JPH09139980A - Receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely prevent a noise output by applying demodulation processing to voice data when a discrimination means discriminates a 1st state and interpolating data for a prescribed period with other voice data when the discrimination means discriminates a 2nd state. SOLUTION: After a de-interleave circuit 51 in a data processing section 5 conducts de-interleave processing to replace sequence of received data, the result is fed to a convolution decoding circuit 52, in which decoding processing is conducted. In this case, the circuit 52 discriminates a content of the decoded data depending on a state of specific bit data added to each slot. As the interpolation processing, the data for one slot period having an error or one preceding slot to a command of transmission of a high speed additional channel FACCH are to be interpolated. A voice data memory 62 storing voice data up to one preceding slot period is connected to a voice decoding circuit 61 and the interpolation processing is conducted by using the voice data of one preceding slot period stored in the memory 62.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiver suitable for application to, for example, a digital radiotelephone device for transmitting and receiving voice data converted into digital data.

[0002]

2. Description of the Related Art Audio data converted into digital data
Wireless communication is performed between a base station, which is placed in a predetermined state within the service area, and a terminal device (mobile station), so that a voice call can be made between a partner connected to the base station and a specific terminal device. Various digital wireless telephone systems that have been made possible have been put into practical use. In this case, the terminal device is configured to demodulate the received audio data into an analog audio signal and supply the analog audio signal to the speaker. In the case of the system that transmits the voice data converted into digital data, the quality of the call voice can be improved as compared with a so-called analog wireless telephone system that transmits an analog voice signal.

By the way, in the radio telephone system, various control data and the like can be transmitted at the same time in addition to voice data. For example, various commands can be sent from the base station to the terminal device.

On the other hand, the voice data transmitted by the digital radio telephone system is designed to be transmitted with error detection coding, so that the reception side terminal has an error in the received voice data due to the error detection code. When detected, the audio data before and after the section in which the error is detected is interpolated, and the interpolated audio is output from the speaker.

[0005]

By the way, depending on the format of the data to be transmitted, some control data may be temporarily transmitted in the section in which the voice data is transmitted. That is, in the case of the digital cellular system,
If the low-speed accompanying channel used for transmitting data with a relatively small amount of information is set separately from the voice data transmission section, and the control data with a relatively small amount of information is transmitted, this low-speed accompanying channel is used. Is used. On the other hand, when transmitting data having a relatively large amount of information from the base station, for example, the transmission of voice data in one slot section is stopped, and the section in which this voice data is transmitted is controlled as a high-speed associated channel. Data may be transmitted.

In this case, if the terminal side receiving this control data is performing error detection using the error detection code, it is detected that there is an error because the data has a different format from the voice data, and the control data is detected. The data of the inserted section is interpolated with the immediately preceding audio data,
The control data is processed so as not to be output as voice (noise).

However, although the probability of occurrence is low, when control data is transmitted instead of voice data, there is a possibility that it will be detected as no error by the detection processing using the error detection code. When it is detected that there is no error, the audio data processing circuit treats the control data as audio data and processes it, and noise (abnormal noise) resulting from analog conversion of the control data is output from the speaker.

In view of the above point, the present invention has an object to prevent noise due to transmission of data other than voice data such as control data from being output as voice.

[0009]

In order to solve this problem, the present invention comprises a discriminating means for discriminating predetermined bit data included in received data and a voice data processing means for demodulating voice data. When the discriminating means discriminates the first state, the voice data processing means demodulates the voice data included in the received data, and when the discriminating means discriminates the second state, the voice data processing means converts the received data into the received data. The data of the included predetermined section is interpolated by other audio data.

With this configuration, when data other than the voice data is transmitted in the voice data section, the voice data is interpolated without using this data, and the data other than the voice data such as the control data is transmitted. In this case, this data will not be output as voice data.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will now be described with reference to FIGS.
This will be described with reference to FIG.

The present embodiment is applied to a terminal device of a digital cellular radio telephone system in which digitalized voice data is transmitted. As a communication system between the base station and the terminal device, A TDMA method (time division multi) in which burst data having a slot configuration is transmitted and received intermittently at periodic timings.
(iplex access method: time division multiple access method)
The system to which is applied.

