KR20020085608A - Channel estimator using multi-channel - Google Patents

Abstract

PURPOSE: An apparatus for estimating channels using a multichannel is provided to execute channel phase estimation according to the ratio of channel signals using an MRC(Maximum Ratio Combine). CONSTITUTION: An apparatus for estimating channels using a multichannel is comprised of a control channel despreader(201), a data channel despreader(202), a control channel phase estimation unit(203), a data channel phase estimation unit(204), an adder(205), an averager(206), multipliers(207,208), real number units(209,210), the first hard decision(211), and the second hard decision(212). The control channel despreader(201) despreads a received control channel signal. The data channel despreader(202) despreads a received data channel signal. The control channel phase estimation unit(203) takes the absolute value for the despread control channel signal, multiplies the absolute value by its own channel signal, and estimates a control channel phase. The data channel phase estimation unit(204) takes the absolute value for the despread data channel signal, multiplies the absolute value by its own channel signal, and estimates a data channel phase. The adder(205) adds the estimated data channel phase value to the estimated control channel phase value. The averager(206) averages the output channel phase values of the adder(205) and detects a channel phase estimation value. The multipliers(207,208) respectively multiply the restored channel signals by the channel phase estimation value for channel compensation. The real number units(209,210) detect the real parts of the output channel signals of the multipliers(207,208) and output demodulated channel signals. The first hard decision(211) obtains a temporary decision value from the real value of the control channel signal and transfers a pilot pattern to the control channel phase estimation unit(203). The second hard decision(212) obtains a temporary decision value from the real value of the data channel signal and multiplies it by the estimated data channel phase value.

Description

Channel estimator using multi-channel}

The present invention provides a demodulator for a reverse link channel signal of a mobile communication system, and in particular, a channel estimating apparatus using multi-channel for multiplying a data channel power and a control channel power when performing multi-channel estimation. It is about.

Channel compensation in a wideband code division multiple access (e.g., W-CDMA) demodulator extracts the real and imaginary components separately by estimating the phase of the received signal and is mainly used for coherent reception. . At this time, in order to estimate the phase, if a signal of a code promised in advance to the received signal, that is, a signal known to the receiver, comes, the receiver can look at the signal and extract phase information.

In this coherent mode, there is a pilot signal, and the receiver uses this pilot signal to estimate the channel through which the actual transmission signal has passed, recovers the signal distorted by this channel to the original signal, and adjusts the signal to match the phase of the signal. It will be demodulated.

In the uplink of a wideband code division multiple access (W-CDMA), a pilot symbol exists for phase information extraction. For example, if a transmission signal sends +1 to I and +1 to Q as pilot symbols, The receiving side is used to demodulate the data signal by looking at the I and Q components and knowing how much the I and Q signals rotate in the complex plane.

1 is a diagram illustrating a structure of a dedicated physical data channel and a dedicated physical control channel as a signal configuration of a reverse link.

Dedicated Physical Channel (DPCH) consists of Dedicated Physical Data Channel (DPDCH), which is a data channel, and Dedicated Physical Control Channel (DPCCH), which is a control channel. One radio frame having = 10 ms is composed of 15 time slots (Slot # 0 to Slot # 14), and one time slot is composed of 2560 chips. DPDCH's 2650 chip consists of a pilot, a transport format combination indicator (TFCI), feedback information (FBI), and transmit power control (TPC).

When using the above-described pilot signal as channel compensation, if one symbol (bit in FIG. 1) is used, distortion occurs in the channel compensation due to insufficient signal-to-noise ratio. Therefore, the pilot signal is accumulated to minimize the noise component in order to increase the signal-to-noise ratio. do. A channel compensation device for minimizing such noise is shown in FIG. 2.

FIG. 2 is a block diagram illustrating a conventional channel compensator using multi-channels. Referring to FIG. 2, DPCCH and DPDCH despreaders 101 and 102 for despreading a control channel signal and a data channel signal of a received signal are shown. A first multiplier (103) multiplying the despread control channel signal by a temporary estimate, an average (104) averaging the pilot multiplied by the first multiplier, and an output value of the output of the average (104). The second and third multipliers 105 and 106 and the output values of the second and third multipliers 105 and 106 which channel compensate the control channel and the data channel by using the real part 107 and 108 It is configured to obtain demodulated DPDCH and DPCCH values by receiving real component.

From this configuration, conventionally, the pilot of the control channel signal demodulated in the DPCCH despreader 101 is multiplied by an arbitrary estimate in the first multiplier 103, and then averaged to the averager 104 to obtain a channel compensation value.

