JPH08149176A - Demodulator - Google Patents

Abstract

PURPOSE: To provide a demodulator whose circuit scale is not considerably increased even in the data transmission system of the multi-carrier transmission system requiring many numbers of subcarriers by providing a means conducting interpolation estimate processing in time division or in symbol number division so as to process the interpolation estimate section in divisions. CONSTITUTION: When a reception signal is fed to an input terminal 1, a signal separate section 2 separates the reception signal into a pilot symbol and a data symbol for each subcarrier. Each pilot symbol distortion calculation section 3 calculates fading distortion in the pilot symbol and gives the calculated distortion to an interpolation estimate section 10. The interpolation estimate section 10 uses a division control section 8 to control a fading distortion amount for each subcarrier received by each pilot symbol distortion calculation section 3 and to interpolate and estimate the fading distortion in the data symbol in time division and the interpolation estimate result is fed to a storage section 7 and a fading compensation section 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a demodulator of a data transmission device which transmits data by a multicarrier transmission system.

[0002]

2. Description of the Related Art FIG. 2 shows a block configuration of a fading compensation circuit in a conventional demodulator. In the figure, when the received signal subjected to synchronous detection or quasi-synchronous detection is supplied to the input terminal 1, the signal separation unit 2 converts the received signal into pilot symbols and data symbols for each subcarrier in the multicarrier transmission system. Perform separation. The separated pilot symbols are divided into pseudo pilot symbol setting section 5 and pilot symbol distortion amount calculating section 3 for each subcarrier.
On the other hand, the data symbols are given to the fading compensation unit 6. Next, in the pseudo pilot symbol setting unit 5, pseudo pilot symbols are set based on the pilot signals in the subcarriers of the adjacent channels, and the setting result is the pilot symbol distortion provided for each subcarrier. It is input to the amount calculation unit 3. Each pilot symbol distortion amount calculation unit 3 calculates the fading distortion amount in the pilot symbol and supplies the calculated distortion amount to the interpolation estimation unit 4 provided for each subcarrier. Each interpolation estimation unit 4 interpolates and estimates the fading distortion amount in the data symbol based on the distortion amount input from each pilot symbol distortion amount calculation unit 3, and supplies the interpolation estimation result to the fading compensation unit 6. For the data symbols, the fading compensation unit 6 for each subcarrier uses the interpolation estimation result from each interpolation estimation unit 4 to perform fading compensation on the data symbols and remove the fading distortion from the reproduced data symbols. Is output to the output terminal 9.

This conventional example will be described below with reference to FIGS. FIG. 3 shows an example of the basic slot configuration of each subcarrier. As shown in FIG. 3, 1 to N (N is 2
In each subcarrier of (above integer), the number of pilot symbols whose amplitude and phase are known is M per slot.
(M is an integer of 1 or more) are inserted, and the pilot symbols are inserted alternately between adjacent subcarriers. The head pilot symbol P ₁ is located on the same time at the head of the slot for each subcarrier as a slot synchronization symbol. The pilot symbols separated by the signal separation unit 2 of FIG. 2 are input to the pseudo pilot symbol setting unit 5 of FIG.
As shown in, interpolation estimation is performed by using pilot symbols of other subcarriers, and pseudo pilot symbols are set. This pseudo pilot symbol and the pilot symbol actually received, for each subcarrier,
By inputting to pilot symbol distortion amount calculation section 3 shown in FIG. 2, the slot configuration shown in FIG. 3 has the same pilot symbol insertion period for all subcarriers as shown in FIG.

In each bilot symbol distortion amount calculation unit 3 shown in FIG. 2, the fading distortion amount C _Pn in the pilot symbol for each subcarrier is calculated, and the calculated distortion amount is respectively supplied to the interpolation estimation unit 4 in the same figure. input. Next, in each of the interpolation estimation units 4, as shown in FIG.
The distortion amount C _n of each data symbol is interpolated and estimated based on the fading distortion amount C _P1 to _M calculated for each subcarrier, and the interpolated and estimated distortion amount is given to the fading compensation unit 6 for each subcarrier. Each fading compensation unit 6 performs fading compensation of the data symbol based on the distortion amount estimated by interpolation, and outputs the reproduced data symbol from which the fading distortion is removed.

[0005]

In the above-described conventional interpolation estimation unit, since the pseudo pilot symbols are inserted as shown in FIG. 5, the configuration in the interpolation estimation unit is the same, In order to perform continuous processing as shown in 6,
There is a drawback that a plurality of interpolation estimators as many as the number of subcarriers are required, and the circuit scale increases remarkably as the number of subcarriers increases. It is an object of the present invention to eliminate this drawback and to provide a demodulator in which the circuit scale does not significantly increase even in a data transmission system of a multicarrier transmission system having a large number of subcarriers.

[0006]

In order to achieve the above object, the present invention provides a means for performing time division or symbol number division of the interpolation estimation processing, and the processing of the interpolation estimation unit is divided. It was done like this. Further, a storage means is provided for storing the interpolated estimation result obtained by the division processing, the required interpolated estimation result is taken out at any time, and the continuation of the interpolated estimation is performed, so that the interpolated estimation unit provided for each subcarrier can be It is common.

