JP2002281082A - Communication equipment and communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately detect the abandonment of a burst cell in communication equipment for processing cells with added sequence numbers denoted by N (N is natural number) as modulo and frame leading display by every M (M is natural number times as large as N). SOLUTION: A sequence number protecting means generates the number of abandoned cells or decided sequence numbers for protecting sequence numbers from frame leading display and sequence numbers extracted from a received cell input 100 by a sequence number field extracting means 101, and a cell outputting means 103 outputs dummy cells for the number of abandoned cells, or outputs normal cells by adding the decided sequence numbers to them. A sequence number protecting means 102 detects the number of abandoned cells which is not more than N-1 from the sequence numbers, and detects the number of abandoned cells which is not less than N from the frame leading display.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a communication terminal,
The present invention relates to a communication method and a communication device that perform communication using a plurality of communication packets as a processing unit.

In particular, the present invention relates to a communication method and a communication apparatus for performing interleaving and error correction processing with a plurality of packets as processing units.

[0003]

2. Description of the Related Art As a conventional technique for transmitting data after performing error correction on a high-speed communication network, there is a method of performing error correction on an adaptation layer which is an upper layer of ATM, for example. For example, in the ATM adaptation layer type 1 (hereinafter, referred to as AAL1) defined in ITU-T I363.1, error correction is performed on transmission data using a long interleaver matrix.

FIG. 11 is a schematic diagram of a transmission method using a long interleaver matrix. On the transmitting side, the transmission data is divided into 124 bytes each, and a 4-byte forward error correction code (hereinafter referred to as FEC: Forwa
rd Error Correction) and write direction 100
1 is written in the row direction, and this procedure is repeated 47 times to generate a long interleaver matrix composed of 128 × 47 transmission data. The reading is performed sequentially in 47-byte units in the column direction indicated by the reading direction 1002, and the read transmission data (SAR-PDU of 47 bytes) is read.
A 1-byte header (SAR-PDU header) including a sequence number and the like is added to the payload (payload), and 4 bytes of an effective data transmission portion (hereinafter, referred to as a payload) in the ATM cell are added.
The data is transmitted as ATM cells by adding 8 bytes and further adding an ATM header of 5 bytes. The receiving side performs the reverse operation to extract the transmission data.

FIG. 12 is a configuration diagram of an ATM cell. Figure 1
As shown in Fig. 2, SAR-PDU (segmentation and reassembl
y protocol data unit) The header is divided into an SN field and an SNP field. The SN field is further divided into a CSI bit and a sequence count field (SC).
SC is 3 bits, and values from 0 to 7 are sequentially assigned in the reading order of the long interleaver matrix (sequence number). Further, the CSI bit is set to 1 at the beginning of reading of the long interleaver matrix, and is set to 0 otherwise.
To display the head of the long interleaver matrix (frame head display). That is, CSI is 1 and SC is 0 at the head of the long interleaver matrix.

FIG. 13 shows a sequence count (S
It is a schematic diagram which shows the provision order of C). Each number indicates one cell. The SC repeats the sequence of 0 to 7 16 times to form a long interleaver matrix (portion surrounded by a large frame in the figure). As described above, the head cell of the long interleaver matrix has SC of 0 and CSI bit of 1 (SC = 0 in the circle in the drawing). The SNP field is a parity for performing error correction on the SN field, and a 3-bit CRC is used for the SN field.
Field and 1-bit even parity for CSI bits, SC and CRC fields.

The receiving terminal reconstructs a long interleaver matrix based on the SAR-PDU header.
In the TM network, cell discards and uncorrectable bit errors occur, and SCs are not always received continuously. Further, there is no guarantee that the head cell of the long interleaver matrix is received in all the long interleaver matrices. Therefore, generally, the SN field is protected by using the characteristic that SC is sequential from 0 to 7.

Examples of the protection of the SN field include, for example, JP-A-5-37549, JP-A-6-31175, and JP-A-5-136817.
These technologies predict the SC of the next received cell from the SAR-PDU information of the received cell and protect the SC, or temporarily hold the received cell and save the cells before and after the cell. To protect the SC of the cell. further
The number of cell discards is calculated simultaneously with SC protection.

[0009]

However, in the above-mentioned conventional configuration, SC takes only a value from 0 to 7. Although it is effective for discarding seven or less cells, there is a problem that when eight or more cells are discarded, the processing is performed as discarding seven or less cells. In other words, there is a problem that cell discards exceeding the number of SC sequences cannot be detected. If the number of cell discards is wrong, for example, in the case of transmission of a video or the like, there is a problem that the video in the upper layer of AAL1 is out of synchronization and the video is broken.

When the synchronization between the transmitting and receiving terminals is performed by the adaptive clock method defined in ITU-T I363.1, the adaptive clock method allows the receiving terminal to transmit to the transmitting terminal based on a change in the amount of received data. Since it is a method of determining whether the communication is late or early and synchronizing with the transmitting terminal by a PLL or the like, if erroneous detection of the number of discarded cells occurs, there is a problem that synchronization between the transmitting and receiving terminals cannot be guaranteed.

