KR100681760B1 - Receiver with plurality of equalizers - Google Patents

Abstract

A receiver having plural equalizers is provided to effectively cope with various multipath fading phenomenona by training equalizers in real time by using the pilot channel information transmitted from a base station. A chip level equalizer(310) in a receiver comprises an iterative equalizer(311), a block equalizer(312), the first and second metric production parts(314,315), and a controller(317). The iterative equalizer(311) obtains a filter tap coefficient through iterative calculation using the pilot channel information received from a base station, and then compensates a signal, inputted to the chip level equalizer(310), by using the calculated filter tap coefficient. The block equalizer(312) obtains a filter tap coefficient through non-iterative calculation using the pilot channel information, and then compensates the inputted signal by using the calculated filter tap coefficient. The metric production parts(314,315) calculate a metric value, which indicates a wireless channel state, by using a chip level signal outputted from the iterative equalizer(311) or the block equalizer(312). The controller(317) compares the metric value with more than one reference value and controls active or inactive state of the block equalizer(312).

Description

Receiver with multiple equalizers {RECEIVER WITH PLURALITY OF EQUALIZERS}

1 is a diagram illustrating a configuration of a mobile communication system using a general High Speed Physical Downlink Shared Channel (HSPDS) method.

Figure 2 is a simplified diagram showing the configuration of a receiver according to an embodiment of the present invention.

3 is an operational state diagram of a receiver according to an embodiment of the present invention.

<Description of Symbols for Main Parts of Drawings>

100: base station

200: wireless channel

300: mobile terminal

301: receiving antenna

302: receiving circuit

303: signal processing unit

305: Decoder

310: Chip Level Equalizer

311: iterative equalizer

312 block equalizer

313: Reference signal provider

314: First metric calculation unit

315: second metric calculation unit

316: switching unit

317: control unit

318: multi-code processing unit

The present invention relates to a mobile communication receiver, and more particularly, to a mobile communication receiver having an equalizer.

1 is a diagram illustrating a configuration of a mobile communication system using a general high speed physical downlink shared channel (HSPDS) method.

As shown in FIG. 1, a general CDMA mobile communication system includes a base station 100, a wireless channel 200, and a mobile terminal 300. The HSPDS type mobile communication system is a system for transmitting high speed data from the base station 100 to the mobile terminal 300.

The base station 100 allocates different orthogonal codes to a plurality of channels, synchronizes and sums up a plurality of channel signals assigned to the orthogonal codes and radiates them through the antenna 107.

In this case, in order to ensure that the summed channel signals are efficiently transmitted in a wireless space and also to ensure proper reception sensitivity in the mobile terminal 300, modulation, frequency conversion and Power amplification 106 is preceded.

The channel transmitted from the base station 100 to the mobile terminal 300 includes an HSPDS channel 101 for transmitting high speed data, a pilot channel 102 for transmitting a pilot signal, and a mobile terminal 300. Control channel 103 including P-CCPCH channel, SCCH channel, DPCH channel, etc. for transmitting control information, system information, etc., OCNS channel 104 for equivalently displaying a channel for transmitting voice signals, etc. There is this.

A signal composed of a plurality of physical layer channels radiated from the base station 100 generates a path loss 201 and a multipath fading phenomenon 202 in the process of being transmitted to the mobile terminal 300, thereby decreasing its strength. And become distorted. The path loss 201 is caused by distance and shadowed area, and the multipath fading phenomenon 202 is a plurality of moving paths and mobile terminals formed by being reflected by a plurality of reflectors (for example, buildings, mountains, trees, etc.). The composite is formed by the Doppler effect generated by the movement of the 300.

In addition, the signal transmitted from the base station 100 is the interference signal 203, various noise sources 203 and unwanted signals generated from the interference frequency source 203 transmitted from the other base station is added to the mobile terminal ( 300).

The mobile terminal 300 receives the channel signal radiated from the base station 100 through the antenna 301, performs demodulation in the baseband unit 303 after performing a low noise amplification and frequency conversion process 302.

As described above, the channel signal demodulated by the baseband unit 303 has a multipath fading phenomenon on the transmission path, and an unwanted noise and interference signal are summed and remain in a severely distorted state.

Here, the multipath fading phenomenon occurring in the radio space is mainly formed by the multipath formed by the various reflectors and the Doppler effect caused by the movement of the mobile terminal 300. The conventional rake receiver 304 has a path searcher function. The multipath can be distinguished within the resolution range.

