KR102155204B1 - Group Based Beam Reporting Method and Apparatus using Uncorrelated Beam on 5G mobile communication - Google Patents

Abstract

In the present specification, among beams of a specific signal received from a base station or a downlink physical channel, M*N beams having a large RSRP compared to a reference signal (M and N are natural numbers greater than 0) are selected and grouped. Group-based beam reporting method and apparatus of a terminal comprising the step of grouping spatially uncorrelated beams into N groups and reporting signal strength information relative to a reference signal for N groups to the base station. to provide.

Description

Group Based Beam Reporting Method and Apparatus using Uncorrelated Beam on 5G mobile communication

The present disclosure relates to a group-based beam reporting method using a spatially uncorrelated uncorrelated beam in 5G mobile communication.

There are demands for large-capacity data processing, high-speed data processing, and various service demands using wireless terminals in vehicles and industrial sites. As described above, there is a need for a technology for a high-speed and large-capacity communication system capable of processing various scenarios and large-capacity data, such as video, wireless data, and machine-type communication data, beyond simple voice-oriented services.

To this end, ITU-R discloses the requirements for adopting the IMT-2020 international standard, and research on next-generation wireless communication technology to meet the requirements of IMT-2020 is in progress.

In particular, 3GPP is conducting research on the LTE-Advanced Pro Rel-15/16 standard and the NR (New Radio Access Technology) standard in parallel to satisfy the IMT-2020 requirements referred to as 5G technology. It plans to receive approval as the next generation wireless communication technology.

The present embodiments provide a group-based beam reporting method and apparatus using an uncorrelated beam in 5G mobile communication to ensure diversity and reduce communication failures due to blockage.

An embodiment provides a group-based beam reporting method of a terminal. The group-based beam reporting method of this terminal includes M*N (M and N are natural numbers greater than 0) beams having a high signal strength (RSRP) compared to a reference signal among the beams of a specific signal or downlink physical channel received from the base station. Selecting and grouping, but grouping spatially uncorrelated beams into N groups, and reporting signal strength information versus reference signals for the N groups to the base station.

Another embodiment provides a receiving method in which a base station receives a group-based beam report. The receiving method of the base station receiving a group-based beam report includes transmitting a specific signal or a downlink physical channel to the terminal, and M* having a large RSRP versus a reference signal among beams of a specific signal or downlink physical channel. Select and group N beams (M and N are natural numbers greater than 0), but receive signal strength information versus reference signals for N groups that group spatially uncorrelated beams into groups. It includes the step of.

Another embodiment provides a terminal that performs group-based beam reporting. The UE performing this group-based beam reporting includes M*N (M and N are natural numbers greater than 0) beams having a greater signal strength (RSRP) compared to a reference signal among beams of a specific signal or downlink physical channel received from the base station. And a control unit for selecting and grouping them, but grouping spatially uncorrelated beams into N groups, and a transmission unit for reporting signal strength information versus reference signals for the N groups to the base station.

The group-based beam reporting method and apparatus using an uncorrelated beam in 5G mobile communication according to the present embodiments can secure diversity and reduce communication failures due to blockage.

1 is a diagram schematically illustrating a structure of an NR wireless communication system to which the present embodiment can be applied.
2 is a diagram for explaining a frame structure in an NR system to which this embodiment can be applied.
3 is a diagram illustrating a resource grid supported by a radio access technology to which the present embodiment can be applied.
4 is a diagram for explaining a bandwidth part supported by a wireless access technology to which the present embodiment can be applied.
5 is a diagram illustrating a synchronization signal block in a wireless access technology to which the present embodiment can be applied.
6 is a diagram for explaining a random access procedure in a radio access technology to which the present embodiment can be applied.
7 is a diagram for explaining CORESET.
8 is a diagram illustrating a conventional DMRS structure for a sidelink and a DMRS structure for a sidelink to which the present embodiment can be applied.
9 is a diagram for explaining various scenarios for V2X communication.
10 illustrates an example of a terminal 1 (UE1) and a terminal 2 (UE2) performing sidelink communication, and a sidelink resource pool used by the terminal 1 (UE1) and terminal 2 (UE2).
11 illustrates the type of a V2X transmission resource pool.
12 shows a method for performing SPS activation (request), reactivation (re-request) and/or release, change triggered by the UE.
13 shows the SA period.
14 shows measured RSRP of base station transmission beams.
15 shows the results of different beam selections.
16 to 20 illustrate examples of group-based beam reporting using a spatially uncorrelated uncorrelated beam beam in 5G mobile communication.
22 is a flowchart of a group-based beam reporting method of a terminal according to another embodiment.
23 is a flowchart of a receiving method in which a base station receives a group-based beam report according to another embodiment.
24 is a diagram showing a configuration of a base station 1000 according to another embodiment.
25 is a diagram showing a configuration of a user terminal 1100 according to another embodiment.

Hereinafter, some embodiments of the present technical idea will be described in detail with reference to exemplary drawings. In adding reference numerals to elements of each drawing, the same elements may have the same numerals as possible even if they are indicated on different drawings. In addition, in describing the technical idea, when it is determined that a detailed description of a related known configuration or function may obscure the gist of the technical idea, the detailed description may be omitted.

In addition, terms such as first, second, A, B, (a), and (b) may be used in describing the components of the present embodiments. These terms are only for distinguishing the component from other components, and the nature, order, order, or number of the component is not limited by the term. When a component is described as being "connected", "coupled" or "connected" to another component, the component may be directly connected or connected to that other component, but other components between each component It is to be understood that is "interposed", or that each component may be "connected", "coupled" or "connected" through other components.

In addition, terms and technical names used in the present specification are for describing specific embodiments, and the technical idea is not limited thereto. The terms described below may be interpreted as meanings generally understood by those of ordinary skill in the technical field to which the present technical idea belongs unless otherwise defined. When the corresponding term is an incorrect technical term that does not accurately express the present technical idea, it will be replaced with a technical term that can be correctly understood by those skilled in the art to be understood. In addition, general terms used in the present specification should be interpreted as defined in the dictionary or according to the context before and after, and should not be interpreted as an excessively reduced meaning.

The wireless communication system in the present specification refers to a system for providing various communication services such as voice and data packets using radio resources, and may include a terminal, a base station, and a core network.

The embodiments disclosed below can be applied to a wireless communication system using various wireless access technologies. For example, the present embodiments include code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple (SC-FDMA). access) can be applied to various wireless access technologies. CDMA may be implemented with a radio technology such as universal terrestrial radio access (UTRA) or CDMA2000. TDMA may be implemented with a radio technology such as global system for mobile communications (GSM)/general packet radio service (GPRS)/enhanced data rates for GSM evolution (EDGE). OFDMA may be implemented with wireless technologies such as IEEE (institute of electrical and electronics engineers) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, and E-UTRA (evolved UTRA). IEEE 802.16m is an evolution of IEEE 802.16e and provides backward compatibility with a system based on IEEE 802.16e. UTRA is part of a universal mobile telecommunications system (UMTS). 3rd generation partnership project (3GPP) long term evolution (LTE) is a part of evolved UMTS (E-UMTS) that uses evolved-UMTS terrestrial radio access (E-UTRA), and employs OFDMA in downlink and SC in uplink. -Adopt FDMA. As described above, the present embodiments may be applied to a wireless access technology currently disclosed or commercialized, and may be applied to a wireless access technology currently being developed or to be developed in the future.

Meanwhile, a terminal in the present specification is a generic concept that refers to a device including a wireless communication module that performs communication with a base station in a wireless communication system, and is a UE in WCDMA, LTE, HSPA, and IMT-2020 (5G or New Radio). In addition to (User Equipment), it should be interpreted as a concept that includes all of MS (Mobile Station), UT (User Terminal), SS (Subscriber Station), and wireless device in GSM. In addition, the terminal may be a user's portable device such as a smart phone according to the usage type, and in the V2X communication system, it may mean a vehicle, a device including a wireless communication module in the vehicle, and the like. In addition, in the case of a machine type communication system, it may mean an MTC terminal or an M2M terminal equipped with a communication module so that machine type communication is performed.

The base station or cell of the present specification refers to the end of communication with the terminal in terms of the network, and Node-B (Node-B), eNB (evolved Node-B), gNB (gNode-B), LPN (Low Power Node), Sector, Site, various types of antennas, BTS (Base Transceiver System), Access Point, Point (e.g., Transmit Point, Receiving Point, Transmitting Point), Relay Node ), a mega cell, a macro cell, a micro cell, a pico cell, a femto cell, a remote radio head (RRH), a radio unit (RU), and a small cell.