FIG. 13 is a schematic diagram of cell discarding. FIG.
In, a cell discarded portion is surrounded by a square, and SC is assigned to each cell. The large squares each indicate a long interleaver matrix composed of 128 cells. The above conventional problem will be described with reference to FIG. In FIG. 13, when the cell column 1201 is discarded, the SC jumps from 1 to 7. Therefore, it is determined that five cells have been discarded. Similarly, in the case of the cell row 1203, three cells are discarded because the SC flies from 6 to 2, and in the case of the cell row 1205, seven cells are discarded because the SC flies from 4 to 4, and in the case of the cell 1207. Determines that one cell is discarded because the SC is flying from 4 to 6.

However, in the case of the cell row 1202, 1
In spite of one cell being discarded, since the SC jumps from 5 to 1, it must be determined that three cells are discarded. That is, in the case of discarding eight or more cells, an error occurs in the number of cell discards in multiples of eight. Therefore, in the next long interleaver matrix, cell 1
204, the next time, since the SI bit is detected in the cell 1206 and the protection of the head display of the long interleaver matrix is applied, the received cell is not written in the correct position of the long interleaver matrix. In addition, the data position is not accurate, and the data amount of the stream in the upper layer is partially shortened, the synchronization is lost, and the communication quality is significantly deteriorated. In particular, in the case of transmission of images, sounds, and the like, problems occur such that long-term received data is not normal and images and sounds are broken.

As a method of detecting discard of eight or more cells, a method of detecting a discard of the SAR-PDU header by changing the SAR-PDU header portion to a method not based on ITU-T I363.1, for example, by increasing the number of SC bits, is also available. However, if such a method is used, there is a problem that a general-purpose communication terminal compliant with ITU-T I363.1 cannot be used. In addition, since the number of SNP fields is reduced, there is a problem that the correction capability of the SN field is reduced.

A method of storing received cells in a buffer memory or the like for a long period of time and analyzing the information of the SAR-PDU for a long period by using a microcomputer or the like and detecting discard of eight or more cells can be considered. However, this method increases the delay by storing data in the buffer memory for a long period of time.
There has been a problem in the transmission of applications that require transmission with low delay, such as voice. Further, there is a problem that a microcomputer, a large-scale circuit, a large-scale buffer memory, and the like are required.

From the above, in a communication apparatus that processes a communication packet to which a sequence number is added, the number of cell discards is accurately detected even when packet discard (cell discard) exceeding the sequence range of the sequence number occurs. Is required.

In view of the above, it is an object of the first invention of the present application to provide a communication device capable of accurately detecting the number of cell discards with a low delay and a simple configuration.

The second invention of the present application solves the following problem. In the method using the long interleaver matrix as described above, transmission becomes possible when the processing of the long interleaver matrix is completed. In other words, communication cannot be performed unless 5828 (124 × 47) bytes of data are input. Generally, there is no correlation between the data amount of the layer of the long interleaver matrix and the data amount of the upper layer, and the long interleaver matrix processing of the final part of the data of the upper layer is not completed at the end of communication, and the final part of the data is not completed. Is missing and data is missing.

In view of the above problems, it is an object of the present invention to provide an apparatus capable of transmitting data of an upper layer to the end even if the data amount of a layer such as a long interleaver matrix and the upper layer has no correlation. I do.

[0019]

In order to solve the above-mentioned problems, according to the communication apparatus of the present invention, the sequence number protection means determines the number of cells to be discarded or the sequence number based on the sequence head number and the sequence number extracted by the sequence number field extraction means. Generate a confirmed sequence number that protects the number,
The cell output means generates dummy cells for the number of discarded cells or adds a determined sequence number to the cells and outputs the cells.

Further, in the communication apparatus according to the present invention, the dummy cell generation means generates dummy cells for the data amount less than the transmission processing unit, and the transmission cell generation means generates and outputs a transmission processing unit using the transmission data and the dummy cell. .

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The first invention of the present invention relates to a communication system in which a sequence number modulo N (N is a natural number) and a frame head indication is added every M (M is a natural number times N). A communication device for communicating a packet, wherein a sequence number field extracting means for extracting the frame head display and the sequence number from the communication packet, and the frame head display and the sequence number extracted by the sequence number extracting means, Sequence number protection means for calculating the number of communication packet discards and generating a confirmed sequence number that protects the sequence number; generating dummy communication packets for the number of communication packet discards calculated by the sequence number protection means; and Communication packet output means for adding a number to the communication packet and outputting the communication packet; A communication device, wherein the sequence number protection means detects the number of discarded communication packets of N-1 or less from the sequence number, and detects the number of discarded communication packets of N or more from the frame head display. The sequence number protection means detects the number of discarded communication packets or protects the sequence number, and the packet output means generates dummy communication packet cells for the number of discarded cells or adds the protected sequence number to the received cells. Therefore, even when the communication cells are continuously discarded in a burst manner, the received data can be quickly normalized.

