JPH03198545A - Bit error rate measuring device for talking channel - Google Patents

Abstract

PURPOSE:To measure a bit error rate even when a signal sent to a receiver side is not known by adding a check signal to an information signal, coding the result and sending, decoding a reception signal, coding the signal again, comparing it with a signal before decoding and measuring the bit error. CONSTITUTION:A transmitter 1 uses a block coder 12 to add a CRC to an input voice data as an error check signal. Then a convolution coder 13 applies coding and the result is sent from a transmitter 14 via an antenna 15. A receiver 2 allows a Viterbi decoder 23 to receive a demodulated signal on the one hand, and allows a comparator circuit 26 to receive the signal on the other hand. The decoded signal is coded by a convolution coder 25 in the same process as the sender side convolution coder 13 again, a comparator 26 compares the demodulated signal from the receiver 22 with the coded signal from the convolution coder 25 for each hit and counts a different bit number. Then based on the result of discrimination of an error detector 24, the count of the comparator 26 is made valid or invalid and the bit error rate is obtained in the case of the valid count.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a digital mobile communication system, and more particularly to a communication channel bit error rate measuring device that monitors the state of a line using voice signals.

[Conventional technology]

Generally, in a mobile communication system, as shown in the block diagram in FIG.
Communication channel signals are exchanged between the mobile station B and the mobile station B. In order to monitor the state of the line in this traffic channel signal, it is necessary to measure the bit error rate of the traffic channel. Conventionally, in order to measure this bit error rate, a certain predetermined signal is sent and received between wireless base station A and mobile station B, and the bit error rate is measured based on errors in the received signal. .

FIG. 4 is a diagram showing a conventional measuring device for measuring the bit error rate of a communication channel of this type. In the figure, a sending bag W30 has a PN pattern generator 31, and a PN pattern signal generated by this PN pattern generator 31 is transmitted from a transmitter 32 via an antenna 33 using a communication channel. .

On the other hand, the receiving device 40 includes a receiver 42 that receives the signal from the transmitting device 30 via an antenna 41, a comparator 43 that compares the PN pattern with the received signal, and a processor 44 that processes the output of the comparator 43. A comparator 43 compares the received signal and the PN pattern, and a processor 44 calculates the bit error rate, thereby determining the bit error rate of the communication channel.

(Problems to be Solved by the Invention) The conventional bit error rate measuring device described above calculates the bit error rate by comparing the received signal with a known signal on the receiving side, so It is possible to measure a fixed signal such as a voice signal, but it is impossible to measure a fluctuating signal such as a voice signal.Therefore, when measuring the bit rate in a communication channel, it is necessary to measure the voice signal temporarily. There is a problem in that the connection must be disconnected to send and receive fixed signals, and calls are interrupted during this time.

SUMMARY OF THE INVENTION An object of the present invention is to provide a bit error rate measuring device that makes it possible to measure the bit error rate using a fluctuating signal and prevents interruption of calls during measurement.

[Means to solve the problem]

The bit error rate measuring device of the present invention includes a transmitting device that adds a test signal for detecting errors to an information signal, encodes it, and transmits it using a speech channel, and a transmitting device that decodes the received signal and encodes the signal. and a receiving device that re-encodes the encoded signal and compares it with the signal before decoding to measure bit errors.

That is, the transmitting device includes a block encoder that performs block coding and a convolutional encoder that performs convolutional encoding, and the receiving device includes a Viterbi decoder that decodes the received signal and a Viterbi decoder that decodes the signal again. and a comparator that compares the encoded signal with the received signal and counts errors for each bit.

Furthermore, a detector is provided for detecting errors in the signal decoded by the Viterbi decoder, and bit errors in the comparator can be made valid or invalid based on the output of this error detector.

[Effect]

In this bit error measuring device, by adding a verification signal to the audio signal, the bit error rate can be measured using the audio signal, and it is possible to prevent a call using the audio signal from being interrupted during measurement.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention, and here, as shown in FIG. 2, mobile station B receives a communication channel transmitted from radio base station A and measures the bit error rate. An example is shown.

