KR20180005375A - Terminal device and reference signal transmitting method - Google Patents

Abstract

The present invention relates to a MIMO system using a beam-forming technology. Disclosed are a terminal device and a reference signal transmitting method which can provide an environment capable of obtaining a channel state of a downlink channel with respect to the maximum number of terminals by using the same wireless resources in obtaining the channel state of the downlink channel with respect to the terminals.

Description

TECHNICAL FIELD [0001] The present invention relates to a terminal device and a reference signal transmission method,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a MIMO system using a beamforming technique, and more particularly, to a MIMO system using a beamforming technique, The present invention relates to a technique for providing an environment capable of grasping a channel state of a channel.

In recent years, by performing communication based on beamforming technology on the premise that the number of antennas of a transmitting apparatus and the number of antennas of a receiving apparatus are provided, A variety of techniques have been developed that can expect a transmission capacity gain, and MIMO (Multiple Input Multiple Output) technology is a typical technique.

The greatest part of obtaining a transmission capacity gain in a communication system of a MIMO technology (hereinafter referred to as a MIMO system) is a diversity gain and a multiplexing gain through beamforming.

For this purpose, beamforming techniques used in MIMO systems are divided into analog beamforming, digital beamforming, and hybrid beamforming. In the MIMO system, the hybrid beamforming technique combining the two beamforming techniques is mainly used because of the disadvantages of the digital beamforming technique in which the RF chain is required for the number of antennas and the installation cost is increased and the analog beamforming technique in which the performance gain is limited .

Among the transmitting / receiving apparatuses such as the base station and the terminals communicating based on the beam forming technique, the channel states of the downlink channels among the antenna beams in various directions that can be formed by the transmitting apparatus and the antenna beams in various directions that can be formed by the receiving apparatus An optimal beamforming gain can be expected only by performing beamforming (hereinafter referred to as optimal beamforming) through an antenna beam pair (transmitting apparatus / receiving apparatus) forming an excellent downlink channel.

Therefore, in the MIMO system using the beamforming technique, it is essential to grasp the channel state of the downlink channel for the UE in order to perform the optimal beamforming. In the prior art, after the UE measures the channel condition of the downlink channel When the information on the measured channel state is reported (feedback) to the base station, the base station can obtain the feedback information and grasp the channel status of the downlink channel to the terminal.

However, as the number of antennas increases in the MIMO system, the number of downlink channels to be measured by the UE increases and the amount of information to be fed back to the base station increases, so that the uplink radio resource for the UE to transmit actual data is insufficient Lt; / RTI >

However, in the MIMO system using the beam-forming technique up to now, no concrete method for solving the aforementioned problem has been proposed.

Accordingly, in the present invention, a specific method for solving the above-mentioned problem in detecting the channel state of the downlink channel for the terminal is proposed.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a MIMO system using a beamforming technique, And to provide an environment in which the status can be grasped.

According to a first aspect of the present invention, there is provided a terminal apparatus comprising: a resource unit for recognizing a radio resource variable-allocated from a base station for transmission of a reference signal; And a reference signal transmission unit for transmitting a reference signal to the base station in a multi-user-multiple input / output (MU-MIMO) scheme in the radio resource to increase the number of terminals capable of transmitting a reference signal in the same radio resource .

Preferably, the reference signal transmitter may transmit a reference signal of each uplink channel according to a plurality of antenna beams that are beamformed in different directions in the radio resource to the base station in an MU-MIMO scheme.

Preferably, the BS processes the reference signals of the uplink channels according to the MU-MIMO scheme to distinguish the terminal devices as the transmission subjects, It is possible to grasp the channel state of the downlink channel for the terminal apparatus based on the channel state of the uplink channel and to perform the optimal beamforming.

Advantageously, the reference signal may be a Sounding Reference Signal (SRS).

Preferably, the reference signal transmitting unit transmits the reference signal of the MU-MIMO scheme by the base station when the number of UEs attempting to transmit a reference signal in the radio resource is greater than or equal to a specific number that can be received when the MU- If it is designated, the reference signal can be transmitted in the MU-MIMO scheme.

