TW202040958A - Wireless communication device, channel estimating method thereof and wireless communication system - Google Patents

Abstract

A wireless communication device, a channel estimating method thereof and a wireless communication system are provided. A wireless communication device includes an interlayer interference detector configured to receive a reference signal including a plurality of layers transmitted through a plurality of ports respectively connected to a plurality of antennas and to determine whether interlayer interference occurs based on the reference signal; and a channel estimator configured to estimate a channel matrix by executing an algorithm that is based on whether the interlayer interference occurs. The wireless communication device may perform beamforming based on the estimated channel matrix.

Description

Wireless communication device, its channel estimation method and wireless communication system

The present disclosure generally relates to wireless communication devices, and more specifically, to wireless communication devices that perform channel estimation and a channel estimation method thereof.

In the wireless communication environment, the state of the wireless channel changes irregularly in the time domain and the frequency domain. The wireless communication device can perform channel estimation to determine the amount of distortion of the received signal received via the wireless channel, and can decode the received signal based on the estimated channel value to recover the transmitted signal data.

At the same time, corresponding to the long-term evolution (long term evolution, LTE) transmission mode or a fifth-generation (5 ^th Generation, 5G) agreement / proposal is published, the wireless communication device can be based on the reference signal relative to the target resource elements (target resource element) to perform channel estimation. Such reference signals can be transmitted from the base station to the wireless device on pre-designated subcarriers and time slots. The wireless device can then measure the amplitude and phase of the corresponding received signal at each of the multiple antenna elements of the wireless device to achieve "channel estimation" of the wireless channel condition. The received signal at each antenna element may be a composite signal having signal energy components received from both a line of site path and a scattered path. For example, in a multi-input-multi-output (MIMO) system, channel estimates can be dynamically fed back to the base station, and the base station can implement beamforming adjustments based on the channel estimates to improve or Optimize the communication link.

Embodiments of the inventive concept provide a wireless communication device and a channel estimation method of the wireless communication device. The wireless communication device is used to determine whether inter-layer interference occurs in multiple channels, and is used to determine whether inter-layer interference occurs or not. Use different algorithms to estimate the channel.

The embodiment also provides a wireless communication system for allowing the terminal to output a setting change request to the base station based on channel setting information received from the base station.

According to an aspect of the concept of the present invention, there is provided a wireless communication device, the wireless communication device includes an interlayer interference detector, the interlayer interference detector is configured to receive including transmission through multiple ports respectively connected to multiple antennas Based on the reference signal of multiple layers, it is judged whether inter-layer interference occurs based on the reference signal. The channel estimator can estimate the channel matrix by executing an algorithm based on whether the inter-layer interference occurs. The wireless communication device may perform beamforming based on the estimated channel matrix.

According to another aspect of the concept of the present invention, there is provided a channel estimation method for a wireless communication device. The method includes receiving a reference signal, the reference signal including multiple layers transmitted via multiple ports respectively connected to multiple antennas Relative to the reference signal to determine whether inter-layer interference occurs; when it is determined that the inter-layer interference does not occur, the channel is estimated by executing the first algorithm; and when it is determined that the inter-layer interference occurs, the execution is different from The second algorithm of the first algorithm estimates the channel.

According to another aspect of the concept of the present invention, a wireless communication system is provided, the wireless communication system includes: a base station configured to output reference signal setting information; and a terminal configured to determine based on the reference signal setting information Whether the current channel matrix is suitable for signal transmission and reception, and when the current channel matrix is not suitable for the signal transmission and reception, output a channel setting change request to the base station.

Hereinafter, the embodiments will be explained in detail with reference to the drawings.

FIG. 1 is a block diagram of a wireless communication system 1 according to an exemplary embodiment. The wireless communication system 1 may include a base station 20 and a terminal 10. The terminal 10 may be located in the cell coverage of the base station 20. The base station 20 and the terminal 10 can communicate with each other via the downlink channel 11 and the uplink channel 12. During communication via the downlink channel 11, the base station 20 and the terminal 10 can act as a wireless transmitter and a wireless receiver, respectively. During communication via the uplink channel 12, the base station 20 and the terminal 10 can act as a wireless receiver and a wireless transmitter, respectively.

The base station 20 can be a fixed station that communicates with the terminal 10 and/or another base station, and can transmit data and/or control information to the terminal 10 and/or another base station, and receive data from the terminal 10 and/or another base station. / Or control information. For example, the base station 20 may be called a node B, an evolved-node B (evolved-node B, eNB), a base transceiver system (base transceiver system, BTS), or an access point (access point, AP). The terminal 10 may be any of various wireless communication devices that can transmit data and/or control information to the base station 20 and receive data and/or control information from the base station 20. For example, the terminal 10 may be referred to as user equipment (UE), mobile station (MS), mobile terminal (MT), user terminal (UT), user station (Subscriber station, SS), wireless device or portable device.

The wireless communication network between the base station 20 and the terminal 10 can support communication between multiple users by sharing available network resources. For example, information can be transmitted via wireless communication networks in the following various modes: code division multiple access (CDMA) mode, frequency division multiple access (FDMA) mode, and time division multiple access (FDMA) mode. Take (time division multiple access, TDMA) mode, orthogonal frequency division multiple access (orthogonal FDMA, OFDMA) mode and single carrier frequency division multiple access (single carrier FDMA, SC-FDMA) mode.

The term "layer" used in this text refers to a signal of an independent data stream transmitted to a receiving device using a corresponding set of antenna resources, as in a multiple input multiple output system. For example, in a polarization diversity scheme, one or more first antenna elements can transmit a first data stream of a first layer with a first polarization, and one or more second days The line element can emit a signal of the second data stream of the second layer with the second orthogonal polarization. The receiving device may use different antennas to receive the first data stream and the second data stream, and the different antennas are configured to receive signals arriving with different polarizations. The first data stream and the second data stream may be component data streams of a common communication session, thereby increasing the data throughput of the communication session. In another example, the first antenna element may form a beam directed in the first direction to transmit the first layer, and the second antenna element may form a beam directed in the second direction to transmit the second layer. In yet another example, the same set of antenna elements can be used to transmit different layers by using different analog beamforming networks, each of which is coupled to the set of antenna elements , But produce different phase relations between antenna elements to form beams pointing in different directions. In this case, the first beamforming network can be used to use the first beam pointing in the first direction to transmit the first data stream through the antenna element, and the second beamforming network can be used to use the second beam pointing in the second direction. The beam simultaneously transmits the second data stream through the same antenna element. Such beamforming using different layers to transmit data streams can occur on the receiving side as well as on the transmitting side.

