JP2002111561A - Radio-receiving system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio-receiving system, in which communication quality is enhanced by reducing influences of estimation errors in receiving and responding vectors. SOLUTION: Based on a signal outputted from a signal-processing means for subjecting signals received at a plurality of antennas to prescribed signal- processing, signal components individually corresponding to a plurality of users are extracted. Based on the extracted signal components, a plurality of receiving and answering vectors are estimated, from the inside slots in propagation paths from specific terminals, and, using the plurality of the receiving and responding vectors, an answering vector signal for use in replica signal calculation is calculated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio receiving system, and more particularly to a PDMA (Path Division Multiple Tiple Acquisition).
cess), CDMA (Code Division Multiple Access)
The present invention relates to a wireless receiving system using a communication method such as this, which can remove an interference signal component caused by another user from a received signal.

[0002]

2. Description of the Related Art In a mobile communication system such as a portable telephone, which has been rapidly developing in recent years, various transmission channel allocation methods have been proposed for effective use of frequency. Has been

FIG. 27 shows a frequency division multiple access (Frequency Multiple Access).
FIG. 2 is an arrangement diagram of channels in various communication systems of Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), and PDMA.

First, referring to FIG. 27, FDMA, TD
MA and PDMA will be briefly described. FIG.
(A) is a diagram showing FDMA, in which different frequencies f1 are used.
The analog signals of the users 1 to 4 are frequency-divided and transmitted by radio waves of f4 to f4, and the signals of the users 1 to 4 are separated by the frequency filter.

In the TDMA shown in FIG. 27B,
Each user's digitized signal has a different frequency f1
The signals of each user are separated by a frequency filter and a time synchronization between the base station and each user mobile terminal device by radio waves of .about.f4 and transmitted in a time-division manner for each fixed time (time slot).

On the other hand, in recent years, a PDMA system has been proposed in order to increase the frequency use efficiency of radio waves due to the spread of portable telephones. This PDMA system is shown in FIG.
As shown in (1), one time slot at the same frequency is spatially divided to transmit data of a plurality of users. In this PDMA, the signal of each user is separated using a frequency filter, time synchronization between a base station and each user mobile terminal device, and a mutual interference canceling device such as an adaptive array.

The principle of operation of such an adaptive array radio base station is described in, for example, the following document.

B. Widrow, et al .: “Adaptive Antenna
Systems, ”Proc. IEEE, vol.55, No.12, pp.2143-2159
(Dec. 1967). SP Applebaum: "Adaptive Arrays", IEEE Tran
s. Antennas & Propag., vol.AP-24, No.5, pp.585-598
(Sept. 1976). OL Frost, III: “Adaptive Least Squares Optimiz
ation Subject to Linear Equality Constraints, ”SE
L-70-055, Technical Report, No.6796-2, Informatio
n System Lab., Stanford Univ. (Aug. 1970). B. Widrow and SD Stearns: “Adaptive Signal Pr
ocessing, "Prentice-Hall, Englewood Cliffs (198
Five). RA Monzingo and TW Miller: “Introduction t
o Adaptive Arrays, ”John Wiley & Sons, New York
(1980). JE Hudson: “Adaptive Array Principles,” Peter
Peregrinus Ltd., London (1981). RT Compton, Jr .: “Adaptive Antennas-Concept
s and Performance, ”Prentice-Hall, Englewood Cliff
s (1988). E. Nicolau and D. Zaharia: “Adaptive Arrays,” E
lsevier, Amsterdam (1989).

FIG. 28 is a schematic diagram conceptually showing the operation principle of such an adaptive array radio base station. In FIG. 28, one adaptive array radio base station 2
01 includes an array antenna 202 composed of n antennas # 1, # 2, # 3,..., #N, and represents a range where the radio waves reach as a first area 203. On the other hand, a range in which radio waves of another adjacent wireless base station 206 can reach is represented as a second area 207.

[0010] In the area 203, the mobile phone 204 as the terminal of the user A and the adaptive array radio base station 201
The transmission and reception of radio signals are performed between
5). On the other hand, in the area 207, transmission and reception of radio signals are performed between the mobile phone 208 as the terminal of the other user B and the wireless base station 206 (arrow 209).

Here, the mobile phone 2 of the user A happens to be
04 radio signal frequency and user B's mobile phone 208
When the frequency of the radio signal of the user B is equal, the radio signal from the mobile phone 208 of the user B becomes an unnecessary interference signal in the area 203 depending on the position of the user B, and the mobile phone 204 of the user A and the adaptive array radio base station 201
Will be mixed into the radio signal between the two.

As described above, in the adaptive array radio base station 201 which has received the mixed radio signals from both the users A and B, if no processing is performed, a signal in which the signals from both the users A and B are mixed Is output, and the call of the user A who should originally be talking is hindered.

[Configuration and Operation of Conventional Adaptive Array Antenna] The adaptive array radio base station 201 performs the following processing to remove the signal from the user B from the output signal. FIG. 29 is a schematic block diagram illustrating a configuration of the adaptive array radio base station 201.

First, assuming that the signal from the user A is A (t) and the signal from the user B is B (t), the received signal x1 (1) at the first antenna # 1 of the array antenna 202 shown in FIG. t) is expressed as: x1 (t) = a1 × A (t) + b1 × B (t) + n1
(T) Here, a1 and b1 are coefficients that change in real time as described later, and n1 is a noise component.

Next, the received signal x at the second antenna # 2
2 (t) is expressed as: x2 (t) = a2 × A (t) + b2 × B (t) + n2
(T) Here, a2 and b2 are coefficients that change in real time, and n2 is a noise component.

Next, the received signal x at the third antenna # 3
3 (t) is expressed as: x3 (t) = a3 × A (t) + b3 × B (t) + n3
(T) Here, a3 and b3 are coefficients that change in real time, and n3 is a noise component.

Similarly, the received signal xn (t) at the n-th antenna ♯n is expressed as follows: xn (t) = an × A (t) + bn × B (t) + nn
(T) Here, an and bn are coefficients that change in real time, and nn is a noise component.

The above coefficients a1, a2, a3,..., An
Is the array antenna 2 for the radio signal from the user A.
Are different from each other (for example, the antennas are spaced apart from each other by about 5 times the wavelength of the radio signal, that is, about 1 meter. ) Indicates that there is a difference between the phase and the amplitude at each antenna.

The coefficients b1, b2, b3,...
Similarly, bn indicates that a difference occurs in the phase and amplitude of each of the antennas # 1, # 2, # 3, ..., #n with respect to the radio signal from the user B. As each user moves, these coefficients change in real time.

The signal x1 received by each antenna
(T), x2 (t), x3 (t), ..., xn (t)
The corresponding switches 10-1, 10-2, 10-3, ...,
10-n through the adaptive array radio base station 201
, And is provided to the weight vector control unit 11, and the corresponding multipliers 12-1 and 12-1
, 12-n.

The weights w1, w2, w3,..., Wn for the signals received by the respective antennas are applied from the weight vector controller 11 to the other inputs of these multipliers. These weights are calculated in real time by the weight vector control unit 11 as described later.

Therefore, the received signal x at antenna # 1
1 (t) passes through the multiplier 12-1 and is given by w1 × (a1A
(T) + b1B (t)), and the received signal x2 (t) at the antenna # 2 passes through the multiplier 12-2 and is given by w2 × (a)
2A (t) + b2B (t)), and the received signal x3 (t) at the antenna ♯3 passes through the multiplier 12-3 and becomes w3 ×
(A3A (t) + b3B (t)), and the received signal xn (t) at the antenna #n passes through the multiplier 12-n and becomes wn × (anA (t) + bnB (t)).

These multipliers 12-1, 12-2, 12
-3,..., 12-n are added by the adder 13,
The output is as follows: w1 (a1A (t) + b1B (t) + n1 (t)) + w
2 (a2A (t) + b2B (t) + n2 (t)) + w3
(A3A (t) + b3B (t) + n3 (t)) +... + W
n (anA (t) + bnB (t) + nn (t))

This is expressed in terms of signal A (t) and signal B
.. (W1a1 + w2a2 + w3a3 +... + Wnan) A
(T) + (w1b1 + w2b2 + w3b3 +... + Wnb
n) B (t)

Here, as will be described later, the adaptive array radio base station 201 identifies the users A and B, and extracts the weight w so that only signals from desired users can be extracted.
1, w2, w3,..., Wn are calculated. For example, FIG.
9, the weight vector control unit 11 extracts coefficients a1, a2, a3,..., An, b1, b2, b to extract only the signal A (t) from the user A who should originally be talking.
, Bn are regarded as constants, and weights w1, w2, w3,..., Wn are calculated so that the coefficient of the signal A (t) becomes 1 as a whole and the coefficient of the signal B (t) becomes 0 as a whole. I do.

That is, the weight vector control unit 11
Solves the signal A by solving the following simultaneous linear equation:
The weights w1, w2, w3,..., Wn for which the coefficient of (t) is 1 and the coefficient of signal B (t) is 0 are calculated in real time:

W1a1 + w2a2 + w3a3 +... + Wn
an = 1 w1b1 + w2b2 + w3b3 +... + wnbn = 0

Although the explanation of the solution of this simultaneous linear equation is omitted, it is well known as described in the above-listed documents, and has already been put to practical use in adaptive array radio base stations.

As described above, the weights w1, w2, w3,.
By setting n, the output signal of the adder 13 is as follows: output signal = 1 × A (t) + 0 × B (t) = A (t)

[User Identification and Training Signal] The identification of the users A and B is performed as follows.

FIG. 30 is a schematic diagram showing a frame structure of a radio signal of a portable telephone. A radio signal of a mobile phone is mainly composed of a preamble composed of a signal sequence known to the radio base station and data (such as voice) composed of a signal sequence unknown to the radio base station.

The signal sequence of the preamble includes a signal sequence of information for identifying whether or not the user is a desired user to talk to the radio base station. Weight vector control section 11 (FIG. 29) of adaptive array radio base station 201 compares the training signal corresponding to user A retrieved from memory 14 with the received signal sequence, and includes the signal sequence corresponding to user A. Weight vector control (weight determination) is performed so as to extract a signal that is considered to be present. User A extracted in this way
Is output to the reception processing unit of the adaptive array radio base station 201 as an output signal S _RX (t).

On the other hand, in FIG. 29, the transmission signal S _TX (t) to be transmitted to the mobile phone enters the transmission section 1T constituting the adaptive array radio base station, and the multipliers 15-1 and 15
, 15-3,..., 15-n. The weights w1, w2, w3,..., Wn previously calculated based on the received signal by the weight vector control unit 11 are copied and applied to the other inputs of these multipliers.

The input signals weighted by these multipliers are applied to the corresponding switches 10-1, 10-2, 10
-3,..., 10-n, the corresponding antenna ♯1,
.., #N, and transmitted in the area 203 of FIG.

Here, the same array antenna 20 as used for reception is used.
2 is weighted targeting the user A in the same manner as the received signal, so that the transmitted radio signal is transmitted to the user A as if it has directivity to the user A. It is received by the mobile phone 204. FIG. 31 is a diagram showing an image of transmission and reception of a radio signal between user A and adaptive array wireless base station 201 as described above. The adaptive array radio base station 201 as shown in a virtual region 3a in FIG.
Thus, a state in which a radio signal is radiated with directivity targeting the mobile phone 204 of the user A is imaged.

[0036]

As described above, PDMA
The scheme requires a technique for removing co-channel interference. In this regard, the adaptive array that adaptively directs nulls to the interference wave is an effective means because the interference wave can be effectively suppressed even when the interference wave level is higher than the desired wave level.

However, in the PDMA communication system, there is a problem that when interference signals are close to each other, interference cannot be sufficiently removed. Therefore, multistage interference elimination (Multistage I
nterference Canceler: Hereinafter referred to as MIC. ) Has been attempted to improve the characteristics.

In this MIC, in order to remove an interference signal, it is necessary to accurately restore a signal to be removed. The restored signal (replica signal) is composed of a remodulated signal (a signal obtained by modulating a demodulated signal), a response vector (a propagation path coefficient)
And frequency offset information.

This response vector is obtained by estimating at one point in one slot section. Therefore, if the response vector in the slot fluctuates due to fading or the like, an estimation error occurs in the estimated response vector. If an estimation error occurs in the estimated response vector, an accurate replica signal cannot be generated.

Therefore, a main object of the present invention is to provide a radio receiving system capable of improving the communication quality by reducing the influence of a reception response vector estimation error.

[0041]

According to the first aspect of the present invention, there is provided a wireless receiving system capable of receiving signals from a plurality of users using a plurality of antennas,
Signal processing means for performing predetermined signal processing on the signals received by the plurality of antennas, and a plurality of second signals for extracting signal components respectively corresponding to the plurality of users based on signals output from the signal processing means. And a plurality of reception response vectors from a slot of a propagation path from a specific terminal based on a signal component extracted by the first signal extraction unit with respect to a signal output from the signal processing unit. From the signals output from the estimating means for estimating each parameter information and the signal processing means, and calculating the response vector signal used for the replica signal calculation using the plurality of received response vectors. And a first calculating means for subtracting the replica signal created based on the obtained parameters.

According to the invention described in claim 2, according to claim 1
In the wireless receiving system described in (1), a plurality of first signals for determining whether or not the signal components corresponding to the plurality of users extracted by the first signal extracting means each include a demodulation error.
From the signal output from the signal processing means, the extracted signal component determined to contain no demodulation error by the first error determination means, the parameter obtained by the estimation means And a first calculating means for subtracting the replica signal created based on

According to the invention described in claim 3, according to claim 1
3. The wireless reception system according to claim 1, wherein a plurality of signal components respectively corresponding to the users determined to include the demodulation error by the first error determination unit are extracted based on the signal output from the first calculation unit. A second signal extracting means, and a plurality of second estimating means for estimating parameter information relating to a relationship between a signal output from the first calculating means and a signal component extracted by the second signal extracting means. And a plurality of second error determining means for determining whether or not the signal components extracted by the second signal extracting means each include a demodulation error.

