KR102184318B1 - Method and apparatus for beam selection in wireless communication system - Google Patents

Abstract

According to an embodiment of the present invention, in a method for selecting a beam of a base station in a wireless communication system, a control channel including downlink control information (DCI) is used using a plurality of beams. And transmitting to at least one terminal, transmitting a data channel scheduled with the downlink control information to the terminal, receiving a response channel for the data channel from the terminal, and the response channel Based on the reception, it is possible to provide a method and a base station apparatus comprising the step of selecting at least one beam to be used for the terminal from among the plurality of beams. In addition, a communication method and apparatus for a terminal communicating with the base station can be provided.

Description

Method and apparatus for beam selection in wireless communication system {METHOD AND APPARATUS FOR BEAM SELECTION IN WIRELESS COMMUNICATION SYSTEM}

The present invention relates to a method and apparatus for selecting a beam in a wireless communication system.

In addition, the present invention relates to a method for selecting an optimal beam used to transmit a data signal to a terminal in downlink when a base station has a plurality of antennas. In addition, the present invention relates to a control channel transmission method of a base station for this purpose, a method for the base station to determine an optimal beam, and an efficient data transmission and terminal operation method using the same.

In general, mobile communication systems have been developed for the purpose of providing communication while securing user mobility. These mobile communication systems have reached the stage of providing high-speed data communication services as well as voice communication thanks to the rapid development of technology.

In recent years, as one of the next-generation mobile communication systems, standard work for a Long Term Evolution (LTE) system is in progress in the 3rd Generation Partnership Project (3GPP). The LTE system is a technology that implements high-speed packet-based communication with a transmission speed of up to 100 Mbps, which is higher than the currently provided data rate, with the target of commercialization in 2010, and the standardization is almost completed. In line with the completion of the LTE standard, discussions on an evolved LTE system (LTE-Advanced, LTE-A) that further improve the transmission speed by incorporating various new technologies into the recent LTE communication system are in earnest. Hereinafter, the term “LTE system” will be understood to mean including an existing LTE system and an LTE-A system.

The technical problem to be achieved by the present invention is to provide a method and apparatus for selecting a beam in a wireless communication system.

According to an embodiment of the present invention, in a method for selecting a beam of a base station in a wireless communication system, a control channel including downlink control information (DCI) is used using a plurality of beams. And transmitting to at least one terminal, transmitting a data channel scheduled with the downlink control information to the terminal, receiving a response channel for the data channel from the terminal, and the response channel Based on the reception, it may provide a method comprising the step of selecting at least one beam to be used for the terminal from among the plurality of beams.

In addition, according to an embodiment of the present invention, in a base station for selecting a beam used in a wireless communication system, a transceiver for performing data communication with at least one network node and downlink control information (DCI, Downlink A control channel including Control Information) is transmitted to at least one terminal using a plurality of beams, and a data channel scheduled with the downlink control information is transmitted to the terminal, And a control unit for receiving a response channel for the data channel from the terminal and controlling to select at least one beam to be used for the terminal from among the plurality of beams based on the reception of the response channel. It can provide a base station.

In addition, according to an embodiment of the present invention, in a communication method of a terminal in a wireless communication system, a plurality of beams formed by a base station are provided with a control channel including downlink control information (DCI). Receiving through (beam), receiving a data channel scheduled for the control channel from the base station, based on the received control channel, a response channel for receiving the data channel to the base station It is possible to provide a method comprising the step of transmitting and receiving a downlink from the base station through a beam selected by the base station based on the response channel.

In addition, according to an embodiment of the present invention, in a terminal performing wireless communication, a transmission/reception unit performing data communication with at least one network node, and a control channel including downlink control information (DCI) (Control Channel) is received through a plurality of beams formed by a base station, a data channel scheduled for the control channel is received from the base station, and based on the received control channel, the data It is possible to provide a terminal comprising a control unit for transmitting a response channel for channel reception to the base station and for controlling to receive a downlink from the base station through a beam selected by the base station based on the response channel. .

According to an embodiment of the present invention, a method and apparatus for selecting a beam of a base station in a wireless communication system are provided.

In addition, according to an embodiment of the present invention, the base station may determine the location of the terminal based on the downlink between the base station and the terminal, select a beam, and perform communication with the terminal through the selected beam.

In addition, according to an embodiment of the present invention, the base station may determine the spatial location of the terminal based on response information for downlink reception without using uplink between the base station and the terminal. In particular, an embodiment of the present invention may be more effective in an FDD system in which uplink and downlink use different frequency bands.

Further, according to an embodiment of the present invention, the base station may determine an optimal beam from a beam used by the base station without transmitting the type and number of beams used by the base station, a beam width, and related information to the terminal.

In addition, according to an embodiment of the present invention, it is possible to select an optimal beam of a terminal without changing an existing system, and can be applied regardless of the number, shape, and antenna gain of the beams used by the base station. In addition, it can be operated without delivering additional information to the terminal. It is also useful when it is difficult to use a channel estimated in uplink for downlink by using different frequency bands for uplink and downlink.

1 is a diagram illustrating spatial locations of a base station and a terminal.
FIG. 2A is a diagram illustrating a process in which a base station configures a control channel, and FIG. 2B is a diagram illustrating a process in which a terminal receives a control channel.
3 is a diagram illustrating a transmission process of a downlink control channel of a base station.
4 is a diagram illustrating a process of transmitting a control channel using a plurality of downlink beams of a base station.
5 is a diagram illustrating a downlink transmission method of a base station according to an embodiment of the present invention.
6 is a diagram illustrating a process of transmitting a response channel from a terminal and determining an optimal beam by a base station through the transmission of a response channel according to an embodiment of the present invention.
7 is a diagram illustrating a downlink transmission method of a base station according to a second embodiment of the present invention.
8 is a diagram illustrating a downlink transmission method of a base station according to a third embodiment of the present invention.
9 is a diagram illustrating a downlink transmission method of a base station according to a fourth embodiment of the present invention.
10 is a diagram illustrating a downlink transmission method of a base station according to a fifth embodiment of the present invention.
11 is a diagram illustrating a downlink transmission method of a base station according to a sixth embodiment of the present invention.
12 is a diagram illustrating a downlink transmission method according to a seventh embodiment of the present invention.
13 is a flowchart illustrating a method of recognizing an optimal beam for a terminal of a base station according to an embodiment of the present invention.
14 is a flowchart illustrating a method of transmitting a response channel by a terminal according to an embodiment of the present invention.
15 is a diagram illustrating beam formation of a base station according to an embodiment of the present invention.
16 is a diagram illustrating a base station according to an embodiment of the present invention.
17 is a diagram illustrating a terminal according to an embodiment of the present invention.

