JP2003060610A - Time interleave method and time deinterleave method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a time interleave method for minimizing memory size and at the same time processing time, and to provide a time deinterleave method. SOLUTION: The amount of memory for storing the modulation symbol of each carrier for time interleave is obtained for each carrier by length I of time interleave × (a serial carrier number i ×5) mod96}, an address value corresponding to an obtained amount of memory is set to be the initial value of address to each carrier in the order of carriers, an address number is increased by one for each input of OFDM symbols, a symbol stored in the region of the amount of memory is read from the initial value of the address of each carrier for time interleave output and at the same time the next input symbol is written to the address, the address number is increased by one, and an address is specified so that the address is returned to the initial value when the result address number that has been increased by one reaches the upper-limit value of the address value of the amount of memory obtained for each carrier.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a time interleaving method and a time deinterleaving method used for terrestrial digital broadcasting.

[0002]

2. Description of the Related Art A terrestrial digital broadcasting transmission line coding method has been reported under the technical conditions of terrestrial digital broadcasting. According to it, OFDM (Orthogonal Frequency Division Multi) is used as a transmission method of terrestrial digital broadcasting.
plexing Orthogonal frequency division multiplexing) is used. Broadcast data defined by the terrestrial digital broadcasting channel coding method is composed of a group of data (also referred to as a data segment) consisting of a plurality of transport stream packets, and a pilot signal for synchronization acquisition is included in the data segment. Thirteen added OFDM blocks (also referred to as OFDM segments) are combined and transmitted.

Further, according to this method, hierarchical transmission is possible in which a plurality of layers having different transmission characteristics are simultaneously transmitted. Each layer is composed of one or more data segments, and the carrier modulation method, the coding rate of the inner code, and the
And parameters such as the length of time interleaving can be specified.

In the channel coding of this terrestrial digital broadcasting, time-interleaved is performed to ensure anti-fading performance by temporally dispersing adjacent modulated data. When the hierarchical transmission is performed, the hierarchical division is performed according to the designation of the hierarchical information, and the parallel processing of up to three systems is performed.

Further, by designating the length of the time interleave on a layer-by-layer basis, a different transmission line for each layer,
That is, when different reception forms for each layer are targeted, it is possible to set an optimal time interleave length for each transmission path.

The structure for time interleaving is as shown in FIG. 23 for the hierarchically combined signal, and interleaving is performed in units of modulation symbols (units of I and Q axes). In FIG. 23, each block shows the structure of the time interleave in the data segment, and the value of nc is 96 (the number of carriers) in the transmission mode 1, 192 (the number of carriers) in the transmission mode 2, and the transmission mode. In the case of 3, it is 384 (the number of carriers).

The length I of the time interleave can be selected from 0, 4, 8, and 16 in the transmission mode 1, and in the transmission mode 2,
0, 2, 4, 8 can be selected and 0, 1,
It is specified that 2 or 4 can be selected.

Here, the time interleaving in the data segment is performed using the FIFO, and the storage capacity of each FIFO is I × mi, and mi = (i × 5) mod96.
Is. i is the number of carriers sequentially numbered from 0, and I is the length of time interleave that can be specified in hierarchical units.

27A and 27B show the transmission mode 1
In the case of, the storage capacity of the FIFO for the numbers 0 to 95 of each carrier is shown for each selectable time interleave length. FIGS. 28 (a) and 28 (b) show the transmission mode 2
The storage capacity of the FIFO for the carrier numbers 0 to 191 is shown for each selectable time interleave length in the case of FIG. 29, and FIGS. 29A and 29B show the selectable time interleave length in the case of the transmission mode 3. Each time, the storage capacity of the FIFO for the numbers 0 to 383 of each carrier is shown.

Therefore, as shown in FIG. 24, with reference to FIGS. 27 to 29, the maximum number of symbol buffers per data segment (hereinafter, also referred to as maximum symbol buffer amount) is the transmission mode 1, When the time interleaving length I = 16, the maximum symbol buffer amount occurs at the carrier number 19 and becomes 1520. When the transmission mode 2 and the time interleaving length I = 8, the carrier numbers 19 and 115 are set. Occasionally,
The maximum symbol buffer amount becomes 760, and when the transmission mode 3 and the time interleaving length I = 4, the maximum symbol buffer amount occurs at carrier numbers 19, 115, 211 and 307, and the maximum symbol buffer amount becomes 380.