In the various cells listed above, since there is a base station controlling each cell, the base station can be interpreted in two meanings. 1) In relation to the radio area, the device itself may provide a mega cell, a macro cell, a micro cell, a pico cell, a femto cell, and a small cell, or 2) the radio area itself may be indicated. In 1), all devices that are controlled by the same entity that provide a predetermined wireless area are controlled by the same entity, or all devices that interact to form a wireless area in collaboration are instructed to the base station. A point, a transmission/reception point, a transmission point, a reception point, etc. may be an embodiment of a base station according to the configuration method of the wireless area. In 2), it is possible to instruct the base station to the radio region itself that receives or transmits a signal from the viewpoint of the user terminal or the viewpoint of a neighboring base station.

In the present specification, a cell refers to a component carrier having coverage of a signal transmitted from a transmission/reception point or a coverage of a signal transmitted from a transmission/reception point, and the transmission/reception point itself. I can.

Uplink (Uplink, UL, or uplink) refers to a method of transmitting and receiving data to a base station by a UE, and downlink (Downlink, DL, or downlink) refers to a method of transmitting and receiving data to a UE by a base station. do. Downlink may refer to a communication or communication path from multiple transmission/reception points to a terminal, and uplink may refer to a communication or communication path from a terminal to multiple transmission/reception points. In this case, in the downlink, the transmitter may be a part of multiple transmission/reception points, and the receiver may be a part of the terminal. In addition, in the uplink, the transmitter may be a part of the terminal, and the receiver may be a part of the multiple transmission/reception points.

Uplink and downlink transmit and receive control information through a control channel such as Physical Downlink Control CHannel (PDCCH), Physical Uplink Control CHannel (PUCCH), and the like, and The same data channel is configured to transmit and receive data. Hereinafter, a situation in which signals are transmitted/received through channels such as PUCCH, PUSCH, PDCCH, and PDSCH may be expressed in the form of “transmitting and receiving PUCCH, PUSCH, PDCCH, and PDSCH”.

In order to clarify the description, hereinafter, the present technical idea is mainly described with respect to a 3GPP LTE/LTE-A/NR (New RAT) communication system, but the present technical feature is not limited thereto.

After research on 4G (4th-Generation) communication technology, 3GPP is conducting research on 5G (5th-Generation) communication technology to meet the requirements of ITU-R's next-generation wireless access technology. Specifically, 3GPP is conducting research on LTE-A pro, which has improved LTE-Advanced technology as a 5G communication technology in accordance with the requirements of ITU-R, and a new NR communication technology separate from 4G communication technology. It is expected that both LTE-A pro and NR will be submitted as 5G communication technology, but in the following, for convenience of explanation, these embodiments will be described focusing on NR.

The operation scenario in NR defined various operation scenarios by adding considerations to satellites, automobiles, and new verticals from the existing 4G LTE scenario.In terms of service, eMBB (Enhanced Mobile Broadband) scenario, high terminal density, but wide It is deployed in the range and supports the mMTC (Massive Machine Communication) scenario that requires a low data rate and asynchronous connection, and the URLLC (Ultra Reliability and Low Latency) scenario that requires high responsiveness and reliability and supports high-speed mobility. .

In order to satisfy this scenario, NR discloses a wireless communication system to which a new waveform and frame structure technology, a low latency technology, a mmWave support technology, and a forward compatible provision technology are applied. In particular, in the NR system, various technical changes are proposed in terms of flexibility to provide forward compatibility. Main technical features will be described below with reference to the drawings.

<NR system general>

1 is a diagram schematically showing a structure of an NR system to which this embodiment can be applied.

1, the NR system is divided into 5GC (5G Core Network) and NR-RAN parts, and the NG-RAN controls the user plane (SDAP/PDCP/RLC/MAC/PHY) and UE (User Equipment). It consists of gNBs and ng-eNBs that provide plane (RRC) protocol termination. The gNB mutually or the gNB and the ng-eNB are interconnected through the Xn interface. The gNB and ng-eNB are each connected to 5GC through the NG interface. The 5GC may include an Access and Mobility Management Function (AMF) in charge of a control plane such as a terminal access and mobility control function, and a User Plane Function (UPF) in charge of a control function for user data. NR includes support for both frequency bands below 6GHz (FR1, Frequency Range 1) and frequencies above 6GHz (FR2, Frequency Range 2).

gNB means a base station that provides NR user plane and control plane protocol termination to a terminal, and ng-eNB means a base station that provides E-UTRA user plane and control plane protocol termination to a terminal. The base station described in the present specification should be understood in a sense encompassing gNB and ng-eNB, and may be used as a means to distinguish between gNB or ng-eNB as necessary.

<NR wave form, numer roller and frame structure>

In NR, a CP-OFDM waveform using a cyclic prefix is used for downlink transmission, and CP-OFDM or DFT-s-OFDM is used for uplink transmission. OFDM technology is easy to combine with MIMO (Multiple Input Multiple Output), and has the advantage of being able to use a low complexity receiver with high frequency efficiency.

On the other hand, in NR, since the requirements for data rate, delay rate, and coverage are different for each of the three scenarios described above, it is necessary to efficiently satisfy the requirements for each scenario through a frequency band constituting an arbitrary NR system. . To this end, a technique for efficiently multiplexing a plurality of different numerology-based radio resources has been proposed.

값에 따라 지수적으로 변경된다. Specifically, the NR transmission neuron is determined based on sub-carrier spacing and CP (Cyclic prefix), and is based on 15khz as shown in Table 1 below.

It changes exponentially according to the value.

Cyclic prefix Supported for data Supported for synch 0 15 Normal Yes Yes One 30 Normal Yes Yes 2 60 Normal, Extended Yes No 3 120 Normal Yes Yes 4 240 Normal No Yes

As shown in Table 1 above, the NR neuron can be classified into 5 types according to the subcarrier interval. This is different from the fixed subcarrier spacing of 15khz of LTE, one of the 4G communication technologies. Specifically, subcarrier intervals used for data transmission in NR are 15, 30, 60, and 120khz, and subcarrier intervals used for synchronization signal transmission are 15, 30, 12, and 240khz. In addition, the extended CP is applied only to the 60khz subcarrier interval.

Meanwhile, a frame structure in NR is defined as a frame having a length of 10 ms consisting of 10 subframes having the same length of 1 ms. One frame can be divided into 5 ms half frames, and each half frame includes 5 subframes. In the case of the 15khz subcarrier interval, one subframe consists of 1 slot, and each slot consists of 14 OFDM symbols.

2 is a diagram for explaining a frame structure in an NR system to which this embodiment can be applied.

Referring to FIG. 2, in the case of a normal CP, a slot is fixedly composed of 14 OFDM symbols, but the length of the slot may vary according to the subcarrier interval. For example, in the case of a newer roller having a 15khz subcarrier interval, a slot is 1ms long and has the same length as the subframe. In contrast, in the case of a newer roller with a 30khz subcarrier spacing, a slot consists of 14 OFDM symbols, but two slots may be included in one subframe with a length of 0.5ms. That is, the subframe and the frame are defined with a fixed time length, and the slot is defined by the number of symbols, and the time length may vary according to the subcarrier interval.

Meanwhile, NR defines a basic unit of scheduling as a slot, and introduces a mini-slot (or sub-slot or non-slot based schedule) in order to reduce the transmission delay of the radio section. If a wide subcarrier spacing is used, the length of one slot is shortened in inverse proportion, so that transmission delay in the radio section can be reduced. The mini-slot (or sub-slot) is for efficient support for the URLLC scenario, and scheduling is possible in units of 2, 4, or 7 symbols.

In addition, unlike LTE, NR defines uplink and downlink resource allocation as a symbol level within one slot. In order to reduce HARQ delay, a slot structure capable of transmitting HARQ ACK/NACK directly within a transmission slot has been defined, and this slot structure is named and described as a self-contained structure.