Hereinafter, various embodiments will be described in detail with reference to the accompanying drawings. In this case, it should be noted that the same components in the accompanying drawings are indicated by the same reference numerals as possible. In addition, detailed descriptions of known functions and configurations that may obscure the subject matter of the present invention will be omitted. In the following description, it should be noted that only parts necessary to understand the operation according to various embodiments of the present invention will be described, and descriptions of other parts will be omitted so as not to obscure the gist of the present invention.

According to the following embodiments of the present invention, a method and apparatus for selecting a beam in a wireless communication system may be provided. According to an embodiment of the present invention, when a base station communicates with a terminal using a plurality of antennas, the base station may form beams in various spaces and transmit the plurality of antennas using different antenna gains.

In the present invention, a beam refers to a method in which a base station collects and transmits energy in a spatially desired direction by using a phase difference between antennas using a plurality of antennas in a downlink. The configuration of the beam by the base station means that more energy can be collected and transmitted to an area in which a specific terminal is located, and thus, interference of less energy may occur in other directions, thereby improving reception performance. When the number of antennas of the base station increases, the directionality of the beam that can be formed and configured by the base station increases as well as more energy can be collected. Therefore, forming the beam of the base station is very useful in a system where the number of antennas is very increased. .

When the base station communicates by forming a beam in a specific space, the base station can deliver a higher quality signal to the terminal in the corresponding space, thereby improving cell performance. However, since the base station cannot actually determine the spatial location of the terminal, a technique for estimating this is required. The base station generally estimates the location of the terminal based on the signal transmitted by the terminal, but since various types of obstacles exist between the terminal and the base station, the accuracy of the actually estimated location is not high. In addition, since the beam that can be formed by the base station does not exactly match the space in which the terminal is located, it is difficult to determine which beam is the best beam in the downlink even if the approximate spatial position of the terminal is estimated with the signal transmitted by the terminal. An embodiment of the present invention proposes a technique for the base station to determine the optimal beam by using a method other than a signal transmitted from a terminal (eg, a sounding reference signal (SRS)).

In an embodiment of the present invention, in order to solve the above problem, in order to solve the above problems, a method of configuring a control channel and a method of configuring a control channel, and a resource for transmitting the configured control channel to a plurality of beams are used as a base station operation for a beam selection method and an apparatus in the wireless communication system Allocating a beam, forming a beam using different antenna gains to the assigned control channel, transmitting a data channel based on control channel information, forming a beam for data channel transmission, and transmitting data The process of determining the energy of the response channel of the terminal for the channel, the process of demodulating the response channel transmitted by the terminal, and the process of determining the optimal beam among multiple beams used for the control channel using the response channel transmitted by the terminal. Include.

In a wireless communication system, a terminal operation for a method and apparatus for selecting a beam in a wireless communication system of the present invention, a process of receiving a control channel, a process of receiving a data channel based on the received control channel, and determining whether the data channel is successfully received And a process of transmitting an uplink response channel according to success or failure.

In addition, in order to solve the above problems, as a base station operation for a beam selection method and apparatus in the wireless communication system of the present invention, the base station has different control channels to transfer common control to terminals located spatially in a cell. A method of configuring, a process of allocating resources to transmit a configured control channel to a plurality of beams, a process of forming a beam using different antenna gains for the assigned control channel, and transmitting a data channel based on control channel information And a process of forming a beam for data channel transmission.

In addition, in order to solve the above problems, as a base station operation for a beam selection method and apparatus in a wireless communication system of the present invention, the base station transmits to one terminal to transmit a control channel for a data channel using different beams. Beam forming using different antenna gains according to the format of the control channel, transmitting a data channel based on control channel information, and forming a beam for data channel transmission.

In addition, in order to solve the above problems, as a base station apparatus for a beam selection method and apparatus in a wireless communication system according to the present invention, a control channel configurator constituting a control channel, a control channel for transmitting the control channel through different beams. A selector, an antenna gain selector for applying different beams, a receiver for receiving an uplink response channel, and a demodulator for demodulating an uplink response channel.

The present invention is for a communication system for transmitting a downlink signal from a base station to a terminal and an uplink signal from a terminal to a base station. The downlink signal includes a data channel including information transmitted to the terminal, a control channel for transmitting a control signal, and a reference signal (RS) for channel estimation and channel feedback. The base station transmits data information and control information to the terminal through a physical downlink shared channel (PDSCH) and a downlink control channel (DL CCH), respectively. The uplink consists of a data channel, a control channel, and a reference signal transmitted by the terminal. The feedback information of the data channel or the terminal is transmitted through a PUSCH (Physical uplink shared channel), and the response channel for the downlink data channel or the feedback information of the terminal is transmitted through a physical uplink control channel (PUCCH).

The base station may have a plurality of reference signals. The plurality of reference signals include a common reference signal (CRS), a channel stat information RS (CSI-RS), and a demodulation signal or a terminal-specific reference. There is a signal (DMRS, demodulation reference signal). The CRS is transmitted over the entire downlink band, and all terminals in the cell are used for signal demodulation and channel estimation. In order to reduce the resources used for CRS transmission, the base station transmits the terminal-dedicated reference signal (DMRS) only to the scheduled area of the terminal by using the terminal-dedicated reference signal, and CSI in the time and frequency axis to acquire channel information -RS can be transmitted.

