Method and apparatus for transmitting and receiving data and control signals from satellite communication terminals in a wireless communication system.

Abstract

The present disclosure relates to a communication technique and system for converging a 5G communication system with IoT technology to support a higher data transmission rate after the 4G system. The present disclosure can be applied to intelligent services (e.g., smart homes, smart buildings, smart cities, smart cars or connected cars, healthcare, digital education, retail, security and safety related services) based on 5G communication technology and IoT related technology. The present invention discloses a method and apparatus for a terminal to perform satellite communication.

Description

Technical Field

[0001] The present invention relates to a communication system, and provides a method and an apparatus for operating in such a manner that, in the case of a terminal capable of supporting both terrestrial network communication and satellite communication, the situation in which the terminal transmits and receives signals varies depending on terrestrial network communication or satellite communication.

Background Art

[0002] Efforts are being made to develop improved 5G or pre-5G communication systems to meet the increasing demand for wireless data traffic since the commercialization of 4G communication systems. For this reason, 5G or pre-5G communication systems are also called Beyond 4G Network communication systems or Post LTE systems. To achieve high data transmission rates, 5G communication systems are being considered for implementation in ultra-high frequency (mmWave) bands (e.g., 60 GHz bands). To mitigate path loss and increase transmission distance in ultra-high frequency bands, beamforming, massive MIMO (Multiple-Input Multiple-Output), FD-MIMO (Full Dimensional MIMO), array antennas, analog beamforming, and large-scale antenna technologies are being discussed for 5G communication systems. Furthermore, to improve the system's network, 5G communication systems are undergoing technological development, including advanced small cells, cloud radio access networks (cloud RAN), ultra-dense networks, D2D (device-to-device) communication, wireless backhaul, moving networks, cooperative communication, CoMP (Coordinated Multi-Points), and interference cancellation.In addition, 5G systems have seen the development of advanced coding modulation (ACM) methods such as FQAM (Hybrid FSK and QAM Modulation) and SWSC (Sliding Window Superposition Coding), as well as advanced connectivity technologies such as FBMC (Filter Bank Multi Carrier), NOMA (non-orthogonal multiple access), and SCMA (sparse code multiple access).

[0003] Meanwhile, the internet is evolving from a human-centered network where humans generate and consume information to an IoT (Internet of Things) network where information is exchanged and processed between distributed components such as objects. IoE (Internet of Everything) technology, which combines IoT technology with big data processing technologies such as cloud servers, is also emerging. Realizing IoT requires technological elements such as sensing technology, wired and wireless communication and network infrastructure, service interface technology, and security technology. In recent years, technologies such as sensor networks, M2M (Machine to Machine), and MTC (Machine Type Communication) for connecting things have been researched. An IoT environment can provide intelligent IT (Internet Technology) services that collect and analyze data generated between connected objects, creating new value in human life. IoT can be applied to fields such as smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, healthcare, smart home appliances, and advanced medical services through convergence and integration with existing IT (information technology) technologies and various industries.

[0004] As a result, various attempts are being made to apply 5G communication systems to IoT networks. For example, 5G communication technologies such as sensor networks, M2M (Machine to Machine), and MTC (Machine Type Communication) can be realized through techniques such as beamforming, MIMO, and array antennas. The application of cloud radio access networks (cloud RAN) as a big data processing technology can also be seen as an example of the convergence of 5G and IoT technologies.

[0005] On the other hand, the dramatic decrease in satellite launch costs in the late 2010s and early 2020s has led to an increase in companies seeking to provide communication services via satellite. As a result, satellite networks have emerged as a next-generation network system that complements existing terrestrial networks. While this may not provide the same user experience as terrestrial networks, it has the advantage of enabling communication services in areas where terrestrial network construction is difficult or in disaster situations. As mentioned earlier, the recent sharp decline in satellite launch costs has also ensured its economic viability. Furthermore, numerous companies and 3GPP standards organizations are also promoting direct communication between smartphones and satellites. [Overview of the project] [Problems that the invention aims to solve]

[0006] This invention proposes a method and apparatus for efficiently providing satellite network communication to terminals. [Means for solving the problem]

[0007] According to one embodiment of the present disclosure for solving the aforementioned problems, a method performed by a terminal of a communication system includes the steps of: determining whether the terminal performs terrestrial network communication or satellite network communication; determining an antenna to be used for transmission and reception based on the determination; and performing communication using the antenna, wherein, if it is determined that satellite network communication will be performed, an antenna included in the terminal that is close to the position of the satellite related to the satellite network communication will be used for communication.

