KR102355979B1 - Communication device and control method thereof - Google Patents

Abstract

A communication device and a method for controlling the same are disclosed. A communication device according to various embodiments of the present disclosure includes a transceiver configured to receive a wireless signal and a processor electrically connected to the transceiver, wherein the processor receives a data signal including data received through the wireless signal Storing in a first buffer according to a first delay period, storing a channel signal including channel estimation information on a transmission channel of the radio signal in a second buffer according to a second delay period, and storing information related to the radio signal Based on the coefficients of the low-pass filter and the group delay associated with the low-pass filter, the equalization is performed by outputting at least a portion of the channel signal stored in the second buffer based on the determined group delay and the first delay period. can be done

Description

Communication device and control method thereof

The present disclosure relates to a communication device and a method for controlling the same, and to a communication device for equalizing a received signal and a method for controlling the same.

As high-speed mobile communication systems such as Wideband Code Division Multiple Access (WCDMA) or High Speed Downlink Packet Access (HSDPA) are commercialized, an equalizer-based receiver suitable for the high-speed mobile communication system is being researched and developed.

The equalizer-based receiver may include a channel estimator and an equalizer for equalizing a channel based on a channel estimated through the channel estimator. An equalizer according to the prior art is disclosed in, for example, US Patent No. 7,675,962.

On the other hand, the above information is only presented as background information to help the understanding of the present disclosure. No determination has been made, and no claim is made as to whether any of the above is applicable as prior art to the present disclosure.

According to the receiver according to the prior art, in performing equalization on a received signal, the same low-pass filter coefficient (or bandwidth) is used for all taps, or an algorithm for changing the coefficient for each tap is applied. In this case, it is difficult to expect high reliability of the equalization by determining the coefficient in consideration of only the Doppler frequency (or Doppler spread).

In addition, in the receiver according to the prior art (for example, the receiver disclosed in US Patent No. 7,675,962), when an algorithm for changing the coefficient of the low-pass filter for each tap is applied, the The amount of computation for changing the bandwidth increases, and as a result, power consumption of the receiver increases.

According to various embodiments of the present disclosure, the signal-to-noise ratio (SNR) of the received signal using the received signal strength (eg, RSSI) already calculated in a component such as an automatic gain controller ) and determining the coefficient of the low-pass filter based on the estimated Doppler frequency and the calculated signal-to-noise ratio (SNR) to perform equalization, higher reliability and lower power consumption than a receiver according to the prior art A communication device capable of reducing is provided.

According to various embodiments of the present disclosure, the reception is performed by controlling the channel signal and the data signal to have a constant group delay based on the determined filter coefficient, and performing equalization using the channel signal and the data signal having a constant group delay. An improved communication device is provided.

According to various embodiments of the present disclosure, a signal-to-noise ratio of a received signal is calculated using the received signal strength already calculated in a component such as an automatic gain controller, and based on the estimated Doppler frequency and the calculated signal-to-noise ratio There is provided a control method of a communication device capable of reducing power consumption and having higher reliability than a receiver according to the related art in performing equalization by determining the coefficients of the low-pass filter by using .

According to various embodiments of the present disclosure, the reception is performed by controlling the channel signal and the data signal to have a constant group delay based on the determined filter coefficient, and performing equalization using the channel signal and the data signal having a constant group delay. A method of controlling a communication device with improved performance is provided.

A communication device according to various embodiments of the present disclosure includes a transceiver configured to receive a wireless signal and a processor electrically connected to the transceiver, wherein the processor receives a data signal including data received through the wireless signal Storing in a first buffer according to a first delay period, storing a channel signal including channel estimation information on a transmission channel of the radio signal in a second buffer according to a second delay period, and storing information related to the radio signal Based on the coefficients of the low-pass filter and the group delay associated with the low-pass filter, the equalization is performed by outputting at least a portion of the channel signal stored in the second buffer based on the determined group delay and the first delay period. can be done

A method of controlling a communication device according to various embodiments of the present disclosure includes receiving a wireless signal, and storing a data signal including data received through the wireless signal in a first buffer according to a first delay period a process of storing a channel signal including channel estimation information on a transmission channel of the radio signal in a second buffer according to a second delay period; and coefficients of a low-pass filter based on the information related to the radio signal and determining a group delay related to the low-pass filter, and performing equalization by outputting at least a portion of the channel signal stored in the second buffer based on the determined group delay and the first delay period. can

According to various embodiments of the present disclosure as described above, the signal-to-noise ratio of the received signal is calculated using the received signal strength already calculated in a component such as an automatic gain controller, and the estimated Doppler frequency and the calculated signal-to-noise ratio are used. By determining the coefficients of the low-pass filter based on the noise ratio, reliability can be increased and power consumption can be reduced compared to a receiver according to the related art in performing equalization.

According to various embodiments of the present disclosure as described above, the channel signal and the data signal are controlled to have a constant group delay based on the determined filter coefficient, and equalization is performed using the channel signal and the data signal having a constant group delay. By doing so, the reception performance can be improved.

The effects of the present invention are not limited to the effects described above, and it is apparent to those skilled in the art that various effects are inherent in the present specification.

1A is an exemplary diagram for describing a communication device according to various embodiments of the present disclosure.
1B is an exemplary diagram for explaining a user terminal equipped with a communication device according to various embodiments of the present disclosure.
FIG. 2A is an exemplary diagram for explaining components of the processor illustrated in FIG. 1A .
2B is an exemplary diagram for describing components of a channel estimation module according to various embodiments of the present disclosure.
FIG. 2C is an exemplary diagram for describing a function/functions or operation/actions for compensating for group delay according to various embodiments of the present disclosure;
FIG. 3 exemplarily illustrates the correlation between the mean square error and filter coefficients according to the signal-to-noise ratio when the maximum group delay is limited to 5 symbols in the first-order low-pass filter and the maximum Doppler frequency is 5.9 Hz. It is a drawing.
4 is an exemplary diagram for explaining a method of controlling a communication device according to various embodiments of the present disclosure.
5 is an exemplary diagram for describing a communication device according to various embodiments of the present disclosure.
6 is an exemplary diagram for describing a channel estimator according to various embodiments of the present disclosure.
7 is an exemplary diagram for explaining any one channel estimator included in a cluster of channel estimators according to various embodiments of the present disclosure.
8 is an exemplary diagram for describing a channel estimator controller according to various embodiments of the present disclosure.
9 is an exemplary diagram for describing an LPF control and channel weight generation module according to various embodiments of the present disclosure.

