KR20100061291A - Apparatus and method for data transmission in wireless communication system - Google Patents

Abstract

Provided is a data transmission apparatus in a wireless communication system. The apparatus may include an OFDM symbol generator for generating a plurality of Orthogonal Frequency Division Multiplexing (OFDM) symbols, a frame configuration unit for configuring a frame including the plurality of OFDM symbols, and the plurality of frames based on the configured frames. It includes a transmitter for transmitting the OFDM symbol of. The frame is divided into a plurality of subframes, and the number of OFDM symbols included in any subframe is any one of 5, 6, and 7, and the system bandwidth of the wireless communication system is 8.75 MHz. The new frame configuration allows you to meet new parameter requirements while considering backward support.

Description

Apparatus and method for transmitting data in wireless communication system {APPARATUS AND METHOD FOR DATA TRANSMISSION IN WIRELESS COMMUNICATION SYSTEM}

The present invention relates to wireless communication, and more particularly, to an apparatus and method for transmitting data in a wireless communication system.

The Institute of Electrical and Electronics Engineers (IEEE) 802.16 standard provides technologies and protocols to support Broadband Wireless Access. Standardization has been in progress since 1999, and IEEE 802.16-2001 was approved in 2001. This is based on the Single Carrier physical layer called 'WirelessMAN-SC'. Later, in the IEEE 802.16a standard approved in 2003, 'WirelessMAN-OFDM' and 'WirelessMAN-OFDMA' were added to the physical layer in addition to 'WirelessMAN-SC'. After the completion of the IEEE 802.16a standard, the revised IEEE 802.16-2004 standard was approved in 2004. In order to correct bugs and errors in the IEEE 802.16-2004 standard, IEEE 802.16-2004 / Cor1 (hereinafter referred to as IEEE 802.16e) was completed in 2005 in the form of 'corrigendum'.

1 shows an example of a frame structure in an IEEE 802.16e system. A frame is a sequence of data for a fixed time used by physical specifications. This may be referred to section 8.4.4.2 of the IEEE standard 802.16-2004 "Part 16: Air Interface for Fixed Broadband Wireless Access Systems" (hereafter reference 1).

Referring to FIG. 1, a frame includes a downlink (DL) frame and an uplink (UL) frame. In Time Division Duplex (TDD), uplink and downlink transmissions share the same frequency but occur at different times. The downlink frame is temporally ahead of the uplink frame. The downlink frame starts with a preamble, a frame control header (FCH), a downlink (DL) -MAP, an uplink (MAP) -MAP, and a burst region. A guard time for distinguishing the uplink frame and the downlink frame is inserted in the middle part (between the downlink frame and the uplink frame) and the last part (after the uplink frame) of the frame. A transmit / receive transition gap (TGT) is a gap between a downlink burst and a subsequent uplink burst. A receive / transmit transition gap (RTG) is a gap between an uplink burst and a subsequent downlink burst. The preamble is used for initial synchronization, cell search, frequency offset, and channel estimation between the base station and the terminal. The FCH includes the length of the DL-MAP message and the coding scheme information of the DL-MAP. DL-MAP is an area where a DL-MAP message is transmitted. The DL-MAP message defines the connection of the downlink channel. The UL-MAP is an area in which the UL-MAP message is transmitted. The UL-MAP message defines the access of an uplink channel.

Currently, standardization of IEEE 802.16m, which is a new technical standard standard, is progressing based on IEEE 802.16e. In standardization of IEEE 802.16m, existing system parameters may be newly defined. Accordingly, there is a need to configure a frame structure to efficiently support newly defined system parameters.

In addition, IEEE 802.16m, a newly developed technical standard, should be designed to support IEEE 802.16e designed earlier. The technology of the newly designed system should be configured to efficiently cover the existing technology (IEEE 802.16e). This is called backward compatibility. A frame that satisfies backward support for an existing system is called a dual frame. The existing system may mean an IEEE 802.16e system, and the new system may mean IEEE 802.16m. Therefore, studies on the structure of a frame that can satisfy the back support for the IEEE 802.16e system in the IEEE 802.16m system.