Therefore, the rake receiver 304 allocates an independent receiver called a finger to a multipath separated by a path searcher function, and implements a path diversity function that detects a signal while tracking each path individually, rather than a general receiver. Excellent performance.

As shown in FIG. 1, a plurality of channel signals that are synchronized and summed at the base station 100 may be distinguished only when orthogonality is ensured between codes. However, since the orthogonality between the codes is broken by multipath fading occurring on the wireless transmission path, it is difficult to distinguish between the various code channels at the receiving end of the mobile terminal 300, so that other channels act as interference signals that prevent the detection of desired channels. Multiple User Interference (MUI) or Multiple Access Interference (MAI) effects are generated.

This phenomenon occurs when different orthogonal code channels are simultaneously assigned to each user for simultaneous service to a plurality of users, or when a plurality of orthogonal code channels are simultaneously assigned to one user for high speed data transmission. This may occur when the orthogonal code channels are simultaneously allocated in a complex form.

In particular, when changing the modulation scheme (QPSK, 16QAM) according to the radio channel state in order to transmit high-speed data, the MAI phenomenon may be noticeable. The main factor that destroys the orthogonality of multiple orthogonal channels overlapping in synchronization is that when multipaths formed by a plurality of reflectors in a radio transmission path overlap each other, they overlap at random intervals instead of integer multiples of the orthogonal channel period. to be.

Conventional rake receivers have a function of distinguishing multiple paths, but this is only to distinguish the starting point of each multipath, but there is a limit that cannot remove signals from other paths overlapping at random intervals. Therefore, the rake receiver is not suitable to cope with the MAI generated by using a plurality of orthogonal code channels at the same time.

In order to solve this problem, attempts have recently been made to use an equalizer instead of a rake receiver. This is because using the equalizer, the orthogonality between the various code channels destroyed in the radio channel can be restored to some degree, which is better than that of the rake receiver.

Conventional equalizers are mainly used to reduce inter symbol interference (ISI), which is an interference effect between transmission symbols, and has an effect when a terminal device is fixed or moves at a low speed.

However, as shown in FIG. 1, when multiple orthogonal code channels are simultaneously used to transmit high speed data, the equalizer has not been generally used when the mobile terminal 300 moves at high speed.

The equalizer is used to recover orthogonality between various code channels by appropriately coping with various multipath fading phenomena occurring in an indoor environment in which the mobile terminal 300 is almost stationary, or an outdoor environment in which a user moves at a medium speed or high speed while walking or moving in a vehicle. Properly trained regularly or in real time.

To this end, an appropriate training signal must be received from the base station but current mobile communication systems do not transmit a separate signal for training the equalizer. Therefore, it is not effective to use the equalizer to achieve the desired performance by reducing the MAI effect caused by the fast multipath fading phenomenon to date.

Accordingly, an object of the present invention is to provide a receiver having a plurality of equalizers capable of minimizing an MAI effect.

In addition, another object of the present invention to provide a receiver having a plurality of equalizers that can improve the ability to cope with various multipath fading phenomenon by training the equalizer in real time using the pilot channel information transmitted from the base station. It is.

In addition, another object of the present invention is to provide a receiver having a plurality of equalizers by which a mobile terminal can secure excellent reception performance in indoor and outdoor environments by adopting a dual structure to improve MAI performance.

In addition, another object of the present invention is to control the driving of some or all of the plurality of equalizers provided in accordance with the change in the wireless environment to minimize the power consumption of the mobile terminal, and also to improve the performance of the wireless environment changes It is to provide a receiver having a plurality of equalizers that can be maintained.

Other objects of the present invention will become more apparent through the preferred embodiments described below.

According to an aspect of the present invention for achieving the above object, there is provided a receiver having a chip level equalizer and / or a chip level equalizer.

A chip level equalizer included in a receiver according to an exemplary embodiment of the present invention calculates filter tap coefficients by an iterative operation using pilot channel information received from a base station, and uses the filter tap coefficients to calculate the filter tap coefficients. A repeating equalizer for correcting a signal input to the equalizer; A block equalizer for calculating filter tap coefficients by a non-repetitive operation using the pilot channel information and correcting a signal input to the chip level equalizer using the filter tap coefficients; A metric calculator for calculating a metric value indicating a wireless channel state by using a chip level signal output from the repeating equalizer or the block equalizer; And a controller for controlling an active or inactive state of the block equalizer by comparing the metric value with at least one predetermined reference value, and controlling which output of the equalizer is used.

