JP2000115137A - Multimedia information communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform a sure and efficient mobile communication with communication equipment provided with a different error correction decoding function without complicating and enlarging the circuit of the communication equipment. SOLUTION: The communication equipment on a transmission side is provided with both of a convolution encoding processing circuit 141 and an RS encoding processing circuit 142, either one of the convolution encoding processing circuit 141 or the RS encoding processing circuit 142 is selected by changeover circuits 143 and 144 in accordance with the kind of an error correction decoding system imparted from the communication equipment on a reception side and an encoding rate or error correction ability is set to the selected encoding processing circuit in accordance with detail information transmitted from the communication equipment on the reception side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multimedia information communication system for multiplexing and transmitting a plurality of types of information data having an arbitrary amount of information in one packet.

[0002]

2. Description of the Related Art In order to realize wireless multimedia, it is necessary to multiplex voice, data and video for transmission.
In particular, in order to transmit and receive such information using a mobile terminal or the like, it is important that the information can be transmitted even in a poor environment such as a multipath fading environment.

Hitherto, as a multimedia multiplex transmission system used in a wireless environment, ITU-T Recommendation H.223 An
nex A / B / C are standardized. Figure 7 shows H.223 Annex A
The outline of / B / C is shown. As shown in FIG.
3 Annex A / B / C has a hierarchical structure, and the protection against errors becomes stronger as the Annex goes from A to C.

[0004] That is, Annex A (level 1) is H.223
Is replaced with a 16-bit PN sequence, and the multiplex header field and the adaptation layer (AL) are the same as in H.223.

[0005] Annex B (level 2)
The multiplex header of H.223 is changed in addition to the bit PN sequence. The level 2 header has a 4-bit multiplexed code (MC) field and an 8-bit multiplexed payload length (MPL) field (AL-PDU: AL header +
(Representing the length of the AL payload in octets). These 12 bits are (24,12,8) Go
protected by lay code.

Annex C (level 3) has the same multiplexing layer, synchronization flag, and header as level 2. This level 3 mainly adds a function of protecting the AL-PDU. AL-PDU consists of an optional header and AL-P
DU payload field. The optional header includes a 5-bit Sequence Number (SN) field and 2 additional bits. This 7-bit field is protected by a (16,76) BCH code. It is also possible to use a 10-bit SN, in which case it is protected by a (24, 12, 8) Golay code.

FIG. 8 shows the signal format of the level 3 adaptation layer. The AL-PDU payload includes a tail bit (TB) and a CRC for AL-SDU *.
Convolutional code (systematic convolutional code with a coding rate of 1/4)
And punctured in the range of 1/4 to 1. Optional ARQI,
It supports two types of ARQ, ARQII.

[0008] Further, as a further extended type of level 3,
H.223 Anne, an optional feature of H.223 Annex C above
xD has been proposed. This method protects data using a convolutional code in Annex C, but protects data using a Reed-Solomon (RS) code that is resistant to burst errors, and poor transmission path conditions such as mobile communication. This is the most effective method in an environment that is difficult.

FIGS. 10 to 12 show H.223 Annex C and H.22.
3 Shows the results of a computer simulation on the error correction capability of Annex D. 10 to 12, the burst error channel (average burst length 1 to 1000) based on the Gilbert model when the average bit error rate is 10 ⁻³ is shown.
Bit) and the length of AL-SDU * is 20,4.
The evaluation is performed when the number of bytes is fixed to 0, 60, 80, and 100 bytes. Also, in Annex C, since the convolutional code is a random error correction code, bit interleaving is added at the AL level to randomize burst errors. As can be seen from FIGS. 10 to 12, Annex D shows superior characteristics at the same coding rate such as r = 8/10 as compared with Annex C in the case of the same AL-SDU *.

FIG. 9 shows a signal format of the adaptation layer of Annex D. After adding a CRC to AL-SDU *, the GF
It is generated by encoding with the above RS code (2 ⁸ ).
In addition, ARQ by ARQI is optionally supported. The details of Annex D are described in ITU-T SG1
6Q. Contribution to Q11 Contribution Q11-G-09: Recommenda
tion H.223 / Annex D ', Whistler, Canada, 1998.

