KR20100033908A - Stbc based transmission method considering the number of symbols in a slot - Google Patents

Abstract

PURPOSE: An STBC based transmission method considering the number of symbols in a slot is provided to efficiently implement transmission diversity while maintaining CM(Cubic Metric) characteristic. CONSTITUTION: A transmission symbol pairs continuous two symbol units in each sub frame by STBC(Spatial Time Block Coding) method. The transmission symbol is mapped with a frequency domain by slot unit and transmitted. One sympol in a slot, of which symbol number except for symbols for reference signal transmission is odd, is not paired by the STBC method. If the transmission symbol is transmitted through one symbol not paired by the STBC method, the transmission symbol is transmitted through a first antenna and conjugate symbol of the particular symbol is transmitted through a second antenna.

Description

STBC based signal transmission method considering number of symbols in slot {STBC BASED TRANSMISSION METHOD CONSIDERING THE NUMBER OF SYMBOLS IN A SLOT}

The following description relates to a technique of applying STBC in consideration of the number of symbols in a slot and a signal transmission method using the same in a wireless communication system.

Peak power to average power ratio (PAPR) is related to the dynamic range that a power amplifier must support on the transmitter side, and the cubic metric (CM) value can represent the numerical value represented by the PAPR. Another figure.

In general, a single carrier signal shows better performance than a multi carrier signal in CM or PAPR. In the 3GPP LTE (3rd Generation Partnership Project Long Term Evolution) system, due to the above-described PAPR / CM problem, the SC-FDMA (S-FDMA) is used to have a single carrier characteristic for uplink transmission from a UE to a base station (Node B or eNB). Single Carrier Frequency Divisional Multiple Access) is used. In addition, in 3GPP LTE-A (3rd Generation Partnership Project Long Term Evolution Advanced), MIMO (Multi-Input Multi-Output) transmission method using the SC-FDMA is discussed to maintain good CM characteristics.

The MIMO scheme is briefly described below.

In short, MIMO stands for "Multi-Input Multi-Output", and it is far from having used one transmission antenna and one reception antenna, and improves transmission and reception data efficiency by adopting multiple transmission antennas and multiple reception antennas. Say how you can make it happen. In other words, MIMO technology is an application of a technique of gathering and completing fragmented pieces of data received from multiple antennas without relying on a single antenna path to receive one entire message. Such a MIMO technology can increase the data rate in a specific range or increase the system range for a specific data rate. That is, MIMO technology is a next generation mobile communication technology that can be widely used in mobile communication terminals and repeaters.

1 is a diagram illustrating a configuration of a general multi-antenna system.

As shown in FIG. 1, when the number of antennas is simultaneously increased in a transmitting / receiving stage, the theoretical channel transmission capacity increases in proportion to the number of antennas, unlike when a plurality of antennas are used only in a transmitter or a receiver, thereby dramatically improving frequency efficiency. Can be improved.

The research trends related to multi-antennas to date include information theory aspects related to calculation of multi-antenna communication capacity in various channel environments and multiple access environments, wireless channel measurement and model derivation of MIMO system, and transmission reliability and transmission rate improvement. Active research is being conducted from various viewpoints, such as the study of space-time signal processing technology.

MIMO technology uses a "spatial diversity" scheme that improves transmission reliability by using symbols that pass through various channel paths, and a "spatial diversity" which improves a transmission rate by simultaneously transmitting a plurality of data symbols using multiple transmit antennas. "Spatial multiplexing". In addition, researches on how to appropriately combine these two methods to obtain the advantages of each are being studied in recent years.

The following is a more detailed description of each method.

First, in the case of the spatial diversity scheme, there is a space-time trellis code sequence scheme that simultaneously uses a space-time block code sequence and a diversity gain and a coding gain. In general, the bit error rate improvement performance and the code generation degree of freedom are excellent in the trellis code method, but the operation complexity is simple in space-time block code. The spatial diversity gain can be obtained by an amount corresponding to the product of the number of transmit antennas and the number of receive antennas. On the other hand, the "space-time coding method" can be regarded as "frequency-space coding method" in consideration of the time-domain new frequency domain, and the same coding method may be used as it is.

