KR20070067835A - Method for transmitting and receiving data using a plurality of subcarriers - Google Patents

Abstract

A method for transmitting and receiving data using a plurality of sub carriers is provided to improve a usage efficiency of a limited wireless resource by allocating the wireless resource to a downlink. A method for transmitting and receiving data using a plurality of sub carriers includes the steps of: receiving a data signal from a plurality of transmission terminals to which the same wireless resource is allocated through a plurality of sub carriers; receiving the data signal having a pilot signal according to a pilot pattern which identifies the plurality of transmission terminals; and acquiring the data signal of each terminal by identifying the data signal of each terminal from the received data signal through the pilot signal. The plurality of transmission terminals transmits the data signal by a spatial multiplexing process at a specific time period. Some of the plurality of transmission terminals transmit the same data signal at the rest time period. The other transmission terminals change a phase of the data signal, and transmit the changed signal.

Description

Method for transmitting and receiving data using a plurality of subcarriers

1 is a diagram showing the structure of the transmission and reception side used in the prior art and the present invention.

2 is a diagram illustrating the allocation of radio resources according to the prior art.

3 is a view showing the configuration of a data frame in a conventional OFDMA wireless communication system.

4 is a view for explaining the operation of the prior art of allocating uplink radio resources to a terminal using a common DL-MAP.

5 is a diagram illustrating allocation of uplink radio resources in an OFDM / OFDMA system according to the present invention.

6 is a diagram illustrating a transmission scheme according to an embodiment of the present invention.

7 is a diagram illustrating a basic allocation unit of radio resources transmitted through uplink of an OFDM / OFDMA system.

8A is a diagram illustrating a pilot pattern in which time and frequency are different for each user according to the present invention.

8B is a diagram illustrating a pilot pattern using different orthogonal codes for different users according to the present invention.

FIG. 8C is a signal value table assigned to each pilot of FIGS. 8A and 8B.

FIG. 9 illustrates a combination of pilot patterns configuring an uplink data burst according to the present invention.

10 is a view showing the operation of the CSM method using a general DL-MAP according to an embodiment of the present invention.

The present invention relates to an Orthogonal Frequency Division Multiplexing Access (hereinafter, referred to as OFDMA) system, and more particularly, to a radio resource allocation method of OFDMA.

Orthogonal Frequency Division Multiplexing (OFDM) is a method in which a high speed serial signal is separated into a plurality of low speed parallel signals, and then modulated into a respective orthogonal subcarrier to transmit / receive. Thus, orthogonal subcarriers divided into narrow bands experience flat fading and thus have excellent characteristics in frequency selective fading channels. In addition, the transmit end preserves orthogonality between subcarriers using a simple method such as guard interval insertion so that the receiver does not require a complicated equalizer or a rake receiver in DS-CDMA (Direct Sequence-Code Division Multiplexing Access) scheme. do. Due to these excellent characteristics, the OFDM method is adopted as a standard modulation method in digital broadcasting, wireless LAN such as IEEE 802.11a or HIPERLAN, fixed broadband wireless access such as IEEE 802.16, and UMTS (Universal Mobile Telecommunications System). ) Has been considered as one of the applicable technologies of modulation / demodulation / multiple access method. Currently, various multiple access schemes based on OFDM have been actively studied. Among them, the OFDMA scheme is actively studied and studied as a candidate technology for achieving next-generation mobile communication in which user demand such as high-speed multimedia service is rapidly increased. The OFDMA method is a two-dimensional access method combining time division access and frequency division access technology.

1 is a diagram showing the structure of the transmission and reception side used in the prior art and the present invention. When input data is input, channel coding is performed to add additional bits to prevent the data from being distorted in the channel. The channel coding may be a turbo code or an LDPC code. The operation of mapping the bit stream on which the channel coding is performed to a predetermined symbol is performed, and the symbol mapping may be performed by QPSK, 16 QAM, or the like. The data symbol undergoes subchannel modulation mapped to a plurality of subcarriers transmitting the symbol. The signal subjected to the subchannel modulation is carried on the carrier in the time domain through the IFFT, and is transmitted to the wireless channel through filtering and analog conversion. The receiving end reverses the operation of the transmitting end.

2 is a diagram illustrating the allocation of radio resources according to the prior art.

