JPH07283757A - Sound data communication equipment - Google Patents

Abstract

PURPOSE:To reduce the probability of abort of the received data due to the data errors even if the noises are increased in a reception environment. CONSTITUTION:A sound data receiving device 1A receives the sound data from a sound data transmitting device 10. Then the device 1A detects the errors of received data by a CRC bit decider unit 1E and produces a message to designate the data compression rate and the retransmission frequency of the transmitter side by a message generator 1G based on the error rate decided by an error rate decider unit 1F to send the message to the device 10. Thus a coder 13 of the device 10 compresses the sound data at a designated rate. A CRC bit generator 14 adds a CRC bit to the compressed data to generate the compressed data packets and stores these packets in a data buffer 15. Meanwhile a retransmission counter 16 counts the retransmission frequency designated by the message and reads the compressed data packets out of the buffer 15 in the counted frequency to array them in a single frame and then sends out these packets by a transmitter 19.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voice data communication device in the field of wireless communication.

[0002]

2. Description of the Related Art In recent years, in voice transmission by radio communication, a transition from an analog system to a digital system is progressing.

A conventional voice data communication device will be described below with reference to the drawings. FIG. 3 is a block diagram showing a schematic configuration of a voice data transmitting device and a voice data receiving device in a conventional voice data communication device. In the figure,
Reference numeral 30 is a voice data transmitter, and 36 is a voice data receiver. In the voice data transmitting device 30, 31 is a microphone (hereinafter, referred to as a microphone) for capturing voice, 32
Is a PCM modulator / demodulator (hereinafter referred to as PCM CODEC) that digitally encodes the captured voice, 33 is an encoder that compresses the digitally encoded voice data at a variable rate, and 34 is a CRC bit for the compressed data. A CRC bit generator, 35 is a transmitter for transmitting data by placing it on radio waves. Further, in the audio data receiving device 36, 3B is a receiver for receiving the data, and 3A is a CRC bit added to the received data to check whether the received data includes an error (hereinafter referred to as an error). CRC bit determiner for determining whether or not, 39 is a compound device for decompressing compressed data, and 38 is a PCM CODE for decoding digitally encoded data into analog voice data.
C and 37 are speakers that output audio.

The operation of the above configuration will be described with reference to the drawings. FIG. 4 is a schematic diagram showing a time-series structure of data to be transmitted and received. When transmitting the voice data, the voice data transmitting device 30 first encodes the voice input from the microphone 31 into digital data by the PCM CODEC 32, and the encoder 33 performs the digital encoding as shown in FIG. The data 41 is divided into frames 42 that are data of a fixed time length, and each frame 42 is compressed. Here, the encoder 33 generates compressed data 43 by compressing at a compression rate according to the amount of information when there is sound and when there is no sound. CR
The C bit generator 34 adds CRC bit 4 to the compressed data 43.
4 is added and output to the transmitter 35. In the following description, data obtained by adding CRC bits to compressed data is called a compressed data packet. The transmitter 35 transmits the compressed data packet 45 on radio waves.

The voice data receiver 36 receives the compressed data packet 45 at the receiver 3B, and the CRC bit determiner 3
A determines a data error in the received compressed data packet 45 and, if an error is included, discards the received compressed data packet. The compounder 39 inputs only the compressed data packet 45 containing no error, decompresses it, and outputs it to the PC.
Output to M CODEC38, PCM CODEC38
Demodulates the input digital voice signal into an analog voice signal, and the speaker 37 converts the voice signal into voice and outputs the voice. Therefore, the compressed data including the error is not output from the speaker 37.

[0006]

In such a conventional voice data communication apparatus, when the noise power of the reception environment increases when there is a sound, the error rate of the reception data increases,
There is a problem that the probability that the compressed data packet is discarded increases, and the output voice tends to be interrupted.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a voice data communication device which reduces an error rate and prevents voice from being interrupted.

[0008]

In order to achieve the above object, the present invention provides a voice data transmitting apparatus and a voice data receiving apparatus for wireless communication for compressing and transmitting voice data at a variable rate. The apparatus uses a predetermined first audio data obtained by digitally encoding an analog audio signal.
Data having a second time length shorter than the first time length and having a compression ratio specified by a message sent from the voice data receiving device. Encoding means for compressing into
An error detection bit generating means for adding an error detection bit to the compressed data to generate a compressed data packet, a data buffer means for storing the compressed data packet, and a data buffer means for counting the number of times designated by the message. The audio data receiving device is transmitted from the audio data transmitting device, and the resending counter device reads out the compressed data in the number of times, arranges it in the first time length section, and outputs it to the transmitting device. Receiving means for receiving data, error detection determining means for extracting only error-free data from a plurality of compressed data packets in the received frame, and error rate for determining error detection error rate in the error detection determining means The judgment means and the audio data transmitter are controlled by the error rate corresponding to the error rate. A composite for transmitting a digital coded voice data by decompressing one of the error-free compressed data packets output by the error detection / judgment means, and a retransmission instruction message generation means for generating a message instructing the rate and the number of retransmissions. The audio data receiving apparatus sends to the audio data transmitting apparatus a message requesting that the compression rate and the number of retransmissions be increased as the error rate of the received data increases. Is a voice data communication device adapted to transmit a compressed data packet at the compression rate and the number of retransmissions designated by the message.

