KR102013846B1 - Method and appartus for generating synchronization signal in internet of things - Google Patents

Abstract

Disclosed are a method and apparatus for generating a synchronization signal in the IoT. Synchronization signal generation method, in the in-band operation mode or the guardband operation mode of the Internet of Things, of the total subcarriers allocated for the synchronization signal, the signals assigned to the upper subcarrier group and the signals assigned to the lower subcarrier group exchanged with each other, Subcarrier mapping may be performed.

Description

METHOD AND APPARTUS FOR GENERATING SYNCHRONIZATION SIGNAL IN INTERNET OF THINGS}

The present invention relates to a method and apparatus for generating a synchronization signal in the IoT.

Wireless communication systems for the IoT can serve a large area with low power and cost by using an orthogonal frequency division multiplexing (OFDM) transmission scheme. The wireless communication system supports various modes such as standalone operation mode, in-band operation mode, and guard band operation mode for versatility.

The standalone operation mode refers to a mode of operating a signal for providing an IoT service in a frequency band used by a global system for mobile communication (GSM). The in-band operation mode operates a signal for providing an IoT service in one or more of available resource blocks (hereinafter, referred to as 'RBs') in a frequency band used in an existing Long Term Evolution (LTE) system. Say the mode. In addition, the guardband operation mode is a signal for providing an IoT service in one or a plurality of unavailable (hereinafter referred to as 'unavailable') RBs in a frequency band used in a legacy Long Term Evolution (LTE) system. Refers to the mode of operating.

In-band operating mode and guardband operating mode may exist within the same frequency band. The available RBs or unusable RBs used for operation may be RBs physically located above (negative subcarriers with negative sign) from the center or RBs below (positive subcarriers with positive sign). To employ. That is, the in-band operation mode and the guardband operation mode do not employ the RB including the middle.

Although the wireless communication system of the IoT supports several operation modes as described above, signals related to synchronization need to be designed in the same way for general purpose. However, depending on whether the in-band / guardband operation mode or the standalone operation mode is used, the synchronization signal of the final time domain received by the receiver varies. Accordingly, the reception apparatus has a problem in that a memory for storing the final time-domain synchronization signal in the in-band / guardband operation mode and a memory for storing the final time-domain synchronization signal in the standalone operation mode must be separately located during synchronization estimation.

Meanwhile, the synchronization signal employed in the wireless communication system of the IoT may be generated by mapping a specific sequence to each of the frequency domain and the time domain (hereinafter, referred to as 'dual region sequence mapping'). In the standalone operation mode, since a signal can be mapped to a frequency band and a time domain independently of a frequency band to be used, there is no problem in generating a synchronization signal by dual region sequence mapping. However, since the in-band / guard-band operation mode uses one or some RBs depending on the frequency band used in the existing system, a problem may occur in generating a synchronization signal by dual region sequence mapping.

An object of the present invention is to provide a method and apparatus for generating a synchronization signal capable of performing synchronization estimation regardless of a mode.

Another object of the present invention is to provide a synchronization signal generation method and apparatus for enabling dual region sequence mapping even in an in-band / guardband operation mode.

According to an embodiment of the present invention, a method for generating a synchronization signal by a transmitting device in the IoT is provided. The method may include dividing an entire subcarrier allocated for the synchronization signal into a first upper subcarrier group and a first lower subcarrier group in an in-band operation mode or a guardband operation mode of the IoT. The method may include performing a first subcarrier mapping by exchanging a signal allocated to a subcarrier group and a signal allocated to the first lower subcarrier group.

The method may further include: dividing all subcarriers allocated for the synchronization signal into a second upper subcarrier group and a second lower subcarrier group in the standalone mode of the IoT, and the second upper subcarrier group and the second subcarrier group. The method may further include performing a second subcarrier mapping without exchanging lower subcarrier groups.

The method may further include performing subcarrier indexing on the first subcarrier mapped signal, performing an inverse fast fourthier transform (IFFT) on the subcarrier indexed signal, and performing CP (CP) on the IFFT performed signal. The method may further include inserting a Cyclic Prefix).

The method may further include performing subcarrier indexing on the second subcarrier mapped signal, performing an inverse fast fourthier transform (IFFT) on the subcarrier indexed signal, and performing CP (CP) on the IFFT performed signal. The method may further include inserting a Cyclic Prefix).