Hereinafter, various embodiments of the present disclosure are described with reference to the accompanying drawings. However, this is not intended to limit the technology described in the present disclosure to specific embodiments, and it should be understood that the present disclosure includes various modifications, equivalents, and/or alternatives of the embodiments of the present disclosure. . In connection with the description of the drawings, like reference numerals may be used for like components.

In the present disclosure, expressions such as “have,” “may have,” “include,” or “may include” indicate the presence of a corresponding characteristic (eg, a numerical value, function, operation, or component such as a part). and does not exclude the presence of additional features.

In this disclosure, expressions such as "A or B," "at least one of A and/and B," or "one or more of A or/and B" may include all possible combinations of the items listed together. . For example, "A or B," "at least one of A and B," or "at least one of A or B" means (1) includes at least one A, (2) includes at least one B; Or (3) it may refer to all cases including both at least one A and at least one B.

As used in the present disclosure, expressions such as “first,” “second,” “first,” or “second,” may modify various elements, regardless of order and/or importance, and refer to one element. It is used only to distinguish it from other components, and does not limit the components. For example, the first user equipment and the second user equipment may represent different user equipment regardless of order or importance. For example, without departing from the scope of the rights described in the present disclosure, a first component may be referred to as a second component, and similarly, the second component may also be renamed as a first component.

One component (eg, a first component) is "coupled with/to (operatively or communicatively)" to another component (eg, a second component); When referring to "connected to", it should be understood that the certain element may be directly connected to the other element or may be connected through another element (eg, a third element). On the other hand, when it is said that a component (eg, a first component) is "directly connected" or "directly connected" to another component (eg, a second component), the component and the It may be understood that other components (eg, a third component) do not exist between other components.

The expression “configured to (or configured to)” as used in this disclosure, depending on the context, for example, “suitable for,” “having the capacity to” ," "designed to," "adapted to," "made to," or "capable of." The term “configured (or configured to)” may not necessarily mean only “specifically designed to” in hardware. Instead, in some circumstances, the expression “a device configured to” may mean that the device is “capable of” with other devices or parts. For example, the phrase “a control module configured (or configured to perform) A, B, and C” refers to a dedicated control module (eg, an embedded control module), or one or more software stored on a storage module device, for performing the corresponding operations. By executing the programs, it may mean a generic-purpose processor (eg, a CPU or an application processor) capable of performing corresponding operations.

Terms used in the present disclosure are used only to describe specific embodiments, and may not be intended to limit the scope of other embodiments. The singular expression may include the plural expression unless the context clearly dictates otherwise. Terms used herein, including technical or scientific terms, may have the same meanings as commonly understood by one of ordinary skill in the art described in the present disclosure. Among the terms used in the present disclosure, terms defined in a general dictionary may be interpreted with the same or similar meaning as the meaning in the context of the related art, and unless explicitly defined in the present disclosure, ideal or excessively formal meanings is not interpreted as In some cases, even terms defined in the present disclosure cannot be construed to exclude embodiments of the present disclosure.

Hereinafter, a communication device and a user terminal according to various embodiments are described with reference to the accompanying drawings. In the present disclosure, the term user may refer to a person using a communication device, an apparatus (eg, artificial intelligence device) using the communication device, or a person using the user terminal or an apparatus using the user terminal. can

Referring to FIG. 1A , a communication device 100 according to various embodiments of the present disclosure may include at least one of a transceiver 101 , a processor 102 , and a memory 103 .

The transceiver 101 is, for example, between the communication device 100 and an external device (eg, the first external electronic device 130 , the second external electronic device 140 , or the server 150 ). Communication can be established. For example, the transceiver 101 may be connected to the network 120 through wireless communication or wired communication to communicate with the external device. According to some embodiments, the “transceiver 101” may be referred to as being replaced by various terms such as “communication module” or “communication interface”.

The wireless communication is, for example, as a cellular communication protocol, for example, long-term evolution (LTE), LTE Advance (LTE-A), code division multiple access (CDMA), wideband CDMA (WCDMA), UMTS ( At least one of universal mobile telecommunications system), Wireless Broadband (WiBro), and Global System for Mobile Communications (GSM) may be used. Also, wireless communication may include, for example, short-range communication. The short-range communication may include, for example, at least one of wireless fidelity (WiFi), Bluetooth, near field communication (NFC), or global navigation satellite system (GNSS). GNSS is, depending on the area or bandwidth used, for example, GPS (Global Positioning System), Glonass (Global Navigation Satellite System), Beidou Navigation Satellite System (hereinafter "Beidou") or Galileo, the European global satellite-based navigation system. It may include at least one.

The wired communication may include, for example, at least one of universal serial bus (USB), high definition multimedia interface (HDMI), recommended standard232 (RS-232), and plain old telephone service (POTS). The network 120 may include at least one of a telecommunications network, for example, a computer network (eg, LAN or WAN), the Internet, or a telephone network.