According to the invention described in claim 4, according to claim 3,
Wherein the first and second signal extracting means, which are determined by the first and second error determining means not to include a demodulation error from the signal output from the signal processing means, The image processing apparatus further includes a second calculating unit that subtracts the extracted signal component in consideration of the corresponding parameter information.

According to the invention described in claim 5, according to claim 3,
A signal extracted from the signal output from the first arithmetic unit and extracted by the second signal extraction unit determined to include no demodulation error by the second error determination unit. The image processing apparatus further includes a third calculating unit that subtracts the component by considering the corresponding parameter information.

According to the present invention, in a radio receiving system capable of receiving signals from a plurality of users using a plurality of antennas, a signal processing means for performing predetermined signal processing on signals received by a plurality of antennas A plurality of first signal extracting means for extracting signal components respectively corresponding to a plurality of users based on a signal outputted from the signal processing means; and a first signal extracting means for outputting a signal component from the signal processing means.
The parameter information relating to the relationship between the signal components extracted by the signal extraction means is estimated based on the correlation value between the signal component of the corresponding user and the signal components of other users, and 1
A plurality of first estimating means for estimating a plurality of received response vectors from the slots and estimating a response vector signal used for a replica signal operation using the plurality of received response vectors, and a first signal extracting means; A plurality of first error determination means for determining whether or not the extracted signal components corresponding to the plurality of users each include a demodulation error; and a first error determination means based on a signal output from the signal processing means. A first method of subtracting an extracted signal component determined not to include a demodulation error in consideration of corresponding parameter information.
And arithmetic means.

According to another aspect of the present invention, in a radio receiving system capable of receiving signals from a plurality of users using a plurality of antennas, a signal processing means for performing predetermined signal processing on signals received by a plurality of antennas And a single-stage interference canceller, the single-stage interference canceller includes a plurality of stages of interference cancellers corresponding to a plurality of users, and each stage of the interference canceller includes a plurality of stages based on an input signal. Signal extraction means for extracting and outputting a signal component corresponding to a specific user different for each stage among the users, and a relationship between a signal component extracted by the signal extraction means and a signal input to the signal extraction means. The parameter information is estimated, and a plurality of reception response vectors are estimated from one slot, and the response vectors used for the replica signal operation are calculated using the plurality of reception response vectors. Estimating means for estimating the signal component, a calculating means for removing a signal component corresponding to a specific user from a signal input to the signal extracting means in consideration of parameter information, and a signal component corresponding to the specific user being demodulated. It is determined whether or not an error is included, and if it is determined that the error is included, an error determination unit that disables removal of the signal component corresponding to the specific user by the calculation unit is included. A signal output from the signal processing means is input to the input of the arithmetic means, and the output of the arithmetic means of the interference elimination section in the preceding stage of the two adjacent interference elimination sections is used as the signal extraction means and the arithmetic means of the interference elimination section in the subsequent stage. , And a plurality of stages of interference cancellers can be connected.

[0048]

FIG. 1 shows a PD to which the present invention is applied.
FIG. 3 is a schematic block diagram illustrating a configuration of a radio apparatus (radio base station) 1000 of the MA base station.

In the configuration shown in FIG. 1, the user PS
1 and PS2, four antennas # 1 to
# 4 is provided. However, the number of antennas may be more generally N (N: natural number).

In transmission / reception system 1000 shown in FIG. 1, signals from antennas # 1 to # 4 are received, and a signal is sent to receiving section SR1 and user PS1 for separating a signal from a corresponding user, for example, user PS1. A transmission unit ST1 for transmitting a signal is provided. Antenna ♯
The connections between 1 to $ 4 and the receiving unit SR1 and the transmitting unit ST1 are selectively switched by switches 10-1 to 10-4.

That is, the received signals RX ₁ (t), RX ₂ (t), RX ₃ (t),
RX ₄ (t) corresponds to the corresponding switch 10-1, 10-
Enter the receiving unit SR1 via 2,10-3,10-4,
It is provided to the reception weight vector calculator 20 and the reception response vector calculator 22, and the corresponding multiplier 12-
1, 12-2, 12-3, and 12-4.

To the other inputs of these multipliers, weight coefficients wrx11, wrx21, wr for the signals received by the respective antennas are received from the reception weight vector calculator 20.
x31 and wrx41 are applied. These weighting factors are calculated by the reception weight vector calculator 20 as in the conventional example.
Is calculated in real time.

Upon receiving the reception response vector calculated by the reception response vector calculator 22, the transmitting unit ST1 estimates a propagation path at the time of transmission, that is,
A transmission response vector estimator 3 for obtaining a transmission response vector by estimating a virtual reception response vector at the time of transmission
2, a memory 34 for transmitting and receiving data between the transmission response vector estimator 32 and storing the data, and a transmission weight vector calculator for calculating a transmission weight vector based on the estimation result of the transmission response vector estimator 32 30
The weight coefficient wtx1 from the transmission weight vector calculator 30 is input to the other input while receiving the transmission signal at one input.
1. Multipliers 15-1, 15-2, 15-3, and 15-4 to which 1, wtx21, wtx31, and wtx41 are applied. Outputs from multipliers 15-1, 15-2, 15-3, and 15-4 are provided to antennas # 1 to # 4 via switches 10-1 to 10-4.

Although not shown in FIG. 1, a configuration similar to that of receiving section SR1 and transmitting section ST1 is provided for each user.

[Operation Principle of Adaptive Array] The operation of the receiving section SR1 will be briefly described as follows.

The received signal RX received by the antenna
₁ (t), RX ₂ (t), RX ₃ (t), RX ₄ (t)
It is represented by the following equation.

[0057]

(Equation 1)

Here, the signal RXj (t) is the j-th signal (j
= 1, 2, 3, 4), and the signal Srxi (t) indicates the signal transmitted by the i-th (i = 1, 2) user.

Further, the coefficient hji indicates the complex coefficient of the signal from the i-th user received by the j-th antenna, and nj (t) indicates the noise (noise) included in the j-th received signal. Is shown.

When the above equations (1) to (4) are expressed in a vector format, they are as follows.

[0061]

(Equation 2)

In the equations (6) to (8), [...] ^T
Indicates transposition of [...]. Here, X (t) is an input signal vector, _Hi is a reception response vector of the i-th user,
N (t) indicates a noise vector.

As shown in FIG. 1, the adaptive array antenna multiplies the input signals from the respective antennas by weighting factors wrx1i to wrx4i and outputs a signal as a received signal SRX (t).

Now, with the above preparation, the operation of the adaptive array in the case of extracting the signal Srx1 (t) transmitted by the first user, for example, is as follows.

Output signal y1 (t) of adaptive array
Is the input signal vector X (t) and the weight vector W1
Can be expressed by the following equation.

[0066]

(Equation 3)

That is, the weight vector W1 is obtained by multiplying the j-th input signal RXj (t) by the weight coefficient w
This is a vector having rxj 1 (j = 1, 2, 3, 4) as an element.

Here, y1 expressed as in equation (9)
Substituting the input signal vector X (t) expressed by equation (5) into (t) yields the following.

[0069]

(Equation 4)

Here, when the adaptive array operates ideally, the weight vector W1 is calculated by a known method.
Are sequentially controlled by the weight vector control unit 11 so as to satisfy the following simultaneous equations.

[0071]

(Equation 5)

When the weight vector W1 is completely controlled so as to satisfy the equations (12) and (13), the output signal y1 (t) from the adaptive array 100 is eventually expressed by the following equation.

[0073]

(Equation 6)

That is, the output signal y1 (t) includes the signal Sr transmitted by the first user of the two users.
x1 (t) is obtained.

[Overview of Operation of Wireless Device 1000] FIG.
8 is a flowchart for explaining an outline of the operation of the wireless device 1000.

Focusing on the fact that the weight vector (weight coefficient vector) of the adaptive array can be uniquely represented by the reception response vector of each antenna element, radio apparatus 1000 indirectly estimates the time variation of the reception response vector. To estimate the weight.

First, the receiver SR1 estimates the propagation path of the received signal based on the received signal (step S1).
100). The estimation of the propagation path corresponds to obtaining the impulse response of the signal sent from the user in the equations (1) to (4).

In other words, in equations (1) to (4), for example, if the reception response vector H ₁ can be estimated,
The transmission path at the time of receiving the signal from the user PS1 can be estimated.

Subsequently, the transmission response vector estimator 32
Perform the prediction of the propagation path at the time of transmission, that is, the prediction of the reception coefficient vector at the time of transmission from the reception coefficient vector at the time of reception (step S102). The predicted reception coefficient vector corresponds to a transmission coefficient vector at the time of transmission.

Further, the transmission weight vector calculator 30
Calculates the transmission weight vector based on the predicted transmission response vector, and calculates the multipliers 15-1 to 15-4.
(Step S104).

[Operation of Reception Response Vector Calculator 22] Next, the operation of reception response vector calculator 22 in the first embodiment shown in FIG. 1 will be described.

First, when the number of antenna elements is four and the number of users simultaneously communicating is two, signals output from the receiving circuit via each antenna are expressed by the above-described equations (1) to (4).
Is represented by

At this time, if the expressions representing the received signals of the antennas represented by the expressions (1) to (4) are represented by vectors again, the following expressions (5) to (8) are obtained.

[0084]

(Equation 7)

Here, if the adaptive array is operating well, the signals from each user are separated and extracted, so that the signals Srxi (t) (i = 1, 2) are all known values. Become.

At this time, using the fact that the signal Srxi (t) is a known signal, the reception response vector H ₁ = [h
11, h21, h31, h41] and _{H 2 = [h12, h22,} h
32, h42] can be derived as described below.

That is, the received signal and the known user signal, for example, the signal Srx1 (t) from the first user
Is multiplied by the received signal X (t), and the ensemble average (time average) is calculated as follows.

[0088]

(Equation 8)

In equation (16), E [...] indicates a time average, and S * (t) indicates a conjugate complex of S (t).
If the averaging time is long enough, the average value is as follows.

[0090]

(Equation 9)

Here, the value of equation (18) becomes 0 because
This is because the signal Srx1 (t) and the signal Srx2 (t) have no correlation with each other. The value of the equation (19) becomes 0 because there is no correlation between the signal Srx1 (t) and the noise signal N (t).

Therefore, the ensemble average of equation (16) results in the reception response vector H
Equals ₁ .

[0093]

(Equation 10)

[0094] The procedure described above, it is possible to estimate the reception response vector H ₁ of the signal transmitted from the first user PS1.

[0095] Similarly, by performing the ensemble average operation input signal vector X (t) and the signal Srx2 (t), is possible to estimate the reception response vector of H ₂ signal transmitted from second user PS2 It is possible.

The above-described ensemble averaging is performed, for example, on a predetermined number of leading data symbol strings and a predetermined number of trailing data symbol strings in one time slot at the time of reception.

However, if one estimation of this response vector is obtained and calculated in one slot section, an accurate restored signal cannot be generated if the response vector in the slot fluctuates due to fading or the like. Come. Therefore, in the present invention, as described later, the response vector in one slot section is estimated at a plurality of points, and the response vector of each sample is calculated from the plurality of response vectors.

Since the present invention focuses on the processing at the time of reception in the radio reception system, the description of the estimation of the transmission response vector is omitted here.

Next, FIG. 4 is a conceptual diagram for explaining a principle of estimating a response vector which is a premise of estimating a response vector according to the present invention. The “ideal state” is a case where there is no fading or the like and the response vector does not fluctuate.

In step S100 of FIG. 2, the reception response vector calculator 22 of FIG. 1 estimates and obtains the reception response vector at the calculated leading edge in the same slot of the uplink. Then, the reception response vector is estimated by performing extrapolation based on the reception response vector.

Here, the “ideal state” in FIG. 3 is based on the assumption that there is no estimation error in the reception response vector. That is, one response vector is estimated in slot 1 and calculated as a response vector of each symbol in one slot. If there is no estimation error, a correct replica signal can be created.

However, as shown in FIG. 3B, when the response vector fluctuates due to fading or the like, an error occurs between the actual response vector and the response vector estimated based on the ideal state. As described above, when the reception response vector is shifted due to an estimation error due to noise or sampling error, an accurate response vector cannot be obtained by similarly performing a linear extrapolation based on the reception response vector. become.

As described above, the response vector is estimated by the ensemble average of the correlation between the remodulated signal of the error-free user and the received signal (antenna input signal). If an error is included in the response vector, erroneous information is removed at the time of interference removal.As a result, necessary information is removed or noise is inserted. Required.

Therefore, in the present invention, the estimation of the received response vector is calculated from a plurality of response vectors. FIG. 4 is a conceptual diagram illustrating the estimation principle of response vector estimation according to the present invention.

In the embodiment shown in FIG. 4, there are two responses at the leading edge (the section where all the reference (UW) signals overlap) and the center (the section where all the user signals except the lamp guard overlap). A vector is estimated, and the information is used to extrapolate and calculate a response vector for each sample in one slot. In this way, by estimating the response vector from a plurality of points, it is possible to cope with a case where the response vector fluctuates due to fading or the like.

The following is a description of the method of estimating the response vector estimated at the leading edge and the center of the received signal X multiplexed by four.
The case where the response vector h1 of the user 1 is estimated from the following will be described as an example.

It is assumed that the received signal X is expressed as in equation (31).

X = (h1 * D1) + (h2 * D2) + (h3 * D3) + (h4 * D4) + n (31) where Di and hi (i = 1, 2, 3, 4) Is the remodulated signal and response vector at user i, and n is noise.

Here, as in equation (32), equation (31)
Is multiplied by the re-modulated signal D1 of the user 1, and an ensemble of signal correlation is averaged.