FIG. 1 shows the overall configuration of a mobile phone 1 which is a terminal device of this example. First, the receiving system will be explained.
The signal received by the antenna 2 is supplied to the high frequency unit 3. The high frequency unit 3 frequency-converts a reception signal of a predetermined frequency (channel) into an intermediate frequency signal, and supplies the obtained intermediate frequency signal to the demodulation circuit 4. The demodulation circuit 4 performs a demodulation process corresponding to the modulation method applied to this wireless telephone system. Then, the demodulated signal is supplied to the data processing unit 5.

In the data processing unit 5, the slot timing of the demodulated received signal is determined from the sync word included in the received signal, and the data in each determined slot is interleaved on the transmitting side. De-interleave processing is performed in reverse (that is, the original data array is restored). Then, convolutional decoding processing such as Viterbi decoding is performed on data in a predetermined section such as voice data in the de-interleaved data.

Then, the audio data in the decoded received data is supplied to the audio processing unit 6, and the audio processing unit 6 decodes it into digital audio data of a predetermined format. For example, ADPCM (Adaptive Different)
Tial Pulse Code Modulatio
The audio data bit-compressed by the n) method is decoded into audio data of a predetermined sampling frequency, and error detection processing is performed based on the error detection code CRC added to the audio data at the time of this decoding to detect an error. If so, the immediately preceding audio data is used to perform interpolation processing. Then, the decoded voice data is converted into an analog voice signal, and the converted analog voice signal is subjected to analog processing such as amplification. Then, the analog-processed audio signal is supplied to the speaker 7 as the output of the audio processing unit 6, and the audio is output.

Further, the control data included in the received data decoded by the data processing unit 5 is transferred to the portable telephone 1
To the control unit 10, which is a system controller that controls the operation of each unit. The control unit 10 is composed of a microcomputer, and sets the transmission state and the reception state based on the supplied control data, for example.

Next, the structure of the transmission system will be described.
The sound picked up by the microphone 8 is supplied to the sound processing unit 6 as a sound signal, converted into digital sound data of a predetermined sampling frequency by the sound processing unit 6, and then converted into bit-compressed sound data of a predetermined system. To do. For example, it is converted into audio data compressed by the ADPCM method.

Then, the converted voice data is supplied to the data processing unit 5, and a channel coding process is performed for arranging it at predetermined positions within one slot for each predetermined section. In this case, the error correction code CRC is added to the supplied voice data, and the control data such as the low-speed associated channel and the steal bit flag supplied from the control unit 10 are arranged at a predetermined position in each slot. . further,
Fixed patterns such as preambles and sync words are also placed at fixed positions. Then, the transmission data having the slot configuration is modulated by a predetermined modulation method, and the interleaving process for changing the data array is performed.

Then, the transmission data of the slot structure thus processed for transmission is supplied to the modulation circuit 9 and subjected to modulation processing by the modulation method applied to this radio telephone system. Is supplied to the high frequency unit 3 for frequency conversion into a predetermined transmission frequency (transmission channel), amplification processing for transmission is performed, and the processed transmission signal is wirelessly transmitted from the antenna 2.

The mobile phone 1 of this embodiment is provided with keys 11 such as dial keys, and operation information of the keys 11 is supplied to the control unit 10. Further, a display unit 12 including a liquid crystal display panel is connected to the control unit 10, and the control unit 10
Based on the control, various messages such as telephone number and communication status can be displayed with letters, numbers and symbols.

Next, in the reception processing in the data processing unit 5 and the voice processing unit 6 of the mobile phone 1 of this example, the details of the processing until the voice data is extracted from the received data to obtain the analog voice signal will be described. This will be described with reference to FIG.

First, the de-interleave circuit 51 in the data processing unit 5 performs de-interleave processing for changing the order of received data, and then the convolutional decoding circuit 52.
To perform decoding processing. In this case, the decoding circuit 52 determines the content of the decoded data based on the state of the specific bit data added to each slot.