In general, a video coding system having an error resilience function by itself, such as MPEG4 or H.263 Version2, is annexed to a communication channel having an average bit error rate of about 10 ^-4 or less and having few errors. A multiplexing system such as A and B that does not have an error correction function in the payload in the multiplexing unit can also cope with it. However, if the state of the communication path becomes worse, the error correction function of the video coding method itself cannot be used. Without it, good quality video transmission cannot be achieved.

[0012]

As described above, in the mobile communication system, the state of the communication path is often worse than the bit error rate of 10 ^-4 except for some systems. The need to use is high. In consideration of application to a mobile communication system in which the state of the communication path is inferior, FIG.
12, the convolutional code of Annex C has a good correction capability when the coding rate is low, such as r = １ ／, but r = 8/1.
When the coding rate is high, such as 0, the transmission characteristics are significantly deteriorated, and the error correction effect is reduced. This has a direct effect on the transfer rate of transferable video data.

That is, when a strong error correction capability is expected, it is necessary to set a low coding rate such as r = 1/2. In this case, the rate of video data that can be transmitted is reduced to 1/2. This leads to degradation of image quality such as In order to improve image quality, a high coding rate such as r = 8/10 is set, so that almost no error correction effect can be expected.

As a solution to this problem, Annex
Some use D. However, when using Annex D,
Anne to ensure that it can communicate with all communication devices
xC is mandatory and Annex D is an option of Annex C. To configure a communication device that can use Annex D, in addition to the configuration corresponding to Annex C, it is necessary to have a function to encode and decode RS codes. And the circuit scale becomes enormous.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to provide a communication apparatus having different error correction decoding functions without increasing the complexity and size of the communication apparatus circuit. Another object of the present invention is to provide a multimedia information communication system capable of performing reliable and efficient mobile communication.

[0016]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention multiplexes a plurality of types of information data in one packet, and multiplexes the multiplexed signal from a transmitting communication apparatus to a receiving side. In a multimedia information communication system for transmitting to a communication device, a notifying means for sending, to a receiving communication device, a notification signal indicating a type of an error correction decoding function of the own device to a transmitting communication device prior to information communication. Is provided. On the other hand, the communication device on the transmission side has an error correction coding unit having a plurality of types of error correction coding functions including at least an error correction coding function corresponding to the error correction decoding function provided in the communication device on the reception side. Based on a notification signal sent from the communication device on the receiving side, a recognizing means for recognizing an error correction decoding function of the communication device on the receiving side, and based on a recognition result by the recognizing means, Selecting means for selecting and using an error correction coding function corresponding to the recognized error correction decoding function from the error correction coding functions.

Therefore, according to the present invention, the communication device on the transmission side is provided with all types of error correction coding functions that are assumed to be used, and responds to the notification of the error correction decoding function from the communication device on the reception side. A corresponding one of the above-described types of error correction coding functions is selected and used. Therefore, the communication device on the receiving side only needs to have one desired error correction decoding function, whereby the circuit configuration of the communication device can be simplified and miniaturized. In general, in error correction encoding / decoding processing, decoding processing requires a larger amount of signal processing and a larger circuit scale than encoding processing. Therefore, reducing the number of error correction decoding functions as described above has a great effect in reducing the circuit scale of the communication device.

Further, according to the present invention, when the communication device has a plurality of error correction decoding functions,
An error correction decoding function desired to be used is selected from among the plurality of error correction decoding functions, and only information relating to the selected function is transmitted to the communication device on the transmission side.

At this time, it is preferable to first transmit type information indicating the type of the error correction decoding function desired to be used, and then transmit detailed information necessary for setting the selected error correction decoding function.

With this configuration, the communication device on the receiving side only needs to notify only information relating to one error correction decoding function desired by itself, and the communication device on the receiving side is provided with the communication device on the receiving side. This eliminates the need to notify the transmitting-side communication device of information relating to all types of error correction decoding functions. For this reason, it is possible to reduce the information amount of the communication signal and shorten the time required for negotiation.

[0021]

FIG. 1 is a block diagram showing a configuration of a communication device used in a multimedia information communication system according to an embodiment of the present invention.

This communication device comprises a multiplexing unit, a demultiplexing unit 2, a radio unit (TX / RX) 3, and a main control unit 4.

The multiplexing unit 1 is for inserting video, audio and computer data into one packet, and includes a video encoder 11, an audio encoder 12,
It has a data input unit 13 and a multiplex processing circuit (MUX) 14.