As shown in FIG. 2, in general, a wireless communication system uses radio resources of a limited uplink / downlink for different users. However, there are limitations on how multiple users share the resources allocated to one user. That is, in the 802.16e system, there is Collaborative Spatial Multiplexing (CSM). In the proposed scheme, only simple criteria for selecting two users forming channels orthogonal to each other are presented. That is, it is common not to assign two or more users to the same resource at the same time.

3 is a view showing the configuration of a data frame in a conventional OFDMA wireless communication system. In FIG. 3, the horizontal axis represents a time axis and a symbol unit, and the vertical axis represents a frequency axis and a subchannel unit. The subchannel means a bundle of a plurality of subcarriers. Specifically, in the OFDMA physical layer, active carriers are divided into groups and transmitted to different receivers for each group. The group of carriers transmitted to such a receiver is called a subchannel. In this case, carriers constituting each subchannel may be adjacent to each other or spaced at equal intervals.

Slots assigned to each user are defined by data regions in two-dimensional space, as shown in FIG. 3, which is a set of contiguous subchannels assigned by bursts. . One data area in OFDMA is shown as a rectangle, determined by time coordinates and subchannel coordinates, as shown in FIG. Such a data area may be allocated to an uplink of a specific user or a base station may transmit a data area to a specific user in a downlink.

The downlink subframe starts with a preamble used for synchronization and equalization in the physical layer, and then a downlink MAP of a broadcast type defining the location and use of bursts allocated to the downlink and uplink. The structure of the entire frame is defined through a (DL-MAP) message and an uplink MAP (UL-MAP) message.

The DL-MAP message defines the usage allocated per burst for the downlink interval in the burst mode physical layer, and the UL-MAP message defines the usage of the burst allocated for the uplink interval. Information element (IE) constituting DL-MAP is based on Downlink Interval Usage Code (DIUC), Connection ID (CID), and location information (subchannel offset, symbol offset, number of subchannels, number of symbols) of burst. Downlink traffic intervals are divided at the user end. On the other hand, the information elements constituting the UL-MAP message is determined by the Uplink Interval Usage Code (UIUC) for each CID (Connection ID), the location of the interval is defined by the 'duration'. Here, the use of each section is determined according to the UIUC value used in the UL-MAP, and each section starts at a point separated from the previous IE starting point by the 'duration' defined in the UL-MAP IE.

Downlink Channel Descriptor (DCD) messages and Uplink Channel Descriptor (UCD) messages are physical layer-related parameters to be applied in burst periods allocated to downlink and uplink, respectively, such as modulation type and FEC code type. It includes. In addition, it defines the necessary parameters (for example, K, R values of the R-S Code, etc.) according to various types of forward error correction codes. Such parameters are given by a burst profile defined for each Uplink Interval Usage Code (UIUC) and Downlink Interval Usage Code (DIUC) in UCD and DCD, respectively.

Meanwhile, multi-input multi-output (MIMO) technology of an OFDM / OFDMA system is classified into a diversity series and a multiplexing series. The diversity scheme combines signals that have undergone different Rayleigh fading for each antenna by a plurality of transmit / receive antennas, thereby improving reception performance by compensating channel deeps between paths. The diversity gain obtained by this technique is further divided into transmit diversity and receive diversity depending on whether it is obtained at the transmitter or the receiver. If the number of transmit antennas is N and there are M receive antennas, the maximum diversity gain is MN because up to MN independent fading channels can be combined.

In the multiplexing method, a virtual subchannel between transmit and receive antennas is created to transmit different data through each transmit antenna to increase transmission speed. Unlike the diversity method, the multiplexing method cannot sufficiently obtain the gain when multiple antennas are used only at the transmitter or the receiver side. The performance of the multiplexing scheme is expressed by the multiplexing gain of the number of independent transmission signals that can be transmitted simultaneously, which is equal to the minimum of the number of antennas at the transmitting end and the number of antennas at the receiving end.

In addition, there is a Collaborative Spatial Multiplexing (CSM) method as a type of multiplexing method. The CSM method is a technology that allows two UEs to use the same uplink, thereby saving uplink radio resources.

In an OFDM / OFDMA system, uplink or downlink radio resources, that is, data burst allocation schemes, are classified into general MAP schemes and HARQ schemes according to whether or not the HARQ scheme is supported.