NR is designed to support a total of 256 slot formats, of which 62 slot formats are used in Rel-15. In addition, a common frame structure constituting an FDD or TDD frame is supported through a combination of various slots. For example, a slot structure in which all symbols of a slot are set to downlink, a slot structure in which all symbols are set to uplink, and a slot structure in which a downlink symbol and an uplink symbol are combined are supported. In addition, NR supports that data transmission is distributed and scheduled in one or more slots. Accordingly, the base station may inform the UE of whether the slot is a downlink slot, an uplink slot, or a flexible slot using a slot format indicator (SFI). The base station can indicate the slot format by indicating the index of the table configured through RRC signaling specifically through the UE, using SFI, and dynamically indicate through Downlink Control Information (DCI) or statically or semi-statically through RRC. May be.

<NR physical resource>

Regarding the physical resource in NR, the antenna port, resource grid, resource element, resource block, bandwidth part, etc. are considered. Can be.

The antenna port is defined so that a channel carrying a symbol on an antenna port can be inferred from a channel carrying another symbol on the same antenna port. When the large-scale property of a channel carrying a symbol on one antenna port can be inferred from a channel carrying a symbol on another antenna port, the two antenna ports are QC/QCL (quasi co-located or quasi co-location) relationship. Here, the wide-range characteristic includes one or more of delay spread, Doppler spread, frequency shift, average received power, and received timing.

3 is a diagram illustrating a resource grid supported by a radio access technology to which the present embodiment can be applied.

Referring to FIG. 3, since the NR supports a plurality of neurons in the same carrier, a resource grid may exist according to each neuron in the resource grid. In addition, the resource grid may exist according to an antenna port, a subcarrier spacing, and a transmission direction.

A resource block consists of 12 subcarriers, and is defined only in the frequency domain. In addition, a resource element consists of one OFDM symbol and one subcarrier. Accordingly, as shown in FIG. 3, the size of one resource block may vary according to the subcarrier interval. In addition, NR defines “Point A” that serves as a common reference point for the resource block grid, a common resource block, and a virtual resource block.

4 is a diagram for explaining a bandwidth part supported by a wireless access technology to which the present embodiment can be applied.

In NR, unlike LTE where the carrier bandwidth is fixed at 20Mhz, the maximum carrier bandwidth is set from 50Mhz to 400Mhz for each subcarrier interval. Therefore, it is not assumed that all terminals use all of these carrier bandwidths. Accordingly, in the NR, as shown in FIG. 4, the terminal can use the bandwidth part by designating the bandwidth part within the carrier bandwidth. In addition, the bandwidth part is associated with one neurology and is composed of a subset of consecutive common resource blocks, and can be dynamically activated over time. The UE is configured with up to four bandwidth parts, respectively, in uplink and downlink, and data is transmitted and received using the active bandwidth part at a given time.

In the case of a paired spectrum, uplink and downlink bandwidth parts are independently set, and in the case of an unpaired spectrum, unnecessary frequency re-tuning between downlink and uplink operations is prevented. For this purpose, the downlink and uplink bandwidth parts are set in pairs to share a center frequency.

<NR initial connection>

In NR, the terminal accesses the base station and performs cell search and random access procedures to perform communication.

Cell search is a procedure in which a terminal synchronizes with a cell of a corresponding base station, obtains a physical layer cell ID, and obtains system information by using a synchronization signal block (SSB) transmitted by a base station.

5 is a diagram illustrating a synchronization signal block in a wireless access technology to which the present embodiment can be applied.

Referring to FIG. 5, the SSB is composed of a primary synchronization signal (PSS) and secondary synchronization signal (SSS) occupying 1 symbol and 127 subcarriers, respectively, and a PBCH spanning 3 OFDM symbols and 240 subcarriers. .

The terminal receives the SSB by monitoring the SSB in the time and frequency domain.

SSB can be transmitted up to 64 times in 5ms. A plurality of SSBs are transmitted in different transmission beams within 5 ms time, and the UE performs detection on the assumption that SSBs are transmitted every 20 ms period based on one specific beam used for transmission. The number of beams that can be used for SSB transmission within 5 ms time may increase as the frequency band increases. For example, up to 4 SSB beams can be transmitted under 3GHz, and up to 8 in a frequency band of 3 to 6GHz, and a maximum of 64 different beams in a frequency band of 6GHz or higher can be used to transmit SSBs.

Two SSBs are included in one slot, and the start symbol and the number of repetitions in the slot are determined according to the subcarrier interval as follows.

-Case A-15 kHz subcarrier spacing: the first symbols of the candidate SS/PBCH blocks have indexes of {2, 8} + 14*n. For carrier frequencies smaller than or equal to 3 GHz, n=0, 1. For carrier frequencies larger than 3 GHz and smaller than or equal to 6 GHz, n=0, 1, 2, 3.

-Case B-30 kHz subcarrier spacing: the first symbols of the candidate SS/PBCH blocks have indexes {4, 8, 16, 20} + 28*n. For carrier frequencies smaller than or equal to 3 GHz, n=0. For carrier frequencies larger than 3 GHz and smaller than or equal to 6 GHz, n=0, 1.

-Case C-30 kHz subcarrier spacing: the first symbols of the candidate SS/PBCH blocks have indexes {2, 8} + 14*n. For carrier frequencies smaller than or equal to 3 GHz, n=0, 1. For carrier frequencies larger than 3 GHz and smaller than or equal to 6 GHz, n=0, 1, 2, 3.

-Case D-120 kHz subcarrier spacing: the first symbols of the candidate SS/PBCH blocks have indexes {4, 8, 16, 20} + 28*n. For carrier frequencies larger than 6 GHz, n=0, 1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 15, 16, 17, 18.

-Case E-240 kHz subcarrier spacing: the first symbols of the candidate SS/PBCH blocks have indexes {8, 12, 16, 20, 32, 36, 40, 44} + 56*n. For carrier frequencies larger than 6 GHz, n=0, 1, 2, 3, 5, 6, 7, 8.

Meanwhile, the SSB is not transmitted at the center frequency of the carrier bandwidth, unlike the conventional LTE SS. That is, the SSB may be transmitted even in a place other than the center of the system band, and a plurality of SSBs may be transmitted in the frequency domain when broadband operation is supported. Accordingly, the UE monitors the SSB by using a synchronization raster, which is a candidate frequency location for monitoring the SSB. The carrier raster and synchronization raster, which are information on the center frequency of the channel for initial access, are newly defined in NR, and the synchronization raster has a wider frequency interval than the carrier raster, so it supports fast SSB search of the terminal. I can.

The UE can acquire the MIB through the PBCH of the SSB. The MIB (Master Information Block) includes minimum information for the terminal to receive remaining system information (RMSI, Remaining Minimum System Information) broadcast by the network. In addition, PBCH is information about the location of the first DM-RS symbol in the time domain, information for the UE to monitor SIB1 (e.g., SIB1 neurology information, information related to SIB1 CORESET, search space information, PDCCH Related parameter information, etc.), offset information between the common resource block and the SSB (the position of the absolute SSB in the carrier is transmitted through SIB1), and the like. Here, the SIB1 neurology information is equally applied to messages 2 and 4 of the random access procedure for accessing the base station after the terminal completes the cell search procedure.

The aforementioned RMSI means SIB1 (System Information Block 1), and SIB1 is broadcast periodically (ex, 160 ms) in a cell. SIB1 includes information necessary for the UE to perform an initial random access procedure, and is periodically transmitted through the PDSCH. In order for the UE to receive SIB1, it is necessary to receive newer roller information used for SIB1 transmission and CORESET (Control Resource Set) information used for SIB1 scheduling through the PBCH. The UE checks scheduling information for SIB1 using SI-RNTI in CORESET, and acquires SIB1 on the PDSCH according to the scheduling information. SIBs other than SIB1 may be periodically transmitted or may be transmitted according to the request of the terminal.

6 is a diagram for explaining a random access procedure in a radio access technology to which the present embodiment can be applied.

Referring to FIG. 6, when the cell search is completed, the UE transmits a random access preamble for random access to the base station. The random access preamble is transmitted through the PRACH. Specifically, the random access preamble is transmitted to the base station through a PRACH consisting of consecutive radio resources in a specific slot that is periodically repeated. In general, when a terminal initially accesses a cell, a contention-based random access procedure is performed, and when a random access is performed for beam failure recovery (BFR), a contention-free random access procedure is performed.

The terminal receives a random access response to the transmitted random access preamble. The random access response may include a random access preamble identifier (ID), UL Grant (uplink radio resource), temporary C-RNTI (Temporary Cell-Radio Network Temporary Identifier), and TAC (Time Alignment Command). Since one random access response may include random access response information for one or more terminals, the random access preamble identifier may be included to inform which terminal the included UL Grant, temporary C-RNTI, and TAC are valid. The random access preamble identifier may be an identifier for a random access preamble received by the base station. TAC may be included as information for the UE to adjust uplink synchronization. The random access response may be indicated by a random access identifier on the PDCCH, that is, a Random Access-Radio Network Temporary Identifier (RA-RNTI).