The term "antenna port" (for brevity, interchangeably referred to as "port") as used in this article refers to an antenna element.

The base station 20 can transmit a downlink signal including data to the terminal 10 via at least one antenna port. The base station 20 can perform multi-layer transmission through multiple antenna ports at the base station 20 and multiple antenna ports at the terminal 10. The base station 20 may transmit the reference signal RS (which may include multiple symbols) to the terminal 10 via the downlink channel 11. In the OFDM scheme, the reference signal RS that can be transmitted in the allocated time slot may include multiple symbols simultaneously or sequentially transmitted through different subcarriers. Each subcarrier can carry a symbol or a sequence of symbols in the allocated time slot. According to an embodiment, the base station 20 may use multiple input multiple output (MIMO) communication to transmit the reference signal RS. As understood from the discussion of "layers" above, MIMO communication can refer to communication using multiple antennas via multiple layers.

Now, the reference signal RS is a signal used to estimate the channel of the data signal, and can be called a pilot. In the uplink direction, the reference signal RS may be a demodulation reference signal (DM-RS) (as specified in the LTE/5G agreement/proposal), which is used for channel estimation in a certain terminal. In the downlink direction, the reference signal RS may include a common reference signal (CRS) and/or a channel state information reference signal (CSI-RS) (both are in the LTE/5G protocol) /Specified in the proposal). Alternatively, other types of signals can be used for the reference signal RS. In the following, it is assumed that the reference signal RS is a downlink reference signal.

The terminal 10 may include an inter-layer interference detector 130 and a channel estimator 140. Each element included in the terminal 10 may be implemented as a hardware block including an analog circuit and/or a digital circuit or a processing circuit that executes a software block including a plurality of instructions.

The inter-layer interference detector 130 can determine whether inter-layer interference occurs relative to the reference signal RS transmitted through multiple layers. In this article, the phrase "determine whether inter-layer interference occurs" or similar phrases is to determine whether the inter-layer interference is higher than a threshold or exhibit certain characteristics according to a predefined standard. Examples of these are discussed below. The method performed by the inter-layer interference detector 130 to determine whether inter-layer interference occurs will be described in detail with reference to FIGS. 6 to 8.

The inter-layer interference detector 130 may output information indicating whether inter-layer interference occurs with respect to the reference signal RS to the channel estimator 140, and the channel estimator 140 may estimate the receiving channel based on whether the inter-layer interference occurs.

According to the embodiment, since the terminal 10 determines whether inter-layer interference occurs with respect to the reference signal RS and estimates the receiving channel based on whether inter-layer interference occurs, it can efficiently estimate the channel suitable for signal transmission and reception despite the existence of inter-layer interference. And after that, data transmission and reception can be performed smoothly. For example, the beamforming performed by the base station 20 and/or the wireless device 10 may be adjusted based on the estimated channel matrix. Alternatively or additionally, the result of the estimated channel matrix can be used to determine whether to maintain the current number of layers used to exchange data between the base station 20 and the wireless device 10.

The terminal 10 can determine whether the current channel setting is appropriate based on the reference signal RS, and can provide the channel setting change request CCR to the base station 20 via the uplink channel 12. The base station 20 can output the reference signal RS based on the changed setting to the terminal 10 in response to the channel setting change request CCR. For example, the base station 20 may change the allocated subcarriers and/or time slots of the reference signal RS based on the channel setting change request CCR.

According to the embodiment, the terminal 10 can judge whether the current channel setting is appropriate, and can provide the channel setting change request CCR to the base station 20 based on the judgment result, and therefore, can achieve smooth data transmission and reception suitable for the base station 20 and the terminal 10 Channel settings.

2 is a block diagram of a wireless communication device (“wireless device” or simply “device” for brevity) 100 according to an exemplary embodiment. The wireless device 100 may be any type of device that receives signals via a wireless network, and is an example of the terminal 10 in FIG. 1.

As shown in FIG. 2, the wireless device 100 may include a reception (RX) filter 110, a synchronization block 120, an inter-layer interference detector 130, a channel estimator 140, a demodulation block 150, and a decoding block 160.

The receiving filter 110 can filter the downlink signal received from the antenna port AP of the base station so as to pass only the signal of the desired frequency. The receiving filter 110 can also convert the received signal into a digital signal.

In the case of initial access to the cell, when the terminal performs handover or cell reselection from the current cell to another cell, the synchronization block 120 may use the synchronization signal included in the filtered downlink signal (for example, , Primary synchronous signal (PSS) and secondary synchronous signal (SSS) are used to perform cell search, and the frequency and symbol synchronization relative to the cell can be obtained by cell search using the synchronous signal. The synchronization block 120 can also obtain the downlink frame synchronization of the cell and determine a cell identifier (ID).

The interlayer interference detector 130 can measure the interlayer interference relative to the reference signal transmitted from the antenna port AP of the base station 20, and can output a signal indicating whether interlayer interference occurs to the channel estimator 140 based on the measurement result.

The channel estimator 140 may select an algorithm for estimating the receiving channel of the reference signal based on whether inter-layer interference occurs. In an embodiment, when inter-layer interference does not occur, the channel estimator 140 may not separate the results of the frequency channels of the layers (for example, it may instead perform averaging the results of different subcarriers and use the averaging result), and A first algorithm may be used to estimate the receiving channel, which estimates the receiving channel based on the variance of the noise in the reference signal. In an embodiment, the first algorithm may include the following equations (1) and (2), where equation (1) may include the signal filter parameters according to the first algorithm:

方程式（1）

Equation (1)

為根據第一演算法的訊號濾波器，且

為對應於接收的參考訊號的第i埠的通道向量。此外，

為估計目標通道，

分別為

及

的互相關（cross-correlation）以及

的自相關（auto-correlation），且

為雜訊的變化。

為對應於估計目標通道的正交覆蓋碼矩陣，I為單位矩陣，並且()^-1為反函數。

方程式（2）Here,

Is a signal filter based on the first algorithm, and

Is the channel vector of the i-th port corresponding to the received reference signal. In addition,

To estimate the target channel,

Respectively

and

The cross-correlation and

Auto-correlation, and

Is the change of noise.

