KR20170133147A - Method and apparatus for precoding signal in mobile communication system - Google Patents

Abstract

The present disclosure relates to a 5G or pre-5G communication system to support higher data rates than a 4G communication system such as LTE. A method for processing a signal in a base station included in a communication system according to an embodiment of the present disclosure includes: a process of performing layer mapping on an input signal; a process of performing a preprocess for mapping the layer-mapped layer signal to an antenna port; and a process of performing a phase shift on the preprocessed antenna port signal. It is possible to provide a method and an apparatus for processing a signal based on an open loop preprocessing method in an FD-MIMO system.

Description

TECHNICAL FIELD [0001] The present invention relates to a method and apparatus for signal processing in a communication system,

The present disclosure relates to a method and apparatus for processing signals in a communication system, and more particularly to a method and apparatus for processing signals in a full-dimension multi-input multi-output (FD-MIMO) .

Efforts have been made to develop an improved 5G (5 ^th -generation) communication system or a pre-5G communication system to meet the increasing demand for wireless data traffic after commercialization of 4G (4 ^th -generation) communication system . For this reason, a 5G communication system or a pre-5G communication system is called a beyond 4G network communication system or a long term evolution (LTE) system post (post LTE) system.

To achieve a high data rate, 5G communication systems are being considered for implementation in very high frequency (mmWave) bands (e.g., 60 gigahertz (60GHz) bands). In 5G communication system, beamforming, massive multi-input (MIMO), massive MIMO, FD-MIMO, and so on are used in order to mitigate the path loss of the radio wave in the very high frequency band and to increase the propagation distance of the radio wave. Array antennas, analog beam-forming, and large scale antenna technologies are being discussed.

In order to improve the network of the system, the 5G communication system has developed an advanced small cell, an advanced small cell, a cloud radio access network (cloud RAN), an ultra-dense network, Device-to-device communication (D2D), wireless backhaul, moving network, cooperative communication, coordinated multi-points (CoMP) cancellation and so on.

In addition, in the 5G system, hybrid frequency shift keying (FSK) and quadrature amplitude modulation (QAM) (FQAM), which are advanced coding modulation (ACM) schemes, and sliding window superposition coding a sliding window superposition coding (SWSC), an advanced connection technology, a filter bank multi carrier (FBMC), a nonorthogonal multiple access (NOMA), and a sparse code multiple access: SCMA) are being developed.

Among the 5G communication systems, the massive MIMO system can satisfy a high data rate even if only a linear pre-processing is performed in a precoder by installing multiple antennas in a base station. In addition, Massive MIMO systems are theoretically capable of completely eliminating elements that limit system performance such as noise, fast fading, and inter-user interference when using an infinite antenna. Has been studied as a core technology of next generation communication system. In massive MIMO systems, it is important that the base station has channel information with the UE in order to achieve this advantage. Researches related to the existing massive MIMO system are based on channel reciprocity from the uplink channel, (TDD) environment in which channel information of a downlink channel can be obtained in a time division duplex (TDD) environment.

However, the TDD scheme is disadvantageous in that it is less efficient than the frequency-division duplex (FDD) scheme when the distance between the base station and the UE is long or the traffic requirement of the uplink and the downlink is similar. For this reason, FDD is supported in many communication systems. Therefore, it is very essential to implement a massive MIMO system in an environment supporting the FDD scheme.

Recently, an FD-MIMO system using 16 or more antenna ports as a two-dimensional array structure has been studied as a core technology of 5G technology for massive MIMO implementation. The FD-MIMO system can perform elevation beamforming by using a planar array structure of a base station. Thus, a user-specific beamforming technique enables a high system performance There is an advantage that a gain can be obtained. In order to maximize the advantages of the FD-MIMO system, an improved performance pre-processing scheme is required in the FD-MIMO system.

One embodiment of the present disclosure provides a method and apparatus for processing a signal based on an open loop pre-processing method in an FD-MIMO system.

Also, one embodiment of the present disclosure provides a method and apparatus for processing a signal based on cyclic delay diversity in an FD-MIMO system.

Also, an embodiment of the present disclosure provides a method and apparatus for demodulating a processed signal based on an open loop pre-processing method in an FD-MIMO system.

One embodiment of the present disclosure also provides a method and apparatus for demodulating a processed signal based on cyclic delay diversity in an FD-MIMO system.

The method proposed in an embodiment of the present disclosure includes: A method of processing signals in a base station included in a communication system, the method comprising: performing layer mapping on an input signal; performing preprocessing to map the layer mapped layer signal to an antenna port; And performing a phase shift on the port signal.

Also, a method proposed in an embodiment of the present disclosure includes: A method of processing a signal in a base station included in a communication system, the method comprising: performing layer mapping on an input signal; performing pre-processing for mapping the layer-mapped layer signal to an antenna port; And performing a phase shift on the antenna port signal.

Also, an apparatus proposed in an embodiment of the present disclosure includes: A base station for processing a signal in a communication system, the base station performs a layer mapping on an input signal, performs pre-processing for mapping the layer-mapped layer signal to an antenna port, and performs a phase shift on the preprocessed antenna port signal And a transmitter for transmitting the signal processed by the controller to the terminal.

Also, an apparatus proposed in an embodiment of the present disclosure includes: A terminal for processing a signal in a communication system, the terminal comprising: a receiver for receiving a signal from a base station; and a control unit for controlling demodulation of the received signal, wherein the received signal includes a pre- And a phase shift is performed on the preprocessed antenna port signal.

Other aspects of the present disclosure, as well as benefits and key features, will be apparent to those skilled in the art from the following detailed description, which is set forth in the accompanying drawings and which discloses preferred embodiments of the disclosure.

It may be effective to define definitions for certain words and phrases used throughout this patent document before processing the specific description portions of the present disclosure below: "include" and " Comprise "and its derivatives mean inclusive inclusion; The term " or "is inclusive and means" and / or "; The terms " associated with "and " associated therewith ", as well as their derivatives, are included within, (A) to (A) to (B) to (C) to (C) to (C) Be communicable with, cooperate with, interleave, juxtapose, be proximate to, possibility to communicate with, possibility to communicate with, It means big or is bound to or with, have a property of, etc .; The term "controller" means any device, system, or portion thereof that controls at least one operation, such devices may be hardware, firmware or software, or some combination of at least two of the hardware, Lt; / RTI > It should be noted that the functionality associated with any particular controller may be centralized or distributed, and may be local or remote. Definitions for particular words and phrases are provided throughout this patent document and those skilled in the art will recognize that such definitions are not only conventional, But also to future uses of the phrases.

