JP2001308759A - Method and device for generating transmission line information, and error correction decoder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable acquiring correct transmission line information even when the influence of a noise is large. SOLUTION: The input signal is applied to a data demodulator 31 and a pilot demodulator 32; to be demodulated. A demodulation signal amplitude sequence rX} is acquired from the output of the data demodulator 31, and a pilot signal sequence p} is acquired from the output of the pilot demodulator 32. The pilot signal sequence p} is applied to an estimation apparatus 33 of transmission line information, and transmission line information LC is acquired as an output of the estimation apparatus 33 of transmission line information. The transmission line information LC on the output of the estimation apparatus 33 of the transmission line information and the demodulation signal amplitude sequence rX} are multiplied in a multiplier 34 to be applied to an error correction decoder 35, then a decoding sequence having few errors can be acquired.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission line information generation method, a transmission line information generation device, and an error correction decoding device applicable to digital mobile communication.

[0002]

2. Description of the Related Art In a decoder involving repetition (for example, a turbo decoder), statistical information (hereinafter, transmission path information) of a received signal is required to reduce correction errors.

When estimating the transmission path information, the following method is used. The transmission path information referred to here is
This is the ratio between the average value of the demodulated signal amplitude and the variance. In the prior art, when the time is t and the demodulated signal amplitude sequence of bit length Nr is {r _x } (1 ≦ x ≦ Nr), the average value m, the variance σ ^2, and the transmission path information L _C are

[0004]

(Equation 1) More required. The transmission path information obtained in this way is multiplied by the received sequence and used as a decoder input.

FIG. 1A shows a demodulated signal amplitude sequence {r _x }, and the demodulated signal amplitude sequence {r _x } is r _{1 to} r _Nr
It is composed of

FIG. 1B shows a transmission path information estimator.
The transmission line information estimator includes an average value calculation circuit 2 for obtaining an average value.
1. A variance value calculating circuit 20 for obtaining a variance value and a multiplier 2
2 is comprised. The demodulated signal amplitude sequence of FIG.
{r _x } is the average value calculation circuit 21 and the variance value calculation circuit 20
Is applied to Then, the average value obtained by the average value calculation circuit 21 is multiplied by the reciprocal of the variance value obtained by the variance value calculation circuit 20 by the multiplier 22, and the output thereof is transmitted to the transmission line information L.
_{Get C.}

FIG. 2 is a conventional configuration diagram of an apparatus for performing soft decision decoding by an error correction decoder using a demodulated sequence generated by a demodulator from a received data sequence.

FIG. 2 shows a demodulator 10 and a sampling circuit 1.
1. It is composed of an error correction decoder 12. The error correction decoder 12 includes a transmission path information estimator 13, a multiplier 14, and a decoder 15.

The received signal is applied to a demodulator 10 and demodulated. The signal demodulated by the demodulator 10 is applied to a sampling circuit 11. As an output of the sampling circuit 11, a demodulated signal amplitude sequence shown in FIG. This demodulated signal amplitude sequence {r _x } is applied to the error correction decoder 12 to obtain a decoded sequence at its output terminal.

The error correction decoder 12 branches the demodulated received signal sequence {r _x } and applies it to the transmission path information estimator 13 as shown in FIG. Transmission path and information L _C is the output of the transmission path information estimator 13, the demodulated signal amplitude sequence {r _x} but,
In the multiplier 14, the signals are multiplied and applied to the decoder 15. As an output of the decoder 15, a decoded sequence with few errors can be obtained.

[0011]

In the prior art, the amplitude and variance of a signal sequence are obtained by using a received signal on which noise is superimposed, so that the noise power greatly varies and the noise power varies with time. In such a case, there is a problem that it is difficult to obtain accurate transmission line information.

The present invention has been made in view of the above problems, and has as its object to obtain accurate transmission path information even when the influence of noise is large.

[0013]

In order to solve the above problems, the present invention employs means for solving the problems having the following features.

According to the first aspect of the present invention, an error-correction-encoded signal and a pilot signal are received, a received signal amplitude and a received signal variance are obtained from a received pilot signal sequence, and the received signal amplitude and the received signal variance are obtained. Calculate the variance ratio,
A transmission path information generation method characterized by generating transmission path information.

According to a second aspect of the present invention, in the transmission path information generating method according to the first aspect, the transmission path information is
It is created using a received pilot signal sequence and a received data sequence of an error-correction-coded signal.

According to a third aspect of the present invention, in the transmission path information generation method according to the first aspect, the transmission path information includes transmission path information calculated from a received data sequence of the received pilot signal and error correction coding. And information obtained by averaging transmission line information calculated from the received data sequence of the obtained signal.

According to a fourth aspect of the present invention, in the transmission line information generation method according to the first or second aspect, the transmission line information sequentially averaged is used as the transmission line information.