Is the orthogonal cover code matrix corresponding to the estimation target channel, I is the identity matrix, and ()^-1 is the inverse function.

Equation (2)

為接收訊號，且

為估計接收通道。接收訊號Y可包括與多個層相關聯的項及雜訊項。among them

To receive the signal, and

To estimate the receiving channel. The received signal Y may include items associated with multiple layers and noise items.

In an embodiment, when inter-layer interference occurs, the channel estimator 140 can use a second algorithm that takes into account the inter-layer interference to estimate the receiving channel, where the second algorithm can separate the measurement results of the frequency channels of the two layers from each other. To estimate the receiving channel.

方程式（3）In an embodiment, the second algorithm may include the following equations (3) and (4), where equation (3) may consider inter-layer interference to define a signal filter:

Equation (3)

為根據第二演算法的訊號濾波器，

為對應於接收的參考訊號的第i埠的通道向量，並且

為接收參考訊號的兩個埠的正交覆蓋碼矩陣。此外，

為估計目標通道，

分別為

及

的互相關及

的自相關，且

為雜訊的變化，其中「n」為所估計目標通道的通道號。當使用方程式（3）確定層間干擾濾波器時，可使用方程式（4）來估計接收通道：

方程式（4）Here,

Is the signal filter based on the second algorithm,

Is the channel vector of the i-th port corresponding to the received reference signal, and

It is the orthogonal cover code matrix of the two ports receiving the reference signal. In addition,

To estimate the target channel,

Respectively

and

Cross-correlation and

Autocorrelation, and

Is the change of noise, where "n" is the channel number of the estimated target channel. When using equation (3) to determine the inter-layer interference filter, equation (4) can be used to estimate the receiving channel:

Equation (4)

為接收訊號，且

為估計接收通道。Here,

To receive the signal, and

To estimate the receiving channel.

The demodulation block 150 can use downlink channel estimation to detect the data signal and modulate the detection value. The operation of detecting the data signal may include using the estimated channel value corresponding to the resource element to which the data signal is mapped to obtain the estimated data signal. The decoding block 160 can obtain the data signal transmitted from the base station to the terminal by descrambling and decoding the modulated data signal.

In an embodiment, the wireless communication device 100 may further include a terminal status information generator. The terminal status information generator can generate channel status information, and the channel status information can be calculated based on the terminal's moving speed information and/or the terminal's multipath channel delay information. The terminal status information generator can measure the current moving speed of the terminal within the cell area of the base station 20 in FIG. 1, and can generate moving speed information from this. Additionally or alternatively, the terminal status information generator generates multipath channel delay information on the downlink signal, which is received by the current terminal via other base stations or repeaters, or after being reflected from objects such as buildings Was received. The terminal status information generator can periodically or non-periodically generate channel status information and provide the channel status information to the base station 20 in FIG. 1.

The wireless communication device 100 is illustrated with reference to FIG. 2, but other configurations can be used instead in alternative embodiments. The wireless communication device 100 may have various configurations according to various communication protocols.

3A and 3B are diagrams for explaining a channel estimation method according to an exemplary embodiment. The channel estimation methods in FIGS. 3A and 3B can be executed by the wireless communication device 100 in FIG. 2.

2 and 3A, the horizontal axis is time, and the vertical axis is frequency. The number on the horizontal axis can represent the symbol slot, and the number on the vertical axis can represent the subcarrier index. The first layer LAYER1 can correspond to the signal transmitted using the first set of antenna resources (first antenna element and/or the first beamforming network) at the base station, and the second layer LAYER2 can correspond to the second set of antenna resources at the base station. The signal received by the group antenna resource. The subframe corresponding to a single layer may include 14 symbols in the time domain and 12 subcarriers in the frequency domain.

To perform channel estimation, the base station 20 in FIG. 1 can transmit a reference signal RS at a predetermined time-frequency position ("resource element") in each downlink subframe via multiple layers, and can transmit a reference signal RS via other time -The frequency position transmits the data signal. Some data signals can be signals corresponding to various types of physical channels.

3A, the reference signal RS can be assigned (or "mapped") to resource elements corresponding to subcarrier indexes 2, 5, 8, and 11, and symbol slots 2, 5, 8, and 11. In an embodiment, the reference signal RS is composed of a first layer reference signal RS1 and a second layer reference signal RS2, wherein the signal RS1 and the signal RS2 can be transmitted simultaneously in one embodiment, or sequentially in an alternative embodiment. The first layer reference signal RS1 is composed of four reference signals of different subcarriers: a first reference signal RS1_1, a second reference signal RS1_2, a reference signal RS1_3, and a reference signal RS1_4. The second layer reference signal RS2 can also be composed of four reference signals of different subcarriers: the third reference signal RS2_1, the fourth reference signal RS2_2, the reference signal RS2_3, and the reference signal RS3_4. All the subcarriers of the first layer reference signal RS1 can be transmitted from the first antenna port of the base station, and all the subcarriers of the second layer reference signal RS2 can be transmitted from the second antenna port of the base station. The first reference signal RS1_1 can be mapped to resource elements corresponding to subcarrier index 11 and symbol slot 2, and the second reference signal RS1_2 can be mapped to resource elements corresponding to subcarrier index 8 and symbol slot 2. The third reference signal RS2_1 can be mapped to the same resource element as the first reference signal RS1_1 but transmitted from the second antenna port, and the fourth reference signal RS2_2 can be mapped to the same resource element as the second reference signal RS1_2 but from the The second antenna port transmits.

Since the first reference signal RS1_1 and the third reference signal RS2_1 or the second reference signal RS1_2 and the fourth reference signal RS2_2 are transmitted from different antenna ports but use the same resource elements, inter-layer interference may occur between signals of different layers.