E [X * D1 ^* ] = h1 * E [D1 * D1 ^* ] + h2 * E [D2 * D1 ^* ] + h3 * E [D3 * D1 ^* ] + h4 * E [D4 * D1 ^* ] + E [n * D1 ^* ] ... (32)

Here, it is assumed that D ^* is the complex conjugate of each element of the vector D and is transposed. Also, E [D1
* D1 ^* ] = 1 and E [n * D1 ^* ] = 0. In terms of E [Si * S1 ^* ] except for i = 1, if the Si user is not error-free (known signal), E [Si * S1 ^* ]
= 0. However, when an error user signal is also used, E [Si * S1 ^* ] is actually calculated.

In the above equation (32), if the term to be correlated is only the autocorrelation, equation (32) is given by E [X * D1 ^* ]
= H1, which is easily obtained, but when cross-correlation is taken, equation (32) relating to the user is similarly set, and each response vector is calculated by simultaneous equations (matrix operation).

When signal correlation between users is to be obtained, it is necessary to match the time of the information of all users on a sample basis with reference to the symbol timing of the user i for which the signal correlation is to be obtained. In the case of the above equation (32), the user 1
The data is extracted for each symbol from the symbol synchronization position (sample position) and calculated.

The response vector of the lamp guard section is
Since it is a rising / falling section of power, it cannot be estimated by the above method.

Using the technique described above, two response vectors at the leading edge and the center are estimated. The value of the response vector estimated by the ensemble average of the signal correlation between the leading edge and the central portion is regarded as the central value of each ensemble average section.

The response vector calculator 22 calculates the response vector of each sample in the slot using the response vector values of the two points of the leading edge and the center obtained as described above. At the time of this calculation, the sample points between the two points are interpolated, and those outside the sample point are extrapolated. The received signal processing using the above estimation method is performed according to the flowchart shown in FIG.

This operation will be described with reference to FIG. First, the number of users who need array processing is determined (step S101). Next, the synchronous position of the received signal is detected (step S102). A desired signal is extracted from the received signal (step S103), and demodulation processing for converting the phase information of the desired signal into bit information is performed (step S10).
4).

Then, it is determined whether or not the demodulated signal is correct, that is, whether or not there is an error is recorded (step S10).
5). Thereafter, it is determined whether or not the processing for the required number of users has performed the array processing. If the processing has not been performed, the process returns to step S101 and the above-described operation is repeated. When the processing for the number of users requiring the array processing is performed, it is determined whether or not it can transition to the next stage based on the demodulation error determination result (step S107).

It is determined whether or not to go to the next stage (step S108). If not to go to the next stage, the operation is terminated. To go to the next stage, the demodulated bit information is converted again to phase information (step S108). Step S109).

Subsequently, the phase amplitude information of the user to be removed (the user who has undergone remodulation processing) is estimated, and the response vector is estimated (step S110). This response vector estimation is performed by estimating two response vectors at a leading edge (a section where all reference (UW) signals overlap) and a central part (a section where all user signals except for the lamp guard overlap). Interpolation and extrapolation are performed using the information to calculate a response vector for each sample in one slot.

Subsequently, a replica signal of the user signal to be removed from the re-modulated signal and the response vector is generated (step S111). Then, the replica signal is removed from the received signal (step S112), the process returns to step S101, and the above-described operation is repeated.

As described above, the response vector at a plurality of points in one slot is estimated, the response vector value is used, and the response vector of each sample in the slot is used. The generation accuracy of the replica signal can be improved.

Here, the frequency offset is a difference between the frequencies slightly shifted because the accuracy of the frequency on the transmitter side is different from the accuracy of the frequency on the receiver side. When the unit of the estimated frequency offset Theta is one symbol, the difference of the frequency offset increases as the symbol advances. As described above, when the frequency offset exists and the estimated value includes an error, the influence of the frequency offset can be reduced by calculating the response vector by the above-described method. When the response vector values at the two points, the leading edge and the center, are used, the effects of the frequency offset cancel each other out, and the improvement of the replica signal generation accuracy can be expected.

The effect of the response vector at the time of estimation will be described. If there is a frequency offset at the time of estimating the response vector, it is necessary to perform inverse compensation of the frequency offset (here, the frequency offset has already been estimated) on the remodulated signal and generate a reference signal. There is. That is, since the received signal X includes a frequency offset, reverse compensation is required.

At this time, if there is an error in the frequency offset, the error will be added to the reference signal. For example, if the error is Δtheta, an error of i × Δtheta will occur in the inverse compensation at the position of the symbol i.

When the above-described estimation of the response vector of the present invention is used, an operation for filling an error is performed. Hereinafter, the operation will be described.

In the “section where all user signals except for the lamp guard overlap”, inverse compensation of the frequency offset is performed on all the symbols and the ensemble average is taken, so that the frequency offset error with respect to the reference signal is the center of the section. The error (m × Δtheta) at the symbol position is included.

Here, assuming that the true frequency offset of user 1 is theta and that of users 2 to 4 include a received signal X having no frequency offset for the sake of simplicity, equation (31) becomes Equation (33) is obtained.

X = (h1 * D1 * theta) + (h2 * D2) + (h3 * D3) + (h4 * D4) + n (33)

However, assuming that the estimated frequency offset of the user 1 includes a negative error Δtheta, the equation (32) becomes as shown in the equation (34).

E [X * S1 ^* ] = h1 * E [S1 * S1 ^* ] + h2 * E [D2 * S1 ^* ] + h3 * E [D3 * S1 ^* ] + h4 * E [D4 * S1 ^* ] + E [ n * S1 ^* ] (34) Here, S1 is a reference signal obtained by multiplying the remodulated signal of the user 1 by a frequency offset (theta−Δtheta).

Here, in order to simplify the explanation, if the cross-correlation between the user 1 and the users 2 to 4 is assumed to be 0, the equation (3)
4) is as follows.

E [X * (theta−Δtheta) * D1 ^* ] = h
1

As described above, the response vector to be estimated
Theta error is added, and Δt for the true response vector h1
heta will be added. That is, since there is a negative error in the frequency offset, the reference signal S1 generates an error in the negative direction, and a difference is generated between the reference signal S1 and the true response vector. The phase will advance in the direction. Therefore, when the response vector values at the two points of the leading edge and the center are used, the influence of the frequency offset is more canceled out, and the improvement of the replica signal generation accuracy can be expected.

FIG. 6 is a block diagram showing a receiving system of a PDMA base station proposed as a multi-stage interference canceller to which the present invention is applied. The receiving system of the present invention provides a signal S ₁ from m (m is an integer of 2 or more) users 1,..., K,.
, S _k (t),..., S _m (t) are separated from each other and extracted in parallel.

In FIG. 6, as in the conventional example, the PDMA
The base station receiving system has four antennas 3 to 6
And a frequency conversion circuit 7 and an A / D converter 8.
ing. Input signal vector output from A / D converter 8
Le X₁(T) shows the first stage arithmetic unit 101 and the first stage
Eye Adaptive Array AA₁₁, ..., AA_k1, ..., AA
_m1And the first-stage parameter estimator PE₁₁, ..., P
E_k1, ..., PE_m1And given to. Adaptive array
Details will be described later.

The adaptive arrays AA ₁₁ ,..., AA _k1 ,
, AA _m1 are user signals Y ₁₁ (t),..., Y _k1 which are complex signals that include the signal components of the corresponding user most strongly (and also include interference signal components from other users).
_{(T), ..., Y m1} (t) is outputted, together with given to the arithmetic unit 101 of the first stage, detector DE ₁₁ respectively corresponding, ..., DE _k1, ..., are detected by DE _m1 .

The parameter estimators PE ₁₁ ,..., PE _k1 ,
, PE _m1 are input signal vectors X ₁ (t), respectively.
If, detectors _{DE 11, ..., DE k1,} ..., based on the corresponding detection output DE _m1, the corresponding reception response vector H ₁₁ users, ..., H _k1, ..., to estimate H _m1, the This is given to the first-stage arithmetic unit 101. More specifically, each parameter estimator determines how much the corresponding user signal component is included in the input signal vector, how much the corresponding user signal component is phase-rotated with respect to the input signal vector, Estimate.

The above-described parameter estimator uses the values of the two response vectors estimated by the ensemble average of the signal correlations of the leading edge and the center, for example, to calculate the received response vector for each sample of the slot. It is calculated as a response vector.

The first stage of the arithmetic unit 101 is connected to each user i.
(I = 1, 2,..., M), the input signal vector X ₁
By subtracting the signal components of all the users except the user i from (t), the interference signal component is removed, and the further input signal vector X of the user i is removed.
Calculate and output _i2 (t). The operation of the arithmetic unit 101 will be described later in detail with reference to FIG.

The first-stage arithmetic unit 101 inputs the input signal vector X ₁₂ (t),.
_k2 (t), ..., and outputs the X _m2 (t), the adaptive array AA ₁₂ of the corresponding second _{stage, ..., AA k2, ...,} AA m2
Give to.

The second-stage adaptive array AA ₁₂ ,
..., AA _k2, ..., user signal Y ₁₂ output from AA _{m @ 2}
, Y _k2 (t),..., Y _m2 (t) are _{supplied to} the second-stage arithmetic circuit 102 and the corresponding detectors DE ₁₂ ,..., DE _{k2,. Detected} at _m2 .

The parameter estimators PE ₁₂ ,..., PE _k2 ,
.., PE _m2 are input signal vectors X ₁ (t), respectively.
If, detector _{DE 12, ..., DE k2,} ..., based on the corresponding detection output DE _{m @ 2,} the reception response vector H ₁₂ of the corresponding user, ..., H _k2, ..., to estimate H _{m @ 2,} the This is given to the second-stage arithmetic unit 102. The arithmetic unit 102 further inputs the input signal vectors X ₁₃ (t),..., X _k3 (t) _,.
(T) and outputs a corresponding (and not shown) the third stage adaptive arrays _{AA 13, ..., AA k3,} ..., gives the AA _m3.

As described above, by providing a plurality of stages (from the first stage to the L-th stage) of the interference canceller composed of the adaptive array, the parameter estimator and the arithmetic unit in series,
The ratio of other user signal components included in the user signal output from each stage is gradually reduced, so that interference can be further eliminated. As a result, the communication characteristics are further improved.

FIG. 7 is a specific block diagram of the arithmetic unit 101 as an example of the multi-stage arithmetic unit shown in FIG. 7, the arithmetic unit 101 includes multipliers MP ₁ ,
, MP _k−1 , MP _{k + 1} ,..., MP _m and an adder AD _k . Although not shown for the sake of simplicity, the multiplier MP _k and the adders AD ₁ ,..., AD _k−1 , AD _{k + 1} ,
.., AD _m are built in the arithmetic unit 101.

The multipliers MP ₁ ,..., MP _k−1 , MP _{k + 1} ,
, MP _m are adaptive arrays AA ₁₁ ,
_{..., AA k-1, AA} k + 1, ..., user signal Y from AA _m
11 (t), ..., Y _{(k-1) 1} (t), Y _{(k + 1) 1} (t), ...,
Y _m1 (t) and parameter estimators PE ₁₁ ,.
_{(k-1) 1, PE} (k + 1) 1, ..., reception response vector H ₁₁ from _{PE m1, ..., H (k} -1) 1, H (k + 1) 1, ..., a H _m1 Is given. As described above, the reception response vector is calculated as a response vector of each sample of the slot using the values of the response vectors of the two points estimated by the ensemble average of the signal correlations of the leading edge and the center. It is.

The multipliers MP ₁ ,..., MP _k−1 , MP _{k + 1} ,
, MP _m are given to the negative input of adder AD _k ,
Input signal vector X ₁ (t) is applied to the positive input of adder AD _k. Thereby, the input signal vector X ₁ (t)
Is subtracted from the signal components corresponding to the users other than the user k, and the signal component X _k2 (t) corresponding to the user k is added to the adder A
D _k will be output. As described above, it is assumed that the adaptive array, the parameter estimator, and the arithmetic device as a whole constitute a single-stage interference canceller.

As a result, a considerable interference signal component is removed. Then, in this way, the arithmetic unit 10
1, a new input vector signal X _k2 (t) from which the interference signal component has been considerably removed is given to the second and subsequent interference cancellers, so that the finally output user signal S
The ratio of interference signal components from other users included in _k (t) can be sufficiently reduced, and good communication characteristics can be realized.

Incidentally, each of the adders (not shown) other than the adder AD _k is similarly provided in parallel with the multipliers MP ₁ ,.
Outputs from P _k ,..., MP _m other than the multiplier corresponding to the adder and an input signal vector X ₁ (t) are provided. Each of these adders is shown in FIG.
Are output and given to the second and subsequent interference cancellers.

Next, a more specific operation of the apparatus shown in FIGS. 6 and 7 will be described. The number of antenna elements is n
Assuming that the number of users who simultaneously talk is m, the input signal vector X ₁ (t) output from the A / D converter 8 is expressed by the following equation.

X₁(T) = [x₁(T), x_Two(T), ... x_n(T)]^T ... (41) x_j(T) = h_j1S₁(T) + h_j2S_Two(T) + ... + h_jiS_i(T) + ... + h_jmS _m (T) + n_j(T), (j = 1, 2,..., N) (42) Expressions (41) and (42) above are expressed in vectors.
The following equation (43) is obtained.

X ₁ (t) = H ₁ S ₁ (t) + H ₂ S ₂ (t) +... + _Hi S _i (t) +... + H _m S _m (t) + N (t). _i = [h _1i , h _2i ,..., h _ni ] ^T , (i = 1, 2,..., m) (44) N (t) = [n ₁ (t), n ₂ (t),. , N _n (t)] ^T (45)

Next, the operation of outputting a new input signal vector X _k2 (t) from the arithmetic unit 101 in FIG. 7 will be described in further detail.