The processor 102 may include a communication processor (CP). According to various embodiments of the present disclosure, the processor 102 may further include one or more of a central processing unit (CPU) and an application processor (AP). The processor 102 may, for example, execute an operation or data processing related to control and/or communication of at least one other component of the communication device 100 . According to various embodiments of the present disclosure, the term “processor” is, in some embodiments, replaced with various terms such as “control module”, “unit” or “controller” can be used

The memory 103 may include volatile and/or non-volatile memory. The memory 103 may store, for example, commands or data related to at least one other component of the communication device 100 . According to an embodiment, the memory 103 may store software and/or a program. The program may include, for example, a kernel, middleware, an application programming interface (API) and/or an application program (or "application"). In FIG. 1A , a case in which the memory 103 is included in the communication device 100 is illustrated, but this is an example for describing the present disclosure. According to various embodiments of the present disclosure, the memory 103 may be manufactured while being omitted from the manufacturing process of the communication device 100 .

1B is an exemplary diagram for explaining a user terminal equipped with a communication device according to various embodiments of the present disclosure.

Referring to FIG. 1B , the user terminal 110 according to various embodiments of the present disclosure may include the communication device 100 , a display 112 , and an input/output interface 114 .

The display 112 may include, for example, a liquid crystal display (LCD), a light-emitting diode (LED) display, an organic light-emitting diode (OLED) display, or microelectromechanical systems (MEMS) displays, or electronic paper displays. The display 112 may display, for example, various contents (eg, text, image, video, icon, or symbol) to the user. The display 112 may include a touch screen, and may receive, for example, a touch input using an electronic pen or a part of the user's body, a gesture, a proximity, or a hovering input.

The input/output interface 114 may serve as an interface capable of transmitting, for example, a command or data input from a user or other external device to other component(s) of the user terminal 110 . In addition, the input/output interface 114 may output a command or data received from other component(s) of the user terminal 110 to a user or other external device.

According to various embodiments of the present disclosure, the user terminal 110 may further include a storage module (eg, a memory) or a processor (eg, an application processor).

FIG. 2A is an exemplary diagram for explaining functions/functions or operations/operations of the processor illustrated in FIG. 1A . 2B is an exemplary diagram for describing a channel estimation module according to various embodiments of the present disclosure.

Referring to FIG. 2 , the processor 102 may include a downsampling module 210 , a channel estimation module 220 , an equalizing module 230 , a control module 240 , and a data buffer 250 .

The down-sampling module 210 down-samples a signal in which the radio signal received by the transceiver 101 is sampled at several times the chip rate (eg, 4 times the chip rate) to 2 times the chip rate, so that the channel may be transmitted to the estimation module 220 . According to various embodiments of the present disclosure, the chip speed may be 3.84 Mcps, but this is only an example for describing the present invention. According to various embodiments of the present disclosure, the radio signal received by the transceiver 101 is, for example, passed through a matched filter (eg, matched filter 511) and then the number It can be converted to a digital signal sampled at twice the chip rate.

)을 포함하는 채널 신호를 특정한 저장 주기에 따라 일시적으로 저장하는(다른 말로, 특정한 지연 주기에 따라 지연시켜 출력하는) 군 지연 보상 버퍼(224)를 포함할 수 있다. 상기 채널 추정은, 상기 무선 신호 또는 상기 데이터가 전송되는 전송 채널에 관한 추정일 수 있다. 상기 군 지연 보상 버퍼(224)의 특정한 저장 주기(예를 들면, 1 심볼 주기(본 개시에서 간략하게, "심볼"이라고 언급될 수 있다))는, 예를 들어, 데이터 버퍼(250)의 저장 주기보다 작은 값으로 미리 지정될 수 있다. 상기 저역 통과 필터(202a)는 예를 들어, 적어도 하나의 IIR(Infinite Impulse Response) 필터를 포함할 수 있다. 본 개시의 다양한 실시예들에 따르면, 상기 데이터 버퍼(250)는 상기 무선 신호를 통하여 수신된 특정한 데이터를 포함하는 데이터 신호를 미리 지정된 저장 주기(예를 들면, 5 심볼)에 따라 일시적으로 저장할 수 있다. 본 개시의 다양한 실시예들에 따르면, 상기 군 지연 보상 버퍼(224) 및 상기 데이터 버퍼(250)는, 상기 각각의 버퍼에 입력되는 신호를 교대로 또한 순차적으로 저장하고 출력하는 선입선출 (First Input First Output) 구조의 버퍼일 수 있다. 일부 실시예들에서, 상기 "저장 주기"라는 용어는, 데이터 출력의 관점에서 "지연 주기", "지연 시간" 또는 "출력 주기"라는 용어로도 언급될 수 있다. The channel estimation module 220 includes a low-pass filter 222 that performs low-pass filtering on the received signal and a channel estimation value (eg,

) may include a group delay compensation buffer 224 for temporarily storing (in other words, delaying and outputting a channel signal according to a specific storage period) according to a specific storage period. The channel estimation may be an estimation regarding a transmission channel through which the radio signal or the data is transmitted. A specific storage period of the group delay compensation buffer 224 (eg, one symbol period (which may be briefly referred to as a “symbol” in this disclosure)) is, for example, a storage period of the data buffer 250 . It may be pre-specified as a value smaller than the period. The low-pass filter 202a may include, for example, at least one Infinite Impulse Response (IIR) filter. According to various embodiments of the present disclosure, the data buffer 250 may temporarily store a data signal including specific data received through the wireless signal according to a predetermined storage period (eg, 5 symbols). have. According to various embodiments of the present disclosure, the group delay compensation buffer 224 and the data buffer 250 alternately and sequentially store and output the signals input to the respective buffers. First Output) structure of the buffer. In some embodiments, the term “storage period” may also be referred to as a “delay period”, “delay time” or “output period” in terms of data output.

The channel estimation module 220 is, for example, based on the received signal strength (eg, Received Signal Strength Indication (RSSI)) estimated by an automatic gain controller (AGC) electrically connected to the communication device 100 . related information may be received from the automatic gain controller. The channel estimation module 220 may estimate (in other words, calculate) a signal-to-noise ratio (SNR) of the radio signal received by the transceiver 101 using the received signal strength. The channel estimation module 220 according to various embodiments of the present disclosure may estimate a signal-to-noise ratio (SNR) for the received radio signal using the received signal strength estimated by the automatic gain controller. The receiver according to the prior art needs to calculate the power of the received radio signal at, for example, twice the chip rate and accumulate the calculated power in order to obtain the received signal strength. However, the communication device 100 according to various embodiments of the present disclosure uses the received signal strength estimated by the automatic gain controller to estimate the signal-to-noise ratio, so that an additional operation for estimating the received signal strength is performed. As it may be omitted, the amount of computation may be reduced compared to the receiver according to the prior art in performing the equalization.

