KR20190052649A - Method and apparatus for transmitting and receiving synchronizing signal in a communication system - Google Patents

Abstract

Disclosed is a method for transmitting and receiving a synchronizing signal in a communication system. The method comprises the steps of: generating a base sequence; generating a transforming sequence by inverting polarity of the base sequence; and transmitting a synchronizing signal including the base sequence and the transforming sequence through a frequency band. Each of the base sequence and the transforming sequence is mapped to at least one of a first frequency region with a frequency lower than a DC subcarrier and a second frequency region with a frequency higher than the DC subcarrier in the frequency band.

Description

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

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synchronous signal transmission and reception technique, and more particularly, to a synchronous signal transmission and reception method and apparatus for efficiently estimating synchronization in a communication system having a frequency offset.

In order to perform communication with the base station, the terminal can search for a cell in the network. The base station may transmit a synchronization signal including a base sequence for synchronization estimation. The terminal can acquire time / frequency synchronization by receiving a synchronization signal from the base station. For example, the UE can estimate the time synchronization by measuring the reception correlation of the synchronization signal. In order to measure the reception correlation of the synchronous signal, the terminal can perform a complex operation. This complex calculation can increase the complexity of the synchronization estimation method.

In the communication system, a frequency offset, which is an error between the frequency of the transmission signal of the base station and the frequency of the reception signal of the terminal, may affect the synchronization signal of the base station. The conventional synchronization estimation method based on a synchronization signal has a problem in that the synchronization estimation performance of the terminal deteriorates as the frequency offset of the synchronization signal becomes larger.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and an apparatus for transmitting and receiving a synchronization signal for improving synchronization estimation performance of a terminal in a communication system having a frequency offset.

According to an aspect of the present invention, there is provided a method of designing a wireless transmission signal, the method comprising: generating a base sequence; Inverting the polarity of the base sequence to generate a modified sequence; And transmitting the synchronization signal including the base sequence and the deformation sequence through a frequency band, wherein the base sequence and the deformation sequence each comprise a first frequency band having a frequency lower than a DC sub- Or a second frequency domain having a higher frequency than the DC subcarrier.

A base station in a method of transmitting and receiving a synchronization signal according to the present invention can transmit a synchronization signal including a base sequence and a deformation sequence whose polarity of the base sequence is inverted.

A terminal of a method for transmitting and receiving a synchronization signal according to the present invention can estimate synchronization with improved performance based on a synchronization signal including a base sequence and a modification sequence.

1 is a conceptual diagram showing a first embodiment of a communication network.
2 is a block diagram illustrating a first embodiment of a communication node in a communication network;
3 is a conceptual diagram showing a first embodiment of a PSS sequence mapping method.
4 is a conceptual diagram showing a second embodiment of the PSS sequence mapping method.
5 is a flowchart illustrating a method of mapping a sequence element to a slot of a radio frame.
6 is a conceptual diagram showing a third embodiment of the PSS sequence mapping method.
7 is a conceptual diagram showing a fourth embodiment of the PSS sequence mapping method.
8 is a conceptual diagram showing a fifth embodiment of the PSS sequence mapping method.
9 is a conceptual diagram showing an embodiment of a control sequence and a data sequence mapping method.
10 is a flowchart showing an embodiment of the SSS sequence mapping method.
11 is a conceptual diagram showing an embodiment of the SSS sequence mapping method.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

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

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the relevant art and are to be interpreted in an ideal or overly formal sense unless explicitly defined in the present application Do not.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In order to facilitate the understanding of the present invention, the same reference numerals are used for the same constituent elements in the drawings and redundant explanations for the same constituent elements are omitted.

1 is a conceptual diagram showing a first embodiment of a communication network.

1, a communication network 100 includes a plurality of communication nodes 110-1, 110-2, 110-3, 120-1, 120-2, 130-1, 130-2, 130-3, 130-4, 130-5, and 130-6. Each of the plurality of communication nodes may support at least one communication protocol. For example, each of the plurality of communication nodes may be a wireless communication device based on a communication protocol based on a code division multiple access (CDMA) communication protocol, a communication protocol based on a wideband CDMA (WCDMA), a communication protocol based on a time division multiple access (TDMA) based communication protocol, an orthogonal frequency division multiplexing (OFDM) based communication protocol, an OFDMA (orthogonal frequency division multiple access) based communication protocol, a single carrier-FDMA based communication protocol, a non-orthogonal multiple access-based communication protocol, and a space division multiple access (SDMA) -based communication protocol. Each of the plurality of communication nodes may have the following structure.

2 is a block diagram illustrating communication nodes in a communication network;

Referring to FIG. 2, the communication node 200 may include at least one processor 210, a memory 220, and a transceiver 230 connected to the network to perform communication. The communication node 200 may further include an input interface device 240, an output interface device 250, a storage device 260, and the like. Each component included in the communication node 200 may be connected by a bus 270 and communicate with each other.