1 is a diagram showing spatial locations of a base station and a terminal. Referring to FIG. 1, the base station 101 may have a plurality of antennas. The base station may use a plurality of antennas to form various types of beams suitable for different terminals spatially located in their coverage. For example, if each of the terminals 103, 105, and 107 are located at different distances from the base station as shown in FIG. 1, the base station forms different beams 115, 113, 111 as shown in FIG. Can allow the highest signal quality to be reached. The beam formed as described above may be used for data transmission, and may be used for transmission of a reference signal or transmission of a control channel. A plurality of different beams as described above may be configured by a base station using a plurality of antennas. In an embodiment of the present invention, a base station transmission method in which a base station uses multiple beams for a data channel, a transmission method for a reference signal, a transmission method for a control channel, and a method for transmitting using a combination thereof are all included. .

FIG. 2A is a diagram illustrating a process in which a base station configures a control channel, and FIG. 2B is a diagram illustrating a process in which a terminal receives a control channel.

Referring to FIG. 2A, in step 201, the base station configures a control channel (PDCCH), and in step 203, the base station performs coding of the control channel. In step 205, the base station determines a coding rate in consideration of the amount of transmission resources. In step 205, the base station concatenates a cyclic redundancy check (CRC) so that each terminal can determine whether to receive its own control channel. At this time, the base station concatenates the unique identifier of the transmitted terminal by taking a bit-wise XOR operation to the CRC. The terminal has an area where each terminal can receive a control channel. In step 209, the base station arranges a control channel so that each terminal can perform demodulation in an area where each terminal can receive a control channel.

Referring to FIG. 2B, in step 211, the UE receives a control channel area (or search space) and reads a control channel of its own area from the corresponding area. Among each region, there is a control channel candidate region of the terminal. The control channel candidate region refers to a set that can be candidates of control information for the terminal in each region, and this may mean a set of at least one element (eg, CCE) having different starting points. have. In step 213, the UE performs control channel demodulation by attempting to demodulate all of the candidate regions. In step 215, the UE may determine whether demodulation is successful for the candidate region. The determination may be performed by the terminal through CRC verification. The terminal checks the CRC using the terminal's own identifier, and determines whether the control channel attempted demodulation is a control channel transmitted to the terminal.

If the CRC check is passed in step 215, the terminal proceeds to step 217 to analyze downlink control information (DCI), which is information on the control channel. In step 219, the terminal can receive and demodulate the data channel scheduled by the base station using this. In step 221, the UE determines ACK/NACK according to whether reception of the corresponding data channel is successful after demodulation, and transmits this to the base station through the PUCCH, which is an uplink control channel.

The resources of the uplink control channel are configured using the lowest index of the control channel index used by the control channel in which the CRC pass has been made among the received control channel candidates. For example, when a control channel is configured and transmitted using a plurality of CCE (Control Channel Element) indexes of one control channel, such as in the LTE system, if the control channel is transmitted using CCE indexes 3, 4, 5, 6, uplink The resource index of the response channel is transmitted using the lowest index 3 and one-to-one mapped resource among the received control channel indexes.

Transmission of the downlink control channel of the base station is transmitted using a common reference signal or a dedicated reference signal. The data channel transmission of the base station can use both a common reference signal and a dedicated reference signal, which is indicated to the terminal based on information transmitted on the control channel.

3 is a diagram illustrating a transmission process of a downlink control channel of a base station. Referring to FIG. 3, in step 301, the base station configures a control channel using downlink control channel information (DCI). The control channel is composed of a physical downlink control channel (PDCCH) or an enhanced PDCCH (EPDCCH) through a process as described in FIG. 2. In step 305, the base station performs layer mapping according to a control channel transmission method. For example, in the case of a PDCCH, which is a control channel transmitted using a common reference signal, it is mapped to all transmitted layers and transmitted. In the case of the EPDCCH, which is a control channel transmitted using a dedicated reference signal, the transmitted control channel is mapped according to a used layer and transmitted.

In step 307, the base station performs IFFT according to the transmission bandwidth. In step 309, the base station performs a process for OFDM transmission (P/S mapping, cyclic prefix addition, and digital to analog conversion). In step 311, the base station transmits a signal to each antenna 313 through an amplifier and carrier modulation.

The operation as shown in FIG. 3 is generally a structure when a base station uses one fixed downlink beam to transmit a control channel. In the case of the existing system, in order to transmit a control channel, a base station antenna must form a certain coverage, and for this, it is important to continuously transmit a control channel using a fixed beam to secure coverage.

However, as the scale of the system and the occurrence of antenna transmission technology, the number of antennas of the base station also increases, and thus, a technology capable of transmitting using a plurality of beams can be used. For this purpose, the structure shown in FIG. 4 may be used. As for the technique in which the base station uses a plurality of beams, another method exists in FIG. 4, and the present specification is described with reference to FIG. 4, but the present invention can be equally applied to a base station using a plurality of beams with a different structure.

4 is a diagram illustrating a process of transmitting a control channel using a plurality of downlink beams of a base station.

Referring to FIG. 4, in step 401, the base station configures a control channel using control channel information (DCI), and in step 403, the base station configures a control channel of the PDCCH or EPDCCH so that the terminal can receive it. In step 405, the base station maps each control channel to a suitable layer according to the transport channel, as described in step 305 of FIG. 3. The mapped control channels generate different OFDM signals through different paths. For example, when the base station uses two control channel beams, one path generates an OFDM signal through paths 407, 409, and 411 in FIG. 4 and the other path through paths 417, 419, and 421 in FIG. 4. . In steps 413 and 423, the base station applies antenna gains for different downlink beams used for transmission, adds them to the same antenna, and transmits them. In this case, one control channel is transmitted to the terminal through different downlink beams.

An embodiment of the present invention relates to a method for a base station to select an optimal beam for a specific terminal in a system using different downlink beams for a control channel as shown in FIG. 4. Each embodiment for this will be described in more detail below. Hereinafter, each embodiment will be described separately, but each embodiment may operate independently, and may be implemented through a combination of each embodiment at the skill level of those skilled in the art.

First, a first embodiment of the present invention will be described based on FIGS. 5, 6 and 15. FIG. 5 is a diagram illustrating a downlink transmission method of a base station according to an embodiment of the present invention, and FIG. 6 is a diagram illustrating a process of transmitting a response channel of a terminal and a process by which the base station determines an optimal beam, 15 is a diagram illustrating beam formation of a base station according to an embodiment of the present invention.