Upon receiving a valid random access response, the terminal processes the information included in the random access response and performs scheduled transmission to the base station. For example, the UE applies TAC and stores a temporary C-RNTI. Also, by using UL Grant, data stored in the buffer of the terminal or newly generated data is transmitted to the base station. In this case, information for identifying the terminal should be included.

Finally, the terminal receives a downlink message for resolving contention.

<NR CORESET>

The downlink control channel in NR is transmitted in CORESET (Control Resource Set) having a length of 1 to 3 symbols, and transmits uplink/downlink scheduling information, SFI (Slot Format Index), and TPC (Transmit Power Control) information. .

In this way, NR introduced the concept of CORESET to secure system flexibility. CORESET (Control Resource Set) means a time-frequency resource for a downlink control signal. The terminal may decode the control channel candidate using one or more search spaces in the CORESET time-frequency resource. A QCL (Quasi CoLocation) assumption for each CORESET is set, and this is used to inform the characteristics of the analog beam direction in addition to the delay spread, Doppler spread, Doppler shift, and average delay, which are characteristics assumed by conventional QCL.

7 is a diagram for explaining CORESET.

Referring to FIG. 7, CORESET may exist in various forms within a carrier bandwidth within one slot, and CORESET may consist of up to 3 OFDM symbols in the time domain. In addition, CORESET is defined as a multiple of 6 resource blocks up to the carrier bandwidth in the frequency domain.

The first CORESET is indicated through the MIB as part of the initial bandwidth part configuration so that additional configuration information and system information can be received from the network. After establishing the connection with the base station, the terminal may receive and configure one or more CORESET information through RRC signaling.

<LTE sidelink>

In the existing LTE system, radio channels and radio protocols for direct communication (ie, sidelink) between terminals were designed to provide direct communication between terminals and V2X (especially V2V) services.

Regarding the sidelink, PSSS/SSSS, which is a synchronization signal for synchronization between a wireless sidelink transmitting end and a receiving end, and PSBCH (Physical Sidelink Broadcasting Channel) for transmitting and receiving a related sidelink MIB (Master Information Block) are defined, and discovery information Designs were made for a physical sidelink discovery channel (PSCCH) for transmission and reception, a physical sidelink control channel (PSCCH) for transmission and reception of sidelink control information (SCI), and a physical sidelink shared channel (PSSCH) for transmission and reception of sidelink data.

In addition, for radio resource allocation for a sidelink, a technique was developed by dividing into mode 1 in which the base station allocates radio resources and mode 2 in which the terminal selects and allocates radio resources from a radio resource pool. In addition, the LTE system required additional technological evolution to satisfy the V2X scenario.

In this environment, 3GPP derived 27 service scenarios related to vehicle recognition in Rel-14 and determined major performance requirements according to road conditions. In addition, in recent Rel-15, six performance requirements were determined by deriving 25 more advanced service scenarios such as platoon driving, advanced driving, and long-distance vehicle sensors.

In order to satisfy these performance requirements, the development of a technology to improve the performance of the sidelink technology developed based on the conventional D2D communication according to the requirements of V2X has been progressed. Particularly, in order to apply to C-V2X (Cellular-V2X), technology that improves the physical layer design of the sidelink to be suitable for high-speed environments, resource allocation technology, and synchronization technology can be selected as major research technologies.

The sidelink described below refers to a link used for D2D communication developed after 3GPP Rel-12 and V2X communication after Rel-14, and each channel term, synchronization term, resource term, etc. are D2D communication requirements, V2X Regardless of the Rel-14, 15 requirements, they are described in the same terms. However, for convenience of understanding, the description will focus on the difference between the sidelinks that satisfy the V2X scenario requirements based on the sidelink for D2D communication in Rel-12/13 as needed. Accordingly, terms related to sidelinks to be described below are only to be described by dividing D2D communication/V2X communication/C-V2X communication for convenience of comparison and understanding, and are not limitedly applied to a specific scenario.

<Sidelink Physical Layer Design>

For V2X communication, in order to improve channel estimation performance and frequency offset estimation performance, it is necessary to allocate more pilot signals, demodulation reference signals (DMRS) than D2D communication.

8 is a diagram illustrating a conventional DMRS structure for a sidelink and a DMRS structure for a sidelink to which the present embodiment can be applied.

Referring to FIG. 8, two conventional (Rel-12/13) DMRSs are allocated per subframe of PSCCH, PSSCH, and PSBCH, and the interval between DMRSs is 0.5 ms. The C-V2X terminal uses the 6GHz center frequency band defined for sidelink transmission, and the vehicle terminal moves at 280km/h in consideration of the relative speed. At this time, the correlation time is 0.277 ms, and since this value is shorter than the interval between the reference signals of Rel-12/13, the channel estimation time is insufficient. To solve this problem, in the sidelink for V2X communication, the number of DMRSs per subframe was increased to 4 and the interval between the reference signals was reduced to 0.214ms, so that the design of the physical layer was changed to facilitate channel estimation even with rapid channel changes. .

Meanwhile, one example of a method of selecting a DMRS symbol pattern is that in a dedicated carrier, the PSCCH/PSSCH allocates a DMRS to the 2/5/8/11 OFDM symbol, and the PSBCH is the DMRS to the 3/5/8/10 OFDM symbol. Is assigned. In the 2GHz band, the Rel-12/13 method with two DMRSs can be used as it is. That is, the number and pattern of DMRS transmissions may be differently configured according to the channel and carrier frequency band.

In addition, the TDM (Time Division Multiplexing) scheme used in D2D uses the Frequency Division Multiplexing (FDM) scheme because it is not suitable for C-V2X, where multiple vehicles are concentrated and connected simultaneously.

<Resource allocation>

9 is a diagram for explaining various scenarios for V2X communication.

Referring to FIG. 9, a V2X terminal (denoted as a vehicle, but variously settable such as a user terminal) may be located within the coverage of a base station (eNB or gNB or ng-eNB), or may be located outside the base station coverage. For example, communication may be performed between terminals within the coverage of the base station (UE N-1, UE G-1, and UE X), and between a terminal within the base station coverage and an external terminal (ex, UE N-1, UE N- 2) can also perform communication. Alternatively, communication may be performed between terminals (ex, UE G-1, UE G-2) outside the coverage of the base station.

In these various scenarios, radio resource allocation for communication is required in order for the corresponding terminal to perform communication using the sidelink, and radio resource allocation is largely divided into base station handling allocation and a method of selecting and allocating the terminal itself.

Specifically, in D2D, a method of allocating a resource by a UE includes a centralized method (Mode 1) in which the base station intervenes in resource selection and management, and a distributed method (Mode 2) in which the UE randomly selects a preset resource. Similar to D2D, in C-V2X, there are a method in which a base station intervenes in resource selection and management (Mode 3) and a method in which a vehicle directly selects resources in V2X (Mode 4). In Mode 3, the base station schedules an SA (Scheduling Assignment) pool resource area and a DATA pool resource area allocated thereto to the transmitting terminal.

10 illustrates an example of a terminal 1 (UE1) and a terminal 2 (UE2) performing sidelink communication, and a sidelink resource pool used by the terminal 1 (UE1) and terminal 2 (UE2).

Referring to FIG. 10, the base station is indicated as an eNB, but may be gNB or ng-eNB as described above. In addition, the terminal exemplarily shows a mobile phone, but may be applied in various ways such as a vehicle and an infrastructure device.

In FIG. 10(a), the transmitting terminal UE1 may select a resource unit corresponding to a specific resource in a resource pool, which means a set of resources, and transmit a sidelink signal using the resource unit. The receiving terminal UE2 may receive a resource pool through which UE1 can transmit a signal and detect a transmission signal of the corresponding terminal.

Here, the resource pool may be notified by the base station when UE1 is in the connection range of the base station, and may be notified by another terminal or determined as a predetermined resource when it is outside the connection range of the base station. In general, the resource pool is composed of a plurality of resource units, and each terminal may select one or a plurality of resource units and use it for transmitting its own sidelink signal.