The processor 210 may execute a program command stored in at least one of the memory 220 and the storage device 260. The processor 210 may refer to a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which methods in accordance with embodiments of the present invention are performed. Each of the memory 220 and the storage device 260 may be constituted of at least one of a volatile storage medium and a nonvolatile storage medium. For example, the memory 220 may comprise at least one of read-only memory (ROM) and random access memory (RAM).

In the LTE communication system, one radio frame may be composed of 10 subframes, and one subframe may be composed of 2 slots.

One slot may have a plurality of OFDM symbols in the time domain, and may include a plurality of subcarriers in the frequency domain. For example, one slot may have six OFDM symbols (in case of an extended cyclic prefix) or seven OFDM symbols (in case of a normal cyclic prefix), and may have 12 subcarriers in the frequency domain. The time-frequency domain defined by one slot may be referred to as a resource block (RB).

A subframe can be divided into a control area and a data area. A PDCCH (Physical Downlink Control Channel) may be allocated to the control region. A PDSCH (Physical Downlink Shared Channel) may be allocated to the data area.

Some of the sub-frames may be special sub-frames. The special subframe may include a downlink pilot time slot (DwPTS), a guard period (GP), and an uplink pilot time slot (UpPTS). The DwPTS can be used for time and frequency synchronization estimation and cell search of the UE. The GP is a section for eliminating the interference caused by the multipath delay of the downlink signal.

The synchronization signal, which is information necessary for cell ID estimation and time / frequency synchronization, may be mapped to the DwPTS. The synchronization signal may include a primary synchronization signal (PSS) and a secondary synchronization signal (SSS).

In order to perform communication with the base station, the terminal can acquire time and frequency synchronization from the synchronization signal of the downlink signal received from the base station. The PSS may indicate time synchronization information such as OFDM symbol synchronization, frequency synchronization information, and cell ID information in a group, and the SSS may indicate frame synchronization and cell group ID information.

The PSS may be mapped to two OFDM symbols of one subframe, and the SSS may be mapped to two OFDM symbols of one subframe to which the PSS is not mapped. And the positions of the PSS and the SSS in the time domain in the frame may be different depending on the division method of the cell.

Specifically, in the case of Frequency Division Duplex (FDD), the PSS may be mapped to the last OFDM symbol of the first slot of subframes 0 and 5 and transmitted. The SSS may be mapped to the second OFDM symbol at the end of the first slot of subframes 0 and 5 and transmitted. In the case of TDD (Time Division Duplex), the PSS can be mapped to the third symbol of subframes 1 and 6 and transmitted. The SSS may be mapped to the last symbol of the subframes 0 and 5 and transmitted.

FIG. 3 is a conceptual diagram showing a first embodiment of a PSS sequence mapping method, and FIG. 4 is a conceptual diagram showing a second embodiment of a PSS sequence mapping method.

으로 표현될 수 있다. Referring to FIG. 3 and FIG. 4, a scheme of mapping a PSS sequence to a slot of a radio frame is as follows. The PSS in FIGS. 3 and 4 can occupy a plurality of subcarriers that are available frequency resources. The total number of sub-carriers that the PSS can use is

. ≪ / RTI >

로 표현될 수 있다. PSS의 시퀀스 길이

는 슬롯의 총 주파수 자원의 개수

와 동일할 수 있으며, 슬롯의 총 주파수 자원의 개수

보다 작을 수 있다.The base station may map the sequence of the PSS to one slot of the radio frame. In this case, the length of the PSS sequence is

. ≪ / RTI > Sequence length of PSS

Is the number of total frequency resources of the slot

And the number of total frequency resources of the slot

.

개의 부반송파에 PSS를 매핑할 수 있다. 예를 들어 PSS가 길이 63의 시퀀스인 경우 기지국은 슬롯의 가운데에 위치하는 63개의 부반송파에 PSS를 매핑할 수 있다. 이 때 기지국은 슬롯의 전체 대역 중 PSS가 매핑되지 않은 부반송파에 0을 할당할 수 있다. Specifically, the base station is located in the center of the entire band of the slot

PSS can be mapped to the subcarriers. For example, if the PSS is a sequence of length 63, the base station can map the PSS to 63 subcarriers located in the middle of the slot. At this time, the base station can allocate 0 to the sub-carriers to which the PSS is not mapped among the entire bandwidth of the slot.

)를 가지는 부반송파일 수 있다. 기지국은 DC 부반송파에 PSS의 시퀀스의 엘리먼트를 매핑할 수 있으며, 매핑하지 않을 수도 있다. 도 3의 실시예는 DC 부반송파에 하나의 시퀀스 엘리먼트가 매핑된 경우이며, 도 4의 실시예는 DC 부반송파에 시퀀스 엘리먼트가 매핑되지 않은 경우일 수 있다.One of the plurality of subcarriers of the slot may be a direct carrier (DC) subcarrier. A DC subcarrier is a center frequency of a plurality of subcarriers of a slot

). ≪ / RTI > The base station may or may not map the elements of the sequence of the PSS to the DC subcarriers. The embodiment of FIG. 3 is a case where one sequence element is mapped to a DC subcarrier, and the embodiment of FIG. 4 may be a case where a sequence element is not mapped to a DC subcarrier.

