KR101973776B1 - Method and apparatus for receiving uplink signal - Google Patents

Abstract

Receive an uplink signal that determines whether to use a reception beam group to receive an uplink signal based on a preamble for random access or a CQI received from a terminal or a CQI measured from a reference signal of a terminal by a base station An apparatus and method are provided.

Description

Method and apparatus for receiving uplink signal {METHOD AND APPARATUS FOR RECEIVING UPLINK SIGNAL}

The present disclosure relates to an apparatus and a method for receiving an uplink signal using a reception beam group.

Recently, in order to meet the traffic demand of the continuously increasing wireless communication system, research is being conducted to increase the data rate through bandwidth expansion such as millimeter band. In order to alleviate the propagation path loss due to the propagation characteristics of the millimeter band and to increase the propagation distance of radio waves, a beamforming technique using an array antenna, in which a plurality of antennas are aggregated, is essential. According to the beamforming technique, a base station transmitting multiple beams and a terminal receiving a beam from the base station can gain by concentrating transmission and reception of radio waves in a specific direction. Beamforming techniques include an adaptive beamforming scheme and a fixed beamforming scheme. Due to hardware complexity and operational overhead, a fixed beamforming scheme is primarily considered. The fixed beamforming technique overlaps beams to prevent coverage holes. The overlapping multiple beams have a disadvantage in that system performance is increased by increasing inter-beam interference of a transmission / reception signal.

An apparatus and method for receiving an uplink signal through a receive beam group are provided.

According to one embodiment, an apparatus for receiving an uplink signal is provided. The uplink signal receiving apparatus includes a processor, a memory, and a wireless communication unit, and the processor executes a program stored in a memory to receive a preamble for random access from a plurality of terminals, and an uplink signal among the plurality of terminals. Determining whether to use a reception beam group to receive an uplink signal from the first terminal based on the reception power of the first preamble of the first terminal transmitting the Tx, and based on the determination result, a single beam or reception Receiving an uplink signal using the beam group.

When the processor performs the determining in the uplink signal receiving apparatus, a first RA code corresponding to an index of the first preamble among a plurality of random access (RA) codes in a reception beam in which the first preamble is loaded Measuring a first received power of and comparing the first received power of the first RA code in the receive beam with a second received power of the first RA code of the plurality of RA codes in the other beam; have.

In the uplink signal receiving apparatus, when a processor performs a step of receiving an uplink signal using a single beam or a receiving beam group based on a determination result, a ratio of a first received power and a second received power is preset. If greater than, receiving an uplink signal using a single beam, and if the ratio of the first received power and the second received power is not greater than a preset ratio, receiving the uplink signal using the reception beam group Can be.

The preset ratio in the uplink signal receiving apparatus may be a value indicated by a higher layer.

In the uplink signal receiving apparatus, the reception beam group includes a maximum of M1 beams, and M1 may be two or more natural numbers determined in consideration of the reception maximum ratio combining gain of the array antenna.

According to another embodiment, a method of receiving an uplink signal is provided. The uplink signal receiving method may include receiving a preamble for random access from a plurality of terminals, and receiving the preamble for the random access from a first terminal based on a reception power of a first preamble of a first terminal transmitting an uplink signal among the plurality of terminals. Determining whether to use a reception beam group to receive an uplink signal, and receiving an uplink signal using a single beam or a reception beam group based on the determination result.

The determining of the uplink signal receiving method may include: first reception power of a first RA code corresponding to an index of the first preamble among a plurality of random access (RA) codes in a reception beam on which the first preamble is loaded; And measuring the first received power with a second received power of the first RA code among the plurality of RA codes in the other beam.

Receiving an uplink signal using a single beam or a receiving beam group based on a determination result in the uplink signal receiving method, when the ratio of the first received power and the second received power is greater than a preset ratio, the single beam Receiving an uplink signal by using, and if the ratio of the first received power and the second received power is not greater than the preset ratio, it may include receiving the uplink signal using the receiving beam group.

In the uplink signal receiving method, a preset ratio may be a value indicated by an upper layer.

In the uplink signal reception method, the reception beam group includes a maximum of M1 beams, and M1 may be two or more natural numbers determined in consideration of the reception maximum ratio combining gain of the array antenna.

According to yet another embodiment, an apparatus for receiving an uplink signal is provided. The uplink signal receiving apparatus includes a processor, a memory, and a wireless communication unit, and the processor executes a program stored in the memory to execute the first CQI and the interference beam of the serving beam among the channel quality indicators (CQIs). Determining whether to use a reception beam group to receive an uplink signal from a first terminal among a plurality of terminals based on a comparison result between the second CQIs, and based on the determination result, a single beam or a reception beam group is determined. And receiving an uplink signal.