[0009]

According to the present invention, in the above configuration, the voice data receiving device generates a message requesting that the compression rate and the number of retransmissions on the transmitting side be increased in accordance with the reception error rate, and then the voice data transmitting device generates. The audio data transmitting device transmits the audio data at the compression rate and the number of retransmissions designated by the message.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a voice data communication device of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of this embodiment. In the figure, 10 is a voice data transmitter, and 1A is a voice data receiver. In the voice data transmitting apparatus 10, 11 is a microphone for capturing voice, 12 is a PCM CODEC for digitally encoding the captured voice, 13 is an encoder for compressing the digitally encoded voice data at a variable rate, 14
Is a CRC bit generator for adding CRC bits to compressed data, 15 is a data buffer for storing data with CRC bits added, 16 is a retransmission counter for counting the number of times data is retransmitted and shown in the data buffer 15, and 17 is a voice A retransmission instruction message decoder for decoding the retransmission instruction message from the data receiving apparatus 1A, 18 is a receiver for receiving the data transmitted from the voice data receiving apparatus 1A, 19
Is a transmitter for transmitting data on radio waves.

Further, in the voice data receiving device 1A,
1H is a receiver for receiving the data transmitted from the audio data transmitter, 1E is C added to the received data
CRC bit determiner 1F for checking CRC bit to determine error in received data 1F is CRC bit determiner 1E
Error rate determiner that monitors the error detection rate of 1G
Is a retransmission instruction message generator for generating a retransmission instruction message, 1J is a transmitter for transmitting data on radio waves, 1J
D is a compound device for decompressing compressed data, 1C is a PCM for decoding digitally encoded data into analog data
CODECs 1B are speakers that output audio.

The mutual relationship and operation of the above components will be described below with reference to the drawings. Note that FIG. 4 is a schematic diagram showing a data structure in time series in the present embodiment. In the present embodiment, the voice data transmitting device 10 captures voice with the microphone 11, and uses the PCM CODEC 1
2, the voice is digitally encoded, the digital data 21 encoded by the encoder 13 is divided into data of a fixed time length, which is compressed and converted into compressed data 23,
The operation until the CRC bit generator 14 adds the CRC bit 24 to generate the compressed data packet 25 is basically the same as the conventional example.

The difference of this embodiment from the conventional example is that when the noise power in the reception environment increases when there is a sound, the error of the received data from the audio data receiving apparatus 1A increases, so that the compressed data packet is retransmitted. A point that the message requesting the data transmitting apparatus 10 is transmitted, the voice data transmitting apparatus 10 receiving the message sets a high compression rate, and transmits a compressed data packet with a reduced time length to the voice data receiving apparatus 1A multiple times. It is in. In this case, the retransmission instruction message generator 1G of the voice data receiving device 1A generates a message requesting the compression rate according to the error rate determined by the error rate determiner 1F and the number of retransmissions according to the error rate, The transmitter 1J transmits the voice data transmitting device 10. This message is a message notifying that the compression rate is set to be higher when the error rate is high than when the error rate is low, and also notifies that the number of retransmissions should be increased. In the audio data transmitter 10, as shown in FIG. 4, the time length of the compressed data packet 25 is shortened by increasing the compression rate, and it is possible to transmit the compressed data packet 25 a plurality of times.

The voice data transmitter 10 receives the message by the receiver 18, decodes the message by the retransmission instruction message decoder 17, sets the retransmission counter 16 according to the number of retransmissions instructed by the message, and the encoder. The compression rate of 13 is controlled. Encoder 1
3 compresses the voice digital data 21 at the instructed compression rate, and the CRC bit generator 14 converts the compressed data 23 into C
The RC bit 24 is added to form a compressed data packet 25, which is stored in the data buffer 15. Retransmission counter 1
Reference numeral 6 counts the number of times specified by the message, and the compressed data packet 25 is repeatedly read from the data buffer 15 so as to be incorporated in the time interval of one frame by the number of times and input to the transmitter 19, and the transmitter 19
Transmits the data for one frame wirelessly.