According to a second aspect of the present invention, there is provided a method of transmitting a reference signal by a terminal, the method comprising: recognizing a radio resource variable-allocated from a base station to transmit a reference signal; And a reference signal transmission step of transmitting a reference signal to the base station in a multi-user-multiple input / output (MU-MIMO) scheme in the radio resource, thereby increasing the number of terminals capable of transmitting a reference signal in the same radio resource .

Preferably, the reference signal transmission step may transmit a reference signal of each uplink channel according to a plurality of antenna beams that are beamformed in different directions in the radio resource to the base station in an MU-MIMO scheme.

Preferably, the BS processes the reference signals of the uplink channels according to the MU-MIMO scheme to distinguish the terminal devices as the transmission subjects, It is possible to grasp the channel state of the downlink channel for the terminal apparatus based on the channel state of the uplink channel and to perform the optimal beamforming.

Preferably, the reference signal transmission step includes: when the number of UEs attempting to transmit a reference signal in the radio resource is greater than or equal to a specific number that can be accommodated when the MU-MIMO scheme is not used, or when the reference signal transmission of the MU- A reference signal can be transmitted in the MU-MIMO scheme.

Therefore, according to the terminal device and the reference signal transmission method of the present invention, it is possible to grasp the channel state of the downlink channel for the maximum number of terminals using the same radio resource in the MIMO system using the beam forming technique .

Therefore, according to the present invention, optimal beamforming can be performed for a maximum number of UEs using a minimum amount of uplink radio resources, so that the effect of improving beamforming performance can be expected.

1 is an exemplary diagram illustrating a MIMO system to which the present invention is applied.
2 is an illustration showing a configuration of a terminal device according to a preferred embodiment of the present invention.
FIG. 3 is an exemplary diagram illustrating variable allocation of radio resources for SRS according to a preferred embodiment of the present invention.
4 is an exemplary diagram illustrating a flow of a reference signal transmission method according to a preferred embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

1 is an exemplary diagram showing a MIMO system using a beamforming technique to which the present invention is applied.

The MIMO (Multiple Input Multiple Output) technique is a technique that can expect a transmission capacity gain proportional to the number of transmission antennas and the number of reception antennas even if no additional frequency or power is used. And a diversity gain and a multiplexing gain.

For this purpose, beamforming techniques used in MIMO systems are divided into digital beamforming, analog beamforming, and hybrid beamforming.

In the case of digital beamforming, the number of beams that can be formed is determined by the number of RF chains, and a plurality of beams formed by digital beamforming improves the diversity of the receiving end to improve the signal to interference ratio (SINR) ), And can also be used for multiplexing to separate multiple receivers into different beams, each receiving a different signal.

On the other hand, in the case of the analog beamforming, a plurality of beams formed by the analog beamforming can be used only as means for improving the diversity of the receiving end and increasing the signal quality (SINR).

As a result, in the MIMO system, due to the disadvantages of the digital beamforming technique in which an RF chain is required for the number of antennas and the installation cost is increased and the analog beamforming technique in which the performance gain is limited, the hybrid beam Foaming technology is mainly used.

Hereinafter, the present invention will be described with reference to a hybrid beam forming technique.

As shown in FIG. 1, in a MIMO system using a beamforming technique such as a hybrid beamforming technique to which the present invention is applied, a transmission / reception device communicating based on a beamforming technique, such as a base station and a terminal, (Hereinafter referred to as " optimal beam forming ") through an antenna beam pair (transmitting apparatus / receiving apparatus) constituting a downlink channel having the best channel state of the downlink channel among the antenna beams in various directions, Beamforming), it is possible to expect an optimal beamforming gain.

Therefore, in the MIMO system using the beamforming technique, it is essential to grasp the channel state of the downlink channel for the UE in order to perform the optimal beamforming. In the prior art, after the UE measures the channel condition of the downlink channel When the information on the measured channel state is reported (feedback) to the base station, the base station can obtain the feedback information and grasp the channel status of the downlink channel to the terminal.

However, as the number of antennas increases in the MIMO system, the number of downlink channels to be measured by the UE increases and the amount of information to be fed back to the base station increases, so that the uplink radio resource for the UE to transmit actual data is insufficient Lt; / RTI >

However, in the MIMO system using the beam-forming technique up to now, no concrete method for solving the aforementioned problem has been proposed.

