JP2007300359A - Wireless communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique that dispenses with descrambling and scrambling in a repeater of a wireless communication system and also enables a reception side to suppress noise due to an error. <P>SOLUTION: The wireless communication system communicates a data packet containing audio data by radio from a wireless transmitting station to a wireless receiving station through a wireless relay station, wherein the wireless relay station, when detecting an error in the received data packet, is operative to incorporate error detection data in the data packet and transmit the packet to the wireless receiving station, and the wireless relay station, when detecting the error detection data being incorporated in the received data packet, performs audio signal processing after replacing the data packet with a data packet in which soundless data are incorporated. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a technique for wirelessly communicating data such as digitized audio signals via a repeater.

Conventionally, in a wireless communication system using a packet communication technique, a repeater is sometimes used to expand a communicable range.
In such a digital wireless communication system, various techniques have been proposed and adopted in order to cope with the occurrence of errors in the communication process.
For example, in addition to adopting an encoding method with high error recovery capability, if the reception side cannot process normally, the transmission side automatically resends the data or the transmission side is the same There is a method (see Patent Document 1) in which a plurality of data packets incorporating data are continuously transmitted, and a data packet without error is selected from the received plurality of data packets and processed.

JP-A-11-261465

  If the error cannot be recovered even by such a method, in audio communication, if the digital signal containing the error is decoded into an analog signal and output from a speaker or earphone, it may be output as a loud noise. There is sex.

  Accordingly, the present invention has been made for the purpose of providing a wireless communication system capable of outputting an audio signal in which noise due to an error is suppressed during reception.

A wireless communication system according to the present invention includes:
In a wireless communication system for performing wireless communication of data packets incorporating voice data from a wireless transmission station to a wireless reception station via a wireless relay station,
When the radio relay station detects an error in the received data packet, the radio relay station is configured to incorporate error detection data in the data packet and transmit the error detection data to the radio reception station.
When the wireless reception station detects that error detection data is incorporated in the received data packet, the wireless reception station performs voice signal processing by replacing the data packet with a data packet incorporating silence data. To do.
The radio relay station according to claim 2 is:
A radio relay station used in the radio communication system according to claim 1,
When it is detected that error detection data is incorporated in the received data packet, the data packet is provided with a replacement transmission means for transmitting the data packet by replacing it with a data packet incorporating silence data. .
The radio receiving station according to claim 3 is:
A radio receiving station used in the radio communication system according to claim 1,
When it is detected that error detection data is incorporated in the received data packet, a replacement receiving means for replacing the data packet with a data packet incorporating silence data is provided.
The wireless relay station of claim 4 is:
In a radio relay station used in a radio communication system that performs radio communication of data packets in which audio data is incorporated into a radio reception station from a radio transmission station via a radio relay station,
In the case where an error is detected in the received data packet, a replacement transmission means is provided for transmitting the data packet by replacing it with a data packet incorporating silence data.
The radio receiving station according to claim 5 is:
A wireless reception station used in a wireless communication system for performing wireless communication of data packets in which audio data is incorporated into a wireless reception station via a wireless relay station from a wireless transmission station,
When an error is detected in the received data packet, replacement receiving means is provided for replacing the data packet with a data packet incorporating silence data.

According to the wireless communication system of the present invention,
In the wireless relay station, when an error is detected in the received data packet, the error detection data is incorporated into the data packet and transmitted to the wireless reception station. In the wireless reception station, the error detection data is included in the received data packet. When it is detected that the data packet has been incorporated, the data packet is replaced with a data packet incorporating silence data, and the audio signal processing is performed, so that noise noise due to the error is not output and a noise suppression effect is obtained. is there.
In addition, the wireless relay station does not need to perform processing to release or generate scramble, reducing the data processing burden.
The radio relay station according to claim 2 is:
When an error is detected in the received data packet, the error detection data is incorporated into the data packet and transmitted, so that the above effect can be obtained by using it in the wireless communication system.
The radio receiving station according to claim 3 is:
When it is detected that error detection data is incorporated in the received data packet, the data packet is processed by replacing it with a data packet incorporating silence data. An effect can be obtained.
The wireless relay station of claim 4 is:
If an error is detected in the received data packet, the data packet is replaced with a data packet that incorporates silence data.
Even if it is not used in the wireless communication system, the noise receiving effect is not obtained at the wireless receiving station because the noise sound due to the error is not output.
The radio receiving station according to claim 5 is:
When an error is detected in the received data packet, the data packet is processed by replacing it with a data packet incorporating silence data.
Noise noise due to the error is not output, and a noise suppression effect is obtained.