In downlink, the burst allocation method in general MAP teaches a rectangular shape consisting of a time axis and a frequency axis. That is, it teaches the start symbol number (symbol offset), the start subchannel number (subchannel offset), the number of symbols used and the number of subchannels (No. OFDMA symbols, No. Subchannels) used. Uplink uses a method of assigning the symbol axis in sequence so that the burst of uplink can be allocated by only teaching the number of symbols used.

4 is a view for explaining the operation of the prior art of allocating an uplink radio resource (data burst) to the terminal using a common DL-MAP.

In the case of a typical DL-MAP, the position of the UL-MAP allocates the first burst immediately following. In the UL-MAP scheme, an uplink data burst is allocated through the UL-MAP IE.

In the OFDMA technology of IEEE 802.16d, e, the CSM method is a general DL-MAP method. A base station transmits a location of a data burst to each terminal through a MIMO UL basic IE having a data format as shown in Table 1. Allocates the same uplink resource.

In order to inform the use of the MIMO UL basic IE, an extended UIUC is used with a value of UIUC = 15. There are a total of 16 IEs that can be expressed with this extended UIUC.

Syntax Size (bits) Notes MIMO_UL_Basic_IE () {   Extended DIUC 4 MIMO = 0x02   Length 4 Length of the message in bytes (variable)   Num_assign 4 Number of burst assignment   For (j = 0; j <Num_assign; j ++) {     CID 16 SS basic CID     UIUC 4     MIMO_Control One For dual transmission capable MSS 0: STTD 1: SM For Collaborative SM capable MSS 0: pilot pattern A 1: pilot pattern B     Duration 10 In OFDMA slots   } }

The MIMO UL Basic IE used for allocating the same uplink resource to two terminals is also used for other existing MIMO. First, in case of a terminal having two or more antennas, it informs whether the STTD method for obtaining diversity gain or the SM method for increasing the transmission speed.

In the OFDMA technology of IEEE 802.16d, e, it will be apparent to those skilled in the art that the CSM scheme may also be implemented through HARQ MAP for HARQ implementation.

The prior art as described above causes a problem when the use of uplink is increased and thus requires more radio resources. If more radio resources are needed due to an increase in uplink usage, we can consider adding a frequency resource.However, in this case, since the location of the base station needs to be considered and affects the entire system, the uplink usage is increased. It is not seen as a preferred alternative to the increase.

The present invention has been made to solve the problems of the prior art as described above, an object of the present invention, the radio resources of OFDM / OFDMA to allow multiple users to occupy one radio resource allocated in the uplink at the same time To provide an allocation method.

Summary of the Invention

In order to achieve the above object, the radio resource allocation system according to the present invention is characterized in that in the orthogonal frequency division multiple access system, the radio resources of the same uplink is allocated to two or more terminals.

In order to achieve the above object, the data transmission and reception method according to the present invention, while receiving a data signal using a plurality of sub-carriers from a plurality of transmitting side to which the same radio resources are allocated, to distinguish the plurality of transmitting side Receiving a data signal including a pilot signal according to a pilot pattern; And acquiring a data signal of each terminal by identifying the data signal of each terminal from the received data signal through the pilot signal, wherein the plurality of transmitting sides are spatial multiplexed in a specific time interval. Spatial Multiplexing (Spatial Multiplexing) method for transmitting the data signal, in the remaining time interval, some of the plurality of transmitting side transmits the same data signal, and the other transmitting side transmits the signal by changing the phase of the data signal do.

In another aspect of the present invention, the data transmission and reception method according to the present invention, in a communication system including a plurality of transmitting side, the data signal is transmitted through the same radio resources allocated to each of the plurality of transmitting side, And transmitting a data signal including a pilot signal according to a pilot pattern for distinguishing the plurality of transmitters, wherein the plurality of transmitters transmit signals in a spatial multiplexing scheme, Transmitting a specific data signal in a time interval, some of the plurality of transmitting side transmits the specific data signal in the remaining time interval, and the other transmitting side transmits the signal by changing the phase of the specific data signal .

One embodiment of the invention

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. One embodiment of the present invention is a technique for increasing the capacity of the uplink, and the object of the present invention is to allow a plurality of users to simultaneously use the radio resources allocated to one user.

