JP7284653B2 - transmitter and receiver - Google Patents

Description

Application of Article 30, Paragraph 2 of the Patent Law 2018 Institute of Image Information and Television Engineers Annual Conference Lecture Proceedings, 33D-4 Publication date: August 15, 2018

The present invention relates to a transmitting device and a receiving device in a digital broadcasting system that divides the frequency band of a broadcasting channel into a plurality of segments and uses them.

"ISDB-T (Integrated Services Digital Broadcasting-Terrestrial)" is used as the current terrestrial digital broadcasting transmission system in Japan (see, for example, Non-Patent Document 1). With ISDB-T, the frequency band of one broadcast channel is divided into 13 segments, and the modulation method and error correction method can be changed for each segment. can be used for various purposes.

Note that one segment is composed of a plurality of carriers. A group of segments to which the same modulation scheme, error correction scheme, etc. are applied is called a hierarchy, and transmission is possible in three hierarchies (A hierarchy, B hierarchy, and C hierarchy) at maximum. In general, the central one-segment band (partial reception band) of the 13 segments is allocated for mobile reception, and the remaining 12-segment bands (non-partial reception band) are allocated for stationary reception.

On the other hand, a next-generation terrestrial digital broadcasting transmission system to replace the current terrestrial digital broadcasting transmission system is being studied. In the next-generation terrestrial digital broadcasting transmission system, as in the current terrestrial digital broadcasting transmission system, mobile reception data (A layer data) and fixed reception data (B layer data) can be transmitted in one broadcasting channel. It is assumed that one broadcast channel is divided into, for example, 35 segments, and a method of transmitting data for mobile reception (layer A data) using the central 9-segment band as a partial reception band is being studied. In this case, the remaining 26 segments are the non-partial reception band.

When performing partial reception in the next-generation terrestrial digital broadcasting transmission system, it is assumed that the number of segments in layer A can be selected from 1 to 9 segments. Also, in the case of two-layer transmission, if the number of segments in the A layer is less than nine, the remaining segments in the partial reception band are assigned to the B layer. For example, if the number of segments in the A layer is 3, the partial reception band includes 6 segments of the B layer. In such a case, the A layer and the B layer coexist within the partial reception band.

In Patent Document 1, in order to realize appropriate frequency interleaving under such a premise, as frequency interleaving within the partial reception band, inter-segment interleaving and segment-by-segment interleaving are applied to SPs of the A layer and B layer ( It is described that it is used properly according to the Scattered Pilot) pattern or the like. Specifically, inter-segment interleaving is applied when the SP patterns of layer A and layer B in the partial reception band are the same, or when only layer A is included in the partial reception band. Segment-by-segment interleaving is applied when the SP patterns of layer A and layer B within the partial reception band are different.

When the A layer and the B layer coexist within the partial reception band, the intersegment interleaving interleaves all segments of the A layer and the B layer on a carrier-by-carrier basis. Therefore, even if the A layer has only one segment, for example, since the A layer carriers are dispersed within the 9 segments of the partial reception band, it is possible to obtain the effect of broadening the band to 9 segment bands. As a result, the effects of frequency selective fading, which is affected by distortion only in a specific frequency range, can be mitigated, and transmission characteristics can be improved.

On the other hand, segment unit interleaving interleaves the A layer and the B layer in units of segments according to an interleave table that defines the correspondence relationship between the segment numbers before interleaving and the segment numbers after interleaving. For this reason, if the A layer has only one segment, for example, only one fixed segment in the nine segments is used. That is, layer A continues to use the segment with the same segment number. Therefore, segment unit interleaving cannot obtain the effect of widening the band to 9 segments, and there is a problem that the effect of improving transmission characteristics is smaller than inter-segment interleaving.

In Non-Patent Document 2, when inter-layer segment unit interleaving is performed, by switching the interleave table for each symbol, even with inter-layer segment unit interleaving, the effect of widening the band to 9 segment bands is obtained, and transmission It is described that the characteristics are improved.

ARIB STD-B31 "Transmission system for digital terrestrial television broadcasting" Miyasaka et al., "A study on cyclic shift interleaving in provisional specifications for next-generation terrestrial broadcasting", 2018 Institute of Image Information and Television Engineers Annual Conference, 33D-4

JP 2018-88677 A

In ISDB-T, the SISO (Single Input Single Output) method using only horizontal polarization or vertical polarization is used. A polarized wave MIMO (Multiple Input Multiple Output) system that transmits different data sequences by simultaneously using the two systems is also under study.

However, although the technology described in Non-Patent Document 2 can improve the transmission characteristics in the SISO scheme, it does not take into account further improvement in the transmission characteristics in the MIMO transmission scheme.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a transmitting apparatus and a receiving apparatus that improve transmission characteristics when segment-based interleaving is performed in the MIMO transmission system.

A transmitting device according to a first aspect is a transmitting device used in a digital broadcasting system in which a frequency band of a broadcasting channel is divided into a plurality of segments. The transmission device includes two transmission units that transmit two data sequences using the MIMO transmission scheme. When performing frequency interleaving on a segment basis, each of the two transmission units switches the correspondence relationship between the segment number before interleaving and the segment number after interleaving at a switching cycle consisting of one or more symbols. Within the same switching cycle, the correspondence relationship used by one of the two transmission units and the correspondence relationship used by the other transmission unit of the two transmission units different from each other.

A receiving device according to a second aspect is a receiving device used in a digital broadcasting system in which a frequency band of a broadcasting channel is divided into a plurality of segments. The receiving device includes two receiving units for receiving two data sequences using the MIMO transmission system. When performing frequency deinterleaving in segment units, each of the two systems of receiving units switches the correspondence relationship between the segment number before deinterleaving and the segment number after deinterleaving at a switching cycle consisting of one or more symbols. . Within the same switching cycle, the correspondence relationship used by one of the two systems of reception units and the correspondence relationship used by the other system of the two systems of reception units different from each other.

Advantageous Effects of Invention According to the present invention, it is possible to provide a transmitting apparatus and a receiving apparatus that improve transmission characteristics when performing segment-by-segment interleaving in the MIMO transmission scheme.