Hereinafter, a radio communication system according to the present invention will be described in detail with reference to the drawings showing embodiments thereof.
FIG. 1 is an operation block diagram of the radio relay station of the embodiment,
This wireless relay station 1
Received data demodulation means 11 for receiving and demodulating a signal from a wireless transmission station to be relayed;
Error detection means 12 for setting an error flag as error detection data when an error such as packet loss is detected in the demodulated data packet of received data;
Data construction means 13 for constructing transmission data from the data packet subjected to error flag processing;
Transmission data modulation means for modulating and transmitting the constructed transmission data.
In the data packet, audio data obtained by digitally processing an analog audio signal is incorporated as data to be transmitted.
The wireless relay station 1 also has a configuration in which a signal from a network such as the Internet, an intranet, a packet switching network, or a LAN is received and input to a network interface provided in the wireless relay station 1 by wire. A signal input from the network is demodulated and input to the error detection means 12 in a state where the scramble is not released.
The received data demodulating means 11 is configured to demodulate the received signal and input a signal that has not been descrambled to the error detecting means 12, and the error detecting means 12 An error in a state where descrambling is not released is detected.

The error detection means 12 detects the occurrence of an error as a packet loss in demodulated received data, or a situation where the data packet cannot be correctly relayed as voice data due to noise.
The error detection unit 12 sets an error flag as error detection data in the data packet when an error occurrence as described above is detected, and does not set an error flag when no error occurrence is detected. Error flag processing is performed.

FIG. 2 is an operation block diagram of the radio receiving station of the embodiment,
This radio receiving station 2
Received data demodulating means 21 for demodulating the received signal;
Descrambling means 22 for descrambling the demodulated received data;
When an error such as a codec error that cannot be recovered in the data packet of the received data is detected, or when it is detected that an error flag is set as error detection data in the data packet, the silent data generating means 23 Replacement means 24 for replacing with a data packet containing silence data generated separately;
A codec decoding means 25 for decoding the error-free data packet or the data packet replaced with silence data, and decoding the audio data incorporated in the data packet into a low-frequency audio signal according to a predetermined codec;
Low frequency amplification means 26 for amplifying the decoded low frequency audio signal;
And an audio output means 27 such as a speaker for outputting the amplified low frequency audio signal.
The silent data generating means 23, the replacing means 24, the codec decoding means 25, the low frequency amplifying means 26, and the acoustic output means 27 constitute a replacement receiving means described in the claims.
The replacement means 24 is configured to detect an error in a state where descrambling is released for each frame.
The silence data generating means 23 may be one in which silence data corresponding to the length of one frame is stored.

Since the wireless relay station 1 configured as described above does not require scramble processing, silence data generation processing, or replacement processing, the load on data processing is reduced, resulting in quick processing. Become.
And, in the radio receiving station 2 configured as described above,
When an unrecoverable error such as a codec error is detected in the processing of the descrambled data packet, the data packet is replaced with a data packet containing silence data separately generated by the silence data generation means 23, and the subsequent processing. I do. Therefore, there is a risk of generating loud sound noise when audio data including an error is reproduced, but since it has been replaced with silence data, clear noise suppression is possible.
Further, when a data packet in which an error that cannot be recovered such as a packet loss is detected in the wireless relay station 1 instead of a codec error, the replacement unit 24 detects that an error flag is set. Even when this error flag is detected, the data packet is replaced with a data packet including silence data separately generated by the silence data generation means 23, and the subsequent processing is performed. Therefore, since the voice data portion of the data packet including the error is replaced with silence data, it is possible to suppress noise clearly.