Referring to FIG. 10(b), it can be seen that the total frequency resource is divided into NF and the total time resource is divided into NT, so that a total of NF*NT resource units are defined. Here, it can be said that the corresponding resource pool is repeated at the NT subframe cycle. In particular, one resource unit may appear periodically and repeatedly as shown.

On the other hand, the resource pool can be subdivided into several types. First, it can be classified according to the contents of the sidelink signal transmitted from each resource pool. For example, the content of the sidelink signal may be classified, and a separate resource pool may be configured for each. As the content of the sidelink signal, there may be a scheduling assignment (SA), a sidelink data channel, and a discovery channel.

The SA provides information such as the location of resources used for transmission of the sidelink data channel that the transmitting terminal follows, and information such as modulation and coding scheme (MCS), MIMO transmission method, and timing advance (TA) necessary for demodulation of other data channels. It may be a signal containing. This signal may be multiplexed with sidelink data and transmitted on the same resource unit, and in this case, the SA resource pool may mean a pool of resources transmitted by multiplexing an SA with sidelink data.

On the other hand, the FDM scheme applied to V2X communication can reduce a delay time for data resource allocation after SA resource allocation. For example, a non-adjacent method for separating control channel resources and data channel resources in a time domain within one subframe and an adjacent method for continuously allocating control channels and data channels within one subframe are considered.

Meanwhile, when an SA is multiplexed and transmitted together with sidelink data on the same resource unit, only a sidelink data channel excluding SA information may be transmitted in a resource pool for a sidelink data channel. In other words, resource elements that were used to transmit SA information on individual resource units in the SA resource pool can still be used to transmit sidelink data in the sidelink data channel resource pool. The discovery channel may be a resource pool for a message that enables a transmitting terminal to discover itself by transmitting information such as its ID. Even when the content of the sidelink signal is the same, a different resource pool may be used according to the transmission/reception property of the sidelink signal.

For example, even in the same sidelink data channel or discovery message, a method for determining the transmission timing of a sidelink signal (for example, whether it is transmitted at the time of reception of a synchronization reference signal or transmitted by applying a certain TA there) or a resource allocation method (For example, whether the base station assigns transmission resources of individual signals to individual transmitting terminals or whether individual transmitting terminals select individual signal transmission resources in the pool), signal format (e.g., each sidelink signal is The number of symbols occupied in the frame, the number of subframes used for transmission of one sidelink signal), signal strength from the base station, transmission power strength of the sidelink terminal, etc. may be divided into different resource pools.

V2X resource pool (Sensing and selection windows)

The V2X terminal may perform message (or channel) transmission on a predefined (or signaled) resource pool. Here, the resource pool may mean a resource(s) defined in advance so that the terminal performs a V2X operation (or a V2X operation can be performed). In this case, the resource pool may be defined in terms of, for example, time-frequency. Meanwhile, various types of V2X transmission resource pools may exist.

11 illustrates the type of a V2X transmission resource pool.

Referring to FIG. 11(a), V2X transmission resource pool #A may be a resource pool in which only (partial) sensing is allowed. The V2X transmission resource selected by (partial) sensing is semi-statically maintained at a certain period as shown in FIG. 11(a).

Referring to FIG. 11(b), V2X transmission resource pool #Β may be a resource pool in which only random selection is allowed. In the V2X transmission resource pool #B, the UE may not perform (partial) sensing and may randomly select a V2X transmission resource in a selection window.

Here, as an example, in a resource pool in which only random selection is allowed, unlike a resource pool in which only (partial) sensing is allowed, the selected resource may be set to not be semi-statically reserved (/ signaling). The base station may be configured not to perform a sensing operation (based on scheduling allocation decoding/energy measurement) in order for the terminal to perform a V2X message transmission operation on the V2X transmission resource pool.

Meanwhile, although not shown in FIG. 11, a resource pool capable of both (partial) sensing and random selection may exist. The base station may inform that it can select the V2X resource in either of the partial sensing and the random selection.

V2X UL SPS

In general, UL transmission using SPS may cause a slight delay when the gap between the generation of user data and the configured SPS resource is large. Therefore, when the SPS is used for delay-sensitive traffic such as V2X communication, the SPS scheduling interval must be small enough to support the delay requirement.

However, since the UE may not sufficiently utilize the configured SPS resources, a smaller SPS scheduling interval may incur more overhead. Therefore, the gap between user data generation and the configured SPS resource must be small, and the SPS scheduling interval must be suitable to satisfy the delay requirement. Currently, there is no mechanism to support this function.

12 shows a method for performing SPS activation (request), reactivation (re-request) and/or release, change triggered by the UE.

The UE may receive the SPS configuration for one or more specific logical channels. The UE may receive the SPS configuration for a specific logical channel through system information, RRC connection setup message, RRC connection reconfiguration message, or RRC connection release message.

When data is available for a specific logical channel(s), the UE may request SPS activation to the eNB and then perform UL transmission using the configured SPS resources according to the SPS activation command received from the eNB. The UE may transmit an SPS activation request to the eNB through a physical uplink control channel (PUCCH), a MAC control element (CE), or an RRC message. That is, the UE may transmit the SPS activation request to the eNB by using the control resource used to request the SPS activation. The control resource may be a PUCCH resource, a random access resource, or a new UL control channel resource. In addition, the UE may transmit an SPS activation request to the eNB during, for example, RRC connection (re-) establishment, during handover, after handover, or in RRC_CONNECTED.

Since the UE actively requests SPS activation to the eNB when there is UL data to be transmitted, the gap between the generation of UL data and the configured SPS resources may be reduced.

12, the UE receives SPS configuration information including three SPS configurations from an eNB. If there is UL data to be transmitted from the upper layer, the UE transmits an SPS request message from the eNB through, for example, MAC CE. The eNB sends an Ack message for one of the three SPS configurations. The UE transmits UL data in a specific resource, for example, 1sec cycle according to the SPS configuration.

On the other hand, if there is UL data to be transmitted from the upper layer at a specific point in time, the UE transmits an SPS request message from the eNB again through, for example, MAC CE. The eNB sends an Ack message for the other of the three SPS configurations. The UE transmits UL data in a specific resource, for example, 100sec cycles according to the corresponding SPS configuration.

Transmission and reception of SA (Scheduling assignment)

The mode 1 terminal may transmit an SA (or a sidelink control signal, sidelink control information (SCI)) through a resource configured from a base station. The mode 2 terminal is configured with resources to be used for sidelink transmission from the base station. Then, the SA can be transmitted by selecting a time frequency resource from the configured resource.

The SA period may be defined as shown in FIG. 13. Referring to FIG. 13, a first SA period may start in a subframe separated by a predetermined offset (SAOffsetIndicator) indicated by higher layer signaling from a specific system frame. Each SA period may include an SA resource pool and a subframe pool for sidelink data transmission.

The SA resource pool may include the last subframe of the subframes in which SA is indicated to be transmitted in the subframe bitmap (saSubframeBitmap) from the first subframe of the SA period. As for the resource pool for sidelink data transmission, in the case of mode 1, a subframe used for actual data transmission may be determined by applying a time-resource pattern for transmission (T-RPT) or a time-resource pattern (TRP). As shown, when the number of subframes included in the SA period excluding the SA resource pool is greater than the number of T-RPT bits, T-RPT may be repeatedly applied, and the last applied T-RPT is the number of remaining subframes. It can be applied as truncated.

<Synchronization signal>

As described above, in the case of a V2X communication terminal, it is highly likely to be located outside the coverage of the base station. Even in this case, communication using the sidelink must be performed. For this, a problem in which a terminal located outside the coverage of a base station acquires synchronization is important.

Hereinafter, based on the above description, a method of synchronizing time and frequency in sidelink communication, particularly in communication between vehicles, vehicles and other terminals, and vehicles and infrastructure networks will be described.

D2D communication uses a Sidelink Synchronization Signal (SLSS), which is a synchronization signal transmitted from a base station, for time synchronization between terminals. In C-V2X, a satellite system (GNSS: Global Navigation Satellite System) can be additionally considered to improve synchronization performance. However, priority may be given to synchronization establishment or the base station may indicate information on priority. For example, in determining its transmission synchronization, the terminal preferentially selects a synchronization signal directly transmitted by the base station, and if it is located outside the coverage of the base station, it preferentially performs synchronization with the SLSS transmitted by the terminal inside the base station coverage. Fit.