FIG. 2 is a diagram showing a segment structure in a digital broadcasting system according to an embodiment in comparison with an ISDB-T segment structure; 1 is a diagram showing the configuration of a transmission device in a digital broadcasting system according to an embodiment; FIG. It is a figure which shows the structural example of the system separation part which concerns on embodiment. FIG. 4 is a diagram illustrating an example of inter-segment interleaving according to the embodiment; FIG. 4 is a diagram showing basic operation of segment-based interleaving according to the embodiment; FIG. 3 is a diagram showing configuration example 1 of an inter-layer interleaving unit of a 1-system transmitting unit and an inter-layer interleaving unit of a 2-system transmitting unit according to an embodiment; FIG. 4 is a diagram showing an example of an interleave table respectively held by a 1-system interleave table holding unit and a 2-system interleave table holding unit according to the embodiment; FIG. 10 is a diagram illustrating configuration example 2 of an inter-layer interleaving unit of a 1-system transmitting unit and an inter-layer interleaving unit of a 2-system transmitting unit according to the embodiment; FIG. 10 is a diagram showing an example of a basic interleave table and an interleave table after cyclic shift according to the embodiment; FIG. 10 is a diagram showing an example of an interleave table when offset shift is given to one system according to the embodiment; 1 is a diagram showing the configuration of a receiving device in a digital broadcasting system according to an embodiment; FIG. FIG. 4 is a diagram showing a configuration example 1 of an inter-layer deinterleaving unit of the system 1 receiving unit and an inter-layer deinterleaving unit of the system 2 receiving unit according to the embodiment; FIG. 10 is a diagram illustrating configuration example 2 of an inter-layer deinterleaving unit of the system 1 receiving unit and an inter-layer deinterleaving unit of the system 2 receiving unit according to the embodiment; It is a figure for demonstrating the effect of embodiment.

A digital broadcasting system according to the present embodiment will be described with reference to the drawings. In the description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. The digital broadcasting system according to this embodiment is a broadcasting system (digital terrestrial television broadcasting system) compatible with the next-generation digital terrestrial broadcasting transmission system.

(segment structure)
First, an example of the segment structure in the digital broadcasting system according to this embodiment will be described. FIG. 1 is a diagram showing the segment structure in the digital broadcasting system according to this embodiment in comparison with the segment structure of ISDB-T.

FIG. 1(a) shows the segment structure of ISDB-T, FIG. 1(b) shows the segment structure of the compatible mode of the next-generation digital terrestrial broadcasting transmission system, and FIG. The segment structure of the extension mode of the digital terrestrial broadcasting transmission system is shown.

In ISDB-T shown in FIG. 1(a), one broadcast channel is composed of 13 segments and has a bandwidth of 5.57 MHz. In one broadcasting channel of ISDB-T, one central segment is the partial reception band α, and 12 segments arranged on both sides of such a partial reception band are the non-partial reception band β.

As shown in FIG. 1(b), in the compatible mode of the next-generation digital terrestrial broadcasting transmission system, one broadcasting channel consists of 33 segments (seg) and an adjustment band (0.07 MHz). It has the same 5.57 MHz bandwidth as one broadcast channel of T. In the compatible mode segment structure, in one broadcast channel, the central 9 segments are the partial reception band α, and the 24 segments arranged on both sides of the partial reception band α are the non-partial reception band β. , and the adjustment band γ is arranged on both sides of the non-partial reception band β.

As shown in FIG. 1(c), in the normal mode of the next-generation terrestrial digital broadcasting transmission system, one broadcasting channel consists of 35 segments and has a bandwidth of 5.83 MHz. In the segment structure of the extension mode, in one broadcast channel, the central 9 segments are the partial reception band α, and the 26 segments arranged on both sides of such partial reception band α are the non-partial reception band β. .

(Transmitter)
Next, the configuration of the transmission device in the digital broadcasting system according to this embodiment will be described. FIG. 2 is a diagram showing the configuration of the transmission device 100 in the digital broadcasting system according to this embodiment.

As shown in FIG. 2, transmitting apparatus 100 transmits different data sequences according to a polarized MIMO scheme that simultaneously uses two systems of horizontal polarization and vertical polarization (hereinafter referred to as "system 1" and "system 2"). Send. However, the MIMO transmission is not limited to two systems, and a MIMO transmission system of three or more systems may be applied.

Also, transmitting apparatus 100 performs hierarchical transmission up to three layers in each of the two systems. Specifically, the transmitting device 100 according to the present embodiment can transmit layer A data, layer B data, and layer C data. For example, A layer data is broadcast data for mobile reception, and B layer data and C layer data are broadcast data for fixed reception.

Transmitting apparatus 100 has BICM section 101 , mapping section 102 , system separating section 103 , system 1 transmitting section 110 , and system 2 transmitting section 130 .

BICM section 101 performs error correction coding and bit interleaving on transmission data by BICM (Bit-Interleaved Coded Modulation), and outputs transmission data after error correction coding and bit interleaving to mapping section 102 .

Mapping section 102 maps the transmission data output from BICM section 101 to modulation symbols, and outputs the transmission data mapped to the modulation symbols to system separation section 103 .

System separating section 103 separates the transmission data output from mapping section 102 into 1-system and 2-system, outputs the 1-system data sequence to 1-system transmitting section 110, and transmits the 2-system data sequence to 2-system transmission. Output to unit 130 . FIG. 3 is a diagram showing a configuration example of the system separation unit 103. As shown in FIG. As shown in FIG. 3 , system separation section 103 has switch section SW that switches transmission data output from mapping section 102 to system 1 and system 2 symbol by symbol.

The 1-system transmission unit 110 and the 2-system transmission unit 130 correspond to 2-system transmission units that transmit 2-system data sequences using the MIMO transmission scheme. In this embodiment, the 1-system transmitter 110 corresponds to one of the horizontally polarized wave and the vertically polarized wave, and the 2-system transmitter 130 corresponds to the other of the horizontally polarized wave and the vertically polarized wave.