In FIG. 1, a transmitting device 1 provided in a radio base station A as a transmitting side includes a block encoder 12 that adds a verification signal, for example, a CRC, to an audio signal input to an audio signal input terminal 11, and a block encoder 12 that adds a verification signal, for example, a CRC, to an audio signal input to an audio signal input terminal 11. a convolutional code processor 3 for encoding an audio signal including a transmitter 14 . and antenna 1
It is equipped with 5.

On the other hand, the receiving device 2 provided in the mobile station 23 as the receiving side includes an antenna 21, a receiver 22 that demodulates the received signal, and a Viterbi decoder 23 that decodes the demodulated signal.
, an error detector 24 that detects errors in the decoded signal, and a convolutional encoder 25 that re-encodes the decoded signal.
and a comparator 26 for comparing each output of the receiver 22 and the convolutional encoder 25 according to the output of the error detector 24. 27 is an audio signal output terminal.

Note that the convolutional encoder 25 is similar to the convolutional encoder 13 in the transmission bag W1.

According to this configuration, in the transmitting device 1, the block encoder 12 adds a CRC to the input audio data as an error check signal. Next, the signal is encoded by a convolutional encoder 13 and transmitted from a transmitter 14 via an antenna 15.

In the receiving device 2, the receiver 2
The received and demodulated signal at 2 is input to the Leiterbi decoder 23 at the other end. The other one is input to comparator 26.

The signal input to the Leiterbi decoder 23 has errors corrected when it is decoded.

Next, the decoded signal is input to the error detector 24, which determines whether the decoded signal is erroneous. Further, the decoded signal is encoded again by the convolutional encoder 25 in the same process as the convolutional encoder 13 on the transmitting side. Then, in the comparator 26, the demodulated signal from the receiver 22 and the encoded signal from the convolutional encoder 25 are compared bit by bit, and the number of different bits is counted. Then, based on the determination result of the error detector 24, the comparator 2
The count value at step 6 is set as valid or invalid, and the bit error rate is determined only when it is valid.

That is, if there is no interference and there is no error in the received data, the signal output from the Writerbi decoder 23 is error-free, and the error detector 24 determines that there is no error.

Furthermore, when the signal encoded by the convolutional encoder 25 and the signal received by the receiver 22 are compared, the bit error rate is O because there are no different bits.

Next, a writeabi decoder 2 is applied to the data received due to interference etc.
3, if there is an error that can be corrected, the error detector 24 determines that there is no error in the decoded signal, and the counter value of the comparator 26 becomes valid.

The counter value at this time is the number of different bits when the signal from the convolutional encoder 25 and the received signal from the receiver 22 are compared, and the bit error rate is determined from this value.

Further, if error correction of the received data is impossible due to interference or the like, the count value of the comparator 26 becomes invalid and the bit error rate cannot be determined. However, considering the system, this can be avoided by handoff before the above state occurs.

This allows bit errors to be measured using the audio signal without interrupting the call.

FIG. 3 is a block diagram of another embodiment of the present invention, with 50
60 is a transmitting device, and 60 is a receiving device.

In the figure, a transmitting device 50 includes a transmitting signal processor 51 that adds and outputs a test signal for detecting errors in a receiving device 60, a convolutional encoder 52 that encodes the output signal, and a convolutional encoder 52 that encodes the output signal. a transmission signal generator 53 that adds a header to the transmitted signal; and a transmitter 54. and antenna 55
It consists of

The receiving device 60 also includes an antenna 61 . and receiver 62
a header detector 63 that detects a header from a received signal inputted through the
4, a delay device 65 that delays the received signal, a convolutional encoder 66 that re-encodes the decoded signal, and a comparator 67 that compares the output signals of the delay device 65 and the convolutional encoder 66. A bit error measuring device 68 that measures error bits based on the error detection signal from the comparator 67, and a receiving device that evaluates whether or not there is an error in the decoded signal and determines whether or not the information of the bit error measuring device 68 is valid. Signal evaluator 69
It consists of

According to this configuration, in the transmitting device 50, the transmitted signal processor 51 adds a test signal such as a cyclic code to the transmitted signal and outputs the resultant signal. Next, the signal is encoded by a convolutional encoder 52, and a header is added by a transmission signal generator 53 to generate a transmission signal.

