KR20090062737A - Method for mapping radio resource in sc-fdma system and transmitter using the same - Google Patents

Abstract

A radio resource mapping method and a transmitter using the same are provided to arrange data in a resource area as maintaining the high reliability. A resource allocation mapper(110) assigns data symbols to a time-frequency resource area. A DFT(Discrete Fourier Transform unit)(120) performs the DFT for the inputted data symbols to output frequency-region symbols. A frequency region mapper(130) assigns the input signals to each subcarrier. An IFFT(Inverse Fast Fourier Transform) unit(140) performs the IFFT to output a transmission signal. A radio frequency unit(150) converts the inputted symbols into analog signals.

Description

Method for mapping radio resource in SC-FDMA system and transmitter using the same}

The present invention relates to wireless communication, and more particularly, to a method for efficiently mapping multiple types of data having different importance to a resource region and a transmitter using the same.

3rd generation partnership project (3GPP) mobile communication systems based on wideband code division multiple access (WCDMA) wireless access technology are widely deployed around the world. High Speed Downlink Packet Access (HSDPA), which can be defined as the first evolution of WCDMA, provides 3GPP with a highly competitive wireless access technology in the mid-term future. However, as the demands and expectations of users and operators continue to increase, and the development of competing wireless access technologies continues to progress, new technological evolution in 3GPP is required to be competitive in the future.

One of the systems considered in 3rd generation and later systems is an Orthogonal Frequency Division Multiplexing (OFDM) system that can attenuate the effect of inter-symbol interference with low complexity. OFDM converts serially input data symbols into N parallel data symbols and transmits the data symbols on N subcarriers. The subcarriers maintain orthogonality in the frequency dimension. Each orthogonal channel experiences mutually independent frequency selective fading, and the interval between transmitted symbols is increased, thereby minimizing intersymbol interference. Orthogonal Frequency Division Multiple Access (OFDMA) refers to a multiple access method for realizing multiple access by independently providing each user with a part of subcarriers available in a system using OFDM as a modulation scheme. OFDMA provides each user with a frequency resource called a subcarrier, and each frequency resource is provided to a plurality of users independently so that they do not overlap each other. Eventually, frequency resources are allocated to each other exclusively.

One of the main problems with OFDM / OFDMA systems is that the Peak-to-Average Power Ratio (PAPR) can be very large. The PAPR problem is caused by the fact that the peak amplitude of the transmitted signal is much larger than the average amplitude, due to the fact that the OFDM symbol is a superposition of N sinusoidal signals on different subcarriers. PAPR is a problem especially in terminals that are sensitive to power consumption in relation to battery capacity. To reduce power consumption, it is necessary to lower the PAPR.

One system proposed to lower PAPR is Single Carrier-Frequency Division Multiple Access (SC-FDMA). SC-FDMA combines Frequency Division Multiple Access (FDMA) with Single Carrier-Frequency Division Equalization (SC-FDE). SC-FDMA has similar characteristics to OFDMA in that it modulates and demodulates data in time and frequency domain using Discrete Fourier Transform (DFT), but the PAPR of the transmission signal is low, which is advantageous in reducing transmission power. . In particular, it can be said that it is advantageous for the uplink to communicate with the base station from the terminal sensitive to the transmission power in relation to the use of the battery.

The data includes user data and control information related to the user data. The terminal may transmit only control information, or may multiplex user data and control information and transmit the same. If the control information is not transmitted, the base station or the terminal may not know whether the associated user data is transmitted. Therefore, the transmission of the control information requires high reliability.

In the case of transmitting control information requiring high reliability by multiplexing with user data, a method of arranging user data and control information in a resource area while maintaining reliability of the control information is not clearly presented.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a method for efficiently mapping multiple types of data having different importance to a resource region and a transmitter using the same.

According to an aspect of the present invention, a method for mapping data to a radio resource in a wireless communication system includes: mapping first data in consecutive OFDM symbols on a subframe including a plurality of OFDM symbols and a plurality of subcarriers, the subframe Mapping the second data in a line on the frequency axis on the first OFDM symbol selected from the above; and mapping the second data in a line on the frequency axis on the second OFDM symbol spaced apart from the first OFDM symbol. .