System 1 transmitting section 110 includes layer separation section 111, layer-specific time interleaving section 112 (112a, 112b, 112c), layer-specific intersegment interleaving section 113 (113a, 113b, 113c), and partial reception band division. section 114, inter-layer interleaving section 115 (115a, 115b) for each band, intra-segment interleaving section 116 (116a, 116b) for each band, band synthesis section 117, framing section 118, and IFFT section 119 , and a GI assigning unit 120 .

The layer separating unit 111 separates the system 1 data series output from the system separating unit 103 into layer A data, layer B data, and layer C data, outputs the layer A data to the time interleaving unit 112a, and outputs layer B data. is output to the time interleaver 112b, and the layer C data is output to the time interleaver 112c.

The hierarchical time interleaving section 112 (112a, 112b, 112c) time-interleaves each of the A-layer data, the B-layer data, and the C-layer data output from the layer separation section 111. Each layer data is output to the inter-segment interleaving unit 113 (113a, 113b, 113c) for each layer.

The inter-segment interleaving units 113 (113a, 113b, 113c) for each hierarchy add Intersegment interleaving (carrier-by-carrier interleaving) is performed on the data, and each hierarchical data after intersegment interleaving is output to partial reception band dividing section 114 . Specifically, the hierarchical inter-segment interleaving section 113 (113a, 113b, 113c) performs frequency interleaving on a carrier-by-carrier basis over all segments of the corresponding hierarchy.

FIG. 4 is a diagram showing an example of such intersegment interleaving. FIG. 4(a) shows the arrangement of carriers Si (i=0 to nz−1) before frequency interleaving, and FIG. 4(b) shows the arrangement of carriers Si (i=0 to nz−1) after frequency interleaving. Show the sequence. Here, n indicates the number of segments of each hierarchical data, and z indicates the number of carriers per segment. Note that z is determined based on the SP interval. For example, if the FFT size is 8k points, z can be 174, 192, 201; if the FFT size is 16k points, z can be 276, 348, 384, 402, 411. , and the FFT size is 32k points, z can be any of 552, 696, 768, 804, 822, 836, 838, 839. For example, when the number of segments n in layer A is 7 and z is 174, inter-segment interleaving section 113a performs frequency interleaving on a carrier-by-carrier basis over all segments 0 to n−1 constituting layer A. FIG. That is, the intersegment interleaving section 113a changes the arrangement of the carriers S ₀ to S ₁₂₁₇ on which the layer A data is mapped from the arrangement shown in FIG. 4(a) to the arrangement shown in FIG. 4(b).

The partial reception band division unit 114 divides the A-layer data, B-layer data, and C-layer data output from the inter-segment interleaving units 113 (113a, 113b, 113c) for each layer into a partial reception band and a non-partial reception band. The data in the partial reception band is output to inter-layer interleaving section 115a, and the data in the non-partial reception band is output to inter-layer interleaving section 115b.

For example, the partial reception band division unit 114 generates partial reception band data by allocating layer B data when there is space after allocating layer A data to the partial reception band α consisting of 9 segments, and generating partial reception band data. Non-partial reception band data is generated by assigning the rest of the B layer data and the C layer data to β. When the A-layer data consists of less than 9 segments, the partial reception band division unit 114 assigns the B-layer data to the partial reception band α in order from the lowest segment number, and divides the A-layer data and the B-layer data. A total of 9 segments of partial reception band data are generated. On the other hand, when the A-layer data consists of 9 segments, the partial reception band dividing section 114 treats only the A-layer data as partial reception band data, and treats the B-layer data and the C-layer data as non-partial reception band data.

Band-specific inter-hierarchy interleaving sections 115 (115a, 115b) perform frequency interleaving on each of the partial reception band data and the non-partial reception band data output from partial reception band division section 114, and divide the frequency-interleaved portion into The reception band data is output to intra-segment interleaving section 116a, and the non-partial reception band data after frequency interleaving is output to intra-segment interleaving section 116b.

In this embodiment, the inter-hierarchy interleaving section 115a performs segment unit interleaving as frequency interleaving. FIG. 5 is a diagram showing the basic operation of such segment-by-segment interleaving. As shown in FIG. 5(a), the partial reception band .alpha. 0 to No. It consists of 9 segments up to 8. Inter-hierarchy interleaving section 115a arranges segments constituting partial reception band data (partial reception band α) in accordance with an interleave table that defines the correspondence relationship between segment numbers before interleaving and segment numbers after interleaving, for example, as shown in FIG. The arrangement shown in a) is changed to the arrangement shown in FIG. 5(b).

In the present embodiment, inter-layer interleaving section 115a may interleave the partial reception band data in units of segments regardless of the SP pattern in the partial reception band data. As a result, the processing can be simplified compared to the case where inter-segment interleaving and segment-by-segment interleaving are selectively used according to the SP pattern.

When performing segment-by-segment interleaving, inter-hierarchy interleaving section 115a switches the correspondence relationship between the segment number before interleaving and the segment number after interleaving at a switching cycle consisting of one or more symbols. An example in which the switching cycle is a time length of one symbol will be described below, but the switching cycle may be a time length of two symbols, for example.

As a result, the data of one hierarchy will not continue to use the segment with the same segment number. In other words, the segment numbers used by the data of one layer are dynamically switched over time. For example, if only one segment of the A layer is included in the partial reception band of 9 segments, and the remaining 8 segments are the B layer, the segment number (i.e., frequency position) of the A layer of the partial reception band changes due to interleaving. As a result, the effect of widening the band to 9 segment bands can be obtained.

On the other hand, inter-hierarchy interleaving section 115b may perform inter-segment interleaving or segment-by-segment interleaving as frequency interleaving. The inter-layer interleaving section 115b performs inter-segment interleaving when the SP patterns are the same in the B layer and the C layer. On the other hand, when the SP patterns are different between the B layer and the C layer, segment unit interleaving is performed. However, when the non-partial reception part includes only the C layer, inter-segment interleaving is applied regardless of the SP pattern of the B layer and the C layer.