The parameter estimators PE ₁₁ ,..., PE _k1 ,
_{..., H i (i = 1,2} , ..., m) in PE _m1 is assumed to be estimated. The first-stage adaptive array AA ₁₁ ,
, AA _k1 ,..., AA _m1 operate relatively well, it can be considered that Y _i1 (t) ≒ S _i (t).

At this stage, all user signals and reception response vectors of all user signals have been obtained. Here, the input signal vector X _k2 (t) used for detecting the signal of the user k in the second stage can be obtained by Expression (46).

X _k2 (t) = X ₁ (t) −H ₁ S ₁ (t) −... −H _k−1 S _k−1 (t) −H _{k + 1} S _{k + 1} (t) −. −H _m S _m (t) (46) By substituting equation (43) into equation (46), (4)
7) is obtained.

[0157] _{X k2 (t) = H k} S k (t) + N (t) ... (47) when compared to X ₁ and (t) X _k2 a (t), towards the X _k2 (t) is S _k ( The interference components S _i (t) other than t) (i = 1, 2,...)
m, where i ≠ k) is reduced, and the second-stage adaptive array becomes easier to operate.

As shown in FIG. 6, in a multi-stage interference canceller configured by connecting a plurality of interference cancellers, a received signal is separated for each user by an adaptive array, and signals of users other than the user are used as interference waves. The result obtained by removing from the received signal is given to the next-stage interference canceller as an input signal of the user. As a result, in the interference canceller at the next stage, a user signal with good communication characteristics can be obtained because the interference wave of the input user signal is small. Then, the interference wave removal is further advanced by repeating such interference wave removal in a plurality of stages, and the CIR (Car
The carrier to interference ratio is further improved and a desired user signal can be more easily extracted.

However, if the multi-stage interference canceller as described above is used, the removal of the interference wave proceeds, but the following problem occurs.

(1) In the above-described example of the multi-stage interference canceller, the user signal extracted by each adaptive array can be extracted without judging the presence or absence of a demodulation error.
It is configured to remove as an interference wave component from the received signal. Therefore, if there is a demodulation error in the user signal extracted by the adaptive array and a signal having some deformed waveform, for example, an impulse-like waveform, a signal component containing such an error is subtracted from the received signal. As a result, the output of each arithmetic unit (input signal to the next stage interference canceller) obtained has an effect such that impulse noise is included due to the influence of the demodulation error.

(2) As described with reference to FIG.
Each signal removed from the received signal X ₁ (t) by the adder AD _k is a product of a reception response vector calculated by each parameter estimator and a user signal extracted by each adaptive array (hereinafter, a replica signal). ).

Here, the reception response vector calculated by each parameter estimator does not consider the correlation value between the user signal of the user and the user signals of other users at all. Is set to 0.

In reality, there is a correlation between a plurality of user signals, and therefore, the above calculation method is not suitable for an actual propagation environment. Therefore, when the interference wave is removed using the reception response vector obtained by the calculation method in which the correlation value with the user signal of another user is set to 0, an error is included in the output of each arithmetic device. there is a possibility.

The following embodiment is to solve the above problems (1) and (2).

[Embodiment 1] FIG. 8 is a block diagram showing a receiving system of a PDMA base station according to Embodiment 1 of the present invention.

In FIG. 8, an arithmetic unit 101 'and a first gate unit GA, an interference elimination unit IC and a second gate unit GB provided for each of a plurality of users are provided as a first-stage interference canceller. It has a basic configuration.

Although omitted for the sake of simplicity of illustration, the first gate units GA and GA are arranged in the same manner as the first-stage interference canceller for each of a plurality of users in the subsequent stage of the arithmetic unit 102 '. It is assumed that an interference removing unit IC and a second gate unit GB are provided, and a second-stage interference canceller is configured by the arithmetic unit 102 'and these components GA, IC, and GB (not shown). .

Although not shown in the figure, the second stage interference canceller is also configured in the same manner as the first stage interference canceller in the subsequent stage (the arithmetic unit, the first and second interference cancellers).
It is assumed that a plurality of stages of interference cancellers (consisting of a gate unit and an interference canceller) continue.

Therefore, the receiving system of FIG. 8 is constituted as a whole by a multi-stage interference canceller, and the second gate section GB (shown in FIG. 8) provided for each of a plurality of users of the final-stage interference canceller. Is the final output of the receiving system.

First, as in the receiving system of FIG.
The input signal vector X ₁ (t) is output from the D converter 8 and supplied to the arithmetic unit 101 ′ of the first-stage interference canceller, and is provided for each of a plurality of users before the first-stage interference canceller. , IC _k1 ,..., IC _m1 are provided in common to a plurality of interference removal units IC _{11 ,.}

In the receiving system shown in FIG. 8, all the interference removing units IC have the same configuration. As an example, the configuration of the interference removing unit _ICk1 is shown in FIG.

In FIG. 9, the complex signal of the user k extracted by the adaptive array AA _k1 from the input signal vector X ₁ (t) input to the interference canceller IC _k1 is converted to a demodulator D
It is converted into a bit information signal by M _k1 . This bit information signal is _supplied to the error determiner ED _k1 and also to the re-modulator RM _k1 .

The error determiner ED _k1 is based on the bit information signal from the demodulator DM _k1 and uses the adaptive array AA
The presence / absence of a demodulation error of the extracted signal from _k1 is determined. If it is determined that there is a demodulation error, an L-level error determination signal E _k1 is generated and supplied to the arithmetic unit 101 ′ of the first-stage interference canceller.

The re-modulator RM _k1 again converts the bit information signal from the demodulator DM _k1 into a complex
_k1 (t), which is provided to the first stage interference canceller arithmetic unit 101 ', and the parameter estimator PE _k1
Give to.

The parameter estimator PE _k1 calculates the reception response vector H _k1 of the corresponding user based on the input signal vector X ₁ (t) and the user signal Y _k1 (t),
This is given to the arithmetic unit 101 'of the first-stage interference canceller. Also in this embodiment, as described above, the reception response vector has two parts, a leading edge (a section where all reference (UW) signals overlap) and a central part (a section where all user signals except for the lamp guard overlap). Estimate the response vector at the location,
The information is used to extrapolate and calculate the response vector for each sample in one slot. The same applies to the following embodiments.

Since the arrangement of the adaptive array, demodulator, error determiner, remodulator and parameter estimator as shown in FIG. 9 is common to all the interference canceller ICs in FIG. 8, further description will be repeated. Absent.

FIG. 10 is a block diagram showing a specific configuration of the arithmetic unit 101 'of the first-stage interference canceller as an example of the multi-stage interference canceller constituting the receiving system of FIG. In FIG. 10, the arithmetic unit 101 '
Multipliers MP ₁ ,..., MP _k−1 , MP _k , MP _{k + 1} ,.
_m , and AND gates AND ₁ ,..., AND _k−1 , AND _k ,
AND _k + 1, ..., and the AND _m, and an adder AD.

Multipliers MP ₁ ,..., MP _k−1 , MP _k , MP
_{k + 1} ,..., MP _m are respectively the interference canceller IC
_{1 1} , ..., IC _{(k-1) 1} , IC _k1 , IC _{(k + 1) 1} , ..., IC
User signals Y ₁₁ (t),..., Y _{(k-1) 1} (t) from _m1
Y _k1 (t), Y _{(k + 1) 1} (t),..., Y _m1 (t) and received signal response vectors H ₁₁ ,..., H _{(k−1) 1} , H _k1 , H _{(k + 1) 1} ,
.., H _m1 .

Multiplier MP₁,…, MP_k-1, MP_k, MP
_{k + 1},…, MP_mOutput is the corresponding AND gate
AND₁, ..., AND_k-1, AND_k, AND_{k + 1}, ..., A
ND _mOf these AND gates
The other input is an interference canceller IC in the preceding stage.₁₁, ..., IC
_{(k-1) 1}, IC_k1, IC_{(k + 1) 1}, ..., IC_m1Response from
Error determination signal E₁₁, ..., E_{(k-1) 1}, E_k1, E_{(k + 1) 1},
…, E_m1Is entered.

AND gates AND ₁ ,..., AND _k−1 , A
The outputs of ND _k , AND _{k + 1} ,..., AND _m are given to the negative input of adder AD, and the input signal vector X ₁ (t) from A / D converter 8 is the positive input of adder AD. Given to.

The output of the adder AD is the input signal vector X ₂
Is output from the arithmetic unit 101 'as (t), as shown in FIG. 8, first gate GA ₁₂ corresponding to a plurality of users, ..., GA _k2, ..., commonly applied to GA _{m @ 2.}

Although not shown in the block diagram of the arithmetic unit 101 'in FIG.
_{11, ..., IC k1, ...} , reception response vector H ₁₁ output from the _{IC m1, ..., H k1,} ..., H m1, the error determination signal _{E 11, ..., E k1,} ..., E m1, and the user signal Y
₁₁ (t),..., Y _k1 (t),..., Y _m1 (t) pass through the arithmetic unit 101 ′ as it is, and correspond to the first gate unit GA of the first-stage interference canceller for each user. ₁₂ ,…,
GA _k2 ,..., GA _m2 .

Here, referring to FIG. 10, interference canceller I corresponding to a user signal determined to have a demodulation error in the preceding stage interference canceller, for example, Y ₁₁ (t), as described above.
Corresponding AND gate AN of the error determination signal E ₁₁ from error determining unit ED ₁₁ of L level C ₁₁ is the arithmetic unit 101 '
It is applied to the other input of the D _1. As a result, the AND gate is closed, is output from the multiplier MP ₁ corresponding product of the reception response vector H _{1 1} and the user signal Y ₁₁ (t), that is, the input to the adder AD of the replica signal Will be blocked.

As a result, the interference wave component (replica signal) corresponding to the user signal including the demodulation error is excluded from the interference wave component (replica signal) of each user to be subtracted from the input signal vector X ₁ (t). Is done. Therefore, for example, the input signal vector X ₂ (t) output from the arithmetic unit 101 ′ of the first-stage interference canceller does not include, for example, impulse noise.

In the first-stage interference canceller, the selection control input of the first gate section GA corresponding to each user, for example, the gate section GA ₁₂ corresponding to the user 1, is supplied from the interference canceller IC ₁₁ of the preceding stage. error signal E ₁₁ that has passed through the arithmetic unit 101 'is provided.

If the interference removal unit IC ₁₁ at the preceding stage has determined that there is an error, the first gate unit G
A ₁₂ in response to the error determination signal E _11, the arithmetic unit 10
1 ′, the noise-free high-precision input signal vector X ₂ (t) newly selected is selected and the interference canceller IC ₁₂ is selected.
Give to.

This interference removing unit IC ₁₂ is the same as the IC shown in FIG.
_As described in connection with _k1 , this input signal vector X
Based on ₂ (t), a reception response vector H _12, the error determination signal E _12, the newly calculated and the user signal Y ₁₂ (t), gives to the second gate section GB _12.

On the other hand, when the interference removal unit IC ₁₁ at the preceding stage has determined that there is no error, the first gate unit GA
_12, in accordance with the error determination signal E _11, the arithmetic unit 101 '
Was passed through the receiving response vectors H _11, giving to the error determination signal E _11, the second gate portion GB ₁₂ selects a user signal Y ₁₁ (t).

Second gate portion GB₁₂To select control input
Is the first gate unit GA₁₂Error determination signal E₁₁
Is given. Second gate part GB₁₂Is the interference removal
Back IC₁₁If it is determined that there is an error in
Error determination signal E₁₁According to the interference removal unit IC₁₂New
Response vector H calculated in₁₂, Error determination signal E
₁₂And user signal Y₁₂(T) is selected and output, and the second
To the arithmetic unit 102 'which constitutes the first-stage interference canceller.
I can.

[0190] On the other hand, the second gate unit GB _12, when the determination of no error has been made in the preceding stage interference removing unit IC ₁₁ in accordance with the error determination signal E _11, the first gate portion G
The reception response vector H ₁₁ , the error determination signal E _11, and the user signal Y ₁₁ (t) sent from the A ₁₂ are selected and output as they are, and the reception response vector H ₁₂ , the error determination signal E 11
₁₂ and the user signal Y ₁₂ (t) are given to the arithmetic unit 102 ′ constituting the second-stage interference canceller.

Exactly the same operations are performed in the gate units GA and GB and the interference removal unit IC corresponding to users other than the user 1, and the description thereof will be omitted.

To summarize the above operation, among the interference canceller ICs in the preceding stage that received the input signal vector X ₁ (t), for the user determined to have no error, the reception calculated by the interference canceller IC was used. The response vector H, the error determination signal E, and the user signal Y (t) are left as they are, and the arithmetic unit 101 'of the first-stage interference canceller, the first gate unit GA, and the second gate unit GB And is provided to the second-stage interference canceller. That is, the user once determined that there is no error by the interference canceling unit IC is no longer given to the interference canceling unit IC of the subsequent interference canceller, and the reception response vector H and the error judgment signal E
No new user signal Y (t) is calculated.

On the other hand, among the interference canceller ICs at the preceding stage that have received the input signal vector X ₁ (t), for the user determined to have an error, noise is reduced by the arithmetic unit 101 ′ of the first stage interference canceller. Based on the input signal vector X ₂ (t) from which interference waves have been removed with high accuracy without introduction, the interference canceller IC of the first-stage interference canceller renews the reception response vector H, the error determination signal E and the user The signal Y (t) is calculated and given to the second-stage interference canceller.

Arithmetic unit 10 of second stage interference canceller
2 'is a first stage interference canceller arithmetic unit 101'
And has exactly the same configuration as that of FIG. 10, and performs exactly the same operation as the operation described with reference to FIG. That is, only the replica signal corresponding to the user signal not including the demodulation error is subtracted from the initial input signal vector X ₁ (t), and the next input signal vector X ₃ (t) is output from the adder AD (FIG. 10). Will be done.