The PSS sequence that is mapped to the frequency domain of the slot may be in the form of a complex sequence and may be in the form of a binary sequence. However, the form of the PSS sequence is not limited to the range described in this specification.

According to an embodiment of the present invention, the PSS sequence mapped to the frequency domain of the slot may be a Zadoff-Chu (ZC) sequence. The PSS sequence mapped to a plurality of subcarriers can be expressed as Equation (1).

In Equation (1), u indicates the sequence index of the PSS sequence, and k indicates the sequence element index of the PSS sequence.

을 매핑하고 주파수가 낮은 순서대로

까지 매핑할 수 있다. 또는 기지국은 DC 부반송파에

을 매핑하고 주파수가 낮은 순서대로

까지 매핑한 후 나머지 시퀀스 엘리먼트를 가장 높은 주파수를 가지는 부반송파부터 순서대로 매핑할 수 있다. Referring to FIG. 3, the base station transmits the highest frequency subcarrier

And in order of decreasing frequency

. Alternatively, the base station may transmit

And in order of decreasing frequency

And the remaining sequence elements can be mapped in order from the highest frequency subcarrier.

을 매핑하고 DC 부반송파를 제외한 부반송파에 순차적으로

까지 매핑할 수 있다. 또한 기지국은 DC 부반송파보다 낮은 주파수를 가지는 부반송파 중 가장 높은 주파수를 가지는 부반송파에

을 매핑하고 순차적으로

까지 매핑한 후 나머지 시퀀스 엘리먼트를 가장 높은 주파수를 가지는 부반송파로부터 순서대로 매핑할 수 있다. Referring to FIG. 4, a Node B transmits a sub-carrier having a highest frequency among sub-

To the subcarriers except for the DC subcarriers.

. In addition, the base station transmits a subcarrier having the highest frequency among the subcarriers having a lower frequency than the DC subcarrier

And sequentially

And the remaining sequence elements can be mapped in order from the subcarrier having the highest frequency.

The base station can map and transmit the base sequence of the synchronization signal, and the terminal receiving the synchronization signal can measure the reception correlation value of the synchronization signal. As a result of measuring the correlation value between the synchronization signal and the cell ID, the terminal can regard the sample time offset (STO) when the correlation value has the highest value as a time synchronization point.

A problem with the prior art is that the synchronization estimation performance may be degraded if the frequency offset of the radio signal is severe.

When a complex sequence is mapped to a subcarrier, the terminal receiving the synchronization signal can perform a complex multiplication operation on the sequence of the synchronization signal to measure the reception correlation value of the synchronization signal. The terminal may perform a complex operation such as a complex operation in order to measure a received correlation value of a synchronous signal of a signal.

FIG. 5 is a flowchart illustrating a method of mapping a sequence element to a slot of a radio frame, and FIGS. 6 to 8 are conceptual diagrams illustrating third to fifth embodiments of the PSS sequence mapping method.

5 to 8, a method of mapping a sequence of PSS according to the present invention is as follows.

)를 가지는 부반송파일 수 있다.One of the plurality of subcarriers of the slot to which the PSS is mapped may be a DC subcarrier. The DC subcarriers may be subcarriers for which the sequence elements are not mapped. A DC subcarrier is a subcarrier having a center frequency (

). ≪ / RTI >

A slot of a radio frame to which a synchronization signal is mapped may be divided into two frequency regions (for example, a first frequency region and a second frequency region). A plurality of subcarriers may be classified based on a DC subcarrier. For example, a base station may define a set of subcarriers having a lower frequency than a DC subcarrier among a plurality of subcarriers as a first frequency domain, and a set of subcarriers having a frequency higher than a DC subcarrier as a second frequency domain.

일 경우, 제2 주파수 영역의 부반송파 개수 역시

일 수 있다. The number of subcarriers in the first frequency domain and the number of subcarriers in the second frequency domain may be the same. For example, if the number of subcarriers in the first frequency domain is the length of the base sequence

, The number of subcarriers in the second frequency domain is also

Lt; / RTI >

일 수 있다. 기지국은 무선 프레임의 슬롯에 베이스 시퀀스

를 매핑할 수 있다(S510). 기지국은 슬롯의 두 주파수 영역 중 하나에 베이스 시퀀스를 매핑할 수 있다. 예를 들어 기지국은 슬롯의 주파수 영역 중 제1 주파수 영역의 부반송파에 베이스 시퀀스를 매핑할 수 있다(S510). The PSS may be in the form of combining a plurality of sequences. One of the plurality of sequences constituting the PSS is a base sequence

Lt; / RTI > The base station transmits a base sequence

(S510). The base station may map the base sequence to one of the two frequency regions of the slot. For example, the base station may map a base sequence to a subcarrier in a first frequency region of a frequency region of a slot (S510).