Accordingly, in the present invention, a concrete method for solving the above-mentioned problem in analyzing the channel state of the downlink channel for the UE in order to perform optimal beamforming is proposed.

Specifically, an attempt is made to provide an environment capable of grasping a channel state of a downlink channel for a maximum number of terminals using the same radio resource.

Referring to FIG. 1, in the MIMO system, the base station 10 basically includes a plurality of antennas, and the terminals 1, 2,... Also include a plurality of antennas.

Hereinafter, for convenience of explanation, it is assumed that the base station 10 has eight antennas, and the terminals 1, 2, ... have four antennas.

In the MIMO system to which the present invention is applied, TDD (Time Division Duplex) in which the same frequency radio resource is allocated to UL or DL according to time is used, and in particular, UL / It is assumed that Dynamic TDD capable of adapting to DL traffic is adopted.

In addition, in the MIMO system to which the present invention is applied, the base station 10 includes a multi-user multiple input multiple output (MIMO) system capable of providing communication services to multiple users through the same radio resource (frequency / time) .

Therefore, it is assumed that the terminals 1, 2, ... in the MIMO system to which the present invention is applied can also use the communication service through the MU-MIMO scheme.

Under the assumption as described above, in the present invention, the base station 10 variably allocates radio resources that enable a terminal to transmit a reference signal.

Here, the reference signal is preferably a sounding reference signal (SRS).

That is, the base station 10 variably allocates a radio resource (hereinafter, referred to as an uplink SRS radio resource) that enables a terminal to transmit a reference signal, that is, an SRS.

At this time, the manner in which the base station 10 variably allocates the uplink SRS radio resources is in accordance with the adopted dynamic TDD allocation policy, and the allocation policy of the dynamic TDD may be one of various ones used conventionally. I will omit.

However, for example, as shown in FIG. 3, the base station 10 can variably allocate the uplink SRS radio resource (a) in the PUSCH (Physical Uplink Shared CHannel) in the subframe-based radio resource . Then, the base station 10 may provide information for identifying / recognizing allocation of uplink SRS radio resource (a) through a physical downlink control channel (PDCCH).

In the meantime, it has been assumed that the MIMO system to which the present invention is applied adopts Dynamic TDD. Therefore, since the frequency radio resource used for UL can be used for DL and the frequency radio resource used for DL can be used for UL, when the channel state of the frequency radio resource (uplink channel) used for UL is used as DL It can be regarded as a downlink channel channel state of the uplink channel.

Therefore, in the present invention, a new method using the above-mentioned Dynamic TDD feature (reciprocity) is proposed instead of the existing method of reporting (feedback) the channel state of the downlink channel measured by the terminal to the base station.

That is, in the present invention, the BS measures the channel state of the uplink channel for the UE through the SRS transmitted by the UE in the uplink, and regards the channel state of the uplink channel as the channel state of the downlink channel, It is desired to grasp the channel state of the downlink channel for the UE.

In the present invention, terminals (1, 2, ...) recognize radio resources that are variable allocated from the base station 10, that is, uplink SRS radio resources for SRS transmission.

For example, the terminals 1, 2 ... can recognize the uplink SRS radio resource (a) variably allocated from the base station 10 for SRS transmission through the information provided via the PDCCH.

Then, the terminals 1, 2, ... transmit the SRS to the base station 10 in the MU-MIMO manner in the uplink SRS radio resource (a) recognized and transmit the SRS to the base station 10 So that the limit number can be increased.

That is, in the present invention, when the SRS is transmitted from the uplink SRS radio resource (a) to the base station 10 in the MU-MIMO scheme, the terminals 1, 2, ), The number of terminals that can transmit SRS can be increased to the number that can be accommodated by the MU-MIMO scheme.

In this case, a maximum number of terminals can transmit SRS using the same radio resource or uplink SRS radio resource (a), which means that the base station 10 can transmit downlink The channel state of the channel (<= channel state estimation of the uplink channel) can be grasped.

Hereinafter, a terminal device 100 according to a preferred embodiment of the present invention will be described in more detail with reference to FIG. The terminal device 100 of the present invention corresponds to the terminals 1, 2, ... shown in Fig.