That is, the interference removal units IC ₁₁ ,.
For a user once determined that there is no error in IC _k1 ,..., IC _m1 , the replica signal is the initial input signal vector X ₁ (t) in any subsequent stage interference canceller.
To be subtracted from.

On the other hand, the interference removal units IC ₁₁ ,.
Even if the user is determined as having an error by IC _k1 ,..., IC _m1 and excluded from the subtraction from the initial input signal vector X ₁ (t) by the first stage interference canceller arithmetic unit 101 ′, Interference canceller IC of first stage interference canceller
_12, ..., IC _k2, ..., if it is determined that no error in any of the IC _{m @ 2,} the replica signal is also in the interference canceller of any stage of the subsequent initial input signal vector X ₁
It is the object of subtraction from (t).

As a result, in the arithmetic unit 102 'of the second-stage interference canceller, the input signal vector X from which the interference wave is removed with higher precision without introducing noise is obtained.
₃ (t) is obtained.

[0198] computing device 102 'operations of the interference canceller of the second stage comprising the arithmetic unit 101', the first gate unit _{GA 12, ..., GA k2,} ..., GA m2, interference removing unit IC _12,
.., IC _k2 ,..., IC _m2 , second gate part GB ₁₂ ,.
The operation is exactly the same as that of the above-described first-stage interference canceller composed of GB _k2 ,..., GB _m2 .

A plurality of such interference cancellers are connected in series, and only the replica signal of the user determined to have no error is subtracted from the initial input signal vector X ₁ (t) in the arithmetic unit of the interference canceller at each stage. By doing so, highly accurate interference wave removal can be performed in the interference canceller of each stage.

For a user once determined by the interference canceller IC in any of the stages including the preceding stage that there is no error, the received signal vector H calculated by the interference canceller IC, the error determination signal E, and the user signal Y (t) is output from a second gate section GB (not shown) of the final stage interference canceller, and the user signal Y (t) is extracted as a final error-free user signal and received. Will be output from the system.

On the other hand, the interference elimination units IC in all stages
, The received signal response vector H calculated by the interference canceller IC of the final stage interference canceller, the error determination signal E, and the user signal Y (t) are transmitted to the second gate GB. , And the user signal Y (t) is finally extracted as a user signal with an error and output from the receiving system.

The effect of the first embodiment will be described more specifically. In the first embodiment described above, for each stage of the multi-stage interference canceller, the arithmetic device converts the interference component corresponding to each (error-free) user, that is, a replica signal, from the initial input signal X ₁ (t) in the arithmetic unit. Configured to remove. According to the configuration of the first embodiment, the following effects can be obtained.

For example, out of four users, user 4
In the case of obtaining the received signal of
When it is determined by C ₁₁ and IC ₂₁ that only the users 1 and 2 have no demodulation error, only the replica signals of the users 1 and 2 are processed by the first stage interference canceller arithmetic unit 101 ′.
Is subtracted from the initial input signal vector X ₁ (t). As a result, the received signal X ₂ (t) for the user 4 of the first-stage interference canceller becomes the initial input signal− (the replica signal of the user 1 + the replica signal of the user 2).

Next, if it is determined in the interference canceller IC ₃₂ of the first stage interference canceller that there is no demodulation error for the user 3 in addition to the users 1 and 2, the second
In the arithmetic unit 102 'of the first stage interference canceller, the replica signals of the users 1, 2 and 3 are subtracted from the initial input signal X ₁ (t). As a result, the received signal X ₃ (t) of the second-stage interference canceller for user 4 is the initial input signal− (replica signal of user 1 + replica signal of user 2 + replica signal of user 3).

[Second Embodiment] FIG. 11 is a block diagram showing a receiving system of a PDMA base station according to a second embodiment of the present invention. The receiving system according to the second embodiment differs from the receiving system according to the first embodiment shown in FIG. 8 in which a replica signal is subtracted from the initial input signal vector X ₁ (t) in the arithmetic unit of the interference canceller at each stage. An interference component corresponding to each user, that is, a replica signal, is subtracted from an input signal vector newly calculated by the arithmetic unit of the interference canceller at the stage.

The receiving system according to the second embodiment shown in FIG. 11 differs from the receiving system according to the first embodiment shown in FIG. 8 in the following points. That is, the arithmetic unit 101 'in FIG. 11, gate unit GA _12, ..., GA _k2,
..., and GA _{m @ 2,} the interference removing unit IC _12, ..., IC _k2, ..., I
In the first-stage interference canceller composed of C _m2 , the input signal vector X ₂ (t) output from the arithmetic unit 101
Is given to the arithmetic unit 102 ″ of the second-stage interference canceller instead of X ₁ (t) in FIG.
In FIG. 1, the second gate unit GA of FIG. 8 is not provided, and the reception response vectors H,
The error signal E, the user signal Y (t), and the gate G
A, a reception response vector H, an error determination signal E, and a user signal Y that have passed from the interference canceller IC of the preceding stage via A
(T) are provided in parallel to the arithmetic unit 102 ″ of the second-stage interference canceller.

The arithmetic unit 102 ″ of the second stage interference canceller (and the arithmetic unit of the subsequent stages of the interference canceller) is not the configuration shown in FIG.
It has a configuration as shown in FIG.

In the arithmetic unit 102 ″ shown in FIG.
Interference canceller IC of a stage interference canceller, for example, interference canceller
Back IC₁₂Response vector H from₁₂, Error judgment signal
No. E ₁₂, And the user signal Y₁₂(T) and the previous stage
Interference remover IC₁₁From the first stage interference canceller
Received reception response vector H₁₁, Error determination signal E₁₁,
And user signal Y₁₁(T) is the gate portion GC₁Give to
Can be

[0209] The select control input gate unit GC _1, the error determination signal E ₁₁ is provided, the error determination signal E ₁₁ to indicate no error is found received signal response vector H ₁₁ from interference removing unit IC ₁₁ , An error determination signal E ₁₁ , and a user signal Y ₁₁ (t), and output as a received signal response vector H ₁₂ , an error determination signal E ₁₂ , and a user signal Y ₁₂ (t),
When the error determination signal E ₁₁ indicates that there is error, the reception signal response vector H ₁₂ from interference removing unit IC _12, the error determination signal E _12, and selects and outputs the user signal Y ₁₂ (t).

On the other hand, the reception response vector H ₁₂ from the interference canceller IC ₁₂ of the first-stage interference canceller and the user signal Y
₁₂ (t) is multiplied by the multiplier MP ₁ and the output is AN
Is supplied to one input of the D gate the AND _1. Also AND
To the other input of the gate the AND _1, the error determination signal E ₁₂ from interference removing unit IC ₁₂ is applied.

A gate section GD ₁ is provided between the AND gate AND ₁ and the adder AD, and the gate section GD ₁
Of the selection control input, the error determination signal E ₁₁ is applied. If the error determination signal E ₁₁ indicates no error, it does not give an output of the AND gate AND ₁ to the negative input of adder AD gate unit GD ₁ is closed. On the other hand, if the error determination signal E ₁₁ indicates there is an error, gate unit GD ₁ is opened AND
Providing an output of the gate the AND ₁ to the negative input of the adder AD.

The positive input of the adder AD is not the initial input signal vector X ₁ (t) as in the first embodiment, but the input signal vector X ₂ ( ₂ ) calculated by the arithmetic unit 101 ′ of the preceding stage interference canceller. t) is input.

The above is the description of the configuration corresponding to the user 1, but the arithmetic unit 102 ″ is assumed to include the same configuration from the user 1 to the user m.

The operation of the receiving system according to the second embodiment having the above configuration will be described.
₁ (t), the interference cancellers IC ₁₁ ,.
Among the C _k1 ,..., IC _{m 1} , for the user determined to have no error, the reception signal vector H calculated by the interference removal unit IC, the error determination signal E, and the user signal Y
(T) passes through the arithmetic unit 101 ′ of the first-stage interference canceller, the gate unit GA, and the gate unit GC of the arithmetic unit 102 ″ of the second-stage interference canceller as it is,
Gate GA of second stage interference canceller (not shown)
Given to.

That is, a user once determined that there is no error in the interference canceller IC at the preceding stage is not given to the interference canceller IC at the subsequent stage.

On the other hand, among the interference cancellers IC ₁₁ ,..., IC _k1 ,..., IC _{m1 in} the preceding stage that have received the input signal vector X ₁ (t), the user determined to have an error in the first stage Based on the input signal vector X ₂ (t) from which the interference wave has been removed with high accuracy without introducing noise in the interference canceller arithmetic unit 101 ′, the interference canceller IC of the first-stage interference canceller is renewed. A reception response vector H,
An error determination signal E and a user signal Y (t) are calculated,
The arithmetic unit 102 ″ of the second-stage interference canceller (FIG. 1)
Give to 2).

Arithmetic unit 10 of second stage interference canceller
In the case of 2 ", it is determined from the input signal vector X ₂ (t) output from the arithmetic unit 101 'of the preceding stage interference canceller that the demodulation error is not included in the interference canceller IC of the preceding stage (first stage) interference canceller. Only the replica signal corresponding to the determined user is subtracted from the input signal vector X ₂ (t).

Here, the interference removal units IC ₁₁ ,
..., IC _k1, ..., either in IC _m1, for example, with respect to the user 1, no error is determined by the interference removing unit IC _11, in the replica signal already arithmetic unit 101 ', the initial input signal vector X ₁ ( t), and is no longer included in the input signal vector X ₂ (t) provided to the adder AD of the arithmetic unit 102 ″. For the user 1 determined to have no such error, Is
The gate portion GA ₁₂ of the interference canceller of the first stage, the reception response vector H _11, which is the output of the preceding stage interference removing unit IC _11,
Error determination signal E _11, and the selected user signal Y ₁₁ (t) is output to the subsequent stage and further passes through the gate unit GC ₁ of the arithmetic device 102 ". Thus, the first stage corresponding to the user 1 X ₂ is used for the interference canceller IC ₁₂ of the interference canceller.
(T) is not given, and the received signal response vector H ₁₂ , the error determination signal E ₁₂ , and the user signal Y ₁₂ (t) are not output.

Therefore, for user 1 already determined to have no error, multiplier MP ₁ , AND gate AN
The operation by D ₁ is not performed and is excluded from the subtraction from the input signal vector X ₂ (t) by the adder AD. However, even if the input X ₂ (t) to the interference elimination unit IC ₁₂ is 0, some noise is generated by the operation of the interference elimination unit IC ₁₂ , and the addition is performed via the multiplier MP ₁ and the AND gate AND ₁ . to prevent the input to the AD, a gate unit GD ₁ with respect to user 1, no error is determined is closed and the output from the aND gate aND ₁ to adder AD is completely shut off.

The effect of the second embodiment will be described in more detail. According to the second embodiment, the interference canceller of each stage converts the replica signal from the input signal vector calculated by its own arithmetic unit. It is configured to be removed by the next-stage arithmetic unit.

For example, out of four users, user 4
In the case of obtaining the received signal of
When it is determined that only the users 1 and 2 have no error in the C ₁₁ and the IC ₂₁ , the received signal vector X ₂ (t) relating to the user 4 of the first-stage interference canceller is represented by an initial input signal− (replica of the user 1) (Signal + replica signal of user 2).

Next, in the second embodiment, the received signal for user 4 in the second-stage interference canceller is X ₂ (t) − (replica signal of user 3).

That is, in the first embodiment, since the arithmetic unit of the interference canceller at each stage subtracts the replica signal from the initial input signal vector X ₁ (t), the subtraction is performed once without error. The user's replica signal also needs to be repeatedly subtracted from the input signal vector in each subsequent stage. In the second embodiment, the user who has already been subtracted from the input signal vector as having no error is no longer input in the subsequent stage. There is no need to redo the subtraction from the signal vector. Therefore, the second embodiment
Thus, the amount of calculation processing can be significantly reduced.

[Third Embodiment] FIG. 13 is a block diagram showing a receiving system of a PDMA base station according to a third embodiment of the present invention. In the third embodiment, basically, the signal Y of the user k detected from the received signal vector X _1k (t) used for the signal detection of the user k in the k-th stage interference canceller IC _1k in the vertical direction. _The signal vector obtained by subtracting the value obtained by multiplying _1k (t) by the reception response vector H _1k output from the parameter estimator is used as the (k + 1) th stage interference canceller IC _{1 (k By using} the input signal vector X _{1 (k + 1)} (t ₎ of the adaptive array of _{( +1)} , the user signal Y _{1 (k + 1)} (t) is more accurately extracted in the interference canceller of the next stage. It is like that.

That is, the input signal vector X ₁₁ (t) output from the A / D converter 8 is given to the first stage interference canceller IC ₁₁ . In FIG. 13, the interference removing unit IC
All have the same configuration. As an example, FIG. 14 shows the configuration of the interference removal unit IC _1k .

Referring to FIG. 14, interference canceller IC at the preceding stage
_The input signal vector X _1k (t) given from _{1 (k−1} ) is
The signal is input to the adaptive array AA _1k and is also _{supplied to} the positive input of the adder AD _1k and the parameter estimator PE _1k . A user signal Y, which is a complex signal, is _derived from the input signal vector X _1k (t) by the adaptive array AA _1k .
_1k (t) is extracted and converted to a bit information signal by the demodulator DM _1k . This bit information signal is provided to the error determiner ED _1k and also to the re-modulator RM _1k . The error determiner ED _1k determines the presence or absence of a demodulation error of the signal extracted from the adaptive array AA _1k based on the given bit information signal. If it is determined that there is an error, an L-level error determination signal E _1k is generated and output to the outside. The re-modulator RM _1k converts the given bit information signal again into a user signal Y which is a complex signal.
Convert to _1k (t) and output. This user signal Y
_1k (t) is _supplied to the parameter estimator PE _1k and the multiplier MP _1k and is output to the outside.