According to an embodiment, the wireless communication device can determine whether interference between multiple layers has occurred, and can remove the interference between the layers by separating the results of the frequency channels of the two layers from each other, thereby increasing the receiving channel (where each The frequency channel corresponds to the respective subcarrier) estimation accuracy.

Referring to FIG. 3B, the reference signal RS can be assigned as another option to resource elements corresponding to subcarrier indexes 2, 5, 8, and 11 and symbol indexes 2, 3, 8, and 9. Although the element type used for arranging the reference signal RS in FIG. 3B is different from the element type in FIG. 3A, inter-layer interference may still occur, and the embodiment can be applied to the case of FIG. 3B.

In this specification, the standard for arranging the reference signal as shown in FIG. 3A or FIG. 3B may be referred to as a channel pattern. In other words, the standard shown in FIG. 3A may be referred to as the first channel type, and the standard shown in FIG. 3B may be referred to as the second channel type.

3A and 3B only show examples of the arrangement of reference signals, and the number and arrangement of the reference signals in a single subframe can vary with one or more antenna ports, transmission modes, etc. through which the subframe is transmitted .

Fig. 4 is a flowchart of a channel estimation method according to an exemplary embodiment.

2 and 4, in operation S11, the wireless communication device 100 may receive the reference signal through multiple layers. In operation S21, the wireless communication device 100 can determine whether inter-layer interference occurs relative to the reference signal.

When the inter-layer interference does not occur in operation S31, in operation S41, the wireless communication device 100 may not separate the results of the frequency channels of the two layers from each other, and may estimate the reception channel. In an embodiment, the wireless communication device 100 may use the first algorithm including equation (1) and equation (2) described above with reference to FIG. 2 to estimate the receiving channel.

In addition, when inter-layer interference occurs in operation S31, the wireless communication device 100 may take the inter-layer interference into consideration in operation S51 to estimate the receiving channel by separating the results of the frequency channels of the two layers from each other. In an embodiment, the wireless communication device 100 may use the second algorithm including equation (3) and equation (4) described above with reference to FIG. 2 to estimate the receiving channel.

FIG. 5 is a block diagram of the inter-layer interference detector 130 according to an exemplary embodiment. The inter-layer interference detector 130 may include an arithmetic calculator 131 and an inter-layer interference determiner 132. The arithmetic calculator 131 may receive the reference signal RS, generate a calculation result CR by applying the reference signal RS to a predetermined formula, and output the calculation result CR to the inter-layer interference determiner 132. The inter-layer interference determiner 132 may compare the calculation result CR with a predetermined reference value to determine whether inter-layer interference occurs, and output the inter-layer interference measurement signal IID to the channel estimator 140 in FIG. 2. In an embodiment, the inter-layer interference measurement signal IID may include information indicating the selected algorithm (for example, the first algorithm or the second algorithm described with reference to FIG. 2) used to estimate the channel.

方程式（5）In an embodiment, the reference signal RS may include a first frequency channel reception signal (for example, the first reference signal RS1_1 in FIG. 3A) received via a first frequency channel (for example, the subcarrier index 11 in FIG. 3A) and via The second frequency channel reception signal (for example, the second reference signal RS1_2 in FIG. 3A) received by the second frequency channel (for example, subcarrier index 8 in FIG. 3A), and the arithmetic calculator 131 can compare with the first frequency channel The corresponding first channel vector and the second channel vector corresponding to the second frequency channel perform correlation, and generate a correlation value as a calculation result. The inter-layer interference determiner 132 may compare the correlation value with the first reference value, and when the correlation value is less than the first reference value, determine that inter-layer interference occurs. In an embodiment, the inter-layer interference detector 130 can use equation (5) to determine whether inter-layer interference occurs:

Equation (5)

為第一通道向量，

為第二通道向量，並且

為第一參考值。Cor()表示兩個函數的相關性。among them

Is the first channel vector,

Is the second channel vector, and

Is the first reference value. Cor() represents the correlation of two functions.

方程式（6）In an embodiment, the arithmetic calculator 131 may obtain the maximum delay spread of the reference signal RS as the calculation result, and the inter-layer interference determiner 132 may compare the maximum delay spread with the second reference value, and when the maximum delay spread is greater than the second reference value Value, it is determined that inter-layer interference occurs. In an embodiment, the inter-layer interference detector 130 can use equation (6) to determine whether inter-layer interference occurs:

Equation (6)

為參考訊號RS的最大延遲擴展，並且

為第二參考值。among them

Is the maximum delay spread of the reference signal RS, and

It is the second reference value.

In an embodiment, the reference signal RS may include a first frequency channel reception signal (for example, the first reference signal RS1_1 in FIG. 3A) received via a first frequency channel (for example, the subcarrier index 11 in FIG. 3A) and via The second frequency channel reception signal (for example, the second reference signal RS1_2 in FIG. 3A) received by the second frequency channel (for example, subcarrier index 8 in FIG. 3A), and the arithmetic calculator 131 may receive signals based on the first frequency channel The difference between the signal and the signal received by the second frequency channel is used to generate an interference metric, the interference metric is normalized, and a normalized value is generated as a calculation result. The inter-layer interference determiner 132 may compare the normalized value with a third reference value, and determine that inter-layer interference occurs when the normalized value is greater than the third reference value. In an embodiment, the third reference value may be generated based on the variance of the noise that occurs when the reference signal RS is received.

In an embodiment, the interference metric Z can be defined according to equation (7):

方程式（7）

Equation (7)

為第一通道接收訊號，且

為第二通道接收訊號。利用此結果，層間干擾偵測器130可使用方程式（8）來判斷是否發生層間干擾：

方程式（8）among them

Receive the signal for the first channel, and

Receive signal for the second channel. Using this result, the inter-layer interference detector 130 can use equation (8) to determine whether inter-layer interference occurs:

Equation (8)

為第三參考值。E()代表Z的正規化均值函數。among them

It is the third reference value. E() represents the normalized mean function of Z.