는 수학식 2와 같이 표현될 수 있다. The base sequence constituting the PSS may be a complex sequence, and the complex sequence may be a ZC sequence. When the base sequence is a ZC sequence, the base sequence constituting the PSS

Can be expressed by Equation (2).

는 베이스 시퀀스의 길이를 의미할 수 있다. 5 and Equation 2, V denotes a sequence index of a base sequence, k denotes an element index of a base sequence,

May denote the length of the base sequence.

은 제1 주파수 영역의 부반송파 중 가장 큰 주파수를 가지는 부반송파에 매핑될 수 있으며,

은 제1 주파수 영역의 부반송파 중 가장 작은 주파수를 가지는 부반송파에 매핑될 수 있다. The base station may map each element of the base sequence according to the frequency magnitude of the subcarriers of the slot. E.g,

May be mapped to subcarriers having the largest frequency among the subcarriers in the first frequency domain,

May be mapped to subcarriers having the smallest frequency among subcarriers in the first frequency domain.

가 결합된 구성일 수 있다. 기지국은 베이스 시퀀스에 기초하여 베이스 시퀀스와 별도의 시퀀스인 변형 시퀀스

를 생성할 수 있다(S520). 기지국은 미리 설정된 연산을 수행하여 베이스 시퀀스

의 시퀀스 엘리먼트로부터 변형 시퀀스

의 시퀀스 엘리먼트를 생성할 수 있다.PSS is the base sequence And the transformation sequence

May be a combined configuration. The base station generates a base sequence based on the base sequence and a deformation sequence

(S520). The base station performs a predetermined operation to generate a base sequence

Lt; RTI ID = 0.0 >

Lt; / RTI >

를 생성하기 위하여 기지국은 베이스 시퀀스

엘리먼트의 실수부 및 허수부 중 적어도 하나의 극성을 반전할 수 있다. According to one embodiment of the present invention,

The base station transmits the base sequence < RTI ID = 0.0 >

The polarity of at least one of the real part and the imaginary part of the element can be reversed.

According to the embodiment of FIG. 6, the base station may perform an operation of Equation (3) to generate a deformation sequence from the base sequence (S520). The * operator in Equations 3 to 4 means the conjugate operator.

In the case of the embodiment of FIG. 6, the base station may generate a deformation sequence by inverting the polarity of the imaginary part of each base sequence element (S520). The synchronous signal designed as described above may be a signal composed of real parts only in the time domain.

According to the embodiment of FIG. 7, the base station may perform an operation of Equation (4) to generate a deformation sequence from the base sequence (S520).

In the case of the embodiment of FIG. 7, the base station may reverse the polarity of the real part of the element of the base sequence to generate a modified sequence (S520). The synchronous signal designed as described above may be a signal composed of only the imaginary part in the time domain.

According to the embodiment of FIG. 8, the base station may perform an operation of Equation (5) to generate a deformation sequence from the base sequence.

In the case of the embodiment of FIG. 8, the base station may generate a deformation sequence by inverting the polarity of the real and imaginary parts of the element of the base sequence.

를 매핑할 수 있다(S530). 구체적으로 기지국은 슬롯의 부반송파 중 베이스 시퀀스가 매핑되지 않은 주파수 영역에 변형 시퀀스를 매핑할 수 있다. 베이스 시퀀스가 주파수 대역 중 제1 주파수 영역에 매핑된 경우, 기지국은 주파수 대역 중 제2 주파수 영역에 변형 시퀀스

를 매핑할 수 있다(S530).The base station transmits a deformation sequence to a subcarrier of a slot of a radio frame

(S530). Specifically, the base station may map the deformation sequence to a frequency region to which the base sequence is not mapped among the subcarriers of the slot. When the base sequence is mapped to the first frequency region of the frequency band, the base station transmits a deformation sequence

(S530).

When the base station maps the deformation sequence to the second frequency domain, the base station may map the deformation sequence so that the sequence element index of the base sequence and the sequence element index of the deformation sequence are symmetrical with respect to the DC subcarrier (S530).

는 제1 주파수 영역의 부반송파 중 가장 큰 주파수를 가지는 부반송파에 매핑될 수 있으며,

은 제1 주파수 영역의 부반송파 중 가장 작은 주파수를 가지는 부반송파에 매핑될 수 있다. 이 경우

는 제2 주파수 영역의 부반송파 중 가장 작은 주파수를 가지는 부반송파에 매핑될 수 있으며,

은 제2 주파수 영역의 부반송파 중 가장 큰 주파수를 가지는 부반송파에 매핑될 수 있다.E.g,

May be mapped to subcarriers having the largest frequency among the subcarriers in the first frequency domain,

May be mapped to subcarriers having the smallest frequency among subcarriers in the first frequency domain. in this case

May be mapped to subcarriers having the smallest frequency among the subcarriers in the second frequency domain,

May be mapped to subcarriers having the largest frequency among the subcarriers in the second frequency domain.