The first upper subcarrier group may be physically included in the negative subcarrier group, and the first lower subcarrier group may be physically included in the positive subcarrier group.

The second upper subcarrier group and the second lower subcarrier group may be physically included in the negative subcarrier group.

When the total number of subcarriers is 12, the indices of the first upper subcarrier group and the second upper subcarrier group are -1, 0, 1, 2, 3, and 4, respectively, and the first lower subcarrier group and the first subcarrier group are respectively. The indexes for the 2 lower subcarrier groups may be 5, 6, 7, 8, 9, and 10, respectively.

The method may further include determining whether the operation mode for the IoT is the standalone operation mode, the in-band operation mode, or the guardband operation mode.

According to another embodiment of the present invention, a method for generating a synchronization signal by a transmitting device in the IoT is provided. The method may include generating a Zadoff-Chu (ZC) sequence in an in-band operation mode or a guardband operation mode of the IoT, performing code covering on the ZC sequence,

Performing subcarrier mapping on the code covered signal, performing inverse fast fourier tranform (IFFT) on the subcarrier mapped signal, and inserting a cyclic prefix (CP) on the IFFT signal It may include a step.

The performing of the subcarrier mapping may include performing subcarrier mapping by exchanging a signal allocated to an upper subcarrier group and a signal allocated to a lower subcarrier group among all subcarriers allocated for the ZC sequence. have.

The upper subcarrier group may be physically included in the negative subcarrier group, and the lower subcarrier group may be physically included in the positive subcarrier group.

According to another embodiment of the present invention, there is provided a transmitting device for transmitting a synchronization signal in the IoT. The transmitter transmits a first subcarrier mapping by exchanging a first upper subcarrier group and a first lower subcarrier group among all subcarriers allocated for the synchronization signal in an in-band operation mode or a guardband operation mode of the IoT. By performing, may include a processor for generating the synchronization signal, and an RF module for transmitting the generated synchronization signal.

In the standalone mode of the IoT, the processor performs a second subcarrier mapping without exchanging a second upper subcarrier group and a second lower subcarrier group among all subcarriers allocated for the synchronization signal, and performs the synchronization. You can generate a signal.

The processor may perform subcarrier indexing on the first subcarrier mapped signal, perform inverse fast fourier transform (IFFT) on the subcarrier indexed signal, and perform cyclic prefix (CP) on the IFFT performed signal. You can insert

The first upper subcarrier group may be physically included in the negative subcarrier group, and the first lower subcarrier group may be physically included in the positive subcarrier group.

The second upper subcarrier group and the second lower subcarrier group may be physically included in the negative subcarrier group.

According to an embodiment of the present invention, the receiving device may use one memory regardless of the operation mode when estimating the synchronization signal.

According to another embodiment of the present invention, the transmission apparatus may map the dual region sequence even in the in-band / guard-band operation mode.

1 is a diagram illustrating a method of generating a synchronization signal in a standalone operation mode according to an exemplary embodiment of the present invention.
2 is a diagram illustrating a synchronization signal generation method in an in-band operation mode according to an embodiment of the present invention.
3 is a diagram illustrating a synchronization signal generation method in an in-band operation mode according to another embodiment of the present invention.
4 is a flowchart illustrating a method of generating a synchronization signal in a transmission apparatus according to an embodiment of the present invention.
5 is a diagram illustrating a transmission apparatus according to an embodiment of the present invention.
6 is a diagram illustrating a method of generating a time domain synchronization signal by dual domain sequence mapping in a standalone operation mode according to another embodiment of the present invention.
FIG. 7 is a diagram illustrating a method of generating a time domain synchronization signal by dual domain sequence mapping in an in band operation mode or a guard band operation mode according to another embodiment of the present invention.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, the receiving device is a terminal, a mobile terminal (MT), a mobile station (MS), an advanced mobile station (AMS), a high reliability mobile station (HR) -MS), subscriber station (SS), portable subscriber station (PSS), access terminal (AT), user equipment (UE), etc. It may include all or part of the functionality of the MT, AMS, HR-MS, SS, PSS, AT, UE, and the like.