According to a fifth aspect of the present invention, there is provided a multiplication means for multiplying a transmission line information generated by the transmission line information generation method according to any one of the first to fourth aspects with a received signal sequence, A transmission path information generating apparatus for decoding an output of a multiplication means.

According to a sixth aspect of the present invention, there is provided means for receiving an error-correction-coded signal and a pilot signal, determining a received signal amplitude and a received signal variance from a received pilot signal sequence, and determining the received signal amplitude and the received signal variance. An error correction decoding device comprising means for calculating transmission signal dispersion ratio and generating transmission path information.

[0020]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 3 is a diagram for explaining the first embodiment.

FIG. 3 shows a demodulator 30 and an error correction decoder 3
5, the received signal is applied to the demodulator 30, the output of the demodulator 30 is applied to the error correction decoder 35, and a decoded sequence is obtained as the output of the error correction decoder 35.

The demodulator 30 includes a data demodulator 31, a pilot demodulator 32, a transmission path information estimator 33, and a multiplier 3
4.

The received signal is, for example, TDM (Time
Division Multiplex)
The TDM reception signal is multiplexed and separated and applied to the data demodulator 31 and the pilot demodulator 32. A demodulated signal amplitude sequence {r _X } is obtained from the output of data demodulator 31, and a pilot signal sequence {p _X } is obtained from the output of pilot demodulator 32. Pilot signal sequence {p _X }
It is applied to the transmission path information estimator 33 as shown in FIG. 1 (B), as the output of the transmission path information estimator 33 to obtain the transmission path information L _C.

That is, the transmitted pilot signal sequence
When {s _X } (1 ≦ x ≦ N _p ) is received and the received signal sequence of the pilot signal obtained by demodulation is {p _X } (1 ≦ x ≦ N _p ),

[0026]

(Equation 2) Thus, transmission path information can be obtained.

The transmission path of the output of the transmission path information estimator 33
Information L_CAnd the demodulated signal amplitude sequence ｛r _X｝ And the multiplier
At 34, they are multiplied and applied to the error correction decoder 35.
As a result, a decoded sequence with few errors can be obtained.

This eliminates the need for estimating the transmission path information in the error correction decoder, so that accurate transmission path information can be obtained even when the influence of noise is large.

FIG. 4 is a diagram for explaining the second embodiment.

FIG. 4 shows a demodulator 40 and an error correction decoder 4.
5, the received signal is applied to the demodulator 40, the output of the demodulator 40 is applied to the error correction decoder 45, and a decoded sequence is obtained as the output of the error correction decoder 45.

The demodulator 40 includes a data demodulator 41, a pilot demodulator 42, a transmission line information estimator 43, and a multiplier 4
4.

Signal sequences from the data demodulator 41 and the pilot demodulator 42 are applied to the transmission path information estimator 43.

The second embodiment is different from the first embodiment.
Pilot signal reception sequence {p _X} In addition to the received
Part of the series of numbers {q_X} (1 ≦ x ≦ N_q)Using,

[0034]

(Equation 3) By obtaining more transmission path information, the accuracy of the transmission path information can be further improved.

FIG. 5 is a diagram for explaining the third embodiment.

FIG. 5 shows a demodulator 50 and an error correction decoder 5.
5, the received signal is applied to the demodulator 50, the output of the demodulator 50 is applied to the error correction decoder 55, and a decoded sequence is obtained as the output of the error correction decoder 55.

The demodulator 50 includes a data demodulator 51, a pilot demodulator 52, a transmission line information estimator 53, and a multiplier 54.
And an averaging circuit 56.

In the third embodiment, an averaging circuit is provided after the transmission path information estimator in the second embodiment. For each of the signal sequences from the data demodulator 41 and the pilot demodulator 42, transmission line information is calculated,
The averaging circuit 56 calculates the average of the transmission line information,
This average value is used as transmission line information.

In the third embodiment, the average of the transmission path information obtained in FIG. 2 or FIG. 3 is used as the average transmission path information, so that the estimation accuracy of the transmission path information can be improved.

FIG. 6 is a diagram for explaining the fourth embodiment.

FIG. 6 shows a demodulator 60 and an error correction decoder 6.
5, the received signal is applied to the demodulator 60, the output of the demodulator 60 is applied to the error correction decoder 65, and a decoded sequence is obtained as the output of the error correction decoder 65.

The demodulator 60 includes a data demodulator 61, a pilot demodulator 62, a transmission path information estimator 63, and a multiplier 64.
And a successive averaging circuit 66.

A signal sequence from one of the data demodulator 61 and the pilot demodulator 62 is applied to the transmission path information estimator 63.

In the fourth embodiment, a sequential averaging circuit is used as the averaging circuit of the third embodiment.

If the transmission path information does not fluctuate greatly in a short time, the transmission path information in the first or second embodiment is used. By calculating the sequential average, it is possible to further improve the accuracy and follow the fluctuation of the transmission line information.