The two PSSs within a radio frame within a cell may be identical to each other. The PSS of one cell may have different values according to the physical layer cell ID of the cell.

The MS may map a base sequence and a sequence of the PSS to a sequence corresponding to the cell ID by selecting a sequence that satisfies a preset condition and a correlation characteristic level of the cell ID. For example, when three sequences having a sequence index v = 0, 1, 2 are determined based on the correlation characteristic level of the base sequence, the first cell group ID may be mapped to a sequence having a sequence index v = 0. The UE can map the second cell group ID to the base sequence having the sequence index v = 1 and map the third cell group ID to the base sequence having the sequence index v = 2.

The method of mapping a sequence to a slot of the radio frame disclosed in FIG. 5 may not be limited to the purpose of mapping the PSS.

9 is a conceptual diagram showing an embodiment in which a control sequence and a data sequence are mapped. Referring to FIG. 5 and FIG. 9, a method of mapping a sequence to a control area of a signal and a slot of a data area according to the present invention is as follows.

One subcarrier of the plurality of subcarriers of the PDCCH and the PDSCH may be a DC subcarrier. The DC subcarrier may be a subcarrier having a center frequency among a plurality of subcarriers in the control domain and the data domain. The DC subcarriers may be subcarriers for which the sequence elements are not mapped.

The frequency band to which the signal is mapped may be divided into two frequency regions (for example, a first frequency region and a second frequency region). A plurality of subcarriers may be classified based on a DC subcarrier. For example, a base station may define a set of subcarriers having a lower frequency than a DC subcarrier among a plurality of subcarriers as a first frequency domain, and a set of subcarriers having a frequency higher than a DC subcarrier as a second frequency domain.

일 경우, 제2 주파수 영역의 부반송파 개수 역시

일 수 있다.The number of subcarriers in the first frequency domain and the number of subcarriers in the second frequency domain may be the same. For example, if the number of subcarriers in the first frequency domain is the length of the control and data sequence

, The number of subcarriers in the second frequency domain is also

Lt; / RTI >

를 매핑할 수 있으며, 제어 영역 중 하나의 주파수 영역에 제어 시퀀스를 매핑할 수 있다. 예를 들어, 기지국은 제어 영역의 제1 주파수 영역에 제어 시퀀스를 매핑할 수 있다. The base station transmits a control sequence

And the control sequence can be mapped to one frequency region of the control region. For example, the base station may map the control sequence to the first frequency region of the control region.

를 매핑할 수 있으며, 데이터 영역 중 하나의 주파수 영역에 데이터 시퀀스를 매핑할 수 있다. 예를 들어, 기지국은 데이터 영역의 제1 주파수 영역에 데이터 시퀀스를 매핑할 수 있다.The base station transmits a data sequence

And can map the data sequence to one frequency region of the data region. For example, the base station may map the data sequence to a first frequency region of the data region.

The control sequence mapped to the control region may be a complex sequence and may be a binary sequence. Also, the data sequence mapped to the data area may be a complex sequence and may be a binary sequence. However, the control sequence is not limited to the range described in the specification, which corresponds to the data sequence.

Hereinafter, it will be assumed that the control sequence mapped to the control region is a complex sequence.

은 제1 주파수 영역의 부반송파 중 가장 높은 주파수를 가지는 부반송파에 매핑될 수 있으며,

은 제1 주파수 영역의 부반송파 중 가장 낮은 주파수를 가지는 부반송파에 매핑될 수 있다. Each sequence element of the control sequence may be mapped according to the frequency of the subcarrier. E.g,

May be mapped to subcarriers having the highest frequency among the subcarriers in the first frequency domain,

May be mapped to subcarriers having the lowest frequency among the subcarriers in the first frequency domain.

를 생성할 수 있다. 기지국은 미리 설정된 연산을 수행하여 제어 시퀀스

의 시퀀스 엘리먼트로부터 변형 시퀀스

의 시퀀스 엘리먼트를 생성할 수 있다.The base station generates a control sequence based on the control sequence and a deformation sequence

Lt; / RTI > The base station performs a pre-set operation to generate a control sequence

Lt; RTI ID = 0.0 >

Lt; / RTI >

를 생성하기 위하여 기지국은 제어 시퀀스

의 시퀀스 엘리먼트의 실수부 및 허수부 중 적어도 하나의 극성을 반전할 수 있다. According to one embodiment of the present invention,

The base station transmits a control sequence < RTI ID = 0.0 >

It is possible to invert the polarity of at least one of the real part and the imaginary part of the sequence element of the sequence element.

According to an embodiment of the present invention, the base station may perform an operation of Equation (6) to generate a deformation sequence from the control sequence.

The base station can reverse the polarity of the imaginary part of the sequence element of the control sequence to produce a modified sequence. The frequency domain control signal and the signal having only the real part in the time domain of the data signal.

