by the A part of the first signaling OFDM symbol. The relative cyclic shift is differentially encoded from symbol to symbol. In one example, the decoding process can detect a cyclic shift in a given symbol, which can then be differentially decoded with the cyclic shift of the previous symbol. In one example, the differential cyclic shift is determined as part of the decoding process itself. This is advantageous in that it avoids fairly computationally intensive and explicit channel estimation and correction.

R _n (k), H _n (k), P _n (k), and Z _n (k) are respectively represented as a received spectrum sequence, a channel transfer function, a used PN sequence, and a used ZC sequence for the nth symbol. To do. However, k is a subcarrier index. Also, let M _{n−1 be} an absolute cyclic shift at symbol n−1. On the other hand, let m be the incremental cyclic shift for symbol n−1 that encodes the signaling parameter transmitted by symbol n. Then, for the first signaling OFDM symbols n−1 and n, the following Equation 16 is assumed for a given frame.

That is, when the same ZC sequence is used for the frame-synchronized OFDM symbol and all the first preamble symbols of a given frame, and the noise of symbol n is designated as N _n (k), the following equation 17 is obtained. be able to.

It is assumed that n−1 = 0 and M _n−1 = 0, that is, there is no cyclic shift in the frame synchronization OFDM symbol of the frame. Decoding algorithm involves R n _(k) of divided by R _{n-1 (k),} determining the phase slope of the residual signal representing a cyclic shift of the m samples between two symbols. Therefore, it can be calculated as in the following Expression 18.

If the period of each frame synchronization OFDM symbol or the first preamble symbol is short, given the center frequency f ₀ and the relative receiving unit velocity v = c / f o _(However, c is speed of light) will of two consecutive symbols In between, it is reasonable to assume that the channel remains substantially constant. That is, the following Expression 19 is established.

As an example, for f ₀ = 690 MHz, which is the highest UHF band used for television, for the channel to change significantly between symbols, v needs to exceed about 1564 km / h.

In the above formula, since noise increases by multiplication, analysis becomes difficult and performance deteriorates. Nevertheless, the amplitude of the component result of the above equation is not particularly important since the relative cyclic shift that is desired to be decoded is within the phase gradient. Therefore, division by R _n−1 (k) can be changed to multiplication by its conjugate. This avoids cumbersome calculations and adds all the noise to the main phase signal. As far as the phase gradient is concerned, the result of division is equal to the result of multiplication by conjugate.

The second and third terms on the right side are modulation noise. On the other hand, since _Pn and _Pn-1 are positive and negative series, the last term is simply white noise. Since all noise increases with addition, the coupling index of these terms depends on the SNR of the received signal. Therefore, at a reasonable level of SNR, the resulting argument or phase trajectory is expected to be dominated by the first term on the right side. Thus, by detecting the resulting phase gradient, the relative cyclic shift m between the two symbols can be detected. Further, since the following Expression 22 holds, the cyclic shift can be detected by executing IFFT on the result and acquiring the sample position of the peak amplitude.

This algorithm is shown in FIG. According to the receiving apparatus shown in FIG. 16, the signal down-converted by the RF tuner 52 is received, and all the prefixes and postfixes are removed from the received signal after passing through the guard interval removing unit 56. The received signal is supplied to two branches. In the first branch, the received signal is delayed by a number of samples equal to the effective portion of the OFDM symbol by the delay unit 1601 so that the previous received spectrum sequence R _n−1 is transformed by the first FFT unit 1604. The The received signal is supplied via the second branch so that each received symbol is also converted by the second FFT unit 1602. Here, the conjugate 1606 of the output of the first FFT unit 1604 is multiplied by the multiplier 1608 by the output of the second FFT unit 1602. The result of the multiplication unit 1608 is then divided by the division unit 1610 into a plurality of PN sequences used for the current and previous symbols 1620 and supplied to the IFFT unit 1612. The signal that has passed through the IFFT unit 1612 and has undergone IFFT conversion is input to the peak detection unit 1614 and subtracted by the subtraction unit 1618 from the spectrum output component of 2048p.