In the first embodiment of the present invention, the base station transmits the same arbitrary control channel information (downlink control information, DCI, Downlink Control Channel) to different control channel candidate regions, and in this case, each control channel candidate This is a method of transmitting by using an antenna gain to generate a. In this case, the base station transmits a data channel or a common reference signal scheduled for a corresponding control channel by using all beams used for each control channel. The terminal receives the control channel through thirty different beams, and transmits the response channel of the uplink control channel based on the lowest control channel index in the received control channel. In this case, the base station is a method of determining a beam that guarantees better signal quality to the terminal from among the beams used for the control channel according to whether the response channel is received.

Referring to FIG. 5, the base station configures control channel information (DCI, 501) to transmit a control channel for transmitting a downlink data channel to an arbitrary terminal. A plurality of control channel transmission candidates exist in the control channel region of the corresponding terminal, and the corresponding terminal receives all control channel candidates existing in the corresponding region. Accordingly, the base station can allocate the same control channel in different control channel candidate regions according to the number of used beams. For example, as shown in FIG. 5, when the base station uses two beams, the base station may allocate the same control channel to candidate A (PDCCH candidates A, 503) and candidate B (PDCCH candidates B, 509). This can be applied equally to the case of using two or more beams, and in this case, two or more candidates can be used or beams can be applied to different candidates at different time points in time according to the beam order.

The base station may apply different beams 505 and 511 to each candidate. That is, the base station can apply antenna gains for different downlink beams used for transmission. In this case, each candidate can be transmitted using different time/frequency resources, and thus the same control channel can be simultaneously transmitted through different beams.

The base station generates a common reference signal (CRS, 513) and a data channel (PDSCH, 513). Thereafter, the base station may apply all of the beams 515 and 519 used by the control channel for transmission of the common reference signal and the data channel. Thereafter, the base station transmits a common reference signal and a data channel to which the same beam as the control channel is applied through the summer 517. In this way, although the control channel is transmitted through different beams, the base station transmits the data channel so that the terminal can always receive it in all spaces.

This is a result of beam selection in the reception performance of the control channel, and is a method for removing the effect of the reception performance of the data channel. No matter which one of the two control channels the UE successfully receives, the UE estimates the channel through a common reference signal and can receive a data channel. The terminal transmits only the response channel for the data channel and different response channels according to the control channel received by the terminal. That is, according to the case where the terminal receives the control channel of candidate A and the case where the terminal receives the control channel of candidate B, the channel through which the response channel to the data channel of the terminal is transmitted is different from each other. The base station can identify the control channel received by the terminal and the beam through which the control channel is transmitted, based on the response channel received from the terminal, and can select the identified beam and use it for communication with the terminal.

6 is a diagram illustrating a process of transmitting a response channel by a terminal and a process in which a base station determines an optimal beam through the transmission of a response channel. Referring to FIG. 6, the UE determines whether or not the received data channel is successfully received and determines ACK or NACK. If data channel reception is successful, it is determined as ACK, and if data channel reception is unsuccessful, it is determined as NACK. The UE determines an uplink control channel resource for transmitting the determined ACK and NACK using the index of the received control channel, and transmits the determined ACK or NACK information using the determined control channel resource. Since the base station transmits the same control channel to different control channels, the number of resources 601 and 609 of the response channel that the terminal can transmit can be expected to be two. Accordingly, for the corresponding resource, the base station determines the resource of the response channel used by the corresponding terminal through the presence or absence of received power of the signal at the time of transmission of the terminal (603). Thereafter, the base station demodulates the response channel in the corresponding resource (605). Through this, the control channel controller 607 of the base station determines which control channel is correctly received by the terminal, and can determine whether the beam used for transmission of the corresponding control channel is the best beam.

If the base station uses multiple beams, the base station selects random N beams from a number of beams at a random scheduling point and transmits N different beams to the N control channel transmission candidates. Can judge the beam.

When this is described in terms of a beam used by the base station, referring to FIG. 15, the base station 1501 may transmit a control channel through two beams 1505 and 1507. The corresponding terminal 1509 will receive a control channel transmitted through a beam 1505 that is optimal for itself among two control channels. At this time, the data channel transmitted by the base station is transmitted using both different beams (1505, 1507) as shown in reference numeral 1511, and even when receiving the response channel from the terminal, the base station is in all directions as shown in reference numeral 1511. You can receive a response channel at In an embodiment of the present invention, the base station does not rely on uplink because the base station does not estimate the direction of the signal transmitted by the terminal when receiving transmission from the terminal, and the base station transmits a control channel using additional resources, and the response channel This is a method of determining a beam more suitable for a terminal through the presence or absence of resource transmission. The process of determining the optimal beam by the base station may be applied in the same or similar manner in all embodiments described later.

The proposed method can select the optimal beam of the terminal without changing the existing system, and can be applied regardless of the number, shape, and antenna gain of the beam used by the base station, and without transmitting additional information to the terminal. Can be operated. Also, it is useful when it is difficult to use a channel estimated in the uplink for downlink by using different frequency bands for uplink and downlink.

Next, a second embodiment of the present invention will be described. In the second embodiment of the present invention, the base station transmits arbitrary control channel information to different control channel candidate regions in time, and at this time, transmits and transmits antenna gains for generating different beams for each control channel candidate. That's the way. In this case, the base station transmits a data channel or a common reference signal scheduled for a corresponding control channel by using all beams used for each control channel. The terminal receives the control channel through thirty different beams at different times and transmits the response channel of the uplink control channel based on the lowest control channel index in the received control channel. In this case, the base station is a method of determining a beam that guarantees better signal quality to the terminal from among the beams used for the control channel according to whether the response channel is received.

7 is a diagram illustrating a downlink transmission method of a base station according to a second embodiment of the present invention. Referring to FIG. 7, the base station configures control channel information 701 to transmit a control channel for transmitting a downlink data channel to an arbitrary terminal. A plurality of control channel transmission candidates exist in the control channel region of the corresponding terminal, and the corresponding terminal receives control channels to all candidates existing in the corresponding region. The base station may select an arbitrary candidate and arrange a control channel regardless of the number of used beams. For example, when the base station uses two beams, the same control channel 703 is arranged using different beams at different transmission timings. At this time, the beam used for the control channel uses the same beam for transmission of the data channel scheduled by the corresponding control channel.