In addition, the transmitting apparatus includes a base station (BS), an advanced base station (ABS), a high reliability base station (HR-BS), a node B (node B), and an advanced node B (evolved). node B, eNodeB), access point (AP), radio access station (RAS), base transceiver station (base transceiver station, BTS), MMR (mobile multihop relay) -BS, base station It may also refer to a relay station (RS), a high reliability relay station (HR-RS) that performs a role of a base station, and may also refer to a BS, ABS, Node B, eNodeB, AP, RAS, BTS, MMR-, and the like. It may also include all or part of the functions of the BS, RS, HR-RS and the like.

In the following description, for convenience of description, the number of subcarriers in the frequency domain allocated to the synchronization signal of the described IoT is set to 12 in total, but the number may be changed. In addition, the synchronization signal generating method described below may be performed by a transmitting apparatus.

)에 의해 생성된다. The synchronization signal according to the embodiment of the present invention is generated by Equation 1 below. The synchronization signal is a length-11 (length-11) ZC (Zadoff-Chu) sequence of a frequency domain as shown in Equation 1 below.

Is generated by

로 정의될 수 있다. In the equation (1), 5 indicates the root index of the ZC sequence, l refers to the OFDM symbol index. And, in Equation 1

It can be defined as.

1 is a diagram illustrating a method of generating a synchronization signal in a standalone operation mode according to an exemplary embodiment of the present invention. In more detail, the synchronization signal generation method of FIG. 1 illustrates a time domain synchronization signal generation method including frequency domain mapping when 128-point Inverse Fast Fourier Tranform (IFFT) is applied.

In FIG. 1, k denotes an index for each subcarrier, and n denotes a subcarrier index for a synchronization signal. Subcarriers with index k of 0 to 63 physically mean a negative subcarrier group, and subcarriers with index k of 64 to 127 physically mean a positive subcarrier group. 110 denotes a subcarrier allocated to a synchronization signal of the IoT, 120 denotes a DC subcarrier, and 130 denotes an unused subcarrier.

에 해당함) 인 위치(110, 120)에 상기 수학식 1의 동기 시퀀스를 할당하면, 전체 부반송파에 할당된 신호

를 얻을 수 있다. 본 발명의 실시예에서는 이와 같은 과정을 '부반송파 매핑(Subcarrier mapping)'이라 한다. The transmitting device has a subcarrier index n of -1 to 10

Corresponding to)) when the synchronization sequence of Equation 1 is allocated to positions 110 and 120, the signals allocated to all subcarriers

Can be obtained. In the embodiment of the present invention, such a process is referred to as 'subcarrier mapping'.

는 아래의 수학식 2와 같이 주파수영역에서 변경된다. 본 발명의 실시예에서는 이와 같은 과정을 '부반송파 인덱싱(Subcarrier indexing)'이라 한다. 즉, 도 1과 같이, 부반송파 매핑이 수행된 후 서로 교차하여 인덱싱이 수행되는데, 이를 부반송파 인덱싱이라 한다. Next, indexing is performed to match the subcarrier index in IFFT transform with the subcarrier index in physical meaning. Once indexing is performed,

Is changed in the frequency domain as shown in Equation 2 below. In the embodiment of the present invention, such a process is referred to as 'subcarrier indexing'. That is, as shown in FIG. 1, after subcarrier mapping is performed, indexing is performed by crossing each other. This is called subcarrier indexing.

When the transmitting apparatus performs a 128-point IFFT on the subcarrier indexed frequency domain signal and inserts a cyclic prefix (CP), a synchronization signal in the time domain is generated.

2 is a diagram illustrating a synchronization signal generation method in an in-band operation mode according to an embodiment of the present invention. In more detail, the synchronization generation method of FIG. 2 illustrates a time domain synchronization signal generation method including a frequency domain in a legacy LTE system having a 20 MHz bandwidth.

In FIG. 2, subcarriers with index k of 0 to 1023 physically mean negative subcarrier groups, and subcarriers with index k of 1024 to 2047 physically mean positive subcarrier groups. In addition, 210 denotes a subcarrier allocated to a synchronization signal of the IoT, and 220 denotes an existing LTE subcarrier.

를 얻을 수 있다. When the transmitting device allocates the synchronization sequence of Equation 1 to a position 210 in which the subcarrier index n is -1 to 10, the signal allocated to all subcarriers

Can be obtained.

는 아래의 수학식 3과 같이 주파수영역에서 변경된다. Next, subcarrier indexing is performed to match the subcarrier index in IFFT conversion with the subcarrier index in physical meaning. When subcarrier indexing is performed,

Is changed in the frequency domain as shown in Equation 3 below.