On the other hand, a wireless terminal installed in a vehicle or a terminal mounted in a vehicle has relatively less battery consumption problems, and a satellite signal such as GPS can be used for navigation purposes, so time or frequency synchronization between terminals is set for the satellite signal. Can be used to Here, the satellite signal may correspond to a GNSS signal such as a GLObal NAvigation Satellite System (GLONAS), GALILEO, and BEIDOU in addition to the illustrated Global Positioning System (GPS).

Meanwhile, the sidelink synchronization signal may include a primary sidelink synchronization signal (PSSS) and a secondary sidelink synchronization signal (SSSS). The PSSS may be a Zadoff-chu sequence of a predetermined length or a structure similar to/modified/repeated to the PSS. In addition, unlike the DL PSS, other Zadoff Chu root indexes (eg, 26, 37) can be used. The SSSS may be an M-sequence or a structure similar/deformed/repeated to the SSS. If the terminals are synchronized from the base station, the SRN becomes the base station, and the SLSS becomes the PSS/SSS.

Unlike PSS/SSS of DL, PSSS/SSSS follows UL subcarrier mapping method. PSSCH (Physical Sidelink Synchronization Channel) is the basic system information that the UE needs to know first before transmitting and receiving sidelink signals (e.g., information related to SLSS, duplex mode (DM), TDD UL/DL configuration, and resources). It may be a channel through which pool related information, the type of application related to SLSS, subframe offset, broadcast information, etc.) are transmitted. The PSSCH may be transmitted on the same subframe as the SLSS or on a subsequent subframe. The DM-RS can be used for demodulation of the PSSCH.

The SRN may be a node that transmits SLSS and PSSCH. The SLSS may be in the form of a specific sequence, and the PSSCH may be in the form of a sequence representing specific information or a code word after pre-determined channel coding. Here, the SRN may be a base station or a specific sidelink terminal. In the case of partial network coverage or out of network coverage, the UE may be the SRN.

In addition, if necessary, the SLSS may be relayed for sidelink communication with an out of coverage terminal, and may be relayed through multiple hops. In the following description, relaying the synchronization signal is a concept including not only relaying the synchronization signal of the base station directly, but also transmitting a sidelink synchronization signal in a separate format in accordance with the synchronization signal reception time. In this way, since the sidelink synchronization signal is relayed, the in-coverage terminal and the out-of-coverage terminal can perform direct communication.

<NR sidelink>

As described above, unlike the LTE system-based V2X, there is a need for NR-based V2X technology in order to satisfy complex requirements such as autonomous driving.

In the case of NR V2X, it is intended to provide flexible V2X services in a wider variety of environments by applying the NR frame structure, newer rollers, and channel transmission/reception procedures. To this end, it is required to develop a resource sharing technology between a base station and a terminal, a sidelink carrier aggregation (CA) technology, a partial sensing technology for a pedestrian terminal, and a technology such as sTTI.

NR V2X decided to support unicast and groupcast as well as broadcast used in LTE V2X. At this time, it was decided to use the target group ID for groupcast and unicast, but it was decided to discuss whether to use the source ID later.

In addition, as it is decided to support HARQ for QOS, the control information also includes a HARQ process ID (HARQ Process ID). In LTE HARQ, PUCCH for HARQ is transmitted after 4 subframes after downlink transmission, but in NR HARQ, feedback timing is determined by, for example, a PUCCH resource indicator in DCI format 1_0 or 1_1 or HARQ feedback for PDSCH. PUCCH resources and feedback timing can be indicated by a timing indicator (PDSCH-to-HARQ feedback timing indicator).

Synchronization mechanism

NR V2X sidelink synchronization includes a sidelink synchronization signal(s) and PSBCH, and a sidelink source may include a UE along with GNSS and gNB.

Resource allocation

In NR V2X sidelink communication, at least two sidelink resource allocation modes, that is, mode 3 and mode 4 may be defined. In mode 3, the base station schedules sidelink resource(s) used by the terminal for sidelink transmission. In mode 4, the UE determines sidelink transmission resource(s) within sidelink resources configured by the base station or preconfigured sidelink resources.

Mode 4 can cover the following resource allocation sub-modes. That is, the UE automatically selects a sidelink resource for transmission, helps to select a sidelink resource for other UE(s), or consists of a grant configured for sidelink transmission, or a sidelink of another terminal(s) Transmission can be scheduled.

NR preemtion

In the case of a terminal critical to delay, such as a URLLC terminal, even data resources already allocated to other eMBB terminals may be preempted to use the data resources. In addition, information on which area of the data resource is preempted may be indicated to the terminal through the group common DCI.

Sidelink resource allocation/configuration based on Uu interface

NR Uu may allocate NR sidelink resources for a licensed carrier shared between Uu and the NR sidelink and/or a dedicated NR sidelink carrier. In this case, resource allocation may support dynamic resource allocation and activation/deactivation-based resource allocation. Activation/deactivation-based resource allocation may reuse SPS allocation or NR grant free type-2.

In the following description, SLSS id_net is a set of SLSS IDs used by terminals that select a synchronization signal of a base station as a synchronization reference among physical layer SLSS IDs {0, 1, and 335}, and may be {0, 1,, 167}. . In addition, the SLSS id_oon is a set of SLSS IDs used when the base station/terminals outside the coverage transmit synchronization signals by themselves, and may be {168, 169,, 335}.

The following descriptions are examples of satellite signals, mainly GNSS and GPS are used, but these may be replaced with other satellite signals. In addition, in the following description, V (vehicle)-UE may be a vehicle, and P (pedestrian)-UE may be a terminal moving by foot or a terminal moving by cycle. In addition, in the following description, the GPS timing sets a frame/subframe boundary based on an absolute time called the time acquired at the time of GPS reception (for example, UTC: Coordinated Universal Time or GPS time), and some or all of them May mean that is set as a subframe for sidelink signal transmission.

Example

In this embodiment, a group based beam reporting method is proposed.

In the conventional beam reporting, if only the beam having the largest RSRP is selected and used, the group-based reporting is a method of grouping and using several beams. Therefore, there is a need for a new method to group two or more beams for group-based reporting.

This embodiment proposes a method of grouping beams that are not spatially adjacent to each other when selecting and grouping M*N beams with a large RSRP on the assumption that N groups and M beams per group are used in group-based reporting. . By grouping the beams that are not spatially correlated, as a result, diversity can be secured and communication failure due to blockage can be reduced.

For example, in non-group-based beam reporting, the terminal selects and reports the beams having the largest N RSRP(s). In this case, N means the number of beams to be reported. This non-group based reporting may not achieve the basic purpose of beam selection. For example, spatially adjacent base station transmission beams having the largest N RSRP(s) may be selected.

14 shows the RSRP distribution of all base station transmission beams in the topographic map.

For beam reporting with the largest N RSRP(s), the UE selects and reports beams corresponding to the peak, for example, beams A and C when N=2. These reported beams are not suitable as backup beams, so the system may be less robust against blockage.

In this case, in order to obtain beams suitable for functioning as a backup, e.g. beams A and B, the base station sets more times for beam measurement and selection, resulting in large latency/overhead. can do.

To solve this problem, the terminal may be requested to report base station transmission beams having low spatial correlation. In this case, the selected and reported transmission beams may be suitable for improving the robustness of the system along with reduction of delay and overhead through multi-panel/beam diversity-transmission.

15 shows the results of different beam selections.

Referring to FIG. 15, it can be seen that reporting beams A and B having a low correlation compared to beams A and C having a high correlation indicates a high gain. Since beams A and C have a high correlation, beam A is blocked and beam C cannot be used as a good backup. Instead, beam B provides high robustness and can be used as a backup, preventing high RSRP reduction (>20dB).

As another example, for non-group-based reporting and group-based reporting, four or more reported beams and two or more reported beams may be supported.

For non-group substrate reporting, 4 reported beams cannot be simultaneously received by the terminal. The network needs to try multiple beam reporting and multiple CSI feedback in order to find beams suitable for spatial multiplexing. This is not efficient in terms of overhead and delay.

For group-based reporting, the two reported beams are not sufficient to support more base station/terminal panels. Therefore, there is sufficient motivation to improve group-based beam reporting for multi-beam operation. Group-based reporting may have the following two alternatives (Alt1 and Alt2).

In the alternative 1 aspect, the terminal reports one group with N=2 transmission beams.

In the alternative 2 aspect, the terminal reports N=2 groups with one transmission beam for each group.

A group-based report indicating which pairs of multiple beams can be received together at the base station may be regarded as one basic solution supporting multiple beam operation. Current group-based reporting, in which only N=2 transmission beams can be reported, limits system flexibility too much in multi-panel/TRP cases, and consequently the following points may be considered.