The video encoder 11 converts a bit stream of video data into, for example, MPEG4 or H.263 vers.
The video AL-SDU is encoded by a video encoding method such as ion2 and is further divided into fixed lengths to generate a video AL-SDU. The speech encoder 12 is based on G.723.1, AAC, TW-
The input audio data is encoded using an audio encoding method such as VQ, and the encoded audio data is further divided into fixed lengths in the same manner as the video to generate an AL-SDU. The signal is input to the multiplex processing circuit 14. The data input unit 13 converts the input computer data and control data into AL-SD data according to H.245 + α.
U, and the AL-SDU of this data is input to the multiplex processing circuit 14.

The multiplexing processing circuit 14 converts the video, audio and data AL-SDUs input from the video encoder 11, the audio encoder 12 and the data input unit 13 into
The H.223 Annex C / D is selectively used for multiplexing, and the transmission multiplexed data MUX-PDU generated by the multiplexing process is output to the wireless unit 3.

The radio unit 3 modulates a radio carrier signal with the transmission multiplex data MUX-PDU,
This modulated wave signal is amplified to a predetermined transmission power and transmitted from the antenna to the wireless transmission path. In addition, after receiving a wireless carrier signal arriving from a communication device (not shown) of a communication partner via a wireless transmission path, demodulating the signal into baseband multiplexed data, the received multiplexed data is input to the demultiplexing unit 2.

The separation unit 2 separates and extracts video, audio, and computer data inserted in the received multiplexed data. The separation unit 2 (DEMUX) 21
, A video decoder 22, an audio decoder 23, and a data output unit 24.

The demultiplexing circuit 21 is provided with, for example, H.223 Annex C and D as a multiplexing system.
By selectively using C and D, the received multiplexed data MUX-
Video data, audio data and AL-SDU of computer data are separated and reproduced from the PDU.

The video decoder 22 and the audio decoder 23
The video and audio AL-SDUs output from the separation processing circuit 21 are decoded to reproduce the video and audio data bit streams. Data output unit 2
4 is A of the data output from the separation processing circuit 21.
Regenerate computer data or control data from L-SDU.

The main control unit 4 includes, for example, a microcomputer, and controls the operations of the multiplexing unit 1, the demultiplexing unit 2, and the radio unit 3 in an integrated manner.

The multiplexing circuit 14 is constructed as follows. FIG. 2 is a circuit block diagram showing the configuration. That is, the multiplexing processing circuit 14 includes the convolutional coding processing circuit 141 and the R as an error correction coding circuit.
An S encoding processing circuit 142 is provided, and these are selectively switched by switching circuits 143 and 144.

As shown in FIG. 3, the RS encoding processing circuit 142 includes an AL-SDU * cutout unit 142a, a CRC adding unit 142b, an RS encoding unit 142c, and an AL-SD
U * length measuring section 142d. AL-SDU
* The cut-out unit 142a outputs the AL-S of the input video.
The DU is divided into predetermined lengths, and AL-SDU * is output. The CRC adding unit 142b converts the above AL-SDU * into C
Add RC and tail bits. The AL-SDU * length measuring unit 142d measures the length of the AL-SDU * since the AL-SDU * is generally of a variable length, and outputs the measured value to the RS encoding unit 142d
c. The RS encoding unit 142c uses the AL-SD
Based on the AL-SDU * length given from the U length measuring unit 142d, the AL output from the CRC adding unit 142b
An RS code parity is generated and added to the information sequence consisting of -SDU * + CRC + tail bits.

The convolutional coding processing circuit 141 performs the above R
Similarly to the S encoding processing circuit 142, the input video AL-SDU is divided into predetermined lengths to obtain an AL-SDU *, and a CRC and tail bits are added to the AL-SDU, followed by convolutional encoding.

The convolutional coding processing circuits 141 and R
The video data error-correction-coded by the S-coding processing circuit 142 is input to the AL-PDU generator 146. The AL-PDU generator 146 adds a header to the error-correction-encoded video data, and inputs the AL-PDU of the video to which the header has been added to the MUX-PDU generator 147. MUX-PDU generator 147
Multiplexes the video AL-PDU together with the separately input audio AL-PDU and data AL-PDU into one multiplexed data MUX-PDU, and adds a MUX header to the multiplexed data MUX-PDU. After doing
Output to the wireless unit 3.