Further, according to a second aspect of the present invention, a plurality of communication packets having a predetermined length P (P is a natural number)
(M = P × J: J is an integer of 2 or more) a communication device that performs transmission processing, generates transmission data, and outputs a transmission end signal when the generation is completed;
Transmission communication packet means for generating a transmission communication packet from the transmission data; and a data amount Q of the transmission communication packet generated by the transmission communication packet generation means when the transmission end signal is received from the transmission data generation means. When Q is less than the transmission processing unit M, dummy data having at least a data amount (M−Q) is generated and output to the transmission data generation means. Is a predetermined data amount M from the transmission data output from the transmission data generation means and the dummy data output from the dummy data generation means.
Wherein the dummy data generation means generates dummy cells by a data amount less than a transmission processing unit, and the transmission cell generation means performs transmission processing by the transmission data and the dummy cells. Since the unit is generated and output, even if there is no correlation between the data amount of the upper application and the transmission processing unit, the data of the application can be transmitted to the end.

(Embodiment 1) Embodiment 1 will be described by taking as an example a case where a long interleaver matrix method is used. Therefore, in the first embodiment, N
A sequence number modulo (N is a natural number) is N = 8
(0, 1, 2, 3, 4, 5, 6, 7). Also M
(M is a natural number multiple of N) M = 1
28, the frame head indication is indicated by the CSI bit and SC.

FIG. 1 shows a configuration diagram of a communication device according to the first embodiment of the present invention.

In FIG. 1, reference numeral 100 denotes a reception cell input, 1
01 is a sequence number field extracting means for correcting the SAR-PDU header of the received cell input 100, and 102 is the CS corrected by the sequence number field extracting means 101.
Sequence number protection means for determining SC and calculating the number of communication packet discards (cell discards) from I bit and SC,
A cell output means 103 is a communication packet output means for generating a received cell output 104 by outputting a fixed SC output from the sequence number protection means 102 and replacing SCs of cells based on the number of cell discards and outputting dummy cells corresponding to the number of cell discards. It is.

Sequence number field extracting means 101
Corrects the SAR-PDU header of the received cell input 100.
That is, the CSI bit and the sequence count field (SC) are corrected using the CRC field and the even parity bits in the SNP field. The corrected CSI bit and SC are input to the sequence number protection means 102. The SAR-PDU payload is input to the cell output means 103. If the sequence numbers are not consecutive, the sequence number protection means 102 determines that cell discard has occurred and calculates the number of cell discards.

FIG. 2 is a flowchart showing a method of calculating the number of cell discards in the sequence protection means 102. FIG. 3 is a schematic diagram of cell discard detection. FIG. 3 shows a schematic diagram of the cell on the time axis. The upper row of the cell shows the SC after correction, and the lower row shows the determined SC and the number of cell discards. FIG. 3 shows cells before and after 1201 in FIG. 13 as an example of cell discarding, and black cells are discarded cells.

The method of calculating the number of discarded cells will be described below with reference to FIGS.

Sequence number field extracting means 101
After the corrected SC is 6, 7, 0, and 1, 7 is input to the sequence number protection means 102. First, 6 is set as the sequence number R of the previously received cell, and 7 is set as the sequence number S of the next received cell (steps 201 and 202 in FIG. 2). Since R and S are continuous numbers, the sequence number protection means 102 outputs R = 6 as a fixed SC, 7 is R for R, and the next SC is R for R.
0 is set (steps 204 and 205). Similarly,
7,0,1 SC has continuity, so each is confirmed SC
Is output as On the other hand, the portion skipping from 1 to 7 is R = 1, S = 7, and R <S, so that the number of cell discards is SR-1 = 7-1-1 = 5, which is 5 Is notified that the cell discard has occurred and the cell discard number is 5 (steps 206 to 208). SC = cell loss
7 is inputted, the number of discarded cells = 5 becomes SC = 7
Is output before. In the case of 1203 in FIG. 13, the SC after correction is input as 6 or 2 from the sequence number field extracting means 101. In this case, since SC = 6 has continuity with the previous SC = 6, it is output as the determined SC. R = 6, S =
In the case of 2, R> S, and the number of cell discards = N−R + S−
1 = 8−6 + 2-1 = 3, and the number of cell discards becomes three (step 209, step 210 in FIG. 2). The cell discard occurrence is determined when SC = 2 is input, and the number of cell discards = 3
Is output before SC = 2 (step 208). further,
In the case of 1205 in FIG. 13, the corrected SC is input as 4 or 4 from the sequence number field extracting means 101.
In this case, R = S, and the number of cell discards = N-1 = 8-1
= 7 (step 211 in FIG. 2). As described above, the processing is first performed assuming that seven or less cells are discarded.