[0008] Furthermore, the terminal of the communication system includes a transmitting and receiving unit and a control unit that determines whether the terminal performs terrestrial network communication or satellite network communication, determines the antenna to be used for transmitting and receiving based on the determination, and controls the system to perform communication using the antenna, wherein, when it is determined that satellite network communication is to be performed, an antenna included in the terminal that is close to the position of the satellite related to the satellite network communication is used for communication. [Effects of the Invention]

[0009] As described above, by utilizing the present invention, a terminal can distinguish between terrestrial network communications and satellite communications, thereby enabling efficient signal transmission and reception. [Brief explanation of the drawing]

[0010] [Figure 1] This diagram shows the basic structure of the time-frequency domain, which is the radio resource area through which the data or control channel is transmitted via downlink or uplink in an NR system. [Figure 2] This diagram shows the control region where the downlink control channel is transmitted in a 5G wireless communication system. [Figure 3] This diagram shows an example of how eMBB, URLLC, and mMTC data are allocated to the overall system frequency band. [Figure 4] This diagram shows an example of how eMBB, URLLC, and mMTC data are allocated to different system frequency bands. [Figure 5]This diagram illustrates an example of the process by which a single transport block is divided into multiple code blocks and CRCs are added to each block. [Figure 6] This diagram shows the frequency and time domain mapping of the synchronization signal (SS) and physical broadcast channel (PBCH) of the NR system. [Figure 7] This diagram shows symbols that indicate how SS / PBCH blocks can be transmitted based on subcarrier intervals. [Figure 8] This diagram shows the processing time of a terminal due to timing advance when a terminal receives a first signal and transmits a second signal in response to it in a 5G or NR system according to one disclosed embodiment. [Figure 9] This diagram illustrates an example of scheduling and transmitting data (e.g., TB) using slots, receiving HARQ-ACK feedback for that data, and retransmitting it based on the feedback. [Figure 10] This is a diagram illustrating an example of a communication system utilizing satellites. [Figure 11] This diagram shows the orbital period of a communications satellite based on its altitude or height. [Figure 12] This is a diagram illustrating the concept of direct satellite-terminal communication. [Figure 13] This diagram illustrates a scenario for utilizing direct satellite-terminal communication. [Figure 14] This diagram shows an example of calculating the expected data transmission rate (throughput) via uplink when a LEO satellite at an altitude of 1200 km communicates directly with a ground terminal. [Figure 15] This diagram shows an example of calculating the expected data transmission rate (throughput) via uplink when a GEO satellite at an altitude of 35,786 km communicates directly with a ground terminal. [Figure 16] This diagram shows the path loss values ​​based on the path loss model between the terminal and the satellite, and the path loss based on the path loss model between the terminal and the terrestrial network base station. [Figure 17]This diagram shows a formula and results for calculating the amount of Doppler shift that a signal transmitted from a satellite experiences when received by a ground user, based on the satellite's altitude and position, and the position of the ground terminal user. [Figure 18] This diagram shows the satellite's velocity calculated based on its altitude. [Figure 19] This diagram shows the Doppler shift experienced by different terminals within a single beam transmitted from a satellite to the ground. [Figure 20] This diagram shows the difference in Doppler shift occurring within one beam, depending on the satellite's position determined by the altitude angle. [Figure 21] This diagram shows the delay time from the terminal to the satellite, and the round-trip delay time between the terminal, satellite, and base station, based on the satellite's position determined by its altitude. [Figure 22] This diagram shows the maximum difference in round-trip delay time within a single beam, which varies depending on the user's position. [Figure 23] This diagram illustrates an example of a case where a single terminal can perform both terrestrial network communication and satellite-to-terminal direct communication functions. [Figure 24] This is a diagram showing the structure and location of the terminal's transmitting and receiving antennas. [Figure 25] This diagram illustrates an example of how a user can arbitrarily adjust the orientation of their device. [Figure 26] This diagram shows how a terminal determines the antenna used for communication. [Figure 27] This is a block diagram showing the internal structure of a terminal according to an embodiment of the present invention. [Figure 28] This is a block diagram showing the internal structure of a base station according to an embodiment of the present invention. [Figure 29] Block diagram showing the internal structure of a satellite according to an embodiment of the present invention. [Modes for carrying out the invention]