According to another aspect of the present invention, a transmitter is a resource allocation mapper for mapping first data to consecutive OFDM symbols on a subframe including a plurality of OFDM symbols, and mapping second data to OFDM symbols spaced apart from each other, wherein the first A DFT unit performing a DFT on the basis of OFDM symbols as a unit of data and the radio resource to which the second data is mapped; a frequency for allocating data symbols for the first data and the second data to subcarriers after performing the DFT And an area mapper and an IFFT unit configured to perform IFFT on the subcarriers to which the first data or the second data are allocated.

It can be arranged in the resource area so that the reliability of data requiring high reliability can be maintained, and different types of data can be effectively transmitted through limited radio resources.

1 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. 1, a 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 called 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 that communicates with the terminal 10, and in other terms, such as a Node-B, a Base Transceiver System, or an Access Point. Can be called. 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.

2 is a block diagram illustrating an example of a transmitter using SC-FDMA.

Referring to FIG. 2, the transmitter 100 includes a resource allocation mapper 110, a DFT unit 120 performing a discrete fourier transform (DFT), a frequency region mapper 130, and an IFFT ( An IFFT unit 140, an RF unit 150, and a transmission antenna 160 that perform an inverse fast fourier transform are included.

The resource allocation mapper 110 allocates data symbols to the time-frequency resource region. The data symbol may be an information stream for user data (first data) A = [a ₀ , a ₁ , ..., a_N _A -1] and / or an information stream for control information (second data) B = [b ₀ , b ₁ , ..., b_N _B -1]. The resource allocation mapper 110 maps data symbols included in one information stream to contiguous OFDM symbols and data symbols included in another information stream to OFDM symbols spaced apart from each other. You can map by different mapping locations in.

The DFT unit 120 performs a DFT on the input data symbol and outputs a frequency domain symbol. The data symbol input to the DFT unit 120 may be user data and / or control information. The DFT unit 120 performs a DFT in units of OFDM symbols to which user data and / or control information is mapped. The frequency domain mapper 130 allocates an input signal to each subcarrier according to various signal structure schemes. The frequency domain mapper 130 maps a reference signal to the resource domain. The IFFT unit 140 outputs a Tx signal by performing an IFFT on the input symbol. The transmission signal becomes a time domain signal. A time domain symbol output through the IFFT unit 140 is called an orthogonal frequency division multiplexing (OFDM) symbol. Alternatively, the OFDM symbol is also referred to as a single carrier-frequency division multiple access (SC-FDMA) symbol because the OFDM symbol is generated by performing a DFT at the front end of the IFFT unit 140 and then performing an IFFT. The DFT unit 120, the frequency domain mapper 130, and the IFFT unit 140 are called SC-FDMA processing units that process SC-FDMA symbols.

The RF unit 150 converts an input symbol into an analog signal. The converted analog signal is propagated to a wireless channel through the transmission antenna 160.

Modulation by combining DFT and IFFT is called SC-FDMA, which is advantageous to lower the Peak-to-Average Power Ratio (PAPR) compared to OFDM using only IFFT. This is because it has the characteristics of a single carrier.

3 shows an example of a subframe.

Referring to FIG. 3, a subframe may be divided into a control region and a data region. Control information is carried in the control area, and user data is loaded in the data area. The control area and the data area may consist of one subframe. There may be various kinds of control information such as an ACK / NAK signal, a channel quality indicator (CQI), a scheduling request signal, and MIMO control information. Only control information can be carried in the control area. In the data area, user data and control information can be loaded together. That is, when the terminal transmits only the control information, the control information may be transmitted through the control area. When the terminal transmits the user data and the control information, the control information may be transmitted through the control area or multiplexed between the user data and the control information. Can be transmitted through the data area. There is a PUCCH (Physical Uplink Control Channel) as a channel for transmitting control information through a control region in uplink. There is a PUSCH (Physical Uplink Shared Channel) as a channel for transmitting user data and control information through a data region in uplink.

The subframe may include two slots. A slot may be a unit for allocating radio resources in a time domain and a frequency domain. One slot may include a plurality of OFDM symbols in the time domain and at least one subcarrier in the frequency domain. For example, one slot may include 7 or 6 OFDM symbols. The subframe may include a plurality of resource blocks (RBs). Resource block is a basic unit of radio resources allocated to the terminal. The RB may include a plurality of subcarriers. For example, a resource block may be a region consisting of 12 consecutive subcarriers in the frequency domain and two slots in the time domain. Ten subframes may constitute one radio frame. The time taken to transmit one subframe is called a Transmission Time Interval (TTI). For example, when the TTI is 1ms, the slot is 0.5ms and the time required to transmit one radio frame is 10ms.

