KR20200040193A - Methods for communicating using non-terrestrial network and apparatuses thereof - Google Patents

Abstract

The present disclosure relates to a technique in which a terminal and a network node perform communication using a non-ground network. In an aspect, according to embodiments of the present invention, provided are a method of a terminal for performing communication using a non-terrestrial network and an apparatus thereof, which comprises the steps of: receiving system information including reference round trip delay offset information of a non-terrestrial network cell; performing a random access procedure in the non-terrestrial network cell; receiving configuration information necessary to perform communication using the non-terrestrial network cell; and controlling discontinuous reception (DRX) operation based on the configuration information.

Description

Method and apparatus for performing communication using a non-terrestrial network {METHODS FOR COMMUNICATING USING NON-TERRESTRIAL NETWORK AND APPARATUSES THEREOF}

The present disclosure relates to a technique in which a terminal and a network node perform communication using a non-terrestrial network.

The amount of data transmission and reception using wireless communication technology is rapidly increasing as the spread of smart phones and the like increases and various uses of wireless communication devices are used. In addition, as the importance of low latency is highlighted, development of a new generation wireless communication technology (New RAT) after LTE technology is in progress.

In addition, terminals performing communication using wireless communication technologies are rapidly increasing, and communication demands in various environments and locations are increasing. In such a situation, there is a need to provide a communication service even in an environment in which a base station connected to a wired line can not be constructed to provide wider coverage.

To this end, research is being conducted on a non-terrestrial network that is wirelessly connected to the core network in the air rather than a base station built on the ground. Non-Terrestrial Network (Non-Terrestrial Network) refers to a network or segment of a network used to transmit airborne vehicles such as high altitude platforms (HAPS) or spaceborne vehicles such as satellites.

However, in the case of a non-terrestrial network, since the physical distance between the terminal and the core network is very far compared to the terrestrial network, it is necessary to change the protocol considering the delay time.

The present embodiments can provide a method and apparatus for performing communication between a terminal and a network node using a non-terrestrial network.

In one aspect, the present embodiments are a method for a terminal to perform communication using a non-terrestrial network, receiving system information including reference round trip delay offset information of a non-terrestrial network cell. And performing a random access procedure in the non-terrestrial network cell, and receiving configuration information necessary to perform communication using the non-terrestrial network cell, and controlling a discontinuous reception (DRX) operation based on the configuration information. It can provide a method comprising a.

In another aspect, the present embodiments provide system information including reference round trip delay offset information of a non-terrestrial network cell in a method in which a network node communicates with a terminal using a non-terrestrial network. It is possible to provide a method including a step of transmitting, performing a random access procedure with a terminal in a non-terrestrial network cell, and transmitting configuration information necessary for performing communication using a non-terrestrial network cell.

In yet another aspect, the present embodiments are non-terrestrial network cells and system information including reference round trip delay offset information of a non-terrestrial network cell in a terminal performing communication using a non-terrestrial network. A terminal device including a control unit for performing a random access procedure in a non-terrestrial network cell and receiving a configuration information necessary to perform communication by using a control unit for controlling the discontinuous reception (DRX) operation based on the configuration information Can provide.

In yet another aspect, the present embodiments are non-terrestrial network (Non-Terrestrial Network) in the network node for performing communication with the terminal, the system information and the ratio including the reference round trip delay offset information of the non-terrestrial network cell It is possible to provide a network node device including a transmitter for transmitting configuration information necessary for performing communication using a terrestrial network cell and a controller for performing a random access procedure with a terminal in a non-terrestrial network cell.

According to the present embodiments, a method and apparatus for performing communication between a terminal and a network node using a non-terrestrial network can be provided.

1 is a diagram briefly showing 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 the present embodiment can be applied.
3 is a diagram for describing a resource grid supported by a radio access technology to which the present embodiment can be applied.
4 is a diagram for describing a bandwidth part supported by a radio access technology to which the present embodiment can be applied.
5 exemplarily shows a synchronization signal block in a radio 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 view for explaining CORESET.
8 is a diagram illustrating an example in which different subcarrier spacings are arranged at a symbol level.
9 is a diagram for explaining a time domain structure in a next generation wireless communication system to which the present embodiment can be applied.
10 is a view for explaining various forms of a non-terrestrial network structure to which an embodiment can be applied.
11 exemplarily illustrates a DRX configuration information element according to an embodiment.
12 is a flowchart illustrating a terminal operation according to an embodiment.
13 is a diagram for describing a contention-based random access operation of a terminal according to an embodiment.
14 is a diagram for explaining a 2-step random access operation of a terminal according to an embodiment.
15 is a diagram illustrating a network node operation according to an embodiment.
16 is a diagram for explaining a timer control operation in a contention-based random access situation according to an embodiment.
17 is a diagram for explaining a timer control operation in a two-step random access situation according to an embodiment.
18 is a diagram for explaining a terminal configuration according to an embodiment.
19 is a diagram illustrating a network node configuration according to an embodiment.

Hereinafter, some embodiments of the present disclosure will be described in detail with reference to exemplary drawings. In adding reference numerals to the components of each drawing, the same components may have the same reference numerals as possible even though they are displayed on different drawings. In addition, in describing the present embodiments, when it is determined that a detailed description of a related known configuration or function may obscure the gist of the present technical concept, the detailed description may be omitted. When "include", "have", "consist of" and the like referred to herein are used, other parts may be added unless "~ only" is used. When a component is expressed in singular, it may include a case in which plural is included unless otherwise specified.

In addition, in describing the components of the present disclosure, terms such as first, second, A, B, (a), and (b) may be used. These terms are only for distinguishing the component from other components, and the essence, order, order, or number of the component is not limited by the term.

In the description of the positional relationship of the components, when two or more components are described as being "connected", "coupled" or "connected", the two or more components are directly "connected", "coupled" or "connected" It may be understood, but it may be understood that two or more components and other components may be further "interposed" to be "connected", "coupled" or "connected". Here, other components may be included in one or more of two or more components that are “connected”, “coupled”, or “connected” to each other.

In the description of temporal flow relations related to components, operation methods, production methods, etc., temporal sequential relationships such as "after", "after", "after", "before", etc. Or, when the flow sequential relationship is described, it may also include a case where the "direct" or "direct" is not continuous unless used.

On the other hand, when a numerical value for a component or its corresponding information (for example, level) is mentioned, even if there is no specific description, the numerical value or its corresponding information is various factors (eg, process factors, internal or external impact, Noise, etc.).

The wireless communication system in the present specification means a system for providing various communication services such as voice and data packets using radio resources, and may include a terminal, a base station, or 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 are code division multiple access (CDMA), frequency division multiple access (FDMA), timedivision multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), and single-electron frequency division multiple access (SC-FDMA). Alternatively, it can be applied to various various wireless access technologies such as non-orthogonal multiple access (NOMA). In addition, the wireless access technology may mean not only a specific access technology, but also a communication technology for each generation established by various communication consultation organizations such as 3GPP, 3GPP2, WiFi, Bluetooth, IEEE, and ITU. For example, CDMA may be implemented with a radio technology such as universal terrestrial radio access (UTRA) or CDMA2000. TDMA may be implemented with radio technologies such as global system for mobile communications (GSM) / general packet radio service (GPRS) / enhanced data rates for GSM evolution (EDGE). OFDMA can be implemented with wireless technologies such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, and Evolved UTRA (E-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 part of evolved UMTS (E-UMTS) using evolved-UMTS terrestrial radio access (E-UTRA), adopting OFDMA in the downlink and SC- in the uplink. Adopt FDMA. As described above, the present embodiments may be applied to a currently disclosed or commercialized wireless access technology, or may be applied to a wireless access technology currently being developed or to be developed in the future.

On the other hand, the terminal in the present specification is a comprehensive concept meaning a device including a wireless communication module that performs communication with a base station in a wireless communication system, WCDMA, LTE, NR, HSPA and IMT-2020 (5G or New Radio), etc. It should be interpreted as a concept including all of User Equipment (UE), Mobile Station (MS) in GSM, User Terminal (UT), Subscriber Station (SS), and wireless device. In addition, the terminal may be a user portable device such as a smart phone depending on the type of use, and in the V2X communication system, it may mean a vehicle, a device including a wireless communication module in the vehicle, or the like. Further, in the case of a machine type communication system, it may mean an MTC terminal equipped with a communication module, an M2M terminal, a URLLC terminal, etc. to perform machine type communication.

The base station or cell in the present specification refers to an end that communicates with a terminal in terms of a network, Node-B (Node-B), evolved Node-B (eNB), gNode-B (gNB), Low Power Node (LPN), Sector, site, various types of antennas, BTS (Base Transceiver System), access point, access point (e.g., transmission point, reception point, transmission / reception point), relay node (Relay Node) ), Mega cell, macro cell, micro cell, pico cell, femto cell, remote radio head (RRH), radio unit (RU), and small cell (small cell). In addition, the cell may mean to include a bandwidth part (BWP) in the frequency domain. For example, the serving cell may mean the Activation BWP of the terminal.

Since the various cells listed above have a base station that controls one or more cells, the base station can be interpreted in two ways. 1) a device that provides a mega cell, a macro cell, a micro cell, a pico cell, a femto cell, or a small cell in relation to the wireless area, or 2) the wireless area itself. In 1), all devices that provide a predetermined wireless area are controlled by the same entity or interact to configure the wireless area in a collaborative manner. Points, transmission / reception points, transmission points, reception points, and the like, according to a configuration method of a wireless area, are examples of base stations. In 2), the radio area itself, which receives or transmits a signal from the viewpoint of the user terminal or the neighboring base station, may be directed to the base station.

In this specification, a cell is a component carrier having a coverage of a signal transmitted from a transmission / reception point or a signal transmitted from a transmission / reception point, or a transmission / reception point itself. You can.

Uplink (Uplink, UL, or uplink) means a method of transmitting and receiving data to the base station by the terminal, downlink (Downlink, DL, or downlink) means a method of transmitting and receiving data to the terminal by the base station do. Downlink (downlink) may mean a communication or communication path from a multiple transmit and receive point to a terminal, and uplink (uplink) may mean a communication or communication path from a terminal to a multiple transmit and receive point. At this time, 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 multiple transmission / reception points.

In the uplink and downlink, control information is transmitted and received through control channels such as PDCCH (Physical Downlink Control CHannel), PUCCH (Physical Uplink Control CHannel), and PDSCH (Physical Downlink Shared CHannel), PUSCH (Physical Uplink Shared CHannel), etc. The same data channel is configured to transmit and receive data. Hereinafter, a situation in which signals are transmitted and received through channels such as PUCCH, PUSCH, PDCCH, and PDSCH is also referred to as 'transmitting and receiving PUCCH, PUSCH, PDCCH and PDSCH'. do.

In order to clarify the description, hereinafter, the technical idea is mainly focused on the 3GPP LTE / LTE-A / NR (New RAT) communication system, but the technical features are not limited to the communication system.

3GPP develops 5G (5th-Generation) communication technology to meet the requirements of ITU-R's next-generation radio access technology after research on 4G (4th-Generation) communication technology. Specifically, 3GPP develops a new NR communication technology separate from LTE-A pro and 4G communication technology, which have improved LTE-Advanced technology to meet the requirements of ITU-R as a 5G communication technology. LTE-A pro and NR both refer to 5G communication technology. Hereinafter, 5G communication technology will be described with reference to NR when a specific communication technology is not specified.

The operating scenario in NR has defined various operating scenarios by adding considerations for satellite, automobile, and new verticals in the existing 4G LTE scenario, and has an eMBB (Enhanced Mobile Broadband) scenario and high terminal density in terms of service It is deployed in the range and supports the Massive Machine Communication (mmmTC) scenario, which requires low data rate and asynchronous connection, and the Ultra Reliability and Low Latency (URLLC) scenario, which requires high responsiveness and reliability and supports high-speed mobility. .

To satisfy this scenario, NR discloses a wireless communication system to which a new waveform and frame structure technology, low latency technology, ultra-high-bandwidth (mmWave) support technology, and forward compatibility technology are applied. In particular, in the NR system, various technical changes are proposed in terms of flexibility in order to provide forward compatibility. The main technical features of NR are described below with reference to the drawings.