1 is a diagram illustrating a signal flow of a base station and a terminal in a case where a closed loop preprocessing method is used in a communication system and an open loop preprocessing method is used;
2 is a diagram illustrating an example of a case where a base station applies a CDD preprocessing method in a communication system,
Figures 3 and 4 are simplified views of a communication system to which an embodiment of the present disclosure is applied,
5 is a diagram illustrating a method of processing a signal based on a Port level LD-CDD scheme in a base station 300 according to a first embodiment of the present disclosure.
6 is a diagram illustrating a cyclic delay characteristic when a cyclic delay scaling scheme according to the second embodiment of the present disclosure is applied to the CDD scheme,
7 is a diagram illustrating an example of applying a circular area scaling scheme to a Port level LD-CDD scheme according to a second embodiment of the present disclosure;
8 is a diagram illustrating a method of processing a signal by applying a cyclic delay scaling scheme to an LD-CDD scheme in a base station 300 according to a second embodiment of the present disclosure,
9 is a diagram illustrating an example of a first effective channel configuration method in which a terminal 400 according to an embodiment of the present disclosure constructs an effective channel for demodulating a signal subjected to pre-
10 is a diagram illustrating an example of a second effective channel configuration method in which a terminal 400 according to an embodiment of the present disclosure constructs an effective channel for demodulating a pre-processed signal,
FIG. 11 is a diagram illustrating an example of a process 1011 in which a terminal 400 reconstructs an effective channel in a second effective channel configuration method according to an embodiment of the present disclosure.
12 is a simplified illustration of an internal configuration of a base station 300 for processing signals in a communication system according to an embodiment of the present disclosure;
13 is a simplified illustration of the internal configuration of a terminal 400 for processing signals in a communication system according to an embodiment of the present disclosure,
14 is a graph illustrating performance according to the number of antenna ports when a conventional layer level CDD scheme is applied to a base station and when a port level CDD scheme according to the first embodiment of the present disclosure is applied;
15 is a diagram illustrating a bit error rate (BER) performance when a conventional layer-level CDD scheme is applied to a base station and when a port level CDD scheme according to the first embodiment of the present disclosure is applied;
16 is a diagram illustrating a BER performance according to a channel state when a conventional layer-level CDD scheme is applied to a base station and when a port level CDD scheme according to the first embodiment of the present disclosure is applied.
Throughout the drawings, it should be noted that like reference numerals are used to illustrate the same or similar elements and features and structures.

The following detailed description, which refers to the accompanying drawings, will serve to provide a comprehensive understanding of the various embodiments of the present disclosure, which are defined by the claims and the equivalents of the claims. The following detailed description includes various specific details for the sake of understanding, but will be considered as exemplary only. Accordingly, those skilled in the art will recognize that various changes and modifications of the various embodiments described herein may be made without departing from the scope and spirit of this disclosure. Furthermore, the descriptions of well-known functions and constructions may be omitted for clarity and conciseness.

The terms and words used in the following detailed description and in the claims are not intended to be limited to the literal sense, but merely to enable a clear and consistent understanding of the disclosure by the inventor. It is therefore to be understood by those skilled in the art that the following detailed description of various embodiments of the disclosure is provided for illustrative purposes only and is not intended to limit the present disclosure as defined by the appended claims and equivalents of the claims It should be clear that this is not provided for.

It is also to be understood that the singular forms "a" and "an" above, which do not expressly state otherwise in this specification, include plural representations. Thus, in one example, a "component surface" includes one or more component representations.

Also, terms including ordinal numbers such as first, second, etc. may be used to describe various elements, but the elements are not limited to these terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present disclosure, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. And / or < / RTI > includes any combination of a plurality of related listed items or any of a plurality of related listed items.

Furthermore, the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting on the present disclosure. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms "comprises" or "having" and the like refer to the presence of stated features, integers, steps, operations, elements, components, or combinations thereof, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Also, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Terms such as those defined in commonly used dictionaries should be understood to have a meaning consistent with the contextual meaning of the related art.

The preprocessor included in the base station in the communication system performs preprocessing on the input signal using one of the open-loop precoding method and the closed-loop precoding method.

FIG. 1 shows a signal flow of a base station and a terminal when a closed loop preprocessing method and an open loop preprocessing method are used in a communication system.

1, when a base station 110 performs a preprocessing using a closed loop preprocessing method, the base station 110 transmits a reference signal for transmission to a channel to the terminal 130 (151). Here, the reference signal includes a channel reference signal (CRS) and a channel state indicator-reference signal (CSI-RS).

Upon receiving the reference signal from the base station 110, the terminal 130 estimates a channel between the base station 110 and the terminal 130 and feeds back information about the estimated channel to the base station 153 (153). Herein, the estimated channel information basically includes a channel quality indicator (CQI) and a rank indicator (RI) for a modulation and coding scheme (MCS). In addition, when the UE 130 receives a signal from the BS 110 using the closed loop preprocessing method, the precoding matrix indicator (PMI) is used as information on the channel matrix in addition to the CQI and the RI, ).

Thereafter, the base station 110 performs a closed loop pre-processing on the input signal based on the feedback PMI, CQI, and RI (155). Then, the BS 110 transmits a closed loop pre-processed signal to the MS 130 (step 157). Then, the terminal 130 demodulates the signal received from the base station 110 (159).

(B), the BS 110 transmits a CRS message to the MS 130 (step 171), and then transmits the CRS to the MS 130, which is estimated from the MS 130, (I.e., CQI and RI) (step 173). However, the base station 110 does not perform the pre-processing on the basis of the information fed back from the terminal 130, but processes the signal using the pre-determined open loop pre-processing method in the time frequency domain with the terminal 130 175). Then, the base station 110 transmits the signal subjected to the open loop preprocessing to the terminal 130 (177). Then, the terminal 130 demodulates the signal received from the base station 110 using the pre-determined open-loop pre-processing method (179).

For example, when the base station 110 supports the terminal 130 using the transmission mode 3 for performing the open loop pre-processing among the transmission modes used in the LTE system, Pre-processing is performed for each subcarrier. The terminal 130 may perform a pre-processing based on a sub-carrier index to demodulate the received signal.