FIG. 5 is a diagram illustrating allocation of uplink radio resources in an OFDM / OFDMA system according to the present invention. For convenience of explanation, it is assumed that user 1 and user 5 are allocated the same radio resource.

The communication system first informs the two users (user 1 & user 5) that the same radio resources are allocated to each other through signaling or a message, and indicates the type of channel coding to be used, the coding rate, the modulation method, the pilot pattern, and the space-time code method. Give information.

Signal transmission between the terminal of the two users (User 1 & User 5) and the communication system has different combinations of transmission and reception according to the space-time code method, the number of reception antennas of the base station, and the number of transmission antennas of the terminal. The following describes five different combinations of transmit and receive.

First, in the case of a spatial multiplexing transmission scheme, when the terminals of the two users (User 1 & User 5) each have one transmitting antenna, and the base station has two or more receiving antennas, a combination of transmission and reception is defined. It is as shown in Equation 1 below.

In Equation 1, x _i is a signal received at the i th antenna of the base station, h _ji is a channel transmitted from the i th terminal to the j th antenna of the base station, s _i is data of the i th terminal, ν Is an Additive White Gaussian Noise Vector (AWGN Vector).

Second, under the spatial multiplexing transmission method, when the terminals of the two users (user 1 & user 5) each have one transmitting antenna and the base station has one receiving antenna, the combination of transmission and reception is defined by Equation 2 below. Same as

In Equation 2, x is a signal received at the base station, h _i is a channel transmitted from the i-th terminal to the base station, s _i is the data of the i-th terminal, ν is an additional white Gaussian noise vector (Additive White Gaussian Noise Vector, AWGN Vector).

Third, under the Space Time Transmit Diversity transmission scheme, each of two UEs (User 1 & User 5) has two transmit antennas, and the base station has two or more receive antennas. In this case, the combination of transmission and reception is defined as in Equation 3 below.

In Equation 3, x _i is a signal received at the i-th antenna of the base station, h _{i, jm} is a channel transmitted from the m-th antenna of the i-th terminal to the j-th antenna of the base station, s _{i , j} is the j-th data of the i-th terminal, v is an Additive White Gaussian Noise Vector (AWGN Vector).

Fourth, in the case of a spatial multiplexing transmission method, when the terminals of the two users (user 1 & user 5) each have a plurality of transmission antennas, and the base station has four or more reception antennas, the combination of transmission and reception is defined. Same as 4.

In Equation 4, x _i is a signal received at the i-th antenna of the base station, h _{i, jk} is a channel transmitted from the k-th antenna of the i-th terminal to the j-th antenna of the base station, s _{i , j} is the j-th data of the i-th terminal, v is an Additive White Gaussian Noise Vector (AWGN Vector).

Fifth, in the case of a spatial multiplexing transmission method, when the terminals of the two users (user 1 & user 5) each have one transmitting antenna and the base station has one or more receiving antennas, the equation If a combination that is transmitted and received using a B-type transmission matrix (form B in Equation 5) different from the A-type transmission matrix used in Equation 5 is defined as Equation 6 below:

In Equation 6, x _i is a signal received by the i-th antenna of the base station, k represents a time interval, h _{i, j} is a channel transmitted from the antenna of the j-th terminal to the i-th antenna of the base station, s _i is data of the i-th terminal, and v is an Additive White Gaussian Noise Vector (AGWN Vector).

6 is a diagram illustrating a transmission scheme according to an embodiment of the present invention. According to FIG. 6, the transmitting side transmits data in two time intervals. That is, in the fifth transmission method, after dividing data into two time intervals by using a spatial multiplexing transmission method in the uplink, it is assumed that there is no channel change in each time interval, and the equation for the two time intervals The present invention relates to a method of transmitting data using a B-type transmission matrix. As shown in FIG. 6, the terminal 1 (user 1 or user 5) and the terminal 2 (user 1 or user 5) transmit data of s ₁ (data1) and s ₂ (data2), respectively, during a T time period. During the T + 1 time interval, data is transmitted in the form of data of s ₁ (data1) and -s ₂ (-data2) having orthogonality to the T time interval. For example, when the terminal 1 is designated as the first user (user 1) and the terminal 2 is designated as the second user (user 5), the first user transmits data of s ₁ (data1) during the T time interval. In addition, during the T + 1 time interval, the data of s ₁ (data1) is transmitted, and the second user transmits the data of s ₂ (data2) during the T time interval, and -s ₂ (- Send data of data2). As a result, the data signal transmitted by the first user during the T time and T + 1 time intervals is orthogonal to the data signal transmitted by the second user during the T time and T + 1 time intervals. As shown, data signals transmitted through the terminal 1 and the terminal 2 are transmitted together with the pilot signal, and the pilot signal is transmitted according to a specific pilot pattern. The pilot pattern will be described with reference to FIG. 7.