The iterative equalizer may use an adaptive algorithm to calculate the filter tap coefficients. Here, the adaptive algorithm may be at least one of an LMS algorithm, an RLS algorithm, an SQ-RLS algorithm, and the like.

 The block equalizer may use an auto-correlation matrix to calculate the filter tap coefficient. Here, the auto-correlation matrix may be at least one of a Levinson recursion algorithm, a Wiener Lattice filter algorithm, a conjugate gradient algorithm, and the like.

The metric calculator may predict a pilot symbol from the chip level signal output from the iterative equalizer, and calculate and output an average value of the difference between the predicted pilot symbol and a preset pilot reference signal as the metric value. Here, the metric value may be calculated based on one frame.

According to another aspect of the present invention for achieving the above object, there is provided a method for controlling an equalizer of a chip level equalizer and / or a recording medium on which a program for executing the method is recorded.

The equalizer control method in the chip level equalizer included in the receiver according to an embodiment of the present invention, in the iterative equalizer to calculate the filter tap coefficient by iterative calculation using the pilot channel information received from the base station (A) receiving a first metric value obtained by using the output chip level signal from a metric calculator; (B) activating a block equalizer that calculates a filter tap coefficient by a non-repetitive operation using the pilot channel information when the first metric value satisfies a first predetermined criterion; And (c) deactivating the block equalizer if the second metric value obtained using the chip level signal output after the step (b) from the repeat equalizer satisfies a second predetermined criterion. Can be.

When the block equalizer is activated, the output of the block equalizer may be used in the receiver.

The iterative equalizer may use an adaptive algorithm to calculate the filter tap coefficients. Here, the adaptive algorithm may be at least one of an LMS algorithm, an RLS algorithm, an SQ-RLS algorithm, and the like.

 The block equalizer may use an auto-correlation matrix to calculate the filter tap coefficient. Here, the auto-correlation matrix may be at least one of a Levinson recursion algorithm, a Wiener Lattice filter algorithm, a conjugate gradient algorithm, and the like.

The first metric value and the second metric value are calculated by a metric calculator, wherein the metric calculator predicts a pilot symbol from a chip level signal output from the iterative equalizer, and estimates the pilot symbol and the preset pilot symbol. The average value of the difference between the reference signals may be calculated and output as the metric value. Here, the metric value may be calculated based on one frame.

The present invention includes WCDMA for changing the modulation scheme and the number of channel codes used to transmit high-speed data through a multipath fading channel whose state changes in real time due to the movement of the mobile terminal 300. In a mobile communication system such as a system, a plurality of equalizers may be trained using a pilot symbol transmitted from a base station 100 in real time, and a plurality of equalizations may be provided. The present invention relates to a receiver having a plurality of equalizers, in which the groups are combined in a parallel structure and efficiently driven to have a superior performance than a conventional rake receiver.

Hereinafter, a receiver having a plurality of equalizers according to the present invention will be described in detail with reference to the accompanying drawings. However, the description will be given on the assumption that there are two equalizers provided in the receiver, but three or more equalizers may be combined and operated in series / parallel, and only a specific equalizer may be selectively activated to obtain a desired performance. It will be self explanatory through explanation.

In addition, in the following description of the present invention with reference to the accompanying drawings, the same or corresponding components will be given the same reference numerals and redundant description thereof will be omitted.

2 is a diagram briefly showing a configuration of a receiver according to an exemplary embodiment of the present invention. That is, FIG. 2 shows an iterative equalizer 311 and a block equalizer 312 in parallel to restore orthogonality between different code channels destroyed by various radio channel environments to obtain excellent reception performance. The figure shows a chip level equalizer 310 having a combined dual structure. The chip level equalizer 310 according to the present invention trains each of the equalizers 311 and 312 using pilot channel information which is always received in real time from the base station 100. Determine the action.

2, a receiver according to the present invention includes a receiving antenna 301, a receiving circuit unit 302, a signal processing unit 303, a chip level equalizer 310, and a decoder 305.

The signal received through the receiving antenna 301 of the mobile terminal 300 is low noise amplified and frequency converted by the receiving circuit 302. Receive circuitry 302 may include a low pass noise amplifier (LNA) and a frequency converter.

The low noise amplified and frequency-converted signal by the receiving circuit unit 302 is input to the signal processing unit 303 to perform signal processing such as demodulation, analog-to-digital conversion, matched filtering, and the like. And then input to the chip level equalizer 310.