The channel compensation value compensates the DPCCH signal and the DPDCH signal despread in the third and fourth multipliers 105 and 106 as channel phase estimates, and allows the real part 107 and 108 to detect only real components. Therefore, demodulated DPDCH signals and DPCCH signals are output.

However, to compensate for the lack of energy of the pilot signal, other symbols of the control channel (DPCCH) signal are used, but since the symbol values are not known, only the pilot estimates are obtained from the hard decision (109). By multiplying by the multiplier 103, the remaining sections of the control channel DPCCH are also used for channel estimation using the remaining symbols (except the pilot symbols).

However, as the data rate of the DPDCH signal changes, the data channel (DPDCH) signal has a high signal strength when the data rate is high and a weak signal strength when the data rate is low.

Since the data rate can be known by the receiver only after receiving one frame of TFCI, the data rate is not known when it is not received.

Channel compensation should be combined in proportion to the channel estimates of the data channel (DPDCH) signal and the estimate strength of the control channel (DPCCH) signal, which conventionally does not determine the ratio of combining the estimates of the DPCCH signal and the estimates of the DPDCH. Can not be used for channel phase estimation. That is, when the channel compensation value is used as the data channel, it is difficult to determine the ratio with the control channel as the spreading factor of the data channel changes, so that only the control channel should be used.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and by taking the absolute value of the signal strength of the data channel and the signal strength of the control channel using the maximum transmission rate combination (MRC), It is an object of the present invention to provide a channel estimating apparatus using multi-channels in which channel phase estimation is performed according to a channel signal ratio by multiplying and combining their signal strengths.

1 is a data format diagram illustrating a structure of a reverse dedicated physical channel.

2 is a block diagram illustrating a channel estimating apparatus using a conventional control channel.

3 is a block diagram illustrating a channel estimating apparatus using multi-channels according to an exemplary embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

101,201 ... Control Channel Despreader 102,202 ... Control Channel Despreader

103,105,106,203b, 204b, 207,208 ... Multipliers

104,206 ... Average107,108,209,210

109,211,212 ... hard decision

203 ... control channel phase estimation means

204 ... data channel phase estimation means

203a, 204a ... Absolute value detector

In order to achieve the above object, the channel estimation apparatus using a multi-channel according to the present invention,

Control channel phase estimating means for estimating the channel phase by multiplying the control channel signal despread by the control channel despreader with the current weight of its own channel signal;

Data channel phase estimating means for estimating the channel phase by multiplying the data channel signal despread by the data channel despreader by the current channel signal strength;

Adding means for adding the estimated data channel phase estimate to a control channel phase estimate;

An averager for averaging the output of said adding means to obtain a channel phase estimate;

Multiplication means for multiplying the output channel phase estimate of the averager by multiplying the reconstructed data channel signal and the control channel signal respectively;

And a real part which detects the real component of the channel signal output from the multiplication means and outputs the demodulated data channel signal and the control channel signal, respectively.

Preferably, a first hard decision for multiplying a pilot pattern having a temporary decision value fed back the real component of the control channel signal by a phase value estimated by the control channel phase estimating means and a real component of the data channel signal And a second hard decision multiplying the channel phase value estimated by the data channel weight estimating means.

Preferably, the weight detection means includes an absolute value detector and a multiplier, respectively, to take an absolute value of the channel signal and multiply the absolute value by its own channel signal.

Hereinafter, with reference to the accompanying drawings as follows.

2 is a block diagram illustrating a channel estimating apparatus using multi-channels according to an exemplary embodiment of the present invention.

Referring to FIG. 2, a control channel despreader 201 despreads a reception control channel signal, a data channel despreader 202 despreading a received data channel signal, and an absolute value of the despread control channel signal. Control channel phase estimating means (203) for estimating a control channel phase by taking an absolute value and multiplying the absolute channel by its own channel signal, and estimating the data channel phase by taking an absolute value of the despread data channel signal and multiplying the absolute value by its own channel signal. A data channel phase estimation means 204, an adder 205 for adding a data channel phase value to the estimated control channel phase value, an averager 206 for averaging the output channel phase value of the adder and detecting a channel phase estimate value; First and second multipliers 207 and 208 for multiplying the channel phase estimate by the reconstructed data channel signal and the control channel signal to perform channel compensation; A real part 209 (210) for detecting the real component of the output channel signal of the second multiplier and outputting the demodulated control channel signal and the control channel signal, and obtaining a temporary decision value from the real value of the control channel signal. A first hard decision (211) for transmitting to the control channel phase estimating means (203) and a real value component of the data channel signal to obtain a temporary decision value and multiply the estimated phase value by the data channel estimating means. It is a configuration including the two hard decision 212.