According to another embodiment of the present invention, the base station may perform an operation of Equation (7) to generate a modified sequence from the control sequence.

The base station can reverse the polarity of the real part of the sequence element of the control sequence to generate a deformation sequence. The frequency domain control signals and data signals designed as described above may be signals having only imaginary parts in the time domain.

According to another embodiment of the present invention, the base station can perform the operation of Equation (8) to generate a modified sequence.

The base station can reverse the polarity of the real part and the imaginary part of the sequence element of the control sequence to generate a modified sequence.

를 매핑할 수 있다. 구체적으로 기지국은 제어 시퀀스가 매핑되지 않은 주파수 영역에 변형 시퀀스를 매핑할 수 있다. 제어 데이터 시퀀스가 제1 주파수 영역에 매핑된 경우, 기지국은 슬롯의 부반송파 중 제2 주파수 영역에 변형 시퀀스

를 매핑할 수 있다.The base station may be configured to perform a deformation sequence on a plurality of sub-

Can be mapped. Specifically, the base station may map the deformation sequence to a frequency region to which the control sequence is not mapped. When the control data sequence is mapped to the first frequency domain, the base station transmits the deformation sequence in the second frequency domain of the sub-

Can be mapped.

When the base station maps the deformation sequence to the second frequency domain, the base station may map the deformation sequence to the second frequency domain so that the sequence element index of the control sequence and the sequence element index of the deformation sequence are symmetrical with respect to the DC subcarrier have.

은 제1 주파수 영역의 부반송파 중 가장 큰 주파수를 가지는 부반송파에 매핑될 수 있으며,

은 제1 주파수 영역의 부반송파 중 가장 작은 주파수를 가지는 부반송파에 매핑될 수 있다. 이 경우

은 제2 주파수 영역의 부반송파 중 가장 작은 주파수를 가지는 부반송파에 매핑될 수 있으며,

은 제2 주파수 영역의 부반송파 중 가장 큰 주파수를 가지는 부반송파에 매핑될 수 있다.E.g,

May be mapped to subcarriers having the largest frequency among the subcarriers in the first frequency domain,

May be mapped to subcarriers having the smallest frequency among subcarriers in the first frequency domain. in this case

May be mapped to subcarriers having the smallest frequency among the subcarriers in the second frequency domain,

May be mapped to subcarriers having the largest frequency among the subcarriers in the second frequency domain.

In this specification, a method of mapping a control sequence to a control region has been described, but it will be obvious that the above description can be applied to a method of mapping a data sequence. It will also be appreciated that the method of mapping the sequences described herein may be applied to mapping control sequences and data sequences as well as other sequences.

FIG. 10 is a flowchart illustrating a method of mapping an SSS sequence element, and FIG. 11 is a conceptual diagram illustrating an embodiment in which a sequence element of an SSS is mapped.

10 and 11, the base station can map a sequence of SSSs to one slot of a radio frame as follows.

One of the sub-carriers of the slot to which the SSS is mapped may be a DC sub-carrier. The DC subcarrier may be a subcarrier having a center frequency among the subcarriers of the slot. The DC subcarriers may be subcarriers for which the sequence elements are not mapped.

를 매핑할 수 있다(S1050).

는 서로 다른 복수개의 시퀀스들이 결합된 구성일 수 있다. 구체적으로

복수개의 시퀀스들의 수학적 곱셈으로 구성될 수 있다. 본 발명의 일 실시예에 따른

는 수학식 9와 같이 표현될 수 있다. The base station transmits a sequence of SSSs to the sub-

(S1050).

May be a configuration in which a plurality of sequences different from each other are combined. Specifically

And may comprise a mathematical multiplication of a plurality of sequences. According to one embodiment of the present invention

Can be expressed by Equation (9).

는

시퀀스,

시퀀스 및

시퀀스의 수학적 결합으로 생성될 수 있다. According to equation (9)

The

sequence,

Sequence and

May be generated by a mathematical combination of sequences.

시퀀스를 생성할 수 있다(S1010). SSS 시퀀스의

시퀀스는 이진 골드 시퀀스일 수 있다. SSS 시퀀스의 이진 골든 시퀀스는 사이클릭 확장된(cyclic-extended) 시퀀스일 수 있다. 예를 들어 SSS 시퀀스의

시퀀스는 길이가 61인 이진 골드 시퀀스 중 하나의 엘리먼트가 사이클릭 확장되어 길이가 62인 시퀀스일 수 있다.The base station

A sequence can be generated (S1010). Of the SSS sequence

The sequence may be a binary gold sequence. The binary golden sequence of the SSS sequence may be a cyclic-extended sequence. For example, in the SSS sequence

The sequence may be a sequence of length 62, with one element of the binary gold sequence of length 61 cyclically extended.

The sequence index x of the binary gold sequence can identify the cell ID. Specifically, the sequence index x can identify the cell group ID, and according to an embodiment of the present invention, the sequence index x can identify 56 cell group IDs.