The chip level equalizer 310 includes an iterative equalizer 311, a block equalizer 312, a reference signal provider 313, and a first metric calculator 314. ), A second metric calculator 315, a controller 317, a switching unit 316, and a multicode processor 318.

In general, when the base station 100 transmits a signal, desired information is represented by a data symbol. However, in a CDMA-based mobile communication system, a chip stream obtained by multiplying a data symbol by a predetermined orthogonal code for multiple access and reception sensitivity, etc. transmits a chip stream through a wireless space. Therefore, when the receiver recovers the signal received by the equalizer, the signal is restored in the chip unit or the data symbol unit. Of these, the chip level equalizer 310 according to the present invention restores the signal in units of chips.

The signal input from the signal processor 303 is branched and input to the repeat equalizer 311 and the block equalizer 312, respectively.

The iterative equalizer 311 uses a pilot symbol composed of 256 pilot chips on a pilot channel received in real time from the base station 100 as a training signal. The training of the repetitive equalizer 311 predicts an average pilot symbol in one frame and compares the reference signal 1 + j input from the reference signal provider 313 to compensate for the difference (error) between the two signals. This is done adaptively by minimizing through iterative computation of times. That is, since the reference signal is generated for every 256 pilot chips, the same filter tap coefficient is used on the assumption that the wireless channel does not change for 256 chips, and then the filter tap coefficient is obtained using the reference signal again. As such, the training is performed by using the obtained tap coefficient values for each 256 chip.

As described above, the iterative equalizer 311 is an arbitrary equalizer that operates in an iterative manner to compare the reference signal with the predicted signal in order to minimize the difference (error) between the reference signal and the predicted signal. Can be. The iterative equalizer 311 may apply any adaptive algorithm, such as, for example, an LMS algorithm, an RLS algorithm, an SQ-RLS algorithm, etc. to obtain a filter tap coefficient.

The iterative equalizer 311 is robust to multipath fading that occurs in a wireless channel by adaptive training. However, since the iterative equalizer 311 can minimize the desired error only after sufficient iteration is performed, it does not show good performance in a rapidly changing wireless channel. However, since the repeating equalizer 311 uses the input data as it is without further processing, the mobile terminal 300 may exhibit excellent performance in an indoor environment in which the mobile terminal 300 is stationary or slightly moved.

The block equalizer 312 uses a pilot symbol composed of 256 pilot chips on a pilot channel received in real time from the base station 100 in the same manner as the repeat equalizer 311 as a training signal. Also, the block equalizer 312 compares the average pilot symbol with the reference signal 1 + j input from the reference signal provider 313, but unlike the repeat equalizer 311, the block equalizer 312 adaptively compares the difference between the two signals. The method of minimizing the difference (error) between two signals through a single calculation process without minimizing by repeating through the same method is applied. Since the block equalizer 312 obtains the filter tap coefficients using the pilot channel and the method of applying the same, the description thereof will be omitted.

As described above, the block equalizer 312 uses a matrix inversion or a similar method, rather than an iterative method, to minimize the difference (error) between the reference signal and the predicted signal. Can be operated. The block equalizer 312 may apply an auto-correlation matrix such as a Levinson recursion algorithm, a Wiener Lattice filter algorithm, a conjugate gradient algorithm, and the like, to obtain filter tap coefficients.

Although the block equalizer 312 has an advantage of showing good performance in a rapidly changing wireless channel, reliable data is absolutely necessary to obtain a desired value through a single calculation, and input data is required to obtain reliable data. There is a disadvantage that additional processing of is required. However, the additional processing of the input data is adversely affected in the indoor environment in which the mobile terminal 300 is in a stationary state or slightly moved.

As described above, in order for the chip level equalizer 310 according to the present invention to exhibit excellent reception performance in all the wireless channel environments in the indoor and outdoor where the mobile terminal 300 operates, the repeating equalizer 311 in the indoor wireless channel environment. ) And drive the block equalizer 312 in an outdoor wireless channel environment to complement each other's performance.

Accordingly, the chip level equalizer 310 according to the present invention allows the repeating equalizer 311 and the block equalizer 312 to be coupled in parallel, and the controller 317 corresponds to the equalizers as shown in FIG. 2. One or more of 311 and 312 are implemented to control to be active or inactive depending on the wireless channel environment.