Fig. 6 is a flowchart of a method for determining whether inter-layer interference occurs according to an exemplary embodiment. In detail, FIG. 6 may show an example of operation S21 in FIG. 4. The explanations already made with reference to FIG. 5 will not be repeated.

5 and 6, in operation S110, the inter-layer interference detector 130 may calculate the correlation value by performing correlation on the first channel vector and the second channel vector. In an embodiment, the first channel vector and the second channel vector can be obtained empirically with respect to the corresponding frequency channel. In operation S120, the inter-layer interference detector 130 may compare the correlation value with a predetermined first reference value.

When the correlation value is not less than the first reference value, in operation S130, the inter-layer interference detector 130 may output a first signal (for example, IID=0) indicating that no inter-layer interference occurs to the channel estimator 140 in FIG. 2 . When the correlation value is less than the first reference value, in operation S140, the inter-layer interference detector 130 may output a second signal (for example, IID=1) indicating that inter-layer interference occurs to the channel estimator 140 in FIG. 2.

Fig. 7 is a flowchart of a method for determining whether inter-layer interference occurs according to an exemplary embodiment. In detail, FIG. 7 may show another example of operation S21 in FIG. 4. The explanations already made with reference to FIG. 5 will not be repeated.

5 and 7, in operation S210, the inter-layer interference detector 130 can obtain the maximum delay spread of the reference signal RS. In an embodiment, the reference signal RS may include information about the maximum delay spread, and the inter-layer interference detector 130 may use the information to obtain the maximum delay spread. Alternatively, the inter-layer interference detector 130 can obtain the maximum delay spread by applying the reference signal RS to a predetermined algorithm. In operation S220, the inter-layer interference detector 130 may compare the maximum delay spread with a predetermined second reference value.

When the maximum delay spread is not greater than the second reference value, in operation S230, the inter-layer interference detector 130 may output a first signal (for example, IID=0) indicating that no inter-layer interference occurs to the channel estimator in FIG. 2 140. When the maximum delay spread is greater than the second reference value, in operation S240, the inter-layer interference detector 130 may output a second signal (for example, IID=1) indicating that inter-layer interference occurs to the channel estimator 140 in FIG. 2.

Fig. 8 is a flowchart of a method for determining whether inter-layer interference occurs according to an exemplary embodiment. In detail, FIG. 8 may show another example of operation S21 in FIG. 4. The explanations already made with reference to FIG. 5 will not be repeated.

5 and 8, in operation S310, the inter-layer interference detector 130 may generate an interference metric based on the difference between the received signal of the first frequency channel and the received signal of the second frequency channel. In operation S320, the inter-layer interference detector 130 may compare the normalized value of the interference metric with a third reference value.

When the normalized value is not greater than the third reference value, in operation S330, the inter-layer interference detector 130 may output a first signal (for example, IID=0) indicating that no inter-layer interference occurs to the channel estimator in FIG. 2 140. When the normalized value is greater than the third reference value, in operation S340, the inter-layer interference detector 130 may output a second signal (for example, IID=1) indicating that inter-layer interference occurs to the channel estimator 140 in FIG. 2.

FIG. 9 is a block diagram of an inter-layer interference detector according to an exemplary embodiment.

9, the inter-layer interference detector 130 may include an arithmetic calculator 131, an inter-layer interference determiner 132, and a similarity determiner 133. The arithmetic calculator 131 and the inter-layer interference determiner 132 have been described above with reference to FIG. 5, and therefore they will not be described again.

The similarity determiner 133 can receive the reference signal RS including the first port reception signal PRS1 and the second port reception signal PRS2, and can determine the sequence of the first port reception signal PRS1 and the second port reception based on the interlayer interference measurement signal IID The similarity between the sequences of the signal PRS2. In an embodiment, the sequence may refer to a data sequence of each of the first port reception signal PRS1 and the second port reception signal PRS2.

方程式（9）In an embodiment, the similarity determiner 133 may determine the similarity based on the interference metric. The interference metric Z(n) can be defined according to equation (9):

Equation (9)

及第四參考值

滿足以下方程式（10）時，相似性判斷器133可確定第一埠接收訊號PRS1類似於第二埠接收訊號PRS2：When the interference correlation value

And the fourth reference value

When the following equation (10) is satisfied, the similarity determiner 133 can determine that the received signal PRS1 at the first port is similar to the received signal PRS2 at the second port:

方程式（10）

Equation (10)

：The interference related value can be defined according to equation (11)

:

方程式（11）

Equation (11)

Where E() represents the mean value function.

When the first port reception signal PRS1 is similar to the second port reception signal PRS2, the similarity determiner 133 may output the determination signal EA to the channel estimator 140 in FIG. 2, and the channel estimator 140 may use different values based on the determination signal EA. Algorithm to estimate the receiving channel. This will be described in detail below with reference to FIG. 10.

Fig. 10 is a flowchart of a channel estimation method according to an exemplary embodiment. The explanations already made with reference to FIG. 4 will not be repeated.

2, 4 and 10, in operation S12, the wireless communication device 100 may receive a reference signal through multiple layers, and the reference signal includes a first port reception signal and a second port reception signal. In operation S22, the wireless communication device 100 can determine whether inter-layer interference occurs relative to the reference signal. The operation S22 of determining whether inter-layer interference occurs may be the same as or similar to the operation S21 in FIG. 4, and therefore it will not be described in detail.

When the inter-layer interference does not occur in operation S32, in operation S42, the wireless communication device 100 may estimate the reception channel without separating the results of the frequency channels of the two layers from each other. The operation S42 in which the result of estimating the receiving channel without separating the frequency channels of the two layers may be the same as or similar to the first algorithm set forth in the operation S41 of FIG. 4, and therefore it will not be described in detail.

When inter-layer interference occurs in operation S32, in operation S52, the wireless communication device 100 may calculate an interference correlation value indicating the difference between the sequence of the first port receiving signal PRS1 and the sequence of the second port receiving signal PRS2 The similarity. The method of calculating the interference correlation value is the same as the method explained above with reference to FIG. 9.