Note that the sequence number protection means 102
Also protects. For example, when the correction SC is input in the order of 2, 3, 7, and 5, it is determined that SC = 7 is incorrectly corrected or cannot be corrected, and SC = 4 is corrected (not shown). Such a discontinuity occurs due to, for example, an erroneous correction of the SAR-PDU header or an uncorrectable bit error. The cell output means 103 changes the SC of the cell when the fixed SC is input, and outputs the dummy cells for the number of cell discards when the number of cell discards is input.
04 is output.

Next, the processing of the sequence number protection means 102 when eight or more cells are discarded will be described. When eight or more cells are discarded, the number of cell discards is detected using the frame head indication (CSI). In the case of a long interleaver matrix, the frame head display is detected every 128 cells.

FIG. 4 is a state transition diagram of frame head display protection. This process is performed by the sequence number protection means 102. The sequence number protection means 102 makes a state transition between the search state, the synchronization detection state, the synchronization state, and the out-of-synchronization state. The initial state is a search state.

When the frame head display is detected in the search state, the state transits to the synchronization detection state (300 in FIG. 4),
If a frame head display is not detected at an interval of 128 cells in the synchronization detection state, the state transits to the search state (301).
If a frame head display is detected at a 128-cell interval in the synchronization detection state, a transition is made to a synchronization state at a 128-cell interval (phase) (302), and a frame head display is detected at a 128-cell interval in the synchronization state. In this case, the frame remains in the synchronized state (303). If the display of the top of the frame is not detected at the interval of 128 cells in the synchronized state, the state transits to the out-of-synchronization state (304). When the display is detected, the state transits to the synchronous state (3
05), when the frame head display is not detected at an interval of 128 cells in the out-of-synchronization state, if the number of frame protections is within a predetermined number of times, the protection processing of the frame head is performed and the out-of-synchronization state is maintained (306). If the number of times exceeds the number, the state transits to the search state (307). If the frame head display is detected at an interval of 128 cells at another phase in the out-of-synchronization state, the state transits to the synchronous state at the phase and the synchronous state is reached. The number of cells corresponding to the difference between the phase and the phase detected due to the loss of synchronization is processed as the number of cell discards (3
08).

In FIG. 4, when 128 or less cells are discarded in the long interleaver matrix at intervals of 128 cells, the number of discarded cells is counted. Therefore, the operation of FIG. 3 performs a so-called flywheel operation by detecting the display of the top of the frame. A characteristic feature of the first and second aspects of the present invention is a cell discarding process at the state transition 308.

FIG. 5 is a schematic diagram showing the sequence count (SC) and burst cell discard (in the case of a long interleaver matrix, discarding eight or more cells). In FIG. 5, each number is SC of each cell, and the number sequence surrounded by a large frame is 128.
Cells 403, 404, 405, and 406 indicate the first cell of the frame. FIG. 4 shows a case where 11 burst cells are discarded in the cell row 400 (40).
0 is the same as 1202 in FIG. 13).

FIG. 6 is a schematic diagram showing the processing of the sequence number protection means 102 when a burst cell is discarded. FIG.
Shows cells near the cell row 400. Since the corrected SC of the normally received cell jumps from 5 to 1, the sequence number protection means 102 determines that three cells have been discarded, and immediately before the cell (SC = 1) immediately after the burst cell discard. And the cell output means 103 is notified. Burst cell discard in cell row 400 is actually 1
Since one is generated, eight cells are not detected.

Since the sequence number protection means 102 detects the head of the frame at an interval of 128 cells (first phase) in the cells 403 and 404 of SC = 0 or the cells before it, they are already in the synchronized state ( 3 in FIG.
03). Since the discard of eight cells has not been detected in the cell row 400, the sequence number protection unit 102 detects that the cell 401 after 128 cells has the frame head display. Therefore, the state immediately shifts to the out-of-synchronization state (30 in FIG. 4).
4).

Next, the sequence number protection means 102 detects a frame head display at an interval of 128 cells between the cells 405 and 406. This cell 405 and cell 40
The phase (first phase) of the detection of the frame head display at the 128-cell interval of No. 6 is normal in the synchronized state by the sequence number protection means 102 due to the non-discard detection of eight cells. The phase is different from the phase (second phase) of the cell 401 and the cell 402 (here, 402 is not received when 406 is detected). Therefore, the sequence number protection means 102 immediately determines that the phase at 405 and 406 is the correct phase of the frame head display detection, and shifts to the synchronous state at the phase (308 in FIG. 4). At the same time, the sequence number protection means 102 performs a process of discarding an undetected cell at the time of the state transition at 308 in FIG. In FIG. 5, the state transition is made in the cell 401 to the out-of-synchronization state, and the state transition is made from the out-of-synchronization state to the synchronization state by detecting the cell head display of the cells 405 and 406. At this time, the cell 405 becomes the cell 40
1 is input earlier in time, but a counter for detecting a cell head display at 128-cell intervals to make a state transition from an out-of-synchronization state to a synchronization state is provided when a cell head display other than the synchronization state is detected. It can be realized by operating. In other words, the reception of the cell head display of the cell 405 is processed as being out of synchronization at this time due to the burst cell discarding in the cell row 400, so that the counter operates, and the cell head display of 406 after 128 cells is detected. To a normal synchronization state.