Band-specific intra-segment interleaving sections 116 (116a, 116b) apply intra-segment interleaving to each of the partial reception band data and the non-partial reception band data output from band-specific inter-layer interleaving sections 115 (115a, 115b). , and outputs the partial reception band data and the non-partial reception band data after intra-segment interleaving to band synthesizing section 117 .

For example, the intra-segment interleaving section 116a performs carrier rotation and carrier randomization within the segment that constitutes the partial reception band data output from the inter-layer interleaving section 115a, and combines the partial reception band data after carrier rotation and carrier randomization. Output to unit 117 . On the other hand, intra-segment interleaving section 116b performs carrier rotation and carrier randomization within a segment constituting the non-partial reception band data output from inter-layer interleaving section 115b, and converts the non-partial reception band data after carrier rotation and carrier randomization to Output to band synthesizing section 117 .

The band synthesizing section 117 synthesizes the partial reception band data and the non-partial reception band data output from the intra-segment interleaving section 116 (116a, 116b) for each band, and puts the synthesized transmission data (system 1 data sequence) into a frame. output to conversion unit 118 .

Framing section 118 forms an OFDM frame from the transmission data output from band combining section 117 and outputs the OFDM frame to IFFT section 119 .

IFFT section 119 performs IFFT on the OFDM frame output from framing section 118 to generate an OFDM signal, and outputs the generated OFDM signal to GI adding section 120 .

GI imparting section 120 imparts a GI (Guard Interval) to the OFDM signal output from IFFT section 119, and outputs the OFDM signal to which the GI has been imparted. The OFDM signal output from the GI imparting unit 120 is converted into a radio signal by a radio transmitter (not shown) and transmitted via a polarized antenna.

System 2 transmission section 130 differs from system 1 transmission section 110 to which system 1 data sequences are input in that system 2 data sequences are input, but system 2 transmission section 130 is similar to system 1 transmission section 110. have a configuration.

System 2 transmitting section 130 includes layer separation section 131, layer-specific time interleaving section 132 (132a, 132b, 132c), layer-specific intersegment interleaving section 133 (133a, 133b, 133c), and partial reception band division. section 134, inter-layer interleaving section 135 (135a, 135b) for each band, intra-segment interleaving section 136 (136a, 136b) for each band, band synthesis section 137, framing section 138, and IFFT section 139 , and a GI assigning unit 140 .

Here, the layer separating unit 131 of the 2-system transmitting unit 130, the time interleaving unit 132 (132a, 132b, 132c) for each layer, the inter-segment interleaving unit 133 (133a, 133b, 133c) for each layer, the partial reception band dividing unit 134, inter-layer interleaving units 135 (135a, 135b) for each band, intra-segment interleaving units 136 (136a, 136b) for each band, band synthesizing unit 137, framing unit 138, IFFT unit 139, and GI adding unit 140 , the layer separating unit 111 of the system 1 transmitting unit 110, the time interleaving unit 112 (112a, 112b, 112c) for each layer, the inter-segment interleaving unit 113 (113a, 113b, 113c) for each layer, the partial reception band dividing unit 114, Corresponds to inter-layer interleaving section 115 (115a, 115b) for each band, intra-segment interleaving section 116 (116a, 116b) for each band, band synthesizing section 117, framing section 118, IFFT section 119, and GI adding section 120, respectively. do.

In particular, in system 2 transmitting section 130, inter-layer interleaving section 135a for the partial reception band performs segment unit interleaving as frequency interleaving. When performing segment-by-segment interleaving, inter-hierarchy interleaving section 135a switches the correspondence relationship between the segment number before interleaving and the segment number after interleaving at a switching cycle.

As a result, the data of one hierarchy will not continue to use the segment with the same segment number. In other words, the segment numbers used by the data of one layer are dynamically switched over time. For example, if only one segment of the A layer is included in the partial reception band of 9 segments, and the remaining 8 segments are the B layer, the segment number (i.e., frequency position) of the A layer of the partial reception band changes due to interleaving. As a result, the effect of widening the band to 9 segment bands can be obtained.

However, the correspondence relationship between the segment number before interleaving and the segment number after interleaving is the same between system 1 transmitting section 110 (inter-layer interleaving section 115a) and system 2 transmitting section 130 (inter-layer interleaving section 135a), and If the correlation between the frequency characteristics of the system transmitting section 110 and the system 2 transmitting section 130 is large, a transmission error may occur in the data of the same segment number in the same layer in the system 1 transmitting section 110 and the system 2 transmitting section 130 .

For example, the A layer has only one segment, and the 1-system transmitting unit 110 (inter-layer interleaving unit 115a) and the 2-system transmitting unit 130 (inter-layer interleaving unit 135a) transmit the A layer data from the segment number "A" before interleaving. When rearranged to segment number “B” after interleaving, segment number “B” transmitted by system 1 transmitting unit 110 and segment number “B” transmitted by system 2 transmitting unit 130 are changed due to the influence of frequency selective fading. Both can be in error. As a result, burst-like errors that cannot be corrected by error correction may occur in layer A data.

Therefore, in the present embodiment, when segment unit interleaving is performed, the correspondence relationship between the segment number before interleaving and the segment number after interleaving is the correspondence relationship used by the 1-system transmission unit 110 and the correspondence relationship used by the 2-system transmission unit 130. be different from each other.

Specifically, each of system 1 transmitting section 110 (inter-layer interleaving section 115a) and system 2 transmitting section 130 (inter-layer interleaving section 135a) performs interleaving on a segment basis. The interleave table that defines the correspondence between segment numbers is switched at the switching cycle. Here, within the same switching period, the interleave table used by system 1 transmitting section 110 (inter-layer interleaving section 115a) and the interleave table used by system 2 transmitting section 130 (inter-layer interleaving section 135a) are different from each other.

This reduces the possibility that both of the two systems will fall at the same time, so it is possible to improve transmission characteristics when performing segment-by-segment interleaving in the MIMO transmission scheme. For example, the system 1 transmission unit 110 (inter-layer interleaving unit 115a) rearranges the A-layer data from the segment number "A" before interleaving to the segment number "B" after interleaving, and the system 2 transmitting unit 130 (inter-layer interleaving unit 115a) The section 135a) rearranges the A layer data from the segment number "A" before interleaving to the segment number "C" after interleaving. As a result, even if the segment number "B" drops, the segment number "C" can be transmitted without any problem, thereby suppressing the possibility of an uncorrectable burst error.