-To support more transmission beams and/or more groups in group-based reporting according to the requirements of multi-beam operation.

-Consider how to group transmission beams in consideration of spatial multiplexing in addition to being simultaneously received. In particular, the meaning of "receiving at the same time" may mean the following two cases.

• Multiple SSB/CSI-RSs corresponding to different TRP transmission beams may be received by multiple simultaneous spatial domain receive filters (e.g., different TXRUs).

Multiple SSB/CSI-RSs corresponding to different TRP transmission beams may be received by a single spatial domain receive filter (e.g., one same TXRU using the same receive analog beam).

The former means that signals carried by different panel/TRP beams are spatially multiplexed for multi-layer transmission.

In other words, in group based beam reporting, which is currently being discussed, a beam group is used for communication. One beam group is composed of a plurality of transmission beams. In this embodiment, a method of configuring the beams constituting the group is proposed.

In NR, RSRP for beams of each transmitter is reported to the base station in a random access process. Currently, RSRP is vulnerable to blockage by using only the largest beam or beam group, but using M beams that are spatially uncorrelated can maintain a relatively good state even in the presence of blockage. .

As described above, in the present embodiment, under the assumption that N groups and M beams per group are used in group-based reporting, when M*N beams having a large RSRP are selected and grouped, beams that are not spatially adjacent to each other are grouped together. Suggest a way to do it. By grouping the beams that are not spatially correlated, as a result, diversity can be secured and communication failure due to blockage can be reduced.

Therefore, this embodiment proposes a method of configuring non-adjacent beams into one group by obtaining values of the spatial identifiers, a horizontal beam ID and a vertical beam ID, based on the index of the beam. .

The horizontal beam ID is an identifier or index that divides beams transmitted from the base station in the horizontal direction of the antenna panel, and the vertical beam ID is an identifier or index that divides transmission beams in a vertical direction.

For convenience, the number of groups is referred to as N (N is a natural number greater than 0), and the number of beams in one group is referred to as M (M is a natural number greater than 0). The number of cases of N and M is as shown in Table 1, and the values are defined in advance by parameters.

[Table 1]

First proposal

When M>1, N=2, M*N beams with a large RSRP (8 in the case of M=2, N=2) are selected, and a group is formed through these beams.

Among them, we propose a method of finding a beam corresponding to the beam with the largest RSRP. The process of finding a specific beam and a beam corresponding thereto is simply called a beam group search process.

For example, the beam group search process uses a horizontal beam ID and a vertical beam ID, and then (the difference between the horizontal IDs of the two beams + the difference between the vertical beam IDs of the two beams) The beams with the largest value can be grouped.

The pair of beam groups created in this way is excluded from the beam group search process later. If (the difference between the horizontal beam identifiers of the two beams + the difference between the vertical beam identifiers of the two beams) is the same, grouping is performed randomly with the beams having the same value.

Ex1) M=4, N=2 (see Fig. 16)

The yellow circle represents the M*N beams with the largest RSRP, and the number in the middle of the circle represents the descending order of RSRP. In this case, a group can be configured as shown in FIG. 17 through the above beam group search process.

2nd proposal

In the case of M = 1 and N = 2, there is a very high possibility that a group consisting of adjacent beams is formed by applying the same method as in the first scheme. Therefore, in this case, as shown in FIG. 18, after selecting 8 beams in the order of RSRP, a beam group search process of one eye is applied.

Ex2) M=1, N=2

The third proposal

When M=1 and N=4, a beam group search process such as M=2 and N=2 is applied. Then, by merging the two groups created, one group with N=4 is created.

Ex3) M=1, N=4

After going through the process when M=2 and N=2 as shown in FIG. 19, two groups are merged to form one group as shown in FIG.

Proposal 4

When M=1 and N=8, the number of beams constituting one group is large and sufficient diversity is satisfied even if a beam group is formed without a separate beam group search process. Accordingly, as shown in FIG. 21, 8 beams having the largest RSRP are made into one group.

Hereinafter, a group-based beam reporting method of a terminal and a reception method of receiving a group-based beam report of a base station will be described in detail with reference to FIGS. 22 and 23.

22 is a flowchart of a group-based beam reporting method of a terminal according to another embodiment.

Referring to FIG. 22, the group-based beam reporting method 100 of the terminal includes M*N of a specific signal received from a base station or beams of a downlink physical channel having a large RSRP versus a reference signal (M and N are Selecting and grouping beams of a natural number greater than 0), but grouping spatially uncorrelated M beams into N groups (S110) and signal strength information versus reference signals for N groups (RSRP) Information) to the base station (S120).

The specific signal may be a synchronization signal or a reference signal, and the downlink physical channel may be a PBCH.

In this case, the reference signal strength versus signal strength information for the N groups may be an average value of the signal strengths versus the reference signals of the M beams constituting each group, or the signal strength versus the reference signal of one of the M beams constituting each group. have.

The step (S120) of reporting signal strength information versus reference signals for N groups to the base station may be performed in a random access process.

Meanwhile, the irrelevant beams may be spatially non-adjacent beams.

In the step of grouping the beams that are not spatially correlated into N groups (S110), a horizontal beam identifier that is an identifier that divides beams transmitted from the base station in the horizontal direction of the antenna panel as a spatial identifier based on the index of the beams. ID) and a vertical beam ID obtained by dividing the beams transmitted from the base station in the vertical direction of the antenna panel, and the beams that are not spatially correlated may be grouped into N groups.

In the step of grouping the spatially irrelevant beams into N groups (S110), the beams having the largest (difference between the horizontal identifiers of the two beams + the difference between the vertical beam identifiers of the two beams) are grouped into groups. I can.

The above-described beam group search process may be as described in the first to fourth plans described with reference to FIGS. 16 to 21, but is not limited thereto.

23 is a flowchart of a reception method in which a base station receives a group-based beam report according to another embodiment.

Referring to FIG. 23, in the reception method 200 for receiving a group-based beam report by a base station, the step of transmitting a specific signal or a downlink physical channel to a terminal (S210) and reference among beams of a specific signal or a downlink physical channel Selecting and grouping M*N beams having a large signal-to-signal strength (RSRP) (M and N are natural numbers greater than 0), but grouping M beams that are spatially uncorrelated into a group. And receiving (S220) signal strength information (RSRP information) versus a reference signal for the group from the terminal.

The information about the signal strength versus the reference signal for the N groups may be an average value of signal strengths versus the reference signals of the M beams constituting each group, or may be the signal strength versus the reference signal of one of the M beams constituting each group.

The step (S220) of receiving the reference signal versus signal strength information for the N groups from the terminal (S220) may be performed in a random access process.

The irrelevant beams may be spatially non-adjacent beams.

In the step (S220) of receiving signal strength information versus reference signals for N groups from the terminal, a horizontal beam identifier that is an identifier obtained by dividing beams transmitted from the base station in the horizontal direction of the antenna panel as a spatial identifier based on the index of the beams Beams that are not spatially correlated may be grouped into N groups by obtaining a value of a (Horizontal beam ID) and a vertical beam ID obtained by dividing the beams transmitted from the base station in the vertical direction of the antenna panel.

On the other hand, in the step (S220) of receiving signal strength information versus reference signals for N groups from the terminal, the beam having the largest (difference between the horizontal identifiers of the two beams + the difference between the vertical beam identifiers of the two beams) is selected. Can be grouped into groups.

The above-described beam group search process may be as described in the first to fourth plans described with reference to FIGS. 16 to 21, but is not limited thereto.

24 is a diagram showing a configuration of a base station 1000 according to another embodiment.

Referring to FIG. 24, a base station 1000 according to another embodiment includes a control unit 1010, a transmission unit 1020, and a reception unit 1030.

The control unit 1010 controls the overall operation of the base station 1000 according to group-based beam reporting using a spatially uncorrelated uncorrelated beam beam in 5G mobile communication required for carrying out the present invention.

The transmission unit 1020 and the reception unit 1030 are used to transmit and receive signals, messages, and data necessary for carrying out the above-described present invention with the terminal.

25 is a diagram showing a configuration of a user terminal 1100 according to another embodiment.

Referring to FIG. 25, a user terminal 1100 according to another embodiment includes a receiving unit 1110, a control unit 1120, and a transmitting unit 1130. The user terminal 1100 according to another embodiment may be a first terminal UE1 and a second terminal UE2 shown in FIG. 10 and the like.