If an error such as a codec error that cannot be recovered in the data packet of the received data received for relay is detected in the wireless relay station, it is replaced with a data packet containing silence data generated separately and transmitted. Alternatively, a configuration as shown in FIG.
The radio relay station 100 shown in FIG.
Received data demodulation means 101 for receiving and demodulating a signal from a wireless transmission station to be relayed;
Descrambling means 102 for descrambling the demodulated received data;
When an unrecoverable error such as a packet loss is detected, a replacement unit 104 that replaces the silence data separately generated by the silence data generation unit 103;
Scramble generating means 105 for generating scramble;
Data construction means 106 for constructing transmission data from a data packet incorporating the silent data;
Transmission data modulation means 107 for modulating and transmitting the constructed transmission data.
The silent data generation means 103, the replacement means 104, the scramble generation means 105, the data construction means 106, and the transmission data modulation means 107 constitute the replacement transmission means described in the claims.
The radio relay station 100 also has a function of receiving a signal from a network such as the Internet, an intranet, a packet switching network, or a LAN and relaying the signal to the radio receiving station 200. In this case, a signal from the network is input to a network interface provided in the wireless relay station 100 by wire.
The silence data generated by the silence data generation means 103 is processed with a scramble code analyzed in advance.

In this way, in the radio relay station 100, after the descrambling is once canceled, the erroneous data packet is replaced with the data packet replaced with the silence data, and the scramble is generated and relayed and transmitted. An excellent noise suppression effect can be obtained even if the wireless receiving station is not configured as described above.
When a data packet relayed by another wireless relay station is received and it is detected that an error flag as error detection data is set in the data packet, relay transmission is performed as it is.
In addition, when a data packet relayed by another radio relay station is received and it is detected that an error flag as error detection data is set in the data packet, the data packet is generated separately. Replacement transmission means may be provided which replaces and transmits data packets incorporating silence data.
The standard for error detection of a radio frame adopted in a conventional radio receiving station is that the synchronization word part of the communication channel part is continuous for two frames or more, so about 160 ms of undefined voice corresponding to two frames was output. .
In the wireless communication system of the present application, since the wireless relay station determines whether or not there is an error for each frame, indefinite sound is not output.

In addition, when an error such as a codec error that cannot be recovered is detected in the received data at the radio receiving station, it is possible to obtain a noise suppression effect by processing and reproducing the data by replacing with silence data generated separately. Good.
A configuration example of such a radio receiving station is shown in FIG.
The illustrated radio receiving station 200 is:
Received data demodulating means 201 for demodulating the received signal;
Descrambling means 202 for descrambling the demodulated received data;
When an error such as a codec error that cannot be recovered in the received data is detected, a replacement unit 204 that replaces the silence data separately generated by the silence data generation unit 203;
Codec decoding means 205 for decoding low-frequency audio signals according to a predetermined codec;
Low frequency amplification means 206;
And an audio output means 207 such as a speaker.
The silent data generating means 203, the replacing means 204, the codec decoding means 205, the low frequency amplifying means 206, and the sound output means 207 constitute a replacement receiving means described in the claims. Yes.

By providing the replacement means 204 and the silent data generation means 203, there is an inconvenience that loud sound noise is output from the sound output means 207 such as a speaker even if the received digital signal contains an error that cannot be recovered. By avoiding this, an excellent noise suppression effect can be obtained.
Even if the radio receiving station is a relay signal from a conventional radio relay station that does not include an error detection unit like the radio relay station shown in FIG. Since the processing is replaced, an excellent noise suppression effect can be obtained.

The wireless communication system of the present invention can also be used by connecting to a wide area network such as the Internet or WAN. In this case, any one of the radio relay stations may be connected to the network.

FIG. 3 shows a configuration example of a wireless communication format in the wireless communication system of the first embodiment.
FIG. 3A shows a basic configuration example of a data frame transmitted after the PTT switch of the wireless transmission station is pressed.
As shown in the figure, this data frame includes a preamplifier unit including data for timing on the transmission side and the reception side, a synchronization burst unit including data for establishing synchronization, audio data, and the like. And a communication channel section including data to be communicated.
The synchronization burst unit includes information such as communication mode identification information for identifying voice communication or non-voice communication.