Further processing of the peak position at the output of the peak detector, i.e., subtraction from 2048p _{is, R n-1} (k) of the case divided by _R n (k), can be avoided. In this case, using the conjugate instead of the division, the related expression is as shown in Expression 23 below.

  This technique is shown in FIG.

Since FIG. 17 is substantially the same as FIG. 16, only the differences will be described. In contrast to FIG. 16, the receiving device shown in FIG. 17 forms a conjugate of the currently received spectral sequence R _n . The spectrum sequence R _n is conjugated by the conjugate unit 1606, and is multiplied by the output of the spectrum sequence R _n−1 received before the FFT conversion by the multiplication unit 1608. The result of the multiplication unit 1608 is then divided by the division unit 1610 by a plurality of PN sequences used for the current and previous symbols 1720. Subtraction from 2048p is not necessary here. Therefore, the final output is received from the peak detector 1614.

  As shown in the examples of FIGS. 16 and 17, according to embodiments of the present technology, by detecting a cyclic shift of a signature sequence transmitted by a frequency-synchronized OFDM symbol and one first signaling OFDM symbol, A configuration for estimating first signaling data is provided. As illustrated in the example of FIG. 16, the FFT units 1602 and 1604 continuously convert the time lengths of the effective portions of the frequency synchronization OFDM symbol and the one or more first signaling OFDM symbols to the frequency domain. Configured. It will be appreciated that in other examples, a single FFT unit can be used instead of the two FFT units 1602 and 1604 for sequential operation. A multiplier 1608 receives each frequency domain sample of the current first signaling OFDM symbol and one or more first signaling immediately preceding one of the frame-synchronized OFDM symbols or the current first signaling OFDM symbol. Each sample is multiplied by the conjugate generated by the conjugate portion 1606 of one corresponding sample of the OFDM symbol to generate an intermediate sample for each subcarrier sample. The IFFT unit 1612 is configured to convert the intermediate samples obtained from the current first OFDM symbol to the time domain. A cyclic shift detector formed from the peak detector 1614 detects a cyclic shift of a signature sequence existing in each of one or more first signaling OFDM symbols from the peak of the intermediate sample converted to the time domain. Is configured to estimate first signaling data transmitted by each of the one or more first signaling OFDM symbols.

  Therefore, according to embodiments of the present technology, the receiving apparatus is configured to detect the first signaling data by detecting a relative cyclic shift between the frequency-synchronized OFDM symbol and the first signaling OFDM symbol. can do. Thereby, only addition noise exists in the detection process. Therefore, since the signaling data can be accurately estimated by detecting the cyclic shift of the signature sequence with a lower signal-to-noise ratio, the conjugate multiplication as shown in FIGS. 16 and 17 provides an advantage.

  FIG. 18 shows the block error rate versus symbol-to-noise ratio showing the performance difference between the method using conjugate multiplication as shown in FIGS. 16 and 17 and the frequency domain decoding algorithm using division according to an embodiment of the present technology. It is a graph.

  The plot is for an additive white Gaussian noise (AWGN) channel, and the conjugate multiplication algorithm as employed in the embodiments of the present technology has a point in SNR compared to that using actual division. It is clear that it is very good. This comparison becomes more prominent when there is multipath.

  For narrowband reception, the receiver tunes only for the relevant segment. This is shown in the representation of the signal transmitted in the structure by the transmitting device according to an embodiment of the present technology in FIG. FIG. 19 is a plot of frequency versus signal power of a frequency-divided OFDM symbol used to transmit the second signaling and payload data by the exemplary receiver shown in FIG. 20 when γ = 7. Indicates. Since the receiving apparatus shown in FIG. 20 corresponds to the example shown in FIG. 16, only the differences between FIG. 16 and FIG. 19 will be described. It will be appreciated that the exemplary narrowband receiver can also be implemented by making corresponding changes to the example shown in FIG.