Secondly, the spatial multiplexing technique is a method of transmitting different data strings at each transmitting antenna, and at the receiver, mutual interference occurs between data transmitted simultaneously from the transmitter. The receiver removes this interference using an appropriate signal processing technique and receives it. Noise cancellation methods used here include maximum likelihood receiver, ZF receiver, MMSE receiver, D-BLAST, V-BLAST, and so on, especially when the transmitter can know the channel information. Decomposition: SVD) can be used.

Third, there is a combined technique of spatial diversity and spatial multiplexing as described above. If only the spatial diversity gain is obtained, the performance improvement gain is gradually saturated as the diversity order is increased, and if only the spatial multiplexing gain is taken, transmission reliability is deteriorated in the wireless channel. In order to solve this problem, methods for obtaining both gains have been studied. Among them, there are a space-time block code (Double-STTD) and a space-time BICM (STBICM).

In the MIMO system as described above, the transmission efficiency can be increased by multiplying the transmission signal through each antenna by weight, and multiplying the transmission signal by the decisive value is referred to as precoding.

In general precoding, since information signals corresponding to several layers are multiplexed and transmitted from one antenna point of view, they can be viewed as a kind of multi-carrier signal. That is, it can be seen that deterioration of CM characteristics of the transmission signal occurs through precoding.

Considering the reason why the CM value is degraded by precoding, the CM value may be deteriorated when a single carrier signal having good CM characteristics is overlapped at the same time. Therefore, in the SC-FDMA system, when the information from multiple layers is mapped to the smallest number of single carrier signals and multiplexed through one physical antenna, transmission of the information may maintain a good CM.

Meanwhile, among the above-described MIMO schemes, transmission diversity is a technique that performs a special processing when transmitting information, so that reception is somewhat reliable through transmission diversity on the receiving side even if a part of the channel falls into an unfavorable environment. . Transmit diversity is mainly used when a terminal is located at a cell edge, and may be used in a situation where a channel changes quickly and thus it is difficult to perform channel dependent scheduling, or when a channel change is sudden. In addition, there are various environments and conditions in which the transmission diversity scheme may be used.

The present invention proposes various methods for implementing transmit diversity while maintaining the above-described CM characteristics.

Specifically, while implementing transmission diversity using the STBC scheme, we propose a method of efficiently applying STBC in consideration of the number of symbols in each subframe / slot in the SC-FDMA system.

In addition, the present invention proposes a method of maintaining good CM characteristics by efficiently mapping the subcarriers by applying STBC to each symbol in a four-antenna system.

In an embodiment of the present invention for solving the above problems, two or more transmit antennas are used in a mobile communication system using a structure in which one subframe includes two slots and each slot includes a plurality of symbols. A method of transmitting a signal, the method comprising: pairing a transmission symbol in a spatial time block coding (STBC) scheme in units of two consecutive symbols in each subframe; And transmitting the transmission symbols by mapping them in the frequency domain in units of slots, wherein one symbol in the slot having an odd number of symbols excluding symbols for reference signal transmission is not paired with the STBC scheme. We propose a signal transmission method.

In this case, when transmitting a transmission symbol through one symbol that is not paired by the STBC method, a specific symbol may be transmitted through a first antenna and a conjugate type symbol of the specific symbol may be transmitted through a second antenna. In this case, the first antenna and the second antenna may be transmitted in the same form.

In addition, the frequency domain mapping may include performing frequency hopping on a slot basis.

In addition, when the mobile communication system transmits a signal using an extended cyclic prefix of the 3GPP system, each slot includes six symbols, and one symbol in each slot is a first type reference signal. It may be pre-allocated for transmission.