In this case, transmission is possible through different beams at different timings. In this case, different control channel indexes may be transmitted at different timings, and transmission may be performed using only one beam at a time. The base station configures the common reference signal 711 by applying all of the beams 713 and 715 that can be used by the control channel, and transmits it through the summer 717. In this way, although the control channel is transmitted through different beams, the reference signal is always transmitted in all beams used by the base station in the space where the terminal is located.

This method is a method capable of preventing additional use of control channel resources by transmitting the same control channel to a plurality of candidates as in the first embodiment when the base station operates a plurality of beams. According to the second embodiment of the present invention, whether the terminal successfully receives one of the two control channel transmission timings, the base station can use the terminal for downlink through the response channel for the reception of the data channel. There is an optimal beam to be recognized. The method described in the first embodiment may be applied to a method for the base station to transmit a response channel for reception of a data channel and a method for selecting an optimal beam based on the response channel received by the base station.

In the third embodiment of the present invention, the base station transmits information on the same random control channel to different control channel candidate regions, and transmits and transmits antenna gains for generating different beams for each control channel candidate. to be. In this case, the base station selectively uses one of the beams used by the control channel for the data channel scheduled for the corresponding control channel, and transmits the common reference signal using all the beams used for each control channel. The terminal receives the control channel through thirty different beams and transmits a response channel of the uplink control channel based on the lowest control channel index in the received control channel. In this case, the base station is a method of determining a beam that guarantees better signal quality to the terminal from among the beams used for the control channel according to whether the response channel is received.

8 is a diagram illustrating a downlink transmission method of a base station according to a third embodiment of the present invention. Referring to FIG. 8, the base station configures control channel information 801 to transmit a control channel for transmitting a downlink data channel to an arbitrary terminal. A plurality of control channel transmission candidates exist in the control channel region of the corresponding terminal, and the corresponding terminal receives control channels to all candidates existing in the corresponding region. Accordingly, the base station can allocate the same control channel to different candidates according to the number of used beams. For example, when the base station uses two beams, the base station allocates the same control channel to candidate A (803) and candidate B (809). This can be applied equally to the case of using two or more beams.

Thereafter, the base station applies different beams 805 and 811 to each candidate. In this case, each candidate can be transmitted using different time/frequency resources, and thus the same control channel can be simultaneously transmitted through different beams.

The base station applies all of the beams 817 and 821 used by the control channel to the common reference signal 815 and transmits the same through the summer 817. However, the data channel 813 selectively uses an arbitrary beam from among the beams used by the control channel through the selector 811. Even if the terminal correctly receives the control channel through a specific beam, the terminal may artificially induce NACK or ACK by transmitting the data channel irrespective of the reception of any control channel. According to the third embodiment of the present invention, the base station can prevent an error in determining the power of the response channel transmitted by the terminal. For example, when the base station transmits control channels 1 and 2 through beams A and B, respectively, and the data channel uses beam A, when the terminal uses beam B, the terminal is connected to the response channel linked to the resource of control channel 2. When the NACK is transmitted and beam A is optimal, the ACK is transmitted on the response channel linked to the resource of control channel 1. Accordingly, the base station can determine the optimal beam by additionally using information of ACK and NACK as well as the power size of the response channel.

According to a fourth embodiment of the present invention, in transmitting information about the same random control channel to different control channel candidate regions, the base station transmits different beams to each control channel transmission physical resource block set (PRB set). This is a method of transmitting by transmitting an antenna gain for generating a signal. The fourth embodiment is a method in which a base station transmits a data channel scheduled for a corresponding control channel and a dedicated reference signal by selectively using one of the beams used by the control channel. The terminal receives the control channel through thirty different beams, and transmits the response channel of the uplink control channel based on the lowest control channel index in the received control channel. In this case, the base station may determine a beam that guarantees better signal quality to the terminal from among the beams used for the control channel according to whether the response channel is received.

9 is a diagram illustrating a downlink transmission method of a base station according to a fourth embodiment of the present invention. Referring to FIG. 9, the base station configures control channel information 901 to transmit a control channel for transmitting a downlink data channel to an arbitrary terminal. The corresponding control channel refers to a control channel transmitted using a terminal-specific reference signal. A number of control channel transmission candidates exist in the control channel region of the corresponding terminal. The candidate may be configured by the base station allocating a maximum of two control channel sets to each terminal. The corresponding terminal receives a control channel from all candidates existing in the corresponding region. Accordingly, the base station may allocate the same control channel to different candidates according to the number of beams to be used, and transmit through different beams.

For example, when the base station uses two beams, the base station allocates the same control channel in the candidate regions of the control channel set A 903 and the control channel set B 909. This can be applied equally to the case of using two or more beams. After that, each candidate transmits by applying different beams 905 and 911. In this case, each candidate can be transmitted using different time/frequency resources, and thus the same control channel can be simultaneously transmitted through different beams. Since the response channel transmitted by the terminal is separately allocated to different regions for each configured control channel set, the base station can select an optimal beam from among different beams through this. The base station may select a beam to be used for communication with the terminal based on an area to which a corresponding response channel is allocated to the data channel from the terminal.

The fifth embodiment of the present invention is an antenna for generating different beams to a dedicated reference signal used for each of the control channel transmission candidate resources when the base station transmits the same random control channel information to different control channel candidate regions. This is a method of transmitting by applying a gain. The fifth embodiment of the present invention is a method in which a base station transmits a data channel scheduled for a corresponding control channel and a dedicated reference signal by selectively using one of the beams used by the control channel. The terminal receives the control channel through thirty different beams, and transmits the response channel of the uplink control channel based on the lowest control channel index in the received control channel. In this case, the base station may determine a beam that guarantees better signal quality to the terminal from among the beams used for the control channel according to whether the response channel is received.

