JP2002217875A - Method and device for estimating bit error rate in radio communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a circuit scale without deteriorating a bit error rate estimation characteristic in bit error rate(BER) estimating method/device for evaluating line quality in a radio communication system in which error correction encoding/ decoding are performed. SOLUTION: A signal by which error correction encoding and a rate matching processing are performed is received (1-1). A rate-matching processing (1-2), corresponding to the processing of a transmission side and error correction decoding (1-3), is performed. A special signal which is previously decided is inserted in the reception side rate matching processing (1-2), with respect to a puncture processing for thinning a part of transmission signals on a transmission side. When a bit selection part 1-6 detects a reception signal matched with the special signal, it removes the reception signal from the object of bit error calculation, compares (1-7) decoded (1-3) signals in the other reception signals with the similarly encoded (1-4) signals and calculates the bit error rate (1-9).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for estimating a bit error rate (BER) for evaluating channel quality in a radio communication system for performing error correction codec. The wireless communication system has a transmission power such that a value such as a bit error rate (BER), a frame error rate (FER), or a signal power to interference power ratio (SIR), which indicates line quality, exceeds at least an allowable minimum value. By controlling the transmission and reception of signals, etc., it is possible to maintain a predetermined line quality, suppress unnecessary radio wave emission, effectively use wireless lines, and reduce the power consumption of transmitting and receiving devices. To improve the cost efficiency of the wireless communication system.

However, since the propagation state of a radio channel changes drastically, it is necessary to quickly estimate the channel quality on the receiving side and feed back the estimation result of the channel quality to the transmitting side in order to maintain the predetermined channel quality. There is. Estimation of the bit error rate (BER), one of the important parameters of line quality, is
For example, as disclosed in Japanese Patent Application Laid-Open No. 61-135234, error-correction encoding is performed on information that has been error-correction-decoded by a reception device in the same manner as that of a transmission device, and the re-encoded signal is output. This is performed by regarding the true value of the received signal and comparing it with the actual received signal, and calculating the bit error rate (BER) from the comparison result.

When the above-mentioned bit error rate (BER) estimation is performed, IMT-2000 (International Mobile
Telecommunications 2000) system has a standardized rate matching function, so the bit error rate (BER) in a communication system that performs rate matching processing
The above-described bit error rate (BER) estimation method cannot be directly applied to the estimation.

Here, the rate matching processing will be briefly described. In order to support a flexible multimedia communication service, a user transmits and receives user information without being aware of a bit rate on a wireless line. In other words, even if the bit rate on the wireless link is a predetermined bit rate, the user transmits and receives user information at an arbitrary bit rate that does not match the bit rate.

[0005] For example, if the bit rate of a radio line is 500
If the user information is 400 bits, there is a surplus of 100 bits in the bit rate of the wireless channel. This one
Rather than adding information unrelated to the transmission signal, such as a dummy, to the surplus of 00 bits and transmitting it, 100 bits determined according to a predetermined algorithm are selected from 400 bits to be transmitted. , 40 to send
The selected 100 bits are repeatedly added to 0 bits,
The transmission is performed as 400 bits + 100 bits = 500 bits. This processing is called repetition processing.

On the other hand, when the user information is 600 bits,
The user information is 100 bits more than the bit rate of the wireless line of 500 bits. At this time, 100
Bits have to be decimated. The 100 bits to be decimated are determined from 600 bits to be transmitted according to a predetermined algorithm, and are transmitted with 600 bits−100 bits = 500 bits. This process is called a puncture process.

[0007] When a signal that has been subjected to the above rate matching processing on the transmitting side is received on the receiving side, generally,
For the repetition-processed signal, the corresponding repetition signal is added to one signal to perform decoding.
Conversely, when the puncturing process has been performed, a signal having a predetermined low likelihood of reception (which has little effect on the decoding process) is inserted into the corresponding thinned-out signal and decoded.

As an example, 10-bit user information (X1 to X1
Table 1 below shows an example in which three bits (X1, X5, X9) are added to (0) by repetition processing.