The parameter estimator PE _1k estimates the reception response vector H _1k based on the detected user signal Y _1k (t) and the input signal vector X _1k (t). Then, multiplier MP _1k receives reception response vector H _1k and user signal Y
_1k (t) and the result is applied to the negative input of the adder AD _1k . Note that an AND gate AND _1k is provided between the multiplier MP _1k and the adder AD _1k, and one input of which is _{supplied with an} error determination signal E _1k from the error determiner ED _1k .

Referring to FIG. 13, interference cancellers IC ₁₁ ,..., IC _1m are connected in series in the vertical direction corresponding to users ₁ to m, and these m interference cancelers are arranged in the first stage. It is assumed that the interference canceller is configured. The interference eliminator IC of each stage is configured in the same manner as the interference eliminator of the k-th stage in FIG. 14, and the description thereof will not be repeated.

Next, the basic operation of the third embodiment shown in FIGS. 13 and 14 will be described. Equations (41) to (45) described in connection with the receiving system of the present invention in FIGS. 6 and 7 are also applied to the third embodiment.

First, the k-th stage interference canceller IC_1kOutput unit
User signal is Y_1k(T). Parameter estimator PE_1k
Is the user signal Y of the user k_1k(T) and input signal vector
Le X _1kFrom (t), the reception response vector H of the user k is obtained._1k
Is output. And the multiplier MP_1kThe user signal Y
_1k(T) and reception response vector H_1kAnd multiply by
Is the adder AD_1kThe input signal vector X_1kFrom (t)
Subtract. The result is given to the next stage interference elimination unit IC._{1 (k + 1)}What
Input signal vector X_{1 (k + 1)}(T). That is,
The following equation is obtained.

X _{1 (k + 1)} (t) = X ₁ (t) −H _1k S _1k (t) (49) By substituting the above-mentioned equation (43) into this equation (49),
Equation (50) is obtained.

X _{1 (k + 1)} (t) = ｛H _1k Y _1k (t) + H _{1 (k + 1)} Y _{1 (k + 1)} (t) +... + H _1m Y _1m (t) + N ( t)｝ − H _1k Y _1k (t) = H _{1 (k + 1)} Y _{1 (k + 1)} (t) +... + H _1m S _1m (t) + N (t) (50)

As understood from the equation (50),
The input vector signal X _{1 (k + 1)} (t) is obtained by _converting the input signal vector X _1k (t) of the preceding stage interference canceller into the user signal Y 1
This is a vector signal from which the _1k (t) component (that is, the interference signal component for the adaptive array AA1 _{(k + 1) of the (k + 1) th} stage interference removal unit) has been removed. Therefore,
Adaptive array AA of the (k + 1) th stage interference canceller
_As an input signal vector of _{1 (k + 1)} , X is larger than X _1k (t).
_{Using 1 (k + 1)} (t) allows the adaptive array to work better, resulting in a more accurate user (k +
The signal Y _{1 (k + 1)} (t) of ₁₎ can be extracted.

Embodiment 3 shown in FIGS. 13 and 14
When the user signal extracted by the adaptive array AA _1k at each stage (for example, the k-th stage) of the first-stage interference canceller includes a demodulation error, the error determiner ED _1k outputs an L-level error. A determination signal E _1k is generated and applied to one input of an AND gate AND _1k . As a result, the reception response vector H output from the multiplier MP _1k
The product of _1k and the user signal Y _1k (t), that is, the input of the replica signal to the adder AD _1k is blocked.

As a result, the adders AD ₁₁ ,.
_1k ,..., AD _1m , the subtraction of the extracted user signal including the error is excluded, and such an error is reflected in the subtraction result of each stage (for example, impulse). (Noise noise). Therefore, it is possible to prevent the user signal output from each stage from being affected by the demodulation error.

As described above, the interference elimination units IC ₁₁ ,.
In the first-stage interference canceller composed of a series connection of C _1m, the removal of the interference wave is stopped in the interference removal unit in which the error is determined, so it is not necessarily sufficient in terms of removing the interference wave component. However, once the user signal including the demodulation error is subtracted, the user output signals in all the subsequent stages are affected by the subtraction and become incorrect output signals. In view of such a drawback, even if the removal of the interference wave component becomes slightly insufficient, the interference canceller including the k-stage interference canceller in the vertical direction is not suitable for securing the effectiveness of the output user signal. It is considered to be sufficiently effective.

However, the third embodiment shown in FIG.
In order to further promote the removal of the interference wave component, FIG.
Interference removing unit IC ₁₁ in the longitudinal direction of the k-th stage shown in 3, ..., IC
A series connection of 1 _m is used as a first-stage interference canceller, which is connected in a plurality of stages in the horizontal direction to constitute a multi-stage interference canceller. Thereby, it is possible to further remove the interference wave component for the processing in the subsequent stage.

That is, each stage corresponding to the plurality of users 1 to m, for example, the first stage in the vertical direction, the interference canceller I
The error determination signal E ₁₁ output from C _{11 is} output to the first-stage gate unit GE ₂₁ of the next-stage interference canceller adjacent in the horizontal direction.
And the gates GF ₂₁ and G
It is given to the select input of the G _21. In addition, the interference removal unit I
The user signal Y ₁₁ (t) output from C _{11 is} also applied to the gate section G.
It is applied to the input of the E _21.

[0239] Also, applied to the input of the input signal vector X ₂₁ (t) be the gate portion GE ₂₁ from interference removing unit IC _{1 m} in the final stage of the interference canceller of the first stage.

Error determination signal E₁₁But the interference removal unit IC₁₁
If it indicates that there was no demodulation error in
Port GE_{twenty one}Is the input error determination signal E₁₁According to
And the error determination signal E₁₁Itself and user signal Y
₁₁(T) as it is, and the gate portion GF_{twenty one}To input
And input signal vector X_{twenty one}Gate (t)
Part GG _{twenty one}Give to the input.

[0241] On the other hand, the error determination signal E _{1 1} is, indicating that had been in there demodulation error at the interference removing unit IC _11, the gate unit GE ₂₁ is the error determination signal E ₁₁ input
, The input signal vector X ₂₁ (t) is converted to the interference canceling unit I
Give to the input of the C _21.

The interference elimination unit IC ₂₁ has the same configuration as the interference elimination unit IC _1k shown in FIG. 14, and provides the calculated error determination signal E ₂₁ and user signal Y ₂₁ (t) to the input of the gate unit GF _21. , The input signal vector X ₂₂ (t) to the gate unit GG
Give to ₂₁ inputs.

Gate GF_{twenty one}Is the error determination signal E₁₁But
If no error is indicated, the interference canceller IC in the preceding stage₁₁Or
Gate part GE_{twenty one}Error determination signal E that has passed₁₁and
User signal Y₁₁Select (t) and judge each error
Signal E_{twenty one}And user signal Y _{twenty one}Output as (t).

[0244] On the other hand, the gate unit GF _21, when the error determination signal E ₁₁ indicates that there is error, error is newly calculated by the interference removing unit IC ₂₁ determination signal E ₂₁ and user signal Y ₂₁ (t) is Select and output as is.

[0245] The gate portion GG _21, when the error determination signal E ₁₁ indicates that there is no error, select the input signal vector X ₂₁ passing through the gate unit GE ₂₁ from the interference removing unit IC _1m (t), subsequent give of the input of the gate unit GE _22.

[0246] On the other hand, the gate unit GG _21, when indicating that there is an error the error determination signal E _11, select the newly calculated input signal vector X ₂₂ (t) by the interference removing unit IC _21, the subsequent stage give of the input of the gate unit GE _22.

[0247] That is, once it is determined no error by the interference removing unit IC ₁₁ of the preceding stage interference canceller, the error calculated by the interference removing unit IC ₁₁ determination signal E ₁₁ and the user signal Y ₁₁ (t) is, as it The signal passes through the interference cancellers connected in a plurality of stages in the horizontal direction, and is output as a final output from a gate GF (not shown) of the final stage interference canceller. Also, the input signal vector X ₂₁ from the previous stage
(T) is directly gate portion G without passing through the interference removing unit IC ₂₁
It is applied to the input of the G _21.

[0248] On the other hand, if it is determined that there is an error by the interference removing unit IC ₁₁ of the preceding stage interference canceller is prohibited subtraction from the input signal vector of the replica signal corresponding to user 1, interference removing unit IC ₁₁ Therefore, the input signal vector X ₂₁ (t) input to the interference canceller IC ₂₁ still includes the interference component of the user 1. Therefore,
Interference removing unit IC _21, the input signal vector X interference wave component has been already removed for the user of the error-free
Based on ₂₁ (t), the interference wave component of the user 1 is removed again. FIG. 14 shows the operation of the interference removal unit IC ₂₁ .
Has already been described with reference to FIG.

First-stage interference canceller I corresponding to user 1
The gate unit GE (Fig error determination signal E ₂₁ indicating the presence or absence of a demodulation error in the user signal Y ₂₁ (t) and the interference removing unit IC ₂₁ output from the C ₂₁ via the gate unit GF ₂₁ next stage interference canceller (Not shown). Also, depending on the presence or absence of errors in the preceding stage interference removing unit IC _11, the gate unit GE ₂₁ from the newly calculated input signal vector X ₂₂ (t) or the preceding stage interference removing unit IC _{1 m} in the interference removing unit IC ₂₁ The input signal vector X ₂₁ (t) output as it is via the gate section GE ₂₂ at the subsequent stage.
This input signal vector X ₂₂ (t) is transmitted to the interference removal unit IC ₁₂
It brought further passed to the next stage through gate unit GG ₂₂ without passing either given to the interference removing unit IC _22, or the interference removing unit IC ₂₂ in accordance with the presence or absence of errors in.

The configuration and operation of the second stage corresponding to user 2 are the same as the configuration and operation of the first stage corresponding to user 1 described above.

As described above, according to the third embodiment of the present invention, an interference carrier composed of m stages of interference cancellers corresponding to users 1 to m connected in series in the vertical direction is By providing a plurality of stages, it is possible to further remove the interference wave component.

[Embodiment 4] FIG. 15 is a block diagram showing a receiving system of a PDMA base station according to Embodiment 4 of the present invention. The configuration of the receiving system shown in FIG. 15 is the same as the receiving system of the first embodiment shown in FIG. 8 except for the following points.

That is, in Embodiment 1 of FIG. 8, the user signal which is a complex signal output from the re-modulator (FIG. 9) included in each interference elimination unit IC is included in the interference elimination unit. Although it is only given to the parameter estimator (FIG. 9) and not given to the parameter estimator of the interference elimination unit of another user, in the fourth embodiment of FIG. The user signal output from the modulator is
It is configured to be provided to the parameter estimators of the interference canceling units of all other users in addition to the user.

As described in connection with the receiving system of the present invention shown in FIG. 6, the correlation value between the user signal of the user and the user signal of another user is not considered at all (the correlation value is Estimating the received response vector (assuming 0) causes an error to be included in the output signal.

In the fourth embodiment shown in FIG. 15, the reception response vector of each user is to be estimated in consideration of the correlation value between a plurality of user signals, and the calculation method will be described below.

For example, signals Y of four users
_{Based on 11} (t), Y ₂₁ (t), Y ₃₁ (t), Y ₄₁ (t) and the reception response vectors H ₁₁ , H ₂₁ , H ₃₁ , H ₄₁ , the received signal X ₁ (t) becomes Shall be defined as follows.

X ₁ (t) = (H ₁₁ * Y ₁₁ (t)) + (H ₂₁ * Y ₂₁ (t)) + (H ₃₁ * Y ₃₁ (t)) + (H ₄₁ * Y ₄₁ (t )) + N (51) where n is a noise component.

Here, the user signal Y ₁₁ (t) of the user 1
And an ensemble average of the received signal X ₁ (t) and
Equation (11) is expanded as follows. The superscript * represents a complex conjugate.

E [X ₁ (t) * Y ₁₁ ^* (t)] = H ₁₁ * E [Y ₁₁ (t) * Y ₁₁ ^* (t)] + H ₂₁ * E [Y ₂₁ (t) * Y _{11 ^{* (t)] + H 31}} * E [Y 31 (t) * Y 11 * (t)] + H 41 * E [Y 41 (t) * Y 11 * (t)] + E [n * Y 11 * (t )] (52) where E [Y ₁₁ (t) * Y ₁₁ ^* (t)] = 1, [n * Y
_{Since 11} ^* (t)] = 0, the expression (52) is as follows.

E [X₁(T) * Y₁₁ ^*(T)] = H₁₁+ H_{twenty one}* E [Y_{twenty one}(T) * Y₁₁ ^*(T)] + H₃₁* E [Y₃₁(T) * Y_{1 1} ^* (T)] + H₄₁* E [Y₄₁(T) * Y₁₁ ^*(T)] (53) A receiving system which is a premise of the present invention shown in FIGS. 6 and 7
Is a correlation value between user signals, E [Y_{twenty one}(T) * Y₁₁
^*(T)], E [Y₃₁(T) * Y₁₁ ^*(T)], E [Y₄₁
(T) * Y₁₁ ^*(T)] in the actual propagation environment.
Although it was set to 0 despite the fact that there was, as a result
E [X₁(T) * Y₁₁ ^*(T)] = H₁₁Contains errors
However, in the fourth embodiment, between these users
Receive after calculating the correlation value (ensemble average)
Response vector H₁₁, H_{twenty one}, H₃₁, H ₄₁Is calculated.
The following calculation is performed, for example, in the preceding stage₁₁,…,
IC _k1, ..., IC_m1Then, the parameter estimator PE₁₁,
…, PE_k1, ..., PE_m1Performed by

That is, the reception response vectors H ₁₁ , H ₂₁ ,
Assuming that H ₃₁ and H ₄₁ are unknowns, 4
A simultaneous equation consisting of two equations is required. Therefore,
In addition to the value of E [X ₁ (t) * Y ₁₁ ^* (t)], 3
Average of two ensembles, ie, E [X ₁ (t) * Y ₂₁ ^*
(T)], E [X ₁ (t) * Y ₃₁ ^* (t)], E [X
₁ (t) * actually calculate also the value of Y ₄₁ ^* (t)].