는 아래의 수학식 1과 같이 표현될 수 있다.In the case of receiving channel information through L taps in a wireless communication system, the received signal

can be expressed as in Equation 1 below.

는 송신 신호의 (k-m)번째 샘플, h[m]은 m번째 탭의 이론적인 채널 값, n[k]는 잡음 신호의 k번째 샘플을 의미할 수 있다. 수학식 1에서는, 가간섭성 시간(coherence time) 동안에 상기 h[m] 값이 시간(예를 들면, 상기 샘플 k)에 따라 변하지 않는 경우를 가정하였다. 송신 신호

는 아래의 수학식 2와 같이 표현될 수 있다.In Equation 1 above,

may mean the (km)th sample of the transmission signal, h[m] may mean the theoretical channel value of the mth tap, and n[k] may mean the kth sample of the noise signal. In Equation 1, it is assumed that the value of h[m] does not change with time (eg, the sample k) during a coherence time. transmit signal

can be expressed as in Equation 2 below.

는 복소 확산 신호의 k번째 샘플 이며, p

는 파일럿 신호의 k번째 샘플,

는 q번째 사용자의 신호, Q는 사용자의 수,

는 파일럿 채널 신호의 에너지,

는 q번째 사용자 신호의 에너지를 의미할 수 있다. 상기 수신 신호

는 벡터의 형태로

와 같이 표현될 수 있고, 여기서,

는 파일럿 신호의 누적 구간(period), 다른 말로, 채널 추정 값에 대한 업데이트 주기를 의미할 수 있다. 상기

는 예를 들어, 1 심볼 일 수 있으며, 상기

가 512 칩(chip)인 경우, 상기 1 심볼은 133.3 마이크로초(μs)일 수 있다. T는 전치 행렬(transposed matrix),

는 수신 신호의 (k-

+1) 번째 샘플의 벡터 표현일 수 있다. 상기

동안의 확산 신호는 대각 행렬(diagonal matrix)

로 표현될 수 있고, 파일럿 신호는

로 표현될 수 있다. 따라서, 역 확산된 파일럿 신호는

로 표현될 수 있으며 r 번째 탭에 대한, 저역 통과 필터링 이전의 채널 추정 값

은 아래의 수학식 3과 같이 표현될 수 있다.In Equation 2 above,

is the kth sample of the complex spread signal, p

is the kth sample of the pilot signal,

is the signal of the qth user, Q is the number of users,

is the energy of the pilot channel signal,

may mean the energy of the q-th user signal. the received signal

is in the form of a vector

It can be expressed as, where

may mean an accumulation period of a pilot signal, in other words, an update period for a channel estimation value. remind

may be, for example, 1 symbol,

In the case of 512 chips, one symbol may be 133.3 microseconds (μs). T is the transposed matrix,

is the (k-) of the received signal

+1) may be a vector representation of the th sample. remind

The spread signal during

It can be expressed as , the pilot signal is

can be expressed as Therefore, the despread pilot signal is

It can be expressed as , and the channel estimate before low-pass filtering for the r-th tap.

can be expressed as in Equation 3 below.

는 역 확산된 파일럿 신호에 대한 공액 전치 행렬(conjugate transpose matrix)이고,

은 수신 신호의 (k+r)번째 샘플에 대한 벡터 표현이고, h[r]은 r 번째 탭의 이론상의 채널 값, 다시 말하면, 상기 채널 추정 모듈(220)이 추정하고자 하는 목표(target) 채널 값이고,

은 송신 신호의 (k+r-m) 번째 샘플에 대한 벡터 표현이고,

은 m 번째 탭의 이론적인 채널 값이고,

은 잡음 신호의 (k+r) 번째 샘플에 대한 백터 표현을 의미할 수 있다. 간략하게, 상기 수학식 3에서,

는 채널 신호 부분(part)으로,

는 잡음 신호 부분으로 구분될 수 있다.In Equation 3 above

is a conjugate transpose matrix for the despread pilot signal,

is a vector representation of the (k+r)-th sample of the received signal, and h[r] is the theoretical channel value of the r-th tap, that is, the target channel that the channel estimation module 220 intends to estimate. is the value,

is the vector representation of the (k+rm)-th sample of the transmitted signal,

is the theoretical channel value of the mth tap,

may mean a vector representation of the (k+r)-th sample of the noise signal. Briefly, in Equation 3 above,

is the channel signal part,

can be divided into a noise signal part.

이 상기 저역 통과 필터(220)에 의한 저역 통과 필터링이 수행된 이후의 신호를

라고 하면, 잡음과 간섭이 감소된 채널 추정 값

은 아래의 수학식 4와 같이 표현될 수 있다.the channel estimate

The signal after the low-pass filtering by the low-pass filter 220 is performed

, the channel estimate with reduced noise and interference

can be expressed as in Equation 4 below.

는 상기 저역 통과 필터(302)에 의한 저역 통과 필터링 후 감소(reduction)된 잡음의 분산을 의미할 수 있다. 상기

가 매우 작을 경우,

는 아래의 수학식 5와 같이 표현될 수 있다. 상기

는,

에 대한 전력(power)의 평균을 의미할 수 있다. 아래의 수학식 5는 상기 수학식 3에서 언급된 채널 신호 부분의 세기와 관련될 수 있다.In Equation 4 above,

may mean a dispersion of reduced noise after low-pass filtering by the low-pass filter 302 . remind

If is very small,

can be expressed as in Equation 5 below. remind

Is,

may mean an average of power for . Equation 5 below may be related to the intensity of the channel signal portion mentioned in Equation 3 above.