The terminal apparatus 100 according to the present invention includes a resource unit 110 for recognizing a radio resource that is variably allocated from the base station 10 for reference signal transmission and a resource unit 110 for receiving a multiuser multi- And a reference signal transmitter 120 for transmitting a reference signal to the base station 10 and increasing the number of terminals that can transmit a reference signal in the same radio resource.

The resource hold unit 110 recognizes radio resources that are variably allocated from the base station 10 for reference signal transmission.

More specifically, the resource hold unit 110 recognizes a reference signal, that is, a radio resource that is variable-allocated from the base station 10, that is, an uplink SRS radio resource for SRS transmission.

For example, the resource hold unit 110 can recognize the uplink SRS radio resource (a) variably allocated from the base station 10 through the information provided on the PDCCH.

The reference signal transmitting unit 120 transmits the SRS to the base station 10 in the MU-MIMO manner in the recognized radio resource, that is, the uplink SRS radio resource (a) Thereby increasing the number.

More specifically, the reference signal transmitting unit 120 transmits SRS of each uplink channel according to a plurality of antenna beams that are beamformed in different directions in a radio resource (i.e., uplink SRS radio resource (a)) to MU-MIMO To the base station 10. [

For example, assuming that the terminal apparatus 100 includes four antennas as described above, the reference signal transmitting unit 120 transmits the uplink SRS radio resource (a) through four antennas in different directions And the SRS of each uplink channel according to the beamformed four antenna beams is transmitted to the base station 10 by the MU-MIMO scheme.

Of course, when the uplink SRS radio resource a is composed of a plurality of symbols (e.g., 14), the four antenna beams that beamform in different directions through the four antennas in the terminal apparatus 100, May differ for each symbol in the SRS radio resource (a).

In this case, the reference signal transmitting unit 120 transmits the SRS of each uplink channel (4 * 14) according to the four antenna beams formed for each symbol in the uplink SRS radio resource (a) to the MU-MIMO To the base station 10 in the same manner.

Hereinafter, for convenience of description, a process of transmitting SRS of 4 uplink channels by MU-MIMO scheme on the basis of a single symbol in uplink SRS radio resource (a) will be described.

In order to perform MU-MIMO communication, the base station 10 recognizes a precoding matrix generated for each of the terminals 1, 2, ..., and each of the terminals 1, 2, And recognizes the generated precoding matrix.

At this time, an algorithm in which a precoding matrix is generated for each of the terminals 1, 2, ..., and a process in which the base station 10 and the terminals 1, 2, The present invention can be adopted in the algorithms and the processes proposed in the related art, and a detailed description thereof will be omitted.

The reference signal transmitting unit 120 transmits the reference signal to the SRS in four uplink channels corresponding to a plurality of antenna beams, for example, four antenna beams, which are beamformed in different directions using the uplink SRS radio resource (a) (SRS * precoding matrix) in the MU-MIMO scheme by multiplying the precoding matrix of the device 100 by the precoding matrix of the device 100 and transmitting the result to the base station 10.

Meanwhile, when the number of UEs attempting to transmit SRS in the uplink SRS radio resource (a) is greater than or equal to a specific number that can be accommodated when the MU-MIMO scheme is not used, the reference signal transmitter 120 may transmit the SRS using the MU- SRS can be transmitted.

That is, when the number of terminals attempting SRS transmission is small in the uplink SRS radio resource (a) variably allocated by the base station 10, it is not necessary to transmit the SRS in the MU-MIMO scheme as described above, The SRS 120 may transmit the SRS using an existing method that does not apply the MU-MIMO scheme, for example, a Frequency Division Multiplexing (FDM) scheme or a CDM (Code Division Multiplexing) scheme.

However, if the number of terminals attempting to transmit SRS in the uplink SRS radio resource (a) is greater than or equal to a specific number that can be accommodated in the conventional scheme, for example, the FDM scheme or the CDM scheme, the reference signal transmission unit 120 transmits It is preferable to transmit the SRS in the MU-MIMO scheme.