The signal is then modulated by a transmitter 54 and transmitted from an antenna 55.

This transmission signal passes through the antenna 61 of the receiving device 60 and is demodulated by the receiver 62. A header detector 63 detected a header from this demodulated signal. Then, the bit error measuring device 68 is reset. Further, the signal decoded by the Writerbi decoder 64 is encoded again by the convolutional encoder 66. A comparator 67 compares this encoded signal with the received signal.
If there is a bit that does not match, a pulse is output.

The delay device 65 delays the other received signal in accordance with the signal delays in the Writerbi decoder 64 and the convolutional encoder 66.

Then, the pulse output from the comparator 67 is measured by a bit error measuring device 68. On the other hand, if the received signal evaluator 69 performs an error check on the decoded signal and there is no error, the value of the bit error measurer 68 is validated and the bit error rate can be determined.

In this embodiment as well, the focus error rate can be measured using the audio signal, and call interruptions can be prevented.

Note that the present invention can be similarly applied to information signals other than audio signals.

(Effects of the Invention) As explained above, the present invention adds a verification signal to an information signal, encodes it, and transmits it, decodes a received signal, and re-encodes the encoded signal before decoding. Since the bit errors are measured by comparing the signal with It is now possible to measure the bit error rate even for such cases, and when audio signals are used, measurement can be performed without interrupting the call.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a block diagram of a bit error rate measuring device of the present invention;
FIG. 2 is a diagram showing the configuration of a mobile communication system, FIG. 3 is a block diagram of another embodiment of the present invention, and FIG. 4 is a block diagram of a conventional bit error rate measuring device. DESCRIPTION OF SYMBOLS 1... Transmitting device, 2... Receiving device, 11... Audio signal input terminal, 12... Block encoder 5.13...
- Convolutional encoder, 14... Transmitter, 15... Antenna, 21... Antenna, 22... Receiver, 23.
... Leitabi decoder, 24 ... error detector, 25 ...
- Convolutional encoder, 26... Comparator, 27... Audio signal output terminal, 30... Transmitting device, 31... PN pattern generator, 32... Transmitter, 40... Receiving device , 41... antenna, 42... receiver, 43...
Comparator, 44... Processing unit, 50... Transmitting device, 51
... Transmission signal processor, 52 ... Convolutional encoder, 5
3... Transmission signal generator, 54... Transmitter, 55...
- Antenna, 60... Receiving device, 61... Antenna, 62... Receiver, 63... Header detector, 64...
... Leiterbi decoder, 65 ... Delay device, 66 ... Convolutional encoder, 67 ... Comparator, 68 ... Bit error measuring device, 69 ... Received signal evaluator, S ... Service area, A: wireless base station, B: mobile station. Figure 2

Claims (1)

[Claims] 1. A transmitting device that adds a test signal for detecting errors to an information signal, encodes it, and transmits it using a speech channel; and a transmitter that decodes the received signal and transmits the encoded signal. A communication channel bit error rate measuring device comprising a receiving device that re-encodes a signal and measures bit errors by comparing the signal with the signal before decoding. 2. The transmitting device includes a block encoder that performs block coding and a convolutional encoder that performs convolutional encoding, and the receiving device includes a Viterbi decoder that decodes the received signal and a convolutional encoder that re-encodes this signal. 2. The communication channel bit error rate measuring device according to claim 1, comprising: an encoder; and a comparator that compares the encoded signal with the received signal and counts errors for each bit. 3. The telephone call according to claim 2, further comprising a detector for detecting errors in the signal decoded by the Viterbi decoder, and in which bit errors in the comparator are validated or invalidated based on the output of the error detector. Channel bit error rate measuring device.