The control channel phase estimating means comprises an absolute value detector 203a which takes an absolute value in the control channel signal, and a third multiplier 203b which multiplies the absolute value by its own signal and estimates the channel phase by combining with a pilot pattern. ,

The data channel phase estimating means 204 comprises an absolute value detector 204a which takes an absolute value in the data channel signal, and a fourth multiplier 204b that multiplies the absolute value by its own signal and the output value of the second hard decision. do.

Referring to the accompanying drawings, a channel compensation device using a multi-channel according to an embodiment of the present invention configured as described above is as follows.

First, the control channel (DPCCH) signal received at the mobile station on the reverse link is despread by the control channel despreader 201 and the received data channel (DPDCH) signal is despread by the data channel despreader 202. .

At this time, the control channel phase estimating means 203 is composed of an absolute value detector 203a and a third multiplier 203b, and the absolute value detector 203a is despread by the control channel despreader 201. The third multiplier 203b multiplies the despreaded control channel signal by an absolute value to combine and estimate the channel phase.

The data channel phase estimating means 204 is composed of an absolute value detector 204a and a fourth multiplier 204b, and the absolute value detector 204a is despread by the data channel despreader 202. The fourth multiplier 204b estimates the channel phase by multiplying the despread data channel signal by the absolute value and combining the absolute values.

The channel phase means (203, 204) multiplies the data channel (DPDCH) signal and the control channel (DPCCH) by multiplying the current signal strength by its weight, and since the signal strength is an absolute value, the signal absolute value is multiplied by its channel to combine. Estimate the channel phase.

The adder 205 is added to the channel estimate estimated by the control channel phase estimating means 204 and the data channel phase value, and then averaged by the averager 206 to output the channel phase estimate according to the channel signal ratio.

The channel phase estimate of the averager 206 is multiplied by the control channel signal reconstructed by the first multiplier 207 to be the control channel compensation, and is multiplied by the data channel signal reconstructed by the second multiplier 208 to compensate for the data channel. This is done for each.

The control channel signal output from the first multiplier 207 is output as a demodulated control channel signal by detecting the real component in the first real part 209, and the data channel signal output from the second multiplier 208 is output to the second. The real component is detected by the real unit 210 and output as a demodulated data channel signal.

The real component of the control channel signal output from the first real part is determined by the first hard decision 211 using a temporary decision estimate of data to determine a pilot pattern and using the remaining symbols (except the pilot). The third multiplier 203b of the phase estimating means 203 is multiplied by the control channel and multiplied by an absolute value, and the remaining sections of the control channel to be used are also used for channel estimation.

The real component of the data channel signal output from the second real part is transferred from the second hard decision 212 to the fourth multiplier 204b, and multiplied by the value of the data channel signal in the fourth multiplier 204b. In addition, a channel phase estimate with weights is generated by multiplying by an absolute value.

As described above, by taking the absolute value of the data channel signal and the control channel signal according to the present invention, the signal strength is obtained, and the channel absolute value can be estimated by multiplying and combining the signal absolute value with its own channel signal, thereby controlling the data channel and control. By using the estimate of the channel to determine the ratio to combine has the effect of more accurate channel estimation.

Claims (3)

Control channel phase estimating means for estimating the channel phase by multiplying the control channel signal despread by the control channel despreader with the current weight of its own channel signal; Data channel phase estimating means for estimating the channel phase by multiplying the data channel signal despread by the data channel despreader by the current channel signal strength; Adding means for adding the estimated data channel phase estimate to a control channel phase estimate; An averager for averaging the output of said adding means to obtain a channel phase estimate; Multiplication means for multiplying the output channel phase estimate of the averager by multiplying the reconstructed data channel signal and the control channel signal respectively; And a real part for detecting a real component of the channel signal output from the multiplication means and outputting a demodulated data channel signal and a control channel signal, respectively. The method of claim 1, A first hard decision that multiplies a phase value estimated by the control channel phase estimating means by a pilot pattern, which is a temporary decision value fed back to the real component of the control channel signal, and a data channel weight by using the real component of the data channel signal; And a second hard decision multiplying the channel phase value estimated by the estimating means. The method of claim 1, And the weight detection means includes an absolute value detector and a multiplier to take an absolute value of the channel signal and to multiply the absolute value by its own channel signal.