In the uplink signal receiving apparatus, the processor may further perform a step of receiving the CQI from the first terminal before performing the determining.

In the uplink signal receiving apparatus, the number of CQIs may be M smaller than the number of beams received by the first terminal, and M may be a value indicated by a higher layer.

In the uplink signal receiving apparatus, the processor may further perform a step of receiving a sounding reference signal (SRS) from the first terminal and measuring the CQI from the SRS before performing the determining. have.

In the uplink signal receiving apparatus, when the processor performs a step of receiving an uplink signal using a single beam or a receiving beam group based on a determination result, if the difference between the first CQI and the second CQI is greater than a predetermined value, If the uplink signal is received using a single beam and the difference between the first CQI and the second CQI is not greater than a predetermined value, the uplink signal may be received using the reception beam group.

The predetermined value in the uplink signal receiving apparatus may be a value indicated by a higher layer.

By receiving an uplink signal through a reception beam group including some beams among a plurality of beams for transmitting an uplink signal, reception performance of an uplink signal of a base station can be improved.

1 is a diagram schematically illustrating a millimeter-based mobile communication system according to an embodiment.
2 is a diagram schematically illustrating a downlink transmission and reception method between a base station and a terminal according to an embodiment.
3 is a flowchart schematically illustrating an uplink transmission / reception method between a base station and a terminal according to an embodiment.
4 is a flowchart illustrating a method of determining, by a base station, whether to use a reception beam group using a preamble of an RA procedure according to an embodiment.
5 is a flowchart illustrating a method of determining, by a base station, whether to use a reception beam group using a CQI according to an embodiment.
6 is a block diagram illustrating a wireless communication system according to an exemplary embodiment.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present disclosure. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted for simplicity of explanation, and like reference numerals designate like parts throughout the specification.

Throughout the specification, a terminal includes a mobile station (MS), a mobile terminal (MT), an advanced mobile station (AMS), a high reliability mobile station (HR-MS). ), Subscriber station (SS), portable subscriber station (PSS), access terminal (AT), user equipment (user equipment (UE)), machine type communication device ( MTC device) and the like, and may include all or some functions of MT, MS, AMS, HR-MS, SS, PSS, AT, UE, and the like.

In addition, a base station (BS) may be an advanced base station (ABS), a high reliability base station (HR-BS), a node B (node B), an advanced node B (evolved node B, eNodeB), access point (AP), radio access station (RAS), base transceiver station (BTS), mobile multihop relay (MMR) -BS, relay serving as a base station station (RS), relay node (RN) serving as base station, advanced relay station (ARS) serving as base station, high reliability relay station (HR) serving as base station -RS), small base station (femto BS, home node B (HNB), home eNodeB (HeNB), pico base station (pico BS), macro base station (macro BS), micro base station (micro BS) ), Etc., and all or one of ABS, Node B, eNodeB, AP, RAS, BTS, MMR-BS, RS, RN, ARS, HR-RS, small base station, and the like. It may also include negative functions.

1 is a diagram schematically illustrating a millimeter-based mobile communication system according to an embodiment.

In FIG. 1, the base station 200 provides a service to coverage by transmitting and receiving a plurality of beams using an array antenna. That is, the base station 200 covers the fixed beam area by using a plurality of (N) beams, and the beam areas overlap each other in order to prevent the coverage hole of the service area.

In addition, the terminal 100 performing the fixed beamforming may generate an uplink transmission beam using the beam received from the base station 200. In this case, due to implementation limitations (space and price), the terminal 100 may transmit and receive signals through switching of P (N >> P) fixed beams, unlike the base station 200. Therefore, the shape of the beam transmitted from the terminal 100 has a wider radiation form than the transmission beam of the base station 200. That is, the uplink signal is transmitted through a beam having a wider width than the downlink, and the terminal 100 has a high probability of being located in an overlapping region of the beam of the base station 200.

Meanwhile, in the mobile communication system, all beams are shared for the control channel through which control information requiring high reliability is transmitted in both downlink and uplink, but the channel used for data transmission is independently configured by each beam. In addition, since the base station 200 receives a plurality of beams through the uplink channel, it should be able to combine the received multiple beams. At this time, when the base station 200 receives the data channel in the full beam as in the control channel, the efficiency of resource allocation is reduced, and when the data channel is received in the single beam, the performance of the uplink data channel may be degraded.

2 is a diagram schematically illustrating a downlink transmission and reception method between a base station and a terminal according to an embodiment.