Such an open loop preprocessing method has a performance loss compared to the closed loop preprocessing method based on the channel information fed back from the terminal at the base station. However, the open loop preprocessing method is suitable for supporting highly mobile terminals or channels that change rapidly with time. In particular, when the open loop pre-processing method is applied to an FD-MIMO system capable of flexible antenna virtualization, it is possible to maximize the advantages of the FD-MIMO system in that it can support terminals of various states. Also, in the FD-MIMO system assuming a very large number of antennas, feedback of the channel information from the UE to the base station may be very difficult in a limited feedback environment. Therefore, the open loop preprocessing method requires a closed loop There is an advantage over the pre-processing method in terms of the feedback overhead required for performance.

Considering the advantages of the open loop pre-processing method as described above, the embodiments of the present disclosure propose a method of further enhancing the advantage of the open loop pre-processing method suitable for an FD-MIMO system. Particularly, in the embodiment of the present disclosure, an open loop preprocessing method based on a cyclic delay diversity (CDD) method (hereinafter referred to as a CDD preprocessing method) is proposed. The CDD preprocessing method can obtain a performance gain in terms of link reliability without any additional feedback, and will be described in detail with reference to FIG.

FIG. 2 shows an example of a case where a base station applies a CDD preprocessing method in a communication system. In FIG. 2, the communication system is an orthogonal frequency division multiplexing (OFDM) system. However, the CDD preprocessing method based on FIG. 2 may be applied to other communication systems.

Referring to FIG. 2, the unit related to the pre-processing in the OFDM system includes a pre-processing unit 230 and an inverse fast fourier transform (IFFT) unit 250.

The preprocessor 230 performs a phase shift on a transmission signal 210 carried on each subcarrier in proportion to a subcarrier index and transmits the phase shift to the IFFT unit 250. Then, the IFFT unit 250 can output a signal having a cyclic delay in a time domain as shown in Equation (1) below.

&Quot; (1) "

는 순환 지연 값(cyclic delay value), N _FFT는 IFFT의 FFT 사이즈(size), k는 부반송파 인덱스, X(k)는 부반송파 k에 실리는 주파수 영역의 송신 신호, l은 시간 인덱스(time index), x[l]은 시간 인덱스 l에 해당하는 시간 영역의 송신 신호이다.here

Is a cyclic delay value (cyclic delay value), N _FFT is the FFT size (size) of the IFFT, k is a subcarrier index, X (k) is the transmitted signal, l in the frequency domain carried on the sub-carrier k is the time index (time index) , x [ l ] is a time-domain transmission signal corresponding to the time index l .

As described above, when a base station using multiple antennas uses a plurality of cyclic delay values (i.e., a CDD pre-processing method is used), a frequency selectivity in a frequency region of an effective channel after a pre- Can be increased. In addition, since the frequency selectivity of the base station can be increased, the channel coding gain can be increased.

The communication system applying the CDD preprocessing method as shown in FIG. 2 may be configured as shown in FIGS. 3 and 4. FIG. 3 and 4 show a communication system to which the embodiment of the present disclosure is applied. In particular, FIG. 3 shows the configuration of the base station in the communication system, and FIG. 4 shows the configuration of the terminal in the communication system. An overview of the CDD preprocessing method described below and a description of embodiments of the present disclosure will be made with reference to FIGS. 3 and 4. FIG.

Referring to FIG. 3, in the communication system, the base station 300 may transmit one or more code work (CW) on the downlink. That is, each of the one or more CWs is processed as a complex symbol through the corresponding scramblers 301-1 to 301-n and the modulation mappers 303-1 to 303-n. Thereafter, the complex symbol is mapped to a plurality of layers by a layer mapper 305, and a symbol mapped to each layer is preprocessed by a preprocessor 307 to map to each transmit antenna port.

The transmission signals for each antenna port thus processed are mapped to time-frequency resource elements to be used for transmission by the resource element mappers 309-1 to 309-n, respectively, and OFDM signal generators 311-1 to 311-n ≪ / RTI > to the OFDM signal. Each of the OFDM signals may be transmitted through each antenna port through IFFT units 315-1 to 315-n and cyclic prefix (CP) inserters 315-1 to 315-7.

In particular, the preprocessing unit 307 performs CDD preprocessing based on Equation (2) below.

&Quot; (2) "

는 주파수 영역에서 안테나 포트 신호(antenna port signal) 를 나타낸 것이다. 여기서 i는 레이어 인덱스(layer index), s는 안테나 포트 신호, x는 레이어 신호(layer signal), U는 레이어 다중화 행렬(layer multiplexing matrix), D는 위상 천이(phase shift)를 위한 대각 행렬(diagonal matrix), W는 전처리 행렬을 나타낸다. In Equation (2)

Represents an antenna port signal in the frequency domain. Where i is a layer index, s is an antenna port signal, x is a layer signal, U is a layer multiplexing matrix, D is a diagonal matrix for phase shift, matrix), and W represents a preprocessing matrix.

In other words, the preprocessing unit 307 of FIG. 3 performs a preprocessing by mapping a layer signal to an antenna port signal, and performs a phase shift by applying a diagonal matrix for phase shift to a preprocessed antenna port signal. Here, the operation of applying the diagonal matrix for phase shift to the preprocessed antenna port signal may be processed in a separate unit after the preprocessing unit 307. [

Referring to FIG. 4, the BS 300 transmits a signal to the MS 400 based on a physical downlink shared channel (PDSCH). At this time, the signal transmitted from the base station 300 is received at the terminal 400 after experiencing the MIMO channel environment. The signals received from the terminal 400 are converted into frequency-domain signals through the CP removers 401-1 to 401-n and the FFT units 403-1 to 403-n. At this time, the signal converted into the frequency domain signal can be expressed as Equation (3) below.

&Quot; (3) "

Here, s ( i ) is the antenna port signal of the base station 300 shown in Equation (3), y ( i ) is the reception signal of the terminal 400 corresponding to the layer index i , H ( i ) MIMO channel, and n ( i ) denotes a noise signal in the reception process. All the signals shown in Equation (3) are frequency-domain signals.