Here, the subframe divides the frequency band into three parts, with two parts on both sides as the control area, and an intermediate part as the data area. Since the control region and the data region use different frequency bands, the frequency division multiplexing (FDM) is performed. This is merely an example, and arrangement of the control region and the data region on the subframe is not limited. In addition, the number of subframes included in the radio frame or the number of slots included in the subframe and the number of OFDM symbols included in the slot may be variously changed.

Slots allocated to each terminal may be frequency hopping on a subframe. That is, one of two slots allocated to one terminal may be allocated in one frequency band, and the other may be allocated to be alternately allocated in the other frequency band. A frequency diversity gain can be obtained by transmitting a control region for one terminal through slots allocated to different frequency bands. In addition, multiple users can be multiplexed by code division multiplexing (CDM).

4 shows a mapping of data in a resource allocation mapper.

Referring to FIG. 4, in the resource allocation mapper, a data symbol is mapped to a time-frequency resource region except for an OFDM symbol to which a reference signal (RS) is mapped. The resource zone includes a plurality of resource elements. Resource elements are defined by OFDM symbols and subcarriers. One data symbol is mapped to one resource element. Data symbols are mapped in a time domain from time indexes 0 to 11 except for two OFDM symbols to which a reference signal is mapped. The time index corresponds to an OFDM symbol. The reference signal is mapped in the frequency domain mapper. The reference signal may be mapped between time indices 2 and 3 and between 8 and 9.

It is assumed that a resource region includes two resource blocks and transmits data A = [a ₀ , a ₁ , ..., a _NA -1] using the resource region. N _A is the length of the first data, that is, the number of data symbols belonging to the first data. Equation 1 shows the mapping of data symbols in the resource allocation mapper.

d (i, j) = a _{f (i, j)}

Here, the data symbols output from the resource allocation mapper are d (i, j), j is 0≤j <M as a time index, i is 0≤i <N as a frequency index, and f (i, j) is a resource. A mapping function that represents the role of the allocation mapper (an integer with M, N> 0).

When the data symbols [a ₀ , a ₁ , ..., a _NA-1 ] are mapped to the resource region by the resource allocation mapper, the mapping function f (i, j) may be represented through the following algorithm.

i = 0, j = 0, k = 0; while (k <N _A ) d (i, j) = a _k j ++ if (j == M) j = 0 i ++ End if end while

D (0,0), d (0,1), d (0,2), ..., d (0, M-1), d (1,0) in the order that data symbols enter the resource allocation mapper , d (1,1), d (1,2), ..., d (1, M-1), d (2,0), ..., d (N-1, M-1) Is mapped.

Hereinafter, a method in which the resource allocation mapper maps two or more multiple data in the allocated resource region will be described.

<Multiple Data Mapping Method 1: When N _A + N _B ≤ N * M>

5 illustrates mapping of multiple data in a resource allocation mapper according to an embodiment of the present invention.

Referring to FIG. 5, a resource region includes two resource blocks, and using the resource region, first data A = [a ₀ , a ₁ , ..., a_N _A -1] and second data B = Assume that [b ₀ , b ₁ , ..., b_N _B -1] is transmitted. N _A is the length of the first data, that is, the number of data symbols belonging to the first data. N _B is the length of the second data, that is, the number of data symbols belonging to the second data. In this case, when the first data is the data originally intended to be transmitted using the resource region and the second data is the data having high importance to be additionally transmitted using the resource region, the second data may be located near the reference signal. Can be. The receiver demodulates a received signal by estimating a channel based on the reference signal. Since data symbols located near the reference signal are less susceptible to changes in the channel state, they can be regarded as reliable data in terms of demodulation. That is, data requiring higher reliability is arranged near the reference signal. When the first data is user data, the second data may be control information related to the user data. There are various types of control information, such as an ACK / NAK signal, a channel quality indicator (CQI), a scheduling request signal, and MIMO control information. Alternatively, when the first data is non-real time data which is relatively less sensitive to time delay, the second data may be real time data such as Voice over Internet Protocol (VoIP).