FIG. 3B shows the signal format of the communication channel section in the data frame.
The communication channel unit communicates with a synchronization word unit including a bit string used for frame synchronization, a wireless information channel including various identification information such as an error flag, and a low-speed control channel unit including control information. It includes a high-speed control channel section that includes audio data and digital data to be processed.

As shown in FIG. 3 (c), the wireless information channel section includes wireless channel structure identification information for identifying a synchronization burst signal or a communication channel signal,
An error flag indicating whether an error has been detected in the data packet; and
Functional channel identification information, communication mode identification data, and the like are included.

In the case of the wireless communication format configured as described above, in the wireless relay station 1, when the error detection unit 12 detects an error in the data packet, the error flag shown in FIG. 1 "and the flag is set. If no error is detected in the data packet, the initial value remains “0” and the flag cannot be set.
A data frame in such a wireless communication format is transmitted from the wireless relay station 1.

  When the radio receiving station 2 receives and demodulates the data packet, and the replacement unit 24 processes the descrambled data packet, if an error in processing such as a codec error is detected, the voice data of the data packet is received. The portion is replaced with silence data generated by the silence data generation means 23. Also, when the replacement unit 24 detects that the error flag of the wireless information channel portion in the descrambled data packet is set to “1”, the voice data portion of the data packet is silenced. Replace with the silence data generated by the data generation means 23.

Therefore, even a data packet that originally contained an error is replaced with silence data, so that the sound output from the sound output means 27 becomes silent, and a clear noise suppression effect is obtained.
The standard for error detection of a radio frame employed in a conventional radio receiving station is that the synchronization word part of the communication channel part is continuous for two frames or more, so approximately 160 ms of undefined voice corresponding to two frames was output. .
In the wireless communication system of the present application, since the wireless relay station determines whether or not there is an error for each frame, indefinite sound is not output.

It is a block diagram of the radio relay station of embodiment of the radio | wireless communications system concerning this invention. It is a block diagram of the radio receiving station of the said radio | wireless communications system. 1 is a diagram illustrating a data configuration in a wireless communication system according to a first embodiment. It is a block diagram of the radio relay station of another embodiment. It is a block diagram of the radio | wireless receiving station of another embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Radio relay station 11 Reception data demodulation means 12 Error detection means 13 Data construction means 14 Transmission data modulation means 2 Radio reception station 21 Reception data demodulation means 22 Scramble release means 23 Silence data generation means 24 Replacement means 25 Codec decoding means 26 Low frequency Amplifying means 27 Acoustic output means 23, 24, 25, 26, 27 Replacement reception means 100 Wireless relay station 103, 104, 105, 106, 107 Replacement transmission means 200 Radio reception station 203, 204, 205, 206, 207 Replacement reception means

Claims (5)

In a wireless communication system for performing wireless communication of data packets incorporating voice data from a wireless transmission station to a wireless reception station via a wireless relay station,
When the radio relay station detects an error in the received data packet, the radio relay station is configured to incorporate error detection data in the data packet and transmit the error detection data to the radio reception station.
When the wireless reception station detects that error detection data is incorporated in the received data packet, the wireless reception station performs voice signal processing by replacing the data packet with a data packet incorporating silence data. Wireless communication system. A radio relay station used in the radio communication system according to claim 1,
A radio relay station comprising error detection means for transmitting error detection data in the data packet when an error is detected in the received data packet. A radio receiving station used in the radio communication system according to claim 1,
A radio receiving station comprising replacement receiving means for replacing the data packet with a data packet incorporating silence data when it is detected that error detection data is incorporated in the received data packet . In a radio relay station used in a radio communication system that performs radio communication of data packets in which audio data is incorporated into a radio reception station from a radio transmission station via a radio relay station,
A radio relay station comprising replacement transmission means for transmitting, when an error is detected in a received data packet, replacing the data packet with a data packet incorporating silence data. A wireless reception station used in a wireless communication system for performing wireless communication of data packets in which audio data is incorporated into a wireless reception station via a wireless relay station from a wireless transmission station,
A radio receiving station comprising replacement receiving means for replacing a data packet with a data packet incorporating silence data when an error is detected in the received data packet.

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