Using the fifth transmission method described above, the data rate is reduced by half because data can be sent repeatedly, but it can compensate for the low performance in a low SNR environment. This maintains the advantage of ease of decoupling of the signal. Decoupling means separating and detecting a signal. According to the fifth transmission method described above, channel inversion is easy and there is an advantage of simplifying channel estimation.

According to an embodiment of the present invention, when the base station determines the transmission and reception combination of the terminal and the base station, according to the state of the channel whether to transmit using the transmission matrix of the type A in Equation 5 or B type proposed in the present invention It is more desirable to determine whether to use a transmission matrix of. That is, the base station can determine the combination of transmission and reception of the terminal and the base station by a communication environment such as a channel environment. The type of a method for notifying a transmission / reception combination of the terminal and the base station is not limited, and the transmission / reception combination may be notified through a message generated from a higher layer or a message generated in a physical layer.

The communication system transmits predetermined information (information such as channel coding type, coding rate, modulation method, pilot pattern, space-time code method, etc.) to the two users (User 1 & User 5), according to a predetermined criterion ( Alternatively, the two users (User 1 & User 5) can be ranked (assuming that User 1 is the first user and User 5 is the second user).

FIG. 7 is a diagram illustrating a basic allocation unit of radio resources transmitted through uplink of an OFDM / OFDMA system, and a multiple of the basic allocation unit becomes a minimum allocation unit that can be allocated to one user. In the existing example, six times the basic allocation unit is the minimum allocation unit.

The frequency axis of the basic allocation unit may be a sub-carrier order, or a group unit axis may be configured by grouping a plurality of sub-carriers (or adjacent) that are scattered (or adjacent). The order of configuring the axes may have any order.

The basic allocation unit transmitted through the uplink of the OFDM / OFDMA system may have a structure and size different from those of FIG. 7 according to the characteristics of the system, and the arrangement of pilots and data may also be different. If a basic allocation unit different from that of FIG. 7 is used, pilot patterns corresponding thereto can be combined as shown in FIG. 9.

The communication system analyzes the pilot pattern of the basic allocation unit received through the uplink to distinguish which user the received data is. That is, the pattern of the pilot included in the basic allocation unit is analyzed to determine whether the received data is user 1 or user 5.

8A and 8B are diagrams illustrating patterns of pilots according to an embodiment of the present invention, and FIG. 8C is a table showing signal values allocated to each pilot of FIGS. 8A and 8B.

Patterns 1, 2, and 3 shown in FIG. 8A allow users 1 and 5 to use different pilots to identify data of two users. Pattern 4 of FIG. 8B shows that user 1 and user 5 The same pilot subcarrier is used, but data identification is performed using a code that can be distinguished from each other, for example, an orthogonal code.

In detail, the pattern 1 is a pilot based on time division and frequency division, the pattern 2 is a pilot based on frequency division, the pattern 3 is a pilot based on time division, and the pattern 4 is code division. According to the pilot.

8A and 8B illustrate an example according to the present invention, the shape of which may vary depending on a basic allocation unit. In addition, if the radio resources of the two users (user 1 and user 5) are composed of a plurality of basic allocation units, as shown in FIG. 9, the patterns of FIGS. 8A to 8C may be combined.

Since the pilot is used to compensate for the distortion caused by the radio channel, the first user pilot and the second user pilot should alternately appear. The base station uses the pilot signal for radio channel measurement and channel correction of each user, and applies to a method of classifying data of users. The data of each user is separated / detected by applying the number of concurrently allocated users and the wireless channel of each user to a formula of a detection method such as Maximum likelihood.

Hereinafter, further preferred embodiments according to the present invention will be described.