Length N _A is the first data _{A = [a 0, a 1} , ..., a NA-1] and a length of N _B is the second data _{B = [b 0, b 1} , ..., b NB _{When -1} ] is transmitted through one resource region N × M, the case where N _A + N _B ≦ N × M may be mapped as follows (N _A ≦ N × M is satisfied). N denotes the number of subcarriers in the frequency domain allocated to the terminal, and M denotes the number of OFDM symbols excluding the OFDM symbol carrying the reference signal in the time domain. It is assumed that a resource region allocated to a terminal includes two slots, and a reference signal is mapped to one OFDM symbol in each slot. floor (x) represents the maximum value among integers less than or equal to x.

i = 0, j = 0, k = 0, ia = 0, ib = 0; Create a set P from N _B , N, M P = {p | p = i × M + j} where i = floor (k / 2)% (N) j = 3+ (k% 2) × 6 + floor (floor (k / 2) / N) k = 0,1, ..., N _B -1 while (k <N _A + N _B ) if (if i × M + j is an element of set P) d ( i, j) = b _ib ib ++ else d (i, j) = a _ia ia ++ end if j ++ if (j == M) j = 0 i ++ End if k ++ end while

When the sum of N _A and N _B is equal to or smaller than the resource region N × M, the symbols of the first data and the symbols of the second data may be arranged so as not to overlap each other. The resource allocation mapper may select a position to insert a symbol of the second data from N _B , N, and M (set P). Here, the set P is time indexes 3 and 9 and contains as many resource elements as the number of symbols of the second data. The set P represents an OFDM symbol adjacent to an OFDM symbol to which a reference signal is to be mapped by the frequency domain mapper.

If the symbol of the first data is arranged in the time domain and the mapping position corresponds to the set P, the symbol of the second data is arranged. That is, the set P to which the second data is to be mapped is first defined so that the second data is mapped to an OFDM symbol adjacent to the OFDM symbol to which the reference signal is to be mapped in preference to the first data. When a reference signal is mapped between time indices 2 and 3 and between 8 and 9, since the set P is adjacent to the position where the reference signal is to be mapped, the second data may be referred to as reliable data compared to the first data.

For example, if N = 24, M = 12, N _B = 17, N _A = 24 x 12-17 = 271, as shown, the first data is placed in the A area and the second data is placed in the B area. Is placed. Since the second data arranged in the B region is spread to the frequency domain by the DFT after the resource allocation mapper, it is not necessary to spread the second data into the frequency domain in the resource allocation mapper.

In this example, the position of the set P where the symbols of the second data are placed is followed in time adjacent to the reference signal (the more it is located on the left side in the time domain, the more time advances). It may be determined to advance in time adjacent to the reference signal.

6 illustrates mapping of multiple data in a resource allocation mapper according to another embodiment of the present invention.

Referring to FIG. 6, the first data A having a length N _A = [a ₀ , a ₁ ,..., A _NA-1 ] and the second data having a length N _B B = [b ₀ , b ₁ , When ..., b _{NB -1} ] is transmitted through one resource region N × M, when the size of N _B is larger than that of the resource region, the second data symbol may occupy one more OFDM symbol. have.

For example, when the resource region is N = 12, M = 12, N _B = 30, N _A = 12 × 12-30 = 144, the first data and the second data are determined according to the multiple data mapping method 1. When mapped, the first data is mapped to area A and the second data is mapped to area B as shown.

<Multiple Data Mapping Method 2: N _A + N _B > N × M>

7 illustrates mapping of multiple data in a resource allocation mapper according to another embodiment of the present invention.

Referring to FIG. 7, first data A having a length N _A = [a ₀ , a ₁ ,..., A_N _{A -1} ] and second data having a length N _B B = [b ₀ , b ₁ , When ..., b_N _{B -1} ] is transmitted through one resource region (N × M), N _A + N _B > N × M may be mapped as follows (N _A = N × May be M). It is assumed that a resource region allocated to a terminal includes two slots, and a reference signal is mapped to one OFDM symbol in each slot.

i = 0, j = 0, k = 0, ia = 0, ib = 0; Set T to a value smaller than N _step = floor (N / (N _B / 2)) and set T _H to a value smaller than N _step . Create a set P 'from N _B , N, M P' = {p | p = i × M + j} where i = (floor (k / 2) × N _step + (k% 2) × T _H + T)% N j = 2+ (k% 2) × 6 N _step = floor (N / (N _B / 2)) k = 0,1, ..., N _B -1 while (k <N _A d (i, j) = a _ia ia ++ if (if i × M + j is an element of set P ') d (i, j) = b _ib ib ++ end if j ++ if (j == M) j = 0 i ++ End if k ++ end while