Furthermore, although the system profile based on the conventional IEEE 802.16 standard supports only the TDD (Time Division Duplexing) scheme, the system profile is also intended to support the FDD (Fequency Division Duplexing) scheme in which uplink transmission and downlink transmission are simultaneously performed in different frequency bands. There is an attempt. Therefore, it is necessary to design an FDD frame structure having commonality with the TDD frame structure in order to facilitate system design and share hardware.

An object of the present invention is to provide an apparatus and method for transmitting data in a wireless communication system.

Provided is a data transmission apparatus in a wireless communication system. The apparatus may include an OFDM symbol generator for generating a plurality of Orthogonal Frequency Division Multiplexing (OFDM) symbols, a frame configuration unit for configuring a frame including the plurality of OFDM symbols, and the plurality of frames based on the configured frames. It includes a transmitter for transmitting the OFDM symbol of. The frame is divided into a plurality of subframes, and the number of OFDM symbols included in any subframe is any one of 5, 6, and 7, and the system bandwidth of the wireless communication system is 8.75 MHz.

Provided is a data transmission method in a wireless communication system. The method includes generating a plurality of OFDM symbols, constructing a frame comprising the plurality of OFDM symbols, and transmitting the plurality of OFDM symbols based on the configured frames. The frame is divided into a plurality of subframes, and the number of OFDM symbols included in any subframe is any one of 5, 6, and 7, and the system bandwidth of the wireless communication system is 8.75 MHz.

With the new frame configuration, new parameter requirements can be met while considering backward support.

2 is a block diagram illustrating a wireless communication system. Wireless communication systems are widely deployed to provide various communication services such as voice and packet data.

Referring to FIG. 2, the wireless communication system includes a user equipment (UE) 10 and a base station 20 (BS). The terminal 10 may be fixed or mobile and may be referred to by other terms such as a mobile station (MS), a user terminal (UT), a subscriber station (SS), and a wireless device. The base station 20 generally refers to a fixed station for communicating with the terminal 10 and may be referred to in other terms such as a NodeB, a base transceiver system (BTS), and an access point. . One or more cells may exist in one base station 20.

Hereinafter, downlink means communication from the base station 20 to the terminal 10, and uplink means communication from the terminal 10 to the base station 20. In downlink, the transmitter may be part of the base station 20 and the receiver may be part of the terminal 10. In uplink, the transmitter may be part of the terminal 10 and the receiver may be part of the base station 20.

A radio resource used for downlink transmission and a radio resource such as frequency, time, and code region used for uplink transmission are required to be distinguished from each other. This method is called duplex. As in the multiple access scheme for distinguishing different users, uplink and downlink can be distinguished in the frequency, time, and code domains. The duplex method is largely divided into a frequency division duplexing (FDD) method for dividing uplink and downlink into frequency and a time division duplexing (TDD) method for dividing uplink and downlink into time.

In the FDD scheme, since uplink and downlink are distinguished in the frequency domain, data transmission between the base station and the terminal may be continuously performed in the time domain on each link. The FDD scheme symmetrically allocates frequencies of the same size to the uplink and the downlink, and has been frequently used for symmetric services such as voice calls. On the other hand, there is a H-FDD (Half-FDD) scheme, which is a kind of FDD scheme. In the H-FDD scheme, the UE may not simultaneously perform uplink transmission and downlink transmission on different frequency bands. Therefore, in the H-FDD system, when terminals belonging to one group perform uplink transmission, the base station performs downlink transmission for terminals belonging to another group. That is, the uplink and the downlink are frequency-divided, and each group divides time from each other.