When the transmitter performs a 2048-point IFFT on the subcarrier indexed frequency domain signal as described above and inserts a cyclic prefix (CP), a synchronization signal in the time domain is generated.

Meanwhile, the reception apparatus of the IoT performs filtering on the time domain signal of the in-band operation mode generated as shown in FIG. 2, and performs filtering on the time domain signal of the standalone operation mode generated as shown in FIG. 1. However, since the time-domain signals filtered for each of the two modes are not correlated with each other, the receiving apparatus has a problem in that the time-domain synchronization signal must be stored in a separate memory for each mode. This causes an increase in memory cost and power consumption of the receiving device.

A method for solving this problem will be described with reference to FIG. 3 below.

3 is a diagram illustrating a synchronization signal generation method in an in-band operation mode according to another embodiment of the present invention. In more detail, the synchronization generation method of FIG. 3 illustrates a time domain synchronization signal generation method including a frequency domain in an LTE system having a 20 MHz bandwidth.

Since the synchronization signal method of FIG. 3 is the same as that of FIG. 2 except for the subcarrier mapping method, a redundant description is omitted. In FIG. 3, subcarriers with index k of 0 to 1023 physically mean negative subcarrier groups, and subcarriers with index k of 1024 to 2047 physically mean positive subcarriers. In addition, 310 represents a subcarrier allocated to a synchronization signal of the IoT, and 320 represents a legacy LTE subcarrier.

를 차례대로 할당하고, 도 2의 부반송파 인덱스 n이 5에서 10인 위치에 상기 수학식 1의

를 할당한다. 즉, n이 5에서 10까지의 부반송파가 먼저 할당되고 n이 -1에서 4까지의 부반송파가 할당된다. 다시 말하면, 수신 장치의 복잡도를 줄이기 위해, 송신 장치는 사물인터넷에 할당되는 전체 동기신호 부반송파들(310)에서, 상위 부반송파 그룹(

)에 할당된 신호와 하위 부반송파 그룹(

)에 할당된 신호를 서로 교환하여 부반송 매핑을 수행한다. As shown in FIG. 3, the transmitting apparatus of Equation 1 is located at a position where the subcarrier index n of FIG. 2 is -1 to 4.

Are sequentially assigned, and the subcarrier index n in FIG.

Allocate That is, subcarriers of n to 5 to 10 are allocated first, and subcarriers of n to 1 to 4 are allocated. In other words, in order to reduce the complexity of the receiving apparatus, the transmitting apparatus includes a higher subcarrier group in all synchronization signal subcarriers 310 allocated to the IoT.

Signal and lower subcarrier group (

Subcarrier mapping is performed by exchanging the signals assigned to each other).

)과 상위 부반송파 그룹((

)의 순서를 가진다. 즉, 도 1 및 도 3를 참조하면, 부반송파 인덱싱 한 후의 부반송파 순서가 스탠드얼론 동작 모드와 인밴드 동작 모드간에 서로 동일하다. The transmitting apparatus exchanges subcarriers in this way and performs subcarrier indexing. As shown in FIG. 3, the result of performing subcarrier indexing is determined by a lower subcarrier group (

) And the parent subcarrier group ((

Has the order That is, referring to FIGS. 1 and 3, the subcarrier order after subcarrier indexing is the same between the standalone operation mode and the inband operation mode.

Meanwhile, the reception apparatus of the IoT performs filtering on the time domain signal of the in-band operation mode generated as shown in FIG. 3, and performs filtering on the time domain signal of the standalone operation mode generated as shown in FIG. 1. However, since the time-domain signals filtered for each of the two modes are correlated with each other, the receiving apparatus may estimate the synchronization signal using one memory regardless of the modes. This can reduce the memory cost and power consumption of the receiving device.

2 and 3 have been described with respect to the synchronization generation method in the in-band operation mode, the descriptions described in Figures 2 and 3 can be equally applied to the guard band operation mode.

4 is a flowchart illustrating a method of generating a synchronization signal in a transmission apparatus according to an embodiment of the present invention.

First, the transmitter determines an operation mode supported by the wireless communication system of the IoT (S410). That is, the transmitter determines whether the operation mode is a standalone operation mode, an in-band operation mode, or a guardband operation. The method of determining the operation mode can be understood by those skilled in the art to which the present invention pertains, and thus a detailed description thereof will be omitted.