<NR system general>

1 is a diagram briefly showing the structure of an NR system to which the present embodiment can be applied.

Referring to FIG. 1, the NR system is divided into 5GC (5G Core Network) and NR-RAN parts, and NG-RAN is controlled for a user plane (SDAP / PDCP / RLC / MAC / PHY) and UE (User Equipment). It consists of gNB and ng-eNBs that provide a plane (RRC) protocol termination. The gNB interconnects or the gNB and ng-eNB are interconnected via an Xn interface. gNB and ng-eNB are each connected to 5GC through an NG interface. The 5GC may be configured to 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 in user data. The NR includes support for frequency bands below 6 GHz (FR1, Frequency Range 1) and frequency bands above 6 GHz (FR2, Frequency Range 2).

gNB means a base station providing NR user plane and control plane protocol termination to the terminal, and ng-eNB means a base station providing E-UTRA user plane and control plane protocol termination to the terminal. The base station described in this specification should be understood as a meaning encompassing gNB and ng-eNB, and may be used in a sense to refer to gNB or ng-eNB separately if necessary.

<NR wave form, pneumatics 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 multiple input multiple output (MIMO), and has the advantage of being able to use a receiver of high complexity with high frequency efficiency.

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

Specifically, the NR transmission numerology is determined based on sub-carrier spacing (CP) and cyclic prefix (CP). As shown in Table 1 below, μ value is used as an exponential value of 2 based on 15 kHz to exponentially Is changed to

μ Subcarrier spacing 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 numerology can be divided into 5 types according to the subcarrier spacing. This is different from that in which the subcarrier spacing of LTE, which is one of 4G communication technologies, is fixed at 15 kHz. Specifically, subcarrier intervals used for data transmission in NR are 15, 30, 60, and 120 kHz, and subcarrier intervals used for synchronization signal transmission are 15, 30, 120, and 240 kHz. In addition, the extended CP is applied only to the 60 kHz subcarrier interval. On the other hand, a frame structure in NR is defined as a frame having a length of 10 ms, which is composed 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 a 15 kHz subcarrier interval, one subframe is composed of one slot, and each slot is composed of 14 OFDM symbols.

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

Referring to FIG. 2, a slot is fixedly composed of 14 OFDM symbols in the case of a normal CP, but the length in the time domain of the slot may vary according to the subcarrier interval. For example, in the case of a numerology having a 15 kHz subcarrier spacing, the slot is 1 ms long and is configured to have the same length as the subframe. On the contrary, in the case of a neurology having a 30 kHz subcarrier spacing, a slot is composed of 14 OFDM symbols, but may be included in two slots in one subframe with a length of 0.5 ms. That is, the subframe and the frame are defined with a fixed time length, and the slot is defined by the number of symbols, so that the time length may vary according to the subcarrier interval.

Meanwhile, the NR defines a basic unit of scheduling as a slot, and also introduces a mini-slot (or sub-slot or non-slot based schedule) to reduce transmission delay in a radio section. If a wide subcarrier interval is used, the transmission delay in a radio section can be reduced because the length of one slot is inversely shortened. The mini-slot (or sub-slot) is for efficient support for URLLC scenarios and can be scheduled in units of 2, 4, and 7 symbols.

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

NR is designed to support a total of 256 slot formats, of which 62 slot formats are used in 3GPP 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 downlink symbols and uplink symbols are combined are supported. In addition, the NR supports that data transmission is scheduled in one or more slots. Accordingly, the base station may inform the UE whether the slot is a downlink slot, an uplink slot, or a flexible slot using a slot format indicator (SFI). The base station may indicate a slot format by indicating an index of a table configured through UE-specific RRC signaling using SFI, and dynamically indicate through DCI (Downlink Control Information) or static or through RRC It can also be given quasi-statically.

<NR Physical Resources>

With regard to physical resources in the NR, antenna ports, resource grids, resource elements, resource blocks, bandwidth parts, etc. are considered. do.

The antenna port is defined such that a channel carrying a symbol on the antenna port can be inferred from a channel carrying another symbol on the same antenna port. If the large-scale property of a channel carrying a symbol on one antenna port can be deduced from a channel carrying a symbol on another antenna port, the two antenna ports are QC / QCL (quasi co-located or quasi co-location). Here, a wide range of characteristics includes one or more of Delay spread, Doppler spread, Frequency shift, Average received power and Received Timing.

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

Referring to FIG. 3, a resource grid may exist according to each neuromerging because the NR supports a plurality of neuromerging on the same carrier. In addition, the resource grid may exist according to the antenna port, subcarrier spacing, and transmission direction.

A resource block consists of 12 subcarriers and is defined only on the frequency domain. Further, a resource element is composed 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, in NR, "Point A" serving as a common reference point for a resource block grid, a common resource block, and a virtual resource block are defined.

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

Unlike LTE, where the carrier bandwidth is fixed at 20Mhz in NR, the maximum carrier bandwidth for each subcarrier interval is set from 50Mhz to 400Mhz. Therefore, it is not assumed that all terminals use all of these carrier bandwidths. Accordingly, in the NR, as illustrated in FIG. 4, a terminal may be used by designating a bandwidth part (BWP) within a 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 with time. A maximum of 4 bandwidth parts are configured in the uplink and downlink, respectively, and data is transmitted and received using the bandwidth part activated at a given time.

In the case of a paired spectrum, the uplink and downlink bandwidth parts are independently set, and in the case of an unpaired spectrum, unnecessary frequency re-tunning is prevented between downlink and uplink operation. For this, the bandwidth part of the downlink and the uplink is set in pairs so that the center frequency can be shared.

<NR initial connection>

In NR, a terminal accesses a 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, acquires a physical layer cell ID, and acquires system information using a synchronization signal block (SSB) transmitted by the base station.

5 exemplarily shows a synchronization signal block in a radio 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 a secondary synchronization signal (SSS) occupying 1 symbol and 127 subcarriers, and 3 OFDM symbols and a PBCH spanning 240 subcarriers, respectively.

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

SSB can be transmitted up to 64 times in 5 ms. Multiple SSBs are transmitted with different transmission beams within 5 ms time, and the terminal performs detection by assuming that SSBs are transmitted every 20 ms period when viewed based on a specific one 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 below 3 GHz, and up to 8 SSBs can be transmitted using up to 8 different beams in the frequency band from 3 to 6 GHz and up to 64 in the frequency band above 6 GHz.

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

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

The UE may acquire MIB through the PBCH of the SSB. The MIB (Master Information Block) includes minimum information for the UE to receive the remaining system information (RMSI, Remaining Minimum System Information) broadcast by the network. In addition, PBCH is information on the location of the first DM-RS symbol on the time domain, information for the UE to monitor SIB1 (for example, SIB1 neuromerging 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 pneumatic information is equally applied to some messages used in the random access procedure for accessing the base station after the terminal completes the cell search procedure. For example, pneumatic information of SIB1 may be applied to at least one of messages 1 to 4 for a random access procedure.

The aforementioned RMSI may mean System Information Block 1 (SIB1), and SIB1 is broadcast periodically (ex, 160 ms) in a cell. SIB1 includes information necessary for the UE to perform the initial random access procedure, and is periodically transmitted through the PDSCH. In order to receive SIB1, the UE must receive pneumatic information used for SIB1 transmission and control resource set (CORESET) information used for scheduling of SIB1 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 a terminal's request.

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 PRACH. Specifically, the random access preamble is transmitted to the base station through PRACH composed of continuous radio resources in a specific slot that is periodically repeated. Generally, a contention-based random access procedure is performed when the UE initially accesses a cell, and a non-competition-based random access procedure is performed when random access is performed for beam failure recovery (BFR).

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, a 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 the random access preamble received by the base station. The 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 terminal applies TAC and stores a temporary C-RNTI. In addition, 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 capable of identifying the terminal should be included.

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

<NR CORESET>

The downlink control channel in the NR is transmitted in a control resource set (CORESET) having a length of 1 to 3 symbols, and transmits uplink / downlink scheduling information, slot format index (SFI), and transmit power control (TPC) information. .

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

7 is a view 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 a time domain. In addition, CORESET is defined as a multiple of 6 resource blocks from the frequency domain to the carrier bandwidth.

The first CORESET is indicated through the MIB as part of the initial bandwidth part configuration to receive additional configuration information and system information from the network. After establishing a connection with the base station, the UE may configure by receiving one or more CORESET information through RRC signaling.

In this specification, frequency, frame, subframe, resource, resource block, region, band, subband, control channel, data channel, synchronization signal, various reference signals, various signals or various messages related to NR (New Radio) Can be interpreted as meaning used in the past or present or various meanings used in the future.

NR (New Radio)

NR, the next-generation wireless communication technology under standardization in 3GPP, is a wireless access technology that provides an improved data rate compared to LTE and can satisfy various QoS requirements required for each segmented and specific usage scenario. . In particular, as a representative use scenario of NR, enhancement mobile BroadBand (eMBB), massive MTC (mMTC) and ultra reliable and low latency communications (URLLC) have been defined. As a method for satisfying the requirements for each scenario, a flexible frame structure compared to LTE is provided. The NR frame structure supports a multiple subcarrier based frame structure. The default subcarrier spacing (SCS) is 15 kHz, and 15 kHz * 2 ^ n to support 5 types of SCS.

8 is a diagram illustrating an example in which different subcarrier spacings are arranged at a symbol level.

Referring to FIG. 8, it can be seen that the length of the time axis of the slot varies according to numerology. That is, it can be seen that the shorter the slot length, the larger the SCS. In addition, the number of OFDM symbols constituting the slot in the NR and the y value are fixed to have a value of y = 14 regardless of the SCS value in the case of a normal CP. Accordingly, an arbitrary slot is composed of 14 symbols. In addition, all symbols may be used for DL transmission, or all symbols may be used for UL transmission, or may be used in the form of DL portion + (gap) + UL portion depending on the transmission direction of the corresponding slot. have.

In addition, in any numerology (or SCS), a mini-slot is defined consisting of fewer symbols than the aforementioned slots. A short-length time-domain scheduling interval for transmitting / receiving mini-slot-based uplink / downlink data may be set, or a long length time-domain scheduling interval for transmitting / receiving uplink / downlink data through slot aggregation may be configured. have. In particular, when transmitting / receiving latency-sensitive data such as URLLC, it is difficult to satisfy latency requirements when scheduling 1 ms (14 symbols) based slots defined in a numerology-based frame structure with a small SCS value such as 15 kHz. You can. Therefore, a mini-slot defined with a smaller number of OFDM symbols than a slot composed of 14 symbols can be defined and scheduling based on this can satisfy the requirements of URLLC.

9 is a diagram for explaining a time domain structure in a next generation wireless communication system to which the present embodiment can be applied.

Referring to FIG. 9, NR supports the following structures in the time axis. The difference from the existing LTE is that the basic scheduling unit has been changed to the aforementioned slot in NR. Also, regardless of the subcarrier spacing, the slot is composed of 14 OFDM symbols as shown in FIG. 9. On the other hand, it supports a non-slot structure (mini-slot structure) composed of 2,4,7 OFDM symbols, which are smaller scheduling units. The non-slot structure can be used as a scheduling unit for URLLC services.

■ Radio frame: Fixed 10ms regardless of numerology regardless of pneumatics (SCS).

■ Subframe: Fixed 1ms as a reference for time duration on the time domain. Unlike LTE, it is not used as a scheduling unit for data and control signals.

■ Slot: Mainly used for eMBB scenario (Mainly for eMBB). Include 14 OFDM symbols (Include 14 OFDM symbols).

■ Non-slot (i.e. mini-slot): Mainly used for URLLC scenarios, but is not limited to (Mainly for URLLC, but not limited to URLLC only). Includes 2, 4 or 7 OFDM symbols (Include 2, 4, or 7 OFDM symbols).

■ One TTI duration: A Time duration for data / control channel transmission. A number of OFDM symbols per a slot / non-slot in the time main

Non-Terrestrial Network

Non-Terrestrial Network (Non-Terrestrial Network) refers to a network or segment of a network using airborne vehicles such as High Altitude Platform (HAPS) or spaceborne vehicles such as satellites.