The method may further include transmitting a second type reference signal through one symbol in a specific slot, in which case the second type reference signal is included in a slot other than the specific slot among symbols in the specific slot. It may be transmitted through a symbol corresponding to one symbol not paired by the STBC scheme.

In addition, the one symbol for transmitting the second type reference signal may be located between symbols for transmitting the first type reference signal in one subframe.

Meanwhile, in another embodiment of the present invention for solving the above problems, two or more transmissions are used in a mobile communication system using a structure in which one subframe includes two slots and each slot includes six symbols. A method of transmitting a signal using an antenna, wherein one symbol for transmitting a data modulation reference signal in a first type slot in which a sounding reference signal is transmitted through one symbol Pairing a transmission symbol mapped to four symbols except for a Spatial Time Block Coding (STBC) method in units of two consecutive symbols; STBC of four symbols, which are mapped to five symbols except one symbol for transmission of the reference signal for data modulation, in a second type slot in which the sounding reference signal is not transmitted, in units of two consecutive symbols Pairing by a Spatial Time Block Coding (Spatial Time Block Coding) scheme; And it proposes a signal transmission method comprising the step of transmitting by transmitting the transmission symbol in the frequency unit in the slot unit.

In this case, one specific subframe includes the first type slot and the second type slot, and the transmission symbols that are not paired by the STBC scheme in the second type slot may include a reference signal for data modulation in the subframe. It may be located between the transmitted symbols.

According to the present invention as described above, it is possible to efficiently implement transmit diversity while maintaining good CM characteristics.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following detailed description, together with the accompanying drawings, is intended to illustrate exemplary embodiments of the invention and is not intended to represent the only embodiments in which the invention may be practiced.

The following detailed description includes specific details in order to provide a thorough understanding of the present invention. However, one of ordinary skill in the art appreciates that the present invention may be practiced without these specific details. In some instances, well-known structures and devices are omitted or shown in block diagram form, centering on the core functions of each structure and device, in order to avoid obscuring the concepts of the present invention. In addition, the same components will be described with the same reference numerals throughout the present specification.

As described above, the present invention proposes various methods for implementing transmit diversity while maintaining good CM characteristics.

Among various methods that can be implemented, one embodiment of the present invention looks at a method of efficiently applying STBC in an SC-FDMA system. For this purpose, a transmission method using Spatial Time Block Coding (STBC) or more fundamentally, Alamouti code will be described.

In the transmit diversity (hereinafter, simply referred to as "Tx Div") structure using the Alamouti code, the receiver may be more easily interpreted by changing the receiver into an equivalent receiver as shown in FIG. 2.

2 illustrates an equivalent receiver structure for easily describing a system using an Alamouti code.

That is, in a diversity transmission method using an Alamouti code, more efficient mathematical modeling is possible when conjugate conjugates are applied to the second received signal for mathematical modeling of the received signal. FIG. 2 illustrates that a received signal may be represented in a matrix form by taking a complex conjugate of a receiver corresponding to time 2 or frequency 2. Hereinafter, specific mathematical modeling using the same will be described.

Here, two kinds of matrixes of Alamouti codes can be considered.

In the matrixes of Equations 1 and 2, each column represents time or frequency, and each row represents an antenna. Specifically, the matrix of Equation 1 is a general formula proposed by Alamouti in his paper, and Equation 2 represents a matrix used in the 3GPP LTE standard. That is, Equation 2 is a matrix reconstructed so that the signal transmitted through the antenna 1 in the Single Input Single Output (SISO) method in which only one antenna is used and the signal transmitted through the antenna 1 in the Alamouti method are the same.

For reference, in the above equation, each column represents a time when the Alamouti code is used as a type of STBC (Space Time Block Code), and when each column represents a frequency, the Alamouti code represents the SFBC (Space Frequency). Block Code) is used as one type.

Now look at in detail with reference to FIG.