Since the TDD scheme can allocate different time slots for uplink and downlink, the TDD scheme is suitable for asymmetric services. Another advantage of the TDD scheme is that uplink and downlink are transmitted and received in the same frequency band, and thus the channel state of the uplink and downlink is almost identical. Therefore, the channel state can be estimated immediately upon receiving the signal, which is suitable for array antenna technology. The TDD method uses the entire frequency band as uplink or downlink, but since the uplink and downlink are distinguished in the time domain, it is used as an uplink for a predetermined time and as a downlink for another predetermined time. Data transmission and reception between the base station and the terminal can not be made at the same time.

The wireless communication system may be an orthogonal frequency division multiplexing (OFDM) / orthogonal frequency division multiple access (OFDMA) based system. OFDM uses multiple orthogonal subcarriers. OFDM utilizes orthogonality between Inverse Fast Fourier Transform (IFFT) and Fast Fourier Transform (FFT). The transmitter generates an OFDM symbol by performing IFFT on the data and transmits the OFDM symbol. The receiver performs FFT on the received OFDM symbol to recover the original data. The transmitter uses an IFFT to combine multiple subcarriers, and the receiver uses a corresponding FFT to separate multiple subcarriers.

Multiple access schemes for downlink and uplink transmission may be different. For example, downlink may use Orthogonal Frequency Division Multiple Access (OFDMA) and uplink may use Single Carrier-Frequency Division Multiple Access (SC-FDMA).

3 shows an example of an OFDM symbol structure.

Referring to FIG. 3, the total time length of one OFDM symbol is T _s = T _g + T _b . Here, T _g is a cyclic prefix (CP), and T _b is a useful symbol time. CP is used to remove inter-symbol interference due to multiple paths in the OFDM transmission scheme, and may be referred to as a guard interval or a guard time. T _b is the remainder of T _s except for CP and is an OFDM symbol part required to recover actual data.

If the ratio between T _g and T _b is G, the following equation holds.

T _g = GT _b

Here, G = 1/8 or 1/16. CP when G is 1/16 is called a normal CP, and when G is 1/8, a CP is called an extended CP.

The table below shows an example of parameters for an OFDM system. This is a system parameter in the IEEE 802.16m standard.

Referring to Table 1, it can be seen that each parameter is independently set according to the system transmission bandwidth. In particular, in a system with a system transmission bandwidth of 8.75 MHz, if G = 1/8, the number of OFDM symbols included in every 5 ms frame is 43. There is a need for a method of constructing a frame in which the system can operate efficiently based on these new parameters.

4 is a superframe structure according to an embodiment of the present invention.

Referring to FIG. 4, a superframe includes a superframe header (SFH) and four frames (frames, F0, F1, F2, and F3). In the case of using a superframe, the transmission period of control information that does not need to be transmitted frequently can be increased in units of superframes, thereby increasing the efficiency of transmission. In addition, data allocation and scheduling may be performed most frequently in units of superframes, thereby reducing delay characteristics of data transmission considering a retransmission mechanism. The size of each superframe is 20ms and the size of each frame is illustrated as 5ms, but is not limited thereto. Frames may be considered as variable sizes for compatibility with heterogeneous or legacy wireless communication systems.

The superframe header may be placed at the front of the superframe, and a common control channel is assigned. The common control channel is a channel used for transmitting control information that can be commonly used by all terminals in a cell, such as information on frames constituting a superframe or system information. A sync signal or preamble is located in the superframe header. The preamble is used for initial synchronization, cell search, frequency offset, and channel estimation between the base station and the terminal.

One frame includes k subframes (Subframe, SF0, SF1, SF2, ..., SF (k-1)). An integer with k> 0. 4 is a case where k is 7. The subframe may consist of 5, 6 or 7 OFDM symbols. Time division duplexing (TDD) or frequency division duplexing (FDD) may be applied to the frame. In TDD, each subframe is used in uplink or downlink at different times at the same frequency. That is, subframes in the TDD frame are divided into an uplink subframe and a downlink subframe in the time domain.