Then, the frequency-domain signals are demodulated through demodulators 407-1 to 407-n via a MIMO detector 405. [

The CDD preprocessing method performed in the preprocessing unit 307 of the communication system shown in FIG. 3 and FIG. 4 may include a preprocessing method based on a large delay CDD (hereinafter referred to as LD-CDD) And a preprocessing method based on a small delay CDD (hereinafter referred to as SD-CDD) method. For convenience of explanation, the following description will be made on the assumption that the CDD preprocessing method is the LD-CDD method, but the present invention is not limited thereto, and the present disclosure is also applicable to the LD-CDD method.

Hereinafter, it is assumed that the LD-CDD method is applied in the preprocessing method according to the embodiment of the present disclosure. In the LD-CDD scheme applied in the embodiment of the present disclosure, it is assumed that a signal transmitted from each antenna has a cyclic delay difference of N _FFT / D. Where D is the size of the row / column of matrix D. In this case, if D is equal to the number of layers, it is defined as a layer level (CDD) and a port level (CDD) if the number is equal to the number of antenna ports. In the current standard, a layer-level LD-CDD scheme supporting up to four layers is used. For this purpose, a diagonal matrix for phase shift represented by D ( i ) in Equation (2) D _layer ( i ) in Equation (4) below.

&Quot; (4) "

Where v is the number of layers.

The effect of the preprocessing method based on the LD-CDD scheme (hereinafter referred to as LD-CDD preprocessing method) according to D is to increase the phase shift applied to each subcarrier in proportion to the subcarrier index. That is, in the case of the LD-CDD pre-processing method, it can be confirmed that the same phase shift is applied to the transmission signal for each of the D subcarriers as shown in Equation (5) below.

Equation (5)

As shown in Equation (5), when the same phase shift is applied to the transmission signal, it means that the frequency selectivity of the two effective channels changes in the same manner. Therefore, it can be said that the correlation change of the effective channel due to the CDD preprocessing method occurs with respect to the effective channel corresponding to the adjacent 2 D -2 subcarriers. Based on the characteristics of the CDD preprocessing method, the present embodiment proposes a CDD preprocessing method suitable for the following two FD-MIMO systems.

First, the first embodiment of the present invention performs a signal processing method based on the Port level LD-CDD method in the base station 300. [

Currently, the CDD preprocessing method used in the 3GPP LTE standard acquires the CDD gain by applying a phase shift to each layer. However, the gain can not be sufficiently obtained in the FD-MIMO system in which the base station 300 uses a very large number of antennas. LD-CDD Preprocessing As the diagonal matrix for phase shift increases, the number of subcarriers that can reduce the correlation increases because the correlation between the effective channels of adjacent 2 D- 2 subcarriers is reduced. This means a decrease in the correlation of the average effective channel, so that an increase in channel coding gain can be expected. In this respect, in the case where the number of antenna ports is larger than the number of layers, a preprocessing method based on a port level LD-CDD method of applying a phase shift to an antenna port signal is more preferable than a preprocessing method based on a layer level LD- A high performance gain can be expected. The preprocessing method based on the port level LD-CDD method is expected to be more suitable for the FD-MIMO system which can use a very large number of antenna ports.

Referring to FIG. 3, the port level LD-CDD scheme refers to a case where the size of the diagonal matrix for phase shift is equal to the number of antenna ports. Therefore, the base station 300 according to the first embodiment of the present invention maps a layer signal to an antenna port signal and performs preprocessing, and then applies a diagonal matrix for phase shift to the preprocessed signal.

For example, the base station 300 according to the first embodiment of the present disclosure performs pre-processing for mapping an input layer signal to an antenna port signal based on Equation (6) below, and performs phase processing on the preprocessed antenna port signal Can be performed.

&Quot; (6) "

Here, the matrix D _port is an antenna port signal. Based on Equation (7), the base station 300 performs a phase shift by applying a diagonal matrix for phase shift to the matrix D _port of Equation (6). Equation (6) is an example of a preprocessing method based on the port level LD-CDD method in the preprocessing unit 307, and can be changed to a structure such as adding a matrix for multiplexing to an antenna port signal Do.

&Quot; (7) "

Where the size D of the matrix D _port is equal to the number P of antenna ports.

In the signal processing method based on the Port level LD-CDD method according to the first embodiment of the present disclosure, when the number of antenna ports is larger than the number of layers, the number of cyclic delays is increased compared to the layer level LD- It is possible to obtain an average decrease in the correlation between the effective channels of the subcarriers.

5, a pre-processing method in which the base station 300 and the terminal 400 are prearranged in the time-frequency domain is a signal processing method based on the Port level LD-CDD method according to the first embodiment of the present disclosure The operation of the base station 300 will be described.

FIG. 5 illustrates a method of performing signal processing based on the Port level LD-CDD method in the base station 300 according to the first embodiment of the present disclosure.

Referring to FIG. 5, the base station 300 performs layer mapping on an input signal (501). The base station 300 performs pre-processing for mapping the layer-mapped layer signal to an antenna port (step 503).

Thereafter, the base station 300 performs a phase shift by applying a diagonal matrix for phase shift to the preprocessed antenna port signal (505).

For example, the base station 300 maps an antenna port signal to at least one layer signal based on Equation (6) and Equation (7) to perform preprocessing, A diagonal matrix for < / RTI >

Therefore, when the base station 300 and the terminal 400 make a preliminary commitment to use the signal processing method based on the Portlevel LD-CDD scheme according to the first embodiment of the present disclosure in the preprocessing method, Performs processing based on the Port level LD-CDD scheme pre-agreed with the terminal 400, and transmits the processed signal to the terminal 400. [ Here, the processed signal means a phase-shifted signal after the preprocessing is performed. Since the terminal 400 knows the preprocessing method processed in the base station 300 in advance, the terminal 400 does not transmit / receive additional information to / from the base station 300, and demodulates the received signal based on the pre-determined Port level LD- can do.

A signal processing method based on the Port level LD-CDD method according to the first embodiment of the present disclosure has been described above, and a signal processing method according to the second embodiment of the present disclosure will be described below.

The second embodiment of the present disclosure applies a cyclic delay scaling method to the CDD method when the pre-processing unit 307 performs the preprocessing. The second embodiment of the present disclosure can be applied after the signal processing method according to the first embodiment of the present disclosure has been performed, or can be applied to a conventional method of preprocessing without performing the signal processing method according to the first embodiment of the present disclosure Method can be applied.