10 is a diagram illustrating a downlink transmission method of a base station according to a fifth embodiment of the present invention. Referring to FIG. 10, the base station configures control channel information 1001 in order to transmit a control channel for transmitting a downlink data channel to an arbitrary terminal. The corresponding control channel refers to a control channel transmitted using a terminal-specific reference signal. A number of control channel transmission candidates exist in the control channel region of the corresponding terminal. The terminal receives a control channel present in at least one of a maximum of two candidate control channel sets. Accordingly, the base station may allocate the same control channel to different candidates using different terminal reference signals according to the number of used beams, and may also transmit the disposed control channels through different beams. For example, when the base station uses two beams, the same control channel is disposed in the candidate region by using different dedicated reference signals 1009 and 1011 for the control channel candidate A 1003 and the candidate B 1011. This can be applied equally to the case of using two or more beams.

After that, each candidate is transmitted by applying different beams 1005 and 1015. In this case, each candidate may be transmitted using a different time/frequency resource, or may use the same time/frequency resource at the same time, but may be transmitted through a different dedicated reference signal. Response channels transmitted by the terminal are separately allocated to different regions for each dedicated reference signal used in the configured control channel set. Accordingly, the base station can select an optimal beam from among different beams through this.

According to a sixth embodiment of the present invention, a base station configures a plurality of control channel information having different scheduling information for delivering a plurality of different system information to operate one or more sectors in a cell using the same cell identifier. This configuration information is a control channel for scheduling system information delivery. This control information is arranged in different common control candidate regions and simultaneously transmitted using different beams for each candidate.

11 is a diagram illustrating a downlink transmission method of a base station according to a sixth embodiment of the present invention. Referring to FIG. 11, the base station may arbitrarily operate one or more virtual cells for terminals accessing the same cell identifier. To this end, different types of system information must be transmitted through the same cell identifier. However, no matter how well the base station separates the control channels spatially, interference between them occurs. Therefore, it is difficult to deliver different information to an arbitrary set of terminals rather than an arbitrary terminal. However, the problem can be solved through the control channel transmission proposed in the embodiment of the present invention.

For example, when different system information 1109 and 1121 needs to be transmitted, the base station may configure control channel information 1101 and 1119 in order to transmit system information to each other. The control channel information may be composed of the same information or different information. If the control channel information is configured with the same information, the base station will assign control channel information (1101, 1119) to candidate A (1103) and candidate B (1111) in the area of the common control channel that all terminals should receive. I can. In addition, when transmitting the corresponding control channel, it is transmitted through different beams, and since different control channel candidates use different resources in time/frequency, when actually received by the terminal, it can be received without interference between the beams. If the data channels 1113 and 1123 for transmitting system information are different, the terminal can deliver the system information without problems that different system information 1109 and 1121 are mixed even if a control channel reception error occurs. have. To this end, the common reference signal is transmitted using all the beams 1127 used by the base station in the same manner as in the first embodiment, and the actual transmission is transmitted in a form in which all signals applied to each beam are added.

The seventh embodiment of the present invention is a method of transmitting a control channel when a base station uses various data transmission techniques that transmit to a terminal using different beams. If an arbitrary terminal operates two transmission modes using different beams, the base station transmits the control channel using the beam used for the data channel for control channel transmission.

Referring to FIG. 12, the base station may apply different types of beams according to the transmission mode of the data channel transmitted to the terminal. For example, in order for the base station to maximize spatial multiplexing gain, it is necessary to secure at least one independent channel between the base station and the terminal through a relatively wide beam in a specific direction. If the base station wants to apply multi-user multiplexing, the base station needs to secure a multi-user transmission gain by applying a beam having a relatively small beam width to different terminals. If the base station determines that all of the above-described transmission modes fail or the terminal moves very quickly, it will be advantageous for the base station to use a data transmission method randomly transmitted in all directions. For these transmission modes, the system configures different control channel formats. If the beam used in the data channel is also used for the control channel, reception quality of the control channel may be improved. In addition, when one base station uses multiple beams, there may be a case where the actual movement of the terminal becomes faster than the time when the base station tracks the spatial location of the terminal. In this case, in order to more adaptively apply different channel changes, the base station may transmit different control channel formats by using different beams. In the proposed seventh embodiment, such a control channel transmission method is proposed.

12 is a diagram illustrating a downlink transmission method according to a seventh embodiment of the present invention. Referring to FIG. 12, when the format of the control channel is different, the base station may transmit each format to different control channel candidates, such as candidate A 1203 and candidate B 1211. The base station may selectively transmit the beam of the corresponding control channel through the beam selector 1205 according to the transmission method of the data channel actually scheduled by the control channel. In addition, the data channel or the reference signals 1213 and 1215 for the same can also improve reception performance by applying the same beam.

13 is a flowchart illustrating a method of recognizing an optimal beam for a terminal of a base station according to an embodiment of the present invention. Referring to FIG. 13, in step 1301, the base station assigns a control channel to a control channel transmission candidate in order to transmit control channel information. Thereafter, in step 1303, the base station applies a specific beam to each of the arranged control channels. Thereafter, in step 1305, the base station transmits the control channel and the data channel indicated by the control channel to the terminal. Subsequently, in step 1307, the terminal transmits an ACK or NACK to the base station through a response channel using whether or not the data channel has been successfully received and the index of the control channel resource of the received control channel. Afterwards, in step 1309, the base station determines whether the response channel is transmitted by measuring the power of the response channel resource actually transmitted by the terminal among the resources of the response channel used by the base station, and which beam is optimal for downlink of the terminal through this. Judge.

14 is a flowchart illustrating a method of transmitting a response channel by a terminal according to an embodiment of the present invention. Referring to FIG. 14, the terminal receives a control channel and a data channel in step 1401. In step 1403, the terminal determines the response channel resource using the received control channel resource index and the used reference signal index or a combination of the two. In step 1405, the terminal finally transmits the response channel resource including information on whether or not the data channel is successfully received. Thereafter, the terminal may perform communication with the base station through a beam selected by the base station based on the response channel transmitted by the terminal. The terminal may receive a downlink from the base station through the selected beam.

16 is a diagram illustrating a base station apparatus according to an embodiment of the present invention.

The base station 1600 may include a transceiver unit 1610 and a control unit 1630. The transmission/reception unit 1610 may perform data communication with at least one network node. In an embodiment of the present invention, the transmission/reception unit may transmit a downlink channel and receive an uplink channel.