In FDD, each subframe is used as uplink or downlink on a different frequency at the same time. That is, subframes in the FDD frame are divided into uplink and downlink in the frequency domain. In this case, the uplink transmission and the downlink transmission occupy different frequency bands and may be simultaneously performed. The midamble is a signal for channel estimation transmitted by a base station to obtain a channel state for each antenna in a multiple-input multiple-output (MIMO) system using a plurality of antennas. The terminal may estimate the channel state for each antenna of the base station by receiving the midamble.

As described above, in a system having a system transmission frequency band of 8.75 MHz, if G = 1/8, the number of OFDM symbols included in one frame is 43. When a base station and a terminal exchange a frame, a minimum size of a transmission time interval (TTI), which is a basic unit of data transmission and reception, is a subframe. In such a system, in order to meet the new parameter requirements while considering backward support, the types of pilots, resource blocks, and structures of the physical layer are the same by making all subframe types as identical as possible. You need to construct a sustainable frame.

5 shows a data transmission apparatus in a wireless communication system according to an embodiment of the present invention.

Referring to FIG. 5, the data transmission apparatus 100 may include an OFDM symbol generating unit 110, a frame configuring unit 120, and a transmitting unit 130.

The OFDM symbol generator 110 generates a plurality of OFDM symbols by performing a fast fourier transform (FFT) and an inverse FFT (IFFT) on the input data symbols. The structure of the OFDM symbol is as described in FIG.

The frame configuration unit 120 configures a frame including the plurality of OFDM symbols. The general configuration of the frame is as described in FIG. The frame is divided into a plurality of subframes, and any subframe includes 5, 6 or 7 OFDM symbols. Of course, all subframes may include the same number of OFDM symbols or may include different numbers of OFDM symbols. However, the number of OFDM symbols included in one frame should be kept constant to 43. The frame may be a frame of the TDD scheme, the FDD scheme, or the H-FDD scheme.

In a frame of the TDD scheme, a transition between an uplink subframe and a downlink subframe may occur. A transition gap is inserted to smoothly perform a transition from an uplink subframe to a downlink subframe or a transition from a downlink subframe to an uplink subframe. The frame configuration unit 120 may transmit / receive at least one OFDM symbol to transmit / receive a transmission / reception gap (TX / RX transition gap; TTG) or a transmission / reception transition interval (RX / TX transition gap) that distinguishes an adjacent uplink subframe and a downlink subframe. RTG). This transition interval is also called idle gap.

A frame of the FDD scheme or the H-FDD scheme does not require a transition interval unlike a frame of the TDD scheme. Accordingly, the frame configuration unit 120 may allocate one OFDM symbol to a subframe or use it for another purpose. An OFDM symbol used for another purpose is called a redundant OFDM symbol. The redundant OFDM symbol may be used as a preamble, a synchronization channel, a midamble, or a sounding signal.

The transmitter 130 transmits the plurality of OFDM symbols based on the frame constituted by the frame constructor 120.

6 is an example of a frame structure of the TDD scheme configured by the frame configuration unit according to the present invention.

Referring to FIG. 6, the system transmission bandwidth is 8.75 MHz and G = 1/8. Therefore, the number of OFDM symbols available in one frame is 43. Frame structure types A-1 to A-5 are cases in which a frame is constructed using 42 OFDM symbols except one OFDM symbol used as a transmission / reception transition interval or a transmission transition interval. The number in parentheses of each subframe indicates the number of OFDM symbols included in the subframe. In order to make the number of OFDM symbols included in the subframe the same, seven subframes in one frame are configured. Based on this, each subframe includes six OFDM symbols.

Therefore, the number of OFDM symbols included in one frame is 7 (number of subframes) x 6 (number of OFDM symbols / subframes) + 1 (transition interval) = 43. According to such a frame configuration, this configuration can support the basic frame structure (subframe including six OFDM symbols) of IEEE 802.16m. In addition, all subframes have the same type including the same number of OFDM symbols.