In the case of the transmission mode 1, the interleaving length I = 4 and the 95th carrier,
The storage capacity Zi of the symbol buffer is Zi = I × (95
X5) mod96 = Ix91. The storage capacity of the symbol buffer is also simply referred to as the symbol buffer amount.

Therefore, when the interleave length I = 4, the symbol buffer amount Z ₉₅ = 364 bytes, and when the time interleave length I = 8, the symbol buffer amount Z ₉₅ = 728 bytes, the time interleave length I =
When it is 16, the symbol buffer amount Z _{95 is} 1456 bytes, (1 byte 32 bits, I and Q 16 bits).

The total symbol buffer amount in FIG. 24 is the sum of the symbol buffer amounts of the respective carriers per data symbol, the total symbol buffer amount Z is Z = Σ (I × mi), and the transmission mode is When 1 and I = 8, the total symbol buffer amount is Z = 36480, and when transmission mode 1 and I = 16, the total symbol buffer amount is Z = 72960.

As is apparent from FIG. 24, for time interleaving, if each transmission mode is considered as a single, the total symbol buffer amount per data segment is 72960 bytes at maximum, and is the same, but all transmission modes are the same. In this case, it is necessary to prepare a symbol buffer amount for 384 carriers in transmission mode 3.

In the transmission mode 3, the maximum is 38.
It only requires 0 bytes, but in order to support the transmission mode 1, it is necessary to prepare a maximum symbol buffer amount of 1520 bytes.

The structure for the time interleaving in the data segment in FIG. 23 is schematically shown in FIG. 25, which is composed of a FIFO having a storage capacity defined for each carrier symbol, and the storage capacity of each FIFO. Is shown in the box.

Therefore, as shown in FIG. 26 in which the carrier number i is displayed in the left column in each of the transmission modes 1, 2, and 3, the carrier numbers 0 to 95 are set for the transmission mode 1.
For the transmission mode 2, the symbol buffers for the carrier numbers 0 to 95 in the transmission mode 1 are used, and the carrier numbers 96 to
191, a symbol buffer is provided, and transmission mode 3
, The carrier number 0 in the case of transmission mode 1
The symbol buffer for 95 and the symbol buffer for carrier numbers 96 to 191 in the case of the transmission mode 2 are used, and the symbol buffers for carrier numbers 192 to 383 are provided to support.

Therefore, as shown in FIG. 25, a maximum storage capacity of 72960 bytes is required for carrier numbers 0 to 95, and subsequent carrier numbers 96 to 191.
Is required to have a maximum storage capacity of 36480 bytes, and subsequent carrier numbers 192-383 need to have a maximum storage capacity of 36480 bytes, and the maximum required storage capacity is 145920 bytes.

Since this requires 13 segments, 1
45920 × 13 = 1896960 bytes are required.
However, since it is sufficient to compare one data segment, one data segment will be described.

[0020]

However, as described above, when the conventional time interleaving method is used, since up to three layers can be transmitted, a maximum of three parallel circuits is required for each layer.

Further, there is a problem that the maximum symbol buffer amount according to the transmission mode and the length of the time interleave is required, and the circuit scale becomes large.

Further, when the symbol buffer having the maximum storage capacity is prepared and the time interleaving is performed, it is necessary to store the data for the maximum symbol buffer even when the time interleaving length is short and the symbol buffer amount is small. Therefore, there is a problem that the processing time of time interleaving and time deinterleaving becomes long.

It is an object of the present invention to provide a time interleaving method and a time deinterleaving method that minimize the processing time while minimizing the memory scale.