To this end, the metric calculators 314 and 315 are coupled to the output terminals of the equalizers 311 and 312, respectively, and the metric calculators 314 and 315 are each chip level passed through the equalizers 311 and 312. A metric value representing a change in the radio channel environment in the signal is calculated.

The pilot chips in the pilot channel transmitted in a quadrature phase shift keying (QPSK) scheme in real time from the base station 100 are all 1 in size and are repeated every 256 cycles. In addition, the chips constituting the other channel have a period of 256, but the size varies according to the data symbol value, and the code multiplied by each symbol is orthogonal to the respective code and pilot code. However, the orthogonality between codes is broken by multipath fading while being transmitted through a wireless channel, so it is not easy to distinguish each channel at a receiving end.

However, applying this property to the pilot channel can provide a good clue as to how much orthogonality between the destroyed channels in the wireless channel is restored by the equalizer. Therefore, the pilot symbol is predicted from the sum signal of the orthogonal code channels reconstructed by the iterative equalizer 311 and the block equalizer 312 and compared with the known pilot reference signal 1 + j to obtain the average value of the difference. Can be used as a metric value.

As described above, the two metrics 314 and 315 calculated by the output terminals of the repeating equalizer 311 and the block equalizer 312 are compared with each other or compared with a preset absolute reference value. In a channel environment, it is possible to determine which equalizer 311 or 312 performs better.

Of course, it would be ideal to drive two equalizers 311 and 312 at the same time to obtain two outputs and then use the outputs of the equalizer 311 or 312 with the better performance of the two.

However, driving two equalizers 311 and 312 all the time is not efficient in view of the power consumption of the mobile terminal 300. Therefore, the equalizer of the two equalizers 311 and 312 is always driven, and the pilot symbol metric calculated by the metric calculation units 314 and 315 provided at the output thereof is compared with the absolute reference value to determine the current radio channel state. The method of determining whether to operate the other equalizer after predicting may be more efficient in terms of power consumption of the mobile terminal.

As such, the controller 317 according to the present invention may determine which equalizer should be activated by comparing the metric inputted by the metric calculators 314 and 315 with the reference value, and also determine whether the equalizer is activated or not. Since the inactivity can be controlled, power consumption of the mobile terminal 300 can be minimized.

In the HSPDS system described as an example in the present specification, the frame length, which is a basic unit for transmitting a signal, is 2ms including 7680 chips, and this time is very short compared to the time when the mobile terminal 300 moves.

Therefore, as described above, while always driving the equalizer with a small amount of calculation, it is necessary to predict the current channel state in units of 2ms and to use this information to determine whether to drive the other equalizer to obtain the optimal reception performance. In terms of power, it is an efficient and optimal way to achieve the desired reception performance.

The metric values calculated by the above-described method are input to the controller 317, and the controller 317 determines whether to activate the repetitive equalizer 311 or the block equalizer 312 with reference to the input metric values. To control.

In addition, when both equalizers 311 and 312 are activated, the controller 317 outputs a path selection signal to the switching unit 316 indicating which output of the equalizer is to be used to output the desired output signal. To be used.

 The signal output from the switching unit 316 is input to the multicode processor 318, and the multicode processor 318 performs scrambling and spreading on the input signal. The signal input by the multicode processor 318 is converted into data symbols carried on each channel, and then summed in series to be input to the decoder 305.

The decoder 305 performs decoding and additional signal processing on the input signal.

3 is an operational state diagram of a receiver according to an embodiment of the present invention.

3 illustrates one of several states in which chip level equalizer 310 may operate. In the state where the chip level equalizer 310 is operable, the iterative EQ only mode 501 in which only the repeat equalizer 311 is activated, the iterative + block in which the repeat equalizer 311 and the block equalizer 312 are simultaneously activated There may be an EQ mode 502. In addition, even when the equalizer having a large amount of calculation is considered, the block EQ only mode in which only the block equalizer 312 is activated may be further present, but the description thereof will be omitted.

In the iterative EQ only mode 501, the repetitive equalizer 311 performs an equalization function with respect to the input signal and simultaneously monitors the wireless channel state. That is, the wireless channel state may be monitored using the metric value calculated by the first metric calculator 314 coupled to the iterative equalizer 311.

If it is determined that the block equalizer 312 is to be activated because the metric value indicating the wireless channel state is larger than a desired reference value (503), the operating state of the chip level equalizer 310 is in the iterative EQ only mode (501). Switch to iterative + block EQ mode 502. That is, the block equalizer 312 is additionally activated.