)에 할당된 신호와 하위 부반송파 그룹(

)에 할당된 신호를 서로 교환하지 않고, 부반송 매핑을 수행한다. In operation S410, when the operation mode is the standalone operation mode, the transmitting apparatus performs non-carrier subcarrier mapping (S420). That is, in the standalone operation mode, as described with reference to FIG. 1, the transmitting apparatus allocates a synchronization sequence of Equation 1 at positions 110 and 120 where n is from -1 to 10 to perform subcarrier mapping. In other words, in the standalone mode of operation, the transmitting device is a higher subcarrier group (

Signal and lower subcarrier group (

Subcarrier mapping is performed without exchanging the signals allocated to

The transmitting apparatus performs subcarrier indexing after performing non-carrier subcarrier mapping in step S420 (S430). That is, the transmitting apparatus performs subcarrier indexing by applying Equation 2, as described in FIG.

The transmitter performs an IFFT after the operation S430 and inserts a CP to generate time-domain synchronization signals for the standalone operation mode (S440 and S450).

)에 할당된 신호와 하위 부반송파 그룹(

)에 할당된 신호를 서로 교환하여, 부반송 매핑을 수행한다.Meanwhile, in operation S410, when the operation mode is the in-band operation mode or the guardband operation mode, the transmitting apparatus performs exchange subcarrier mapping. That is, in the in-band operation mode or the guardband operation mode, as described in FIG. 3, the transmitting apparatus allocates subcarriers of n to 5 to 10 first, and n sequentially assigns subcarriers of -1 to 4 in order. Assign. In other words, in the in-band operation mode / guardband operation mode, the transmitting apparatus may use the higher subcarrier group (

Signal and lower subcarrier group (

Sub-carrier mapping is performed by exchanging the signals assigned to each other).

The transmitting apparatus performs subcarrier indexing after performing the exchange subcarrier mapping in step S460 (S470). That is, the transmitter performs subcarrier indexing by applying Equation 2 above.

The transmitter performs an IFFT after the operation S460 and inserts a CP to generate time-domain synchronization signals for the in-band operation mode / guardband operation mode (S480 and S490).

5 is a diagram illustrating a transmission apparatus according to an embodiment of the present invention.

As shown in FIG. 5, a transmission device 500 according to an embodiment of the present invention includes a processor 510, a memory 520, and an RF module 530.

The processor 510 is designed to implement the synchronization signal generation method described with reference to FIGS. 1 to 4.

The memory 520 is connected to the processor 510 and stores various information related to the operation of the processor 510.

The RF module 530 is connected to an antenna (not shown) and transmits or receives a radio signal. The antenna may be implemented as a single antenna or multiple antennas (MIMO antenna).

Hereinafter, a method of solving the dual region sequence mapping problem in generating a synchronization signal will be described with reference to FIGS. 6 and 7.

6 is a diagram illustrating a method of generating a time domain synchronization signal by dual domain sequence mapping in a standalone operation mode according to another embodiment of the present invention. Each step of FIG. 6 may be performed by the processor of FIG. 5.

은 CP를 포함하는 하나의 OFDM 심볼 구간 동안 동일한

값을 유지하는 코드 커버링(code covering) 시퀀스를 의미한다. 코드 커버링 시퀀스는 본 발명이 속하는 기술 분야의 통상의 지식을 가진 자라면 알 수 있는 바 구체적인 설명은 생략한다. First, the transmitter generates a length-11 ZC sequence having a root index of 5 as shown in Equation 1 (S610). In operation S620, the transmitter performs subcarrier mapping and indexing described with reference to FIG. The transmitter performs IFFT and performs CP insertion (S630 and S640). The transmitting device performs code covering after performing step S640 to generate a time domain synchronization signal by dual region sequence mapping (S650). here,

Is the same during one OFDM symbol period including CP

A code covering sequence that maintains a value. The code covering sequence is known to those skilled in the art to which the present invention pertains, and thus a detailed description thereof will be omitted.

Meanwhile, in the in-band operation mode or the guard band operation mode, the independent frequency domain processing and time domain processing may not be performed as shown in FIG. 6, but are dependent on the frequency domain processing and the time domain processing of the existing LTE system. In order to perform code covering under such dependent conditions, a synchronization signal generation method as shown in FIG. 6 may be used.