Spaceborne vehicles: May include Low Earth Orbiting (LEO) satellites, Medium Earth Orbiting (MEO) satellites, Geostationary Earth Orbiting (GEO) satellites as well as Highly Elliptical Orbiting (HEO) satellites.)

● Airborne vehicles: High Altitude Platforms (HAPs) encompassing Unmanned Aircraft Systems (UAS) including Lighter than Air UAS (LTA), Heavier than Air UAS (HTA), all operating in altitudes typically between 8 and 50 km, quasi-stationary

3GPP is developing a technology supporting NR operation in a non-terrestrial network using the above-described satellite or air transport vehicle. However, the distance between a base station and a terminal in a non-terrestrial network is longer than a terrestrial network using a terrestrial base station. Accordingly, a very large round trip delay (RTD) may occur. For example, it is known that the RTD is 544.751 ms in the NTN scenario using GEO located at an altitude of 35,768 km, and the RTD is 3.053 ms in the NTN scenario using HAPS located at an altitude of 229 km. In addition, RTDs in NTN scenarios using LEO satellite systems can appear up to 25.76 ms. As described above, in order to perform a communication operation to which the NR protocol is applied in a non-terrestrial network, a technique for supporting a base station and a terminal to perform an NR operation even under such propagation delay is required.

10 is a view for explaining various forms of a non-terrestrial network structure to which an embodiment can be applied.

Referring to FIG. 10, a non-terrestrial network may be designed with a structure in which a terminal performs wireless communication using a device located above. For example, a non-terrestrial network may be implemented with a structure in which a satellite or air transport device is positioned between a terminal and a base station (gNB) to relay communication, such as a 1010 structure. As another example, the non-terrestrial network may be implemented with a structure in which a satellite or an air transport device performs communication with a terminal by performing part or all of a base station (gNB) function, such as a 1020 structure. As another example, a non-terrestrial network may be implemented with a structure in which a satellite or air transport device is positioned between a relay node and a base station (gNB) to relay communication, such as a 1030 structure. As another example, the non-terrestrial network may be implemented with a structure in which a satellite or air transport device performs a communication with a relay node by performing part or all of a base station (gNB) function, such as a 1040 structure.

Accordingly, in this specification, a configuration for performing communication with a terminal in connection with a core network is described as a network node or a base station, but this may mean the aforementioned airborne vehicles or spaceborne vehicles. If necessary, a network node or a base station may mean the same device as 1020 and 1040, or may be used to distinguish different devices such as 1010 and 1030 according to a non-terrestrial network structure.

That is, in the following, a network node or a base station refers to a device that transmits and receives data to and from a terminal in a non-terrestrial network structure, and controls the access procedure and data transmission and reception procedure of the terminal. Accordingly, when the airborne vehicles or spaceborne vehicle devices perform some or all of the functions of the base station, the network node or the base station may mean airborne vehicles or spaceborne vehicle devices. Alternatively, when an airborne vehicle or spaceborne vehicle plays a role of relaying a signal of a separate ground base station, the network node or base station may mean a ground base station.

MAC procedure

The MAC protocol that provides services such as mapping between logical channels and transport channels, multiplexing / demultiplexing of MAC SDUs, scheduling information reporting, and priority processing controls media access through various MAC procedures. 3GPP TS 38.321, the NR MAC protocol standard, discloses techniques for various MAC procedures, such as random access procedures, uplink timing alignment maintenance, DL-SCH / UL-SCH data transmission, and discontinuous reception (DRX). However, the NR MAC procedure has been standardized assuming operation in a short delay environment in a terrestrial network. Therefore, in the long propagation delay of the non-terrestrial network, there may be a problem in performing the existing MAC procedure.

For example, a DRX procedure operation for reducing power consumption of a terminal may cause a problem in a long propagation delay.

11 exemplarily illustrates a DRX configuration information element according to an embodiment. Referring to FIG. 11, definitions for each parameter configured by RRC are as follows.

-drx-HARQ-RTT-TimerDL (per DL HARQ process): the minimum duration before a DL assignment for HARQ retransmission is expected by the MAC entity .

-drx-HARQ-RTT-TimerUL (per UL HARQ process): the minimum duration before a UL HARQ retransmission grant is expected by the MAC entity .

-drx-RetransmissionTimerDL (per DL HARQ process): the maximum duration until a DL retransmission is received (the maximum duration until a DL retransmission is received).

-drx-RetransmissionTimerUL (per UL HARQ process): the maximum duration until approval for UL retransmission is received (the maximum duration until a grant for UL retransmission is received).

The base station may configure the aforementioned DRX parameter used to control PDCCH monitoring in the MAC entity of the terminal to the terminal through RRC signaling. When in RRC CONNECTED, if DRX is configured, the MAC entity of the terminal can discontinuously monitor the PDCCH using the DRX operation. If not, the MAC entity should continuously monitor the PDCCH.

Meanwhile, in the conventional NR technique, the HARQ retransmission operation is performed by instructing the scheduling through the PDCCH when the NACK is transmitted according to the HARQ reception failure. Therefore, time is required according to the round trip delay in order to process HARQ feedback and scheduling.

11, drx-HARQ-RTT-Timer may be configured by selecting a value between 0 and 56 symbols. The 56 symbols correspond to 4 ms for 15 kHz subcarrier spacing. Therefore, the drx-HARQ-RTT-Timer of the conventional NR DRX procedure cannot support the large round trip delay of the non-ground network. In addition, drx-RetransmissionTimer can be configured by selecting a value from 0 to 320 slots. 320 slots corresponds to 320 ms in the case of 15 kHz subcarrier spacing. However, when the subcarrier spacing is increased, the duration is shortened. Therefore, the drx-RetransmissionTimer of the conventional NR DRX procedure cannot support a large round trip delay of a non-terrestrial network.

As such, the conventional NR MAC procedure has been standardized assuming operation in a short delay environment in a terrestrial network. Accordingly, there is a problem that the NR MAC procedure cannot be performed in a propagation delay environment of a non-ground network. For example, the drx-HARQ-RTT-Timer or drx-RetransmissionTimer parameter does not support the value required for a round trip in a propagation delay environment of a non-terrestrial network, so the terminal has a problem that it cannot perform a DRX procedure.

The present disclosure, devised to solve these problems, is intended to provide a technique capable of effectively performing an NR MAC procedure in a propagation delay environment of a non-terrestrial network. Also, it is intended to provide a technique for performing an individual procedure required in a communication process such as a random access procedure between a terminal and a network node, a scheduling request procedure, a HARQ procedure, and a DRX operation in consideration of a long delay in a non-terrestrial network.

Each embodiment provided below may be applied to an NR terminal through an NR base station, or may be applied to an LTE terminal through an LTE base station. In addition, each embodiment provided below may be applied to an LTE terminal connected to an eLTE base station connected through a 5G system (or 5G Core Network), and EN-DC (E-UTRAN NR) that simultaneously provides LTE and NR wireless connectivity. Dual Connectivity) terminal or NE-DC terminal.

12 is a flowchart illustrating a terminal operation according to an embodiment.

Referring to FIG. 12, a terminal performing communication using a non-terrestrial network performs a step of receiving system information including reference round trip delay offset information of a non-terrestrial network cell (S1210). You can. For example, the reference round trip delay offset information may be determined based on a signal transmission time between a terminal and a network node. For example, the reference round trip delay offset information may be determined based on a time difference in which a signal transmitted by a terminal or a network node is received at a network node or terminal. As another example, the reference round trip delay offset information may be determined based on a time difference when a response signal to a signal transmitted by the terminal is received by the terminal.

The reference round trip delay offset information may be included in system information transmitted by a network node and received by the terminal. The reference round trip delay offset information may be included in the system information, either explicitly or implicitly.

The UE may perform a step of performing a random access procedure in a non-terrestrial network cell (S1220). For example, after receiving the system information, the terminal may perform a random access procedure to access a network node using a non-terrestrial network.

For example, in the case of a contention-based random access procedure, the UE starts a timer for resolving contention when a time according to the reference round trip delay offset information elapses after transmitting the message 3 (MSG3) and transmitting the message 3 and When the contention resolution is completed, the step of stopping the timer may be performed. That is, when the time equal to the reference round trip delay offset has elapsed after the transmission of the message 3, the terminal monitors the reception of the message 4. In order to determine whether contention is resolved, the terminal starts a timer for resolving the contention when the time of the reference round trip delay offset has elapsed after the message is transmitted, and when the message 4 is normally received, the timer is stopped to complete the random access procedure. .

As another example, in the case of a two-step random access procedure, the UE transmits the message A (MSG A), and after the message A is transmitted, when a time according to the reference round trip delay offset information elapses, starting the response timer and the message A When the message B, which is a response message for, is received, the step of stopping the response timer may be performed. That is, when performing a two-step random access procedure consisting of message A transmission and message B reception, the terminal transmits message A and starts a response timer to determine whether to receive message B when the time equal to the reference round trip delay offset has elapsed. Monitor. Then, when the message B is normally received, the terminal ends the response timer and completes the random access procedure.

The above-described random access procedure will be described in more detail with reference to the drawings below.

Meanwhile, the terminal may perform a step of receiving configuration information necessary to perform communication using a non-ground network cell (S1230). For example, the configuration information may include a discontinuous reception HARQ drx HARQ Round Trip Time (RTT) timer or a scheduling request (SR) prohibition timer. Here, the discontinuous received HARQ RTT (drx HARQ Round Trip Time) timer or SR (Scheduling Request) prohibit timer may be set to a value greater than the reference round trip delay offset.

The terminal may perform a step of controlling the discontinuous reception (DRX) operation based on the configuration information (S1240). For example, the terminal may perform a DRX operation using a timer included in the configuration information.

As an example, the terminal performs a DRX operation based on a HARQ RTT (drx HARQ Round Trip Time) timer. In addition, if a disable indication for the HARQ feedback operation is received, the terminal may disable (disable) the discontinuous reception HARQ drx HARQ Round Trip Time (RTT) timer. That is, when the network node instructs the deactivation for the HARQ feedback operation, the terminal disables (disables) the discontinuous received HARQ drx HARQ Round Trip Time (RTT) timer and does not perform the HARQ feedback operation.

As another example, the terminal may perform a scheduling request operation based on an SR (Scheduling Request) prohibit timer.

As described above, the terminal may process the reference round trip delay offset information received from the base station by reflecting the increase in the delay time according to the non-terrestrial network using the MAC procedure.

Hereinafter, the terminal operation in the random access procedure briefly described above will be described in more detail with reference to the drawings.

13 is a diagram for describing a contention-based random access operation of a terminal according to an embodiment.

13, the terminal transmits a random access preamble to access a non-terrestrial network cell (S1310). For example, the UE may select and transmit one of a predetermined number of preambles using PRACH.

The terminal receives a random access response message including response information for the random access preamble (S1320). For example, the terminal monitors whether a random access response message is received in a random access response window set based on random access preamble transmission resource information. If the random access response message identified by the temporary identifier associated with the random access preamble transmission is received in the random access response window, the terminal receives the random access response message.

Thereafter, the UE transmits MSG 3 including request information for requesting an RRC connection (S1330). For example, MSG 3 may include information requesting radio resource allocation required for uplink transmission.

When the MSG 3 is transmitted, the terminal performing the access to the above-mentioned non-terrestrial network cell starts a timer for resolving contention after a predetermined period of time (S1340). For example, a predetermined period may be determined based on reference round trip delay offset information received through system information. That is, when MSG 3 is transmitted, the UE starts a timer for resolving contention after a certain period of time determined according to the reference round trip delay offset has elapsed. Here, the timer for resolving the competition may be configured in advance in the terminal or may be received through a separate message.

While the timer for contention resolution is in operation, the terminal receives MSG 4 including information for contention resolution (S1350). When the MSG 4 is received and the terminal is connected to the non-terrestrial network cell, the terminal stops a timer for resolving contention (S1360).

Through this, the terminal operates the competition cancellation timer in consideration of the long round trip delay generated in the non-terrestrial network environment, thereby preventing occurrence of random access procedure failure due to the expiration of the competition cancellation timer even when MSG 4 is transmitted. .

14 is a diagram for explaining a 2-step random access operation of a terminal according to an embodiment.