를 송신 신호 세기라고 할 때,

는 아래의 수학식 6과 같이 표현될 수 있다.Also, the intensity of the noise part expressed in Equation 3 may be calculated using the received signal intensity.

When is the transmit signal strength,

can be expressed as in Equation 6 below.

는, 저역 통과 필터링이 수행되기 이전의 채널 추정 값에 대한 잡음의 분산을 의미할 수 있다. 상기 채널 추정 모듈(202)은, 복수의 탭들을 포함할 수 있고, 상기 무선 신호가 복수의 탭들을 통하여 수신되는 경우, 아래의 수학식 7을 이용하여 각각의 탭에 대한 신호 대 잡음비를 추정할 수 있다. In Equation 6 above,

may mean the dispersion of noise with respect to the channel estimation value before low-pass filtering is performed. The channel estimation module 202 may include a plurality of taps, and when the wireless signal is received through a plurality of taps, it is possible to estimate a signal-to-noise ratio for each tap using Equation 7 below. can

The channel estimation module 220 may estimate a Doppler frequency of the received radio signal. The channel estimation module 220 may determine a coefficient of the low-pass filter and a group delay corresponding to the coefficient, based on the estimated signal-to-noise ratio and Doppler frequency. The relationship between the estimated signal-to-noise ratio and Doppler frequency and the coefficients of the low-pass filter and the group delays corresponding to the coefficients (in other words, the group delays caused by the low-pass filtering) are looked up in the memory 103 . It may be stored in advance in the form of an up table. In the lookup table, for example, when the estimated Doppler frequency is 5.9 Hz and the estimated signal-to-noise ratio is 18 (dB), the coefficient of the low-pass filter is 0.125 and a group corresponding to the coefficient of the low-pass filter The delay may include a correspondence of 5 symbols. According to various embodiments of the present disclosure, the coefficients of the low-pass filter included in the lookup table are mean square errors of the signal before the low-pass filtering is performed and the signal after the low-pass filtering is performed. may be a coefficient with a minimum. The mean square error may be expressed as, for example, Equation 8 below.

는 입력 샘플간 간격,

는 채널의 에너지에 대한 분산을 의미할 수 있다.

는 잡음에 대한 분산,

는 도플러 주파수를 의미할 수 있다. E[]는 평균, g[]는 상기 저역 통과 필터(222)의 임펄스 응답을 의미할 수 있으며, 예를 들어, g[l]은 상기 임펄스 응답의 l번째 값을 의미할 수 있다. h[n-l]은, (n-l)번째 탭의 이론적인 채널 값, h[n-Δ]는 n번째 탭에서 군 지연이 제거(cancellation)된 이론적인 채널 값을 의미할 수 있다. v[]는 잡음을 의미할 수 있으며, 예를 들어, v[n-l]은 잡음 신호의 (n-l)번째 샘플을 의미할 수 있다.

는 0차 제1종 베셀 함수(zeroth order Bessel function of the first kind)를 의미할 수 있다.In Equation 8, Δ is the group delay generated by the low-pass filter 222,

is the interval between input samples,

may mean the distribution of energy of the channel.

is the variance for noise,

may mean a Doppler frequency. E[] may mean the average, g[] may mean the impulse response of the low-pass filter 222, for example, g[l] may mean the l-th value of the impulse response. h[nl] may mean a theoretical channel value of the (nl)-th tap, and h[n-Δ] may mean a theoretical channel value from which group delay is canceled in the n-th tap. v[] may mean noise, for example, v[nl] may mean the (nl)th sample of the noise signal.

may mean a zeroth order Bessel function of the first kind.

을 특정한 시간만큼 지연시켜 출력하도록 상기 군 지연 보상 버퍼(224)를 제어할 수 있다. 상기 제어 모듈(240)은, 상기 룩 업 테이블을 참조하여 결정된 상기 저역 통과 필터(222)의 군 지연과, 상기 데이터 버퍼(250)의 저장 주기를 기초로 상기 상기 군 지연 보상 버퍼(224)에서 출력되는 채널 추정 값에 대한 지연 시간을 결정하고, 상기 지연 시간에 따라 상기 채널 추정 값

를 출력하여 군 지연을 적응적으로(adaptively) 보상할 수 있다. 상기 군 지연을 적응적으로 보상하는 기능 또는 동작이 도 2c를 참조하여 설명된다. 도 2c는 본 개시의 다양한 실시예들에 따른 군 지연을 보상하는 기능/기능들 또는 동작/동작들을 설명하기 위한 예시 도면이다.The control module 240 is input to the group delay compensation buffer 224, the low-pass filtering is performed, the channel estimation value

The group delay compensation buffer 224 may be controlled to delay output by a specific time. The control module 240 performs the group delay in the group delay compensation buffer 224 based on the group delay of the low-pass filter 222 determined by referring to the lookup table and the storage period of the data buffer 250 . Determine a delay time for an output channel estimate value, and determine the channel estimate value according to the delay time

can be output to compensate for the group delay adaptively. A function or operation of adaptively compensating for the group delay is described with reference to FIG. 2C . FIG. 2C is an exemplary diagram for describing a function/functions or operation/actions for compensating for group delay according to various embodiments of the present disclosure;

을 포함하는 채널 신호(260)는 상기 저역 통과 필터(222)에 입력 및 저장될 수 있다. 또한, 특정한 데이터를 포함하는 데이터 신호(270)는 상기 데이터 버퍼(250)에 입력 및 저장될 수 있다. 도 2c에서는, 본 개시의 설명을 위하여 상기 데이터 신호(270)의 저장 주기가 5 심볼인 경우가 예시적으로 도시된다. 상기 저역 통과 필터(222)에 의한 저역 통과 필터링이 수행된 채널 추정 값