[0024]

A time interleaving method according to the present invention is a time interleaving method for performing time interleaving by a memory, wherein I is the length of the time interleaving, and carrier numbers i are sequentially numbered from 0. , 0, ..., nc {(nc = 95 (in transmission mode 1), nc = 191 (in transmission mode 2) nc = 38
3 (in transmission mode 3)}, mi is (i × 5) mod
When 96 is set, the memory amount for storing the modulation symbol of each carrier for time interleaving is calculated by (I × mi) for each carrier according to the transmission mode and the length of the time interleaving. Depending on the length of the time interleave, the address value corresponding to the memory amount obtained for each carrier is accumulated in the order of carriers to obtain the accumulated value, and the obtained accumulated value is used as the initial address for each carrier. As a value, incrementing the address number for each OFDM symbol input, reading the symbol stored in the memory from the initial value of the address of each carrier, writing the next input symbol to the address, incrementing the address number, As a result of incrementing the address number, the address number is the address of the memory amount obtained for each carrier. When the upper limit of the value is reached, the address is specified so that the address is returned to the initial value, and it is read from within the area of the memory amount obtained for each carrier according to the transmission mode and the length of the time interleave. It is characterized in that the symbols are time-interleaved outputs.

According to the time interleaving method of the present invention, the symbol buffer size for temporarily storing the modulation symbols of each carrier for time interleaving by (I × mi) for each transmission mode and length of time interleaving. The memory amount corresponding to is calculated for each carrier, and the address value corresponding to the memory amount calculated for each carrier is accumulated in the order of carriers for each transmission mode and the length of time interleave. The calculated value is calculated and used as the initial value of the address for each carrier.
The address number is incremented by 1 every time a DM symbol is input, and the symbol stored in the memory amount area is read from the initial value of the address of each carrier, and the next input symbol is written at the position of the address, and the address number As a result of the increment, when the address number reaches the upper limit value of the address value of the memory area obtained for each carrier, the address is specified to return the address to the initial value, and according to the transmission mode and the length of time interleave, Since the symbols read out from the area of the memory amount obtained for each carrier are the time interleaved output,
The memory size is minimized and the delay time is minimized.

A time deinterleaving method according to the present invention is a time deinterleaving method for performing time deinterleaving by a memory, wherein I is the length of the time interleaving, carrier numbers i sequentially numbered from 0 are 0,
..., nc {(nc = 95 (in transmission mode 1), nc
= 191 (in transmission mode 2) nc = 383 (in transmission mode 3)}, and mi is (ix5) mod96, depending on the transmission mode and the length of the time interleave, {-(Ix mi)} is used to obtain the memory amount for storing the modulation symbols of each carrier for time deinterleaving, and the memory amount obtained for each carrier according to the transmission mode and the time interleaving length. The address value corresponding to is accumulated in the order of carriers to obtain the accumulated value, the obtained accumulated value is used as the initial value of the address for each carrier, the address number is incremented by 1 for each OFDM symbol input, and the The symbol stored in the memory is read from the initial value of the address, the next input symbol is written to the address, and the address number is incremented. When the address number is incremented and the address number reaches the upper limit of the address value of the memory amount obtained for each carrier, the address is specified to return to the initial value, and the transmission mode and time interleave It is characterized in that the symbols read out from the area of the memory amount obtained for each carrier are output as time deinterleaved for each length.

According to the time deinterleaving method of the present invention, as compared with the case of the time interleaving method of the present invention described above, according to the transmission mode and the length of the time interleaving, {-(I × mi)} is used. The amount of memory that corresponds to the amount of symbol buffer that temporarily stores the modulation symbols of each carrier is calculated for time deinterleaving, and operates in the same way as for time interleaving. And the delay time is minimized.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION A time interleaving method according to the present invention will be described below with reference to an embodiment.

FIG. 1 is a schematic block diagram showing a configuration of a time interleaving apparatus 10 to which a time interleaving method according to an embodiment of the present invention is applied.

The time interleaving device according to the present invention comprises a digital signal processor 1 and a time interleaving external memory 6.

The I and Q baseband signals (i-axis data (16 bits) and Q-axis data (16 bits)) before time interleaving are received, temporarily stored in the internal memory 2, and separated from the data before time interleaving. OFD
M symbol interrupt signal, transmission mode information, TMCC (T
ransmission and Multiplexing Configuration Con
control mode information, and stores the transmission mode, TMCC information, and the interleave length in the transmission mode and TMCC information storage memory 3, and based on the transmission mode and the time interleave length, the address data of the time interleave external memory 6 (Also referred to as a pointer) is generated by the address data generation unit 4, data before time interleaving is written in the time interleaving external memory 6 according to the generated address data, and the written data is written from the time interleaving external memory 6 The data is read out and transmitted as data after time interleaving via the internal memory 5.