If the sum of N _A and N _B is greater than the resource region N × M, the first data is first mapped to the resource region, and then a puncturing symbol of the first data at a predetermined position (set P ′) is obtained. You can map symbols of data. Here, the set P 'is time indexes 2 and 8 and includes as many resource elements as the number of symbols of the second data. The set P 'represents an OFDM symbol adjacent to an OFDM symbol to which a reference signal is to be mapped by the frequency domain mapper. In order to map the symbol of the second data, the symbol of the resource element to which the first data is mapped is punctured. In order to minimize the influence on the first data, N _steps are given so that the symbols of the second data are distributed in the frequency domain and mapped. Be sure to When a reference signal is mapped between time indices 2 and 3 and between 8 and 9, since the set P 'is adjacent to the position where the reference signal is to be mapped, the second data may be referred to as reliable data compared to the first data.

For example, if N = 24, M = 12, N _B = 18, N _A = 24 × 12 = 288, T = 1, T _H = 0,

P '= {p | p = i × M + j}

where i = (floor (k / 2) × N _step + (k% 2) × 0 + 1)% N

       = {1,1,3,3,5,5,7,7,9,9,11,11,13,13,15,15}

      j = 2+ (k% 2) * 6 = {2,8,2,8,2,8,2,8,2,8,2,8,2,8,2,8,2,8}

N _step = floor (24 / (18/2)) = 2

          k = 0,1, ..., 18-1

P 'is generated as shown in the figure, and the first data is mapped to the area A, and the second data is mapped to the area B as shown. The second data is temporally adjacent to the reference signal and mapped at two subcarrier intervals in the frequency domain according to N _step = 2. The second data is transmitted as more reliable data than the first data.

Here, the position of the set P 'to which the second data is mapped is determined to be temporally adjacent to the reference signal. However, this is merely an example, and the position of the set P' may be determined to be temporally adjacent to the reference signal.

8 illustrates mapping of multiple data in a resource allocation mapper according to another embodiment of the present invention.

Referring to FIG. 8, in the multiple data mapping method 2 of FIG. 7, N = 24, M = 12, N _B = 16, N _A = 24 × 12 = 288, T = 1, and T _H = 2.

P '= {p | p = i × M + j}

where i = (floor (k / 2) × N _step + (k% 2) × 2 + 1)% N

       = {1,3,4,6,7,9,10,12,13,15,16,18,19,21,22,0}

      j = 2+ (k% 2) * 6 = {2,8,2,8,2,8,2,8,2,8,2,8,2,8,2,8}

N _step = floor (24 / (16/2)) = 3

          k = 0,1, ..., 16-1

P 'is generated as shown in the figure, and the first data is arranged in the area A, and the second data is arranged in the area B as shown.

In the above description, it has been described that two data are transmitted using one resource region. However, this is not a limitation, and two or more types of data may be transmitted through the resource region. For example, when an uplink resource region allocated from a base station is an uplink shared channel (PUSCH), the first data is user data, and the second data is an ACK / NACK signal, a CQI, a PMI, Various control information such as RI may be transmitted.

<Apply multiple data mapping methods 1 and 2 together>

9 illustrates mapping of multiple data in a resource allocation mapper according to another embodiment of the present invention.

Referring to FIG. 9, the resource allocation mapper may apply three data mapping methods 1 and 2 together to map three data to one resource region. First data _A of length N _A = [a ₀ , a ₁ , ..., a_N _{A -1} ], second data of length N _B B = [b ₀ , b ₁ , ..., b_N _{B -1} ] and third data C = [c ₀ , c ₁ , ..., c_N _{C -1} ], of length N _C , are transmitted. The multiple data mapping method 1 may be applied between the first data and the second data, and the multiple data mapping method 2 may be applied between the first data and the third data. In this case, the second data and the third data may be mapped so as to follow in time adjacent to the reference signal so that the second data and the third data do not overlap with each other, and the third data may be mapped so as to advance in time adjacent to the reference signal. Alternatively, the second data may be mapped to be temporally adjacent to the reference signal, and the third data may be mapped to be temporally adjacent to the reference signal.