를 포함하는 채널 신호(261)는, 상기 저역 통과 필터링에 의하여 군 지연이 발생될 수 있다. 도 2c에서는, 상기 군 지연이 2 심볼인 경우가 예시적으로 도시된다. 지연된 채널 신호(261a)는 상기 군 지연 보상 버퍼(224)에 입력될 수 있다. 상기 제어 모듈(240)은, 상기 저역 통과 필터링에 따른 군 지연을 보상하기 위하여, 상기 군 지연 보상 버퍼(224)에 입력된 채널 신호(261a)를 지연시킬 수 있다. 상기 제어 모듈(240)은, 상기 데이터 버퍼(250)의 저장 주기(예를 들면, 5 심볼) 및 상기 룩 업 테이블에 기초하여 결정된 군 지연(예를 들면, 2 심볼)을 기초로, 상기 군 지연 보상 버퍼(224)에 입력된 채널 신호(261a)를 상기 데이터 버퍼(250)의 저장 주기와 일치되도록 지연시켜 출력할 수 있다. 예를 들어, 상기 제어 모듈(240)은, 상기 채널 신호(261a)를 3 심볼 지연시켜 출력할 수 있고, 상기 지연된 신호(261b)는 상기 이퀄라이징 모듈(230)에 입력될 수 있다. 또한, 상기 제어 모듈(240)은, 새롭게 입력된 데이터 신호(280)가 아닌, 상기 데이터 버퍼(250)로부터 5 심볼 지연된 데이터 신호(270)를 상기 이퀄라이징 모듈(230)로 전송할 수 있다. 이와 같이, 본 개시의 다양한 실시예들에 따른 통신 디바이스(100)는, 상기 채널 신호(예를 들면, 채널 신호 261a)의 지연 주기를 상기 저역 통과 필터(222)의 군 지연에 따라 적응적으로 변경하여, 다양한 무선 통신 환경에서 일정한 채널 추정 이득 또는 이퀄라이징 이득을 가질 수 있다.Referring to FIG. 2C , the channel estimation value

The channel signal 260 including ? may be input to and stored in the low-pass filter 222 . Also, the data signal 270 including specific data may be input and stored in the data buffer 250 . In FIG. 2C , a case in which the storage period of the data signal 270 is 5 symbols is exemplarily illustrated for the purpose of explanation of the present disclosure. Channel estimation value on which low-pass filtering by the low-pass filter 222 is performed

In the channel signal 261 including , a group delay may be generated by the low-pass filtering. In FIG. 2C , a case in which the group delay is 2 symbols is exemplarily shown. The delayed channel signal 261a may be input to the group delay compensation buffer 224 . The control module 240 may delay the channel signal 261a input to the group delay compensation buffer 224 in order to compensate for the group delay caused by the low-pass filtering. The control module 240 is configured to, based on a storage period (eg, 5 symbols) of the data buffer 250 and a group delay (eg, 2 symbols) determined based on the look-up table, The channel signal 261a input to the delay compensation buffer 224 may be delayed to match the storage period of the data buffer 250 and output. For example, the control module 240 may output the channel signal 261a with a delay of 3 symbols, and the delayed signal 261b may be input to the equalizing module 230 . Also, the control module 240 may transmit the data signal 270 delayed by 5 symbols from the data buffer 250 to the equalizing module 230 , rather than the newly input data signal 280 . As such, the communication device 100 according to various embodiments of the present disclosure adaptively adjusts the delay period of the channel signal (eg, the channel signal 261a) according to the group delay of the low-pass filter 222 . By changing it, it can have a constant channel estimation gain or equalizing gain in various wireless communication environments.

과 상기 이론적인 채널 값 h[r] 사이에서의 평균 제곱 오차가 최소화될 수 있다. 상기 가중치는 아래의 수학식 9를 통하여 연산될 수 있다.The control module 230 according to various embodiments of the present disclosure may multiply the channel signal 261b output from the group delay compensation buffer 224 by a weight, and then transmit it to the equalizing module 230 . Through the weight, the channel estimate value

and the mean square error between the theoretical channel value h[r] can be minimized. The weight may be calculated through Equation 9 below.

은 r 번째 탭에 대한 신호(예를 들면, 채널 신호)가 통과하는 저역 통과 필터의 임펄스 응답의 n번째 값이고, β는 특정한 탭에 대한 잡음의 정도에 따라 상기 가중치의 적용 여부를 결정하기 위하여 사용되는 프로그램 가능한 값을 의미할 수 있다. 예를 들어, 상기 특정한 탭(예를 들면, r번째 탭)에 대한 잡음의 세기가 임계치 이상인 경우 상기 가중치가 0으로 설정될 수 있으며, 즉, 상기 β는 채널 추정 값에 대한 활성 여부를 결정하기 위한 프로그램 가능한 값을 의미할 수 있다. 본 개시의 다양한 실시예들에 따르면, 상기 제어 모듈(240)은 상기 채널 추정 값

이 상기 군 지연 보상 버퍼(224)에 입력되기 이전에 상기 채널 추정 값

에 상기 가중치를 곱하는 연산을 수행할 수도 있다. In Equation 9 above,

is the n-th value of the impulse response of the low-pass filter through which the signal for the r-th tap (eg, a channel signal) passes, and β is the level of noise for a specific tap. It may mean a programmable value used. For example, when the noise intensity for the specific tap (eg, the r-th tap) is greater than or equal to a threshold, the weight may be set to 0, that is, the β is used to determine whether a channel estimation value is active. It may mean a programmable value for According to various embodiments of the present disclosure, the control module 240 is the channel estimation value.

The channel estimate value before being input to the group delay compensation buffer 224

It is also possible to perform an operation of multiplying by the weight.

The equalizing module 203 may perform equalization using the channel signal 261b multiplied by the weight and the data signal 270 .

FIG. 3 exemplarily illustrates the correlation between the mean square error and filter coefficients according to the signal-to-noise ratio when the maximum group delay is limited to 5 symbols in the first-order low-pass filter and the maximum Doppler frequency is 5.9 Hz. It is a drawing.