FIG. 2 shows an external memory 6 for time interleaving.
FIG. 25 is a schematic diagram corresponding to FIG. 25, and the storage capacity is 72960 bytes. In FIG. 2, mi is mi = (i × 5) mod96, and the value of nc is 96.
(Transmission mode 1), 192 (Transmission mode 2), 384
(Transmission mode 3).

3 and 4 are flow charts for explaining the operation of the time interleaving by the time interleaving device 10.

When an OFDM symbol interrupt signal generated for each effective symbol length is input, a time interleave routine is entered, and transmission mode information, time interleave length information, TMCC information such as transmission mode is extracted, and TMCC information is stored. Once stored in the memory 3 (step S1), it is checked whether or not the transmission mode has been identified (step S2). If it is determined that the transmission mode has been identified, it is checked in step S2 whether or not the count value of the counter that counts down the transmission parameter switching index is 0 (step S3).

That is, during the data transmission, the transmission mode 1,
2, 3, length of time interleave 1, 2, 4, 8, 1
When switching to 6, a countdown signal is sent from 15 frames before. This transmission parameter switching index is output for each frame and is counted down by the counter, and when the count value becomes 0, it is determined that the transmission mode or the length of the time interleave is switched.

When it is determined in step S2 that the transmission mode has not been identified, the transmission mode information is identified (step S4). Following step S4, the transmission mode immediately before the arrival of the OFDM symbol interrupt, that is, TM
The transmission mode based on the transmission mode information stored in the CC memory 3 and the transmission mode based on the transmission mode information sent when the next OFDM symbol interrupt comes are compared to determine whether the transmission modes match. Is checked (step S5).

When it is determined in step S5 that the transmission modes match, step S5 is followed by step S5.
3 is executed.

When it is determined in step S3 that the count value of the counter is 0, that is, when it is determined that the transmission mode is switched, or step S3
If it is determined in step 5 that the transmission modes do not match, the length of time interleave is identified (step S
6) It is checked whether the length of the time interleave identified in step S6 matches the length of the time interleave based on the information about the immediately previous time interleave (step S7).

When it is determined in step S7 that the length of the time interleave immediately matches the length of the time interleave, or when it is determined in step S3 that the count value of the counter is not 0 (for example,
(When the number of data segments for each layer, the transmission mode, and the length of time interleaving do not change), the I and Q baseband signals are read from the time interleaving external memory 6 along the previously created Boyne evening ( Step S8).

Subsequent to step S8, the next data is written in the address position of the time interleaving external memory 6 designated by the address data in which the read data was stored (step S9). Step S
9, the address data in the time interleave external memory 6 is incremented by 1 (step S1).
0), it is checked whether the address data in the memory area corresponding to the symbol buffer amount of each carrier in the time interleaving external memory 6 is the upper limit value (step S1).
1).

When it is not determined in step S11 that the upper limit value of the address data of the memory area corresponding to the symbol buffer amount of each carrier is returned, the upper limit of the address data of the memory area corresponding to the symbol buffer amount of each carrier is returned in step S11. When it is determined that the value is the value, the value of the address data is returned to the initial value and the process is returned (step S12).

As described above, data is read from the position based on the address data of the time interleaving external memory 6 based on the address data instruction, and stored in the internal memory 2 at the position corresponding to the read address data. The next data being written is written, the address data of the time interleaving external memory 6 is incremented, and the incremented address data is compared with the initial value of the address of the memory area corresponding to the symbol buffer amount of the next carrier. If they match with each other, the pointer of the carrier is returned to the initial value.

As a result, the written data is read next time after it is stored in the memory area corresponding to the symbol buffer amount, and then when the value of the address data matches the value of the written address data. In particular, time interleaving is performed, and this accumulated number becomes the number of delay symbols after performing time interleaving.

If it is determined in step S5 that the transmission mode information has been changed or that the length of the time interleave has been changed in step S7, new time interleave address data is created and the process is returned (step S6). S13).

When it is determined that the transmission mode has changed and the length of the time interleave has changed, when the step S8 following the next interrupt is executed, reading is performed according to the newly reproduced pointer. .

Next, the time interleaved address data creation in step S13 will be described with reference to the flow chart shown in FIG.