The cyclic delay scaling method for applying the CDD scheme in the second embodiment of the present disclosure is a method for generating a random cyclic delay value by using the fact that the cyclic delay value of rotation value with a N _FFT -1 to a maximum value. In detail, the cyclic delay scaling method applied to the CDD scheme according to the second embodiment of the present disclosure can be performed by the base station 300 as shown in Equation (10), for example.

That is, the conventional layer-level CDD scheme outputs a signal as shown in Equation (8) below for each layer, and the Port level CDD scheme according to the first embodiment of the present disclosure generates a signal such as Equation (9) .

&Quot; (8) &quot;

Here, v is the number of layers.

&Quot; (9) &quot;

Where N _T is the number of transmit antennas.

For example, when the cyclic delay scaling method according to the second embodiment of the present disclosure is applied to the port level CDD method according to the first embodiment of the present disclosure, the base station 300 transmits a signal as shown in Equation (10) Can be output.

&Quot; (10) &quot;

는 순환 지연 스케일링 팩터로, 0<

<N_T로 정의되고,

는 N_FFT보다 큰 값을 가진다.here,

Is a cyclic delay scaling factor, 0 <

&Lt; N _T ,

_Has a larger value than the N _FFT .

Equation (10) can be used as shown in FIG.

)가 3/2인 경우를 가정한다.FIG. 6 shows a cyclic delay characteristic when the cyclic delay scaling method according to the second embodiment of the present disclosure is applied to the CDD method. 6, the preprocessing unit 307 uses a signal processing method based on the port level LD-CDD method according to the first embodiment of the present disclosure, and the number of antenna ports is four, and a cyclic delay scaling factor scaling factor,

) Is 3/2.

Referring to FIG. 6, when the base station 300 performs pre-processing based on the port level LD-CDD method, it is confirmed that a cyclic delay difference of N _FFT / 4 exists for each antenna port as shown in (a) . In addition, if the cyclic delay scaling factor is applied to the port level LD-CDD scheme according to the second embodiment of the present invention after the base station 300 performs the preprocessing, 3 N _FFT / 8. When the base station 300 applies the cyclic delay scaling factor to the Port level LD-CDD scheme according to the second embodiment of the present disclosure, the cyclic delay characteristic becomes irregular when compared with the case where the cyclic delay scaling factor is not applied In particular, it can be seen that the maximum value of the cyclic delay difference per antenna port increases to 7 N _FFT / 8. And the increase of the maximum value of the cyclic delay difference according to the antenna port increases the frequency selectivity of the effective channel and increases the channel coding gain.

For example, when the base station 300 performing the pre-processing method according to the second embodiment of the present disclosure applies the assumption of FIG. 6 to Equation (7) described in the first embodiment of the present disclosure, A matrix can be output.

FIG. 7 shows an example of applying a circular area scaling scheme to a Port level LD-CDD scheme according to the second embodiment of the present disclosure. FIG. 7 illustrates a case in which the maximum value of the cyclic delay difference for each antenna port increases in a case where the cyclic delay scaling method is not applied in terms of correlation between two effective channels in the frequency domain, And the case (b).

)를 적용하면,(b)와 같은 행렬 D를 출력할 수 있다. 따라서, 본 개시의 제2 실시 예에 따른 전처리 방법은(b)와 같이 유효 채널의 상관도가 줄어드는 인접한 부반송파의 수를 증가시켜 평균적인 유효 채널 간 상관도를 줄일 수 있다. 이때, 위상 천이를 위한 대각 행렬은, 상기 <수학식 5>와 같이 D개의 부반송파마다 반복됨을 확인할 수 있다.Referring to FIG. 7, according to the second embodiment of the present disclosure, the preprocessing unit 307 adds a cyclic delay scaling factor (a) for applying the cyclic delay scaling scheme to the Port level LD-

), It is possible to output the matrix D as shown in (b). Therefore, the preprocessing method according to the second embodiment of the present disclosure increases the number of adjacent subcarriers in which the correlation of the effective channels is reduced as shown in (b), and thereby reduces the correlation between the average effective channels. At this time, it can be confirmed that the diagonal matrix for phase shift is repeated for every D subcarriers as in Equation (5).

Therefore, the preprocessing method according to the second embodiment of the present disclosure applies a cyclic delay scaling scheme to the LD-CDD scheme, thereby enhancing the performance gain through the preprocessing process. At this time, in the pre-processing method according to the second embodiment of the present disclosure, the obtainable performance gain differs according to the cyclic delay scaling factor applied to the LD-CDD scheme. Therefore, the base station 300 must determine the cyclic delay scaling factor based on at least one of the number of antenna ports and the state of the current channel. Since the cyclic delay scaling factor is not a predetermined parameter between the base station 300 and the terminal 400, the base station 300 must transmit the determined cyclic delay scaling factor to the terminal 400. In detail, the operation of the base station 300 performing the preprocessing method according to the second embodiment of the present disclosure will be described with reference to FIG.

FIG. 8 shows a method of performing preprocessing by applying a cyclic delay scaling scheme to the LD-CDD scheme in the base station 300 according to the second embodiment of the present disclosure.

First, since the channel selectivity of the effective channel has a significant effect on performance, the CDD pre-processing method requires information on the frequency selectivity of the physical channel in the process of determining the cyclic delay scaling factor. However, the base station 300 using the current CDD preprocessing method does not have a feedback signal that can acquire information for estimating the frequency selectivity of the channel. Therefore, the base station 300 uses an uplink sounding reference signal (SRS) transmitted from the terminal 400 to acquire information for estimating the frequency selectivity of the channel.

That is, referring to FIG. 8, the BS 300 receives the uplink SRS from the MS 400 (801). The base station 300 estimates the frequency selectivity of the uplink channel from the received uplink SRS using the characteristic that the frequency selectivity of the uplink channel and the downlink channel are similar to each other, Is determined as the state of the downlink channel (i.e., frequency selectivity) (803).