In general, the reception signal in the case where the Alamouti transmission diversity is used can be expressed as follows. Hereinafter, a description will be given on the assumption that the STBC in which the columns of Equations 1 and 2 represent time, but the same mathematical modeling is possible in the case of SFBC in which the columns of Equations 1 and 2 represent frequencies. . The signals of the time 1 and the time 2 are represented by y1 and y2 as follows.

In Equation 3, n ₁ and n ₂ represent noise generated by each receiving antenna, s ₁ and s ₂ represent transmission signals at time 1 and time 2, and h ₁ and h ₂ are transmission channel values for each antenna. Indicates.

At this time, as shown in FIG. 2, if the complex conjugate of the received signal of the second time is taken as follows.

The received signal model shown in Equation 4 is expressed in a vector and a matrix.

는 유효 채널을 나타낸다.here

Denotes an effective channel.

Such STBC can give diversity gain to a transmission signal in a MIMO system. However, in order to apply the above-described STBC, it is required to be paired in units of two transmission symbols in each transmission unit in the time domain. However, in certain cases, the number of symbols transmitted in each time domain transmission unit is odd. Application of STBC can be difficult.

To this end, the structure of the transmission unit in the SC-FDMA system will be described below.

3 is a diagram illustrating the structure of one subframe in an SC-FDMA system.

Specifically, FIG. 3 shows a subframe structure in a mode using normal CP. One subframe consists of two slots. In addition, when using a normal CP as shown in Figure 3, it is composed of 14 SC-FDMA symbols, that is, 7 SC-FDMA symbols per slot.

On the other hand, in case of using Extended CP, one subframe includes 12 SC-FDMA symbols, that is, 7 SC-FDMA symbols per slot.

In the case of using a normal CP and an extended CP, one SC-FDMA symbol among symbols included in each slot is used for a reference signal transmission. In this case, the reference signal may be referred to as a data modulation reference signal (DMRS) to distinguish it from a sounding reference signal (SRS). Also, depending on the situation, the first or last symbol may not be used.

4 is a diagram illustrating a structure of a transmitter for transmitting signals in the SC-FDMA scheme.

As shown in FIG. 4, SC-FDMA information is first mapped to a frequency domain through a Discrete Fourier Transform (DFT). Thereafter, the information mapped in the frequency domain takes an Inverse Fast Fourier Transform (IFFT) and attaches a CP to generate one SC-FDMA symbol. As such, the reason why the IFFT is performed after performing the DFT on the information signal is that the DFT and the IFFT cancel each other's influences, so that the information may be transmitted as if it is transmitted through a single carrier.

Since a signal transmitted as a single carrier signal has a small CM value, the maximum transmit power that can be transmitted may be higher without distorting the signal as much as possible in a given power amplifier.

A method of applying and transmitting STBC according to an embodiment of the present invention will be described below using the above-described SC-FDMA subframe structure and transmission scheme. First, the case of a two antenna system is demonstrated.

In applying the STBC to the SC-FDMA system in this embodiment, it is proposed to apply the Alamouti code on the time axis to keep the CM value low.

FIG. 5 is a diagram for describing a method of transmitting a signal using a normal CP mode in a two antenna system.

According to the present embodiment, when two Tx antennas exist, a symbol mapped to a specific subcarrier is _denoted as S _x (x = 1, 2, 3, .. 12), and is transmitted in the manner shown in FIG. 5. Suggest to do.

Specifically, in a system using a general CP, a total of seven SC-FDMA symbols exist in each slot, and one symbol in each slot is used for transmitting a reference signal. Accordingly, it is proposed to pair and transmit a transmission symbol transmitted through six symbols except for one symbol for reference signal transmission by two consecutive STBC schemes.

However, when the sounding reference signal, that is, the SRS is additionally transmitted in addition to the above-described reference signal, that is, the DM RS, the number of symbols in the subframe may vary.

FIG. 6 is a diagram for explaining an example in which an SRS is transmitted through a specific symbol in a subframe.