[0007]

As a result, since the interpolation estimating unit is provided with the division control means and the storing means, the interpolation estimating unit can be shared.
The circuit scale can be reduced.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of one embodiment of the present invention will be described below with reference to FIG. When the received signal subjected to the synchronous detection or the quasi-synchronous detection is supplied to the input terminal 1, the signal separation unit 2
In, the received signal is separated into pilot symbols and data symbols for each subcarrier. The separated pilot symbols are divided into pseudo pilot symbol setting section 5 and pilot symbol distortion amount calculating section 3 for each subcarrier.
On the other hand, the data symbols are given to the fading compensation unit 6. Pseudo pilot symbol setting section 5
At, a pseudo pilot symbol is set using pilot symbols of adjacent subcarriers, and the setting result is input to pilot symbol distortion amount calculation section 3 provided for each subcarrier. Each pilot symbol distortion amount calculation unit 3 calculates the fading distortion amount in the pilot symbol, and supplies the calculated distortion amount to the interpolation estimation unit 10.

In the interpolation estimation unit 10, the division control unit 8 controls the fading distortion amount for each subcarrier input from each pilot symbol distortion amount calculation unit 3, and the fading distortion amount in the data symbol is interpolated and estimated in a time division manner. ,
The interpolation estimation result is supplied to the storage unit 7 and the fading compensation unit 6. On the other hand, for the data symbol, the fading compensation unit 6 for each subcarrier performs fading compensation on the data symbol using the interpolation estimation result from the interpolation estimation unit 10, and a reproduced data symbol from which fading distortion has been removed is output terminal 9 Output to.

Next, the interpolation estimation processing in one embodiment of the present invention will be described in more detail with reference to FIGS. 7 and 8. In the interpolation estimation unit 10 shown in FIG. 1, the fading distortion amount of the data symbol is interpolated and estimated with reference to the fading distortion amount of the pilot symbol calculated by the pilot symbol distortion amount calculation unit 3 for each subcarrier. In this interpolation estimation processing, interpolation estimation for one slot is performed by time division or symbol division, and as shown in FIG.
At the start of the processing of the corresponding divided slot, the interpolation estimation result of the previous corresponding divided slot is retrieved from the storage unit and the interpolation estimation processing is performed. At that time, the interpolation estimation results of the divided slots other than the corresponding slot in the interpolation estimation unit are input to the storage unit and the fading compensation unit. The interpolation estimation result is stored in the storage unit until the processing of the corresponding divided slot is started again, and the extraction processing is performed at the start of the processing, whereby the interpolation estimation can be performed without losing the continuity of the slot. The interpolation estimation result given to the fading compensation unit is used for fading compensation in the data symbol.

FIG. 8 shows an example of time division in the above processing. As shown in FIG. 8, one slot is divided into X and 1
Let T be the processing time for division. The process is performed for each subcarrier (1, 2 to XN + N) as shown in the figure, and after the interpolation estimation process is completed, the interpolation estimation result is supplied to the fading compensation unit 6 and the storage unit 7 shown in FIG. Division processing is performed. The interpolation estimation method of the data symbol distortion amount and the fading compensation method are the same as those in the conventional example.

[0012]

According to the present invention, by dividing the processing in the interpolation estimation unit, the interpolation estimation unit can be shared and the circuit scale of the demodulator can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing the overall configuration of the present invention.

FIG. 2 is a block diagram showing a configuration of a conventional example.

FIG. 3 is a basic slot configuration diagram.

FIG. 4 is a diagram showing setting of pseudo pilot symbols.

FIG. 5 is a slot configuration diagram in which pseudo pilot symbols are inserted.

FIG. 6 is a diagram showing fading distortion amount interpolation estimation of a data symbol.

FIG. 7 is a diagram showing a relationship of evacuation storage.

FIG. 8 is a diagram showing an example of division of an interpolation estimation process.

[Explanation of symbols]

 1 Input Terminal 2 Signal Separation Section 3 Pilot Symbol Distortion Amount Calculation Section 4, 10 Interpolation Estimating Section 5 Pseudo Pilot Symbol Setting Section 6 Fading Compensation Section 7 Storage Section 8 Division Control Section 9 Output Terminal

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Claims (4)

[Claims] 1. A demodulator of a data transmission device using a multicarrier transmission method, wherein a fading distortion amount is calculated using pilot symbols inserted at a predetermined cycle between data symbol sequences transmitted on each subcarrier. Means, interpolation estimating means for interpolating and estimating the fading distortion amount in the data symbol based on the calculated fading distortion amount of the pilot symbol, and compensating means for performing fading compensation according to the estimated fading distortion amount. In the demodulator, it is provided with a setting means for setting a pseudo pilot symbol from pilot symbols of adjacent subcarriers, and an interpolation estimation means for performing the interpolation estimation processing of the fading distortion amount by time division or symbol number division. Characteristic demodulator. 2. The demodulator according to claim 1, wherein the interpolation estimating means is means for interpolating and estimating the fading distortion amount of the data or the received signal itself with reference to the fading distortion amount of the pilot symbol or the received signal itself. A demodulator characterized in that. 3. The demodulator according to claim 1, wherein the setting means for setting the pseudo pilot symbol uses a fading distortion amount of a pilot symbol of another subcarrier other than the own subcarrier or the received signal itself. A demodulator which is means for performing interpolation estimation and setting a pseudo pilot symbol. 4. The demodulator according to claim 1, wherein the interpolation estimation means stores the interpolation estimation result in a time division manner or a symbol number division manner in which the interpolation estimation processing of the fading distortion amount of the data symbol is performed. And a storage means for storing the demodulator.