For example, if the base station 10 recognizes that the number of terminals attempting to transmit SRS in the uplink SRS radio resource (a) is greater than or equal to a specific number that can be accommodated in the conventional manner, such as FDM or CDM, It is possible to notify all of the terminals 1, 2 ... in the MU-MIMO system so that the terminals 1, 2 ... can transmit the SRS in the MU-MIMO manner.

Alternatively, if the base station 10 recognizes that the number of terminals attempting to transmit SRS in the uplink SRS radio resource (a) is greater than or equal to a specific number that can be accommodated in the conventional manner, such as FDM or CDM, It is possible to allow some terminals to transmit SRSs in the MU-MIMO scheme by notifying some terminals of the terminals 1, 2 ... according to a predefined policy or selected randomly.

In the above case, the terminal device 100 of the present invention, in particular, the reference signal transmitting unit 120 transmits the SRS in the uplink SRS radio resource (a) in the conventional manner, for example, the FDM scheme or the CDM scheme, ), It is determined that the number of UEs attempting to transmit SRS in the uplink SRS radio resource (a) is greater than or equal to a certain number, and then the SRS will be transmitted in the MU-MIMO scheme as described above.

Meanwhile, when the MU-MIMO SRS transmission is designated by the base station 10, the reference signal transmitter 120 can transmit the SRS in the MU-MIMO scheme as described above.

If the MU-MIMO SRS transmission is not designated by the base station 10, the terminal apparatus 100 of the present invention, in particular, the reference signal transmission unit 120, The SRS is transmitted in the FDM scheme or the CDM scheme, and when the MU-MIMO SRS transmission is designated by the base station 10, the SRS is transmitted in the MU-MIMO scheme as described above.

As described above, according to the present invention, when the SRS is transmitted from the uplink SRS radio resource (a) to the base station 10 in the MU-MIMO scheme, the terminals 1, 2, The number of terminals that can transmit SRS in the radio resource (a) can be increased to the number that can be accommodated by the MU-MIMO scheme.

The base station 10 processes the SRS of each uplink channel according to the MU-MIMO scheme to identify the terminal device 100 as a transmission entity.

That is, the base station 10 will receive the SRS of the uplink channel from a plurality of terminals (e.g., 1, 2 ...) that transmit SRS in the MU-MIMO scheme in the uplink SRS radio resource (a) .

Since the base station 10 knows the precoding matrices of the terminals used for SRS transmission by each of a plurality of terminals (for example, 1, 2, ...), the SRS of each received uplink channel is allocated to the precoding matrix MIMO scheme, it is possible to distinguish a terminal that is a transmission subject that has transmitted the SRS of each uplink channel.

Thus, the base station 10 can measure the channel status of each uplink channel for the terminal device 100 based on the SRS of each uplink channel, which is the transmission subject, by the terminal device 100. [

The base station 10 determines the channel status of each uplink channel measured for the terminal device 100 as the channel status of the downlink channel due to the above-mentioned Dynamic TDD characteristic (reciprocity) It is possible to determine the channel state of each downlink channel with respect to the terminal 100 and to perform optimal beamforming for the terminal apparatus 100 based on the channel state.

As described above, according to the present invention, in a MIMO system using a beamforming technique, a method of determining a channel state of a downlink channel, which is indispensably required for performing optimal beamforming for a terminal, (=> Channel state detection of downlink channel) of the SRS-based uplink channel due to the dynamic TDD feature (reciprocity) instead of the uplink SRS radio resource (a) So that the maximum number of terminals can transmit the SRS.

As a result, according to the present invention, a maximum number of terminals can transmit SRS using the same radio resource, i.e., the uplink SRS radio resource (a), and the base station can transmit downlink channels (&Lt; = channel state estimation of the uplink channel).

Therefore, the present invention is capable of performing optimal beamforming for a maximum number of terminals using a minimum uplink radio resource in a 5G communication technology or the like, which is expected to increase the number of antennas in the future as well as the current MIMO system Environment, it is possible to expect the effect of improving the beam forming performance.

Hereinafter, a reference signal transmission method according to a preferred embodiment of the present invention will be described in detail with reference to FIG.