Referring to FIG. 2, in downlink of a time division duplex (TDD) system, the base station 200 transmits a plurality of beams TxB1 to TxBN, and the terminal 100 transmits four fixed beams RxB1. To RxB4). In general, in the mobile communication system, the terminal 100 measures the quality of the downlink channel and reports the measurement result of the downlink channel quality periodically or aperiodically to the base station 200. According to an embodiment, each of the N beams used by the base station 200 includes a beam-specific reference signal, and the terminal 100 measures a channel corresponding to each beam to measure a channel quality indicator (CQI). ) Is fed back to the base station 200. CQI is a value representing a signal to noise ratio (SNR) of a received signal in bits according to a predetermined level. For example, if the received signal's SNR ranges from -3 [dB] to 29 [dB], and the CQI is represented by 5 bits (that is, 2 to ⁵ levels), the SNR range corresponding to one CQI step is 1 [dB]. ]to be. The terminal 100 may feed back the CQIs for the entire K beams, and may feed back the CQIs for some M beams of the N beams in order to reduce overhead of resource allocation.

Referring to FIG. 2, the terminal 100 measures the CQI of the transmission beam corresponding to the reception beam RxB1 and reports the information about the transmission beam having the large CQI to the base station 200. In FIG. 2, the terminal 100 measures and reports the CQI for TxB3, TxB4, TxB5, and TxB6 among the transmission beams of the base station 200 to the base station 200. The UE may feed back the CQIs for the predetermined number of beams to the base station. In this case, the number M of the CQIs fed back to the base station is information included in an uplink control channel and may be defined by a standard.

In the uplink, the terminal 100 transmits an uplink data channel in the same beam as the reception beam RxB1. Accordingly, the beam width of the transmission beam is 90 degrees. The base station 200 may receive a signal through the base beam 200 receiving beam group.

3 is a flowchart schematically illustrating an uplink transmission / reception method between a base station and a terminal according to an embodiment.

Referring to FIG. 3, the base station 200 determines whether to use a reception beam group in uplink in a random access (RA) procedure of the terminal 100 or provides a CQI fed back by the terminal 100. Based on the determination of the use of the reception beam group in the uplink, or by using a sounding reference signal (SRS) received from the terminal 100 to measure the CQI in the uplink based on the measured CQI It is possible to determine whether to use the reception beam group.

First, the base station 200 may determine whether to use the reception beam group by using the preamble transmitted in the RA procedure of the terminal 100. The base station 200 receives a preamble for the RA of the terminal 100 (S110), and transmits an RA response to the terminal 100 (S130). In this case, the base station 200 is based on the received power of the preamble, It may be determined whether the reception beam group is used in the uplink (S120), and an uplink signal may be received through a single beam or the reception beam group (S140).

Alternatively, the base station 200 of the time division duplexing (TDD) system may determine whether to use the reception beam group using the CQI fed back by the terminal 100. When the terminal 100 requests an uplink resource, receives an uplink grant (UL grant), and transmits an uplink signal, the terminal 100 feeds back the CQIs for the M beams to the base station 200. (S210). The base station 200 determines whether to use a reception beam group based on the CQI for each beam received from the terminal 100 (S220), and may receive an uplink signal through a single beam or a reception beam group ( S230).

Alternatively, the base station 200 of the frequency division duplexing (FDD) system may determine whether to use the reception beam group in the uplink based on the CQI measured using the SRS received from the terminal 100. The base station 200 receives the SRS of the terminal 100 (S310), and measures the CQI using the received SRS (S320). Thereafter, the base station 200 may determine whether to use the reception beam group in the uplink based on the measured CQI (S330), and receive the uplink signal through the single beam or the reception beam group (S340).

Hereinafter, a method of determining whether a base station 200 uses a reception beam group in uplink will be described in detail with reference to FIGS. 4 to 6.

4 is a flowchart illustrating a method of determining, by a base station, whether to use a reception beam group using a preamble of an RA procedure according to an embodiment.

Referring to FIG. 4, when the plurality of terminals 100 transmit the RA preamble, the base station 200 detects the preamble (S410). Thereafter, the base station 200 measures the reception power of the RA code corresponding to the index of the detected preamble among the plurality of RA codes in the reception beam in which the detected preamble is loaded (S420). Then, the received power of the measured RA code is compared with the received power of the RA code corresponding to the index of the detected preamble among the plurality of RA codes in another beam (S430).