When the interference correlation value is greater than the predetermined fourth reference value, in operation S82, the wireless communication device 100 may separate the frequency channels of the two layers from each other and estimate the receiving channel. The operation S82 of separating the frequency channels of the two layers from each other and estimating the receiving channel may be the same as or similar to the second algorithm described in operation S51 of FIG. 4, and therefore, it will not be described in detail.

方程式（12）When the interference correlation value is not greater than the fourth reference value, in operation S72, the wireless communication device 100 may estimate the receiving channel in consideration of the variance of the interference metric. In an embodiment, the wireless communication device 100 may use a third algorithm that considers the variance of the interference metric to estimate the receiving channel. The third algorithm may include the following equation (12) and equation (13). Specifically, equation (12) is about a signal filter that considers the variance of interference metrics.

Equation (12)

為根據第三演算法的訊號濾波器，並且

為對應於接收的參考訊號的第i埠的通道向量。此外，

為估計目標通道，

分別為

及

的互相關及

的自相關，

為雜訊的變化，且

為在方程式（9）中闡述的干擾度量的變異數。當使用方程式（12）判斷層間干擾濾波器時，可使用方程式（13）來估計接收通道：

方程式（13）Here,

Is a signal filter based on the third algorithm, and

Is the channel vector of the i-th port corresponding to the received reference signal. In addition,

To estimate the target channel,

Respectively

and

Cross-correlation and

Autocorrelation,

Is the change in noise, and

Is the variance of the interference metric stated in equation (9). When using equation (12) to determine the inter-layer interference filter, equation (13) can be used to estimate the receiving channel:

Equation (13)

為接收訊號，且

為所估計的接收通道。among them

To receive the signal, and

Is the estimated receiving channel.

FIG. 11 is a diagram illustrating a method of operating a wireless communication system according to an exemplary embodiment. In detail, FIG. 11 shows an embodiment in which the terminal outputs a channel setting change request.

Referring to FIG. 11, the wireless communication system may include a base station 20 and a terminal (or UE) 10. In operation T110, the base station 20 can output the reference signal setting information to the terminal 10. In operation T120, the terminal 10 can determine whether the receiving channel is suitable for signal transmission and reception based on the reference signal setting information. In an embodiment, the terminal 10 may determine whether the receiving channel is suitable for signal transmission and reception based on the following: Doppler spread, Doppler shift, average delay, delay spread , The data traffic pattern and/or the receiving performance of the terminal 10.

When the receiving channel is not suitable for signal transmission and reception, in operation T130, the terminal 10 may output a channel setting change request to the base station 20. In operation T140, the base station 20 may change the channel setting in response to the channel setting change request, and use the changed channel setting to output the reference signal. In an embodiment, the base station 20 can change the channel type in response to the channel setting change request. In an embodiment, the base station 20 can change the first channel type shown in FIG. 3A to the second channel type shown in FIG. 3B in response to the channel setting change request, and vice versa.

According to the embodiment, the terminal 10 can determine whether the receiving channel is suitable for signal transmission and reception, and output a channel setting change request based on the judgment result, and therefore, the terminal 10 and the base station 20 can efficiently find a channel setting suitable for signal transmission and reception , And can perform signal transmission and reception smoothly.

FIG. 12 is a diagram illustrating a method of operating a wireless communication system according to an exemplary embodiment. In detail, FIG. 12 shows an embodiment in which the terminal outputs changed channel setting information. The explanation made with reference to FIG. 11 will not be repeated.

Referring to FIG. 12, the wireless communication system may include a base station 20 and a terminal (or UE) 10. In operation T210, the base station 20 may output the reference signal setting information to the terminal 10. In operation T220, the terminal 10 can determine whether the receiving channel is suitable for signal transmission and reception based on the reference signal setting information. When the receiving channel is not suitable for signal transmission and reception, in operation T230, the terminal 10 can output the changed channel setting information to the base station 20. In an embodiment, the changed channel setting information may include information about the channel type. In operation T240, the base station 20 may change the channel setting according to the channel type included in the changed channel setting information, and use the changed channel setting to output the reference signal.

FIG. 13 is a block diagram of a wireless communication device 1000 according to an exemplary embodiment. 13, the wireless communication device 1000 may include an application specific integrated circuit (ASIC) 1100, an application specific instruction set processor (ASIP) 1300, a memory 1500, and a main processor 1700. And main memory 1900. At least two of the ASIC 1100, the ASIP 1300, and the main processor 1700 can communicate with each other. In addition, at least two of the ASIC 1100, the ASIP 1300, the memory 1500, the main processor 1700, and the main memory 1900 may be embedded in a single chip.

The ASIC 1100 is customized for a specific purpose, and may include a radio-frequency integrated circuit (RFIC), a modulator, a demodulator, and the like. ASIP 1300 can support an instruction set dedicated to a specific application, and can execute instructions included in the instruction set. As a non-transitory storage device, the memory 1500 can communicate with the ASIP 1300 and can store multiple commands executed by the ASIP 1300. The memory 1500 can also store data generated when executing commands in the ASIP 1300. For example, the memory 1500 may include random access memory (RAM), read-only memory (ROM), magnetic tape, magnetic disk, optical disc, volatile memory, and non-volatile memory. Memory and/or its combination. In addition to the above, the memory 1500 may also include any type of memory that can be accessed by the ASIP 1300.

The main processor 1700 can control the wireless communication device 1000, such as a user equipment (UE), by executing instructions. For example, the main processor 1700 can control the ASIC 1100 and the ASIP 1300, and can process data received via a wireless communication network or user input to the wireless communication device 1000. As a non-transitory storage device, the main memory 1900 can communicate with the main processor 1700 and can store multiple instructions executed by the main processor 1700. For example, the main memory 1900 may include any type of memory accessible by the main processor 1700, such as RAM, ROM, tape, magnetic disk, optical disk, volatile memory, non-volatile memory, or a combination thereof.

According to the above-mentioned embodiment, the components of the wireless communication device (for example, the terminal 10 in FIG. 1 or the wireless communication device 100 in FIG. 2) or the operations included in the channel estimation method thereof may be included in the wireless communication device 1000 shown in FIG. At least one element. For example, at least one selected from the inter-layer interference detector 130 and the channel estimator 140 may be implemented by a plurality of instructions stored in the memory 1500. In an embodiment, at least one operation in the channel estimation method of FIG. 4 may be implemented by a plurality of instructions stored in the memory 1500.