The receiver 1110 receives downlink control information, data, and a message from the base station through a corresponding channel.

In addition, the controller 1120 controls the overall operation of the user terminal 1100 according to the group-based beam report using a spatially uncorrelated uncorrelated beam beam in 5G mobile communication required to perform the present invention. .

The transmitter 1130 transmits uplink control information, data, and a message to the base station through a corresponding channel.

The terminal 1100 performing group-based beam reporting includes M*N of a specific signal received from the base station 1000 or beams of a downlink physical channel having a greater signal strength (RSRP) compared to a reference signal (M and N are greater than 0). A control unit 1120 for selecting and grouping beams of a large natural number), but grouping spatially uncorrelated M beams into N groups, and signal strength information versus reference signals for N groups (RSRP information) It includes a transmission unit 1130 for reporting to the base station 1000.

The information about the signal strength versus the reference signal for the N groups may be an average value of signal strengths versus the reference signals of the M beams constituting each group, or may be the signal strength versus the reference signal of one of the M beams constituting each group.

The transmitter 1130 may be performed in a random access process.

The irrelevant beams may be spatially non-adjacent beams.

The control unit 1120 is a spatial identifier based on the index of the beams, a horizontal beam identifier (Horizontal beam ID), which is an identifier that divides the beams transmitted from the base station 1000 in the horizontal direction of the antenna panel, and a horizontal beam ID transmitted from the base station 1000. Beams that are not spatially correlated may be grouped into N groups by obtaining a value of a vertical beam ID by dividing the beams in the vertical direction of the antenna panel.

Meanwhile, the controller 1120 may group the beams having the largest (difference between the horizontal identifiers of the two beams + the difference between the vertical beam identifiers of the two beams) into groups.

The above-described beam group search process may be as described in the first to fourth plans described with reference to FIGS. 16 to 21, but is not limited thereto.

The group-based beam reporting method and apparatus using an uncorrelated beam in 5G mobile communication according to the present embodiments can secure diversity and reduce communication failures due to blockage.

The embodiments of the present invention described above can be implemented through various means. For example, embodiments of the present invention may be implemented by hardware, firmware, software, or a combination thereof.

In the case of implementation by hardware, the method according to embodiments of the present invention includes one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), and Programmable Logic Devices (PLDs). , Field Programmable Gate Arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, and the like.

In the case of implementation by firmware or software, the method according to the embodiments of the present invention may be implemented in the form of an apparatus, procedure, or function that performs the functions or operations described above. The software code may be stored in a memory unit and driven by a processor. The memory unit may be located inside or outside the processor, and may exchange data with the processor through various known means.

The above-described embodiments may be supported by standard documents disclosed in at least one of IEEE 802, 3GPP, and 3GPP2 wireless access systems. That is, steps, configurations, and parts not described in order to clearly reveal the present technical idea among the embodiments may be supported by the aforementioned standard documents. In addition, all terms disclosed in the present specification can be described by the standard documents disclosed above.

In addition, terms such as "system", "processor", "controller", "component", "module", "interface", "model", and "unit" described above are generally used in terms of computer-related entity hardware, hardware and software. It can mean a combination, software, or running software. For example, the above-described components may be, but are not limited to, a process driven by a processor, a processor, a controller, a control processor, an entity, an execution thread, a program, and/or a computer. For example, components can be both a controller or processor and an application running on a controller or processor. One or more components can reside within a process and/or thread of execution, and components can reside on one machine or be deployed on more than one machine.

The description above and the accompanying drawings are merely illustrative of the spirit of the present technology, and those of ordinary skill in the art can combine, separate, replace, and use configurations within a range not departing from the essential characteristics of the present technology. Various modifications and variations such as changes will be possible. Accordingly, the embodiments disclosed in the present specification are not intended to limit the present technical idea, but to describe it, and the scope of the present technical idea is not limited by these embodiments. The scope of protection of the present technical idea should be interpreted by the claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present specification.

Claims (18)

A group-based beam reporting method of a terminal,
Among the beams of a specific signal or downlink physical channel received from the base station, M*N beams having a large RSRP versus reference signal (M and N are natural numbers greater than 0) are selected and grouped, but the spatial correlation is Grouping the spatially uncorrelated M beams into N groups; And
Including the step of reporting the signal strength information relative to the reference signal for the N groups to the base station,
Grouping the spatially uncorrelated beams into N groups,
A spatial identifier for the beams applied to the beams transmitted from the base station, a horizontal beam ID, which is an identifier divided in the horizontal direction of the antenna panel, and a vertical beam ID, which is divided in the vertical direction of the antenna panel. Based on the value of the vertical beam ID, for the selected M*N beams, the RSRP corresponds to one beam in the largest order (the difference between the horizontal identifiers of the two beams + the vertical of the two beams) A method of reporting a beam based on a group of a terminal in which a beam having the largest beam identifier difference) value is calculated, and each of the calculated two beams corresponding to each other is grouped into N groups by M. The method of claim 1,
The reference signal-to-signal strength information for the N groups is an average value of the signal strengths versus the reference signals of the M beams constituting each group, or the signal strength versus the reference signal of one of the M beams constituting each group. Group-based beam reporting method. In claim 1,
The step of reporting signal strength information versus reference signals for the N groups to the base station is a group-based beam reporting method of a terminal performed in a random access process. The method of claim 1,
The non-correlated beams are beams that are not spatially adjacent to each other. delete delete As a reception method for the base station to receive a group-based beam report,
Transmitting a specific signal or a downlink physical channel to a terminal; And
Among the beams of the specific signal or downlink physical channel, M*N beams having a large RSRP compared to a reference signal (M and N are natural numbers greater than 0) are selected and grouped, but are spatially uncorrelated (spatially uncorrelated) comprising the step of receiving, from the terminal, reference signal versus signal strength information for N groups for grouping M beams into groups,
Receiving signal strength information versus reference signals for the N groups from the terminal,
A spatial identifier for the beams applied to the beams transmitted from the base station, a horizontal beam ID, which is an identifier divided in the horizontal direction of the antenna panel, and a vertical beam ID, which is divided in the vertical direction of the antenna panel. Based on the value of the vertical beam ID, for the selected M*N beams, the RSRP corresponds to one beam in the largest order (the difference between the horizontal identifiers of the two beams + the vertical of the two beams) Receives a group-based beam report from the base station receiving information on the reference signal versus signal strength for N groups in which the beam with the largest difference) value is calculated, and the calculated two beams corresponding to each other are grouped by M How to receive. The method of claim 7,
The reference signal-to-signal strength information for the N groups is an average value of the signal strengths versus the reference signals of the M beams constituting each group, or the base station, which is the signal strength versus the reference signal of one of the M beams constituting each group. A receiving method for receiving a group-based beam report. In clause 7,
The receiving of the reference signal strength versus reference signal strength information for the N groups from the terminal comprises: a receiving method of receiving a group-based beam report of a base station performed in a random access process. The method of claim 7,
A receiving method for receiving a group-based beam report of a base station, wherein the uncorrelated beams are beams that are not spatially adjacent. delete delete A terminal that performs group-based beam reporting,
Among the beams of a specific signal or downlink physical channel received from the base station, M*N beams having a large RSRP versus reference signal (M and N are natural numbers greater than 0) are selected and grouped, but the spatial correlation is A control unit for grouping the spatially uncorrelated M beams into N groups; And
Including a transmitter for reporting the signal strength information relative to the reference signal for the N groups to the base station,
The control unit,
A spatial identifier for the beams applied to the beams transmitted from the base station, a horizontal beam ID, which is an identifier divided in the horizontal direction of the antenna panel, and a vertical beam ID, which is divided in the vertical direction of the antenna panel. Based on the value of the vertical beam ID, for the selected M*N beams, the RSRP corresponds to one beam in the largest order (the difference between the horizontal identifiers of the two beams + the vertical of the two beams) A terminal that calculates a beam having the largest beam identifier difference) value, and groups each of the calculated two beams corresponding to each other into N groups by M. The method of claim 13,
The reference signal-to-signal strength information for the N groups is an average value of signal strengths versus reference signals of M beams constituting each group, or a signal strength versus reference signal of one of the M beams constituting each group. In claim 13,
The transmitter is a terminal that is performed in a random access process. The method of claim 13,
The non-correlated beams are beams that are not spatially adjacent. delete delete

Images