In the example of the narrowband receiver shown in FIG. 20, the radio frequency detector / tuner 52 and the receiver only receive signals within the narrowband frequency Seg3 of FIG. 19, so that the received signal can be sampled at a lower rate. it can. Therefore, the input sampling rate of the receiving apparatus can be reduced by the coefficient γ. Similarly, for the example shown in FIGS. 16 and 17, the following adjustments are made to the exemplary receiving device shown in FIG.
The delay unit 1601 at the input is reduced to N _u / γ.
In response, the sizes of the FFT units 1602 and 1604 are reduced by N _u / γ.

Since the signal is sampled at a lower rate than the full band radio frequency transmission bandwidth signal, the length of each CAB region of the time domain symbol is reduced by / γ. In response, the length of all delay and moving average filters in FIG. 14 will also decrease by a factor γ. The scaling unit 1622 also divides (or multiplies) the section of the PN sequence by P _n * P _n−1 using samples from the received narrowband signal generated as an intermediate result at the output of the multiplication unit 1608. Configured.

When detecting the relative cyclic shift, all the related subcarriers as described above are processed using either method shown in FIG. 16 or FIG. Before performing the final IFFT, the segment of the related subcarrier obtained by dividing by P _n * P _n−1 from the scaling unit 1622 (or multiplying by − because both are positive and negative) is sent to the IFFT unit 1612. Supplied, each subcarrier is in the correct position and all other subcarriers are set to zero. That is, the upsampling unit 2001 is configured to add zero samples to the frequency domain samples provided at the output of the division unit 1610. After that, the IFFT size applied by the IFFT unit 1612 is applied as if the entire band receiving device is used. The output then provides a phase gradient in a manner corresponding to the cases of FIGS. The peak height of the output of IFFT unit 1612 is affected by the absolute number of subcarriers in the processing segment. This means that when the FFT size of the first signaling OFDM symbol is small, the peak is greatly reduced, and therefore, the possibility that a block error will occur is higher than when the FFT size is large.

  Thus, according to embodiments of the present technology, a radio frequency demodulation circuit of a receiving device is applied to one of the frequency segments of one or more second signaling OFDM symbols and one or more payload OFDM symbols. It is configured to detect and recover radio signals within the corresponding bandwidth. The inverse Fourier transform is configured to transform intermediate samples generated by multiplying the frequency domain samples of the current first signaling OFDM symbol by the conjugate of the previous frequency-synchronized OFDM symbol, where each sample Corresponds to a complex sample of each detected subcarrier of a segment of an OFDM symbol). The intermediate samples are transformed to the time domain and indicate the result of the current symbol of the one or more first OFDM symbols, but are upsampled according to the bandwidth corresponding to the radio frequency transmission bandwidth. Thereby, the cyclic shift detection unit can detect the cyclic shift of the signature sequence from the time domain intermediate samples generated for the intermediate samples whose bandwidth is increased to the radio frequency transmission bandwidth.

  Thus, according to an example, the upscaling unit 2001 is configured to receive an intermediate sample in the frequency domain and add a zero sample to the intermediate sample. The intermediate sample corresponds to an equivalent in the frequency domain of the radio frequency transmission bandwidth.

  As can be understood from the above description, according to embodiments of the present technology, it is possible to provide a configuration that enables both time division multiplexing and frequency division multiplexing of services in the same radio frequency channel. it can. This is achieved according to embodiments of the present technology, employing the proposed frame structure shown in FIG. Thereby, the capacity of the mobile service can be increased.