시퀀스를 생성할 수 있다(S1020). SSS 시퀀스의

시퀀스는 Hadamard 시퀀스일 수 있다. SSS 시퀀스의 Hadamard 시퀀스는 시퀀스 엘리먼트의 일부가 제외(truncated)된 시퀀스일 수 있다. 예를 들어, SSS 시퀀스의 Hadamard 시퀀스는 길이 64의 시퀀스 중 마지막 2개의 시퀀스 엘리먼트가 삭제된 길이가 62인 시퀀스일 수 있다.The base station

A sequence can be generated (S1020). Of the SSS sequence

The sequence may be a Hadamard sequence. The Hadamard sequence of the SSS sequence may be a sequence in which a portion of the sequence element is truncated. For example, the Hadamard sequence of the SSS sequence may be a sequence of length 62, of which the last two sequence elements of the sequence of length 64 are deleted.

The sequence index q of the Hadamard sequence can identify the cell group ID. Specifically, the sequence index q can identify the cell group ID. According to an embodiment of the present invention, the sequence index q can distinguish three cell group IDs.

 The sequence index z of the Hadamard sequence can be used to distinguish different synchronous signals. When a terminal receives two or more synchronization signals in a frame, the terminal can distinguish suitable synchronization signals from two or more synchronization signals based on the sequence index z. For example, the UE can distinguish the SSS mapped to the 0th subframe and the 5th subframe based on the sequence index z of the SSS. Accordingly, the terminal can acquire the start point frame of two subframes.

을 매핑할 때, (q,z)가 (0,1)에 Hadamard 시퀀스 중

을 매핑할 수 있다. The sequence index z may serve to increase the physical ID indicated by the Hadamard sequence. For example, if the index pair (q, z) is at (0,0) and the Hadamard sequence

(Q, z) is (0, 1) in the Hadamard sequence

Can be mapped.

시퀀스를 생성할 수 있다(S1020). SSS 시퀀스의

은 푸리에 급수 시퀀스일 수 있다. 푸리에 급수 시퀀스

는 인접 셀간 간섭을 평준화하기 위한 스크램블링을 수행할 수 있다. SSS 시퀀스의 푸리에 급수 시퀀스

은 다음 식과 같이 표현될 수 있다. The base station

A sequence can be generated (S1020). Of the SSS sequence

May be a Fourier series. Fourier series

May perform scrambling to level the inter-cell interference. Fourier series of SSS sequences

Can be expressed by the following equation.

의 시퀀스 인덱스 p 역시 0일 수 있다.The sequence index p of the Fourier series of Equation 10 may be mapped to the sequence index v of the PSS sequence of Figs. For example, if the sequence index v of the PSS is 0, the Fourier sequence

≪ / RTI > may also be zero.

는 PSS 시퀀스의 시퀀스 인덱스 v와 일대일 대응관계일 수 있다. 예를 들어 시퀀스 인덱스 v가 각각 0,1,2 일 경우 푸리에 시퀀스

는 각각 0, 16, 48일 수 있다. 시퀀스 인덱스 v에 대응되는

의 값은 푸리에 시퀀스의 크기에 따라 다르게 설정될 수 있다. The Fourier sequence of equation

May be a one-to-one correspondence with the sequence index v of the PSS sequence. For example, if the sequence index v is 0, 1, and 2, respectively, the Fourier sequence

Can be 0, 16, and 48, respectively. Corresponding to the sequence index v

May be set differently depending on the size of the Fourier sequence.

시퀀스,

시퀀스 및

시퀀스를 결합하여

시퀀스를 생성할 수 있다(S1040). The base station

sequence,

Sequence and

By combining sequences

A sequence can be generated (S1040).

The base station may map the SSS sequence to the slot according to the frequency of the subcarrier (S1050). Specifically, the base station can map the SSS sequence to the center of the entire band of the slot to which the SSS is mapped. For example, if the SSS sequence is a sequence of length 63, the base station may map the SSS sequence to 63 subcarriers located in the middle of the subcarriers of the slot.

을 매핑할 수 있고 DC 부반송파를 제외한 부반송파에 순차적으로

시퀀스의 엘리먼트를 매핑할 수 있다. For example, a base station may transmit a subcarrier having the highest frequency

Can be mapped and subcarriers other than DC subcarriers can be sequentially

You can map elements of a sequence.

부터

까지의 시퀀스 엘리먼트를 순차적으로 매핑할 수 있고 DC 부반송파보다 높은 주파수를 가지는 부반송파 영역에

부터

까지 순차적으로 시퀀스 엘리먼트를 할당할 수 있다. According to another embodiment, the base station may allocate a subcarrier having a frequency lower than a DC subcarrier

from

Can be sequentially mapped to a subcarrier region having a higher frequency than a DC subcarrier

from

The sequence elements can be sequentially allocated up to.