[0011] In the new 5G communication technology, NR (New Radio Access Technology), diverse services can be freely multiplexed using time and frequency resources. This allows for the dynamic or free allocation of waveform / numerology and reference signals according to the needs of the service. To provide the best possible service to terminals in wireless communication, optimized data transmission through measurement of channel quality and interference is crucial, making accurate channel condition measurement essential. However, unlike 4G communication, where channel and interference characteristics do not change significantly depending on frequency resources, 5G channels exhibit significant variations in channel and interference characteristics depending on the service. Therefore, support for a subset of the FRG (Frequency Resource Group) dimension is necessary to measure these separately. On the other hand, the types of services supported in NR systems can be categorized as eMBB (Enhanced Mobile Broadband), mMTC (Massive Machine Type Communications), and URLLC (Ultra-Reliable and Low-Latency Communications). eMBB is seen as a service aiming for high-speed transmission of high-capacity data, mMTC as minimizing terminal power consumption and connecting a large number of terminals, and URLLC as a service aiming for high reliability and low latency. Different requirements may apply depending on the type of service applied to the terminal.

[0012] In this way, multiple services can be provided to a user in a communication system, and in order to provide such multiple services to a user, there is a need for a method and device that can provide each service within the same time interval according to its characteristics.

[0013] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.

[0014] In describing the embodiments, explanations of technical content that is well known in the art to which this disclosure belongs and is not directly related to this disclosure will be omitted. This is to clarify and more clearly communicate the gist of this disclosure by omitting unnecessary explanations.

[0015] For similar reasons, some components in the attached drawings are exaggerated, omitted, or only schematically represented. Furthermore, the sizes of each component do not fully reflect their actual dimensions. The same reference number is used for identical or corresponding components in each drawing.

[0016] The advantages and features of this disclosure, and how they are achieved, will become clear from the examples described below in detail with the accompanying drawings. However, this disclosure is not limited to the examples disclosed below and can be embodied in a variety of different forms, except that these examples are provided to complete the disclosure and to fully inform those ordinary skill in the art to which the disclosure belongs of its scope, and the disclosure is defined only by the claims. Throughout the specification, the same reference numerals refer to the same components.

[0017] At this point, it can be understood that the combination of each block of the processing flowchart and the flowchart diagram can be performed by computer program instructions. Since these computer program instructions can be implemented on the processor of a general-purpose computer, a special-purpose computer, or other programmable data processing equipment, the instructions, delivered via the processor of the computer or other programmable data processing equipment, will generate means for performing the functions described in the flowchart blocks. Since these computer program instructions can also be stored in computer-available or computer-readable memory that can direct the computer or other programmable data processing equipment to embody the functions in a particular manner, the instructions stored in such computer-available or computer-readable memory can also produce manufactured items that contain instruction means for performing the functions described in the flowchart blocks. Since computer program instructions can also be implemented on a computer or other programmable data processing equipment, the instructions, which perform a series of operational steps on the computer or other programmable data processing equipment and generate processes to be executed on the computer, can also provide steps for performing the functions described in the flowchart blocks.

[0018] Furthermore, each block may represent a module, segment, or portion of code containing one or more executable instructions for performing a specified logical function. It should also be noted that in some alternative execution examples, the functions mentioned in a block may occur out of order. For example, two adjacent blocks may actually be performed substantially simultaneously, or they may sometimes be performed in reverse order by the functions in question.

[0019] In this embodiment, the term '~part' refers to software or hardware components such as FPGAs or ASICs, and the role that '~part' plays is not limited to software or hardware. '~part' can also be configured to reside in an addressable storage medium, or to regenerate one or more processors. Therefore, as an example, '~part' includes components such as software components, object-oriented software components, class components, and task components, as well as processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functions provided by the components and '~part' can be combined with a smaller number of components and '~part' or further separated with additional components and '~part'. Furthermore, components and '~part' can also be embodied to regenerate one or more CPUs within a device or security multimedia card. In this embodiment, '~part' may also include one or more processors.