Then, individual correlation values between user signals (en
Ensemble average) and calculate the above three ensembles
Substituting the result into the expansion result of the Bull₁₁,
H_{twenty one}, H ₃₁, H₄₁The simultaneous equation is completed, and this
By solving the
Kutor H₁₁, H_{twenty one}, H₃₁, H₄₁Is estimated with high accuracy.
Can be. And also in the next stage interference canceller
Similarly, actually calculate the correlation value between the user signals and receive
Estimating the vector.

In each stage of the interference canceller,
Even if it is determined that there is no error in the interference canceller in the preceding stage and the replica signal has already been subtracted once, the subtraction of the replica signal from the initial input signal vector is performed again, thereby improving the accuracy of the elimination. For the purpose, a separate parameter estimator _{PEA 12, ..., PEA k2,} ..., PEA m2 are provided.

In particular, in the fourth embodiment, regardless of the result of the demodulation error determination of the extracted signal by the error determiner,
Individual correlation values between all users (ensemble average)
Is actually calculated and used. Therefore, it is conceivable that a demodulation error has occurred for any of the users. However, the correlation value between the signal having an error and the signal having no error is equal to the actual signal (the signal having no error and the signal having no error). ), It is possible to estimate a reception response vector close to the actual propagation environment.

As described above, according to the fourth embodiment of the present invention, since the correlation value between user signals, which was conventionally regarded as 0, is actually calculated, an error-free reception response vector is estimated. It becomes possible.

[Fifth Embodiment] FIG. 16 is a block diagram showing a receiving system of a PDMA base station according to a fifth embodiment of the present invention. The configuration of the receiving system shown in FIG. 16 is different from that of the receiving system shown in FIG.
Is the same as the receiving system.

That is, in addition to the configuration of the fourth embodiment shown in FIG. 15, in FIG. 16, the configuration is such that the error determination signal of the error determiner of each user is given to the parameter estimators of the interference cancellers of all users. Have been. As a result, it is possible to determine whether to calculate a correlation value between signals based on the presence or absence of a demodulation error.

A more specific description will be given using the example of the fourth embodiment. For example, it is assumed that out of four users, it is determined that there is no demodulation error in the extracted signals of users 1 and 2 and that there is a demodulation error in the extracted signals of users 3 and 4. With respect to the signal of the user having an error, the user signal is extracted again by the next stage interference canceller.

Therefore, in the fourth embodiment, the error
Using only the correlation of the signals of users 1 and 2 without
Correlation with signals of users 3 and 4 with errors is assumed to be 0
No. For example, in equation (13) above, the correlation
E [Y₃₁(T) * Y ₁₁ ^*(T)] and E [Y
₄₁(T) * Y₁₁ ^*(T)] is regarded as 0. Therefore,
Equation (53) is as follows.

E [X ₁ (t) * Y ₁₁ ^* (t)] = H ₁₁ + H
₂₁ * E [Y ₂₁ (t) * Y ₁₁ ^* (t)]

In this equation, since there are two unknowns, H ₁₁ and H ₂₁ , in addition to the value of E [X ₁ (t) * Y ₁₁ ^* (t)], E [X ₁ (t) * Y ₂₁ ^* (t)] is also calculated.
Then, the correlation value E [Y ₂₁ (t) * Y of the users 1 and 2
₁₁ ^* (t)] and E [X ₁ (t) * Y ₁₁ ^* (t)]
And E [X ₁ (t) * Y ₂₁ ^* (t)], a simultaneous equation with unknowns as H ₁₁ and H ₂₁ is completed, and by solving this, the reception response vector H
The _11, H ₂₁ can be calculated with high accuracy.

Particularly, in the fourth embodiment, it is possible to estimate a reception response vector closer to an actual propagation environment by actually calculating and using a correlation value between user signals without errors.

[Embodiment 6] FIG.17 is a block diagram showing a receiving system of a PDMA base station according to Embodiment 6 of the present invention. The configuration of the receiving system shown in FIG. 17 is different from that of the second embodiment shown in FIG. 11 except for the following points.
Is the same as the receiving system.

That is, in the second embodiment shown in FIG. 11, a user signal which is a complex signal output from a remodulator included in each interference canceller IC is transmitted to a parameter estimator included in each interference canceller. 17 is not provided to the parameter estimator of the interference removal unit of another user. However, in the sixth embodiment of FIG. 17, the fourth embodiment of FIG.
Similarly to the above, the user signal output from the re-modulator of the interference canceller of each user is configured to be provided to the parameter estimators of the interference cancelers of all other users in addition to the user. .

The receiving system according to the sixth embodiment shown in FIG. 17 differs from the receiving system according to the fourth embodiment shown in FIG. 15 in the following points.

First, in the configuration of the sixth embodiment shown in FIG.
A subtraction of a replica signal of a user newly determined to have no error is performed from the input signal vector calculated by the arithmetic unit of the interference canceller instead of the initial input signal vector X ₁ (t). That is, for the user who has already determined that there is no error in the interference canceller at the preceding stage, the subtraction of the replica signal is not performed again.
Parameter estimation unit PEA ₁₂ as, ..., PEA _k2,
... It is not necessary to add PEA _m2 .

Instead, depending on whether or not there is an error in the interference canceller at the preceding stage, either the user signal newly calculated by the interference canceller of the interference canceller or the user signal already calculated by the interference canceller at the preceding stage is used. GH ₁₂ ,..., GH _k2,.
H _m2 is provided.

As described above, according to the sixth embodiment of the present invention, the correlation value between user signals which was conventionally regarded as 0 is actually calculated. , An error-free reception response vector can be estimated.

[Seventh Embodiment] FIG. 18 is a block diagram showing a receiving system of a PDMA base station according to a seventh embodiment of the present invention. The configuration of the receiving system shown in FIG. 18 is different from that of the sixth embodiment shown in FIG. 17 except for the following points.
Is the same as the receiving system.

That is, in addition to the configuration of the sixth embodiment shown in FIG. 17, in FIG. 18, the configuration is such that the error determination signal of each user's error determiner is provided to the parameter estimators of the interference cancellers of all users. Have been. As a result, it is possible to determine whether to calculate a correlation value between signals based on the presence or absence of a demodulation error.

That is, in the seventh embodiment, as in the fifth embodiment described above, by actually calculating and using a correlation value between error-free user signals, a reception response closer to an actual propagation environment is obtained. It is possible to estimate a vector.

[Eighth Embodiment] FIG. 19 is a block diagram showing a receiving system of a PDMA base station according to an eighth embodiment of the present invention. The receiving system according to the eighth embodiment basically applies the technology described in the fourth embodiment in FIG. 15 to the configuration of the receiving system in the third embodiment shown in FIG.

That is, in Embodiment 3 of FIG. 13, a user signal which is a complex signal output from a re-modulator (FIG. 14) included in each interference canceller is provided to a parameter estimator of the interference canceller. However, in the eighth embodiment of FIG. 19, the user signal output from the remodulator of each user is added to the parameters of the other users. Thus, it is also configured to be provided to the parameter estimator of the interference elimination unit of the user at the next and subsequent stages.

More specifically, the embodiment shown in FIG.
In state 8, the initial input signal vector X ₁(T) is each interference
The signal is applied to the removal unit IC in common, and as described later, each interference removal is performed.
Correction of the parameter estimator PE and adder AD of the back IC
Assume that it is given to the input. And the previous stage interference
The input signal vector output from the canceller is
Given to the adaptive array AA at the back (first stage
Interference removal unit IC₁₁Then, the initial input signal vector X
₁(T) is adaptive array AA₁₁Given to you).

The interference canceller I of the first-stage interference canceller
At C ₁₁ , as shown in FIG. 14, the user signal Y ₁₁ (t) generated by the interference canceller is converted to a parameter estimator P.
The parameter is estimated by giving it to E _1k , and the user signals of other users are not used.

[0286] However, in the later stage of the interference removing unit IC _12, in addition to the user signal Y ₁₂ generated in the interference removing unit (t), the user signals Y ₁₁ generated by the preceding stage interference removing unit IC ₁₁ (t) Is used to estimate parameters.

Similarly, the interference elimination unit of each stage estimates parameters using the user signal from the interference elimination unit preceding the interference elimination unit in addition to the user signal generated by the interference elimination unit. I have.

For example, the lowermost stage interference canceller IC _1m of the first stage interference canceller includes, in addition to the user signal Y _1m (t) generated by the interference canceller, the preceding stage interference canceller IC
₁₁ ,..., User signal Y generated in IC _{1 (m -1)
11} (t),..., Y _{1 (m-1)} (t) are used to estimate parameters.

As an example of the interference canceller shown in FIGS. 20 and 19, the interference canceller I at the k-th stage of the first-stage interference canceller is used.
It is a block diagram which shows the structure of _C1k . The interference canceller shown in FIG. 20 differs from the interference canceller shown in FIG. 15 in the following points.

That is, the input signal vector X _1k (t) output from the interference canceller at the preceding stage is
A _1k only, and the initial input signal X ₁ (t)
Is applied to the input of the parameter estimator PE _1k and the positive input of the adder AD _1k . In addition to the user signal Y _1k (t) generated by the interference canceller, the parameter estimator PE _1k adds the user signal Y ₁₁ (from the preceding interference cancellers IC ₁₁ ,..., IC _{1 (k-1)).} t),..., Y _{1 (k-1)} (t) are also given,
Based on the correlation values of these user signals, the parameter estimator PE _1k receives the reception response vectors H ₁₁ , H _{12 ,.}
Is calculated.

These user signals Y ₁₁ (t),..., Y _1k
(T) and the reception response vectors H ₁₁ ,..., H _1k are respectively multiplied by corresponding multipliers MP _1k1 , MP _1k2 ,..., MP _1kk , and the multiplication results are AND gates AND _1k1 , AND _1k2 , respectively. .., AND _1kk are _supplied to the negative input of the adder AD _1k .

The AND gates AND _1k1 , AND _{1k2 ,.}
The other input of AND _1kk is connected to the interference canceller IC ₁₁ in the preceding stage,
..., the error determination signal E ₁₁ from _{IC 1 (k-1),} ..., E
_{1 (k-1)} and the error determination signal E _1k generated by the interference canceller are input, and the AND gate to which the error determination signal indicating the presence of the error is input is closed and the initial input signal vector of the replica signal including the error is closed. Subtraction from X ₁ (t) is avoided.

As a result, the adder AD_1kFrom the noise component
Input signal vector X that does not include the minute_{1 ( k + 1)}(T) is calculated
The next stage interference elimination IC_{1 (k + 1)}Adaptive Array
AA _{1 (k + 1)}Given to.

The interference cancellers IC ₂₁ , IC ₂₂ ,... Of the second and subsequent interference cancellers have the same configuration.

That is, in the examples of FIGS. 19 and 20,
Interference removing unit IC _11, ..., reception response vector H _{1 1,} H ₁₂ in the _{IC 1m, ..., H 1k,} ..., H 1m is obtained as follows. First, the initial input signal vector X ₁ (t) is expressed as follows.

X ₁ (t) = H ₁₁ Y ₁₁ (t) +... + H _1k Y
_1k (t) +... + H _1m Y _1m (t) In the configuration of the first-stage interference canceller in FIG. 19, the interference canceller IC at each stage uses the user signal Y based on the initial input signal vector X ₁ (t). _1k (t) can be estimated. Therefore, each user signal and the initial input signal vector X
Taking the ensemble average of the ₁ (t), received on the calculated correlation value between users (ensemble average) actual response vectors _{H 11, H 12, ...,} H 1k, ..., for determining the H _{1 m} A simultaneous equation is obtained.

Furthermore, the operation of the interference canceller at the next stage is basically the same as the operation described with reference to FIG. 13, and the following points are different.

That is, the gate section GE ₂₁ receives the user signal Y from the preceding stage interference canceling sections IC ₁₂ ,..., IC _{1m.
12 (t), ..., Y} 1m (t) and the error determination signal E _12,
..., it is given a E _{1 m,} when the error is determined by the interference removing unit IC _11, these user signals Y
_{12 (t), ..., Y} 1m (t) and the error determination signal E _12,
.., E _1m are given to the interference canceller IC _21, and the user signals among them are used for parameter estimation.

Next, the gate portion GE_{twenty two}In the previous stage,
Back IC₁₃, ..., IC_1mAnd IC _{twenty one}From the user signal
Y₁₃(T), ..., Y_1m(T), Y_{twenty one}(T) and error
Judgment signal E₁₃, ..., E_1m, E_{twenty one}Is given and interference
Removal unit IC₁₂If an error is determined in
User signal Y₁₃(T), ..., Y_1m(T), Y_{twenty one}(T)
And error determination signal E₁₃, ..., E_1m, E_{twenty one}Is the interference removal unit
IC_{twenty two}Of which the user signal is the parameter
Used for estimation. Below, the interference of each stage of the interference canceller
The same operation (parameter estimation) is performed in the removal unit.
It is.

As described above, the receiving system according to the eighth embodiment of FIG. 19 attempts to calculate the reception response vector of each user in consideration of the correlation value between a plurality of user signals. Therefore, the receiving system according to the eighth embodiment can estimate a received signal response vector close to that obtained in an actual propagation environment with high accuracy, similarly to the receiving system according to the fourth embodiment.