Referring to FIG. 14, even in a 2-step random access process, the terminal may determine a timer start time using reference round trip delay offset information to prevent detection of random access failure due to expiration of the response timer.

The two-step random access procedure is to simplify the general four-step random access procedure of random access preamble transmission, random access response reception, MSG 3 transmission, and MSG 4 reception described in FIG. 13 to two steps to support a fast random access procedure. Technology.

For example, the UE simultaneously transmits the MSG A including the random access preamble and MSG 3 (S1410). The random access preamble is transmitted on the PRACH, and the MSG 3 is transmitted on the PUSCH.

After the MSG A is transmitted, the UE starts a response timer after a predetermined delay time determined based on the reference round trip delay offset information (S1430). For example, the terminal starts a response timer after the time included in the reference round trip delay offset information has elapsed.

The terminal monitors whether or not the MSG B is received while the response timer is running, and receives the MSG B (S1430). For example, MSG B includes some or all of the information of MSG 4 and the random access response message in FIG. 13.

When the MSG B is received, the terminal stops the response timer and ends the random access procedure (S1440).

As described above, even in the random access procedure, the occurrence of an unexpected random access failure situation can be prevented by considering a long round trip delay according to the non-terrestrial network configuration.

Hereinafter, the operation of the base station corresponding to the operation of the above-described terminal will be described. The portion associated with the operation of the terminal in the operation of the base station is described above, and may be omitted to avoid unnecessary duplication.

15 is a diagram illustrating a network node operation according to an embodiment.

Referring to FIG. 15, a network node performing communication with a terminal using a non-terrestrial network performs a step of transmitting system information including reference round trip delay offset information of a non-terrestrial network cell. It can be done (S1510). For example, the reference round trip delay offset information may be determined based on a signal transmission time between a terminal and a network node. For example, the reference round trip delay offset information may be determined based on a time difference in which a signal transmitted by a terminal or a network node is received at a network node or terminal. As another example, the reference round trip delay offset information may be determined based on a time difference when a response signal to a signal transmitted by the terminal is received by the terminal. Also, the reference round trip delay offset information may be included in the system information in an explicit or implicit form.

The network node may perform a step of performing a random access procedure with the terminal in the non-ground network cell (S1520). For example, a network node may perform a random access procedure with a terminal attempting to access a network node using a non-terrestrial network.

For example, in the case of a contention-based random access procedure, the network node receives message 3 (MSG3) from the terminal. After the message 3 is transmitted, when the time according to the reference round trip delay offset information elapses, the terminal starts a timer for resolving contention. The network node transmits a message 4 including the response information to the message 3 to the terminal. When the message 4 is received, the terminal stops the timer for contention cancellation and ends the random access procedure. That is, when the time equal to the reference round trip delay offset has elapsed after the transmission of the message 3, the terminal monitors the reception of the message 4.

As another example, in the case of the 2-step random access procedure, the network node receives message A (MSG A). After the message A is transmitted, when the time according to the reference round trip delay offset information elapses, the terminal starts a response timer. The network node sends a message B, which is a response message to message A, to the terminal. When the terminal receives the message B, the response timer is stopped. That is, when performing a two-step random access procedure consisting of message A transmission and message B reception, the terminal transmits message A and starts a response timer to determine whether to receive message B when the time equal to the reference round trip delay offset has elapsed. Monitor. Then, when the message B is normally received, the terminal ends the response timer and completes the random access procedure.

The network node may perform a step of transmitting configuration information necessary for performing communication using a non-ground network cell (S1530). For example, the configuration information may include a discontinuous reception HARQ drx HARQ Round Trip Time (RTT) timer or a scheduling request (SR) prohibition timer. Here, the discontinuous received HARQ RTT (drx HARQ Round Trip Time) timer or SR (Scheduling Request) prohibit timer may be set to a value greater than the reference round trip delay offset.

In addition, the network node may transmit the indication information for disabling (Disable) the HARQ feedback operation of the terminal to the terminal. When the indication information is received, the terminal may disable (disable) the discontinuous reception HARQ RTT (drx HARQ Round Trip Time) timer. As an example, the terminal performs a DRX operation based on a HARQ RTT (drx HARQ Round Trip Time) timer. That is, when the network node instructs the deactivation for the HARQ feedback operation, the terminal disables (disables) the discontinuous reception HARQ drx HARQ Round Trip Time (RTT) timer and does not perform the HARQ feedback operation. As another example, the terminal may perform a scheduling request operation based on an SR (Scheduling Request) prohibit timer.

As described above, the terminal may process the reference round trip delay offset information received from the base station by reflecting the increase in the delay time according to the non-terrestrial network using the MAC procedure.

Hereinafter, a detailed embodiment for performing an operation in consideration of a long round trip delay between a terminal and a base station in the above-described non-ground network situation will be described in detail. Each of the embodiments provided below can be implemented individually or by any combination.

For convenience of description, hereinafter, a timer processing processing method and a random access procedure considering a long round trip delay of NTN on a DRX procedure will be mainly described. This is for convenience of description, and the embodiment described below may be applied to timer processing on any MAC procedure. In addition, in the following, for convenience of understanding, it will be described as a base station.

First embodiment: A method of linking a new parameter for indicating a long round trip delay offset value by designating a specific value of an existing parameter

In order to consider a long propagation delay situation of a non-terrestrial network, a value applied to a parameter used in a MAC procedure can be configured to be distinguished from a terrestrial network.

For example, in order to consider a large propagation delay of a non-terrestrial network, a value applied to a parameter included in the DRX configuration information element may be configured with a large value. For example, a value that can be assigned to drx-HARQ-RTT-Timer or drx-RetransmissionTimer included in the configuration information can be controlled to be configured to a value exceeding the round trip delay of the non-ground network. To this end, the configurable value for each parameter can be changed / added, or a specific value can be designated to indicate the associated parameter. For a terminal capable of communication using a non-terrestrial network (NTN capable terminal), a parameter value composed of a value exceeding the round trip delay may be used.

As a specific example, the base station divides the drx-HARQ-RTT-Timer value from the existing 0 to 56 symbols according to the type of the non-terrestrial network (for example, LEO satellite, MEO satellite, GEO satellite, HAPs, etc.). The round trip delay offset value can be selected and added. A terminal capable of non-terrestrial network communication (a terminal having NTN capabilities) may perform a DRX operation through an added value. When considering the long round trip delay of the satellite, a value added to the 0 to 56 symbol may be a unit other than a symbol unit (for example, a slot or ms (millisecond)). For example, it is assumed that for a specific LEO satellite, within the coverage by the NTN cell or NTN beam provided by the satellite, the round trip delay between the terminal of the cell / beam center point and the satellite is 24 ms. The round trip delay may vary depending on the location of the terminal and the location of the satellite. Therefore, the round trip delay between the terminal of the cell / beam center point and the satellite within coverage by the NTN cell / beam provided by the above-described satellite is defined as a reference (reference) round trip delay. For convenience of description, the reference round trip delay will be described below. The base station may allow the drx-HARQ-RTT-Timer to select an integer value from INTEGER (reference round trip delay .... reference round trip delay + 56). Here, a value converted in units of slots may be used for the round trip delay. Accordingly, the drx-HARQ-RTT-Timer value may be selected and indicated from an integer value between a reference round trip delay value and 56 slots added to the reference round trip delay value. Alternatively, for this, the base station may indicate the reference round trip delay to the terminal through a separate information element. In this case, the terminal indicates the drx-HARQ-RTT-Timer parameter as an integer value between 0 and 56 slots as in the prior art, and adds the reference round trip delay to the NTN capable terminal drx-HARQ-RTT-Timer It can be used as a value.

As another specific example, the base station sets the drx-HARQ-RTT-Timer value from a conventional 0 to 56 symbol to a typical round trip according to the type of a non-terrestrial network (for example, LEO satellite, MEO satellite, GEO satellite, HAPs, etc.). Code the delay value. The base station can select one of the coded values and replace 0 to 56 symbol values. A terminal capable of non-ground network communication may perform a DRX operation through a changed value. The value may be coded based on a value selected through a unit other than a symbol unit (for example, a slot or ms). A base station supporting a non-terrestrial network may indicate a corresponding value to the terminal through explicit signaling through system information or dedicated RRC signaling. Alternatively, the terminal may be configured to use the corresponding value implicitly according to other indication information or pre-configuration by the base station supporting the non-terrestrial network.

As another specific example, the base station may indicate a parameter to be used as a drx-HARQ-RTT-Timer for NTN by designating a specific value (eg, 0) among the conventional drx-HARQ-RTT-Timer values. have. In a terminal capable of non-terrestrial network communication, when drx-HARQ-RTT-Timer is indicated with a corresponding value (for example, 0), a parameter value indicated by information distinguished from drx-HARQ-RTT-Timer (Information element) Can be used as HARQ-RTT-Timer. A parameter distinguished from drx-HARQ-RTT-Timer to be used as HARQ-RTT-Timer may be indicated as system information or RACH-common information (RACH-configcommon). Alternatively, a parameter distinguished from drx-HARQ-RTT-Timer to be used as HARQ-RTT-Timer may be indicated to be used in connection with each drx parameter in drx-config. Alternatively, the parameter value distinguished from drx-HARQ-RTT-Timer to be used as HARQ-RTT-Timer may be calculated by the terminal by separate information explicitly or implicitly indicated by the base station. The parameter distinguished from drx-HARQ-RTT-Timer to be used as HARQ-RTT-Timer may be provided as a time value such as one way delay or RTD between the terminal and the base station, and coded according to the location or height information of the base station to reference round It may be provided as a value used to recognize / calculate the trip delay.

As another specific example, the base station sets the drx-RetransmissionTimer value to a value considering the typical round trip delay value according to the type of the non-terrestrial network (for example, LEO satellite, MEO satellite, GEO satellite, HAPs, etc.), and the spare value. Can be added to Alternatively, the above-described drx-HARQ-RTT-Timer embodiments may be applied to the drx-RetransmissionTimer in the same form. Alternatively, the drx-HARQ-RTT-Timer is set to a separate value for the non-terrestrial network according to each of the above-described embodiments, but the drx-RetransmissionTimer value is used in the terrestrial network situation to reduce the monitoring time of the PDCCH of the terminal. The range of parameter values of the conventional NR may be equally applied.

As described above, the non-terrestrial network may have various types according to network node types such as GEO, MEO, LEO, and HAPS, and the altitude of satellites may be operated differently within each type. Meanwhile, the DRX parameter on the NR RRC standard is set and standardized with a value within a predetermined range. The drx-HARQ-RTT-Timer parameter value described above may be indicated to the UE with a range of different DRX parameters for each NTN type / satellite altitude / round trip delay in order to consider various round trip delays of NTN. Alternatively, the drx-HARQ-RTT-Timer parameter value has a range of one DRX parameter and may be instructed to be applied in conjunction with a reference round trip delay. Alternatively, the drx-HARQ-RTT-Timer parameter value may be indicated through a specific value of an existing parameter.

Second embodiment: A method of instructing the terminal to offset information for a non-terrestrial network and overriding or adding the value of the offset information to a corresponding timer value.

Offset information may be configured to account for a large propagation delay of a non-terrestrial network. In addition, the offset information may be added / subtracted / calculated to an arbitrary drx timer value, or may be used by replacing the offset information with an arbitrary drx timer value. For convenience of description, this is referred to as a round trip delay offset or NTN RTD offset. This is for convenience of description and may be replaced with any other name, and may refer to the reference round trip delay described above.

For example, when a terminal capable of non-terrestrial network communication receives NTN RTD offset information (or information for calculating it), a value of drx-HARQ-RTT-Timer (or drx-RetransmissionTimer) indicated through DRX configuration information is received. Control the running of drx-HARQ-RTT-Timer (or drx-RetransmissionTimer) with NTN RTD offset plus. Alternatively, the terminal capable of non-terrestrial network communication ignores the value set in drx-HARQ-RTT-Timer (or drx-RetransmissionTimer) and receives NTN RTD offset when NTN RTD offset information (or information for indicating it) is received. Can be used to control the running of drx-HARQ-RTT-Timer (or drx-RetransmissionTimer)

As a specific example, when the NTN RTD offset is configured to 544ms, when the drx-HARQ-RTT-Timer value is configured to 56 symbols (4ms assuming the use of 15kHz subcarrier spacing), the terminal is 548ms (544ms + 4ms) Drx-HARQ-RTT-Timer can expire when.