The controller 1630 may control the overall operation of the base station. Further, according to an embodiment of the present invention, the control unit 1630 includes: a transmission/reception unit for performing data communication with at least one network node; And

Data that transmits a control channel including downlink control information (DCI) to at least one terminal using a plurality of beams, and is scheduled with the downlink control information Transmits a channel to the terminal, receives a response channel for the data channel from the terminal, and controls to select at least one beam to be used for the terminal from among the plurality of beams based on the reception of the response channel I can.

In addition, the controller 1630 arranges a plurality of control channels including the same downlink control information in different control channel candidate regions, and transmits the control channels arranged in each of the control channel candidate regions through different beams. Can be controlled.

In addition, the controller 1630 may control to transmit the same data channel and a common reference signal (CRS) using all beams used for transmission of the control channel.

In addition, the control unit 1630 controls the terminal to determine the beam on which the control channel was received based on the received response channel resource, and to select the beam on which the terminal has received the control channel as a beam for the terminal. I can. In this case, the resource of the response channel may be determined based on the index of the control channel received by the terminal.

Further, the controller 1630 arranges a control channel including the same downlink control information in one control channel candidate region, applies different antenna gains to the control channel, and applies different antenna gains to the control channel. It is possible to control the transmission to be transmitted using different beams at different timings.

In addition, the controller 1630 transmits a common reference signal (CRS) using all beams used for transmission of the control channel, and transmits a data channel to one of all beams used for transmission of the control channel. You can control to select and transmit. In addition, the control unit 1630 determines a beam in which the terminal has received a control channel based on ACK/NACK information of the received response channel, and selects a beam in which the terminal has received the control channel as a beam for the terminal. Can be controlled to do.

In addition, the control unit 1630 determines a beam in which the terminal has received a control channel based on ACK/NACK information of the received response channel, and selects a beam in which the terminal has received the control channel as a beam for the terminal. Can be controlled to do. In this case, the control channel may be an Enhanced Physical Downlink Control Channel (EPDCCH) based on a terminal-specific reference signal. In addition, at this time, the response channel may be determined based on a set of control channels received by the terminal.

The controller 1630 may select one of all beams used for transmission of the control channel set and control to transmit a terminal-specific reference signal and a data channel.

In addition, the control unit 1630 allocates a plurality of control channels including the same downlink control information to different control channel candidate regions, allocates different terminal-specific reference signals to each of the control channels, and It is possible to control to apply different antenna gains to a control channel arranged in the candidate region and a reference signal dedicated to each terminal, and to transmit each control channel and a reference signal dedicated to the terminal to which the different antenna gains are applied using different beams. . In this case, the control channel may be an Enhanced Physical Downlink Control Channel (EPDCCH) based on a terminal-specific reference signal.

In the above, the configuration of the base station 1600 and the operation of each unit have been described. However, the description by dividing the configuration as described above is for convenience of description and does not limit the scope of the present invention. In addition, in addition to the operation of the base station described with reference to FIG. 16, the base station 1600 may perform the operation of the base station described with reference to FIGS.

17 is a diagram illustrating a device of a terminal according to an embodiment of the present invention.

The terminal 1700 may include a transmission/reception unit 1710 and a control unit 1730. The transmission/reception unit 1710 may perform data communication with at least one network node. In an embodiment of the present invention, the transmission/reception unit may receive a downlink channel and transmit an uplink channel.

The controller 1730 may control the overall operation of the terminal 1700. In addition, according to an embodiment of the present invention, the control unit 1730 receives a control channel including downlink control information (DCI) through a plurality of beams formed by the base station. And, receiving a data channel scheduled for the control channel from the base station, and transmitting a response channel for receiving the data channel to the base station based on the received control channel, and based on the response channel Thus, it is possible to control to receive a downlink from the base station through a beam selected by the base station. In this case, the selected beam may be selected based on the resource of the response channel transmitted by the terminal from the base station, the beam through which the terminal received the control signal.

In the above, the configuration of the terminal 1700 and the operation of each unit have been described. However, the description by dividing the configuration as described above is for convenience of description and does not limit the scope of the present invention. In addition, in addition to the operation of the terminal described in FIG. 17, the terminal 1700 may perform the terminal operation described with reference to FIGS. 1 to 15 in each embodiment of the present invention.

In addition, the embodiments disclosed in the present specification and the drawings are merely provided specific examples for easy explanation and understanding of the present invention, and are not intended to limit the scope of the present invention. Therefore, the scope of the present invention should be construed that all changes or modified forms derived based on the technical idea of the present invention in addition to the embodiments disclosed herein are included in the scope of the present invention.

Claims (28)