[Embodiment 9] FIG.21 is a block diagram showing a configuration of an interference canceller in a receiving system of a PDMA base station according to Embodiment 9 of the present invention. The receiving system according to the ninth embodiment basically has the same overall configuration as that of the receiving system shown in FIG. 19 except for the configuration of the interference canceller. The technology described in the fifth embodiment in FIG. 17 is applied to the system configuration. The interference elimination section shown in FIG. 21 is different from the interference elimination section shown in FIG.
This is the same as the interference removal unit.

That is, in addition to the configuration of the interference canceller of the eighth embodiment of FIG. 20, in the ninth embodiment of FIG. 21, an error judgment signal (eg, E ₁₁ ,. E _{1 (k-1)} ) is provided to a parameter estimator of the interference canceller at the next stage.

The receiving system according to the ninth embodiment shown in FIG. 21 determines whether to calculate a correlation value between signals based on the presence or absence of a demodulation error. In particular, in the receiving system according to the ninth embodiment, a correlation value is calculated only between user signals having no error and used for calculating a received signal response vector. In addition, a reception response vector close to that obtained in an actual propagation environment can be estimated with high accuracy.

[Embodiment 10] By the way, FIGS.
The embodiment shown in FIG. 1 relates to a receiving system of a PDMA base station. In recent years, in addition to this PDMA communication system, a CDMA communication system has been proposed and has already been put to practical use.

In this CDMA communication system, the transmitting side multiplies a symbol of digital data to be transmitted by a predetermined spreading code and transmits it as a signal of a much higher frequency, and the receiving side uses the spreading code to receive a received signal. Is demodulated by despreading the data.

Here, if a plurality of types of spreading codes having no correlation with each other are used, even if a plurality of data signals of the same frequency are spread and transmitted,
By performing despreading with a spreading code corresponding to transmission, it is possible to reliably separate and extract only a signal of a desired user. Therefore, by using this CDMA communication system, it is possible to further increase the communication capacity. Such a CDMA communication system has already been put into practical use,
The detailed description is omitted because it is well known in the art.

In the embodiments described below, the radio receiving system according to the present invention is applied to a CDMA communication system.

FIG. 22 is a block diagram showing a receiving system of a CDMA base station according to Embodiment 10 of the present invention. FIGS. 23 and 24 are diagrams of an interference canceling unit and an arithmetic unit shown in FIG. 22, respectively. It is a specific block diagram.

Embodiment 10 shown in FIGS. 22 to 24
Is the same as the PDMA receiving system of the first embodiment shown in FIGS. 8 to 10 except for the following points.

That is, the configuration of the interference canceller IC of the receiving system of the first embodiment shown in FIG. 8 was changed from the configuration of the first embodiment shown in FIG. 9 to the configuration of the tenth embodiment shown in FIG. Things. An interference canceling unit (an interference canceling unit IC _K1 ′ as an example) shown in FIG. 23 despreads a signal transmitted by the CDMA communication method and received by the antennas 3 to 6 at a stage preceding the adaptive array and the parameter estimator. A despreader IS _k1 is provided. The received signal despread for each user by the despreader in each interference canceling unit is provided to the corresponding adaptive array and parameter estimator, and by the same operation as in the first embodiment,
Each user signal is extracted and provided to the operation unit of the subsequent interference canceller.

The arithmetic unit 101a of the first-stage interference canceller shown in FIG. 24 includes multipliers MP ₁ ,..., MP _k−1 , M
_{P k, MP k + 1,} ..., diffuser S ₁₁ for spreading the outputs of the _{MP m, ..., S (k1} ) 1, S k1, S (k + 1) 1, ..., S m1 is provided The arithmetic unit 1 shown in FIG.
Same as 01 '.

That is, in order to perform subtraction from the input signal vector X ₁ (t) which has been spread by the CDMA communication system, the output of each multiplier is spread again by the corresponding spreading code.

The output of each spreader, that is, the output of the arithmetic unit 101a, is despread again by the despreader of the corresponding interference elimination unit at the subsequent stage, and supplied to the adaptive array and the parameter estimator.

Arithmetic unit 102 of second stage interference canceller
a has the same configuration as the arithmetic unit 101a shown in FIG. Other operations are the same as those of the first embodiment shown in FIGS.

[Embodiment 11] FIG.25 is a block diagram showing a receiving system of a CDMA base station according to Embodiment 11 of the present invention. Embodiment 11 shown in FIG. 25 is the same as Embodiment 3 shown in FIG. 13 except for the following points. That is, a despreader for despreading the input signal vector transmitted by the CDMA communication method is provided before the corresponding adaptive array and parameter estimator for each stage of the interference canceller (interference canceller IC in FIG. 14). _{At 1k} ', a despreader IS _1k ) is provided. The input signal vector despread for each user in each despreader is provided to the corresponding adaptive array and parameter estimator, and the respective user signals are extracted by the same operation as in the third embodiment. The output of the multiplier in each interference canceling unit is spread again by a spreader (spreader S _{1k in} FIG. 14) in order to perform subtraction from the corresponding input signal vector that has been spread by the CDMA method. Other operations are the same as those of the third embodiment shown in FIG. 13, and thus will not be repeated here.

[0316] Examples in which the CDMA communication system is applied to the first embodiment shown in Figs. 8 to 10 and the third embodiment shown in Figs. 13 and 14 have been described as the tenth and eleventh embodiments. For the receiving system disclosed as another embodiment, the CD
It goes without saying that the M communication system is similarly applied.

FIG. 26 is a block diagram showing an example of an adaptive array used in the receiving systems of the above embodiments.

In FIG. 26, each adaptive array is provided with input ports 181 to 184, and each input port receives signals from four antennas 3 to 6 A / D-converted by the A / D converter 8. Is input. These input signals are provided to weight vector calculator 176 and multipliers 171 to 174.

The weight vector calculator 176 uses the input signals from the input ports 181 to 184 and the training signal corresponding to the specific user signal stored in the memory 177 or the output of the adder 175 to obtain a desired signal. Weight vector w1 such that the user signal of
〜W4 is calculated.

The multipliers 171 to 174 are connected to the input port 18
The input signals of Nos. 1 to 184 are multiplied by the weight vectors w1 to w4, respectively, and output to the adder 175. Adder 1
The adder 75 adds the respective output signals of the multipliers 171 to 174 and supplies a desired user signal obtained as a result to the weight vector calculator 176 and outputs it from an output port.

In the first to eleventh embodiments, the data re-modulated by the re-modulator is provided to the arithmetic unit or the like. However, the output of the adaptive array and the re-modulated data are Can be regarded as data having the same content from the beginning, and the same effect can be obtained by inputting the output data of the adaptive array to an arithmetic unit or the like.

Further, in each of the above-described embodiments, an example has been described in which the receiving system is realized as a hardware configuration in which interference cancellers are connected in a plurality of stages. However, these receiving systems are generally implemented in software by a digital signal processor (DSP). It can also be realized with.

The embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

[0324]

As described above, since the present invention is configured to calculate the received response vector from a plurality of response vectors, it is possible to calculate the response vector with high accuracy, and it is possible to calculate the response vector with high accuracy. Communication quality in a wireless communication system can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram showing a configuration of a wireless device (radio base station) 1000 of a PDMA base station to which the present invention is applied.

FIG. 2 is a flowchart illustrating an outline of an operation of a wireless device (wireless base station) 1000;

FIG. 3 is a conceptual diagram for explaining a response vector estimation principle which is a premise of response vector estimation according to the present invention.

FIG. 4 is a conceptual diagram for explaining the estimation principle of response vector estimation according to the present invention.

FIG. 5 is a flowchart showing the operation of the present invention.

FIG. 6 is a block diagram of a receiving system of a PDMA base station according to the present invention.

FIG. 7 is a block diagram illustrating a configuration of the arithmetic device illustrated in FIG. 6;

FIG. 8 is a block diagram of a receiving system of a PDMA base station according to Embodiment 1 of the present invention.

FIG. 9 is a block diagram illustrating a configuration of an interference removing unit illustrated in FIG. 8;

FIG. 10 is a block diagram illustrating a configuration of the arithmetic device illustrated in FIG. 8;

FIG. 11 is a block diagram of a receiving system of a PDMA base station according to Embodiment 2 of the present invention.

FIG. 12 is a block diagram illustrating a configuration of the arithmetic device illustrated in FIG. 11;

FIG. 13 is a block diagram of a receiving system of a PDMA base station according to Embodiment 3 of the present invention.

FIG. 14 is a block diagram illustrating a configuration of an interference removing unit illustrated in FIG. 13;

FIG. 15 is a block diagram of a receiving system of a PDMA base station according to Embodiment 4 of the present invention.

FIG. 16 is a block diagram of a receiving system of a PDMA base station according to Embodiment 5 of the present invention.

FIG. 17 is a block diagram of a receiving system of a PDMA base station according to Embodiment 6 of the present invention.

FIG. 18 is a block diagram of a PDMA base station receiving system according to a seventh embodiment of the present invention.

FIG. 19 is a PD according to Embodiments 8 and 9 of the present invention.
It is a block diagram of the receiving system of the base station for MA.

FIG. 20 is a block diagram showing a configuration of an interference canceller of a receiving system of a PDMA base station according to Embodiment 8 of the present invention.

FIG. 21 is a block diagram showing a configuration of an interference removing unit of a receiving system of a PDMA base station according to Embodiment 9 of the present invention.

FIG. 22 is a block diagram of a receiving system of a CDMA base station according to Embodiment 10 of the present invention.

FIG. 23 is a block diagram illustrating a configuration of an interference removing unit illustrated in FIG. 16;

FIG. 24 is a block diagram showing a configuration of the arithmetic unit shown in FIG.

FIG. 25 is a block diagram showing a configuration of an interference canceller of a receiving system of a CDMA base station according to Embodiment 11 of the present invention.

FIG. 26 is a block diagram showing a configuration of an adaptive array.

FIG. 27 is a channel arrangement diagram of user signals in each of the FDMA, TDMA, and PDMA communication systems.

FIG. 28 is a block diagram showing a conventional receiving system of a PDMA base station.

FIG. 29 is a schematic block diagram illustrating a configuration of an adaptive array wireless base station.

FIG. 30 is a schematic diagram showing a frame configuration of a radio signal of a mobile phone.

FIG. 31 is a schematic diagram illustrating transmission and reception of a radio signal between an adaptive array radio base station and a user.

[Explanation of symbols]

3 to 6 antennas, 7 frequency conversion circuit, 8 A / D converter, 101, 102, 10L, 101 ', 102',
10L 'arithmetic unit, 176 weight vector calculator, 181 to 184 input ports, IC interference removal unit,
DM demodulator, RM remodulator, ED error detector, P
E parameter estimator, MP multiplier, AD adder, A
ND AND gate, GA, GB, GC, GD, GE,
GF, GG, GH Gate part.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04Q 7/36 H04J 15/00 7/38 H04B 7/26 105D H04B 1/707 109A H04J 15/00 H04J 13 / 00 D (72) Hirotaka Koike 2-5-5 Keihanhondori, Moriguchi City, Osaka Prefecture Inside Sanyo Electric Co., Ltd. (72) Inventor Masashi Iwami 2-5-5 Keihanhondori, Moriguchi City, Osaka Prefecture Sanyo Electric Co., Ltd. (72) Inventor Norio Higashida 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Software Co., Ltd. F-term (reference) 5J021 AA05 AA06 CA06 DB02 DB03 DB04 EA04 FA14 FA15 FA16 FA17 FA20 FA26 FA29 FA30 FA31 FA32 GA02 GA08 HA05 HA10 5K022 EE02 EE32 EE35 FF00 5K059 CC02 CC03 CC04 DD32 DD33 DD35 EE02 5K067 AA03 AA11 BB02 CC01 CC10 CC24 EE02 EE10 EE22 EE23 GG01 GG11 KK02 KK03

Claims (5)

[Claims] 1. A wireless receiving system capable of receiving signals from a plurality of users using a plurality of antennas, a signal processing means for performing predetermined signal processing on signals received by the plurality of antennas, A plurality of first signal extracting means for extracting signal components respectively corresponding to the plurality of users based on a signal output from the signal processing means; and a first signal extracting means for extracting a signal component from the signal processing means.
Estimating a plurality of reception response vectors from slots of a propagation path from a specific terminal based on the signal components extracted by the signal extraction means, and using the plurality of reception response vectors, a response vector used for a replica signal operation. Estimating means for calculating a signal and estimating each parameter information; and first calculating means for subtracting a replica signal created based on parameters obtained by the estimating means from a signal output from the signal processing means. And a wireless receiving system. 2. A plurality of first error determination means for determining whether or not signal components corresponding to a plurality of users extracted by the first signal extraction means each include a demodulation error, and the signal processing means Subtracts the extracted signal component determined to contain no demodulation error by the first error determination unit from the signal output from the replica signal created based on the parameters obtained by the estimation unit. And a first calculating means for performing the calculation.
The wireless receiving system according to claim 1. 3. A method according to claim 1, wherein the first error determining means extracts a plurality of signal components corresponding to the users determined to include the demodulation error based on the signal output from the first calculating means. A plurality of second estimating means for estimating parameter information relating to a relationship between a signal output from the first calculating means and a signal component extracted by the second signal extracting means; 2. The apparatus according to claim 1, further comprising a plurality of second error determination means for determining whether each of the signal components extracted by the second signal extraction means includes a demodulation error.
Or the wireless reception system according to 2. 4. A signal output from the signal processing means, which is extracted by the first and second signal extracting means determined to contain no demodulation error by the first and second error determining means. 4. The radio receiving system according to claim 3, further comprising a second calculating unit that subtracts a signal component in consideration of the corresponding parameter information. 5. A signal component extracted from the signal output from the first calculating means and extracted by the second signal extracting means determined not to include a demodulation error by the second error determining means, 4. The wireless receiving system according to claim 3, further comprising a third calculating unit that performs subtraction in consideration of the corresponding parameter information.