The transmission and reception transition interval is located between adjacent downlink subframes and uplink subframes. That is, subframes before the transmission / reception transition interval (TTG) are downlink subframes, and subframes after the transmission / reception transition interval (TTG) are uplink subframes. Accordingly, frame structure types A-1, A-2, A-3, A-4, and A-5 have ratios of downlink subframes and uplink subframes of 2: 5, 3: 4, 4: 3, 5: 2, 6: 1. The transmission and reception transition interval (TTG) is 87.2 us, and the transmission and reception transition interval (RTG) is 74.4 us.

7 is another example of a frame structure of the TDD scheme configured by the frame configuration unit according to the present invention.

Referring to FIG. 7, the system transmission bandwidth is 8.75 MHz and G = 1/8. Therefore, the number of OFDM symbols available in one frame is 43. Frame structure type B-1 to B-5 is a case of configuring a frame using 42 remaining OFDM symbols except one OFDM symbol used as a transmission / reception transition interval or a transmission transition interval. In order to equalize the number of OFDM symbols included in the subframe, six subframes in one frame are configured. Based on this, each subframe includes seven OFDM symbols. Therefore, the number of OFDM symbols included in one frame is 6 (number of subframes) x 7 (number of OFDM symbols / subframes) + 1 (transition interval) = 43. This is the same as a type-2 subframe in IEEE 802.16m.

Since the number of subframes in one frame is an even number, symmetrical allocation of the downlink subframe and the uplink subframe is possible. Symmetrical assignment may facilitate the performance of the HARQ process. Frame structure types B-1, B-2, B-3, and B-4 have ratios of downlink subframes and uplink subframes of 2: 4, 3: 3, 4: 2, and 5: 1, respectively.

8 is another example of a frame structure of the TDD scheme configured by the frame configuration unit according to the present invention.

Referring to FIG. 8, the system transmission bandwidth is 8.75 MHz and G = 1/8. Therefore, the number of OFDM symbols available in one frame is 43. Frame structure type C-1 to C-5 is a case of constructing a frame using 42 remaining OFDM symbols except one OFDM symbol used as a transmission / reception transition interval or a transmission transition interval. It configures 8 subframes in one frame. Based on this, each subframe includes five or six OFDM symbols. That is, six subframes include five OFDM symbols, and the other two subframes include six OFDM symbols. Frame structure types C-1, C-2, C-3, C-4, C-5, and C-6 have ratios of downlink subframes and uplink subframes 3: 5, 4: 4, 5: 3, 6: 2. 5: 3.

In frame structure types C-1 to C-5, two subframes containing six OFDM symbols are located at both ends of the frame, respectively. On the other hand, in the frame structure type C-6, two subframes including six OFDM symbols are located at the front of the frame. This is a method in which uplink can support the frame configuration of IEEE 802.16e, which is 15 OFDM symbols. In the frame structure type C-6, the position of the transmission and reception transition interval (TTG) is between the fifth subframe and the sixth subframe, but this is only an example and may be located between other subframes.

By dividing one frame into eight subframes as described above, the number of subframes per frame considered in the system bands of 5, 10, and 20 MHz of IEEE 802.16m can be unified. In addition, control information in subframe units such as a HARQ protocol or a downlink-to-uplink ratio designed to support a 5, 10, 20 MHz system band can be made in the same form. Since the number of subframes is even, symmetrical allocation of the downlink subframe and the uplink subframe is possible. Symmetrical assignment may facilitate the performance of the HARQ process.

9 is an example of a frame structure of an FDD scheme configured by a frame configuration unit according to the present invention.

Referring to FIG. 9, the system transmission bandwidth is 8.75 MHz and G = 1/8. Therefore, the number of OFDM symbols available in one frame is 43. A frame of the FDD scheme or the H-FDD scheme does not require a transition interval unlike a frame of the TDD scheme. Accordingly, the frame configuration unit 120 may allocate all 43 OFDM symbols to a subframe or use at least one OFDM symbol for other purposes. The at least one OFDM symbol used for another purpose is called a redundant OFDM symbol.