In a method for selecting a beam of a base station in a wireless communication system,
Transmitting a plurality of control channels including downlink control information (DCI) to a terminal using a plurality of beams;
Transmitting a data channel scheduled with the downlink control information to the terminal;
Identifying a response channel including information indicating whether reception of the data channel is successful among a plurality of response channels for a response to the data channel;
Determining a control channel received by the terminal from among the plurality of control channels based on the resource of the response channel; And
Including the step of selecting at least one beam to be used for the terminal from among the plurality of beams based on the control channel received by the terminal,
The selected at least one beam corresponds to a beam transmitted to the terminal with the control channel received by the terminal,
The resource of the response channel is determined based on an index of a control channel element (CCE) of a control channel received by the terminal. The method of claim 1, wherein transmitting a control channel including the downlink control information comprises:
Arranging the plurality of control channels including the downlink control information in different control channel candidate regions,
And transmitting control channels arranged in the different control channel candidate regions through different beams. The method of claim 2,
And transmitting the same data channel and a common reference signal (CRS) using all beams used for transmission of the plurality of control channels. delete delete The method of claim 1, wherein transmitting the plurality of control channels including the downlink control information comprises:
Arranging the plurality of control channels including the same downlink control information in one control channel candidate region,
Applying different antenna gains to the plurality of control channels, and
And transmitting the plurality of control channels to which the different antenna gains are applied using different beams at different timings. The method of claim 1,
Transmitting a common reference signal (CRS) using all beams used for transmission of the plurality of control channels,
Wherein the data channel is transmitted by selecting one of all beams used for transmission of the plurality of control channels. The method of claim 7,
And determining, by the terminal, a beam on which a control channel has been received, based on ACK/NACK information of the received response channel. The method of claim 1, wherein transmitting a plurality of control channels including the downlink control information comprises:
Arranging a plurality of control channel sets including the same downlink control information in different control channel candidate regions,
Applying different antenna gains to a set of control channels arranged in the different control channel candidate regions, and
Transmitting the set of control channels to which the different antenna gains are applied using different beams,
The plurality of control channels, characterized in that the EPDCCH (Enhanced Physical Downlink Control Channel) based on a terminal-specific reference signal. The method of claim 9,
And transmitting the terminal-specific reference signal and the data channel by selecting one of all beams used for transmission of the control channel set. The method of claim 10, wherein the response channel is determined based on a set of control channels received by the terminal. The method of claim 1, further comprising: allocating the plurality of control channels including the same downlink control information to different control channel candidate regions,
Allocating different terminal-specific reference signals to the plurality of control channels,
The step of applying different antenna gains to a control channel and a terminal-specific reference signal arranged in the different control channel candidate regions,
The plurality of control channels to which the different antenna gains are applied and the terminal-specific reference signals are transmitted using different beams,
The plurality of control channels, characterized in that the EPDCCH (Enhanced Physical Downlink Control Channel) based on a terminal-specific reference signal. In the base station for selecting a beam (beam) used in a wireless communication system,
A transceiver; And
Transmitting a plurality of control channels including downlink control information (DCI, Downlink Control Information) to at least one terminal using a plurality of beams,
Transmitting a data channel scheduled with the downlink control information (scheduled) to the terminal,
Identifying a response channel including information indicating whether reception of the data channel is successful among a plurality of response channels for a response to the data channel,
Determining a control channel received by the terminal among the plurality of control channels based on the resource of the response channel,
A control unit for controlling to select at least one beam to be used for the terminal from among the plurality of beams, based on a control channel received by the terminal,
The selected at least one beam corresponds to a beam transmitted to the terminal with the control channel received by the terminal,
The resource of the response channel is determined based on an index of a control channel element (CCE) of a control channel received by the terminal. The method of claim 13, wherein the control unit,
The plurality of control channels including the downlink control information are arranged in different control channel candidate regions, and control channels arranged in the different control channel candidate regions are transmitted through different beams. Base station. The method of claim 14, wherein the control unit,
A base station, characterized in that controlling to transmit the same data channel and a common reference signal (CRS) using all beams used for transmission of the plurality of control channels. delete delete The method of claim 13, wherein the control unit,
The plurality of control channels including the same downlink control information are arranged in one control channel candidate region, different antenna gains are applied to the control channel, and the control channels to which the different antenna gains are applied are set at different timings. The base station, characterized in that for controlling to transmit using different beams. The method of claim 13, wherein the control unit,
Control to transmit a common reference signal (CRS) using all beams used for transmission of the plurality of control channels,
Wherein the data channel is transmitted by selecting one of all beams used for transmission of the plurality of control channels. The method of claim 19, wherein the control unit,
And controlling the terminal to determine a beam on which a control channel has been received, based on ACK/NACK information of the received response channel. The method of claim 13, wherein the control unit,
A plurality of control channel sets including the same downlink control information are arranged in different control channel candidate regions, different antenna gains are applied to the control channel sets arranged in the different control channel candidate regions, and the different antennas Control to transmit a set of control channels to which a gain is applied using different beams,
The base station, characterized in that the plurality of control channels are EPDCCH (Enhanced Physical Downlink Control Channel) based on a terminal-specific reference signal. The method of claim 21,
A base station, characterized in that, by selecting one of all beams used for transmission of the control channel set, the terminal-specific reference signal and the data channel are transmitted. The base station of claim 22, wherein the response channel is determined based on a set of control channels received by the terminal. The method of claim 13, wherein the control unit,
The plurality of control channels including the same downlink control information are allocated to different control channel candidate regions, different terminal-specific reference signals are allocated to the plurality of control channels, and are arranged in the different control channel candidate regions. Control to apply different antenna gains to the control channel and the terminal-only reference signal,
The control channel to which the different antenna gains are applied and the terminal-specific reference signal are transmitted using different beams,
The base station, characterized in that the plurality of control channels are EPDCCH (Enhanced Physical Downlink Control Channel) based on a terminal-specific reference signal. In the communication method of a terminal in a wireless communication system,
Receiving a control channel including downlink control information (DCI) through a plurality of beams formed by a base station;
Receiving a data channel scheduled through the control channel from the base station;
Transmitting, to the base station, a response channel including information indicating whether reception of the data channel has been successfully received based on the received control channel; And
And receiving a downlink from the base station through a beam selected by the base station based on the response channel,
The control channel received by the terminal among a plurality of control channels is determined based on the resource of the response channel, and the beam selected by the base station corresponds to a beam transmitted to the terminal through the control channel received by the terminal,
The resource of the response channel among a plurality of response channels for response to the data channel is determined based on an index of a control channel element (CCE) of the received control channel. The method of claim 25, wherein the selected beam is selected based on a resource of a response channel transmitted by the terminal in the base station. In the terminal for performing wireless communication,
A transceiver; And
A control channel including downlink control information (DCI) is received through a plurality of beams formed by a base station,
Receiving from the base station a data channel scheduled to the control channel (scheduled),
Based on the received control channel, transmits a response channel including information indicating whether or not the data channel is successfully received to the base station,
And a control unit for controlling to receive a downlink from the base station through a beam selected by the base station based on the response channel,
The control channel received by the terminal among a plurality of control channels is determined based on the resource of the response channel, and the beam selected by the base station corresponds to a beam transmitted to the terminal through the control channel received by the terminal,
The terminal, characterized in that the resource of the response channel among a plurality of response channels for response to the data channel is determined based on an index of a control channel element (CCE) of the received control channel. 28. The terminal of claim 27, wherein the selected beam is selected based on a resource of a response channel transmitted by the terminal in the base station.

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