The main control unit 4 identifies the type of the error correction decoding circuit used by the receiving communication device based on information indicating the type of the error correcting decoding circuit notified from the receiving communication device described later. I do. Then, a selection instruction signal is given to the control circuit 145 in order to select an error correction coding circuit corresponding to the identified type of the error correction decoding circuit. Further, detailed information such as parameters received following the information indicating the type is provided to the control circuit 145.

The control circuit 145 switches between the selection circuits 143 and 144 in accordance with the selection instruction from the main control unit 4 and sends the selected convolutional coding processing circuit 141 and RS coding processing circuit 142 in accordance with the detailed information. Set the coding rate or error correction capability.

Next, an operation of selecting an error correction code / decoding method in the system configured as described above will be described.

First, the communication device on the receiving side sets the error correction method to 1
The case where only one is provided will be described.

Now, for example, it is assumed that only one convolution decoding circuit 212 is provided as an error correction decoding circuit in the separation unit 21 of the communication device on the receiving side as shown in FIG. The MUX-PDU separator 211 converts the received MUX-PDU into a video AL-PDU and an audio AL-PDU based on the contents of the MUX header.
And AL-PDU of data.

In this case, the main control unit 4 of the communication device on the receiving side
In the negotiation between transmission and reception performed prior to information communication, an error correction decoding circuit owned by the own apparatus is recognized, and information indicating the type of the recognized error correction decoding circuit, that is, the convolution decoding processing circuit 212 is transmitted to the transmitting side. To the communication device. Then, after transmitting this type information,
The detailed information such as parameters necessary for the convolutional encoding process is transmitted to the communication device on the transmission side.

On the other hand, the communication device on the transmitting side operates as follows. FIG. 4 is a flowchart showing the operation procedure and contents. That is, in the negotiation before information communication, the communication device on the transmission side first receives the type information sent from the communication device on the reception side in step 4a in the main control unit 4. Then, in step 4b, based on the received type information, an error correction decoding method possessed by the communication device on the receiving side is determined. As a result of this determination, since it is the convolutional decoding method, the process proceeds to step 4c, where the detailed information for the convolutional code / decoding process coming from the communication device on the receiving side is subsequently received. Then, in step 4d, the convolutional encoding processing circuit 141 is selected by controlling the switching of the switching circuits 143 and 144. At the same time, based on the detailed information sent from the communication device on the receiving side, the convolution decoding processing circuit 212 on the receiving side is sent to the convolutional coding processing circuit 141.
A coding rate or an error correction capability is set according to the capability possessed by.

If the error correction decoding circuit owned by the receiving communication device is an RS decoding processing circuit, the transmitting communication device shifts from step 4b to step 4e as shown in FIG. Receives detailed information for the RS encoding / decoding process coming from the communication device on the receiving side. Then, in step 4f, the RS encoding processing circuit 142 is selected by controlling the switching of the switching circuits 143 and 144. Also, the RS encoding processing circuit 14
For 2, the coding rate or the error correction capability according to the capability of the RS decoding processing circuit on the receiving side is set based on the detailed information sent from the communication device on the receiving side.

As described above, in the present embodiment, the transmission-side communication device is provided with both the convolutional coding processing circuit 141 and the RS coding processing circuit 142, and the error-correction decoding method notified from the receiving-side communication device. Switching circuits 143 and 144 in accordance with the type of
1 and the RS encoding processing circuit 142, and set the encoding rate or the error correction capability to the selected encoding processing circuit according to the detailed information transmitted from the communication device on the receiving side. Like that.

Therefore, the communication device on the receiving side is either the convolution decoding circuit 212 or the RS decoding circuit.
In spite of having only one, information communication can be reliably performed with the communication device on the transmission side. In addition, the convolution decoding processing circuit 212
Or any one of the RS decoding processing circuits,
The configuration of the separation unit 21 can be small and simple.

Next, a case where both the transmitting side and the receiving side support two error correction systems will be described.

For example, as shown in FIG. 5, a convolution decoding circuit 212 and an RS decoding circuit 2 are provided as error correction decoding circuits in the separation unit 21 'of the communication device on the receiving side.
13 are provided.