The base station 200 according to an embodiment receives an uplink signal using a single beam when the difference between the received power of the RA code in the reception beam and the received power of the RA code in the other beam is large (S440). However, if the difference between the received power of the RA code in the receive beam and the received power of the RA code in the other beam is small, the uplink signal is received using the receive beam group (S450). At this time, a criterion for determining the magnitude of the difference in the received powers may be set in advance, and for example, a preset ratio between the received powers may be indicated by the upper layer at the initial setting of the base station. For example, if the ratio of the received power of the RA code in the receive beam to the received power of the RA code in the other beam is not greater than a preset value, the base station receives the uplink signal using the receive beam group, and the RA in the receive beam. If the ratio of the received power of the code to the received power of the RA code in the other beam is greater than a preset value, the base station may receive the uplink signal using a single beam.

Meanwhile, when the base station 200 uses the reception beam group to receive the uplink signal, the base station 200 may select one reception beam group among the plurality of reception beam groups. Table 1 below shows the reception beam group and the beam index included in the reception beam group selected by the base station 200.

Receive Beam Group # 0 Beam # 0, beam # 1, ... (up to M1) … … Receive Beam Group # L-1 Beam # 0, beam # 2, ..., (up to M1)

Referring to Table 1, each receive beam group may include at most M1 beams, each receive beam group may include different beams, and M1 may be indicated by a higher layer at the initial configuration of a base station. have. Meanwhile, the base station 200 may select the reception beam group by determining the reception antenna group in the antenna array. In this case, when six or more antennas are included in the receiving antenna group, the maximum number of antennas included in the receiving antenna group may be limited to six, by using a relatively small increase in the maximum reception coupling gain. In this case, the maximum number M1 of beams included in the reception beam group and the maximum number of antennas included in the reception antenna group may be the same.

5 is a flowchart illustrating a method of determining whether to use a reception beam group by a base station 200 using a CQI according to an embodiment.

The base station 200 of the TDD system may receive the CQI reported periodically from the terminal 100 and determine whether to use the reception beam group based on the received CQI. In this case, the number M of beams corresponding to the CQI fed back to the base station by the terminal 100 is preset according to the specification and is larger than the number M1 of the beams included in the reception beam group (that is, M≥M1). Alternatively, the base station 200 of the FDD system may measure the CQI using the SRS received from the terminal 100 and determine whether to use the reception beam group based on the measured CQI.

Referring to FIG. 5, the base station 200 of the TDD system receives the CQI from the terminal 100, and the base station 200 of the FDD system measures the CQI from the SRS transmitted by the terminal 100 (S510).

Thereafter, the base station 200 compares the CQI corresponding to the serving beam with the CQI corresponding to the interference beam (S520). If the difference between the CQI of the serving beam and the CQI of the interference beam is greater than a predetermined value, the base station 200 receives an uplink signal through one reception beam (using a single beam) (S530). However, if the difference between the CQI corresponding to the serving beam and the CQI corresponding to the interference beam is not greater than a predetermined value, the base station 200 receives an uplink signal through the reception beam group (using the reception beam group) (S540). . The CQI of the serving beam and the CQI of the interference beam may be measured to have similar sizes when the terminal 100 is located at the beam boundary region of the base station 200. For example, if the difference between the CQI corresponding to the serving beam and the CQI corresponding to the interfering beam is less than or equal to the preset Q (ie, if the level difference of the CQI is smaller than Q steps), the base station 200 uses the reception beam group. To receive the uplink signal. In this case, the preset Q value may be indicated by the upper layer at the initial setting of the base station.

6 is a block diagram illustrating a wireless communication system according to an exemplary embodiment.

Referring to FIG. 6, a wireless communication system according to an embodiment includes a base station 610 and a terminal 620.

The base station 610 includes a processor 611, a memory 612, and a radio frequency unit (RF unit) 613. The memory 612 may be connected to the processor 611 to store various information for driving the processor 611 or at least one program executed by the processor 611. The wireless communication unit 613 may be connected to the processor 611 to transmit and receive a wireless signal. The processor 611 may implement a function, process, or method proposed in the embodiment of the present disclosure. In this case, in the wireless communication system according to the exemplary embodiment of the present disclosure, the air interface protocol layer may be implemented by the processor 611. An operation of the base station 610 according to an embodiment may be implemented by the processor 611.

The terminal 620 includes a processor 621, a memory 622, and a wireless communication unit 623. The memory 622 may be connected to the processor 621 to store various information for driving the processor 621 or at least one program executed by the processor 621. The wireless communication unit 623 may be connected to the processor 621 to transmit and receive a wireless signal. The processor 621 may implement the functions, steps, or methods proposed in the embodiments of the present disclosure. In this case, in the wireless communication system according to an exemplary embodiment of the present disclosure, the air interface protocol layer may be implemented by the processor 621. The operation of the terminal 620 according to an embodiment may be implemented by the processor 621.