For example, the first data is user data, the second data is first control information such as CQI, PMI, RI, and the like, and the third data is second control information such as an ACK / NACK signal. When N = 12 and M = 12, the first control information is N _B = 45, the second control information is N _C = 14, and when T = 0 and T _H = 0, P of the first control information is

P = {p | p = i × 12 + j}

where i = floor (k / 2)% (12) = {0,0,1,1,2,2,3,3, ..., 21,21,22}

      j = 3+ (k% 2) × 6 + floor (floor (k / 2) / 24) = {3,9, ..., 3,9 (22 times), 3}

      k = 0,1, ..., 45-1

And P 'of the second control information is

P '= {p | p = i × 12 + j}

where i = (floor (k / 2) × N _step + (k% 2) × 0 + 0)% N

       = {0,0,3,3,6,6,9,9,12,12,15,15,18,18}

      j = 2+ (k% 2) × 6 = {2,8,2,8,2,8,2,8,2,8,2,8,2,8}

N _step = floor (24 / (14/2)) = 3

          k = 0,1, ..., 14-1

As shown in the drawing, user data is mapped to area A, first control information is mapped to area B, and second control information is mapped to area C as shown. The first control information and the second control information are transmitted as more reliable data than the user data.

The algorithms described above are exemplary only and not limiting. Although the data symbols have been described as being preferentially arranged in the time domain, the data symbols may be preferentially arranged in the frequency domain. In addition, the direction in which the data symbols are arranged may be variously determined such that the symbols of the first data are preferentially arranged in the time domain and the symbols of the second data and the symbols of the third data are preferentially arranged in the frequency domain.

All of the above functions may be performed by a processor such as a microprocessor, a controller, a microcontroller, an application specific integrated circuit (ASIC), or the like according to software or program code coded to perform the function. The design, development and implementation of the code will be apparent to those skilled in the art based on the description of the present invention.

Although the present invention has been described above with reference to the embodiments, it will be apparent to those skilled in the art that the present invention may be modified and changed in various ways without departing from the spirit and scope of the present invention. I can understand. Therefore, the present invention is not limited to the above-described embodiment, and the present invention will include all embodiments within the scope of the following claims.

1 is a block diagram illustrating a wireless communication system.

2 is a block diagram illustrating an example of a transmitter using SC-FDMA.

3 shows an example of a subframe.

4 shows a mapping of data in a resource allocation mapper.

5 illustrates mapping of multiple data in a resource allocation mapper according to an embodiment of the present invention.

6 illustrates mapping of multiple data in a resource allocation mapper according to another embodiment of the present invention.

7 illustrates mapping of multiple data in a resource allocation mapper according to another embodiment of the present invention.

8 illustrates mapping of multiple data in a resource allocation mapper according to another embodiment of the present invention.

9 illustrates mapping of multiple data in a resource allocation mapper according to another embodiment of the present invention.

Claims (10)

In the method of mapping data to radio resources in a wireless communication system, Mapping first data in successive OFDM symbols on a subframe comprising a plurality of OFDM symbols and a plurality of subcarriers; Mapping second data in a line on a frequency axis on a first OFDM symbol selected on the subframe; And And mapping the second data in a line on a frequency axis on a second OFDM symbol spaced apart from the first OFDM symbol. The method of claim 1, wherein the first data is not mapped to the first OFDM symbol and the second OFDM symbol, and only the second data is mapped. The radio resource mapping method of claim 1, wherein the first data is mapped to the first OFDM symbol and the second OFDM symbol, and then punctured to map the second data. The method of claim 1, wherein the second data is mapped to adjacent subcarriers on one OFDM symbol. The method of claim 1, wherein the second data is mapped to subcarriers spaced at regular intervals on one OFDM symbol. The radio resource mapping method of claim 1, further comprising performing an IFFT after performing a DFT in an OFDM symbol unit. The method of claim 1, wherein a reference signal is mapped to at least one of an OFDM symbol adjacent to the first OFDM symbol and an OFDM symbol adjacent to the second OFDM symbol. 8. The method of claim 7, further comprising mapping third data in a line on a frequency axis on another OFDM symbol adjacent to the OFDM symbol to which the reference signal is mapped. A resource allocation mapper for mapping first data to consecutive OFDM symbols on a subframe including a plurality of OFDM symbols and mapping second data to OFDM symbols spaced apart from each other; A DFT unit performing a DFT on the basis of OFDM symbols on the radio resource to which the first data and the second data are mapped; A frequency domain mapper which assigns data symbols for the first data and the second data to subcarriers after performing the DFT; And And an IFFT unit configured to perform IFFT on the subcarriers to which the first data or the second data are allocated. The transmitter of claim 9, wherein the frequency domain mapper maps a reference signal to an OFDM symbol adjacent to the OFDM symbol to which the second data is mapped.

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