FIG. 7 is a schematic diagram of the undetected cell discarding process. FIG. 7 shows a cell near the cell 406 in FIG.
Since the frame head display is detected at a normal phase when the cell head display of the cell 406 is detected, the sequence number protection unit 102 sets the cell discard number 8 immediately before the cell 406 (SC = 0).
Is displayed and the cell output means 103 is notified. Cell 406
, The sequence number protection means 102 makes a state transition from an out-of-synchronization state to a synchronization state (308 in FIG. 4).

The calculation of the number of undetected cell discards can be performed with a simple configuration by the following procedure as an example. The sequence number protection means 102 is provided with a counter starting from the cell head display to measure 128 intervals. The counter is reset to 0 since the cell head display was detected in the cell 405, and the value of the counter in the cell 406 is 120 (second phase) because eight cells have not been discarded. Therefore, 8 which is a difference from 128 (first phase) is the number of undetected cell discards. In this method, it is needless to say that calculation is possible even with the number of undetected numbers other than 8.
This counter also adds the number of discarded cells when detecting seven or less cell discards in the long interleaver matrix.

FIG. 8 is a schematic diagram of frame head protection.
In FIG. 8, reference numeral 700 denotes 701 when the present invention is not used.
Shows the case where the present invention is used. The protection of the head of the frame will be described in more detail with reference to FIG. 8, and the effect unique to the present invention will be described by comparing the operation with the case of using the conventional technology. It should be noted that FIG.
And the phrases and symbols set forth in FIG.

At 700, a burst cell is discarded in the cell row 400, and the number of cell discards is set to 3 to insert a dummy cell. Here, since eight cells are not detected as the number of discarded cells, the head of the frame is protected at 401 and the state shifts to an out-of-synchronization state. Thereafter, the head of the frame is protected at a wrong position such as 402. The normal frame head protection is performed again after the number of frame protections is exceeded, the state shifts to the search state, and the state shifts to the synchronization state after the synchronization detection state. During this period, the reception cell cannot be restored to a normal position in the long interleaver matrix as indicated by 702, and the reception data is in an abnormal state for a long time.

At 701, the synchronization is similarly lost from 401, but 405 (not shown in FIG. 8) and cell 4
In step 06, a normal frame head display is detected, so that the synchronous state is restored with the correct phase. At this time, immediately before the cell 406, the normal cell number is guaranteed by processing the eight cell discards not detected in the cell row 400 as the cell discard number.

The cells 406 and thereafter are in a synchronized state and data can be normally received. At 701, the portion shown at 703 becomes invalid data, but it is clear that the number of invalid data portions is smaller than at 702. Therefore, even when burst cells are discarded, the received data can be normalized at an early stage, and high quality communication can be provided.

In particular, in the case of image transmission, for example, processing data in a video frame period for processing video synchronization is larger than the processing unit of the long interleaver matrix, and the number of data is normally processed in the layer of the long interleaver matrix. As a result, the synchronization of the image processing in the upper layer is not lost, so that the effects of the first and second aspects of the present invention are particularly large.

In the case of voice transmission, a unit smaller than the long interleaver matrix, for example, ITU-T I36
In the short interleaver matrix specified in 3.1, the unit of the matrix is 94 × 8 bytes (of which the payload is 88 × 8 bytes) or the like, which is smaller than the unit for synchronizing the voice transmission which is the upper layer. Since it is small, the number of data is normally processed in the lower layer, so that the synchronization of image processing in the upper layer does not get out of sync. Therefore, the effects of the first and second aspects of the present invention are particularly large.

When synchronizing between transmission and reception is established by the adaptive clock method, it is important to make the data amount between transmission and reception exactly the same. Can be detected, and high-quality transmission in which synchronization between transmission and reception is established becomes possible. In particular, in the case of image / audio transmission, high-quality transmission without image skipping or audio noise can be achieved.

Further, the processing delay in the present invention is such that the sequence number protection means 102 determines that the cell is discarded by one.
In the cell output means 103, only a delay of about several cells required for temporarily holding a normal cell for waiting after completion of dummy cell insertion due to cell discarding is provided. Therefore, low-delay transmission is possible, which is effective for transmission of applications that require strict delays for images and sounds.

It goes without saying that the present invention can be realized by a simple circuit such as a counter and a subtractor.

In this embodiment, the case where the number of burst cell discards is 11 is taken as an example. However, regardless of this number, one is subtracted from the frame head display interval of 128.
Needless to say, this is effective for discarding 127 or less burst cells. The present invention is also effective when the frame display is other than 128 intervals, and such a case is not excluded from the scope of the present invention.

The sequence count (SC) is not limited to 0 to 7, and other ranges are not excluded from the scope of the present invention.