In an embodiment of the present disclosure, the memory may be located inside or outside the processor, and the memory may be connected to the processor through various known means. The memory is various types of volatile or nonvolatile storage media, and for example, the memory may include read-only memory (ROM) or random access memory (RAM).

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

Claims (16)

An apparatus for receiving an uplink signal,
Processor, Memory, and Wireless Communications
Including,
The processor executes a program stored in the memory,
Receiving a preamble for random access from a plurality of terminals through the wireless communication unit,
When a first preamble from the first terminal to transmit the uplink signal among the plurality of terminals is received through a plurality of beams, a comparison result between reception powers of random access (RA) codes in the plurality of beams Determining whether to use a reception beam group to receive the uplink signal from the first terminal based on
Receiving the uplink signal using the single beam or the reception beam group through the wireless communication unit based on the determination result
Device for receiving an uplink signal. In claim 1,
When the processor performs the determining step,
Measuring a first received power of the RA code in a first beam of the plurality of beams loaded with the first preamble, and
Comparing the first received power with a second received power of the RA code in another one of the plurality of beams
Uplink signal receiving apparatus for performing. In claim 2,
When the processor receives the uplink signal using a single beam or the received beam group based on a determination result,
If the ratio of the first received power and the second received power is greater than a preset ratio, the uplink signal is received using the single beam, and the ratio of the first received power and the second received power is the preset ratio. Receiving the uplink signal using the reception beam group if not greater than a set ratio
Uplink signal receiving apparatus for performing. In claim 3,
And the preset ratio is a value indicated by a higher layer. In claim 1,
The receiving beam group includes a maximum of M1 beams, wherein M1 is at least two natural numbers determined in consideration of the reception maximum ratio combining gain of the array antenna. A method for receiving an uplink signal,
Receiving a preamble for random access from a plurality of terminals;
When a first preamble from the first terminal to transmit the uplink signal among the plurality of terminals is received through a plurality of beams, a comparison result between reception powers of random access (RA) codes in the plurality of beams Determining whether to use a reception beam group to receive the uplink signal from the first terminal based on
Receiving the uplink signal using a single beam or the received beam group based on a determination result
Uplink signal receiving method comprising a. In claim 6,
The determining step,
Measuring a first received power of the RA code in a first beam of the plurality of beams loaded with the first preamble, and
Comparing the first received power with a second received power of the RA code in another one of the plurality of beams
The method for receiving an uplink signal. In claim 7,
Receiving the uplink signal using a single beam or the reception beam group based on the determination result,
If the ratio of the first received power and the second received power is greater than a preset ratio, the uplink signal is received using the single beam, and the ratio of the first received power and the second received power is the preset ratio. Receiving the uplink signal using the reception beam group if not greater than a set ratio
The uplink signal receiving method comprising a. In claim 8,
And the preset ratio is a value indicated by a higher layer. In claim 6,
The receiving beam group includes a maximum of M1 beams, wherein M1 is at least two natural numbers determined in consideration of the reception maximum ratio combining gain of the array antenna. An apparatus for receiving an uplink signal,
Processor, Memory, and Wireless Communications
Including,
The processor executes a program stored in the memory,
A first of the plurality of terminals based on a comparison result between a first CQI of a serving beam and a second CQI of an interference beam among a plurality of channel quality indicators (CQIs) measured from channels between the base station and the plurality of terminals; Determining whether to use a reception beam group to receive an uplink signal from a terminal, and
Receiving the uplink signal using a single beam or the received beam group based on a determination result
And then
The receiving beam group includes a maximum of M1 beams, wherein M1 is at least two natural numbers determined in consideration of the reception maximum ratio combining gain of the array antenna. In claim 11,
Before the processor performs the determining step,
Receiving the plurality of CQIs from the first terminal
Further performing, uplink signal receiving apparatus. In claim 12,
The number of the plurality of CQI is M smaller than the number of beams received by the first terminal, wherein M is a value indicated by a higher layer, uplink signal receiving apparatus. In claim 11,
Before the processor performs the determining step,
Receiving a sounding reference signal (SRS) from the first terminal, and
Measuring the plurality of CQIs from the SRS
Further performing, uplink signal receiving apparatus. In claim 11,
When the processor receives the uplink signal using a single beam or the received beam group based on a determination result,
If the difference between the first CQI and the second CQI is greater than a predetermined value, the uplink signal is received using the single beam, and if the difference between the first CQI and the second CQI is not greater than a predetermined value. Receiving the uplink signal using the reception beam group
Uplink signal receiving apparatus for performing. The method of claim 15,
And the predetermined value is a value indicated by a higher layer.

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