[0020] Wireless communication systems have evolved from providing early voice-centric services to broadband wireless communication systems that offer high-speed, high-quality packet data services, such as 3GPP's HSPA (High Speed ​​Packet Access), LTE (Long Term Evolution or E-UTRA (Evolved Universal Terrestrial Radio Access)), LTE-Advanced (LTE-A), LTE-Pro, 3GPP2's HRPD (High Rate Packet Data), UMB (Ultra Mobile Broadband), and IEEE's 802.16e. Furthermore, 5G or NR (new radio) communication standards have been developed for 5th generation wireless communication systems.

[0021] In the NR system, a typical example of the aforementioned broadband wireless communication system, the OFDM (orthogonal frequency division multiplexing) method is employed for both the downlink (DL) and uplink (UL). In this invention, the downlink (DL) refers to the wireless transmission path of signals transmitted from the base station to the terminal, and the uplink (UL) refers to the wireless transmission path of signals transmitted from the terminal to the base station. More specifically, the CP-OFDM (cyclic-prefix OFDM) method is employed for the downlink, while both the CP-OFDM and the DFT-S-OFDM (discrete Fourier transform spreading OFDM) method are employed for the uplink. The uplink refers to the wireless link on which a terminal (user equipment, UE or mobile station, MS) transmits data or control signals to a base station (gNode B or base station, BS), and the downlink refers to the wireless link on which a base station transmits data or control signals at the terminal. The aforementioned multiplexing scheme typically divides each user's data or control information by allocating and manipulating time-frequency resources for transmitting data or control information for each user in such a way that they do not overlap, i.e., orthogonality is maintained.

[0022] The NR system employs the HARQ (hybrid automatic repeat request) method, which retransmits data at the physical layer if a decoding failure occurs during the initial transmission. In the HARQ method, if the receiver cannot accurately decode the data, the receiver sends information to the transmitter indicating the decoding failure (negative acknowledgement, NACK), allowing the transmitter to retransmit the data at the physical layer. The receiver then combines the retransmitted data with the previously decoded data to improve data reception performance. Furthermore, if the receiver successfully decodes the data, it sends information to the transmitter indicating the decoding success (acknowledgement, ACK), and the transmitter transmits new data.

[0023] Figure 1 is a diagram showing the basic structure of the time-frequency domain, which is the radio resource area in an NR system where the data or control channel is transmitted via downlink or uplink.

[0024] In Figure 1, the horizontal axis represents the time domain, and the vertical axis represents the frequency domain. The smallest transmission unit in the time domain is N as an OFDM symbol. symb 102 OFDM symbols come together to form one slot 106. The length of a subframe is defined as 1.0 ms, and a radio frame 114 is defined as 10 ms. The smallest transmission unit in the frequency domain is the subcarrier, and the total bandwidth of the overall system transmission bandwidth is N. BW It consists of 104 subcarriers. One frame can be defined as 10ms. One subframe can be defined as 1ms, and therefore one frame can consist of a total of 10 subframes. One slot can be defined as 14 OFDM symbols (i.e., the number of symbols per slot(

number

number

number

number

[0025] [Table 1]

[0026] Prior to an RRC (radio resource control) connection, the terminal can have its initial bandwidth part (initial BWP) configured by the base station via the MIB (master information block). More specifically, during the initial connection phase, the terminal can receive configuration information for the control resource set (CORESET) and search space via the MIB, which can transmit a PDCCH (physical downlink control channel) for receiving the system information necessary for the initial connection (which can correspond to remaining system information, RMSI, or system information block 1, SIB1). The MIB, the configured control resource set, and the search space can each be considered as having identifier (ID) 0. The base station can notify the terminal of configuration information such as frequency allocation information, time allocation information, and numerology for control resource set #0 via the MIB. The base station can also notify the terminal of configuration information for the monitoring period and occasion for control resource set #0, i.e., configuration information for search space #0, via the MIB. The terminal can consider the control area #0 and the frequency area set from the MIB as the initial bandwidth portion for initial connection. In this case, the identifier (ID) of the initial bandwidth portion can be considered as 0.