As illustrated in FIG. 6, in the case of a subframe in which SRS is additionally transmitted through one symbol in a subframe, the second slot includes an odd number of symbols. In one embodiment of the present invention, in this case, six symbols except for a symbol in which the RS is transmitted in the first slot perform STBC pairing by two adjacent symbols, except for two symbols in which the RS and SRS are transmitted in the second slot. It is proposed that four symbols out of five symbols are hopped by adjacent two symbols for STBC pairing, and the last remaining one symbol does not perform STBC pairing.

6 shows how S ₁₁ is transmitted as an unpaired symbol of STBC. In detail, FIG. 6 illustrates an example in which S ₁₁ without STBC pairing is transmitted to the first antenna (Tx Antenna # 1) and the second antenna (Tx Antenna # 2) in the same manner.

FIG. 7 is a diagram for describing a method of transmitting a symbol not paired with an STBC in a conjugate form through a second antenna in a subframe in which an SRS is transmitted according to another embodiment of the present invention.

In the present embodiment illustrated in FIG. 6, when a total of 13 SC-FDMA symbols are transmitted in one subframe due to SRS transmission, the last SC-FDMA of symbols S ₁ to S ₁₁ transmitted through the first antenna is transmitted. Except for the symbols, it can be seen that all the symbols transmitted to the second antenna are in the form of conjugates of the symbols transmitted to the first antenna. Therefore, in another embodiment of the present invention, for the purpose of easier implementation, when the last symbol S ₁₁ , that is, the SC-FDMA symbol that is not STBC paired, is also transmitted through the second antenna as shown in FIG. 7. It is proposed to transmit in complex form.

Of course, the unpaired symbols of STBC are not necessarily the last SC- FDMA symbol in the subframe. In addition, in some cases, symbols that are not STBC paired may be located near the RS to obtain channel estimation gains.

In the following description, a case of a two antenna system using an extended CP will be described.

8 and 9 are diagrams for explaining a method of transmitting a signal in the STBC scheme in a two-antenna system using an extended CP.

As shown in FIGS. 8 and 9, 12 SC-FDMA symbols exist in one subframe, and 6 SC-FDMA symbols exist per slot. As shown in FIG. 8, when the extended CP is used, two adjacent symbols for 10 symbols in a subframe except one symbol for RS transmission per slot (that is, two symbols in a subframe) as shown in FIG. 8. STBC pairing can be performed with each other. In addition, as shown in FIG. 9, eight symbols out of nine symbols except one symbol for RS transmission per slot (that is, two symbols in a subframe) and one symbol for SRS transmission in a subframe are adjacent to each other. STBC pairing is performed by two symbols, and the remaining one symbol shows a method of transmitting a transmission symbol without performing STBC pairing. 9 shows S ₉ as a symbol transmitted without being paired with STBC.

However, as shown in FIGS. 8 and 9, when two STBC pairs of SC-FDMA symbols excluding RS are sequentially sequentially, an STBC pair may be generated at a slot boundary. In consideration of the fact that frequency hopping may be performed in a 3GPP system based on a slot unit or a subframe unit, it is not preferable to generate an STBC pair across a slot boundary.

10 illustrates an example in which frequency hopping is performed on a slot basis.

As shown in FIG. 10, when a transmission signal is transmitted through frequency hopping in units of slots, the STBC pairs generated across slot boundaries in FIGS. 8 and 9 are transmitted through different frequency domains. In this case, since the channel coefficient experienced by each symbol in the STBC pair is different, reception performance may be degraded.

Accordingly, one preferred embodiment of the present invention proposes a method for transmitting signals by performing STBC in the following manner.

11 and 12 are diagrams for explaining a method of transmitting a signal by applying STBC when using an extended CP according to an embodiment of the present invention.