In the case of a terminal capable of Collaborative Spatial Multiplexing (CSM), allocating resources of the same uplink to the two terminals and using different pilot patterns in order to distinguish signals from the two terminals. It is possible to apply the CSM method to two terminals having two antennas through general DL-MAP and HARQ MAP.

10 is a view for explaining the operation of the CSM method using a general DL-MAP according to an embodiment of the present invention.

In the general DL-MAP, the UL-MAP allocates the first data burst immediately following the UE. The UL-MAP allocates a data burst as shown in FIG. 10 through the UL-MAP IE.

In the case of the CSM scheme, the positions of the bursts allocated to the two terminals are informed by the MIMO UL Enhanced IE having the format shown in Table 3 or the existing MIMO UL Basic IE.

Hereinafter, a description will be given of an implementation example of a CSM method using a new IE, which is a MIMO UL Enhanced IE. When all IEs that can be represented by UIUC are filled, as shown in Table 2, a new extended UIUC can be newly created in 11 slots for adding a new IE.

UIUC Usage 0 Fast-Feedback Channel 1-10 Different burst Profiles 11 New extended UIUC 12 CDMA Bandwidth Request, CDMA ranging 13 PARP reduction allocation, Safty zone 14 CDMA Allocation IE 15 Extended UIUC

Syntax Size (bits) Notes MIMO_UL_Enhanced_IE () {   New extended UIUC 4 Enhanced MIMO = 0x01   Length 4 Length of the message in bytes (variable)   Num_assign 4 Number of burst assignment For (j = 0; j <Num_assign; j ++) {   Num_CID 2   For (i = 0; i <Num_CID; i ++) {     CID 16 SS basic CID     UIUC 4     MIMO control 2 For dual transmission capable MSS 00: STTD / pilot pattern A, B 01: STTD / pilot pattern C, D 10: SM / pilot pattern A, B 11: SM / pilot pattern C, D For Collaborative SM capable MSS with one antenna. 00: pilot pattern A 01: pilot pattern B 10-11: reserved   }   Duration 10 In OFDMA slots } Padding variable }

The contents of Table 3 are as follows.

Uplink resource allocation is determined by a field value of 'duration'. Unlike the rectangular resource allocation used in the downlink, the terminal accumulates the number of slots allocated on the time axis and informs the terminal. In this case, the number of bursts to be used is informed by the 'Num_assign' field, and the CIDs (connection IDs) of the terminal allocated to each burst are repeatedly reported.

The characteristic of the burst assigned to the terminal is determined by the 'MIMO control' field. For Collaborative Spatial Multiplexing (CSM), one of the MIMO modes, the UE registers with the base station and negotiates with each other whether CSM is possible, and applies CSM to the CSM-capable UE. Table 4 illustrates the structure of an SBC Request / Response (REQ / RSP) message exchanged during CSM negotiation between the base station and the terminal.

Type Length Value Xxx 1 bit Bit # 0: Collaborative SM Bit # 1-7: reserved

In the case of two terminals having one antenna, the base station distinguishes the two signals by different pilot patterns A and B. In the case of terminals having two antennas, a pilot pattern A and B are assigned to one terminal, and pilot patterns C and D are assigned to another terminal.

As mentioned above, newly added IEs, such as MIMO UL Enhanced IE, are available through Extended UIUC = 11. The MIMO UL Enhanced IE may be used when the terminal has one antenna as well as when the terminal has two antennas. The feature of the IE is that two terminals are simultaneously allocated to one uplink burst sent to the base station. As shown in FIG. 10, an uplink burst (burst # 1, burst # 2) allocated to two terminals is allocated using one uplink.

The following describes an embodiment of implementing the CSM method using the existing IE MIMO UL Basic IE. Table 5 shows the data format of the MIMO UL basic IE.