When the ASIP 1300 executes a plurality of instructions stored in the memory 1500, at least one operation selected from at least one of the inter-layer interference detector 130 and the channel estimator 140 or the channel estimation method can be performed. In another embodiment, at least one selected from the inter-layer interference detector 130 and the channel estimator 140 in FIG. 1 or at least one operation in the channel estimation method may be implemented by a hardware block included in the ASIC 1100 . In yet another embodiment, at least one selected from the inter-layer interference detector 130 and the channel estimator 140 in FIG. 1 or at least one operation in the channel estimation method can be performed by a plurality of instructions stored in the main memory 1900 To implement. When the main processor 1700 executes the instructions stored in the main memory 1900, at least one operation of the inter-layer interference detector 130 and/or the channel estimator 140 or the channel estimation method can be performed.

Although the inventive concept has been specifically illustrated and described with reference to the embodiments of the inventive concept, it should be understood that various changes in form and details can be made without departing from the spirit and scope of the scope of the following patent applications.

1: Wireless communication system 10: terminal 11: Downlink channel 12: Uplink channel 20: base station 100: Wireless communication device/wireless device 110: Receive (RX) filter 120: sync block 130: Interlayer interference detector 131: Arithmetic Calculator 132: Interlayer interference determiner 133: Similarity Determiner 140: Channel Estimator 150: Demodulation block 160: decode block 1000: wireless communication equipment 1100: Application-specific integrated circuit (ASIC) 1300: Application Specific Instruction Set Processor (ASIP) 1500: memory 1700: main processor 1900: main memory AP: Antenna port CCR: Channel setting change request CR: calculation result EA: Judgment signal IID: Interlayer interference measurement signal LAYER1: first layer LAYER2: second layer PRS1: The first port to receive the signal PRS2: The second port receives the signal RS: Reference signal RS1: first layer reference signal RS1_1: The first reference signal RS1_2: The second reference signal RS1_3, RS1_4: Reference signal RS2: The second layer reference signal RS2_1: third reference signal RS2_2: The fourth reference signal RS2_3, RS2_4: reference signal S11, S12, S21, S22, S31, S32, S41, S42, S51, S52, S62, S72, S82: Operation S110, S120, S130, S140, S210, S220, S230, S240, S310, S320, S330, S340: Operation T110, T120, T130, T140, T210, T220, T230, T240: Operation

The embodiments of the inventive concept will be understood more clearly by reading the following detailed description in conjunction with the drawings. In the drawings, the same reference characters indicate the same elements or features. In the drawings: Fig. 1 is a block diagram of a wireless communication system according to an exemplary embodiment. Fig. 2 is a detailed block diagram of a wireless communication device according to an exemplary embodiment. 3A and 3B are diagrams for explaining a channel estimation method according to an exemplary embodiment. Fig. 4 is a flowchart of a channel estimation method according to an exemplary embodiment. FIG. 5 is a block diagram of an inter-layer interference detector according to an exemplary embodiment. Fig. 6 is a flowchart of a method for determining whether inter-layer interference occurs according to an exemplary embodiment. Fig. 7 is a flowchart of a method for determining whether inter-layer interference occurs according to an exemplary embodiment. Fig. 8 is a flowchart of a method for determining whether inter-layer interference occurs according to an exemplary embodiment. FIG. 9 is a block diagram of an inter-layer interference detector according to an exemplary embodiment. Fig. 10 is a flowchart of a channel estimation method according to an exemplary embodiment. FIG. 11 is a diagram illustrating a method of operating a wireless communication system according to an exemplary embodiment. FIG. 12 is a diagram illustrating a method of operating a wireless communication system according to an exemplary embodiment. FIG. 13 is a block diagram of a wireless communication device according to an exemplary embodiment.

1: Wireless communication system

10: terminal

11: Downlink channel

12: Uplink channel

20: base station

130: Interlayer interference detector

140: Channel Estimator

CCR: Channel setting change request

RS: Reference signal

Claims (25)