[Table 1]

Table 2 below shows an example in which 10 bits of user information (X1 to X10) are thinned out by puncturing 3 bits (X1, X5, X9).

[Table 2] Here, Z is a specific signal having a low reception likelihood (low frequency and low reception level), and is inserted into a decimated bit position.

In a communication system that performs such a rate matching process, when estimating a bit error rate (BER), if a punctured signal is not excluded from comparison and processed, the bit error rate (BER) BER)
The characteristics of the estimated values are degraded from the actual ones.

This is because, at the time of the puncturing process, a signal having a predetermined low likelihood of reception irrelevant to the received signal is inserted in the receiving apparatus. Therefore, in order to prevent such deterioration of the bit error rate (BER) estimation characteristics, it is necessary to notify the punctured bit position and exclude the signal at the bit position from the bit error rate calculation target.

[0012]

2. Description of the Related Art FIG. 4 shows a configuration of a bit error rate (BER) estimating means of a conventional communication system for performing rate matching. (A) of the figure shows a configuration example of a transmission side apparatus that performs rate matching, and (b) of the figure shows a configuration example of a bit error rate (BER) estimating means in the reception side apparatus.

As shown in FIG. 4 (a), the transmitting side apparatus performs error correction encoding of the user signal by an encoder (ENC) 4-11 and performs repetition processing or puncturing processing by a rate matching (RM) section 4-12. And a signal length corresponding to the number of bit rates of the radio line,
The signal is converted into a radio signal by 3 and transmitted from the antenna.

[0014] As shown in Fig. 4 (b), the receiving side device demodulates the signal received by the antenna by the receiver 4-21, and applies a rate matching (RM) unit 4-22 to the demodulated signal.
Then, the repetition processing or the puncturing processing is performed, the repetition signals are added, or a signal having a low reception likelihood is inserted, and the rate-matched signal is decoded by a decoder (DEC) 4-23 to generate a user signal. I do.

The signal decoded by the decoder (DEC) 4-23 is used to estimate a bit error rate (BER).
The signal is input to an encoder (ENC) 4-24 having the same configuration as that of the encoder (ENC) 4-11 of the transmission side device, and is subjected to error correction coding.
Input to 26.

On the other hand, rate matching (RM) on the receiving side
The demodulated signal subjected to the rate matching process in the unit 4-22 is input to the delay unit 4-25 to be delayed, and is decoded.
After performing timing adjustment with respect to the processing delay of the encoder 4-23 and the encoder (ENC) 4-24, the bit selection unit 4-26
To enter.

Further, a rate matching (RM) unit 4-2
2 is supplied to the bit selection section 4-26. This control signal is a signal indicating that the specific signal insertion processing has been performed on the punctured bit, and is a signal output in one-to-one correspondence with the puncture bit position.

The bit selection section 4-26 is provided with a demodulation signal input through a rate matching (RM) section 4-22 and a delay section 4-25, and a re-encoding output from an encoder (ENC) 4-24. Signal and rate matching (R
M) The signal at the bit position subjected to puncturing is selected and discarded in accordance with the control signal of the unit 4-22, and the two signals not subjected to puncturing are selected and compared with each other.
To -27.

The comparing section 4-27 compares the two demodulated signals and the re-encoded signal to determine whether they match.
The counter 4-28 counts the number of mismatches (number of errors) detected by the comparator 4-27 and the number of signals compared.
The operation unit 4-29 calculates the ratio by dividing the number of errors counted by the counter 4-28 by the number of compared signals, and calculates a bit error rate (BER).

The conventional configuration for estimating a bit error rate (BER) in a communication system that performs rate matching shown in FIG. 4 extracts a signal that has not been subjected to puncturing and calculates the bit error rate (BER). And the bit error rate (BER) is almost equal to the bit error rate (BER).

[0021]

However, the conventional configuration for performing bit error rate (BER) estimation is to transmit a control signal from a rate matching (RM) unit 4-22 to a bit selection unit 4-26, A circuit for notifying the punctured bit position by the control signal is provided.