The following numbered paragraphs define further exemplary aspects and features of the technology.
Paragraph 1
A transmitter that transmits payload data using OFDM symbols that are orthogonal frequency division multiplexed,
A frame builder configured to receive the payload data transmitted from a plurality of different channels and frame the payload data received from each channel for a plurality of time frames into a plurality of transmission payload data frames;
For each of the plurality of payload data frames, a frame synchronization OFDM symbol, one or more first signaling OFDM symbols, one or more second signaling OFDM symbols are generated, and the payload data received from each of the channels A modulator configured to modulate one or more payload OFDM symbols;
A transmitter that transmits the plurality of payload data frames as a plurality of transmission frames;
Each of the plurality of transmission frames includes one or more payload OFDM symbols, a frame synchronization OFDM symbol for the one or more payload OFDM symbols, followed by the one or more first signaling. Preceded by an OFDM symbol followed by the one or more second signaling OFDM symbols;
The frame-synchronized OFDM symbol and the one or more first signaling OFDM symbols are transmitted with a bandwidth equal to a radio frequency transmission bandwidth, and the one or more second signaling OFDM symbols and the one or more A plurality of payload OFDM symbols are transmitted in the radio frequency transmission bandwidth, and the one or more second signaling OFDM symbols and the one or more payload OFDM symbols are each frequency-divided into a plurality of frequencies. Providing a segment, wherein each of the plurality of frequency segments transmits payload data from a different channel, and the one or more second signaling OFDM symbols in each frequency segment are the one or more payload OFDM symbols. Multiple from symbol to above Transmitting one instance of a plurality of instances of physical layer signaling for detecting and recovering the payload data transmitted by a frequency segment for each channel, wherein the one or more first signaling OFDM symbols are: A transmitting apparatus for transmitting first signaling data for detecting the second signaling OFDM symbol.
Paragraph 2
The transmitting device according to paragraph 1, further comprising:
Modulating the frame-synchronized OFDM symbol with a signature sequence, and using one or more first signaling OFDM symbols in the time domain cyclically shifted with respect to the one or more first signaling OFDM symbols and a preceding symbol A signature sequence combination unit configured to modulate,
The cyclic shift of one or more first signaling OFDM symbols in the time domain represents the first signaling data transmitted in the one or more first signaling OFDM symbols.
Paragraph 3
The transmission device according to paragraph 1 or 2, wherein
The first signaling data includes an indication of the number of frequency segments.
Paragraph 4
The transmission device according to any one of paragraphs 1, 2, or 3,
The first signaling data includes an indication of an emergency situation.
Paragraph 5
The transmission device according to any one of paragraphs 1, 2, 3, or 4,
The first signaling data includes an indication of a Fourier transform size and a guard interval used for the one or more second signaling OFDM symbols and the one or more payload OFDM symbols.
Paragraph 6
The transmission device according to any one of paragraphs 1 to 5,
The modulation unit combined with the transmission apparatus includes a first part C composed of a plurality of samples of an effective part of the frame-synchronized OFDM symbol, and a part A including the effective part of the frame-synchronized OFDM symbol. Configured to form the frame-synchronized OFDM symbol according to one time domain structure;
Transmitting apparatus wherein part B of the first part is copied to form a postamble of the frame-synchronized OFDM symbol.
Paragraph 7
The transmission device according to any one of paragraphs 1 to 6,
The modulation unit combined with the transmission apparatus includes a first part B composed of a plurality of samples of an effective part of the first signaling OFDM symbol, and a part A including the effective part of the first signaling OFDM symbol. And a portion C including an effective portion of the first signaling OFDM symbol, and configured to form the one or more first signaling OFDM symbols,