FIG. 6 is a diagram showing configuration example 1 of the inter-layer interleaving section 115a of the 1-system transmitting section 110 and the inter-layer interleaving section 135a of the 2-system transmitting section 130 according to the present embodiment.

As shown in FIG. 6, inter-layer interleaving section 115a of system 1 transmitting section 110 has system 1 interleave table holding section 1151a and system 1 segment unit interleaving section 1152a. Interlayer interleaving section 135a of system 2 transmitting section 130 has system 2 interleave table holding section 1351a and system 2 segment unit interleaving section 1352a.

Each of the system 1 interleave table holding unit 1151a and the system 2 interleave table holding unit 1351a holds a plurality of interleave tables. Here, a plurality of interleave tables are individually prepared for each of the 1-system interleave table holding unit 1151a and the 2-system interleave table holding unit 1351a.

The 1-system segment unit interleaving unit 1152a switches the interleave table used for the segment unit interleaving from among the plurality of interleave tables held by the 1-system interleave table holding unit 1151a at a switching cycle. The 2-system segment unit interleaving unit 1352a switches the interleave table used for segment unit interleaving from among the plurality of interleave tables held by the 2-system interleave table holding unit 1351a at a switching cycle.

FIG. 7 is a diagram showing an example of an interleave table respectively held by the 1-system interleave table holding unit 1151a and the 2-system interleave table holding unit 1351a. FIG. 7 shows an example in which the switching period is a time length of one symbol. Although each table shown in FIG. 7 shows the arrangement of symbol numbers after interleaving, the arrangement shown in FIG. 5(a) can be used as the symbol numbers before interleaving.

FIG. 7A shows an example of the interleave table held by the system 1 interleave table holding unit 1151a. FIG. 7B shows an example of the interleave table held by the 2-system interleave table holding unit 1351a. As shown in FIGS. 7A and 7B, the interleave table corresponding to each symbol number is different between system 1 and system 2. FIG.

In this way, by preparing a plurality of interleave tables independently for the 1st and 2nd systems and switching the table to be used for each symbol, the interleave table is changed for each symbol. It is possible to prevent segments in the A layer from always having the same segment number.

FIG. 8 is a diagram showing configuration example 2 of the inter-layer interleaving section 115a of the 1-system transmitting section 110 and the inter-layer interleaving section 135a of the 2-system transmitting section 130 according to the present embodiment.

In this configuration example 2, each of the inter-layer interleaving unit 115a of the system 1 transmitting unit 110 and the inter-layer interleaving unit 135a of the system 2 transmitting unit 130 switches the interleave table by cyclically shifting the basic interleave table at the switching cycle. switch in cycles. Here, the shift pattern in which inter-layer interleaving section 115a of system 1 transmitting section 110 cyclically shifts the basic interleave table and the shift pattern in which inter-layer interleaving section 135a of system 2 transmitting section 130 cyclically shifts the basic interleave table are mutually different. different.

As shown in FIG. 8, inter-layer interleaving section 115a of system 1 transmitting section 110 has rightward cyclic shift section 1153a and system 1 segment unit interleaving section 1152a. Interlayer interleaving section 135a of system 2 transmitting section 130 has leftward cyclic shift section 1353a and system 2 segment unit interleaving section 1352a.

The rightward cyclic shift unit 1153a performs rightward cyclic shift on the basic interleave table held by the basic interleave table holding unit 150 at the switching cycle. On the other hand, leftward cyclic shift section 1353a performs leftward cyclic shift on the basic interleave table held by basic interleave table holding section 150 at the switching cycle.

FIG. 9 is a diagram showing an example of a basic interleave table and an interleave table after cyclic shift. FIG. 9 shows an example in which the switching period is a time length of one symbol.

FIG. 9(a) shows an example of the basic interleave table. FIG. 9(b) shows an example of the interleave table after the cyclic shift to the right. FIG. 9(c) shows an example of the interleave table after leftward cyclic shift. As shown in FIGS. 9(b) and 9(c), due to the cyclic shift, the interleave tables corresponding to the symbol numbers #1 to #8 are different between system 1 and system 2. FIG.

In this way, by cyclically shifting the basic table for each symbol, the same segment number will not always be used for the segment of the A layer between the 1st system and the 2nd system.

However, in the example of FIG. 9, the same interleave table is used for the first symbol (symbol number #0) between the 1 system and the 2 system. For this reason, as shown in FIG. 10, a configuration may be adopted in which an offset shift is given to one system so that a different table is always used. Here, assuming that the partial reception band is N segments, the offset amount is an integer of 1 or more and N-1 or less.

In the example of FIG. 9, system 1 is cyclically shifted to the right and system 2 is cyclically shifted to the left. It is also possible to use a shift amount of 2 or 4 instead of 1 each. Here, assuming that the partial reception band is N segments, the shift amount is an integer of 1 or more and N-1 or less.

(receiving device)
Next, the configuration of the receiving device in the digital broadcasting system according to this embodiment will be described. FIG. 11 is a diagram showing the configuration of a receiving device 300 in the digital broadcasting system according to this embodiment.

As shown in FIG. 11, receiving apparatus 300 is configured to perform reverse processing of the processing performed by transmitting apparatus 100 shown in FIG. Receive series. However, the MIMO transmission is not limited to two systems, and a MIMO transmission system of three or more systems may be applied.

In addition, receiving device 300 receives hierarchical transmission up to three hierarchical levels in each of the two systems. Specifically, the receiving device 300 according to the present embodiment can receive layer A data, layer B data, and layer C data. Receiving apparatus 300 has 1-system receiving section 310 , 2-system receiving section 330 , system combining section 301 , demapping section 302 , and inverse BICM section 303 .