As another specific example, when the NTN RTD offset is configured to 544 ms, if the drx-HARQ-RTT-Timer value is configured to 56 symbols (if 4 ms is assumed when using 15 kHz subcarrier spacing), the UE is directed to the indicated drx-HARQ- The RTT-Timer value (4ms) can be ignored and the drx-HARQ-RTT-Timer value can be used by applying / calculated the value (544ms) indicated by the NTN RTD offset. For example, the terminal may use the corresponding value (544 ms) as the drx-HARQ-RTT-Timer value, if the NTN RTD offset is indicated (or if the NTN RTD offset is calculated according to the indication information).

As another specific example, even if the NTN RTD offset is configured to 544ms, drx-RetransmissionTimer may use a value indicated by drx-RetransmissionTimer through DRX configuration information. For example, a terminal configured with a drx-RetransmissionTimer value of 8 slots (if assumed to use 15 kHz subcarrier spacing, 8 ms) can start the corresponding timer and expire drx-RetransmissionTimer when it reaches 8 ms. In this case, the drx-HARQ-RTT-Timer value may be changed by applying an NTN RTD offset according to the specific embodiment described above.

As another specific example, when the NTN RTD offset is configured to 544 ms, a terminal configured with a drx-RetransmissionTimer value of 8 slots (8 ms, assuming 15 kHz subcarrier spacing is used) expires drx-RetransmissionTimer when 544 ms + 8 ms. can do.

Operation on the MAC entity side may be performed by the following procedure.

As an example, when DRX is configured, the MAC entity is

> If one MAC PDU is sent from one configured uplink grant:

>> After the end of the first iteration of the corresponding PUSCH transmission, drx-HARQ-RTT-TimerUL for the HARQ process corresponding to the first symbol is started;

>> Stop drx-RetransmissionTimerUL for the corresponding HARQ process.

> If one drx-HARQ-RTT-TimerDL expires:

>> If the data of the corresponding HARQ process has not been successfully decoded:

>>> After expiration of drx-HARQ-RTT-TimerDL, drx-RetransmissionTimerDL for the HARQ process corresponding to the first symbol starts.

> If one drx-HARQ-RTT-TimerUL expires:

>> After the expiration of drx-HARQ-RTT-TimerUL, drx-RetransmissionTimerUL for the HARQ process corresponding to the first symbol is started.

> If the MAC entity is in active time:

>> Monitor the PDCCH.

>> If the PDCCH indicates one DL transmission or if one DL allocation is configured:

>>> Starts drx-HARQ-RTT-TimerDL for the HARQ process corresponding to the first symbol after the end of the corresponding PUCCH transmission;

>>> Stop drx-RetransmissionTimerDL for the corresponding HARQ process.

>> If PDCCH indicates one UL transmission:

>>> Starts drx-HARQ-RTT-TimerUL for the HARQ process corresponding to the first symbol after the end of the first iteration of the corresponding PUSCH transmission;

>>> Stop drx-RetransmissionTimerUL for the corresponding HARQ process.

Meanwhile, when one DRX cycle is configured, the active time for a terminal capable of non-terrestrial network communication includes one or more of the following.

-drx-RetransmissionTimerUL is active and active time when drx-RetransmissionTimerUL is greater than (or greater than or equal to) the NTN RTD offset.

-drx-RetransmissionTimerDL is active and active time when drx-RetransmissionTimerDL is greater than (or greater than or equal to) the NTN RTD offset.

-ra-ContentionResolutionTimer is active and active time when ra-ContentionResolutionTimer is greater than (or equal to) the NTN RTD offset.

-NTN RTD offset has elapsed since one scheduling request is transmitted on PUCCH and is pending or if sr-ProhibitTimer is configured and used to prohibit duplicate scheduling requests, one scheduling request has been transmitted on PUCCH and sr- ProhibitTimer is greater than (or equal to or greater than) the NTN RTD offset and is active time when pending.

-NTN RTD offset elapsed after successful reception of one random access response to a random access preamble not selected by the MAC entity during content-based random access preamble and indicates one new transmission addressed to the C-RNTI of the MAC entity This is the active time when the PDCCH is not successfully received.

DRX is configured, and if the MAC entity is at the aforementioned active time, the MAC entity monitors the PDCCH.

Accordingly, the UE can reduce power consumption by sending a scheduling request and monitoring the PDCCH immediately after the round trip delay without monitoring the PDCCH immediately.

The aforementioned offset information or the offset timer, which will be described later, may be indicated as system information or RACH common information (RACH-configcommon). Alternatively, the offset information or the offset timer, which will be described later, may be indicated in drx-config in connection with each drx parameter. Alternatively, the offset information or the offset timer, which will be described later, may be explicitly indicated by an arbitrary signal by the base station. Alternatively, the offset information or the offset timer, which will be described later, may be calculated by a terminal capable of non-ground network communication through explicitly indicated information and pre-configured information. The offset information or the offset timer, which will be described later, may be provided as a time value such as one way delay or RTD between the terminal and the base station, or may be coded according to the location or height information of the base station and provided as a value to recognize / calculate the RTD. have. Alternatively, the information indicated by the base station includes information (for example, index value TA) used to control the amount of timing adjustment in the MAC entity, and offset information or an offset timer to be described later is calculated through operation of the indicated information. It might be.

Third embodiment: A method of indicating a new offset timer different from an existing timer.

A new timer for considering a large propagation delay of a non-terrestrial network may be defined and configured in the terminal. For convenience of explanation, this is referred to as an offset timer, but in order to effectively support non-terrestrial network communication of the terminal, it may be replaced with an arbitrary name by indicating any new timer added separately on the existing MAC procedure. For example, when a terminal capable of non-terrestrial network communication receives an offset timer (or information for calculating it), it may start a corresponding timer and start drx-HARQ-RTT-Timer or drx-RetransmissionTimer after it expires. As another example, when the drx-HARQ-RTT-Timer or drx-RetransmissionTimer expires, an offset timer may be started.

For example, when the offset timer is configured to 544ms, if the drx-HARQ-RTT-Timer is configured with 56 symbols (4ms, assuming the use of 15kHz subcarrier spacing), the terminal drx-HARQ-RTT- in the prior art Start the first offset timer when the timer needs to be started. When the first offset timer expires after 544 ms, the terminal starts drx-HARQ-RTT-Timer. Through this, the terminal may start drx-HARQ-RTT-Timer in consideration of the offset round trip delay in a non-ground network situation.

As another example, when the offset timer is configured to 544ms, when the drx-HARQ-RTT-Timer is configured with 56 symbols (4ms if using 15kHz subcarrier spacing), the UE is directed to the indicated drx-HARQ-RTT-Timer The value (4ms) can be ignored and the drx-HARQ-RTT-Timer value can be used (overriding) the value (544ms) indicated / calculated by the NTN RTD offset. For example, if an NTN RTD offset is indicated (or an NTN RTD offset is calculated according to the indication information), the corresponding value (544 ms) may be used as a drx-HARQ-RTT-Timer value. In this case, since the offset timer value is reflected in the drx-HARQ-RTT-Timer value, the operation of drx-HARQ-RTT-Timer can be applied in the same way as the conventional method using a terrestrial network.

As another example, regardless of the offset timer configured to 544 ms, drx-RetransmissionTimer may be operated according to a value indicated by drx-RetransmissionTimer. For example, if the drx-RetransmissionTimer value is configured with 8 slots (8ms if using 15kHz subcarrier spacing), the UE can start drx-RetransmissionTimer and expire drx-RetransmissionTimer when it reaches 8ms.

As another example, when the offset timer is configured to 544ms, when the drx-RetransmissionTimer value is configured to 8 slots (8ms if assumed to use 15kHz subcarrier spacing), when the terminal needs to start drx-RetransmissionTimer in the prior art Start the second offset timer. When the second offset timer expires after 544 ms, the terminal starts drx-RetransmissionTimer.

Meanwhile, the DRX operation in terms of the operation of the MAC entity is as follows.

When DRX is configured, the MAC entity

> If one MAC PDU is received in one configured downlink assignment:

>> DL Starts the offset timer for the HARQ process corresponding to the first symbol after the end of the corresponding transport carrying HARQ feedback.

>> Stop drx-RetransmissionTimerDL for the corresponding HARQ process.

> If the offset timer expires:

>> Start drx-HARQ-RTT-TimerDL for the corresponding HARQ process;

>> Stop drx-RetransmissionTimerDL for the corresponding HARQ process.

> If one drx-HARQ-RTT-TimerDL expires:

>> If the data of the corresponding HARQ process has not been successfully decoded:

>>> After the expiration of drx-HARQ-RTT-TimerDL, an offset timer for the HARQ process corresponding to the first symbol starts.

>> If the offset timer expires:

>>> Start drx-RetransmissionTimerDL for the corresponding HARQ process.

(Or, if one drx-HARQ-RTT-TimerDL expires:

>> If the data of the corresponding HARQ process has not been successfully decoded:

>>> After expiration of drx-HARQ-RTT-TimerDL, drx-RetransmissionTimerDL for the HARQ process corresponding to the first symbol is started.)

> If one drx-HARQ-RTT-TimerUL expires:

>> After the expiration of drx-HARQ-RTT-TimerUL, start an offset timer for the HARQ process corresponding to the first symbol.

>> If the offset timer expires:

>>> Start drx-RetransmissionTimerUL for the corresponding HARQ process.

(Or,> If one drx-HARQ-RTT-TimerUL expires:

>> After the expiration of drx-HARQ-RTT-TimerUL, drx-RetransmissionTimerUL for the HARQ process for the HARQ process corresponding to the first symbol is started.)

> If the MAC entity is in active time:

>> Monitor the PDCCH.

>> If the PDCCH indicates one DL transmission (or if one DL allocation is configured):

>>> After the end of the corresponding PUCCH transmission (DL HARQ feedback), the offset timer for the HARQ process corresponding to the first symbol is started or restarted.

>>> Stop drx-RetransmissionTimerDL for the corresponding HARQ process.

>> When the offset timer expires

>>> Start drx-HARQ-RTT-TimerDL for the corresponding HARQ process;

>>> Stop drx-RetransmissionTimerDL for the corresponding HARQ process.

>> If PDCCH indicates one UL transmission:

>>> Start the offset timer for the HARQ process corresponding to the first symbol after the end of the first iteration of the corresponding PUSCH transmission;

>> When the offset timer expires

>>> Start drx-HARQ-RTT-TimerUL for the corresponding HARQ process.

MAC entity operation according to another example is as follows.

As another example, when DRX is configured, the MAC entity is

> If one MAC PDU is received in one configured downlink assignment:

>> Starts drx-HARQ-RTT-TimerDL for the HARQ process corresponding to the first symbol after the indicated offset time elapses from the end of the corresponding transmission carrying DL HARQ feedback.

>> Stop drx-RetransmissionTimerDL for the corresponding HARQ process.

> If the MAC entity is in active time:

>> Monitor the PDCCH.

>> If the PDCCH indicates one DL transmission (or if one DL allocation is configured):

>>> DL Starts or restarts drx-HARQ-RTT-TimerDL for the HARQ process corresponding to the first symbol after the specified offset time elapses from the end of the corresponding transmission carrying HARQ feedback.

The operation of DRX parameters such as the HARQ-RTT Timer and drx-RetransmissionTimer described in the above-described embodiments has been described based on a general situation in which the HARQ process operates. However, due to the long distance between the terminal and the network node in a non-terrestrial network situation, when the NTN provides the NR HARQ procedure as it is, the packet may be delayed (HARQ stalling) in the error correction process through the HARQ. For example, if the HARQ operation is performed through 16 parallel HARQ processes provided by NR, a packet may be delayed (HARQ stalling) in an error correction process through HARQ. In addition, it is difficult to increase the number of HARQ processes because an additional cost is required for the UE to increase the number of HARQ processes.