When entering the time interleave address data generation routine, the memory area corresponding to the symbol buffer amount of each carrier of the time interleave external memory 6 is calculated based on the transmission mode, the time interleave length, and the hierarchical transmission method. Performed (step S10)
1). The calculation of the memory area corresponding to the symbol buffer amount of each carrier of the time interleaving external memory 6 is performed for the time interleaving lengths 0, 4, 8, 16 (i
X5) It is performed based on mod96.

The memory area corresponding to the symbol buffer amount of each carrier differs depending on the transmission mode and the time interleave length.

Following step S101, the address is initialized based on the transmission mode and the length of the time interleave (step S102), and then the start address of each data segment is set (step S10).
3) Returned.

However, as a whole, the time interleave length I = 16 in the transmission mode 1 and the time interleave length I = in the transmission mode 2 are
8 and when the time interleave length I = 4 in the transmission mode 3 is the same, the total symbol buffer amount is the same regardless of the transmission mode (FIG. 2).
4).

Here, step S102 will be further described. The symbol buffer amount for each layer is calculated according to the transmission mode and the length I of the time interleave (see FIGS. 27 to 29), and the value obtained by adding the symbol buffer amount for each carrier symbol is set as the initial value of the address data. (See Figures 5-7). 27 to 29, 0 to 95, 0 to 191, and 0 to 383 shown in the left column in the length I of each time interleave indicate the numbers of the sequentially numbered carriers.

For example, when the length I of the time interleave is 16 in the transmission mode 1, the symbol buffer amount is 0 for the first carrier symbol and the symbol buffer amount for the second carrier symbol. 8
It is 0, and the symbol buffer amount is 160 for the third carrier symbol (see FIG. 27A).

Therefore, the initial value of the address data is
0 for the first carrier symbol and the second
80 (= 0 + 80) for the th carrier symbol
And 240 for the third carrier symbol
(= 80 + 160), the initial value of the address data is 0 for the first carrier symbol, and
The initial value of the address data is set to 80 for the third carrier symbol, and the initial value of the address data is set to 240 for the third carrier symbol (FIG. 5).
(See (a)). In FIG. 5, the left column in the length of each interleave shows the number of the assigned carrier.

Next, step S103 will be further described. When the time interleave length differs for each layer, the symbol buffer amount of each data segment differs for each data segment. The value obtained by adding the symbol buffer amount of each data segment in units of this data segment is used as the initial value of the address data of the data segment.

For example, when the time interleave length I = 4 in the transmission mode 1, as shown in FIGS. 5A and 5B, the symbol buffer amount per data segment is 18240, and the time interleave length I = 8
, The number of symbol buffers per data segment is 36480, and the time interleave length I = 1
In the case of 6, the symbol buffer amount per data segment is 72960.

Therefore, in the case of the transmission mode 1, the length I of the time interleave is I = 4, I = 8, I = 16.
The initial value per data segment for the case different from the above will be described. The initial value of the address data of the data segment 0 of the first layer is 0. The initial value of the address data of the data segment 1 of the second layer is 54720 (= 18240 + 36480).
The initial value of the address data of the data segment 3 of the third layer is 127680 (= 54720 + 72960).
Is. In this way, the initial value of the address for the data segment of each layer is obtained.

As described above, one data symbol (1248 (96 × 13) carrier symbols in the case of mode 1, 2496 (192 × 13) carrier symbols in the case of mode 2, and 4992 (384) in the case of mode 3 are obtained. × 1
3) Create address data for the carrier symbol).

Next, returning to FIG. 3, data is read from the time interleaving external memory 6 along the address created in step S8 and stored in the internal memory 5.
At this time, the data for the number of delay symbols required for time interleaving has not yet been accumulated at the beginning, so that the reading state starts from the beginning. 1 for 1 data symbol
After the reading of 248 pieces of data is completed, data is written from the internal memory 2 for one data symbol to the time interleaving external memory 6 by using the same address (step S9). Next, the address is incremented by 1 for each carrier symbol (step S1).
0). Next, it is determined whether or not the upper limit value of the memory area corresponding to the symbol buffer amount for each carrier is reached (step S11).

Here, if the address value of each carrier symbol has not reached the upper limit value, it returns and waits until an OFDM symbol interrupt occurs. If the address value of each carrier symbol reaches the upper limit value, The address is returned to the initial value of the memory area corresponding to the symbol buffer amount for the carrier symbol (step S12). Therefore, the data read in step S8 is accumulated for each carrier symbol in an amount corresponding to the symbol buffer amount, and becomes a delay symbol amount corresponding to time interleaving.