Then, the BS 300 determines a cyclic delay scaling factor based on the state of the downlink channel and the number of antenna ports (step 805), and transmits the determined cyclic delay scaling factor to the terminal 400 (step 807). Then, the base station 300 performs preprocessing by applying the CDD method to the layer signal input according to the pre-determined pre-processing method with the terminal 400 (809). Next, the base station 300 transmits a phase-shifted signal to the terminal 400 based on the cyclic delay scaling factor for the pre-processed signal (811). Since the terminal 400 receives the cyclic delay scaling factor from the base station 300, the terminal 400 demodulates the signal received from the base station 300 using the cyclic delay scaling factor based on the pre- can do.

The pre-determined pre-processing method between the base station 300 and the terminal 400 may be a method according to the second embodiment of the present disclosure, a signal processing method according to the first embodiment of the present disclosure, or a conventional preprocessing method. When the pre-determined pre-processing method between the base station 300 and the terminal 400 is the signal processing method or the conventional preprocessing method according to the first embodiment of the present disclosure, the base station 300 determines the cyclic delay scaling factor The cyclic delay scaling factor may be applied in addition to the signal processing method or the conventional preprocessing method according to the first embodiment of the present disclosure.

A description has been given of a method of processing signals in the base station 300 and receiving processed signals from the base station 300 in the terminal 400 according to the first and second embodiments of the present disclosure. A method for configuring an effective channel for demodulating a signal received from the base station 300 will be described.

In the conventional CDD preprocessing method, when the BS 300 transmits a physical channel to the MS 400 using the CRS, the MS 400 interpolates the physical channel in the resource block (RE) A valid channel was constructed by adding information about the pre-promised pre-processing method. However, since the CRS can support only a maximum of four antenna ports, a new channel transmission scheme between the base station 300 and the terminal 400 is required in the FD-MIMO system assuming 16 or more antenna ports.

To this end, methods for constructing an effective channel for demodulating a signal received at the terminal 400 in the embodiment of the present disclosure based on FIGS. 9 and 10 will be described. Methods for configuring the effective channel of the terminal 400 may be configured by the following two methods.

The first effective channel configuration method is for the base station 300 to transmit information on the physical channel to the UE 400 using the CSI-RS. Then, based on the pre-determined pre-processing method (i.e., at least one of the signal processing method according to the first embodiment of the present invention and the signal processing method according to the second embodiment) of the terminal 400, The channel can be configured as a valid channel.

The second effective channel configuration method is such that when the base station 300 transmits the information on the effective channel directly to the terminal 400 using the DMRS, the terminal 400 reconstructs the effective channel.

FIG. 9 shows an example of a first effective channel configuration method in which a terminal 400 according to an embodiment of the present disclosure constructs an effective channel for demodulating a signal subjected to pre-processing.

First, it is assumed that the MS 400 knows a CDD preprocessing method used in the base station 300, a preprocessing matrix W used in each sub-carrier, a diagonal matrix D for phase shift, and a layer multiplexing matrix U. However, in the FD-MIMO system, since it is difficult to transmit a channel using the CRS used for transmitting a channel in the conventional technique, the base station 300 uses a CSI-RS supporting more than 8 antenna ports, (901). Then, the terminal 400 interpolates the physical channel received from the base station 300 (903). Then, the terminal 400 configures the interpolated physical channel as an effective channel based on previously known pre-processing information (905).

The terminal 400 receives the processed signal from the base station 300 (907), and demodulates the received signal based on the effective channel (909).

FIG. 10 shows an example of a second effective channel configuration method in which a terminal 400 according to an embodiment of the present disclosure constructs an effective channel for demodulating a signal subjected to pre-processing. Here, the second effective channel configuration method is a method in which the base station 300 directly transmits the information on the effective channel to the terminal 400. In particular, referring to FIG. 10, the base station 300 determines an RE for transmitting information on an effective channel to the terminal 400, and determines whether the terminal 400 is an effective channel based on the effective channel received from the base station 300, Will be described.

Referring to FIG. 10, the BS 300 receives an SRS from the MS 400 (100). The base station 300 estimates the frequency selectivity of the uplink channel based on the received SRS (1003). The BS 300 determines an RS for transmitting RS overhead and information on an effective channel based on the frequency selectivity of the estimated uplink channel (step 1005). Then, the BS 300 transmits the determined RE information to the MS 400 (1007) and directly transmits information on the valid channel using the determined RE (1009). If the number of antenna ports of the base station 300 is very large, RS overhead for transmission of an effective channel increases in proportion to the number of antenna ports. In order to solve this problem, when the base station 300 directly transmits the information on the effective channel to the terminal 400 as in the embodiment of the present disclosure, when the number of layers is smaller than the number of the antenna ports, . However, when the CDD preprocessing method is used in the base station 300 according to the first and second embodiments of the present disclosure, the frequency selectivity of the effective channel becomes very high. This makes it impossible for the base station 300 to directly interpolate the effective channel after estimating the effective channel in some REs. Accordingly, after receiving the effective channel from the base station 300, the terminal 400 constructs an effective channel for the remaining RE using the received effective channel (step 1011). Hereinafter, a method of configuring an effective channel by the terminal 400 will be described in detail with reference to FIG.

Then, the terminal 400 receives the processed signal from the base station 300 (1013), and demodulates the received signal based on the reconstructed effective channel (1015).

FIG. 11 illustrates an example of a procedure (1011) in which a terminal 400 reconstructs an effective channel in a second effective channel configuration method according to an embodiment of the present disclosure.

Referring to FIG. 11, a procedure (1011) of reconstructing an effective channel by the MS 400 includes an operation 1101 for estimating a physical channel and an operation 1103 for configuring an effective channel.

The operation 1101 of estimating the physical channel is an operation of inverse computing a physical channel. That is, since the physical channel is low in frequency selectivity with respect to the effective channel, the terminal 400 can inversely calculate the physical channel from the effective channel received from the base station 300 and then interpolate the physical channel corresponding to the remaining RE. At this time, if the number of layers is smaller than the number of antenna ports in the MS 400, since information on the entire physical channels in the effective channel corresponding to the RE transmitted by the base station 300 can not be known, To estimate the physical channel (1011). For example, if the number of antenna ports is 4 and the number of layers is 2 in the system, and RE is used for transmission of information on the effective channel at intervals of C subcarriers, the terminal 400 determines that the channel is not changed in the C subcarriers , The physical channel corresponding to the subcarrier k + i ( i = 0, 1, ..., C ) can be estimated.