In the iterative + block EQ mode 502, the output of the block equalizer 312 is selected and delivered to subsequent components. Even in this case, the metric value calculated by the first metric calculator 314 using the output of the repeating equalizer 311 may be used as a value for monitoring the wireless channel state.

If it is determined that the metric value input from the first metric calculator 314 is smaller than another preset reference value and the block equalizer 312 needs to be deactivated (504), the operation of the chip level equalizer 310 is performed. The state switches back from iterative + block EQ mode 502 to iterative EQ only mode 501.

As described above, the chip level equalizer 310 according to the present invention uses a special dual structure in which two equalizers 311 and 312 are connected in parallel to solve the MAI problem of the conventional rake receiver. It can be greatly improved in both environments.

As described above, a receiver having a plurality of equalizers according to the present invention has an effect of minimizing an MAI effect.

In addition, the present invention has an effect of improving the ability to cope with various multipath fading phenomena by training the equalizer in real time using the pilot channel information transmitted from the base station.

In addition, the present invention has the effect that the mobile terminal can secure excellent reception performance in the indoor environment and outdoor environment by adopting a dual structure to improve the MAI performance.

In addition, the present invention can minimize the power consumption of the mobile terminal by controlling some or all of the plurality of equalizers provided in accordance with the change in the wireless environment, and can also maintain excellent performance against changes in the wireless environment There is also.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art to which the present invention pertains without departing from the spirit and scope of the invention as set forth in the claims below It will be appreciated that modifications and variations can be made.

Claims (15)

In the chip level equalizer included in the receiver, A repetitive equalizer for calculating filter tap coefficients by repetitive calculation using pilot channel information received from a base station and correcting a signal input to the chip level equalizer using the filter tap coefficients; A block equalizer for calculating filter tap coefficients by a non-repetitive operation using the pilot channel information and correcting a signal input to the chip level equalizer using the filter tap coefficients; A metric calculator for calculating a metric value indicating a wireless channel state by using a chip level signal output from the repeating equalizer or the block equalizer; And And a controller for controlling an active or inactive state of the block equalizer by comparing the metric value with at least one predetermined reference value and controlling which output of the equalizer is to be used. The method of claim 1, And the iterative equalizer uses an adaptive algorithm to calculate the filter tap coefficients. The method of claim 2, And said adaptive algorithm is at least one of an LMS algorithm, an RLS algorithm, and an SQ-RLS algorithm. The method of claim 1, And the block equalizer uses an auto-correlation matrix to calculate the filter tap coefficients. The method of claim 4, wherein And the auto-correlation matrix is at least one of a Levinson recursion algorithm, a Wiener Lattice filter algorithm, and a conjugate gradient algorithm. The method of claim 1, The metric calculator estimates a pilot symbol from the chip level signal output from the iterative equalizer, and calculates and outputs an average value of the difference between the predicted pilot symbol and a preset pilot reference signal as the metric value. Level equalizer. The method of claim 6, And the metric value is calculated based on one frame. In the equalizing unit control method of the chip level equalizer of claim 1, (A) receiving a first metric value obtained by using a chip level signal output from a repeating equalizer which calculates a filter tap coefficient by an iterative operation using pilot channel information received from a base station (a); (B) activating a block equalizer that calculates a filter tap coefficient by a non-repetitive operation using the pilot channel information when the first metric value satisfies a first predetermined criterion; And And (c) deactivating the block equalizer if the second metric value obtained using the chip level signal output after the step (b) from the iterative equalizer satisfies a second predetermined criterion. Wealth control method. The method of claim 8, If the block equalizer is activated, the output of the block equalizer is used in the receiver. The method of claim 8, And the iterative equalizer uses an adaptive algorithm to calculate the filter tap coefficients. The method of claim 10, And the adaptive algorithm is at least one of an LMS algorithm, an RLS algorithm, and an SQ-RLS algorithm. The method of claim 8, And the block equalizer uses an auto-correlation matrix to calculate the filter tap coefficients. The method of claim 12, And the auto-correlation matrix is at least one of a Levinson recursion algorithm, a Wiener Lattice filter algorithm, and a conjugate gradient algorithm. The method of claim 8, The first metric value and the second metric value are calculated by a metric calculator, and the metric calculator predicts a pilot symbol from a chip level signal output from the iterative equalizer, and predicts the pilot symbol and the preset pilot. And calculating and outputting an average value of the difference between the reference signals as the metric value. The method of claim 14, The metric value is calculated based on one frame.

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