In the case of the transmission mode 2, the length of time interleave is regulated to 1/2 of that in the transmission mode 1, but the number of carriers is twice as large as that in the case of the transmission mode 1. In the transmission mode 3, the length of the time interleave is regulated to 1/4 of that in the transmission mode 1, but the number of carriers is four times that in the transmission mode 1. Therefore, the storage capacity of the time interleaving external memory 6 used for time interleaving does not change regardless of the transmission mode.

The above will be described with reference to a specific example.

The initial value of the address data in the case of the time interleave length I = 16 in the transmission mode 1 is determined from the initial value of FIG. 5 as shown in FIG. 8A, and the address data at the time of the next data symbol. Figure 8
As shown in FIG. 8B, the address data after 80 OFDM symbols is as shown in FIG. 8C.

FIG. 9 shows that in the transmission mode 1, the layer A has a time interleave length I = 16 of 1 data segment, the layer B has a time interleave length I = 8 of 3 data segments, and the layer C has a time interleave length. I =
4 schematically illustrates address data in the case of a hierarchical transmission example of 9 data segments.

FIG. 10 shows the case where the time interleaving length I = 16 in the transmission mode 1 and when the maximum memory capacity is used, that is, when the hierarchies of all 13 data segments have the time interleaving length of 16. The case of an example is shown. In this case, the storage capacity of the time interleaving external memory 6 is 948479 bytes, which is smaller than the conventionally required 1896960 bytes.

The initial value of the address data when the length I of the time interleave is 8 in the transmission mode 2 is determined from the initial value of FIG. 6 as shown in FIG. 11A, and the address data at the time of the next OFDM symbol. Is as shown in FIG. 11 (b), and the address data after 40 OFDM symbols is as shown in FIG. 11 (c). In FIG. 6, the left column in the length of each interleave shows the number of the numbered carrier.

FIG. 12 shows that in the transmission mode 2, the layer A has a time interleave length I = 8 of 1 data segment, the layer B has a time interleave length I = 4 of 3 data segments, and the layer C has a time interleave length. I =
2 schematically illustrates address data in the case of a 13-data segment transmission example in which 2 is a 9-data segment.

The initial value of the address data when the length I of the time interleave is 4 in the transmission mode 3 is determined from the initial value of FIG. 7 as shown in FIG.
The address data for the next OFDM symbol is as shown in FIG. 13 (b), and the address data after 20 OFDM symbols is as shown in FIG. 13 (c). In FIG. 7, the left column in the length of each interleave shows the number of the numbered carrier.

In transmission mode 3, layer A has a time interleave length I = 4 of 1 data segment, layer B has a time interleave length I = 2 of 3 data segments, and layer C has a time interleave length. I =
1 schematically illustrates address data in the case where 1 is a hierarchical transmission example of 9 data segments.

As described above, in the time interleaving apparatus 10, the time interleaving external memory 6 having a storage capacity smaller than that of the conventional symbol buffer is used to perform time interleaving according to any transmission mode or time interleaving length. Will be possible. Further, since the time interleaving is performed by addressing, the delay time can be reduced.

Next, the time deinterleaving method will be described.

Since time deinterleaving is the reverse of time interleaving, only the calculation of the memory area corresponding to the symbol buffer amount of each carrier performed in step S101 differs from the case of time interleaving.

Explaining the case of the transmission mode 1 as an example, when the interleave length I = 16 as shown in FIG. 27A, the carrier number 19 is delayed by the maximum of 1520 symbols and transmitted. In the case of time deinterleave, the carrier number 19 may be set to delay 0. Therefore, the calculation of the storage capacity of the time deinterleaving external memory corresponding to the time interleaving external memory 6 is performed for the time interleaving length I = 0, 4, 8, 16 by using the maximum symbol buffer amount [− {I × (i × 5) mo
d96}].

Based on this, FIG. 15 shows the required storage capacity for each carrier symbol for each time interleaving length I = 4, 8, 16 in the transmission mode 1, and FIG. 17 shows the required storage capacity for each carrier symbol for each of the time interleave lengths I = 2, 4, and 8 in FIG. Indicates the required storage capacity for. 15 to 17,
The left column in the length of each interleave shows the number of the numbered carrier.