FIG. 7 is a diagram illustrating a method of generating a time domain synchronization signal by dual domain sequence mapping in an in band operation mode or a guard band operation mode according to another embodiment of the present invention. Each step of FIG. 7 may be performed by the processor of FIG. 6.

First, the transmitting apparatus generates a length-11 ZC sequence having a root index of 5 as shown in Equation 1 and performs code covering on the ZC sequence (S710). A frequency domain synchronization sequence code-covered to a ZC sequence is shown in Equation 4 below.

이 곱해진 형태이다. As shown in Equation 4, the frequency domain synchronization sequence is a code covering sequence in the equation.

This is the multiplied form.

In operation S720, the transmitting apparatus performs subcarrier mapping (ie, exchange subcarrier mapping) and subcarrier indexing. The transmitter performs IFFT and performs CP insertion (S730, S740).

Meanwhile, even in the standalone operation mode, the same time domain synchronization signal may be generated by performing code covering in the frequency domain as shown in FIG. 7 instead of performing code covering in the time domain as shown in FIG. 6.

In addition, although the above-described embodiment of the present invention has been described with the synchronous signal as an example, it may be applied to a control signal or a data signal that is not a synchronous signal.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

Claims (16)

A method for generating a synchronization signal by a transmitting device in the Internet of Things,
In the in-band operation mode or guardband operation mode of the IoT,
Dividing all subcarriers allocated for the synchronization signal into a first upper subcarrier group and a first lower subcarrier group; and
Exchanging a signal allocated to the first upper subcarrier group and a signal allocated to the first lower subcarrier group, and performing a first subcarrier mapping;
In the standalone operation mode of the IoT,
Dividing all subcarriers allocated for the synchronization signal into a second upper subcarrier group and a second lower subcarrier group; and
And performing a second subcarrier mapping without exchanging the second upper subcarrier group and the second lower subcarrier group. delete The method of claim 1,
Performing subcarrier indexing on the first subcarrier mapped signal;
Performing an Inverse Fast Fourier Tranform (IFFT) on the subcarrier indexed signal, and
And inserting a cyclic prefix (CP) for the IFFT signal. The method of claim 1,
Performing subcarrier indexing on the second subcarrier mapped signal;
Performing an Inverse Fast Fourier Tranform (IFFT) on the subcarrier indexed signal, and
And inserting a cyclic prefix (CP) for the IFFT signal. The method of claim 1,
Wherein the first upper subcarrier group is physically included in a negative subcarrier group, and the first lower subcarrier group is physically included in a positive subcarrier group. The method of claim 1,
The second upper subcarrier group and the second lower subcarrier group are physically included in the negative subcarrier group. The method of claim 1,
If the total subcarriers total 12,
The indexes for the first upper subcarrier group and the second upper subcarrier group are -1, 0, 1, 2, 3, and 4, respectively, and the indices for the first lower subcarrier group and the second lower subcarrier group are respectively. 5, 6, 7, 8, 9, 10. The method of claim 1,
Determining whether the operation mode for the IoT is the standalone operation mode, the in-band operation mode, or the guardband operation mode. delete delete delete A transmitter for transmitting a synchronization signal in the Internet of Things,
In the in-band operation mode or the guardband operation mode of the IoT, by performing a first subcarrier mapping by exchanging a first upper subcarrier group and a first lower subcarrier group among all subcarriers allocated for the synchronization signal, A processor for generating a synchronization signal, and
An RF module for transmitting the generated synchronization signal,
In the standalone operation mode of the IoT, the processor performs a second subcarrier mapping without exchanging a second upper subcarrier group and a second lower subcarrier group among all subcarriers allocated for the synchronization signal. A transmitter for generating a synchronization signal. delete The method of claim 12,
The processor performs subcarrier indexing on the first subcarrier mapped signal, performs Inverse Fast Fourier Tranform (IFFT) on the subcarrier indexed signal, and cyclic prefix (CP) on the IFFT performed signal. Sending device for inserting. The method of claim 12,
The first upper subcarrier group is physically included in the negative subcarrier group, and the first lower subcarrier group is physically included in the positive subcarrier group. The method of claim 12,
The second upper subcarrier group and the second lower subcarrier group are physically included in a negative subcarrier group.

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