That is, as shown in FIG. 11, in the present embodiment, when the extended CP is used so that no STBC pair is generated at each SC-FDMA slot boundary, the last SC-FDMA symbol of each slot does not perform STBC pairing. . In addition, as shown in FIG. 12, in a subframe in which the SRS is transmitted, the SRS may be set to be transmitted through any one of the symbols that are not the STBC pairing of FIG. 11. Preferably, as shown in FIG. 12, a symbol S ₅ transmitted without STBC pairing may be positioned between RSs to obtain a channel estimation gain.

In addition, in one embodiment of the present invention, the schemes of FIGS. 9 and 10 and the schemes of FIGS. 11 and 12 may be flexibly applied. That is, when slot-frequency frequency hopping is not performed, as shown in FIGS. 9 and 10, STBC pairing is also performed across the slot boundary, and when slot-frequency frequency hopping is not performed, as shown in FIGS. 11 and 12. As described above, when the number of symbols excluding symbols for RS and SRS transmission per slot is odd, one symbol may be applied so that STBC pairing is not performed.

The above-described transmission scheme is suitable for transmission through a physical uplink shared channel (PUSCH), but may be applied by the same principle to transmit other channel signals.

13 through 15 illustrate a method of transmitting a signal in a two antenna system using an extended CP according to still another embodiment of the present invention.

That is, in the embodiments shown in FIGS. 11 and 12, all of the symbols transmitted through the second antenna for simple implementation are transmitted in pairs. However, as shown in FIGS. 13 and 14, a symbol transmitted through the second antenna may also be transmitted in the same form as a symbol transmitted through the first antenna.

In addition, in the case of a subframe in which the SRS is not transmitted in the two-antenna system using the extended CP as shown in FIG. 15, there may be two symbols to which STBC pairing is not applied. In this case, one symbol (for example, S ₅ ) is the same symbol is transmitted through the first antenna and the second antenna, and another symbol (for example, S ₁₀ ) is a symbol transmitted through the second antenna is transmitted through the first antenna It can also be set to be transmitted in the form of a pair of symbols.

In the following description, a case of a four antenna system will be described.

A terminal having four transmit antennas can transmit signals using 4 Tx transmit diversity. The Alamouti code, however, can be used with two Tx antennas, but is not known to extend to a 4 Tx antenna system.

Therefore, in one embodiment of the present invention, in the 4 Tx system, STBC is applied by using the two antennas, and the frequency selective transmit diversity (FSTD) is performed between the two Tx antenna pairs. Suggest to apply.

Since it is important to keep the CM value as it is during PUSCH transmission, it is important to keep the CM low even when using the FSTD. As described above, a method of acquiring diversity gain while keeping the CM low is as follows.

16 and 17 are diagrams for explaining a method of obtaining diversity gain while maintaining a good CM characteristic in a four antenna system according to an embodiment of the present invention.

Specifically, the STBC applied by the 2 Tx system may be applied to each group by grouping data symbols to be transmitted. In this case, when symbols are mapped to subcarriers through IFFT for each group, it is proposed to arrange the symbols transmitted for each antenna in each group in an interlaced structure.

For example, it is assumed that antennas 1 and 2 are grouped into one group, and antennas 3 and 4 are grouped into another group. In this case, the above-described STBC method is applied to antennas 1 and 2, and when symbols are mapped to subcarriers for each antenna, antennas 1 and 2 only have data symbols corresponding to odd subcarriers within the bandwidth where data is transmitted. And map the subcarriers corresponding to even-numbered subcarriers. On the other hand, STBC may be applied to antennas 3 and 4, and zeros may be filled in odd-numbered subcarriers, and data signals may be transmitted by mapping data symbols to even-numbered subcarriers. In this case, information transmitted to antennas 1 and 2 and information transmitted to antennas 3 and 4 may be set to be data of different parts encoded and transmitted at once.

The detailed description of the preferred embodiments of the invention disclosed as described above is provided to enable any person skilled in the art to make and practice the invention. Although the above has been described with reference to the preferred embodiments of the present invention, those skilled in the art will variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. I can understand that you can.