Next, in step S102, the initial value of the address data of each data segment is obtained. The method of obtaining the initial value of the address data of each data segment is the same as the method of obtaining the initial value in the case of time interleaving. FIG. 18 shows the initial value of the address data for each carrier symbol for each time I of the time interleave in the transmission mode 1, and FIG. 19 shows the address for each carrier symbol for each length I of the time interleave in the transmission mode 2. FIG. 20 shows the initial value of data, and the initial address value for each carrier symbol for each length I of time interleaving in the case of transmission mode 2. 18 to 20, the left column in the length of each interleave shows the number of the numbered carrier.

For example, in the case of the transmission mode 1, when the time interleaving length I = 16, the address initial value is 0 for the first carrier symbol and the second carrier is as shown in FIG. 1 for symbols
520 (= 0 + 1520), and 2960 (= 1520 + 1440) for the third carrier symbol.

In the case of transmission mode 1, when the time interleave length I = 16, the initial value of the address data is determined from the initial value shown in FIG. 18 as shown in FIG. Sometimes the address data is incremented by 1 as shown in FIG.
After 20 OFDM symbols, the result is as shown in FIG.

FIG. 22 shows that in the transmission mode 1, the layer A has a time interleave length I = 16 of 1 data segment, the layer B has a time interleave length I = 8 of 3 data segments, and the layer C has a time interleave. The length I = 4 of 9 indicates the address data in the case of hierarchical transmission of a total of 13 data segments of 9 data segments.

Further, in the above-mentioned present invention, the case where the stored data is read from the external memory for time deinterleave according to the created address data, the address data is incremented and the data is written in the external memory for time deinterleave has been described. It is also possible to write to the external memory for time deinterleave along with the created address data, then increment the address data and read from the external memory for time deinterleave.

[0079]

As described above, according to the time interleaving method and the time deinterleaving method according to the present invention, the memory scale can be minimized and the processing time of time interleaving and time deinterleaving can be minimized. The effect of being able to do is obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a time interleaving apparatus to which a time interleaving method according to an embodiment of the present invention is applied.

FIG. 2 is a schematic explanatory diagram of an external memory for time interleaving according to the embodiment of the present invention.

FIG. 3 is a flowchart for explaining the operation of time interleaving according to the embodiment of the present invention.

FIG. 4 is a flowchart for explaining the operation of time interleaving according to the embodiment of the present invention.

FIG. 5 is an explanatory diagram of initial value of address data for each carrier for explaining time interleaving of the present invention for each length of time interleaving in the case of transmission mode 1.

FIG. 6 is an explanatory diagram of initial value of address data for each carrier for explaining time interleaving of the present invention for each length of time interleaving in the case of transmission mode 2;

FIG. 7 is an explanatory diagram of initial value of address data for each carrier for explaining time interleaving of the present invention for each length of time interleaving in the case of transmission mode 3;

FIG. 8 is an explanatory diagram of address data used for explaining time interleaving according to the method of the present invention.

FIG. 9 is an explanatory diagram of address data used for explaining time interleaving according to the method of the present invention.

FIG. 10 is an explanatory diagram of address data used for explaining time interleaving according to the method of the present invention.

FIG. 11 is an explanatory diagram of address data used for explaining time interleaving according to the method of the present invention.

FIG. 12 is an explanatory diagram of address data used for explaining time interleaving according to the method of the present invention.

FIG. 13 is an explanatory diagram of address data used for explaining time interleaving according to the method of the present invention.

FIG. 14 is an explanatory diagram of address data used for explaining time interleaving according to the method of the present invention.

FIG. 15 is an explanatory diagram of a storage capacity required for time deinterleaving for each carrier for each length of time interleaving in the case of transmission mode 1 according to the present invention.

FIG. 16 is an explanatory diagram of a storage capacity required for time deinterleaving for each carrier for each length of time interleaving in the case of transmission mode 2 according to the present invention.

FIG. 17 is an explanatory diagram of a storage capacity required for time deinterleaving for each carrier for each length of time interleaving in the case of transmission mode 3 according to the present invention.