Frame structure types D-1 through D-5 include all seven subframes. Only one specific subframe includes 7 OFDM symbols, and the remaining subframes include 6 OFDM symbols. In the particular subframe, considering the H-FDD frame structure considering the H-FDD UE, and considering the case where the group of UEs is divided into two, an additional idle symbol is likely to occur in the middle of the frame. . Therefore, the position of the specific subframe is preferably third, fourth, fifth.

Frame structure types D-2 through D-5 include all six subframes equally six OFDM symbols. Thus, one surplus OFDM symbol may be used for other purposes depending on the system. Frame structure type D-2 is a configuration in which redundant OFDM symbols are placed at the front of the frame. This is because the control information of a symbol unit such as a preamble or an FCH is mainly located in the front part of the frame, so that the redundant OFDM symbol is used as the control information and maintains the form of a subframe composed of 6 OFDM symbols for data transmission.

Frame structure types D-3 and D-4 are configurations that consider H-FDD frames or midambles. Accordingly, redundant OFDM symbols are placed between the third and fourth subframes or between the fourth and fifth subframes.

Frame structure type D-5 is a configuration in which sounding signals are considered. Thus, redundant OFDM symbols are placed at the end of the frame. Thus, additional control information can be transmitted without harming the configuration of the type-1 subframe of IEEE 802.16m.

10 is another example of the frame structure of the FDD scheme configured by the frame configuration unit according to the present invention.

Referring to FIG. 10, the system transmission bandwidth is 8.75 MHz and G = 1/8. Therefore, the number of OFDM symbols available in one frame is 43. It configures six subframes in one frame. Based on this, each subframe includes seven OFDM symbols. The remaining one excess OFDM symbol is not included in the subframe. This means that if a redundant OFDM symbol is included in a subframe, one subframe includes eight OFDM symbols, which undermines the basic frame configuration in IEEE 802.16m. Therefore, the redundant OFDM symbol is used only for other purposes.

Frame structure type D-1 is a configuration in which redundant OFDM symbols are placed in the center of a frame. The redundant OFDM symbol can be utilized for H-FDD or midamble.

Frame structure type D-2 is a configuration in which redundant OFDM symbols are placed at the front of the frame, and the redundant OFDM symbols are used for essential control information such as a preamble or an FCH.

Frame structure type D-3 is a configuration in which sounding signals are considered. Thus, redundant OFDM symbols are placed at the end of the frame. Thus, additional control information can be transmitted without harming the configuration of the type-1 subframe of IEEE 802.16m.

11 is another example of a frame structure of the FDD scheme configured by the frame configuration unit according to the present invention.

Referring to FIG. 11, the system transmission bandwidth is 8.75 MHz and G = 1/8. Therefore, the number of OFDM symbols available in one frame is 43. It configures 8 subframes in one frame. Each subframe includes five or six OFDM symbols. The basic configuration uses a long subframe (i.e., six OFDM symbols) at the front and the end of the frame in order to unify the TDD frame structure and G = 1/16 in the system bandwidths of 5, 10, and 20 MHz. Subframes).

The method of configuring eight subframes is as follows. As an example, five subframes include five OFDM symbols, and the remaining three subframes include six OFDM symbols. Frame structure types F-1 and F-2 are the constructions by this method. One of three subframes including six OFDM symbols is preferably disposed in the middle, that is, the fourth or fifth subframe in consideration of the H-FDD scheme. However, in the present patent this is only an example, and there is no limitation on any other located FDD structure.

As another example, six subframes include five OFDM symbols, the remaining two subframes include six OFDM symbols, and one redundant OFDM symbol. Frame structure types F-3 to F-5 are the constructions by this method. A redundant OFDM symbol may be considered to be arranged independently. The redundant OFDM symbol is used for essential control information such as an H-FDD scheme or a preamble.

The invention can be implemented in hardware, software or a combination thereof. (DSP), a programmable logic device (PLD), a field programmable gate array (FPGA), a processor, a controller, a microprocessor, and the like, which are designed to perform the above- , Other electronic units, or a combination thereof. In the software implementation, the module may be implemented as a module that performs the above-described function. The software may be stored in a memory unit and executed by a processor. The memory unit or processor may employ various means well known to those skilled in the art.