In the rate matching process, for example, a puncture process may thin out a signal of as many as 2,000 bits from a transmission signal of 10,000 bits. As the data rate increases, the bit position to be subjected to the puncture process is reduced. Therefore, the size of a circuit for notifying a puncturing bit position by the control signal increases, which makes it difficult to reduce the size of a receiver for performing bit error rate (BER) estimation. Was.

According to the present invention, the bit error rate (BE) is compared with the conventional bit error rate (BER) estimation that calculates the bit error rate (BER) by excluding the punctured signal.
R) It is an object of the present invention to provide a bit error rate (BER) estimating method and apparatus capable of greatly reducing the circuit scale without substantially deteriorating the estimation characteristics.

[0024]

The bit error rate estimating method according to the present invention comprises the steps of (1) receiving a signal on which error correction coding and rate matching processing have been performed, and performing rate matching processing and error processing performed on a transmitting side. A bit error rate estimating method in a wireless communication system for performing a rate matching process and an error correction decoding corresponding to an error correction encoding, wherein a signal obtained by performing an error correction encoding on a signal obtained by performing error correction decoding on a signal similar to that on a transmission side is used as a reception signal. In the bit error rate estimation method of calculating the bit error rate by comparing the true value of the received signal and the received signal, the rate matching process of the puncturing process of thinning out a part of the transmitted signal on the transmission side On the other hand, the reception side detects a reception signal that matches a predetermined specific signal to be inserted into the position of the thinned signal from among the reception signals for bit error rate estimation, and Excludes a reception signal matching the signal from the target bit error rate calculation is performed for the bit error rate calculation described above.

(2) It is determined whether or not a specific signal insertion process for the puncture process is performed as the rate matching process on the receiving side. Only when the process for the puncture process is performed, A received signal that matches the specific signal is detected from among the received signals for bit error rate estimation, and the received signal is excluded from the target of the bit error rate calculation. All of the received signals for rate estimation are to be subjected to bit error rate calculation.

Also, the bit error rate estimating apparatus of the present invention
(3) A wireless communication system that receives a signal on which error correction coding and rate matching processing has been performed, and performs rate matching processing and error correction decoding corresponding to the rate matching processing and error correction coding performed on the transmission side. A bit error rate estimating apparatus according to, encoding means for performing the same error correction encoding of the error-corrected decoded signal on the transmission side,
A bit error rate comprising: comparing means for comparing a signal subjected to error correction coding by the coding means with a received signal; and bit error rate calculating means for calculating a bit error rate based on a comparison result of the comparing means. In the estimating device, the reception side matches a predetermined specific signal to be inserted at the position of the thinned signal on the reception side for the rate matching processing of the puncturing processing for thinning out a part of the transmission signal on the transmission side, and estimates the bit error rate. The received signal for detecting from among the received signals for the, including a received signal matching with the specific signal is excluded from the target of the bit error rate calculation is provided with a received signal selection means, the received signal selected by the received signal selection means, This is input to the comparison means.

(4) The rate matching processing means on the receiving side for performing the rate matching processing outputs a control signal indicating whether or not a specific signal insertion processing for the puncturing processing is being performed, and based on the control signal, Only when the processing for the puncturing process is being performed, the received signal selection means selects the received signal for which the bit error rate is to be calculated, sends it to the comparing means, and performs the processing for the puncturing process. If not, all of the received signals are sent to the comparing means as targets for calculating the bit error rate.

[0028]

FIG. 1 shows a receiving side apparatus for performing bit error rate (BER) estimation according to a first embodiment of the present invention. The transmitting side apparatus of the communication system for performing rate matching to which the present invention is applied is the same as that shown in FIG.

In the receiving apparatus shown in FIG. 1, a signal received by an antenna is demodulated by a receiver 1-1, and a repetition process or a puncture process is performed on the demodulated signal by a rate matching (RM) unit 1-2. Is added or a signal with low reception likelihood is inserted, and the rate-matched signal is converted to a decoder (DEC) 1
-3 for error correction decoding to generate a user signal.