Next, the MS 400 reconstructs the estimated physical channel into an effective channel based on the pre-processing information used in the BS 300 (1103). At this time, the MS 400 may configure the effective channel for the subcarrier k + i by Equation (11) in consideration of the physical channel estimated by the physical channel estimation operation 1101.

Equation (11)

와

는 각각 부반송파 k에 해당하는 유효 채널과 기지국(300)에서 사용된 전처리 정보이다. 유효 채널에 대한 정보를 기지국(300)이 직접 전송하는 방식은 안테나 포트의 수보다 레이어의 수가 적을 경우 RS 오버헤드를 줄일 수 있다는 장점이 있다. 그러나 기지국(300)이 CDD 전처리 방법을 이용하는 경우 유효 채널의 주파수 선택성이 높기 때문에 물리 채널의 선택성에 따라 RS 오버헤드에 해당하는 C 값을 결정하여 단말(400)로 전송해야 한다.here,

Wow

Are effective channels corresponding to the subcarrier k and pre-processing information used in the base station 300, respectively. The method in which the base station 300 directly transmits information on an effective channel has an advantage that RS overhead can be reduced when the number of layers is smaller than the number of antenna ports. However, when the base station 300 uses the CDD preprocessing method, since the frequency selectivity of the effective channel is high, it is necessary to determine the C value corresponding to the RS overhead according to the selectivity of the physical channel and transmit it to the terminal 400.

In the above description, methods for constructing an effective channel for demodulating a signal processed from the base station 300 according to the embodiment of the present disclosure have been described. Hereinafter, based on FIGS. 12 and 13, The internal configuration of the base station 300 and the terminal 400 performing the examples will be briefly described.

12 shows an internal configuration of a base station 300 that processes signals in a communication system according to an embodiment of the present disclosure. Although the main unit for performing the pre-processing method according to the embodiments of the present disclosure in the base station 300 is the preprocessing unit 307, the operation of generating and transmitting the necessary information and signals for performing the preprocessing can be performed in another unit have. The internal structure shown in FIG. 12 is not limited to any one unit included in the base station 300, but simply shows the structure of the entire base station 300. FIG.

12, the base station 300 includes a control unit 1201, a transmission unit 1203, a reception unit 1205, and a storage unit 1207.

The control unit 1201 controls the overall operation of the base station 300 and in particular controls operations related to the operation of processing signals according to the embodiments of the present disclosure. The operation related to the operation of the signal processing according to the embodiment of the present disclosure is the same as that described above with reference to FIG. 3 to FIG. 11, and a detailed description thereof will be omitted here.

The transmitter 1203 receives various signals and various messages from other entities included in the communication system under the control of the controller 1201. [ Here, the various signals and various messages received by the transmitter 1203 are the same as those described with reference to FIGS. 3 to 11, and a detailed description thereof will be omitted.

The receiving unit 1205 receives various signals and various messages from other entities included in the communication system under the control of the controller 1201. [ Here, various signals and various messages received by the receiving unit 1205 are the same as those described with reference to FIG. 3 to FIG. 11, and a detailed description thereof will be omitted here.

The storage unit 1207 stores programs and various data related to operations related to an operation of processing signals according to the embodiment of the present disclosure performed by the base station 300 under the control of the controller 1201. [ Also, the storage unit 1207 stores various signals and various messages received by the receiving unit 1205 from the other entities.

12 shows a case where the base station 300 is implemented as separate units such as the control unit 1201, the transmission unit 1203, the reception unit 1205 and the storage unit 1207. However, It is needless to say that at least two of the control unit 1201, the transmission unit 1203, the reception unit 1205 and the storage unit 1207 may be integrated. In addition, the base station 300 may be implemented as a single processor.

13 shows an internal configuration of a terminal 400 that processes signals in a communication system according to an embodiment of the present disclosure. Although the main unit performing effective channel configuration and signal demodulation according to the embodiments of the present disclosure in the terminal 400 is a demodulation unit, the operation of generating and transmitting information and signals necessary for performing effective channel configuration and signal demodulation And may be performed in another unit. The internal configuration shown in FIG. 13 is not limited to any one unit included in the terminal 400, but shows the configuration of the entire terminal 400 in a simplified manner.

13, the terminal 400 includes a control unit 1301, a transmission unit 1303, a reception unit 1305, and a storage unit 1307.

The controller 1301 controls the overall operation of the terminal 400 and in particular controls operations related to the operation of processing signals according to the embodiments of the present disclosure. Operations related to the signal processing according to the embodiment of the present disclosure are the same as those described above with reference to FIG. 4 and FIGS. 9 to 11, and a detailed description thereof will be omitted here.

Under the control of the controller 1301, the transmitter 1303 receives various signals and various messages from other entities included in the communication system. Here, various signals and various messages received by the transmitter 1303 are the same as those described with reference to FIG. 4 and FIG. 9 to FIG. 11, and a detailed description thereof will be omitted.

Also, the receiver 1305 receives various signals and various messages from other entities included in the communication system under the control of the controller 1301. Here, various signals and various messages received by the receiving unit 1305 are the same as those described with reference to FIG. 4 and FIG. 9 to FIG. 11, and a detailed description thereof will be omitted here.

The storage unit 1307 stores programs and various data related to the operation related to the operation of the signal according to the embodiment of the present disclosure performed by the terminal 400 under the control of the controller 1301. [ Also, the storage unit 1307 stores various signals and various messages received by the receiving unit 1305 from the other entities.

13 shows a case where the terminal 400 is implemented as separate units such as the control unit 1301, the transmission unit 1303, the reception unit 1305 and the storage unit 1307. However, It is needless to say that at least two of the control unit 1301, the transmission unit 1303, the reception unit 1305 and the storage unit 1307 may be integrated. In addition, the base station 300 may be implemented as a single processor.

12 and 13, the internal configuration of the base station 300 and the terminal 400 that performs the embodiments of the present disclosure has been described. Hereinafter, the embodiments of the present disclosure will be described with reference to the base station 300 and the terminal 400 ) Will now be described.

FIG. 14 shows performance according to the number of antenna ports when the conventional layer level CDD scheme is applied to the base station and when the port level CDD scheme according to the first embodiment of the present disclosure is applied.

14, when the conventional layer-level CDD scheme is applied during the preprocessing in the base station, the performance change according to the number of the antenna ports is insufficient, whereas when the port level CDD scheme is applied, the outage capacity outage capacity increased by 5%. If the base station applies the port level CDD scheme according to the first embodiment of the present disclosure, the outage capacity can be increased and link reliability can be increased.