In the embodiment of the present invention, the sequence number field extracting means 101 corrects errors in the sequence number (SC) and the frame display CSI. However, this error correction is not essential to the present invention. In addition, even when error correction is not performed, this does not exclude the scope of the present invention.

The error correction shown in FIG. 11 is not an essential component of the present invention, and the case where error correction is not performed is not excluded from the scope of the present invention.

In this embodiment, a long interleaver matrix has been described as an example. However, a sequence number modulo N (N is a natural number) and a frame head for each M (M is a natural number multiple of N) are used. If the processing of the communication packet to which the display is added is performed, the present invention is not limited to this and has the effects of the present invention, and is not excluded from the scope of the present invention.

Although the case where N = 8 and M = 128 has been described as an example, the present invention is not limited to this.

(Embodiment 2) FIG. 9 is a configuration diagram of a communication apparatus according to the present embodiment.

In FIG. 9, reference numeral 800 denotes a transmission data generation means for continuously generating transmission data, and a transmission end signal 803 for notifying the transmission data at the end of transmission. Reference numeral 801 denotes a long interleaver for the transmission data output from the transmission data generation means 800. The transmission cell generation means for processing the matrix and outputting a transmission cell 804 of a predetermined length P (P is a natural number). When a transmission end signal 803 is received from the transmission data generation means 800, the transmission cell generation means 802 This is dummy data generation means for generating dummy data to be used when the leaver matrix processing has not been completed.

The transmission data generation means 800 continuously generates transmission data, and outputs a transmission end signal 803 to the transmission cell generation means 801 and the dummy cell generation means 802 at the end of transmission. This transmission data generation means 800 may not be integrated with the configuration of FIG. 9 and may be an external input. The transmission cell generation means 801 performs the processing of the long interleaver matrix shown in FIG.
A cell payload of 47 bytes is generated as the transmission cell 804 of bytes (P = 47).

After receiving the transmission end signal 803 from the transmission data generation unit 800, the dummy data generation unit 802 generates dummy data to be used when the long interleaver matrix processing of the transmission cell generation unit 801 is not completed. That is, the transmission processing unit M of the long interleaver matrix is P = 47 and J = 124 from FIG.
Therefore, M = P × J = 47 × 124 = 5828
Transmission is possible in bytes. Dummy data generating means 8
02 indicates that the data amount Q input to the transmission cell generation means 801 at the time of receiving the transmission end signal 803 is the transmission processing unit M
If Q is less than (M <M), at least dummy data is input from the dummy data generating means 802 as the data amount (M−Q), and the transmission cell generating means 801 sets the predetermined data amount M as a long interleaver. The matrix processing is completed and the transmission cell 804 is output. Here, FIG.
Is generated in the transmission cell generation means 801.

FIG. 10 is a schematic diagram showing the long interleaver matrix processing at the end of transmission. In FIG. 10, the transmission ends at 903, and the transmission data generation unit 80
Input of transmission data from 0 ends. In this case, the transmission data transmitted from the transmission data generation means 800 is 904
(Data amount Q). In this state, the final long interleaver matrix processing is not completed and transmission cannot be performed. Therefore, the dummy data generated by the dummy data generating means 802 is inserted into a portion 905 (data amount MQ) after 903, and the long interleaver matrix processing is performed. By generating a transmission cell by completing the leaver matrix, it is possible to transmit even the final data and achieve high quality communication.

Next, a specific description will be given by taking the case of image transmission as an example. In the case of image transmission, for example, transmission is performed in video frame units, but the data amount of the video frame is independent of the processing unit of the long interleaver matrix. Therefore, the last data part of the last frame is shown in FIG.
In most cases, the state shown in FIG.

Here, if the final long interleaver matrix is not transmitted, some data of the final video frame is lost and the image is broken. However, according to the third aspect of the present invention, since the last frame is transmitted, image communication that guarantees high image quality without image breakdown can be performed.

A more preferable example will be described. 90 in FIG.
Data of the third and subsequent data is transmitted in units of two images, that is, in this case, data of the same image of two video frames is transmitted. For example, an image of an image in which the entire screen is black (hereinafter, referred to as all black) is transmitted in two frames. That is, from the time when the transmission data generation unit 800 generates the transmission end signal 803, the dummy data generation unit 802 inputs two frames of all-black data to the transmission cell generation unit 801. In this case, the first frame of all black is transmitted from 903 using a long interleaver matrix.
At this time, if the data of the last part of the first frame of the all black is not completed in units of the long interleaver matrix, the head data of the second frame of the all black is processed and transmitted together with the same long interleaver matrix. You. Here, the data of the final portion of the second frame of the all black may not be transmitted because the long interleaver matrix is not completed. At this time, on the receiving side, the all-black portion of the first frame has been completely received. Therefore, the last untransmitted portion of the second frame is completely replaced by replacing the previous frame, that is, performing error correction with the data of the first frame. It becomes all black. The image is fixed (frozen) on the receiving side even after communication is completed in this all-black mode.