Further, the encoder (ENC) 4-11 of the transmission side apparatus converts the signal error-corrected and decoded by the decoder (DEC) 1-3 into an encoder (ENC) 4-11 having the same configuration as that of the encoder (ENC) 4-11 of the transmitting side apparatus for estimating a bit error rate (BER). 1) Input to 1-4, perform error correction coding, and input the error-corrected coded signal to bit selection section 1-6.

On the other hand, a rate matching (RM) section 1-2
The demodulated signal that has undergone the rate matching process in
To adjust the timing with the processing delay of the decoder (DEC) 1-3 and the encoder (ENC) 1-4, and input the result to the bit selection unit 1-6.

The demodulated signal via the rate matching (RM) unit 1-2 and the delay unit 1-5 is input to the bit selection unit 1-6, and is inserted into the punctured signal in the demodulated signal. A predetermined signal having a low reception likelihood is included. However, the signal inserted into the punctured signal by the rate matching (RM) unit 1-2 is a predetermined signal.

Then, the bit selection section 1-6 compares and compares the predetermined signal having a low likelihood with the received signal, determines the matched received signal as a punctured signal, and determines the received signal. Are discarded without selection, and other received signals (output signals of the delay unit 1-5 and output signals of the encoder (ENC) 1-4) are selected and compared.
To supply.

The comparing section 1-7 performs rate matching (R) on the signal selected from the bit selecting section 1-6.
M) The signal received via the unit 1-2 and the delay unit 1-5 is compared with the re-encoded signal output from the encoder (ENC) 1-4 to determine whether they match.

The comparison result of the comparing section 1-7 is input to a counter 1-8. The counter 1-8 compares the number of mismatches (number of errors) detected by the comparing section 1-7 with the number of signals compared. And count. The operation unit 1-9 includes a counter 1-
The number of errors counted by 8 is divided by the number of compared signals to calculate a ratio, thereby calculating a bit error rate (BER).

As described above, according to the present invention, the bit selection unit 1-
In 6, the input received signal is compared with a predetermined signal to be inserted into the punctured signal, and the matching received signal is determined as a punctured signal to thereby determine a rate matching (RM) unit. There is no need to provide a circuit configuration for notifying the punctured bit position by the control signal from 1-2, and the circuit scale can be reduced.

FIG. 2 shows a receiving apparatus for performing bit error rate (BER) estimation according to a second embodiment of the present invention. Also in the second embodiment, the transmitting apparatus that performs rate matching is the same as that shown in FIG.
The receiver 1-1, the rate matching (RM) unit 1-
2. Decoder (DEC) 1-3, Encoder (ENC)
The operations and functions of 1-4 and the delay unit 1-5 are exactly the same as those in the first embodiment of FIG.

In the second embodiment, the encoder (E
The output signals of the NC) 1-4 and the delay unit 1-5 are input to the selector 1-10, respectively. The selector 1-10
Whether the signals input from the encoder (ENC) 1-4 and the delay unit 1-5 are output to the bit selection unit 1-6 according to the control signal output from the rate matching (RM) unit 1-2, Alternatively, it switches over whether to skip the bit selection section 1-6 and output to the comparison section 1-7.

The control signal supplied from the rate matching (RM) unit 1-2 to the selector 1-10 is such that the rate matching process currently performed by the rate matching (RM) unit 1-2 is a process for the puncturing process. It is a signal indicating the type of processing whether the processing is for a repetition.

The selector 1-10 outputs an input signal to the bit selection section 1-6 according to the control signal when the processing for the puncturing process is being performed, and outputs the input signal when the processing for the repetition processing is being performed. The signal is directly output to the comparison unit 1-7.

The bit selection section 1-6 is provided with a puncturing process (insertion of a predetermined signal with low likelihood) only in the rate matching (RM) section 1-2.
The signal is input, the bit selection unit 1-6 compares and compares the predetermined low likelihood signal with the received signal, determines the matched received signal as a punctured signal, and determines the received signal. Discard without selection, other rate matching (RM) unit 1-2 and encoder (ENC)
The signal from 1-4 is selected and supplied to the comparison unit 1-7.