Here, the slot configuration of the mobile phone 1 of this example for wireless transmission with the base station will be described. As the slot configuration, a control slot used for transmitting control data and a communication slot used for transmitting voice data and the like are defined. Here, the communication slot for transmitting voice data and the like will be described. FIG. 3 is a diagram showing a structure of one slot of this communication slot. One slot is composed of a predetermined number of bits, and a preamble, voice data TCH, a sync word, and a color code (for recognition with a mobile station) in order from the beginning. Code data), steal bit flag SF, low speed associated channel SACCH, audio data TC
H, and the number of bits in each section is determined. In this case, the error detection code CRC is added to the section of the voice data TCH. Further, in the case of this example, the communication configuration is such that one slot is transmitted at an interval of 20 msec.
In the voice data TCH in the slot section, voice data for a total of 20 msec is compressed and arranged.

When it is necessary to transmit control data having a relatively large number of bits, the voice data TCH
High-speed accompanying channel FAC as control data in the section
Place CH. This high-speed accompanying channel FACCH
Is placed instead of the voice data TCH, 1
The steal bit flag SF of a bit is set to a predetermined state (for example, “1” data), and when the data is other data (that is, when the audio data TCH is transmitted), the steal bit flag SF is set to another state (for example, “0” data). ).

The data having such a slot structure is decoded by the decoding circuit 52. In the case of this example, the data of the steal bit flag SF is supplied to the audio processing unit 6. That is, the audio data TCH obtained by the decoding circuit 52 is
It is supplied to the voice decoding circuit 61 in the voice processing unit 6 and a 1-bit steal bit flag SF is provided in one slot.
Data is supplied to the audio decoding circuit 61. In addition, the low-speed associated channel SA decoded by the decoding circuit 52
The data of CH and the data of the high-speed associated channel FACCH are supplied from the control data output terminal 53 to the control unit 10 side.

Then, the voice decoding circuit 61 in the voice processing unit 6 decodes the bit-compressed voice data into voice data having a predetermined sampling frequency, and also performs error detection processing based on the error detection code CRC. If an error is detected, the immediately preceding audio data is used to perform interpolation processing. Further, even when the transmission of the high-speed associated channel FACCH is instructed by the supplied data of the steal bit flag SF, the interpolation processing is performed using the immediately preceding audio data as in the case of error detection.

As the interpolation processing, one slot period in which this error is detected, or the high speed associated channel FAC is used.
A process of interpolating the 1-slot period for which CH transmission is instructed with the voice data of 1-slot before is performed. In this case, the voice decoding circuit 61 is connected to a voice data memory 62 that stores voice data up to at least one slot period before, and the voice data stored in the memory 62 before the one slot period is used for interpolation. Perform processing to

Further, when the interpolation processing is performed using the voice data of the one slot period before, the voice output is performed by a predetermined level (for example, about 4 dB) as compared with the level of the voice data of the immediately preceding slot period. Perform processing to lower the level. Such an interpolation process is a process referred to as bad frame masking.

Then, the audio data thus interpolated as necessary is supplied to the digital / analog converter 63 in the audio processing unit 6 to be converted into an analog audio signal and converted into an analog audio signal. Perform output processing such as amplification.

Here, the judgment in the case of executing the interpolation processing in the voice decoding circuit 61 of this example is shown in FIG. 4, where the voice data of the one-slot section (or the data of the high-speed associated channel) is shown in the voice decoding circuit 61. Is supplied (step 10
1), judging the data of the steal bit flag SF,
It is determined whether or not the flag is a flag when the high speed associated channel FCCH is received (step 102). If it is determined from the flag SF that the channel is not the high-speed associated channel FCCH (that is, voice data), error detection processing is performed based on the error detection code CRC added to the voice data TCH, and an error is detected. It is determined whether or not (step 103). If no error is detected here, normal decoding processing is performed (step 10).
Along with 4), the voice data stored in the voice data memory 62 is updated to the voice data of the 1-slot section at this time (step 105). Then, when the audio data of the next 1-slot section is supplied, the process returns from step 101.

When it is determined in step 102 that the flag is a flag when the high speed associated channel FCCH is received, or when it is determined in step 103 that there is an error in the voice data, the process proceeds to step 111, and one slot before is sent. The voice data is read from the memory 62, and interpolation processing is performed to replace the read voice data. When the interpolation processing is performed in step 111, the level of the replaced audio data is set to a predetermined level (here, about 4 dB).
The lowering process is performed (step 112). And next 1
When the voice data of the slot section is supplied, step 10
Return to processing from 1.