As described above, according to the third aspect of the present invention, the data of the last frame can be completely communicated, and when the communication is completed, the data can be ended on a fixed screen such as all black, so that a high quality image can be obtained. Communication is possible.

In the above example, the image unit is a video frame. However, for example, a video field or MPEG G
Any unit may be used as long as the process is based on an image unit such as an OP unit. Further, a processing unit such as audio may be used.

Although the long interleaver matrix is exemplified as the transmission processing unit, other transmission units are not excluded from the scope of the present invention.

In the case of voice transmission, by transmitting silent data as dummy data at the end of transmission, high-quality transmission without noise is possible.

In this embodiment, all black is used as an example, but other images such as color bars are not excluded from the scope of the present invention.

In this embodiment, P = 47 and J =
124, M = 5828 bytes has been described as an example, but the present invention is not limited to this.

In the first and second embodiments, the ATM communication is used as an example together with the long interleaver matrix. However, other packet communication is not excluded from the scope of the present invention.

[0071]

As described above, according to the present invention, it is possible to normalize received data at an early stage with a simple configuration even when communication packets are continuously discarded in a burst manner, and high quality communication can be achieved. A device and a communication system can be provided.

In particular, in the case of image transmission, since the number of data is processed normally, the synchronization of image processing in the upper layer is not lost.

Further, when synchronization between transmission and reception is established based on the amount of received data such as an adaptive clock method, the amount of data between transmission and reception can be made exactly the same.
High quality transmission in which synchronization between transmission and reception is guaranteed is possible.
In particular, in the case of image / audio transmission, high-quality transmission without image skipping or audio noise can be achieved.

Further, according to the present invention, cell holding at the receiving terminal is short, and low-delay transmission is possible. This is effective for transmission of applications that require strict delays for images and sounds.

Further, even when there is no correlation between the data amount of the upper-level application and the transmission processing unit, high-quality transmission that can transmit the application data to the end can be performed. In particular, in the transmission of images and sounds, it is possible to obtain an effect that high-quality transmission without image disturbance, sound noise, and the like can be performed even after the end of communication.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a communication device according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing an operation of a sequence number protection unit.

FIG. 3 is a schematic diagram of cell discard detection.

FIG. 4 is a state transition diagram of frame head display protection.

FIG. 5 is a schematic diagram showing sequence count and burst cell discarding.

FIG. 6 is a schematic diagram showing processing of a sequence number protection unit when a burst cell is discarded;

FIG. 7 is a schematic diagram of an undetected cell discarding process.

FIG. 8 is a schematic diagram of frame head protection.

FIG. 9 is a configuration diagram of a communication device according to a second embodiment of the present invention.

FIG. 10 is a schematic diagram showing long interleaver matrix processing at the end of transmission.

FIG. 11 is a schematic diagram of a transmission method using a long interleaver matrix.

FIG. 12 is a configuration diagram of an ATM cell;

FIG. 13 is a schematic diagram showing a sequence count application sequence.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 reception cell input 101 sequence number field extraction means 102 sequence number protection means 103 cell output means 104 reception cell output 800 transmission data generation means 801 transmission cell generation means 802 dummy data generation means

 ──────────────────────────────────────────────────の Continuing from the front page (72) Inventor ▲ Hama ▼ Shinji I. 1006 Kadoma Kadoma, Kadoma City, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. F term in the company (reference) 5K030 GA11 HA10 HB02 HB15 HB29 JA06 LA01 LA15 MB12 MB13 5K034 EE11 MM01

Claims (13)