In order to solve this problem, the HARQ operation (eg, HARQ feedback for downlink reception) may be disabled for each HARQ process while maintaining the number of HARQ processes. For convenience of description, this is referred to as HARQ feedback disable. This is for convenience of description and may be replaced with an arbitrary name that means a form in which HARQ is not operated, such as HARQ disable, HARQ deactivation, no Uplink HARQ feedback, and HARQ feedback disable in the UE for downlink transmission.

The aforementioned drx-HARQ-RTT-Timer starts when the terminal transmits HARQ NACK feedback to the base station. While the drx-HARQ-RTT-Timer is operating, the UE does not expect downlink allocation or uplink grant reception for the corresponding HARQ process. If HARQ feedback is disabled, drx-HARQ-RTT-Timer can also be disabled for the corresponding HARQ process. In this case, since the drx-HARQ-RTT-Timer is not started for the corresponding HARQ process, the terminal also does not start drx-RetransmissionTimer for the corresponding HARQ process.

Meanwhile, even when HARQ feedback is disabled, the base station can perform blind repetitive transmission to increase transmission reliability. For example, the base station may perform multiple transmissions (e.g. MAC schedules packets in a bundle with pdsch-AggregationFactor> 1 in down link) of the same transport block (TB) as a bundle. In addition, the terminal may soft combine multiple transmissions of the same TB in a bundle. As another example, the base station may perform multiple transmissions of the same transport block (TB) (e.g. MAC schedules the same TB on the same HARQ process without NDI being toggled). And the terminal can soft combine multiple transmissions of the same TB.

If the base station wants to lower the BLER through (blind) repetitive transmission, the UE and the base station can reduce the power consumption by performing PDCCH monitoring by aligning the expected time for repetitive transmission.

To this end, when HARQ feedback is disabled, the base station may indicate information for repetitive transmission to the terminal. Alternatively, when HARQ feedback is disabled, the UE can expect repetitive transmission by monitoring the PDCCH using the existing DRX parameter.

For example, the UE may monitor the PDCCH for a time period during which repeated transmission is expected using the drx-RetransmissionTimer parameter. For example, HARQ feedback is disabled, if the PDCCH indicates downlink transmission, and if the data of the corresponding HARQ process has not been successfully decoded, the terminal (MAC entity) starts drx-RetransmissionTimer.

For another example, a new DRX parameter defining a maximum duration until repetitive transmission is received is defined, so that the UE can monitor the PDCCH for a time period during which repetitive transmission is expected. When the DRX cycle is configured, the terminal may be included in the active time while the timer according to the newly defined DRX parameter is operating. For example, HARQ feedback is disabled, if the PDCCH indicates downlink transmission, and if the data of the corresponding HARQ process has not been successfully decoded, the terminal (MAC entity) starts the corresponding timer.

On the other hand, if HARQ feedback is disabled, the base station can always transmit data by instructing a new transmission through the PDCCH, unless the case of blind repeated transmission. In this case, the terminal (the MAC entity of the terminal) starts or restarts the DRX inactivity timer ( drx-InactivityTimer ) in the first symbol after the end of the PDCCH reception. Alternatively, even in the case of repetitive transmission other than new transmission, if the PDCCH indicates downlink (or uplink) transmission, the UE starts or restarts the DRX activity timer ( drx-InactivityTimer ). Alternatively, in the case of repetitive transmission other than new transmission, the PDCCH instructs downlink (or uplink) transmission, and if the data of the corresponding HARQ process is not successfully decoded, the UE sends a DRX inactivity timer ( drx-InactivityTimer ). Start or restart. The base station can monitor the PDCCH in accordance with the time for the terminal and the blind repetitive transmission by setting and instructing the DRX inactivity timer to a non-zero value.

Or, it may not be desirable from a power consumption point of view to allow the terminal to always monitor the PDCCH in anticipation of repetitive transmission. Therefore, if the base station disables HARQ feedback of the terminal and performs repetitive transmission to lower the BLER, the base station may transmit indication information for instructing the terminal to perform the operation accordingly. For example, the indication information may be provided through RRC signaling. For another example, the indication information may be provided through MAC CE signaling. For another example, the indication information may be provided through DCI. The RRC signaling, MAC CE, or DCI described above may further include at least one of HARQ process ID and information indicating activation / deactivation status of repetitive transmission.

In addition, the terminal may transmit help information to help determine the number of repetitive transmissions of the base station to the base station. The help information may include at least one of HARQ reception failure rate and request repetition transmission number information.

Application examples for other MAC procedures

As described above, each of the embodiments described above can be applied to any MAC procedure such as a random access procedure as well as HARQ operation. In order to explain in more detail, a random access procedure or a scheduling request procedure among arbitrary MAC procedures is exemplarily described below.

The random access procedure may be a contention based random access procedure as described in FIG. 6. The 4-step procedure is performed with the MS's random access preamble transmission as MSG1, the base station's random access response transmission (RAR) as MSG2, the uplink grant included in RAR as MSG3, and the contention resolution as MSG4. do.

The following parameters are defined in Contention based random access.

-ra-ResponseWindow : the time window to monitor the random access response (the time window to monitor RA response (s) (SpCell only))

-ra -ContentionResolutionTimer : Timer for resolving competition (the Contention Resolution Timer (SpCell only))

When the random access preamble is transmitted, the MAC entity operates as follows.

From the end of the random access preamble transmission, a ra-ResponseWindow configured in RACH-ConfigCommon is started in the first PDCCH okay specified in TS 38.213.

 While the ra-ResponseWindow is running, it monitors the SpCell's PDCCH for a random access response identified by the RA-RNTI.

 If the ra-ResponseWindow configured in RACH-ConfigCommon has expired, and if a random access response including a random access preamble matching the transmitted PREAMBLE_INDEX has not yet been received (if ra-ResponseWindow configured in RACH-ConfigCommon expires, and if the Random Access Response containing Random Access Preamble identifiers that matches the transmitted PREAMBLE_INDEX has not been received; or

If ra-ResponseWindow configured in BeamFailureRecoveryConfig expires and if the PDCCH addressed to the C-RNTI has not been received :,), it is considered that the reception of the random access response is not successful. The MAC entity increases PREAMBLE_TRANSMISSION_COUNTER by 1.

When Msg3 is transmitted, the MAC entity operates as follows.

start the ra-ContentionResolutionTimer and restart the ra-ContentionResolutionTimer at each HARQ retransmission in the first symbol after the end of the Msg3 transmission)

When the ra-ContentionResolutionTimer is running, the UE monitors the PDCCH. (monitor the PDCCH while the ra-ContentionResolutionTimer is running regardless of the possible occurrence of a measurement gap;) When the ra-ContentionResolutionTimer expires, it is considered that the competition is not successful do.

The embodiment linked to a new parameter for indicating a long round trip delay value by designating a specific value of an existing parameter described in the first embodiment can be applied to the above random access procedure by changing only the parameter.

As described in the second embodiment, the base station indicates the offset information, and the offset information can be used by overriding or adding / subtracting / calculating with ra-ResponseWindow or ra-ContentionResolutionTimer. Alternatively, as in the second embodiment described above, a separate offset timer may be configured and operated.

For example, the base station may configure offset information to consider a large propagation delay of a non-terrestrial network in the terminal. And the terminal may add the offset information to a random access timer value or use the offset information as a random access timer value. For example, when a terminal capable of non-terrestrial network communication receives NTN RTD offset information (or information for calculating it), a window or timer up to the value assigned to ra-ResponseWindow or ra-ContentionResolutionTimer plus the NTN RTD offset is added. It can be run. Alternatively, when a terminal capable of non-terrestrial network communication receives NTN RTD offset information (or information for indicating it), the value assigned to ra-ResponseWindow or ra-ContentionResolutionTimer is ignored and ra-ResponseWindow or ra using NTN RTD offset -You can run ContentionResolutionTimer.

As an example, when the NTN RTD offset is configured to 544 ms, when the ra-ResponseWindow is configured with 4 slots (4 ms if using 15 kHz subcarrier spacing), the terminal will expire the ra-ResponseWindow when it becomes 544 ms + 4 ms. You can.

As another example, when the NTN RTD offset is configured to 544 ms, if the ra-ResponseWindow is configured with 4 slots (4 ms if using 15 kHz subcarrier spacing), the UE ignores the indicated ra-ResponseWindow value (4 ms). The ra-ResponseWindow value can be used by overriding the value indicated / calculated by the NTN RTD offset (544 ms). For example, if the NTN RTD offset is indicated (or if the NTN RTD offset is calculated according to the indication information), the UE may use the corresponding value (544 ms) as a ra-ResponseWindow value.

As another example, regardless of the NTN RTD offset configured to 544ms, ra-ContentionResolutionTimer can use the value assigned to ra-ContentionResolutionTimer. For example, if the ra-ContentionResolutionTimer value is composed of 8 subframes (8ms if assumed to use 15kHz subcarrier spacing), the UE can start the corresponding timer and expire ra-ContentionResolutionTimer when it reaches 8ms.

As another example, when the NTN RTD offset is configured to 544ms, and the ra-ContentionResolutionTimer value is configured to 8 subframes (8ms if 15kHz subcarrier spacing is used), the UE ra-ContentionResolutionTimer when 544ms + 8ms Can expire.

The operation from the MAC entity point of view is as follows.

Start ra-ResponseWindow on the first PDCCH occurrence specified in TS 38.213 from the end of the random access preamble transmission.

> Monitor the SpCell's PDCCH for a random access response identified by the RA-RNTI while the ra-ResponseWindow is running.

(Or while> ra-ResponseWindow is running,

If ra-ResponseWindow is less than (or less than or equal to) the NTN RTD offset, the MAC entity does not monitor the SpCell's PDCCH for the random access response identified by the RA-RNTI.

If ra-ResponseWindow is greater than or equal to (or greater than) the NTN RTD offset, the MAC entity monitors the SpCell's PDCCH for a random access response identified by the RA-RNTI.)

> If the ra-ResponseWindow configured in RACH-ConfigCommon has expired, and a random access response including a random access preamble matching the transmitted PREAMBLE_INDEX has not yet been received (if ra-ResponseWindow configured in RACH-ConfigCommon expires, and if the Random Access Response containing Random Access Preamble identifiers that matches the transmitted PREAMBLE_INDEX has not been received; or

If ra-ResponseWindow configured in BeamFailureRecoveryConfig expires and if the PDCCH addressed to the C-RNTI has not been received :,) it is considered that the reception of the random access response is not successful.

> PREAMBLE_TRANSMISSION_COUNTER is increased by 1.

Meanwhile, when Msg3 is transmitted, the MAC entity operates as follows.

start the ra-ContentionResolutionTimer and restart the ra-ContentionResolutionTimer at each HARQ retransmission in the first symbol after the end of the Msg3 transmission)

Monitor the PDCCH while ra-ContentionResolutionTimer is running (monitor the PDCCH while the ra-ContentionResolutionTimer is running regardless of the possible occurrence of a measurement gap;) When ra-ContentionResolutionTimer expires, content resolution is considered unsuccessful do. If ra-ContentionResolutionTimer is less than (or less than or equal to) the NTN RTD offset, the MAC entity does not monitor the PDCCH. If ra-ContentionResolutionTimer is greater than or equal to (or greater than) the NTN RTD offset, the MAC entity monitors the PDCCH. If the contention resolution is considered to be successful (for example, if the PDCCH transmission is addressed to C-RNTI or the terminal contention resolution identifier matches the CCCH SDU transmitted in Msg3), the ra-ContentionResolutionTimer is stopped.

Meanwhile, the operation of the above-described third embodiment may be applied.

For example, in order to consider a large propagation delay of a non-terrestrial network, an offset timer distinct from the existing timer may be indicated. For example, when a terminal capable of non-terrestrial network communication receives an offset timer (or information for calculating it), it starts the corresponding timer and starts ra-ResponseWindow or ra-ContentionResolutionTimer after the offset timer expires. Alternatively, when a terminal capable of non-terrestrial network communication receives offset information, ra-ResponseWindow or ra after the offset has elapsed since the start condition of ra-ResponseWindow or ra-ContentionResolutionTimer is satisfied (eg MSG1 transmission or MSG3 transmission). -ContentionResolutionTimer can also be started.