As mentioned above, preferred embodiments of the present invention have been described in detail, but those skilled in the art to which the present invention pertains should understand the present invention without departing from the spirit and scope of the present invention as defined in the appended claims. It will be appreciated that various modifications or changes can be made. Accordingly, modifications of the embodiments of the present invention will not depart from the scope of the present invention.

1 shows an example of a frame structure in an IEEE 802.16e system.

2 is a block diagram illustrating a wireless communication system.

3 shows an example of an OFDM symbol structure.

4 is a superframe structure according to an embodiment of the present invention.

5 shows a data transmission apparatus in a wireless communication system according to an embodiment of the present invention.

6 is an example of a frame structure of the TDD scheme configured by the frame configuration unit according to the present invention.

7 is another example of a frame structure of the TDD scheme configured by the frame configuration unit according to the present invention.

8 is another example of a frame structure of the TDD scheme configured by the frame configuration unit according to the present invention.

9 is an example of a frame structure of an FDD scheme configured by a frame configuration unit according to the present invention.

10 is another example of the frame structure of the FDD scheme configured by the frame configuration unit according to the present invention.

11 is another example of a frame structure of the FDD scheme configured by the frame configuration unit according to the present invention.

Claims (14)

In a data transmission apparatus in a wireless communication system, An OFDM symbol generator configured to generate a plurality of Orthogonal Frequency Division Multiplexing (OFDM) symbols; A frame configuration unit constituting a frame including the plurality of OFDM symbols; And A transmitter for transmitting the plurality of OFDM symbols based on the configured frame, The frame is divided into a plurality of subframes, and the number of OFDM symbols included in any of these subframes is any one of 5, 6, and 7, and the system bandwidth of the wireless communication system is 8.75 MHz, Data transmission device. The method of claim 1, The time length of each OFDM symbol is equal to the sum of a cyclic prefix (CP) and a useful symbol time, and the ratio of the CP and the useful time is 1: 8. The method of claim 1, And the number of the plurality of OFDM symbols is 43. The method of claim 1, The random subframe is any one of a downlink subframe used for downlink transmission and an uplink subframe used for uplink transmission. The method of claim 4, wherein At least one OFDM symbol in the frame is used as a transmission / reception gap (TX / RX gap) for distinguishing adjacent downlink subframes and uplink subframes. The method of claim 1, Within the arbitrary subframe, a frequency band for downlink transmission and a frequency band for uplink transmission are divided and allocated. The method of claim 1, At least one OFDM symbol in the frame is used as a preamble or a midamble. The method of claim 1, And six OFDM symbols included in each of the plurality of subframes are the same. In the data transmission method in a wireless communication system, Generating a plurality of OFDM symbols; Constructing a frame including the plurality of OFDM symbols; And Transmitting the plurality of OFDM symbols based on the configured frame, The frame is divided into a plurality of subframes, and the number of OFDM symbols included in any of these subframes is any one of 5, 6, and 7, and the system bandwidth of the wireless communication system is 8.75 MHz, Data transfer method. The method of claim 9, The time length of each OFDM symbol is equal to the sum of CP and effective symbol time, and the ratio of the CP and the effective symbol time is 1: 8. The method of claim 9, The number of the plurality of OFDM symbols is 43, the data transmission method. The method of claim 9, The wireless communication system is a time division duplex (TDD) system in which uplink transmission and downlink transmission are divided into subframe units. 13. The method of claim 12, Within the frame, the ratio of the downlink subframe used for the downlink transmission and the uplink subframe used for the uplink transmission is N: M, and N + M is any one of 6, 7, and 8, data transmission. Way. The method of claim 13, At least one OFDM symbol in the frame is used as a transport spreading interval (RX / TX gap) to distinguish the adjacent uplink subframe and the downlink subframe.

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