[Claims] 1. A communication device for communicating a communication packet to which a frame number display is added for each sequence number modulo N (N is a natural number) and for each M (M is a natural number multiple of N), A sequence number field extracting means for extracting the frame head display and the sequence number from the communication packet; and calculating the communication packet discard number and the sequence number from the frame head display and the sequence number extracted by the sequence number extracting means. Sequence number protection means for generating a protected confirmed sequence number, generation of dummy communication packets for the number of discarded communication packets calculated by the sequence number protection means, and addition of the confirmed sequence number to the communication packet for output Communication packet output means, said sequence number protection The communication device, wherein the means detects the number of discarded communication packets of N-1 or less from the sequence number, and detects the number of discarded communication packets of N or more from the frame head display. 2. The sequence number protection means continuously receives a communication packet with a sequence number R and a communication packet with a sequence number S (R and S are natural numbers equal to or less than N).
If S is not continuous modulo N and R> S, the number of cell discards is (N−R + S−1), and R and S are N
Is not continuous modulo R, and R <S, the cell discard number is (S−R−1). If R and S are not consecutive modulo N and R = S, the number of communication packet discards is To (N-
1), and furthermore, a state in which a frame head display is detected continuously at M communication packet intervals (phases) is defined as a first phase synchronization state. When the frame head display is not detected at a communication packet interval and the frame head display is detected at an interval of M cells in a second phase state different from the synchronization state of the first phase, 2. The communication device according to claim 1, wherein a synchronization state is established at a phase of (i), and a difference between the first phase and the second phase is a communication packet discard number. 3. A sequence number protection unit, in a search state in which a frame head display is detected from an input communication packet, transitions to a synchronization detection state when the frame head display is detected, and in the synchronization detection state, , M
When the frame head display is not detected at a communication packet interval (hereinafter, referred to as a phase), the state transits to the search state. When the frame head display is detected at the phase, the state transits to the synchronization state at the phase. In the synchronous state,
When the frame head display is detected in the phase, the frame remains in the synchronization state, and when the frame head display is not detected in the phase, the frame shifts to an out-of-synchronization state. If a display is detected, the state shifts to the synchronization state.If the frame head display is not detected in the phase, the frame head display protection processing is performed and the synchronization stop state is maintained within a predetermined number of protections. When the number of protections exceeds a predetermined number, the state transits to the search state, and in the out-of-synchronization state, when the frame head display is detected in the phase when the phase is different from the phase, the state is synchronized in the phase With the transition, the number of communication packets corresponding to the difference between the phase in the synchronous state and the phase detected in the out-of-sync state is calculated. Communication device according to claim 1, wherein characterized in that output as signal packet discards. 4. The communication device according to claim 1, wherein the sequence number field extracting means performs display of a frame head and correction of the sequence number. 5. A communication method for cells in which a frame number is added to each of M (M is a natural number multiple of N) sequence numbers modulo N (N is a natural number) and N-1 A communication method, wherein the following cell discard number is detected from the sequence number, and N or more cell discard numbers are detected from the frame head display, and dummy cells for the cell discard number are generated. 6. A communication packet having a sequence number R and a communication packet having a sequence number S (R and S are natural numbers equal to or less than N) are continuously received, and R and S are not continuous modulo N and R> If S, the cell discard number is set to (N−R +
S-1), and when R and S are not continuous modulo N and R <S, the number of cell discards is (S-R-1),
If R and S are not continuous modulo N and R = S, the number of communication packet discards is set to (N-1), and the start of frame is detected continuously at M communication packet intervals (phases). The state in which the first frame is present is defined as a first phase synchronization state. In the first phase synchronization state, the frame head indication is not detected at intervals of M communication packets and the second phase differs from the first phase synchronization state. When the frame head display is detected at an interval of M cells in the state of the phase, the synchronization state is set in the second phase, and the difference between the first phase and the second phase is discarded in the communication packet. The communication method according to claim 5, wherein the communication method is a number. 7. In a search state in which a frame head display is detected from an input communication packet, when a frame head display is detected, a transition is made to a synchronization detection state. In the synchronization detection state, M communication packets are transmitted. When the frame head display is not detected at an interval (hereinafter, referred to as a phase), the state transits to the search state. When the frame head display is detected at the phase, the state transits to the synchronization state at the phase. When the frame head display is detected in the phase, the frame remains in the synchronization state, and when the frame head display is not detected in the phase, the frame transitions to an out-of-synchronization state. If the head display is detected, the state transits to the synchronization state. If the number of protections is less than or equal to the number of protections, the protection processing of the frame head display is performed, and the frame remains in the out-of-synchronization state. If the frame start display is detected in the phase when the frame is in the phase, the state transits to the synchronous state in the phase and the number of communication packets corresponding to the difference between the phase in the synchronous state and the phase detected in the out-of-sync state 6. The communication method according to claim 5, wherein the frame head display is protected by outputting the number as a communication packet discard number. 8. A communication apparatus for performing transmission processing using a plurality of communication packets of a predetermined length P (P is a natural number) as a transmission processing unit M (M = P × J: J is an integer of 2 or more). The transmission data generation means for generating data and outputting a transmission end signal when the generation is completed, the transmission communication packet means for generating a transmission communication packet from the transmission data, and receiving the transmission end signal from the transmission data generation means At that time,
If the data amount Q (Q is a natural number) of the transmission communication packet generated by the transmission communication packet generation means is less than the transmission processing unit M, dummy data of at least the data amount (MQ) is generated and the transmission data is generated. Dummy transmission means for outputting to the generation means, the transmission communication packet generation means having a predetermined data amount M from the transmission data output from the transmission data generation means and the dummy data output from the dummy data generation means. A communication device for generating the transmission communication packet. 9. When the transmission data is image data,
9. The communication device according to claim 8, wherein the dummy data amount is at least two image units, and the data of each image unit is the same. 10. The communication device according to claim 9, wherein the image unit is a video frame or a video field. 11. A communication method for performing transmission processing of a plurality of communication packets of a predetermined length P (P is a natural number) in a transmission processing unit M (M = P × J: J is an integer of 2 or more). When the data amount of the data is less than the transmission processing unit (M), the communication packet is transmitted in the transmission processing unit (M) by adding at least dummy data of the data amount (MQ). 12. When the transmission data is image data, the dummy data amount is set to at least two image units, and the data of each image unit is the same.
The communication method described. 13. The communication method according to claim 9, wherein the image unit is a video frame or a video field.