For example, when the offset timer (or offset information) is configured to 544ms, if ra-ResponseWindow is configured with 4 slots (4ms if using 15kHz subcarrier spacing), the terminal must start ra-ResponseWindow in the prior art. When (for example, random access preamble transmission), the third offset timer starts. When the third offset timer expires after 544 ms, the terminal starts ra-ResponseWindow.

As another example, when the offset timer is configured to 544ms, if ra-ResponseWindow is configured with 4 slots (4ms if using 15kHz subcarrier spacing), the UE ignores the indicated ra-ResponseWindow value (4ms) and ra -ResponseWindow value can be used by overriding the value indicated / calculated by NTN RTD offset (544ms). For example, if the NTN RTD offset is indicated (or if the NTN RTD offset is calculated according to the indication information), the UE may use the corresponding value (544 ms) as a ra-ResponseWindow value. In this case, the ra-ResponseWindow can operate in accordance with the prior art to provide the same effect.

As another example, when the offset timer is configured to 544ms, if the ra-ContentionResolutionTimer value is configured to 8 subframes (8ms, assuming 15kHz subcarrier spacing is used), the UE sets the indicated ra-ContentionResolutionTimer value (8ms). It can be ignored and used by overriding the ra-ContentionResolutionTimer value with the value indicated / calculated by the NTN RTD offset (544ms).

As another example, when the offset timer is configured to 544ms, ra-ContentionResolutionTimer may use the value indicated by ra-ContentionResolutionTimer as it is. For example, if the ra-ContentionResolutionTimer value is configured with 8 slots (8ms if using 15kHz subcarrier spacing), the UE starts the ra-ContentionResolutionTime timer after the offset timer expires and ra-ContentionResolutionTimer when it reaches 8ms. Can expire. .

As another example, when the offset timer is configured to 544ms, when the ra-ContentionResolutionTimer value is configured to 8 subframes (8ms if assumed to use 15kHz subcarrier spacing), the terminal must start the ra-ContentionResolutionTimer set in the prior art. When (for example, MSG3 transmission) starts the fourth offset timer. When the fourth offset timer expires after 544 ms, the UE starts ra-ContentionResolutionTimer. The ra-ContentionResolutionTimer expires after 8ms.

Meanwhile, when the random access preamble is transmitted, the MAC entity operates as follows.

Start a third offset timer from the end of the random access preamble transmission to the first PDCCH okay specified in TS 38.213.

>> When the 3rd offset timer expires, start ra-ResponseWindow (or start ra-ResponseWindow in the first PDCCH ok after the offset elapses at the end of random access preamble transmission).

>> While the ra-ResponseWindow is running, the PDCCH of SpCell is monitored for a random access response identified by RA-RNTI.

>> If ra-ResponseWindow configured in RACH-ConfigCommon expires, and if a random access response including a random access preamble matching the transmitted PREAMBLE_INDEX has not yet been received (if ra-ResponseWindow configured in RACH-ConfigCommon expires, and if the Random Access Response containing Random Access Preamble identifiers that matches the transmitted PREAMBLE_INDEX has not been received; or

If ra-ResponseWindow configured in BeamFailureRecoveryConfig expires and if the PDCCH addressed to the C-RNTI has not been received :,) it is considered that the reception of the random access response is not successful.

>> PREAMBLE_TRANSMISSION_COUNTER is increased by 1.

In addition, when Msg3 is transmitted, the MAC entity operates as follows.

> Start the fourth offset timer.

>> When the fourth offset timer expires, start (or restart) ra-ContentionResolutionTimer (or start ra-ContentionResolutionTimer in the first PDCCH occlusion after the offset elapses at the end of Msg3 transmission).

>> monitor PDCCH while ra-ContentionResolutionTimer is running (monitor the PDCCH while the ra-ContentionResolutionTimer is running regardless of the possible occurrence of a measurement gap;)

If the >> ra-ContentionResolutionTimer expires, consider that content resolution is unsuccessful.

>> Flush HARQ buffer used for MAC PDU transmission in Msg3 buffer.

>> Increase the preamble transmission counter by 1.

>> If content resolution is considered to be successful (e.g., if PDCCH transmission is addressed to C-RNTI or if the terminal contention resolution identifier matches the CCCH SDU transmitted in Msg3), then stop ra-ContentionResolutionTimer .

As described above, the contention-based random access procedure controls the timer operation in the random access procedure in consideration of the reference round trip delay offset.

16 is a diagram for explaining a timer control operation in a contention-based random access situation according to an embodiment.

Referring to FIG. 16, a terminal performing a random access procedure to access a non-terrestrial network cell starts a timer for contention cancellation after a time period corresponding to a reference round trip delay offset after transmitting MSG 3. Thereafter, when MSG 4 is normally received, the terminal stops a timer for resolving contention. If the timer for contention resolution expires before MSG 4 is received, the UE determines that the random access procedure has failed.

As described above, the method of operating the timer by reflecting the reference round trip delay offset is performed in various aforementioned manners such as the existing timer value reflects offset information or operates a separate offset timer as in the first to third embodiments. Yes can be applied.

Meanwhile, the embodiment reflection operation in the above-described random access procedure may be applied to a two-step random access procedure. The two-step random access procedure is a simplified two-step existing 4-step random access procedure. Since 4 steps are reduced to 2 steps, an effect of reducing the delay of the random access process can be expected. Therefore, it may be desirable to use it for non-terrestrial communication. However, in order to support 2-step random access, the terminal must transmit MSG1 (or random access preamble) and MSG3 (or information included in MSG3, for example, CCCH SDU) of the existing 4-step random access procedure at a time / concurrently based on contention. Therefore, more resources can be wasted in case of competition or failure. Therefore, it may be desirable for the two-step random access to be selectively configured by the base station. Basically, it can be assumed that the 2-step random access includes transmission of the MSG1 and MSG3 of the 4-step random access to the content-based resource in step 1. In addition, it may be assumed that information included in MSG2 and MSG4 of the 4-step random access in steps 2 is received.

At this time, if the above-described ra-ResponseWindow and / or ra-ContentionResolutionTimer or a new timer is defined, the above-described first to third embodiments may be applied to the corresponding parameter. For convenience of description, a message including the contents of MSG1 and MSG3 is defined as MsgA, and a message including the contents included in MSG2 and MSG4 is defined as MsgB. For example, MsgA may transmit a PRSCH preamble and a PUSCH including a CCCH SDU together.

The above-described operation will be described with reference to the operation of the MAC entity in the 2-step random access procedure.

When the MsgA is transmitted, the MAC entity operates as follows.

> Start the fifth offset timer.

>> When the fifth offset timer expires, a two-step RACH response window (or a two-step RACH timer) is started (or a two-step RACH response window (or two-step) to the first PDCCH occlusion after the offset elapses at the end of MsgA transmission. RACH timer).

>> Monitor the PDCCH while the 2-step RACH response window (or 2-step RACH timer) is running.

When the 2-step RACH response window (or 2-step RACH timer) expires, consider that the content resolution is unsuccessful.

>> Flush HARQ buffer used for MAC PDU transmission in MsgA buffer.

>> Increase the preamble transmission counter by 1.

>> If content resolution is considered to be successful (e.g., if PDCCH transmission is addressed to C-RNTI or if the terminal contention resolution identifier matches the CCCH SDU transmitted in MsgA), the 2-step RACH response window ( Or 2 step RACH timer).

17 is a diagram for explaining a timer control operation in a two-step random access situation according to an embodiment.

Referring to FIG. 17, a terminal performing a random access procedure to access a non-terrestrial network cell starts a response timer after a time period corresponding to a reference round trip delay offset after transmitting MSG A. Thereafter, when the MSG B is normally received, the terminal stops the response timer. If the timer for resolving contention expires before MSG B is received, the UE determines that the random access procedure has failed. Here, the response timer may mean the above-described two-step RACH response window or two-step RACH timer.

As described above, the method of operating the timer by reflecting the reference round trip delay offset is performed in various aforementioned manners such as the existing timer value reflects offset information or operates a separate offset timer as in the first to third embodiments. Yes can be applied.

Hereinafter, a case where the present embodiment is applied to a scheduling request (SR) procedure will be described as an example.

The scheduling request is used for UL-SCH resource request for new transmission. When the SR is transmitted, the MAC entity of the UE monitors the PDCCH in order to receive the scheduling grant from the base station, and it is also undesirable in terms of power consumption to continuously monitor the PDCCH under a large delay of a non-terrestrial network. Therefore, the above-described embodiments may be applied to the scheduling request procedure.

For example, when one scheduling request is transmitted after the NTN RTD offset after being transmitted on the PUCCH, the UE may monitor the PDCCH. When one scheduling request is transmitted on the PUCCH, the UE starts an offset timer. When the offset timer expires (or after the offset elapses), the UE can monitor the PDCCH. The offset timer is a timer distinct from the sr-ProhibitTimer and can be indicated by the base station. The offset timer can be stopped / cancelled / released when receiving an uplink grant. Or, the offset timer can be stopped / cancelled / cancelled when the uplink grant can accommodate all pending data available for transmission.

For another example, offset information for considering a large propagation delay of a non-terrestrial network may be configured in the terminal. And the offset information can be added to the sr-ProhibitTimer value or the offset information can be used as the sr-ProhibitTimer value. This prevents the SR from being continuously transmitted during the round trip delay. For example, when a terminal capable of non-terrestrial network communication receives NTN RTD offset information (or information for calculating it), the sr-ProhibitTimer is operated up to the value set in sr-ProhibitTimer plus the NTN RTD offset. You can. Alternatively, when a terminal capable of non-terrestrial network communication receives NTN RTD offset information (or information for indicating it), the value set in sr-ProhibitTimer is ignored and the sr-ProhibitTimer can be operated using the NTN RTD offset. have. Accordingly, the sr-ProhibitTimer for a non-terrestrial network-capable terminal may be configured to have a value greater than the NTN RTD offset. Alternatively, the sr-ProhibitTimer for a non-terrestrial network-capable terminal may be configured with a value in a range greater than the NTN RTD offset.

The offset information or the offset timer described in the above-described embodiments may be used as common information or a common timer, or may be used as individual timers in each case.

As described above, according to the present disclosure, it is possible to effectively perform the NR MAC procedure in a propagation delay environment of a non-terrestrial network.

Hereinafter, a configuration of a terminal and a network node capable of performing part or all of the operation of each of the above-described embodiments will be described once again with reference to the drawings.

18 is a diagram for explaining a terminal configuration according to an embodiment.

Referring to FIG. 18, a terminal 1800 performing communication using a non-terrestrial network includes system information and non-terrestrial network cells including reference round trip delay offset information of a non-terrestrial network cell. Using a receiving unit 1830 for receiving the configuration information necessary to perform communication and a control unit 1810 for performing a random access procedure in the non-terrestrial network cell, and controls the discontinuous reception (DRX) operation based on the configuration information It can contain.

For example, the reference round trip delay offset information may be determined based on a signal transmission time between a terminal and a network node. For example, the reference round trip delay offset information may be determined based on a time difference in which a signal transmitted by a terminal or a network node is received at a network node or terminal. As another example, the reference round trip delay offset information may be determined based on a time difference when a response signal to a signal transmitted by the terminal is received by the terminal. The reference round trip delay offset information may be included in the system information, either explicitly or implicitly.

Meanwhile, after receiving the system information, the controller 1810 may perform a random access procedure to access a network node using a non-terrestrial network.

For example, the terminal 1800 may further include a transmitter 1820 that transmits a message 3 (MSG3) in the case of a contention-based random access procedure. After the message 3 is transmitted, the controller 1810 may start a timer for resolving the contention when the time according to the reference round trip delay offset information elapses, and stop the timer when the contention resolving is completed. That is, when time equal to the reference round trip delay offset has elapsed after the transmission of the message 3, the controller 1810 monitors whether the message 4 is received. The controller 1810 starts a timer for resolving the contention and starts the timer for resolving the contention when the time equal to the reference round trip delay offset has elapsed after the message is transmitted to determine whether the contention is resolved. To complete.