[0027] The MIB can contain the following information:

[0028] -- ASN1START

[0029] -- TAG-MIB-START

[0030] MIB::=SEQUENCE{

[0031] systemFrameNumber BIT STRING(SIZE(6)),

[0032] subCarrierSpacingCommon ENUMERATED{scs15or60,scs30or120},

[0033] ssb-SubcarrierOffset INTEGER(0..15),

[0034] dmrs-TypeA-Position ENUMERATED{pos2,pos3},

[0035] pdcch-ConfigSIB1 PDCCH-ConfigSIB1,

[0036] cellBarred ENUMERATED{barred,notBarred},

[0037] intraFreqReselection ENUMERATED {allowed,notAllowed},

[0038] spare BIT STRING(SIZE(1))

[0039] }

[0040] -- TAG-MIB-STOP

[0041] -- ASN1STOP

[0042] MIB field descriptions

[0043] - cellBarred

[0044] Value barred means that the cell is barred,as defined in TS 38.304

[20] .

[0045] - dmrs-TypeA-Position

[0046] Position of(first)DM-RS for downlink(see TS 38.211

[16] ,clause 7.4.1.1.2)and uplink(see TS 38.211

[16] ,clause 6.4.1.1.3).

[0047] - intraFreqReselection

[0048] Controls cell selection / reselection to intra-frequency cells when the highest ranked cell is barred,or treated as barred by the UE,as specified in TS 38.304

[20] .

[0049] - pdcch-ConfigSIB1

[0050] Determines a common ControlResourceSet(CORESET),a common search space and necessary PDCCH parameters. If the field ssb-SubcarrierOffset indicates that SIB1 is absent,the field pdcch-ConfigSIB1 indicates the frequency positions where the UE may find SS / PBCH block with SIB1 or the frequency range where the network does not provide SS / PBCH block with SIB1(see TS 38.213

[13] ,clause 13).

[0051] - ssb-SubcarrierOffset

[0052] Corresponds to kSSB(see TS 38.213

[13] ),which is the frequency domain offset between SSB and the overall resource block grid in number of subcarriers. (See TS 38.211

[16] ,clause 7.4.3.1).

[0053] The value range of this field may be extended by an additional most significant bit encoded within PBCH as specified in TS 38.213

[13] .

[0054] This field may indicate that this cell does not provide SIB1 and that there is hence no CORESET#0 configured in MIB(see TS 38.213

[13] ,clause 13). In this case,the field pdcch-ConfigSIB1 may indicate the frequency positions where the UE may(not)find a SS / PBCH with a control resource set and search space for SIB1(see TS 38.213

[13] ,clause 13).

[0055] - subCarrierSpacingCommon

[0056] Subcarrier spacing for SIB1,Msg.2 / 4 for initial access,paging and broadcast SI-messages. If the UE acquires this MIB on an FR1 carrier frequency,the value scs15or60 corresponds to 15 kHz and the value scs30or120 corresponds to 30 kHz. If the UE acquires this MIB on an FR2 carrier frequency,the value scs15or60 corresponds to 60 kHz and the value scs30or120 corresponds to 120 kHz.

[0057] - systemFrameNumber

[0058] The 6 most significant bits(MSB)of the 10-bit System Frame Number(SFN). The 4 LSB of the SFN are conveyed in the PBCH transport block as part of channel coding(i. e. outside the MIB encoding),as defined in clause 7.1 in TS 38.212

[17] .

[0059] In the method of configuring the bandwidth portion, a terminal before RRC connection (connected) can receive configuration information for the initial bandwidth portion via the MIB during the initial connection phase. More specifically, the terminal can configure a control area for a downlink control channel from the PBCH (physical broadcast channel) MIB, from which DCI (downlink control information) that schedules SIBs can be transmitted. At this time, the bandwidth of the control area configured in the MIB can be considered the initial bandwidth portion, and the terminal can receive the PDSCH (physical downlink shared channel) from which SIBs are transmitted via the configured initial bandwidth portion. In addition to receiving SIBs, the initial bandwidth portion can also be used for other system information (OSI), paging, and random access.

[0060] If one or more bandwidth parts are configured on a terminal, the base station can use the bandwidth part indicator field in the DCI to instruct the terminal to make changes to the bandwidth parts.