System 1 receiving section 310 includes GI removing section 311, FFT section 312, deframing section 313, band separating section 314, intra-segment deinterleaving section 315 (315a, 315b) for each band, and Inter-hierarchical deinterleaving units 316 (316a, 316b), partial reception band synthesizing units 317, inter-hierarchical inter-segment deinterleaving units 318 (318a, 318b, 318c), and hierarchical time deinterleaving units 319 (319a, 319b, 319c) and a hierarchical synthesizing unit 320.

The GI removal unit 311 removes the GI added to the received 1-system OFDM signal, and outputs the OFDM signal after the GI removal.

FFT section 312 performs FFT on the OFDM signal output from GI removing section 311 to generate an OFDM frame, and outputs the generated OFDM frame to deframing section 313 .

Deframing section 313 converts the OFDM frame output from FFT section 312 into reception data, and outputs the reception data to band separation section 314 .

The band separation unit 314 separates and acquires the partial reception band data and the non-partial reception band data from the reception data output from the deframing unit 313, and outputs the partial reception band data to the intra-segment deinterleaving unit 315a. At the same time, it outputs the non-partial reception band data to intra-segment deinterleaving section 315b.

The intra-segment de-interleaving unit 315a for the partial reception band among the intra-segment de-interleaving units 315 (315a, 315b) for each band performs reverse processing of carrier rotation and carrier randomization within the segment forming the partial reception band data. Then, the partial reception band data subjected to such processing is output to inter-layer deinterleaving section 316a. On the other hand, the intra-segment deinterleaving section 315b for the non-partial reception band performs reverse processing of the carrier rotation and carrier randomization within the segment constituting the non-partial reception band data, The reception band data is output to inter-layer deinterleaving section 316b.

The inter-layer deinterleaving units 316 (316a, 316b) by band divide the frequency of the partial reception band data and the non-partial reception band data output from the intra-segment deinterleaving units 315 (315a, 315b) by band. Deinterleave is performed, and the partial reception band data and non-partial reception band data after frequency deinterleaving are output to partial reception band synthesizing section 317 .

In this embodiment, the inter-layer deinterleaving unit 316a performs segment unit deinterleaving as frequency deinterleaving. The inter-hierarchy deinterleaving unit 316a arranges segments constituting the partial reception band data (partial reception band α) according to a deinterleave table that defines the correspondence relationship between the segment numbers before deinterleaving and the segment numbers after deinterleaving, For example, the arrangement shown in FIG. 5(b) is changed to the arrangement shown in FIG. 5(a). When inter-layer deinterleaving section 316a performs segment-by-segment interleaving, it switches the correspondence relationship between the segment number before deinterleaving and the segment number after deinterleaving at a switching cycle.

On the other hand, the inter-layer de-interleaving unit 316b may perform inter-segment interleaving or segment-by-segment interleaving as frequency interleaving.

The partial reception band synthesizing unit 317 combines the partial reception band data output from the inter-layer deinterleaving unit 316a and the non-partial reception band data output from the inter-layer deinterleaving unit 316b into layer A data, layer B data, and layer C data. Hierarchical data is acquired, A hierarchical data is output to inter-segment deinterleaver 318a, B hierarchical data is output to intersegment deinterleaver 318b, and C hierarchical data is output to intersegment deinterleaver 318c.

Hierarchical inter-segment deinterleaving units 318 (318a, 318b, 318c) perform frequency deinterleaving on a carrier-by-carrier basis across all segments that make up the A hierarchy, output the A hierarchy data to the time deinterleaving unit 319a, Frequency deinterleaving is performed on a carrier-by-carrier basis over all segments constituting the hierarchy, B-layer data is output to the time deinterleaving unit 319b, frequency de-interleaving is performed on a carrier-by-carrier basis over all segments constituting the C hierarchy, and the C hierarchy is generated. The data is output to the time deinterleaver 319c.

The layer-by-layer time deinterleaving units 319 ( 319 a , 319 b , 319 c ) perform time deinterleaving on each of the A layer data, the B layer data, and the C layer data, and output them to the layer combining unit 320 .

The layer synthesizing unit 320 synthesizes the A-layer data, the B-layer data, and the C-layer data output from the hierarchical time deinterleaving units 319 (319a, 319b, and 319c) to generate a 1-system data series, and generates The resulting 1-system data series is output to system synthesis section 301 .

The 2-system receiver 330 differs from the 1-system receiver 310 in that it receives the 2-system signal, but the 2-system receiver 330 has the same configuration as the 1-system receiver 310. have.

System 2 receiving section 330 includes GI removing section 331, FFT section 332, deframing section 333, band separating section 334, intra-segment deinterleaving section 335 (335a, 335b) for each band, and Inter-hierarchical deinterleaving units 336 (336a, 336b), partial reception band synthesizing units 337, inter-hierarchical inter-segment deinterleaving units 338 (338a, 338b, 338c), and hierarchical time deinterleaving units 339 (339a, 339b, 339c) and a layer synthesizing unit 340.

In system 2 receiving section 330, inter-layer deinterleaving section 336a for the partial reception band performs segment unit deinterleaving as frequency deinterleaving. When performing segment-by-segment deinterleaving, the inter-hierarchy deinterleaving unit 336a switches the correspondence relationship between the segment number before deinterleaving and the segment number after deinterleaving at a switching cycle.

In the present embodiment, when segment unit deinterleaving is performed, the correspondence relationship between the segment number before deinterleaving and the segment number after deinterleaving is the correspondence relationship used by the 1-system transmission unit 110 and the correspondence relationship used by the 2-system transmission unit 130. and differ from each other.

Specifically, each of the system 1 receiving unit 310 (inter-layer deinterleaving unit 316a) and the system 2 receiving unit 330 (inter-layer deinterleaving unit 336a) performs segment unit deinterleaving. The deinterleave table that defines the correspondence relationship of segment numbers after deinterleaving is switched at a switching cycle. Here, within the same switching period, the deinterleaving table used by the system 1 receiving unit 310 (inter-layer deinterleaving unit 316a) and the deinterleaving table used by the system 2 receiving unit 330 (inter-layer deinterleaving unit 336a) are different from each other.