As another example, the transmitter 1820 may transmit a message A (MSG A) in the case of a two-step random access procedure. The controller 1810 may start a response timer when the time according to the reference round trip delay offset information elapses after the message A is transmitted, and stop the response timer when the message B, which is a response message to the message A, is received. That is, when performing a two-step random access procedure consisting of sending a message A and receiving a message B, the transmitter 1820 transmits the message A and when the time equal to the reference round trip delay offset has elapsed, the controller 1810 responds with a response timer. Start to monitor whether message B is received. Thereafter, when the message B is normally received, the controller 1810 ends the response timer and completes the random access procedure.

Meanwhile, the configuration information may include a discontinuous reception HARQ RTT (drx HARQ Round Trip Time) timer or an SR (Scheduling Request) prohibit timer. Here, the discontinuous received HARQ RTT (drx HARQ Round Trip Time) timer or SR (Scheduling Request) prohibit timer may be set to a value greater than the reference round trip delay offset.

In addition, the controller 1810 may perform a DRX operation using a timer included in the configuration information.

As an example, the controller 1810 performs a DRX operation based on a HARQ RTT (drx HARQ Round Trip Time) timer. Also, the reception unit 1830 may receive indication information instructing to deactivate the HARQ feedback operation (HARQ processor). The controller 1810 may disable the discontinuous reception HARQ drx HARQ Round Trip Time (RTT) timer if a disable instruction for the HARQ feedback operation is received.

As another example, the controller 1810 may perform a scheduling request operation based on an SR (Scheduling Request) prohibit timer.

In addition to this, the controller 1810 controls the overall operation of the terminal 1800 according to performing the MAC procedure considering the round trip delay offset in the non-ground network required to perform the above-described embodiment.

The transmitting unit 1820 and the receiving unit 1830 are used to transmit and receive signals, messages, and data necessary to perform the above-described embodiments with a network node.

19 is a diagram illustrating a network node configuration according to an embodiment.

Referring to FIG. 19, a network node 1900 performing communication with a terminal using a non-terrestrial network includes system information and non-grounding including reference round trip delay offset information of a non-grounding network cell. It may include a transmitting unit for transmitting the configuration information necessary for performing communication using a network cell 1920 and a control unit 1910 for performing a random access procedure with the terminal in the non-ground network cell.

 For example, the reference round trip delay offset information may be determined based on a signal transmission time between a terminal and a network node. For example, the reference round trip delay offset information may be determined based on a time difference in which a signal transmitted by a terminal or a network node is received at a network node or terminal. As another example, the reference round trip delay offset information may be determined based on a time difference when a response signal to a signal transmitted by the terminal is received by the terminal. Also, the reference round trip delay offset information may be included in the system information in an explicit or implicit form.

Meanwhile, the control unit 1910 may perform a random access procedure with a terminal attempting to access the network node 1900 using a non-terrestrial network.

For example, in the case of a contention-based random access procedure, the receiver 1930 receives the message 3 (MSG3) from the terminal. After the message 3 is transmitted, when the time according to the reference round trip delay offset information elapses, the terminal starts a timer for resolving contention. The transmitter 1920 transmits a message 4 including response information to the message 3 to the terminal. When the message 4 is received, the terminal stops the timer for contention cancellation and ends the random access procedure. That is, when the time equal to the reference round trip delay offset has elapsed after the transmission of the message 3, the terminal monitors the reception of the message 4.

As another example, in the case of a two-step random access procedure, the reception unit 1930 receives the message A (MSG A). After the message A is transmitted, when the time according to the reference round trip delay offset information elapses, the terminal starts a response timer. The transmitter 1920 transmits the message B, which is a response message to the message A, to the terminal. When the terminal receives the message B, the response timer is stopped. That is, when performing a two-step random access procedure consisting of message A transmission and message B reception, the terminal transmits message A and starts a response timer to determine whether to receive message B when the time equal to the reference round trip delay offset has elapsed. Monitor. Then, when the message B is normally received, the terminal ends the response timer and completes the random access procedure.

Meanwhile, the configuration information may include a discontinuous reception HARQ RTT (drx HARQ Round Trip Time) timer or an SR (Scheduling Request) prohibit timer. Here, the discontinuous received HARQ RTT (drx HARQ Round Trip Time) timer or SR (Scheduling Request) prohibit timer may be set to a value greater than the reference round trip delay offset.

Also, the transmitter 1920 may transmit the indication information for disabling (disable) the HARQ feedback operation of the terminal to the terminal. When the indication information is received, the terminal may disable (disable) the discontinuous reception HARQ RTT (drx HARQ Round Trip Time) timer. As an example, the terminal performs a DRX operation based on a HARQ RTT (drx HARQ Round Trip Time) timer. That is, when the network node 1900 instructs the deactivation for the HARQ feedback operation, the terminal disables the discontinuous reception HARQ drx HARQ Round Trip Time (RTT) timer and does not perform the HARQ feedback operation. As another example, the terminal may perform a scheduling request operation based on an SR (Scheduling Request) prohibit timer.

In addition, the control unit 1910 controls the operation of the overall network node 1900 according to controlling the MAC procedure of the terminal in consideration of the round trip delay offset in the non-ground network required to perform the above-described embodiment.

The transmitting unit 1920 and the receiving unit 1930 are used to transmit and receive signals, messages, and data necessary to perform the above-described embodiments.

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

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

For implementation by hardware, the method according to the embodiments includes one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs), FPGAs (Field Programmable Gate Arrays), a processor, a controller, a microcontroller, or a microprocessor.

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

In addition, the terms “system”, “processor”, “controller”, “component”, “module”, “interface”, “model”, or “unit” described above generally refer to computer-related entity hardware, hardware and software. It can mean a combination of, software or running software. For example, the components described above may be, but are not limited to, processes, processors, controllers, control processors, entities, threads of execution, programs and / or computers driven by a processor. For example, both an application running on a controller or processor and a controller or processor can be components. One or more components can be in a process and / or thread of execution, and the components can be located on one device (eg, a system, computing device, etc.) or distributed across two or more devices.

The above description is merely illustrative of the technical idea of the present disclosure, and those skilled in the art to which the present disclosure pertains may make various modifications and variations without departing from the essential characteristics of the technical idea. In addition, the present embodiments are not intended to limit the technical spirit of the present disclosure, but to explain the scope of the technical spirit of the embodiments. The scope of protection of the present disclosure should be interpreted by the claims below, and all technical spirits within the scope equivalent thereto should be interpreted as being included in the scope of the present disclosure.

Claims (20)

In the method for the terminal to perform communication using a non-terrestrial network (Non-Terrestrial Network),
Receiving system information including reference round trip delay offset information of a non-ground network cell;
Performing a random access procedure in the non-terrestrial network cell;
Receiving configuration information necessary to perform communication using the non-terrestrial network cell; And
And controlling a discontinuous reception (DRX) operation based on the configuration information. According to claim 1,
The step of performing the random access procedure,
In case of a contention-based random access procedure, transmitting message 3 (MSG3);
After transmitting the message 3, when a time according to the reference round trip delay offset information elapses, starting a timer for resolving contention; And
And when the contention resolution is completed, stopping the timer. According to claim 1,
The step of performing the random access procedure,
In the case of a two-step random access procedure, transmitting a message A (MSG A);
Starting the response timer when the time according to the reference round trip delay offset information has elapsed after the message A is transmitted; And
And when the message B, which is a response message to the message A, is received, stopping the response timer. According to claim 1,
The configuration information,
Non-contiguous receiving HARQ RTT (drx HARQ Round Trip Time) timer or includes a SR (Scheduling Request) prohibit timer,
The discontinuous reception HARQ RTT (drx HARQ Round Trip Time) timer or SR (Scheduling Request) prohibit timer is set to a value greater than the reference round trip delay offset. According to claim 1,
The step of controlling the discontinuous reception (DRX) operation,
When a disable instruction for HARQ feedback operation is received, a method of disabling a discontinuous reception HARQ drx HARQ Round Trip Time (RTT) timer. In a method for a network node to communicate with a terminal using a non-terrestrial network,
Transmitting system information including reference round trip delay offset information of the non-ground network cell;
Performing a random access procedure with the terminal in the non-terrestrial network cell; And
And transmitting configuration information necessary to perform communication using the non-terrestrial network cell. The method of claim 6,
The step of performing the random access procedure,
In the case of the contention-based random access procedure, message 3 (MSG3) is received from the terminal,
The terminal,
After the message 3 is transmitted, when a time according to the reference round trip delay offset information has elapsed, a timer for resolving contention is started,
When the contention resolution is completed, the method of stopping the timer. The method of claim 6,
The step of performing the random access procedure,
In the case of a 2-step random access procedure, message A (MSG A) is received from the terminal,
The terminal,
A method of starting a response timer when a time according to the reference round trip delay offset information elapses after the message A is transmitted. The method of claim 6,
The configuration information,
Non-contiguous receiving HARQ RTT (drx HARQ Round Trip Time) timer or includes a SR (Scheduling Request) prohibit timer,
The discontinuous reception HARQ RTT (drx HARQ Round Trip Time) timer or SR (Scheduling Request) prohibit timer is set to a value greater than the reference round trip delay offset. The method of claim 6,
Further comprising the step of transmitting the indication information for disabling (Disable) the HARQ feedback operation of the terminal,
When the indication information is received, the terminal disables the discontinuous reception HARQ RTT (drx HARQ Round Trip Time) timer. In the terminal for performing communication using a non-terrestrial network (Non-Terrestrial Network),
A receiver configured to receive system information including reference round trip delay offset information of a non-ground network cell and configuration information necessary to perform communication using the non-ground network cell; And
A terminal including a control unit that performs a random access procedure in the non-terrestrial network cell and controls discontinuous reception (DRX) operation based on the configuration information. The method of claim 11,
In the case of the contention-based random access procedure, a transmission unit for transmitting the message 3 (MSG3) is further included.
The control unit,
When the time according to the reference round trip delay offset information has elapsed after the message 3 is transmitted, a timer for resolving contention is started,
When the contention resolution is completed, the terminal stops the timer. The method of claim 11,
In the case of the 2-step random access procedure, further comprising a transmitter for transmitting message A (MSG A),
The control unit,
When the time according to the reference round trip delay offset information elapses after the message A is transmitted, a response timer is started,
When the message B, which is a response message to the message A, is received, the terminal stops the response timer. The method of claim 11,
The configuration information,
Non-contiguous receiving HARQ RTT (drx HARQ Round Trip Time) timer or includes a SR (Scheduling Request) prohibit timer,
The non-contiguous receiving HARQ RTT (drx HARQ Round Trip Time) timer or SR (Scheduling Request) prohibit timer is set to a value greater than the reference round trip delay offset. The method of claim 11,
The control unit,
When the disable (Disable) indication for the HARQ feedback operation is received, the terminal characterized in that the discontinuous reception HARQ RTT (drx HARQ Round Trip Time) timer is disabled. In a network node that performs communication with a terminal using a non-terrestrial network,
A transmitter for transmitting system information including reference round trip delay offset information of a non-ground network cell and configuration information necessary for performing communication using the non-ground network cell; And
A network node including a control unit performing a random access procedure with the terminal in the non-ground network cell. The method of claim 16,
In the case of the contention-based random access procedure, further comprising a receiving unit for receiving a message 3 (MSG3) from the terminal,
The terminal,
After the message 3 is transmitted, when a time according to the reference round trip delay offset information has elapsed, a timer for resolving contention is started,
When the contention resolution is completed, the network node that stops the timer. The method of claim 16,
In the case of the 2-step random access procedure, further comprising a receiving unit for receiving the message A (MSG A) from the terminal,
The terminal,
After transmitting the message A, when the time according to the reference round trip delay offset information elapses, a network node that starts a response timer. The method of claim 16,
The configuration information,
Non-contiguous receiving HARQ RTT (drx HARQ Round Trip Time) timer or includes a SR (Scheduling Request) prohibit timer,
The discontinuous reception HARQ RTT (drx HARQ Round Trip Time) timer or SR (Scheduling Request) prohibit timer is set to a value greater than the reference round trip delay offset network node. The method of claim 16,
The transmitting unit,
Transmitting the indication information to disable (Disable) the HARQ feedback operation of the terminal,
When the indication information is received, the terminal disables (disable) the discontinuous reception HARQ RTT (drx HARQ Round Trip Time) timer.

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