When the puncturing process is performed, the comparison unit 1-7 removes the received signal that matches the predetermined low likelihood signal by the bit selection unit 1-6. When the repetition processing is being performed, the encoder (EN) is used for all the received signals.
C) Compare with the re-encoded signal output from 1-4 to determine whether they match.

The comparison result of the comparing section 1-7 is input to a counter 1-8. The counter 1-8 compares the number of mismatches (number of errors) detected by the comparing section 1-7 with the number of signals compared. And count. The operation unit 1-9 includes a counter 1-
The number of errors counted by 8 is divided by the number of compared signals to calculate a ratio, thereby calculating a bit error rate (BER).

The second embodiment shown in FIG.
Similar to the conventional bit error rate (BER) estimation shown in
Although the control signal output from the rate matching (RM) unit 4-22 is used, the conventional bit error rate (BER) is used.
The control signal in the estimation requires the number of signals representing the punctured bit position, whereas the control signal of this embodiment indicates whether the rate matching process is a process for a puncture process or a process for a repetition process. Since only bit signals are used, the circuit size can be reduced in this embodiment as well.

In the first embodiment, the circuit scale can be reduced compared to the second embodiment because the control signal from the rate matching (RM) unit 1-2 and the selector 1-6 are not used. Although it is possible, the accuracy of the bit error rate (BER) estimation is slightly better in the second embodiment.

In the puncturing process, the receiving side device inserts and decodes a predetermined signal irrelevant to the received signal. However, in the bit error rate (BER) estimation,
When excluding a certain signal that is irrelevant to the received signal, the first embodiment of the present invention excludes all received signals that match the certain signal.

Therefore, if a received signal that should not be excluded but not a signal to be subjected to puncturing coincides with a predetermined signal, all of the matched received signals are excluded in the first embodiment. On the other hand, in the second embodiment, only during a period in which a puncturing process requiring an exclusion process is performed, a reception signal that matches a predetermined signal is excluded. Can reduce the number of received signals,
Accordingly, the accuracy of the bit error rate (BER) estimation is improved.

FIG. 3 shows the bit error rate (B) of the present invention and the conventional example.
ER) shows the estimation results. (A) of the figure shows a comparison of the bit error rate (BER) estimation result between the first embodiment of the present invention and the conventional example, and a curve graph 3-1 shows an actual bit error rate (BER) and a curve graph. 3-2 shows the result of bit error rate (BER) estimation according to the conventional example of FIG. 4, and the curve graph 3-3 shows the result of bit error rate (BER) estimation according to the first embodiment of the present invention.

Here, the bit error rate (BER) estimation result (curve graph 3-2) according to the conventional example of FIG. 4 almost completely matches the actual bit error rate (BER) (curve graph 3-1). . On the other hand, the bit error rate (BER) estimation result (curve graph 3-
In 3), the bit error rate (BER) estimation result is slightly lower because all the received signals that match a certain signal having a low likelihood are excluded, but the error is small in actual operation. A slight error that has little effect.

Since this error can be statistically predicted to some extent in accordance with the frequency of occurrence of a specific signal having a low likelihood, by correcting the error, the actual bit error rate can be estimated. Bit error rate (BER) approximately equal to (BER)
It is possible to obtain an estimate.

FIG. 3B shows a comparison between the bit error rate (BER) estimation results of the second embodiment of the present invention and the conventional example, and the curve graph 3-4 shows the actual bit error rate (BE).
R), curve graph 3-5 shows the result of bit error rate (BER) estimation according to the conventional example of FIG. 4, and curve graph 3-6 shows the result of bit error rate (BER) estimation according to the second embodiment of the present invention. I have.

The curve graph 3-7 shows a bit error rate (BER) estimation result estimated without excluding a signal to be subjected to puncturing without dealing with puncturing, which is described in paragraph 0010 described above. Of the bit error rate (BER) estimation characteristics.