FIG. 12 is a diagram showing a configuration example 1 of the inter-layer deinterleaving section 316a of the system 1 receiving section 310 and the inter-layer deinterleaving section 336a of the system 2 receiving section 330 according to this embodiment.

As shown in FIG. 12, inter-layer deinterleaving section 316a of system 1 receiving section 310 has system 1 deinterleaving table holding section 3161a and system 1 segment unit deinterleaving section 3162a. The inter-layer deinterleaving section 336a of the 2-system receiving section 330 has a 2-system deinterleaving table holding section 3361a and a 2-system segment unit de-interleaving section 3362a.

Each of the 1-system deinterleave table holding unit 3161a and the 2-system deinterleave table holding unit 3361a holds a plurality of deinterleave tables. Here, a plurality of deinterleave tables are individually prepared for each of the 1-system deinterleave table holding unit 3161a and the 2-system deinterleave table holding unit 3361a.

The 1-system segment unit deinterleaving unit 3162a switches the deinterleave table used for segment unit deinterleaving from among the plurality of deinterleave tables held by the 1-system deinterleave table holding unit 3161a at a switching cycle. The 2-system segment unit deinterleaving unit 3362a switches the deinterleave table used for segment unit deinterleaving from among the plurality of deinterleave tables held by the 2-system deinterleave table holding unit 3361a at a switching cycle.

In this way, a plurality of deinterleave tables are prepared independently for the 1st system and the 2nd system, and the table to be used is switched for each symbol, thereby changing the deinterleave table for each symbol.

FIG. 13 is a diagram showing a configuration example 2 of the inter-layer deinterleaving section 316a of the system 1 receiving section 310 and the inter-layer deinterleaving section 336a of the system 2 receiving section 330 according to this embodiment.

In this configuration example 2, each of the inter-layer deinterleaving unit 316a of the system 1 receiving unit 310 and the inter-layer deinterleaving unit 336a of the system 2 receiving unit 330 cyclically shifts the basic deinterleaving table at the switching cycle to The interleave table is switched at the switching cycle. Here, a shift pattern in which the basic deinterleave table is cyclically shifted by the inter-layer deinterleaving unit 316a of the system 1 receiving unit 310 and a shift pattern in which the basic deinterleaving table is cyclically shifted by the inter-layer deinterleaving unit 336a of the system 2 receiving unit 330 patterns are different from each other.

As shown in FIG. 13, inter-hierarchy deinterleaving section 316a of system 1 receiving section 310 has leftward cyclic shift section 3163a and system 1 segment unit deinterleaving section 3162a. Inter-layer deinterleaving section 336a of system 2 receiving section 330 has rightward cyclic shift section 3363a and system 2 segment unit deinterleaving section 3362a.

The leftward cyclic shift unit 3163a performs leftward cyclic shift on the basic deinterleave table held by the basic deinterleave table holding unit 350 at the switching cycle. On the other hand, rightward cyclic shift section 3363a performs rightward cyclic shift on the basic deinterleave table held by basic deinterleave table holding section 350 at the switching cycle.

Returning to FIG. 11 , system synthesizing section 301 synthesizes system 1 reception data output from system 1 reception section 310 and system 2 reception data output from system 2 reception section 330 , and demaps section 302 . output to

Demapping section 302 demaps the received data from the modulated symbols of the received data output from system combining section 301 and outputs the received data to inverse BICM section 303 .

Inverse BICM section 303 performs error correction decoding and bit deinterleaving on the received data output from demapping section 302 using BICM.

(Summary of embodiment)
The transmitting apparatus 100 according to the present embodiment has a 1-system transmitting section 110 and a 2-system transmitting section 130 that transmit 2-system data sequences using the MIMO transmission scheme. When frequency interleaving is performed in segment units, each of system 1 transmitting section 110 and system 2 transmitting section 130 sets the correspondence relationship between the segment number before interleaving and the segment number after interleaving to a switching period consisting of one or more symbols. to switch. Here, the correspondence relationship used by the 1-system transmission section 110 and the correspondence relationship used by the 2-system transmission section 130 are different from each other within the same switching period.

A receiving apparatus 300 according to this embodiment has a 1-system receiving section 310 and a 2-system receiving section 330 that receive two systems of data sequences using the MIMO transmission scheme. When frequency deinterleaving is performed in segment units, each of system 1 receiving section 310 and system 2 receiving section 330 determines the correspondence relationship between the segment number before deinterleaving and the segment number after deinterleaving from one or more symbols. switching at different switching cycles. Here, within the same switching period, the correspondence relationship used by the 1-system reception unit 310 and the correspondence relationship used by the 2-system reception unit 330 are different from each other.

If the same segment number is always used for transmission due to frequency selective fading that has a large correlation between systems 1 and 2, systems 1 and 2 will be affected at the same time, and there is a possibility of bursty errors after system synthesis. be. According to this embodiment, by transmitting with different segment numbers for the 1st system and the 2nd system, it is possible to reduce the possibility of being affected at the same time and suppress burst errors after system synthesis.

Next, the effect of this embodiment will be explained using a simulation of error rate characteristics. The error rate characteristics of layer A were compared for the following three types of interleaving methods.

1) A method of transmitting without changing the interleave table for each symbol.

2) A method of transmitting by changing the interleave table for each symbol, in which cyclic shifts in the same direction are used for the 1st system and the 2nd system.

3) A method of transmitting by changing the interleave table for each symbol, in which reverse cyclic shifts are used between the 1st system and the 2nd system.

In this simulation, MIMO transmission was performed in a two-wave multipath environment. Also, the number of layers is 2, the A layer has 3 segments, and the B layer has 30 segments. The modulation scheme of layer A is 16QAM modulation.

FIG. 14(a) shows the frequency characteristics of the transmission line when the signal power ratio of the two waves is 0 dB, the arrival time difference is 0.5 μs, and the two waves are in phase. FIG. 14(b) shows the error rate of layer A with respect to the signal-to-noise ratio (CNR). The required CNR is the minimum CNR that achieves pseudo-error free when the error rate is 1.0×10 ⁻³ or less.