FIG. 15 shows bit error rate (BER) performance when a conventional layer-level CDD scheme is applied to a base station and when a port level CDD scheme according to the first embodiment of the present disclosure is applied.

Referring to FIG. 15, it can be seen that the port level CDD scheme according to the first embodiment of the present invention has a performance gain in terms of diversity compared to the case where the conventional layer level CDD scheme is applied to the base station. It can be confirmed that the CDD precoding performance is improved when the circulating delay scaling method according to the second embodiment of the present invention is applied to the port lever CDD method according to the first embodiment of the present disclosure.

FIG. 16 shows BER performance according to the channel state when the conventional layer level CDD scheme is applied to the base station and when the port level CDD scheme according to the first embodiment of the present disclosure is applied.

Referring to FIG. 16, it can be seen that when a port level CDD scheme according to the first embodiment of the present disclosure is applied to a base station, a gain in precoding performance increases in a high mobility environment with high channel selectivity . In the case where the circulation delay scaling method according to the second embodiment of the present disclosure is applied to the base station, it can be seen that the performance gain is remarkably generated in an environment with low mobility.

While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. Therefore, the scope of the present disclosure should not be limited to the embodiments described, but should be determined by the scope of the appended claims, as well as the appended claims.

Claims (24)

A method of processing a signal at a base station (BS) included in a communication system,
Performing layer mapping on an input signal;
Mapping a layer-mapped layer signal to an antenna port;
And performing a phase shift on the preprocessed antenna port signal.
The method of claim 1, further comprising applying a cyclic delay scaling factor for cyclic delay to the phase-shifted signal.
3. The method of claim 2, wherein the cyclic delay scaling factor comprises:
The number of antenna ports included in the base station, and the channel state of the downlink channel.
4. The method of claim 3, wherein the channel state of the downlink channel is determined by:
Wherein the uplink channel has the same frequency selectivity as the frequency selectivity of the uplink channel based on a sounding reference signal (SRS) received via an uplink channel.
The method according to claim 1,
And transmitting a channel state indicator-reference signal (CSI-RS) including information on a physical channel for transmitting the phase shifted signal to the UE.
The method according to claim 1,
Determining a resource element for transmitting an effective channel for transmitting the phase shifted signal based on a frequency selectivity of an uplink channel and transmitting information on the resource element to the terminal;
And transmitting information on the effective channel through the resource element.
A method for processing a signal in a terminal included in a communication system,
Receiving a signal from a base station,
And demodulating the received signal,
Wherein the received signal is a signal obtained by performing a phase shift on the preprocessed antenna port signal after pre-processing for mapping to an antenna port by the base station.
The signal processing method according to claim 7, wherein the received signal is a signal obtained by applying a cyclic delay scaling factor for cyclic delay to a signal obtained by performing the phase shift by the base station.
9. The method of claim 8, wherein the cyclic delay scaling factor comprises:
The number of antenna ports included in the base station, and the channel state of the downlink channel.
The method as claimed in claim 9,
Wherein the uplink channel has the same frequency selectivity as the frequency selectivity of the uplink channel based on a sounding reference signal (SRS) received via an uplink channel.
8. The method of claim 7,
Receiving a channel state indicator-reference signal (CSI-RS) including information on a physical channel for transmitting the phase-shifted signal from the base station;
And configuring an effective channel based on information on the received physical channel.
8. The method of claim 7,
Receiving information on a determined resource element for transmitting an effective channel for transmitting the phase shifted signal based on a frequency selectivity of an uplink channel from the base station;
Receiving information on the effective channel from the base station;
And configuring an effective channel based on information on the resource element and information on the effective channel.
A base station for processing a signal in a communication system,
A controller for performing a layer mapping on an input signal and performing preprocessing for mapping the layer mapped layer signal to an antenna port and performing a phase shift on the preprocessed antenna port signal;
And a transmitter for transmitting the signal processed by the controller to the terminal.
14. The apparatus of claim 13,
And controls applying a cyclic delay scaling factor for cyclic delay to the phase-shifted signal.
15. The method of claim 14, wherein the cyclic delay scaling factor comprises:
Wherein the base station is determined based on at least one of a number of antenna ports included in the base station and a channel state of a downlink channel.
The method as claimed in claim 15, wherein the channel status of the downlink channel includes:
Wherein the base station has the same frequency selectivity as the frequency selectivity of the uplink channel based on a sounding reference signal (SRS) received through an uplink channel.
14. The apparatus of claim 13,
And transmits a channel state indicator-reference signal (CSI-RS) including information on a physical channel through which the phase shifted signal is transmitted to the MS.
14. The apparatus of claim 13,
Determining a resource element for transmitting an effective channel for transmitting the phase shifted signal based on a frequency selectivity of an uplink channel, transmitting information on the resource element to the terminal, Wherein the control unit controls the transmitter to transmit information on the terminal to the terminal.
A terminal for processing a signal in a communication system,
Comprising: a receiver for receiving a signal from a base station;
And a control unit for controlling demodulation of the received signal,
Wherein the received signal is a signal obtained by performing a phase shift on the preprocessed antenna port signal after performing a preprocessing process of mapping the received signal to an antenna port of the base station.
20. The terminal of claim 19, wherein the received signal is a signal obtained by applying a cyclic delay scaling factor for cyclic delay to a signal that has undergone the phase shift by the base station.
21. The method of claim 20, wherein the cyclic delay scaling factor comprises:
The number of antenna ports included in the base station, and the channel state of the downlink channel.
22. The method of claim 21, wherein the channel status of the downlink channel is determined by:
Wherein the uplink channel has the same frequency selectivity as the frequency selectivity of the uplink channel based on a sounding reference signal (SRS) received through the uplink channel.
20. The apparatus of claim 19,
(CSI-RS) including information on a physical channel through which the phase shifted signal is transmitted from the base station, the control unit controls the base station to receive a CSI- And configuring an effective channel based on information on the available channel.
20. The apparatus of claim 19,
The base station controls to receive information on a determined resource element for transmitting an effective channel for transmitting the phase shifted signal based on a frequency selectivity of an uplink channel from the base station and receives information on the effective channel from the base station And configures an effective channel based on information on the resource element and information on the effective channel.

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