In the audio data receiving apparatus 1A, one frame of audio data is received by the receiver 1H, and the CRC bit judging device 1E checks the CRC bit 24 of the compressed data packet 25 to perform compression without error in one frame. One data packet is taken out, the compressed data is expanded by the decompressor 1D, decoded into an analog audio signal by the PCM CODEC 12, and the audio is output from the speaker 1B. FIG. 4 shows one frame 22 of compressed data packet 25.
The case where the data is repeatedly sent three times within the time period of is shown.

By the above operation, when there is a voice and the reception error rate is high, the higher the error rate is, the higher the compression rate is set and the more the number of times of retransmission is transmitted, so that the sound quality of the received voice is deteriorated. The discard rate of the received data is reduced according to the number of times the data packet is retransmitted, the output voice is less interrupted, and highly reliable voice data transmission becomes possible.

In this embodiment, the error detection and correction method uses C
Although RC coding was used, it goes without saying that other forms of coding may be used.

[0018]

As is apparent from the above description, the present invention provides a voice data transmitting apparatus and a voice data receiving apparatus for wireless communication for compressing and transmitting voice data at a variable rate, the voice data transmitting apparatus comprising: Audio data obtained by digitally encoding an analog audio signal is divided into frames of a predetermined first fixed time length, and the data of the frame is data of a second time length shorter than the first time length and Encoding means for compressing data having a compression ratio designated by a message sent from a data receiving device, error detection bit generating means for adding an error detection bit to the compressed data to generate a compressed data packet, and the compressed data packet And a compression buffer in the data buffer means for counting the number of times specified by the message. The audio data receiving device receives the data transmitted from the audio data transmitting device, the retransmission data receiving device receives the data transmitted from the audio data transmitting device. Receiving means, an error detection determining means for extracting only error-free data from a plurality of compressed data packets in the received frame, and an error rate determining means for determining an error rate of error detection in the error detection determining means. Retransmission instruction message generating means for generating a message instructing the compression rate and the number of retransmissions to the voice data transmitting device corresponding to the error rate, and one of the error-free compressed data packets output by the error detection determining means. And a composite means for outputting digitally encoded audio data. The receiving device sends a message to the voice data transmitting device requesting that the compression rate and the number of retransmissions be increased as the error rate of the received data increases, and the voice data transmitting device specifies the compression rate specified by the message. By sending compressed data packets with the number of times of retransmission and the number of retransmissions, even if the reception error rate increases due to an increase in noise in the receiving environment, the rate of discarding voice data due to errors is reduced and highly reliable voice data Transmission becomes possible.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of a voice data communication device of the present invention.

FIG. 2 is a schematic diagram showing a configuration of voice data and a compressed data packet in the voice data communication device of the present invention.

FIG. 3 is a block diagram showing a configuration of a conventional voice data communication device.

FIG. 4 is a schematic diagram showing a configuration of voice data and a compressed data packet in a conventional voice data communication device.

[Explanation of symbols]

1A Audio data receiving device 1D Combiner (combining means) 1E CRC bit judging device (error detecting judging means) 1F Error rate judging device (error rate judging means) 1G Retransmission instruction message generator (retransmission instruction message generating means) 1H Receiver (Reception means) 10 Voice data transmission device 13 Encoder (encoding means) 14 CRC bit generation means (error detection bit generation means) 15 Data buffer (data buffer means) 16 Retransmission counter (retransmission counter means) 17 Transmitter (transmission means) )

Claims (1)

[Claims] 1. A voice data transmitting apparatus and a voice data receiving apparatus for wireless communication, wherein voice data is compressed at a variable rate and transmitted / received, wherein said voice data transmitting apparatus has a predetermined voice data obtained by digitally encoding an analog voice signal. First
Data having a second time length shorter than the first time length and having a compression ratio specified by a message sent from the voice data receiving device. Encoding means for compressing into
An error detection bit generating means for adding an error detection bit to the compressed data to generate a compressed data packet, a data buffer means for storing the compressed data packet, and a data buffer means for counting the number of times designated by the message. The audio data receiving device is transmitted from the audio data transmitting device, and the resending counter device reads out the compressed data in the number of times, arranges it in the first time length section, and outputs it to the transmitting device. Receiving means for receiving data, error detection determining means for extracting only error-free data from a plurality of compressed data packets in the received frame, and error rate for determining error detection error rate in the error detection determining means The judgment means and the audio data transmitter are controlled by the error rate corresponding to the error rate. A composite for transmitting a digital coded voice data by decompressing one of the error-free compressed data packets output by the error detection / judgment means, and a retransmission instruction message generation means for generating a message instructing the rate and the number of retransmissions. The audio data receiving apparatus sends to the audio data transmitting apparatus a message requesting that the compression rate and the number of retransmissions be increased as the error rate of the received data increases. Is a voice data communication device adapted to transmit a compressed data packet at a compression rate and the number of retransmissions designated by the message.