FIG. 18 is an explanatory diagram of initial values of address data for each carrier for each length of time deinterleave in the case of transmission mode 1 according to the present invention.

FIG. 19 is an explanatory diagram of initial values of address data for each carrier for each length of time deinterleave in the case of transmission mode 2 according to the present invention.

FIG. 20 is an explanatory diagram of initial values of address data for each carrier for each length of time deinterleave in the case of transmission mode 3 according to the present invention.

FIG. 21 is an explanatory diagram of address data used for explaining time deinterleaving according to the method of the present invention.

FIG. 22 is an explanatory diagram of address data used for explaining time deinterleaving according to the method of the present invention.

FIG. 23 is an explanatory diagram of conventional time interleaving.

FIG. 24 is an explanatory diagram of a maximum symbol buffer amount for conventional time interleaving.

FIG. 25 is an explanatory diagram of a maximum symbol buffer amount for conventional time interleaving.

FIG. 26 is an explanatory diagram of the symbol buffer amount for each carrier in the case of transmission modes 1, 2, and 3.

FIG. 27 is an explanatory diagram of a symbol buffer amount for each carrier in the case of transmission mode 1.

28 is an explanatory diagram of the symbol buffer amount for each carrier in the case of transmission mode 2. FIG.

FIG. 29 is an explanatory diagram of a symbol buffer amount for a customer carrier in the case of transmission mode 3.

[Explanation of symbols]

2 and 5 internal memory 3 Transmission mode, TMCC information storage memory 4 Address data creation section External memory for 6-hour interleaving

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Atsushi Shinoda             1-14-6 Dogenzaka, Shibuya-ku, Tokyo Stocks             Company Kenwood F-term (reference) 5J065 AA02 AB01 AC02 AG06 AH06                       AH09 AH17                 5K014 FA16 HA05 HA10                 5K022 DD01 DD22 DD32                 5K041 BB10 CC07 HH32 JJ28

Claims (2)

[Claims] 1. A time interleaving method for performing time interleaving by a memory, wherein I is a length of the time interleaving, carrier numbers i sequentially numbered from 0 are 0, ..., nc {(nc = 95 (transmission When mode 1), nc = 191 (when transmission mode 2) nc = 383 (when transmission mode 3)}, and mi is (i × 5) mod 96, depending on the transmission mode and the time interleave length. Then, the amount of memory for storing the modulation symbol of each carrier for time interleaving is calculated by (I × mi) for each carrier, and is calculated for each carrier for each transmission mode and time interleaving length. The address value corresponding to the memory amount is accumulated in the order of carriers to obtain the accumulated value, and the obtained accumulated value is used as the initial value of the address for each carrier, The address number is incremented by 1 for each OFDM symbol input, the symbol stored in the memory is read from the initial value of the address of each carrier, the next input symbol is written to the address, the address number is incremented, and the address number is incremented. As a result of the increment, when the address number reaches the upper limit value of the memory value obtained for each carrier, specify the address so that the address is returned to the initial value, and according to the transmission mode and the length of the time interleave,
A time interleave method in which a symbol read out from a region of a memory amount obtained for each carrier is used as a time interleave output. 2. A time deinterleaving method for performing time deinterleaving by a memory, wherein I is the length of time interleaving, carrier numbers i sequentially numbered from 0 are 0, ..., nc {(nc = 95 (In the case of transmission mode 1), nc = 191 (in the case of transmission mode 2) nc = 383 (in the case of transmission mode 3)}, and mi is (i × 5) mod96, the length of the transmission mode and the time interleave According to {-(Ixmi)}
For each carrier, find the amount of memory that stores the modulation symbols of each carrier for time deinterleaving according to, and according to the transmission mode and the length of time interleaving,
The address value corresponding to the memory amount obtained for each carrier is accumulated in the order of the carriers to obtain the accumulated value, and the obtained accumulated value is used as the initial value of the address for each carrier. The number is incremented by 1, the symbol stored in the memory is read from the initial value of the address of each carrier, the next input symbol is written to the address, the address number is incremented, and the result of the increment of the address number is the address number. Address is specified so that the address is returned to the initial value when the upper limit value of the memory value obtained for each carrier is reached, and according to the transmission mode and the length of time interleave,
A time deinterleave method in which the symbols read out from the area of the memory amount obtained for each carrier are output as time deinterleave.