For convenience of explanation, the terminal device 100 will be referred to as a reference signal transmission method of the terminal device 100 in accordance with the above description. In the following, the operation of the terminal device is indicated by a solid line, and the operation of the base station by a dotted line.

The reference signal transmission method of the terminal device 100 according to the present invention recognizes radio resources that are variably allocated from the base station 10 for transmission of a reference signal (S100).

More specifically, the reference signal transmission method of the terminal device 100 according to the present invention recognizes radio resources that are variable-allocated from the base station 10, that is, uplink SRS radio resources for SRS transmission.

For example, the reference signal transmission method of the terminal device 100 according to the present invention can recognize the uplink SRS radio resource (a) variably allocated from the base station 10 through the information provided on the PDCCH .

The reference signal transmission method of the terminal apparatus 100 according to the present invention is a method for transmitting a reference signal to a base station 10 by transmitting an SRS to a base station 10 in a MU-MIMO manner in a recognized radio resource, i.e., an uplink SRS radio resource a, So that the number of terminals that can transmit the service can be increased (S110).

More specifically, the reference signal transmission method of the terminal apparatus 100 according to the present invention is a method for transmitting a reference signal, which includes uplink (uplink) SRS radio resources (a) And transmits the SRS of the channel to the base station 10 by the MU-MIMO scheme.

For example, assuming that the terminal apparatus 100 includes four antennas as described above, the reference signal transmission method of the terminal apparatus 100 according to the present invention is a method of transmitting uplink signals of four (4) antennas in the uplink SRS radio resource (a) And the SRS of each uplink channel according to the four antenna beams that are beamformed in different directions through the antenna is transmitted to the base station 10 by the MU-MIMO scheme.

In order to perform MU-MIMO communication, the base station 10 recognizes a precoding matrix generated for each of the terminals 1, 2, ..., and each of the terminals 1, 2, And recognizes the generated precoding matrix.

At this time, an algorithm in which a precoding matrix is generated for each of the terminals 1, 2, ..., and a process in which the base station 10 and the terminals 1, 2, The present invention can be adopted in the algorithms and the processes proposed in the related art, and a detailed description thereof will be omitted.

Therefore, the reference signal transmission method of the terminal device 100 according to the present invention uses the uplink SRS radio resource (a) to transmit a plurality of antenna beams that are beamformed in different directions, for example, four The SRS can be transmitted in the MU-MIMO scheme by multiplying the SRS in the uplink channel by the precoding matrix of the terminal apparatus 100 and then transmitting the SRS to the base station 10.

Meanwhile, the reference signal transmission method of the terminal device 100 according to the present invention is a method in which when the number of terminals attempting to transmit SRS in the uplink SRS radio resource (a) is greater than or equal to a specific number that can be accommodated when the MU- The SRS can be transmitted using the MU-MIMO scheme.

Meanwhile, when the SRS transmission of the MU-MIMO scheme is designated by the base station 10, the reference signal transmission method of the terminal device 100 according to the present invention can transmit the SRS in the MU-MIMO scheme as described above.

As described above, according to the present invention, when the SRS is transmitted from the uplink SRS radio resource (a) to the base station 10 in the MU-MIMO scheme, the terminals 1, 2, The number of terminals that can transmit SRS in the radio resource (a) can be increased to the number that can be accommodated by the MU-MIMO scheme.

The base station 10 processes the SRS of each uplink channel according to the MU-MIMO scheme to identify the terminal device 100 as a transmission entity.

That is, the base station 10 will receive the SRS of the uplink channel from a plurality of terminals (e.g., 1, 2 ...) that transmit SRS in the MU-MIMO scheme in the uplink SRS radio resource (a) .

Since the base station 10 knows the precoding matrices of the terminals used for SRS transmission by each of a plurality of terminals (for example, 1, 2, ...), the SRS of each received uplink channel is allocated to the precoding matrix MIMO scheme, it is possible to distinguish the terminal that is the transmission subject that has transmitted the SRS of each uplink channel (S120).