The part A is copied to form a second part of the first signaling OFDM symbol.
Paragraph 8
The transmission device according to paragraph 1, wherein
The signature sequence includes a combination of a Zadoff-chu sequence and a pseudo random noise sequence.
Paragraph 9
A transmission method for transmitting payload data using OFDM symbols that are orthogonal frequency division multiplexed,
Receive the payload data sent from multiple different channels,
Payload data received from each channel for a plurality of time frames is framed into a plurality of payload data frames for transmission,
Generating a frame-synchronized OFDM symbol, one or more first signaling OFDM symbols, one or more second signaling OFDM symbols for each of the plurality of payload data frames;
Modulate one or more payload OFDM symbols with payload data received from each of the channels,
Sending the plurality of payload data frames as a plurality of transmission frames,
Each of the plurality of transmission frames includes one or more payload OFDM symbols, a frame synchronization OFDM symbol for the one or more payload OFDM symbols, followed by the one or more first signaling. Preceded by an OFDM symbol followed by the one or more second signaling OFDM symbols;
The frame-synchronized OFDM symbol and the one or more first signaling OFDM symbols are transmitted with a bandwidth equal to a radio frequency transmission bandwidth, and the one or more second signaling OFDM symbols and the one or more A plurality of payload OFDM symbols are transmitted in the radio frequency transmission bandwidth, and the one or more second signaling OFDM symbols and the one or more payload OFDM symbols are each frequency-divided into a plurality of frequencies. Providing a segment, wherein each of the plurality of frequency segments transmits payload data from a different channel, and the one or more second signaling OFDM symbols in each frequency segment are the one or more payload OFDM symbols. Multiple from symbol to above Transmitting one instance of a plurality of instances of physical layer signaling for detecting and recovering the payload data transmitted by a frequency segment for each channel, wherein the one or more first signaling OFDM symbols are: A transmission method for transmitting first signaling data for detecting the second signaling OFDM symbol.
Paragraph 10
The transmission method according to paragraph 9, further comprising:
Modulate the frame-synchronized OFDM symbol with a signature sequence,
Modulating the one or more first signaling OFDM symbols in the time domain cyclically shifted with respect to the one or more first signaling OFDM symbols and the preceding symbol;
The cyclic shift of one or more first signaling OFDM symbols in the time domain represents the first signaling data transmitted in the one or more first signaling OFDM symbols.
Paragraph 11
The transmission method according to paragraph 9 or 10, wherein
The first signaling data includes an indication of the number of frequency segments.
Paragraph 12
The transmission method according to any one of paragraphs 9, 10, or 11,
The first signaling data includes an indication of an emergency situation.
Paragraph 13
The transmission method according to any one of paragraphs 9, 10, 11, or 12,
The first signaling data includes an indication of a Fourier transform size and a guard interval used for the one or more second signaling OFDM symbols and the one or more payload OFDM symbols.
Paragraph 14
The transmission method according to any one of paragraphs 9 to 13, further comprising:
The frame-synchronized OFDM symbol according to a first time-domain structure comprising a first part C comprising a plurality of samples of the effective part of the frame-synchronized OFDM symbol and a part A containing the effective part of the frame-synchronized OFDM symbol. Forming,
Transmission method of part B of the first part being copied to form a postamble of the frame-synchronized OFDM symbol.
Paragraph 15
15. The transmission method according to any one of paragraphs 9 to 14, further comprising:
A first part B comprising a plurality of samples of an effective part of the first signaling OFDM symbol; a part A including the effective part of the first signaling OFDM symbol; and an effective part of the first signaling OFDM symbol. Forming one or more first signaling OFDM symbols with part C comprising:
The part A is copied to form a second part of the first signaling OFDM symbol.
Paragraph 16
The transmission method according to paragraph 9, wherein
The signature sequence includes a combination of a Zadoff-chu sequence and a pseudo random noise sequence.
Paragraph 17
A receiving device for detecting and restoring payload data from a received signal,
Configured to detect and restore the received signal formed and transmitted by a transmitting apparatus that transmits the payload as one or more frames among a plurality of transmission frames as orthogonal frequency division multiplexing (OFDM) symbols from a plurality of different channels And the plurality of transmission frames each include a frame-synchronized OFDM symbol, one or more first signaling OFDM symbols, and one or more second OFDM symbols. Followed by one or more payload OFDM symbols, wherein the one or more payload OFDM symbols transmit payload data for each of the plurality of different channels from one time frame of the plurality of time frames. The frame-synchronized OFDM symbol and the above The one or more first signaling OFDM symbols are transmitted with a bandwidth equal to a radio frequency transmission bandwidth, and the one or more second signaling OFDM symbols and the one or more payload OFDM symbols are: The one or more second signaling OFDM symbols and the one or more payload OFDM symbols transmitted in the radio frequency transmission bandwidth are each frequency-divided to provide a plurality of frequency segments, Each of the frequency segments is a physical for detecting and restoring for each channel the payload data from different channels and the payload data transmitted by the plurality of frequency segments from the corresponding segment of the one or more payload OFDM symbols. Layer signaling Radio frequency demodulation providing one of a number of instances, wherein the one or more first signaling OFDM symbols carry first signaling data for detecting the second signaling OFDM symbol Circuit,
A detection circuit configured to detect, from the frequency synchronization OFDM symbol, a synchronization timing for converting a time length of an effective portion of the one or more first signaling OFDM symbols of the payload OFDM symbol into a frequency domain;
A forward Fourier transform circuit configured to transform the time length of the one or more first signaling OFDM symbols or the payload OFDM symbols from the time domain to the frequency domain according to the identified synchronization timing; ,
Reconstructing the first signaling data from the first signaling OFDM symbol and using the first signaling data from the one or more second signaling OFDM symbols from one of the frequency segments Demodulation configured to detect and recover the physical layer signaling data and recover the payload data for each time frame from one of the frequency segments of the one or more payload OFDM symbols And a receiving device.
Various further aspects and features of the present technology are defined in the appended claims, and the features of the dependent claims may vary from the features of the independent claims other than the specific combinations recited for the dependent claims. Can be combined. Modifications may be made to the above-described embodiment without departing from the scope of the present technology. For example, the processing elements of the embodiments may be implemented with hardware, software, and digital or analog circuitry. Moreover, those skilled in the art will appreciate that certain features may be described as being associated with a particular embodiment, or various features of the above-described embodiments may be combined in accordance with the present technology.
[1] ATSC standard: A / 321, system discovery and signaling (ATSC Standard: A / 321, System Discovery and Signaling Doc. A / 321: 2016): March 23, 2016 [2] ATSC candidate standard: system discovery And Signaling (ATSC Candidate Standard: System Discovery and Signaling (Doc. A / 321 Part 1)), Advanced Television Systems Committee, July 15, 2015