Referring to FIG. 3 , the dotted line is the theoretically calculated minimum average error in a specific bandwidth, and the solid line is the average error when the group delay is set to a natural number (eg, 5 symbols). The coefficient of the low-pass filter 222 may be determined as a value at which the mean square error is minimized as described above. For example, referring to FIG. 3 , when the signal-to-noise ratio is 18 dB and the Doppler frequency is 5.9 Hz, the low-pass filter coefficient may be determined to be 0.125. Such information may be stored in the lookup table.

In the present disclosure, the down-sampling module 210 , the channel estimation module 220 , the equalizing module 230 , the control module 240 , and the data buffer 250 have been described as components included in the processor 200 . , according to various embodiments of the present disclosure, at least one of the down-sampling module 210 , the channel estimation module 220 and its components, the equalizing module 230 , the control module 240 , and the data buffer 250 . Some may be configured separately from the processor 200 .

4 is an exemplary view for explaining a method of controlling the communication device 100 according to various embodiments of the present disclosure.

Referring to FIG. 4 , the method 100 for controlling a communication device according to various embodiments of the present disclosure generates a data signal including an operation 400 of receiving a wireless signal and data received through the wireless signal. It may include an operation 410 of storing in the first buffer according to one delay period.

The method 100 for controlling a communication device according to various embodiments of the present disclosure includes an operation of storing a channel signal including channel estimation information on a transmission channel of the radio signal in a second buffer according to a second delay period ( 420) may be included.

The method 100 for controlling a communication device according to various embodiments of the present disclosure, based on the information related to the radio signal, determines a coefficient of a low-pass filter and a group delay associated with the low-pass filter ( 430 ) may include

The method 100 for controlling a communication device according to various embodiments of the present disclosure outputs a data signal from the first buffer, and based on the determined group delay and the first delay period, a channel stored in the second buffer It may include an operation 440 of performing equalization by outputting at least a portion of the signal.

In addition, with respect to the method 100 for controlling a communication device according to various embodiments of the present disclosure, the above-described description of the communication device 100 according to various embodiments of the present disclosure may be equally applied.

5 is an exemplary diagram for describing a communication device according to various embodiments of the present disclosure.

Referring to FIG. 5 , a communication device according to various embodiments of the present disclosure may include a transceiver 500 and a processor 510 . The processor 510 may include a matched filter 511 , an RSSI estimator 512 , a channel estimator controller 513 , a channel estimator 514 , an equalizer 515 , and a despreading/descrambling module 516 . have.

The transceiver 500 may receive a radio signal. The radio signal received through the transceiver 500 may be input to the matched filter 511 . The RSSI estimator 512 may estimate the received signal strength of the received radio signal. In FIG. 5 , the RSSI estimator 512 is illustrated as being included in the processor 50 , but according to various embodiments of the present disclosure, the RSSI estimator 512 may be provided separately from the processor 510 . have. The channel estimator controller 513 may control the channel estimator 514 . The channel estimator 514 may estimate a transmission channel through which the radio signal or the data is transmitted. The equalizer 515 may perform equalization based on a channel signal and a data signal. The despreading/descrambling module 516 may perform despreading and/or descrambling on a specific signal.

6 is an exemplary diagram for describing a channel estimator according to various embodiments of the present disclosure.

Referring to FIG. 6 , the channel estimator 610 according to various embodiments of the present disclosure may be electrically connected to the channel estimator controller 600 . The channel estimator 610 may include a down sampler 611 , a pseudo noise (PN) code generator 612 , and one or more channel estimators 613a, 613b, and 613c. In FIG. 6, the one or more channel estimators 613a, 613b, 613c is shown as a cluster 613 of channel estimators. 6 exemplarily shows a case in which parallel channel estimation is performed for n consecutive taps having a delay time difference of 1 chip interval. Accordingly, a multi-tap channel estimator having a channel estimation range of n chips is exemplified. 613a, 613b, 613c are shown. According to various embodiments of the present disclosure, n channel estimators 613a, 613b, and 613c for estimating a channel using a pilot signal corresponding to each tap may be required.

The Pseudo Noise (PN) code generator 612 generates signals such as a scrambling code, an Orthogonal Variable Spreading Factor (OVSF) code, and an antenna pattern required for despreading a signal, and then based on the generated signal. A raw signal (eg, a pilot signal) may be despread. The generated PN code is delayed by one chip and transmitted to the n channel estimators 613 , and the PN code delayed by (n - 1) chips may be transmitted to the n-th channel estimator 613c.

The channel estimator 610 may be electrically connected to the data buffer 614 , and the above-described description of the data buffer 250 may be equally applied to the data buffer 614 .

7 is an exemplary diagram for explaining any one channel estimator included in a cluster of channel estimators according to various embodiments of the present disclosure.

Referring to FIG. 7 , any one channel estimator 710 may include a despreading/descrambling module 711 and an accumulator 712 that perform despreading and/or descrambling on a received signal. The channel estimator 710 may include a low-pass filter 713 , a group delay compensation buffer 714 , and a channel weight module 715 . For the low-pass filter 713 and the group delay compensation buffer 714 , the above-described descriptions of the low-pass filter 222 and the group delay compensation buffer 224 may be equally applied. The channel weight module 715 may assign a weight calculated by the channel estimator controller 700 to the channel estimation value. The despreading/descrambling module 711 and the accumulator 712 may be electrically connected to the PN code generator 720 .

8 is an exemplary diagram for describing a channel estimator controller according to various embodiments of the present disclosure.

The channel estimator controller 800 according to various embodiments of the present disclosure may include a multi-path energy calculator 801 , a Doppler estimator 802 , and an LPF control and channel weight generation module 803 .