[0053]

As described above, according to the present invention,
In a communication system to which error correction code decoding and rate matching are applied, when a signal predetermined on the receiving side is inserted into a transmission signal thinned out by puncturing processing and decoded, the predetermined signal Is detected, and the received signal is excluded from the calculation of the bit error rate (BER) estimation, thereby obtaining the bit error rate (BE).
R) The circuit scale can be reduced while minimizing the deterioration of the estimation characteristics.

[Brief description of the drawings]

FIG. 1 shows a bit error rate (BE) according to a first embodiment of the present invention.
R) It is a figure which shows the receiving side apparatus which performs estimation.

FIG. 2 shows a bit error rate (BE) according to a second embodiment of the present invention.
R) It is a figure which shows the receiving side apparatus which performs estimation.

FIG. 3 is a diagram showing a comparison between bit error rate (BER) estimation results of the present invention and a conventional example.

FIG. 4 is a diagram showing a configuration of a conventional bit error rate (BER) estimating means in a communication system that performs rate matching.

[Description of Code] 1-1 Receiver 1-2 Rate Matching (RM) Unit 1-3 Decoder (DEC) 1-4 Encoder (ENC) 1-5 Delay Unit 1-6 Bit Selection Unit 1-7 Comparison Unit 1 -8 Counter 1-9 Operation part Reference number 0051795
1/4

Claims (4)

[Claims] 1. A radio that receives a signal on which error correction coding and rate matching processing has been performed, and performs rate matching processing and error correction decoding corresponding to the rate matching processing and error correction coding performed on a transmission side. A method for estimating a bit error rate in a communication system, comprising the steps of: estimating a signal obtained by performing error correction encoding on a signal subjected to error correction decoding as a true value of a received signal, and determining a true value of the received signal and the received signal. In the bit error rate estimating method of calculating the bit error rate by comparing, the rate matching processing of the puncturing processing for thinning out a part of the transmission signal on the transmission side, and the predetermined identification to be inserted at the position of the thinning signal on the reception side A received signal that matches the signal is detected from among the received signals for bit error rate estimation, and a received signal that matches the specific signal is detected from the target of the bit error rate calculation. Bit error rate estimation method in a wireless communication system and performing bit error rate calculation of the disconnect. 2. A method according to claim 1, wherein the rate matching processing on the receiving side is performed to determine whether a specific signal insertion process for a puncture process is being performed, and only when the process for the puncture process is being performed, the specific signal is determined. Is detected from the received signal for bit error rate estimation, and the received signal is excluded from the target of the bit error rate calculation, and if the processing for the puncturing process is not performed, The bit error rate estimation method in a wireless communication system according to claim 1, wherein all of the received signals are subjected to the bit error rate calculation. 3. A radio which receives a signal on which error correction coding and rate matching processing has been performed, and performs rate matching processing and error correction decoding corresponding to the rate matching processing and error correction coding performed on the transmission side. What is claimed is: 1. A bit error rate estimating apparatus for a communication system, comprising: encoding means for performing error correction encoding on a signal subjected to error correction decoding in the same manner as on a transmission side; In a bit error rate estimating apparatus including comparison means for comparing and a bit error rate calculation means for calculating a bit error rate based on a comparison result of the comparison means, a puncturing process for thinning out a part of a transmission signal on a transmission side For the rate matching process, the reception side inserts a reception signal that matches a predetermined specific signal inserted at the thinned signal position on the reception signal for the bit error rate estimation. And a receiving signal selection unit for excluding a reception signal that matches the specific signal from the target of the bit error rate calculation, and inputting the reception signal selected by the reception signal selection unit to the comparison unit. A bit error rate estimating apparatus in a wireless communication system. 4. A rate matching processing means on the receiving side for performing the rate matching processing outputs a control signal indicating whether or not a specific signal insertion processing for the puncturing processing is performed, and based on the control signal, Only when the processing for the processing is being performed, the received signal sorting and selecting means selects the received signal to be subjected to the bit error rate calculation and sends it to the comparing means, and when the processing for the puncturing processing is not performed. 4. The bit error rate estimating apparatus in a wireless communication system according to claim 3, wherein all of the received signals are sent to the comparing means as targets for calculating the bit error rate.