A wireless communication device includes: The interlayer interference detector is configured to receive reference signals including multiple layers transmitted through multiple ports respectively connected to multiple antennas, and determine whether interlayer interference occurs based on the reference signals; and The channel estimator is configured to estimate the channel matrix by executing an algorithm based on whether the inter-layer interference occurs, The wireless communication device is configured to decode the received signal based on the estimated channel matrix. The wireless communication device according to claim 1, wherein When the inter-layer interference does not occur, the channel estimator estimates the channel matrix based on the variance of the noise in the reference signal, and does not compare the measurement results of the different frequency channels of the multiple layers to each other. Separate; and When the inter-layer interference occurs, the channel estimator separates the measurement result, and estimates the channel matrix based on the separated measurement result. The wireless communication device according to claim 1, The reference signal is received via a first frequency channel and a second frequency channel with different carriers, and The interlayer interference detector: Obtaining a correlation value by performing correlation on a first channel matrix corresponding to the first frequency channel and a second channel matrix corresponding to the second frequency channel, and Determine whether the inter-layer interference occurs based on the correlation value and the first reference value. The wireless communication device according to claim 1, wherein the inter-layer interference detector obtains the maximum delay spread of the reference signal, and determines whether the inter-layer interference occurs based on the maximum delay spread and a second reference value. The wireless communication device according to claim 1, The reference signal is received via a first frequency channel and a second frequency channel with different carriers, and The inter-layer interference detector generates an interference metric based on the difference between the first frequency channel reception signal received via the first frequency channel and the second frequency channel reception signal received via the second frequency channel, and based on all The normalized value of the interference metric and the third reference value determine whether the inter-layer interference occurs. The wireless communication device according to claim 1, The plurality of ports include a first port connected to a first antenna and a second port connected to a second antenna, and the reference signal includes a first port received signal received through the first port and a The second port receiving signal received by the second port, The interlayer interference detector generates an interference correlation value, the interference correlation value indicating the similarity between the data sequence of the signal received at the first port and the data sequence of the signal received at the second port, and The channel estimator estimates the channel matrix by executing the algorithm based on whether the inter-layer interference occurs and the interference correlation value. The wireless communication device according to claim 6, wherein When the inter-layer interference does not occur, the channel estimator estimates the channel matrix based on the variance of the noise in the reference signal, without separating the results of the different frequency channels of the multiple layers from each other ； When the inter-layer interference occurs and the interference correlation value is greater than a fourth reference value, the channel estimator separates the results of the frequency channels of the multiple layers, and estimates the results based on the separated results Said channel matrix; and When the inter-layer interference occurs and the interference correlation value is not greater than the fourth reference value, the channel estimator is based on the difference between the received signal at the first port and the received signal at the second port The variance of the interference metric is used to estimate the channel matrix. A channel estimation method for a wireless communication device, the channel estimation method includes: Receiving a reference signal, the reference signal including multiple layers transmitted through multiple ports respectively connected to multiple antennas; Determine whether inter-layer interference occurs relative to the reference signal; When it is determined that the inter-layer interference does not occur, estimate the channel by executing the first algorithm; and When it is determined that the inter-layer interference occurs, the channel is estimated by executing a second algorithm different from the first algorithm. The channel estimation method as described in claim 8, The reference signal is received via a first frequency channel and a second frequency channel with different carriers, and Determining whether the inter-layer interference occurs includes: Obtaining a correlation value by performing correlation on a first channel matrix corresponding to the first frequency channel and a second channel matrix corresponding to the second frequency channel; and Determine whether the inter-layer interference occurs based on the correlation value and the predetermined first reference value. The channel estimation method as described in claim 9, Wherein determining whether the inter-layer interference occurs based on the correlation value and the first reference value includes: Comparing the correlation value with the first reference value; and When the correlation value is less than the first reference value, it is determined that the inter-layer interference occurs. The channel estimation method as described in claim 8, Wherein determining whether the inter-layer interference occurs includes: Obtaining the maximum delay spread of the reference signal; and Determine whether the inter-layer interference occurs based on the maximum delay spread and a predetermined second reference value. The channel estimation method described in claim 11, Wherein determining whether the inter-layer interference occurs based on the maximum delay spread and the second reference value includes: Comparing the maximum delay spread with the second reference value; and When the maximum delay spread is greater than the second reference value, it is determined that the inter-layer interference occurs. The channel estimation method as described in claim 8, The reference signal is received via a first frequency channel and a second frequency channel with different carriers, and Determining whether the inter-layer interference occurs includes: Generating an interference metric based on the difference between the first channel reception signal received via the first frequency channel and the second channel reception signal received via the second frequency channel; and Determine whether the inter-layer interference occurs based on the normalized value of the interference metric and the third reference value. The channel estimation method as described in claim 13, Wherein determining whether the inter-layer interference occurs based on the normalized value of the interference metric and the third reference value includes: Comparing the normalized value with the third reference value; and When the normalized value is greater than the third reference value, it is determined that the inter-layer interference occurs. The channel estimation method as described in claim 13, The third reference value is determined based on the variance of the noise that occurs when the reference signal is received. The channel estimation method as described in claim 8, further including Estimate the channel based on the similarity between the data sequence of the signal received at the first port and the data sequence of the signal received at the second port, The wireless communication device includes a first port connected to a first antenna and a second port connected to a second antenna, and the reference signal includes the first port reception signal received through the first port And the second port receiving signal received via the second port. The channel estimation method as described in claim 16, Wherein when it is determined that the inter-layer interference occurs, the channel estimation is performed based on the similarity between the data sequence of the signal received at the first port and the data sequence of the signal received at the second port, And The estimation of the channel based on the similarity between the data sequence of the first port received signal and the data sequence of the second port received signal includes: Based on the interference correlation value indicating the similarity between the data sequence of the signal received by the first port and the data sequence of the signal received by the second port, the determination of the signal received by the first port Whether the data sequence is the same as the data sequence of the signal received by the second port; When it is determined that the data sequence of the signal received by the first port is the same as the data sequence of the signal received by the second port, the channel is estimated based on the second algorithm; and When it is determined that the data sequence of the signal received by the first port is not the same as the data sequence of the signal received by the second port, the channel is estimated based on a third algorithm different from the second algorithm . The channel estimation method as described in claim 17, Wherein determining whether the data sequence of the signal received by the first port is the same as the data sequence of the signal received by the second port includes: Generating the interference correlation value based on the difference between the received signal at the first port and the received signal at the second port; Comparing the interference correlation value with a predetermined fourth reference value; and When the interference correlation value is greater than the fourth reference value, it is determined that the data sequence of the signal received by the first port is the same as the data sequence of the signal received by the second port. The channel estimation method as described in claim 17, Wherein, assuming that the inter-layer interference does not occur, the first algorithm estimates the channel; Taking the inter-layer interference into consideration, the second algorithm estimates the channel; and The third algorithm estimates the channel based on the sum of the variance of the noise in the reference signal and the variance of the noise in the received signal at the first port and the received signal at the second port. The channel estimation method described in claim 8 further includes: Output reference signal setting information from the base station to the terminal; Determine whether the current channel matrix is suitable for signal transmission and reception based on the reference signal setting information; and When the current channel matrix is not suitable for the signal transmission and reception, a channel setting change request is output from the terminal to the base station. The channel estimation method described in claim 20, The channel setting change request includes information about the channel type suitable for the signal transmission and reception. The channel estimation method described in claim 20 further includes The base station changes the channel type in response to the channel setting change request, and outputs the reference signal to the terminal. A wireless communication system includes: The base station is configured to output reference signal setting information; and The terminal is configured to determine whether the current channel matrix is suitable for signal transmission and reception based on the reference signal setting information, and when the current channel matrix is not suitable for the signal transmission and reception, output the channel setting change to the base station request. The wireless communication system described in claim 23, The channel setting change request includes information about the channel type suitable for the signal transmission and reception. The wireless communication system described in claim 23, The base station changes the channel type in response to the channel setting change request, and outputs the reference signal to the terminal according to the changed channel type.

Images