The multi-path energy calculator 801 may calculate energy for a channel signal or a data signal. The Doppler estimator 802 may estimate a Doppler frequency (or Doppler spread) for each of the taps. The LPF control and channel weight generation module 803 may receive information on received signal strength, for example, from the automatic gain controller, and calculate a signal-to-noise ratio for each tap.

9 is an exemplary diagram for describing an LPF control and channel weight generation module according to various embodiments of the present disclosure.

Referring to FIG. 9 , the LPF control and channel weight generation module 900 relates to information on the transmitted received signal strength and energy (in other words, multi-path energy) estimated for the data signal and the channel signal. By receiving the information, the signal-to-noise ratio and weight for each tap may be calculated. The LPF control and channel weight generation module 900 may include an averaging/scaling module 901 for averaging and/or scaling a specific signal.

The term “module” used in the present disclosure may refer to, for example, a unit including one or a combination of two or more of hardware, software, or firmware. The term “module” may be used interchangeably with terms such as, for example, unit, logic, logical block, component, or circuit. A “module” may be a minimum unit or a part of an integrally configured component. A “module” may be a minimum unit or a part of performing one or more functions. A “module” may be implemented mechanically or electronically. For example, a "module" is one of an application-specific integrated circuit (ASIC) chip, field-programmable gate arrays (FPGAs) or programmable-logic device that performs certain operations, known or to be developed in the future. It may include at least one.

At least a portion of an apparatus (eg, modules or functions thereof) or a method (eg, operations) according to various embodiments is, for example, a computer-readable storage medium in the form of a program module It can be implemented as a command stored in . When the instruction is executed by a processor (eg, the processor 320 ), the one or more processors may perform a function corresponding to the instruction. The computer-readable storage medium may be, for example, the memory 330 .

Computer-readable recording media include hard disks, floppy disks, magnetic media (eg, magnetic tape), optical media (eg, compact disc read only memory (CD-ROM), DVD ( digital versatile disc), magneto-optical media (such as floppy disk), hardware devices (such as read only memory (ROM), random access memory (RAM), or flash memory, etc.) ), etc. In addition, the program instructions may include not only machine language codes such as those generated by a compiler, but also high-level language codes that can be executed by a computer using an interpreter, etc. The above-described hardware device includes various It may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

A module or a program module according to various embodiments may include at least one or more of the above-described components, some may be omitted, or may further include additional other components. Operations performed by a module, a program module, or other components according to various embodiments may be executed sequentially, in parallel, iteratively, or in a heuristic manner. Also, some operations may be executed in a different order, omitted, or other operations may be added. And the embodiments of the present disclosure are provided for description and understanding of the disclosed, technical content, and do not limit the scope of the disclosed technology. Accordingly, the scope of the present disclosure should be construed to include all modifications or various other embodiments based on the technical spirit of the present disclosure.

100: communication device
101: transceiver
102: processor
103: memory

Claims (15)

A communication device comprising:
a transceiver configured to receive a wireless signal; and
a processor electrically coupled to the transceiver, the processor comprising:
Storing a data signal including data received through the radio signal in a first buffer according to a first delay period,
Storing a channel signal including channel estimation information on a transmission channel of the radio signal in a second buffer according to a second delay period,
determine a coefficient of a low-pass filter and a group delay associated with the low-pass filter based on the information related to the radio signal;
and performing equalization by outputting at least a portion of the channel signals stored in the second buffer based on the determined group delay and the first delay period. According to claim 1,
wherein the information related to the wireless signal includes a signal-to-noise ratio (SNR) for the wireless signal and a Doppler frequency for the wireless signal. 3. The method of claim 2,
wherein the processor estimates the signal-to-noise ratio using information about a received signal strength estimated by an automatic gain controller electrically connected to the processor. According to claim 1,
The processor, characterized in that the weight calculated based on the radio signal is given to the channel estimation information, the communication device. 5. The method of claim 4,
The processor, characterized in that the equalization is performed based on the weighted channel signal and the data signal output from the first buffer, the communication device. According to claim 1,
wherein the coefficient is a coefficient at which a mean square error (MSE) of a signal before low-pass filtering of the received radio signal and a signal after low-pass filtering of the received radio signal are minimized. According to claim 1,
The processor calculates a difference between the first delay period and the group delay, and delays and outputs the channel signal according to a time corresponding to a result of calculating the difference between the first delay period and the group delay. 2 A communication device, characterized in that it controls the buffer. According to claim 1,
The first delay period is characterized in that it has a larger value than the second delay period, the communication device. In the control method of a communication device (communication device),
receiving a radio signal; and
storing a data signal including data received through the radio signal in a first buffer according to a first delay period;
storing a channel signal including channel estimation information on a transmission channel of the radio signal in a second buffer according to a second delay period;
determining, based on the information related to the radio signal, coefficients of a low-pass filter and a group delay related to the low-pass filter;
and performing equalization by outputting at least a portion of the channel signals stored in the second buffer based on the determined group delay and the first delay period. 10. The method of claim 9,
The method for controlling a communication device, characterized in that the information related to the radio signal includes a signal-to-noise ratio (SNR) for the radio signal and a Doppler frequency for the radio signal. 11. The method of claim 10,
The method of claim 1, further comprising the step of estimating the signal-to-noise ratio using the information on the received signal strength estimated by the automatic gain controller. 10. The method of claim 9,
The method of controlling a communication device, characterized in that it further comprises the step of assigning a weight calculated based on the radio signal to the channel estimation information. 13. The method of claim 12,
The method for controlling a communication device, further comprising: performing the equalizing based on the weighted channel signal and the data signal output from the first buffer. 10. The method of claim 9,
Wherein the coefficient is a coefficient in which a mean square error (MSE) of a signal before low-pass filtering of the received radio signal and a signal after low-pass filtering of the received radio signal is minimized. 10. The method of claim 9,
calculating a difference between the first delay period and the group delay;
and delaying the channel signal according to a time corresponding to a result of calculating the difference between the first delay period and the group delay and outputting the channel signal from the second buffer.

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