Accordingly, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Each embodiment of the present invention as described above is suitable for application to 3GPP series systems, in particular 3GPP LTE-A systems. However, in some cases, the same principle may be applied to other wireless communication systems using the same subframe structure.

1 is a diagram illustrating a configuration of a general multi-antenna system.

2 illustrates an equivalent receiver structure for easily describing a system using an Alamouti code.

3 is a diagram illustrating the structure of one subframe in an SC-FDMA system.

4 is a diagram illustrating a structure of a transmitter for transmitting signals in the SC-FDMA scheme.

FIG. 5 is a diagram for describing a method of transmitting a signal using a normal CP mode in a two antenna system.

FIG. 6 is a diagram for explaining an example in which an SRS is transmitted through a specific symbol in a subframe.

FIG. 7 is a diagram for describing a method of transmitting a symbol not paired with an STBC in a conjugate form through a second antenna in a subframe in which an SRS is transmitted according to another embodiment of the present invention.

8 and 9 are diagrams for explaining a method of transmitting a signal in the STBC scheme in a two-antenna system using an extended CP.

10 illustrates an example in which frequency hopping is performed on a slot basis.

11 and 12 are diagrams for explaining a method of transmitting a signal by applying STBC when using an extended CP according to an embodiment of the present invention.

13 to 15 illustrate a method of transmitting a signal in a two antenna system using an extended CP according to still another embodiment of the present invention.

16 and 17 are diagrams for explaining a method of obtaining diversity gain while maintaining a good CM characteristic in a four antenna system according to an embodiment of the present invention.

Claims (9)

A method for transmitting a signal using two or more transmit antennas in a mobile communication system using a structure in which one subframe includes two slots and each slot includes a plurality of symbols, Pairing the transmission symbols by a spatial time block coding (STBC) scheme in units of two consecutive symbols in each subframe; And Mapping the transmission symbol to a frequency domain in units of slots and transmitting the same; One symbol in the slot having an odd number of symbols excluding symbols for reference signal transmission is not paired by the STBC method. The method of claim 1, When transmitting a transmission symbol through one symbol that is not paired by the STBC scheme, Transmitting a specific symbol through a first antenna and transmitting a conjugate type symbol of the specific symbol through a second antenna. The method of claim 1, When transmitting a transmission symbol through one symbol that is not paired by the STBC scheme, And transmitting the same symbol through the first antenna and the second antenna. The method of claim 1, The frequency domain mapping step includes performing frequency hopping on a slot basis. The method of claim 1, When the mobile communication system transmits a signal using an extended cyclic prefix of the 3GPP system, Each slot comprises six symbols, one symbol in each slot pre-allocated for first type reference signal transmission. The method of claim 5, Further transmitting the second type reference signal through one symbol in a specific slot, The second type reference signal is transmitted through a symbol corresponding to one symbol not paired by the STBC scheme in a slot other than the specific slot among symbols in the specific slot. The method of claim 6, And the one symbol for transmitting the second type reference signal is located between symbols for transmitting the first type reference signal in one subframe. A method for transmitting signals using two or more transmit antennas in a mobile communication system using a structure in which one subframe includes two slots and each slot includes six symbols, A transmission symbol mapped to four symbols except one symbol for transmitting a data modulation reference signal in a first type slot in which a sounding reference signal is transmitted through one symbol Pairing in a continuous time block coding (STBC) scheme in units of two consecutive symbols; STBC of four symbols, which are mapped to five symbols except one symbol for transmission of the reference signal for data modulation, in a second type slot in which the sounding reference signal is not transmitted, in units of two consecutive symbols Pairing by a Spatial Time Block Coding (Spatial Time Block Coding) scheme; And And transmitting the transmission symbol by mapping the transmission symbol to a frequency domain on a slot basis. The method of claim 8, One particular subframe includes the first type slot and the second type slot, The transmission symbols which are not paired in the STBC scheme in the second type slot are located between symbols in which the data modulation reference signal in the subframe is transmitted.

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