Thus, according to the wireless telephone 1 of this example,
When high-speed accompanying channel data (control data) is transmitted from the base station side instead of voice data, the data of the steal bit flag SF is determined and interpolation processing is performed unconditionally. In comparison with the case where the interpolation process is performed only when an error is detected by the error detection process using the error detection code added to the audio data, the interpolation process is executed reliably.

In other words, in the error detection process using the error detection code, there is a possibility that the control data may be accidentally detected as no error due to the data structure of the high-speed accompanying channel and the control data may be output as voice. On the other hand, in the case of this example, when the data of the high-speed associated channel is transmitted, the interpolation process is executed based on the steal bit flag SF, the data of the high-speed associated channel is output as voice, and noise is generated. It is possible to prevent the accident that is temporarily output. Therefore, even when the high-speed associated channel is temporarily received, the sound that has been subjected to good sound processing can be reliably output, and the accident that temporarily outputs noise (abnormal sound) can be prevented.

Although it is unlikely that the steal bit flag SF is erroneously detected, even if it is erroneously detected, there is a high possibility that the error detection processing by the error detection code will detect that there is an error and that the interpolation processing will be performed. Therefore, from this point as well, the circuit of this example is unlikely to malfunction.

Although the above embodiment is applied to the case of transmitting data from the base station to the mobile station (terminal),
Of course, it can be applied to the case where data is transmitted from the mobile station to the base station on a high-speed associated channel.

Further, in the above-mentioned embodiment, the present invention is applied to the case of transmitting the control data called the high speed associated channel instead of the voice data. However, if the data is transmitted in the voice data section, various data other than the voice are transmitted. Can also be applied to the transmission of. For example, it can be applied to a case where program data read by various data processing devices such as a computer device connected to a mobile phone is transmitted instead of voice data.

In the above-described embodiment, the voice data of one slot before is used for interpolation, but the voice data of more sections may be used for the interpolation process. For example, when the voice data of one slot after the corresponding section can be used, the voice data of the slots before and after the corresponding section may be used for interpolation.

Further, although the above embodiment is applied to the cellular radio telephone system in which digital data is transmitted by the TDMA system, it is also applicable to a communication device in which voice data is transmitted by another system (the CDMA system or the like). Of course, the present invention can be applied. In this case, the audio data is interpolated in units of one slot in the above embodiment, but it may be interpolated in units suitable for the applied communication method.

[0039]

According to the present invention, when data other than voice data such as control data is transmitted in the voice data section, this data is not output processed as voice data and is erroneously output as voice. Accidents in which noise is output due to processing are prevented, and even when control data is received, the continuity of voice is reliably maintained, and the quality of call voice is maintained.

In this case, when burst data having a slot structure is intermittently received and it is determined that the data is data other than the voice data, all the voice data in at least one slot is replaced with the voice data in other slots. Since the interpolation processing is performed in step 1, the interpolation processing of the burst data transmitted in the slot configuration is favorably performed.

Further, when an error is detected by the error detection code included in the received voice data, the same interpolation process as the interpolation process is performed, so that noise output can be prevented more reliably.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a wireless telephone to which an embodiment of the present invention is applied.

FIG. 2 is a configuration diagram of a main part of one embodiment.

FIG. 3 is an explanatory diagram showing a communication slot configuration according to an embodiment.

FIG. 4 is a flowchart showing a judgment made by a voice processing unit according to an embodiment.

[Explanation of symbols]

 1 wireless telephone 5 data processing unit 6 voice processing unit 10 control unit 52 convolutional decoding circuit 53 control data output terminal 61 voice decoding circuit 62 voice data memory

Claims (3)

[Claims] 1. A receiving device for receiving digital data transmitted in a predetermined data array, and a determining means for determining predetermined bit data included in the received data, and a case in which the determining means determines a first state. , Demodulating the voice data included in the received data,
And a voice data processing means for interpolating the data of a predetermined section included in the received data with other voice data when the state is judged. 2. When the burst data having a slot structure is intermittently received, and the slot data is discriminated by the discriminating means for each slot to discriminate the second state, the voice data processing means has at least one slot within the slot. 2. The receiving apparatus according to claim 1, wherein all the audio data of 1) are interpolated by the audio data of another slot. 3. The receiving apparatus according to claim 1, wherein when an error is detected by an error detection code included in the received voice data, the same interpolation process as the interpolation process is performed by the voice data processing means.