In this state, the main control unit 4 of the communication device on the receiving side
Recognizes an error correction decoding circuit owned by the own device in a negotiation between transmission and reception performed prior to information communication, and recognizes the recognized error correction decoding circuit, that is, the convolution decoding processing circuit 212 and the RS decoding processing circuit 213. Then, information specifying the type of the decoding processing circuit desired to be used is transmitted to the communication device on the transmitting side. Then, after transmitting the type designation information, detailed information such as parameters necessary for the encoding / decoding processing desired to be used is transmitted to the communication device on the transmission side.

Further, the communication device on the receiving side supplies a switching control signal from the control circuit 216 to the switching circuits 214 and 215 in order to select a decoding processing circuit desired to be used, whereby the coding processing desired to be used is performed. Connect the circuit.

On the other hand, the communication device on the transmitting side operates as follows. FIG. 6 is a flowchart showing the operation procedure and contents. That is, in the negotiation before information communication, the transmitting communication device first receives the coding system type designation information sent from the receiving communication device in step 6a in the main control unit 4. And
In step 6b, based on the received type designation information, an error correction decoding system desired by the receiving communication apparatus to be used is determined. If the result of this determination is that the convolutional decoding method is now desired, the process proceeds to step 6c, where detailed information for convolutional encoding / decoding processing coming from the communication device on the receiving side is subsequently received. And step 6
At d, the convolutional coding processing circuit 141 is selected by controlling the switching of the switching circuits 143 and 144. At the same time, based on the detailed information sent from the communication device on the receiving side, the convolutional coding processing circuit 141 is provided with a coding rate or error correction capability according to the capability of the convolutional decoding processing circuit 212 on the receiving side. Set.

On the other hand, if the error correction decoding circuit that the receiving communication device desires to use is the RS decoding processing circuit 213, the transmitting communication device performs step 6 as shown in FIG.
The process proceeds from step b to step 6e, where the detailed information for the RS encoding / decoding process coming from the communication device on the receiving side is received. Then, in step 6f, the switching circuit 14
By controlling the switching of the RS encoding processing circuits 3 and 144, the RS encoding processing circuit 142 is selected. At the same time, based on the detailed information sent from the communication device on the receiving side, the RS encoding processing circuit 142 is given a coding rate or error correction capability according to the capability of the RS decoding processing circuit on the receiving side. Set.

As described above, in the present embodiment, when the separation unit 21 'of the communication device on the receiving side has a plurality of error correction decoding circuits, the communication device on the receiving side first requests the error correction coding / decoding circuit to use. Sends type designation information for designating the type of decoding system, and then sends detailed information on the error correction coding / decoding system desired to be used, and the communication device on the transmitting side responds based on the type designation information. The error correction coding processing circuit to be executed is selected, and the coding rate and the like are set in the error correction coding processing circuit based on the detailed information.

Therefore, even when a plurality of error correction decoding systems are provided, information to be transmitted to the communication device on the transmission side only needs to be information on the error correction decoding system desired to be used. For this reason, the amount of information to be notified from the receiving side to the transmitting side is significantly reduced as compared with a conventional system that transmits all the detailed information relating to a plurality of error correction coding / decoding schemes, thereby reducing the time required for negotiation. Can be greatly reduced.

The present invention is not limited to the above embodiment. For example, in the above-described embodiment, a case has been described as an example in which the communication device on the transmission side has two systems of the convolutional coding system and the RS coding system as the error correction coding system. You may have it.

In addition, the configuration of the communication device, the procedure for selecting the coding method, and the contents thereof can be variously modified without departing from the gist of the present invention.

[0055]

As described above in detail, according to the present invention, a plurality of types of error correction codes including at least a function of error correction coding corresponding to an error correction decoding function provided in a communication device of a receiving side are provided in a communication apparatus of a transmitting side. Signal, which is provided with an error correction coding unit with a decoding function, and notifies the communication device on the receiving side of a notification signal indicating the type of the error correction decoding function provided on the communication device on the receiving side prior to information communication. However, the communication device on the transmitting side recognizes the error correction decoding function provided in the communication device on the receiving side based on the notification signal sent from the communication device on the receiving side. An error correction coding function corresponding to the recognized error correction decoding function is selected from the error correction coding functions and is made usable.

Therefore, according to the present invention, multimedia information communication capable of performing reliable and efficient mobile communication with a communication device having different error correction decoding functions without causing the circuit of the communication device to become complicated and large. A system can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a communication device used in a multimedia information communication system according to an embodiment of the present invention.