Claims (17)

A transmitter that transmits payload data using OFDM symbols that are orthogonal frequency division multiplexed,
A frame builder configured to receive the payload data transmitted from a plurality of different channels and frame the payload data received from each channel for a plurality of time frames into a plurality of payload data frames for transmission;
For each of the plurality of payload data frames, a frame synchronization OFDM symbol, one or more first signaling OFDM symbols, one or more second signaling OFDM symbols are generated, and payload data received from each channel A modulator configured to modulate one or more payload OFDM symbols;
Comprising a transmitter for transmitting the plurality of payload data frames as a plurality of transmission frames;
Each of the plurality of transmission frames includes one or more payload OFDM symbols, a frame synchronization OFDM symbol for the one or more payload OFDM symbols, followed by the one or more first signalings. Preceded by an OFDM symbol followed by the one or more second signaling OFDM symbols;
The frame-synchronized OFDM symbol and the one or more first signaling OFDM symbols are transmitted with a bandwidth equal to a radio frequency transmission bandwidth, and the one or more second signaling OFDM symbols and the one or more A plurality of payload OFDM symbols are transmitted in the radio frequency transmission bandwidth, and the one or more second signaling OFDM symbols and the one or more payload OFDM symbols are each frequency-divided into a plurality of frequencies. Providing a segment, wherein each of the plurality of frequency segments transmits payload data from a different channel, and the one or more second signaling OFDM symbols in each frequency segment are the one or more payload OFDM symbols. Multiple from symbol Transmitting one of a plurality of instances of physical layer signaling for detecting and recovering the payload data transmitted by a frequency segment for each channel, wherein the one or more first signaling OFDM symbols are: A transmission apparatus for transmitting first signaling data for detecting the second signaling OFDM symbol. The transmission device according to claim 1, further comprising:
Modulating the frame-synchronized OFDM symbol with a signature sequence, and using one or more first signaling OFDM symbols in the time domain cyclically shifted with respect to the one or more first signaling OFDM symbols and a preceding symbol Comprising a signature sequence combination unit configured to modulate,
A cyclic shift of one or more first signaling OFDM symbols in the time domain represents the first signaling data transmitted in the one or more first signaling OFDM symbols. The transmission device according to claim 1 or 2,
The first signaling data includes an indication of the number of frequency segments.
The transmission device according to claim 1, 2, or 3,
The first signaling data includes an indication of an emergency situation. The transmission device according to claim 1, 2, 3, or 4,
The first signaling data includes an indication of a Fourier transform size and a guard interval used for the one or more second signaling OFDM symbols and the one or more payload OFDM symbols. The transmission device according to any one of claims 1 to 5,
The modulation unit combined with the transmission apparatus includes a first part C composed of a plurality of samples of an effective part of the frame-synchronized OFDM symbol, and a part A including the effective part of the frame-synchronized OFDM symbol. Configured to form the frame-synchronized OFDM symbol according to a time domain structure of 1;
The first part part B is copied to form a postamble of the frame-synchronized OFDM symbol. The transmission device according to any one of claims 1 to 6,
The modulation unit combined with the transmitter comprises a first part B comprising a plurality of samples of an effective part of the first signaling OFDM symbol and a part A including the effective part of the first signaling OFDM symbol And the portion C including an effective portion of the first signaling OFDM symbol, and configured to form the one or more first signaling OFDM symbols,
The part A is copied to form a second part of the first signaling OFDM symbol. The transmission device according to claim 1,
The signature sequence includes a combination of a Zadoff-chu sequence and a pseudo-random noise sequence. A transmission method for transmitting payload data using OFDM symbols that are orthogonal frequency division multiplexed,
Receiving the payload data transmitted from a plurality of different channels;
Payload data received from each channel for a plurality of time frames into a plurality of payload data frames for transmission,
Generating a frame-synchronized OFDM symbol, one or more first signaling OFDM symbols, one or more second signaling OFDM symbols for each of the plurality of payload data frames;
Modulating one or more payload OFDM symbols with payload data received from each channel;
Transmitting the plurality of payload data frames as a plurality of transmission frames;
Each of the plurality of transmission frames includes one or more payload OFDM symbols, a frame synchronization OFDM symbol for the one or more payload OFDM symbols, followed by the one or more first signalings. Preceded by an OFDM symbol followed by the one or more second signaling OFDM symbols;