[0061] In NR systems, in FDD systems where downlink and uplink are operated separately by frequency, the downlink transmit bandwidth and uplink transmit bandwidth can differ from each other. The channel bandwidth indicates the RF bandwidth corresponding to the system transmit bandwidth. Tables 2 and 3 show some of the correspondences between the system transmit bandwidth, subcarrier spacing, and channel bandwidth defined for NR systems in frequency bands below 6 GHz and above 6 GHz, respectively. For example, an NR system with a 30 kHz subcarrier spacing and a 100 MHz channel bandwidth has a transmit bandwidth composed of 273 RBs. Below, N / A indicates a bandwidth-subcarrier combination that is not supported by the NR system.

[0062] [Table 2]

[0063] [Table 3]

[0064] In an NR system, the frequency range can be defined as FR1 and FR2, as shown in Table 4 below.

[0065] [Table 4]

[0066] As mentioned above, the ranges of FR1 and FR2 can be modified and applied differently. For example, the frequency range of FR1 can be changed and applied from 450MHz to 6000MHz.

[0067] Next, we will explain the synchronization signal / physical broadcast channel block (SS) / PBCH (physical broadcast channel block) in 5G.

[0068] An SS / PBCH block can refer to a physical hierarchy channel block composed of PSS (primary SS), SSS (secondary SS), and PBCH. Specifically, it is as follows:

[0069] -PSS: A reference signal for downlink time / frequency synchronization that provides some information about the cell ID.

[0070] -SSS: Serves as the reference for downlink time / frequency synchronization and provides remaining cell ID information that PSS does not provide. Additionally, it can serve as a reference signal for PBCH demodulation.

[0071] -PBCH: Provides essential system information necessary for transmitting and receiving data and control channels of the terminal. Essential system information may include search space-related control information indicating wireless resource mapping information for the control channel, scheduling control information for a separate data channel that transmits system information, etc.

[0072] -SS / PBCH Block: An SS / PBCH block consists of a combination of PSS, SSS, and PBCH. One or more SS / PBCH blocks can be transmitted within a 5ms time, and each transmitted SS / PBCH block can be distinguished by an index.

[0073] The terminal can detect the PSS and SSS during the initial connection phase and decode the PBCH. The terminal can obtain the MIB from the PBCH and configure control area #0 (which may correspond to a control area with a control area index of 0). The terminal can monitor control area #0, assuming that the DMRS (demodulation reference signal) transmitted from the selected SS / PBCH block and control area #0 are quasi-co-located (QCL). The terminal can receive system information from the downlink control information transmitted from control area #0. From the received system information, the terminal can obtain the RACH (random access channel) related configuration information necessary for the initial connection. The terminal can send a PRACH (physical RACH) to the base station, taking into account the selected SS / PBCH index, and the base station, upon receiving the PRACH, can obtain information for the SS / PBCH block index selected by the terminal. Through this process, the base station understands that the terminal has selected one of the SS / PBCH blocks and is monitoring the control area #0 associated with it.

[0074] Next, we will specifically explain downlink control information (DCI) in 5G systems.

[0075] In a 5G system, scheduling information for uplink data (or physical uplink shared channel, PUSCH) or downlink data (or physical downlink shared channel, PDSCH) is transmitted from the base station to the terminal via DCI. The terminal can monitor the PUSCH or PDSCH in both fallback and non-fallback DCI formats. The fallback DCI format can consist of predefined fixed fields between the base station and the terminal, while the non-fallback DCI format can include configurable fields. In addition, various other DCI formats exist, each indicating whether it is a DCI for power control, a DCI for notifying an SFI (slot format indicator), etc.

[0076] DCI messages can be transmitted via the PDCCH, a physical downlink control channel, after channel coding and modulation. A cyclic redundancy check (CRC) is attached to the DCI message payload, and this CRC can be scrambled with a radio network temporary identifier (RNTI) corresponding to the terminal's identity. Different RNTIs may be used depending on the purpose of the DCI message, such as terminal-specific (UE-specific) data transmission, power control commands, or random success responses. That is, the RNTI is not explicitly transmitted but is included in the CRC calculation process. Upon receiving a DCI message transmitted over the PDCCH, the terminal checks the CRC using its assigned RNTI, and if the CRC check is correct, the terminal knows that the message has been transmitted to it. The PDCCH is mapped and transmitted using the control area configured on the terminal.