As shown in FIG. 14(b), the required CNR was 15.0 dB when the tables were cyclically shifted in the same direction for transmission in the 1st and 2nd systems. On the other hand, the required CNR was 12.6 dB when the table was cyclically shifted and transmitted in the reverse direction between the 1st system and the 2nd system. When the cyclic shift directions were reversed between the 1st system and the 2nd system, the error rate performance was improved by 2.4 dB.

(Other embodiments)
In the embodiment described above, an example has been described in which inter-layer interleaving section 115a of transmitting apparatus 100 interleaves partial reception band data in units of segments regardless of the SP pattern in the partial reception band data. However, inter-layer interleaving section 115a may switch between interleaving partial reception band data in segment units and interleaving partial reception band data in carrier units based on the SP pattern in the partial reception band data.

Also, in the above-described embodiment, an example of switching the interleave table for each symbol in inter-layer interleaving section 115a for the partial reception band of transmitting apparatus 100 has been described. However, such interleave table switching processing can also be applied to inter-layer interleaving section 115b for the non-partial reception band. In such a case, inter-layer interleaving section 115b for the non-partial reception band has the same configuration as inter-layer interleaving section 115a. Further, it can be done in a similar manner for 33 or 35 segments of the full band. Specifically, when segment-based interleaving is performed for the entire band (the partial reception band and the non-partial reception band), the interleave table may be switched at a switching cycle.

Further, in the above-described embodiment, an example in which the transmitting apparatus 100 interleaves the signal before the OFDM frame configuration in segment units, and the receiving apparatus 300 deinterleaves the deframed signal in segment units. explained. However, a configuration may be adopted in which transmitting apparatus 100 interleaves the signal after forming the OFDM frame in units of segments, and receiving apparatus 300 deinterleaves the signal before deframing in units of segments.

In the above-described embodiment, the case of performing hierarchical transmission of three layers (A layer, B layer, and C layer) has been described as an example. It can also be applied to the case of hierarchical transmission of B layer).

A program that causes a computer to execute each process performed by the transmitting device 100 and the receiving device 300 may be provided. Also, each of the transmitting device 100 and the receiving device 300 may be configured as a semiconductor integrated circuit (chip).

100: transmitting device 101: BICM unit 102: mapping unit 103: system separation unit 110: 1 system transmission unit 111: layer separation unit 112: time interleaving unit 113: inter-segment interleaving unit 114: partial reception band division unit 115: inter-layer Interleaving section 116 : intra-segment interleaving section 117 : band synthesizing section 118 : framing section 119 : IFFT section 120 : GI adding section 130 : secondary transmission section 131 : layer separation section 132 : time interleaving section 133 : inter-segment interleaving section 134 : Partial reception band dividing unit 135 : Inter-layer interleaving unit 136 : Intra-segment interleaving unit 137 : Band synthesizing unit 138 : Framing unit 139 : IFFT unit 140 : GI adding unit 150 : Basic interleave table holding unit 300 : Receiving device 301 : System synthesis unit 302 : Demapping unit 303 : Inverse BICM unit 310 : System 1 reception unit 311 : GI removal unit 312 : FFT unit 313 : Deframing unit 314 : Band separation unit 315 : Intra-segment deinterleaving unit 316 : Inter-layer Deinterleaving section 317 : Partial reception band synthesis section 318 : Inter-segment deinterleaving section 319 : Time deinterleaving section 320 : Hierarchical synthesis section 330 : Secondary reception section 331 : GI removal section 332 : FFT section 333 : Deframing section 334 : band separating unit 335 : intra-segment deinterleaving unit 336 : inter-layer deinterleaving unit 337 : partial reception band synthesizing unit 338 : inter-segment deinterleaving unit 339 : time deinterleaving unit 340 : layer synthesizing unit 350 : basic deinterleaving table holding Unit 1151a: System 1 interleave table holding unit 1152a: System 1 segment unit interleaving unit 1153a: Rightward cyclic shift unit 1351a: System 2 interleave table holding unit 1352a: System 2 segment unit interleaving unit 1353a: Leftward cyclic shift unit 3161a: System 1 data Interleave table holding unit 3162a: 1st system segment unit deinterleaving unit 3163a: Leftward cyclic shift unit 3361a: 2nd system deinterleave table holding unit 3362a: 2nd system segment unit deinterleaving unit 3363a: Rightward cyclic shift unit

Claims (2)

A transmitting device used in a digital broadcasting system in which a frequency band of a broadcasting channel is divided into a plurality of segments,
Equipped with two transmission units for transmitting two data sequences using the MIMO transmission method,
When frequency interleaving is performed in segment units, each of the two transmission units stores an interleave table that defines the correspondence relationship between the segment number before interleaving and the segment number after interleaving, and a switching cycle consisting of one or more symbols. switch with
Within the same switching period, the interleave table used by one of the two transmission units and the interleave table used by the other transmission unit of the two transmission units. different from each other
Each of the two transmission units switches the interleave table at the switching cycle by cyclically shifting the basic interleave table that defines the correspondence relationship at the switching cycle,
A transmitting apparatus, wherein a shift pattern for cyclically shifting the basic interleave table by the transmitting unit of one system and a shift pattern for cyclically shifting the basic interleave table by the transmitting unit of the other system are different from each other. . A receiving device for use in a digital broadcasting system in which a frequency band of a broadcasting channel is divided into a plurality of segments,
Equipped with two receiving units for receiving two data sequences using the MIMO transmission method,
When frequency deinterleaving is performed in segment units, each of the two systems of receiving units stores a deinterleave table that defines the correspondence relationship between the segment number before deinterleaving and the segment number after deinterleaving one or more symbols. switching with a switching period consisting of
Within the same switching cycle, the deinterleave table used by one of the two systems of receivers and the deinterleave table used by the other of the two systems of receivers. are different from each other,
Each of the two systems of receiving units switches the deinterleave table at the switching cycle by cyclically shifting a basic deinterleave table that defines the correspondence relationship at the switching cycle,
A shift pattern for cyclically shifting the basic deinterleaving table by the receiving unit of one system and a shift pattern for cyclically shifting the basic deinterleaving table by the receiving unit of the other system are different from each other. receiving device.

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