FIG. 2 is a circuit block diagram showing a first example of a configuration of a multiplexing unit and a demultiplexing unit of the communication device shown in FIG.

FIG. 3 is a diagram showing an example of an R provided in the multiplexing unit shown in FIG. 2;
FIG. 3 is a circuit block diagram illustrating a configuration of an S encoding processing circuit.

FIG. 4 is a flowchart showing a procedure of selecting and controlling an error correction coding scheme in the multiplexing unit shown in FIG. 2;

FIG. 5 is a circuit block diagram showing a second example of the configuration of the multiplexing unit and the demultiplexing unit of the communication device shown in FIG.

FIG. 6 is a flowchart showing a control procedure for selecting an error correction coding scheme in the multiplexing unit shown in FIG. 5 and its contents.

FIG. 7 is a diagram showing an outline of a hierarchical structure of H.223 Annex A / B / C.

FIG. 8 is a diagram showing a signal format of an adaptation layer of Annex C.

FIG. 9 is a diagram showing a signal format of an adaptation layer of Annex D.

FIG. 10: Annex C and Ann when the coding rate r = 8/10
The figure which shows the comparison of the error characteristic with exD.

[Fig. 11] Annex C and Ann when coding rate r = 8/12
The figure which shows the comparison of the error characteristic with exD.

FIG. 12: Annex C and Annex when coding rate r = １ ／
9 is a diagram showing a comparison of error characteristics with D. FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Multiplexing unit 2 ... Demultiplexing unit 3 ... Wireless unit 4 ... Main control part 11 ... Video encoder 12 ... Audio encoder 13 ... Data input part 14 ... Multiplexing processing circuit 21 ... Demultiplexing processing circuit 22 ... Video decoding Device 23 ... Speech decoder 24 ... Data output unit 141 ... Convolution coding processing circuit 142 ... RS coding processing circuit 142a ... AL-SDU * cutout unit 142b ... CRC adding unit 142c ... RS coding unit 142d ... AL-SDU * Length measuring units 143, 144 Switching circuit 145 Control circuit for multiplex processing circuit 146 AL-PDU generator 147 MUX-PDU generator 211 MUX-PDU separator 212 Convolution decoding processing circuit 213 RS decoding processing Circuits 214, 215: Switching circuit 216: Control circuit of separation processing circuit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // H04N 7/08 H04N 7/08 Z 7/081 F term (Reference) 5C059 KK06 MA00 RA04 RA08 RB02 RE16 RF05 SS06 TA76 TC45 5C063 AB03 AB07 AC01 AC05 CA23 CA34 CA36 EB31 5J065 AC02 AD10 AE06 AF03 AF04 AH07 AH09 AH22 5K014 AA01 AA02 BA10 DA01 FA11 HA01 HA10 5K035 AA03 BB01 DD01 HH07 JJ01 MM09

Claims (3)

[Claims] 1. A multimedia information communication system for multiplexing a plurality of types of information data into one packet and transmitting the multiplexed signal from a communication device on a transmission side to a communication device on a reception side. The communication device includes a notification unit that sends a notification signal indicating a type of an error correction decoding function included in the communication device to the communication device on the transmission side, prior to communication of the information. The communication device on the transmission side includes the communication on the reception side. An error correction encoding unit having a plurality of types of error correction encoding functions including at least an error correction encoding function corresponding to the error correction decoding function provided in the device, and a notification signal sent from the communication device on the receiving side. And
A recognition unit that recognizes an error correction decoding function included in the communication device on the receiving side; and, based on a recognition result obtained by the recognition unit, corresponds to the recognized error correction decoding function from the plurality of types of error correction coding functions. A multimedia information communication system comprising: a selection unit for selecting and using an error correction coding function. 2. When the communication device on the receiving side has a plurality of error correction decoding functions, the notifying means selects an error correction decoding function desired to be used from among these error correction decoding functions. 2. The multimedia information communication system according to claim 1, wherein only information relating to the selected function is transmitted to the communication device on the transmission side by a notification signal. 3. The notifying means first sends type information indicating a type of an error correction decoding function desired to be used, selected from a plurality of types of error correction decoding functions, and then transmits the selected error correction decoding function. 3. The multimedia information communication system according to claim 2, wherein detailed information necessary for setting a function is transmitted.