The time constant used for sequential averaging 9-0.9
By setting the number to about 9, it is expected that the estimation accuracy is improved and the effect of tracking the transmission path information is improved.

When the time constant is O.D. In the case of 9, a weighted average is calculated using 0.9 of the previously obtained transmission line information and 0.1 of the newly calculated transmission line information.

FIG. 7 shows an example of the error correction decoding apparatus according to the present invention.

FIG. 7 shows a despreader 70, a RAKE combiner (data) 71, a RAKE combiner (pilot) 72,
The transmission path information estimator 73 receives the SIR (Signal t
o Interface ratio estimator 74, successive averaging circuit 75, TPC command (transmission power control command) generation circuit 76, multiplier 77, and turbo encoder 78
It is composed of

Note that the TPC command is such that the reception SIR is
Generate commands to be constant.

The received pilot signal sequence and the received data sequence are despread by despreader 70 and are synthesized by RAKE combiners 71 and 72. The combined pilot and data sequence are input to the transmission path information estimator 73, and instantaneous transmission path information is calculated. The average transmission line information is generated by successively averaging the instantaneous transmission line information by the sequential averaging circuit 75, and the average transmission line information is multiplied by the multiplier 77.
By multiplying with the demodulated data sequence, reliability information is generated.

[0052]

According to the present invention as described above, the following various effects can be obtained.

By determining the average value and variance of the received signal from the pilot signal sequence and using the ratio as transmission line information, accurate transmission line information can be obtained even when the influence of noise is large. .

Further, by using the received pilot signal sequence and the received data sequence of the error-corrected coded signal as the transmission path information, more accurate transmission path information can be obtained.

Further, by using, as the transmission path information, an average of the transmission path information calculated from the reception data series of the received pilot signal and the transmission path information calculated from the reception data series of the error-correction coded signal. ,further,
Accurate transmission path information can be obtained.

Further, as transmission path information, transmission path information calculated from a reception data series of a received pilot signal or transmission path information calculated from a reception data series of an error correction coded signal is sequentially averaged. Thereby, the accuracy can be further improved, and it is possible to follow the fluctuation of the transmission path information.

Further, since error correction decoding can be performed using accurate transmission path information, an error correction decoding device with a low error rate can be provided.

[0058]

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a demodulated signal amplitude sequence and a transmission path information estimator.

FIG. 2 is a diagram for explaining a conventional method.

FIG. 3 is a diagram for explaining a first embodiment of the present invention.

FIG. 4 is a diagram for explaining a second embodiment of the present invention.

FIG. 5 is a diagram for explaining a third embodiment of the present invention.

FIG. 6 is a diagram for explaining a fourth embodiment of the present invention.

FIG. 7 is a diagram for explaining an error correction decoding device according to the present invention.

[Explanation of symbols]

10, 30, 40, 50, 60 Demodulator 11 Sampling circuit 12 Error correction decoder 13, 33, 43, 53, 63, 73 Transmission path information estimator 14, 22, 34, 44, 54, 64, 77 Multiplier Reference Signs List 15 decoder 20 variance value calculation circuit 21 average value calculation circuit 31, 41, 51, 61 data demodulator 32, 42, 52, 62 pilot demodulator 35, 45, 55, 65 error correction decoder 70 despreader 71 RAKE Combiner (Data) 72 RAKE Combiner (Pilot) 74 Received SIR Estimator 75 Successive Averaging Circuit 76 TPC Command Generation Circuit 78 Turbo Encoder

Continued on the front page F term (reference) 5J065 AA01 AB01 AC02 AE07 AF02 AH03 5K014 AA01 BA02 BA10 EA01 FA11 GA01 HA10 5K046 EE16 EE42 EF46

Claims (6)

[Claims] An error correction coded signal and a pilot signal are received, a received signal amplitude and a received signal variance are obtained from a received pilot signal sequence, and a ratio between the received signal amplitude and the received signal variance is calculated. A transmission path information generation method, wherein transmission path information is generated. 2. The transmission path information generating method according to claim 1, wherein the transmission path information is created using a received pilot signal sequence and a received data sequence of an error-correction-coded signal. Road information generation method. 3. The transmission path information generating method according to claim 1, wherein the transmission path information is obtained from transmission path information calculated from a reception data sequence of the received pilot signal and a reception data sequence of an error-correction-encoded signal. A transmission path information generation method, characterized by using information obtained by averaging calculated transmission path information. 4. The transmission path information generation method according to claim 1, wherein successively averaged transmission path information is used as said transmission path information. 5. A multiplying means for multiplying transmission line information generated by the transmission line information generating method according to claim 1 with a received signal sequence, and decoding an output of said multiplying means. A transmission path information generation device, characterized in that: 6. A means for receiving an error correction coded signal and a pilot signal, obtaining a received signal amplitude and a received signal variance from a received pilot signal sequence, and calculating a ratio between the received signal amplitude and the received signal variance. An error correction decoding device comprising means for generating transmission path information.