Syntax Size (bits) Notes MIMO_UL_basic_IE () {   Extended UIUC 4 MIMO = 0x02   Length 4 Length of the message in bytes (variable)   Num_assign 4 Number of burst assignment For (j = 0; j <Num_assign; j ++) {     CID 16 SS basic CID     UIUC 4     MIMO control 2 For dual transmission capable MSS 0: STTD 1: SM For Collaborative SM capable MSS 0: pilot pattern A 1: pilot pattern B   Duration 10 In OFDMA slots   Pilot pattern One For Collaborative SM dual transmission capable MSS 0: pilot pattern A B 1: pilot pattern C D } Padding variable }

The MIMO UL Basic IE used by the base station to allocate the same uplink resource (data burst) to two terminals is also used for other existing MIMO. First, in case of a terminal having two or more antennas, it is informed whether to use the STTD method for obtaining diversity gain or the SM method for increasing the transmission rate in the 'MIMO control' field. In addition, in case of a terminal supporting the CSM scheme, the same uplink resource is allocated to the two terminals through the 'MIMO control' field, and the different pilot patterns are used to distinguish the signals transmitted from the two terminals. . For the application of the present invention, the existing 'MIMO control' field indicates a pilot pattern to be used by two terminals using one bit reserved for CSM only when it has two antennas. Pilot patterns range from A to D and assign two to each terminal.

As will be apparent to those skilled in the art that the embodiment of the present invention may be implemented through HARQ MAP instead of the general DL-MAP, the operation of the CSM method through HARQ MAP is also possible.

It is apparent to those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit and essential features of the present invention. Accordingly, the above detailed description should not be construed as limited in every respect and should be considered as illustrative. The scope of the invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the invention are included in the scope of the invention.

As described above, the present invention implements a method in which two or more users simultaneously use radio resources allocated to one user, thereby increasing capacity of uplink without adding a frequency band. In addition, the present invention allows the TDD scheme to allocate the radio resources that had to be allocated to the uplink, such that some of the time allocated to the uplink is allocated to the downlink, thereby efficiently managing the limited radio resources. It became.

Claims (9)

Receive a data signal using a plurality of subcarriers from a plurality of transmitters to which the same radio resource is allocated, Receiving a data signal including a pilot signal according to a pilot pattern for identifying the plurality of transmitting sides; And Identifying a data signal of each terminal from the received data signal through the pilot signal to obtain a data signal of each terminal; Including but not limited to The multiple transmitters transmit the data signal in a spatial multiplexing scheme in a specific time interval. During the remaining time intervals, some of the plurality of transmitting sides transmit the same data signal, and the other transmitting side changes the phase of the data signal to transmit the signal. Method for transmitting and receiving data using a plurality of subcarriers characterized in that. The method of claim 1, Receiving an additional data signal including a pilot signal according to a pilot pattern for identifying the plurality of transmitting sides; The multiple transmitters are configured to transmit the additional data signal in a spatial multiplexing scheme. Method for transmitting and receiving data using a plurality of subcarriers characterized in that. The method of claim 2, The plurality of transmitters are configured to transmit the additional data signal in a spatial multiplexing scheme when receiving the indication information indicating a spatial multiplexing scheme from a receiver. Method for transmitting and receiving data using a plurality of subcarriers characterized in that. The method of claim 1, The pilot pattern is classified according to a time interval in which the pilot signal is transmitted. Method for transmitting and receiving data using a plurality of subcarriers characterized in that. The method of claim 1, The pilot pattern is classified according to the frequency domain over which the pilot signal is transmitted. Method for transmitting and receiving data using a plurality of subcarriers characterized in that. The method of claim 1, The pilot pattern is classified according to a time interval and a frequency domain in which the pilot signal is transmitted. Method for transmitting and receiving data using a plurality of subcarriers characterized in that. The method of claim 1, The pilot pattern is distinguished by a code applied to the pilot signal. Method for transmitting and receiving data using a plurality of subcarriers characterized in that. The method of claim 1, The pilot pattern is distinguished by a code applied to the pilot signal. Method for transmitting and receiving data using a plurality of subcarriers characterized in that. In a communication system comprising a plurality of transmitting sides, While transmitting data signals through the same radio resources allocated to the plurality of transmitters, And transmitting a data signal including a pilot signal according to a pilot pattern for identifying the plurality of transmitting sides. The multiple transmitters transmit signals in a spatial multiplexing scheme, Transmit a specific data signal in a specific time interval, During the remaining time intervals, some of the plurality of transmitting sides transmit the specific data signal, and the other transmitting side changes the phase of the specific data signal to transmit the signal. Method for transmitting and receiving data using a plurality of subcarriers characterized in that.

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