의 시퀀스 인덱스 x와 q는 수학식 11에 의해 결정될 수 있다. The physical cell group ID (PCGI) that can be distinguished based on the sequence indices x and q except for the sequence index z for frame synchronization and the sequence index q for scrambling may be 168. From PCGI

Can be determined by Equation (11).

In Equation (11), mod (y, 56) is a modulo operator which means the remainder when y is divided by 56, and [y] is an operator denoting the integer part of y.

Referring to FIGS. 5 and 10, a method for estimating synchronization of a terminal receiving a synchronization signal according to an embodiment of the present invention will be described.

A method for the UE to acquire time synchronization and frequency synchronization and cell ID information from a synchronization signal including a PSS and an SSS may include acquiring a cell ID in the group from the PSS and acquiring the cell group ID from the SSS .

Specifically, the total number of cell IDs to be distinguished by the UE in the LTE wireless communication may be 504. The terminal can determine one of the three cell IDs in the step of acquiring the cell ID in the specific cell group from the PSS. Also, the terminal can determine one of 168 cell group IDs in the step of acquiring the cell group ID from the SSS.

The step of acquiring the cell ID from the PSS may include a step S540 of specifying a correlation value between the cell ID and the PSS and a step S550 of estimating the time synchronization. The UE can acquire the cell ID information in the group in the step of acquiring the cell ID from the PSS.

The step of acquiring the physical ID from the SSS may estimate the starting point of the SSS based on the time synchronization acquired in acquiring the cell ID from the PSS. For example, the UE can estimate one subframe among the 0th subframe or the 5th subframe in which the SSS is recorded based on the STO value obtained in the step of acquiring the cell ID from the PSS as the start point of the SSS.

를 구성하는 복수개의 시퀀스 각각을 복호화할 수 있다. 본 발명의 일 실시예에 따르면, SSS로부터 물리 ID를 획득하는 단계에서 단말은 푸리에 시퀀스 복호화 단계(S1060), Hadamard 시퀀스 복호화 단계(S1070) 및 이진 골드 시퀀스 복호화 단계(S1080)를 수행하여 셀 ID를 추정할 수 있다. In acquiring the physical ID from the SSS,

It is possible to decode each of the plurality of sequences constituting the sequence. According to an embodiment of the present invention, in the step of acquiring the physical ID from the SSS, the terminal performs the Fourier sequence decoding step (S1060), the Hadamard sequence decoding step (S1070), and the Binary Gold Sequence decoding step (S1080) Can be estimated.

According to another embodiment of the present invention, a method of acquiring time synchronization, frequency synchronization and cell ID information from a synchronization signal from a terminal can acquire a cell group ID and a cell ID in a group from the SSS.

의 인덱스 p와 PSS를 구성하는 베이스 시퀀스의 시퀀스 인덱스 v가 일대일 대응될 경우, 단말은 푸리에 시퀀스

를 복호화한 결과 푸리에 시퀀스와 대응하는 PSS의 시퀀스에 기초하여 신호의 시간 동기와 SSS의 시작 지점을 추정할 수 있다.The terminal may receive the SSS and decode the Fourier sequence of the SSS (S1060). The Fourier sequence constituting the SSS

And the sequence index v of the base sequence constituting the PSS corresponds to one-to-one correspondence, the terminal transmits the Fourier sequence

The time synchronization of the signal and the starting point of the SSS can be estimated based on the sequence of the PSS corresponding to the Fourier sequence.

Based on the time synchronization of the estimated signal and the starting point of the SSS, the terminal can acquire the cell group ID by performing the Hadamard sequence decoding step (S1070) and the binary Gold sequence decoding step (S1080).

를 구성하는 복수개의 시퀀스들이 이진 시퀀스로 구성되어 있어 단말은 셀 ID를 추정하기 위해 복소 연산을 수행하지 않을 수 있다.According to an embodiment of the present invention,

The mobile station may not perform the complex operation to estimate the cell ID.

The methods according to the present invention can be implemented in the form of program instructions that can be executed through various computer means and recorded on a computer readable medium. The computer readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions recorded on the computer readable medium may be those specially designed and constructed for the present invention or may be available to those skilled in the computer software.

Examples of computer readable media include hardware devices that are specially configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those generated by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate with at least one software module to perform the operations of the present invention, and vice versa.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined in the appended claims. It will be possible.

Claims (1)

In a method of transmitting a synchronization signal performed by a base station,
Generating a base sequence;
Inverting a polarity of at least one of a real part and an imaginary part of the base sequence to generate a modified sequence; And
And transmitting the synchronization signal including the base sequence and the modified sequence through a frequency band,
Wherein the base sequence is mapped to one of a first frequency region having a frequency lower than a direct carrier (DC) subcarrier among the frequency bands or a second frequency region having a frequency higher than that of the DC subcarrier among the frequency bands, Wherein the deformation sequence is mapped to a frequency region to which the base sequence is not mapped in the first frequency region and the second frequency region.

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