The frame-synchronized OFDM symbol and the one or more first signaling OFDM symbols are transmitted with a bandwidth equal to a radio frequency transmission bandwidth, and the one or more second signaling OFDM symbols and the one or more A plurality of payload OFDM symbols are transmitted in the radio frequency transmission bandwidth, and the one or more second signaling OFDM symbols and the one or more payload OFDM symbols are each frequency-divided into a plurality of frequencies. Providing a segment, wherein each of the plurality of frequency segments transmits payload data from a different channel, and the one or more second signaling OFDM symbols in each frequency segment are the one or more payload OFDM symbols. Multiple from symbol Transmitting one of a plurality of instances of physical layer signaling for detecting and recovering the payload data transmitted by a frequency segment for each channel, wherein the one or more first signaling OFDM symbols are: A transmission method for transmitting first signaling data for detecting the second signaling OFDM symbol. The transmission method according to claim 9, further comprising:
Modulating the frame-synchronized OFDM symbol with a signature sequence;
Modulating one or more first signaling OFDM symbols in the time domain cyclically shifted with respect to the one or more first signaling OFDM symbols and a preceding symbol;
The cyclic shift of one or more first signaling OFDM symbols in the time domain represents the first signaling data transmitted in the one or more first signaling OFDM symbols. The transmission method according to claim 9 or 10, wherein
The first signaling data includes an indication of the number of frequency segments. The transmission method according to claim 9, 10, or 11,
The first signaling data includes an indication of an emergency situation. The transmission method according to claim 9, 10, 11, or 12,
The first signaling data includes an indication of a Fourier transform size and a guard interval used for the one or more second signaling OFDM symbols and the one or more payload OFDM symbols. The transmission method according to any one of claims 9 to 13, further comprising:
The frame-synchronized OFDM symbol according to a first time-domain structure comprising a first part C comprising a plurality of samples of the effective part of the frame-synchronized OFDM symbol and a part A comprising the effective part of the frame-synchronized OFDM symbol Forming,
Transmission method of part B of the first part being copied to form a postamble of the frame-synchronous OFDM symbol. The transmission method according to any one of claims 9 to 14, further comprising:
A first part B comprising a plurality of samples of an effective part of the first signaling OFDM symbol; a part A including the effective part of the first signaling OFDM symbol; and an effective part of the first signaling OFDM symbol Forming said one or more first signaling OFDM symbols with part C comprising:
The part A is copied to form a second part of the first signaling OFDM symbol. The transmission method according to claim 9, comprising:
The signature sequence includes a combination of a Zadoff-chu sequence and a pseudo-random noise sequence. A receiving device for detecting and restoring payload data from a received signal,
A configuration for detecting and restoring the received signal formed and transmitted by a transmitting apparatus that transmits the payload as one or more frames among a plurality of transmission frames as orthogonal frequency division multiplexing (OFDM) symbols from a plurality of different channels. Radio frequency demodulation circuit, wherein each of the plurality of transmission frames includes a frame-synchronized OFDM symbol, one or more first signaling OFDM symbols, and one or more second OFDM symbols. Followed by one or more payload OFDM symbols, wherein the one or more payload OFDM symbols transmit payload data for each of the different channels from one time frame of the plurality of time frames. The frame-synchronized OFDM symbol and the previous One or more first signaling OFDM symbols are transmitted with a bandwidth equal to a radio frequency transmission bandwidth, and the one or more second signaling OFDM symbols and the one or more payload OFDM symbols are: The one or more second signaling OFDM symbols and the one or more payload OFDM symbols transmitted in the radio frequency transmission bandwidth are each frequency-divided to provide a plurality of frequency segments; Each frequency segment is a physical for detecting and recovering for each channel payload data from different channels and the payload data transmitted by the plurality of frequency segments from corresponding segments of the one or more payload OFDM symbols. Layer signaling Radio frequency demodulation providing one instance of a number of instances, wherein the one or more first signaling OFDM symbols carry first signaling data for detecting the second signaling OFDM symbol Circuit,
A detection circuit configured to detect, from the frequency synchronization OFDM symbol, a synchronization timing for converting a time length of an effective portion of the one or more first signaling OFDM symbols of the payload OFDM symbol into a frequency domain;
A forward Fourier transform circuit configured to transform the time length of the one or more first signaling OFDM symbols or the payload OFDM symbols from the time domain to the frequency domain according to the specified synchronization timing; ,
Reconstructing the first signaling data from the first signaling OFDM symbol and using the first signaling data, one segment of the frequency segment of the one or more second signaling OFDM symbols Configured to detect and recover the physical layer signaling data from and to recover the payload data for each time frame from one of the frequency segments of the one or more payload OFDM symbols. A receiving device comprising a demodulation circuit.