Thus, the base station 10 can measure the channel status of each uplink channel for the terminal device 100 based on the SRS of each uplink channel, which is the transmission subject, by the terminal device 100. [

The base station 10 determines the channel status of each uplink channel measured for the terminal device 100 as the channel status of the downlink channel due to the above-mentioned Dynamic TDD characteristic (reciprocity) (S130) the channel state of each downlink channel with respect to the terminal 100, and perform optimal beamforming for the terminal 100 based on the channel state of the downlink channel (S140).

Then, the reference signal transmission method of the terminal device 100 according to the present invention will repeat step S100 and subsequent steps as long as the terminal operation is not turned off (S150 No).

As described above, according to the present invention, in a MIMO system using a beamforming technique, it is possible to grasp the channel status of the downlink channel for a maximum number of terminals using the same radio resource, It is possible to perform optimal beamforming for a maximum number of terminals using resources, so that the effect of beam forming performance can be expected to be improved.

The reference signal transmission method according to an exemplary embodiment of the present invention may be implemented in the form of a program command that can be executed through various computer means and recorded in a computer readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions recorded on the medium may be those specially designed and configured for the present invention or may be available to those skilled in the art of computer software. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape; optical media such as CD-ROMs and DVDs; magnetic media such as floppy disks; Magneto-optical media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

According to the terminal device and the reference signal transmission method according to the present invention, when the channel state of the downlink channel to the terminal is grasped, it is possible to grasp the channel state of the downlink channel for the maximum number of terminals using the same radio resource Environment, it is not only the use of related technology but also the possibility of commercialization or sales of the applied device is sufficient as it exceeds the limit of the existing technology, It is an invention.

10: Base station
100: terminal device
110: resource holding unit 120: reference signal transmitting unit

Claims (9)

A resource section for recognizing a radio resource variable-allocated from a base station for transmitting a reference signal; And
And a reference signal transmission unit for transmitting a reference signal to the base station in a multi-user-multiple input / output (MU-MIMO) scheme in the radio resource to increase the number of terminals capable of transmitting a reference signal in the same radio resource And the terminal device. The method according to claim 1,
Wherein the reference signal transmitter comprises:
Wherein the base station transmits a reference signal of each uplink channel according to a plurality of antenna beams that are beamformed in different directions in the radio resource to the base station in an MU-MIMO scheme. 3. The method of claim 2,
The base station comprises:
Processing the reference signals of the uplink channels according to the MU-MIMO scheme to identify the terminal devices as the transmission subjects,
And performs channel estimation of a downlink channel for the terminal apparatus based on a channel state of each of the uplink channels measured based on the reference signals of the uplink channels and performs optimal beamforming. Device. The method according to claim 1,
The reference signal,
Wherein the terminal is a Sounding Reference Signal (SRS). The method according to claim 1,
Wherein the reference signal transmitter comprises:
When the number of UEs attempting to transmit a reference signal in the radio resource is greater than or equal to a specific number that can be received when the MU-MIMO scheme is not used or when the reference signal transmission of the MU-MIMO scheme is designated by the base station, the MU- And transmits the reference signal. A method for transmitting a reference signal by a terminal,
A resource recognition step of recognizing radio resources variable-allocated from a base station for reference signal transmission; And
A reference signal transmission step of transmitting a reference signal to the base station by a multi-user-multiple input / output (MU-MIMO) scheme in the radio resource, thereby increasing the number of terminals capable of transmitting a reference signal in the same radio resource And transmitting the reference signal. The method according to claim 6,
Wherein the reference signal transmission step comprises:
And a reference signal of each uplink channel according to a plurality of antenna beams that are beamformed in different directions in the radio resource is transmitted to the base station in an MU-MIMO scheme. 8. The method of claim 7,
The base station comprises:
Processing the reference signals of the uplink channels according to the MU-MIMO scheme to identify the terminal devices as the transmission subjects,
Characterized in that the channel state of the downlink channel to the terminal apparatus is determined based on the channel state of each of the uplink channels measured based on the reference signal of each uplink channel and optimum beamforming is performed Signal transmission method. The method according to claim 6,
Wherein the reference signal transmission step comprises:
When the number of UEs attempting to transmit a reference signal in the radio resource is greater than or equal to a specific number that can be received when the MU-MIMO scheme is not used or when the reference signal transmission of the MU-MIMO scheme is designated by the base station, the MU- And transmitting the reference signal.

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