[0077] For example, a DCI that schedules PDSCH for system information (SI) can be scrambled with SI-RNTI. A DCI that schedules PDSCH for RAR (random access response) messages can be scrambled with RA-RNTI. A DCI that schedules PDSCH for paging messages can be scrambled with P-RNTI. A DCI that notifies SFI (slot format indicator) can be scrambled with SFI-RNTI. DCIs that notify TPC (transmit power control) can be scrambled with TPC-RNTI. DCIs that schedule terminal-specific PDSCH or PUSCH can be scrambled with C-RNTI (Cell RNTI).

[0078] DCI format 0_0 can be used as a fallback DCI for scheduling pushes, in which case the CRC can be scrambled with C-RNTI. DCI format 0_0 with CRC scrambled with C-RNTI can include information such as the following:

[0079] [Table 5]

[0080] DCI format 0_1 ​​can be used in non-fallback DCI for scheduling pushes, in which case the CRC can be scrambled with C-RNTI. DCI format 0_1 ​​with CRC scrambled with C-RNTI can include, for example, the following information:

[0081] [Table 6A]

[0082] [Table 6B]

[0083] [Table 6C]

[0084] DCI format 1_0 can be used as a fallback DCI for scheduling PDSCH, in which case the CRC can be scrambled with C-RNTI. DCI format 1_0 with CRC scrambled with C-RNTI can include the following information, for example:

[0085] [Table 7]

[0086] DCI format 1_1 can be used in non-fallback DCI for scheduling PDSCH, in which case the CRC can be scrambled with C-RNTI. DCI format 1_1 with CRC scrambled with C-RNTI can include, for example, the following information:

[0087] [Table 8A]

[0088] [Table 8B]

[0089] The control information included in the aforementioned DCI format 1_1 is as follows:

[0090] - Carrier indicator: Indicates which carrier the data scheduled by DCI will be transmitted on - 0 or 3 bits

[0091] - Identifier for DCI formats: An indicator that specifies the DCI format and distinguishes whether the DCI is for downlink or uplink. -[1] bits

[0092] -Bandwidth part indicator: Indicates if there is a change in the bandwidth portion - 0, 1, or 2 bits

[0093] -Frequency domain resource assignment: Resource assignment information that instructs frequency domain resource assignment. The resources represented vary depending on whether the resource assignment type is 0 or 1.

[0094] -Time domain resource assignment: Resource assignment information that instructs time domain resource assignment, which can instruct higher-level signaling or the setting of a predetermined PDSCH time domain resource assignment list - 1, 2, 3, or 4 bits

[0095] -VRB-to-PRB mapping: Specifies the mapping relationship between virtual resource blocks (VRBs) and physical resource blocks (PRBs) - 0 or 1 bit

[0096] -PRB bundling size indicator: Indicates the physical resource block bundling size assuming the same precoding is applied -0 or 1 bit

[0097] -Rate matching indicator: Indicates which rate matching group from the higher-level rate matching groups applied to the PDSCH will be applied - 0, 1, or 2 bits

[0098] -ZP CSI-RS trigger: Triggers the zero-power channel state information reference signal -0, 1, or 2 bits

[0099] -Transport block (TB) related configuration information: Specifies the MCS (Modulation and coding scheme), NDI (New data indicator), and RV (Redundancy version) for one or two TBs.

[0100] - Modulation and coding scheme (MCS): Specifies the modulation scheme and coding rate used for data transmission. Specifically, it can specify a coding rate value that can notify TBS and channel coding information, along with information on whether it is QPSK, 16QAM, 64QAM, or 256QAM.

[0101] - New data indicator: Indicates whether it is an initial HARQ transmission or a retransmission.

[0102] -Redundancy version: Specifies a redundancy version of HARQ.

[0103] -HARQ process number: Specifies the HARQ process number to apply to PDSCH - 4 bits

[0104] -Downlink assignment index: This is the index used to generate the dynamic HARQ-ACK codebook when reporting HARQ-ACK to PDSCH - 0, 2, or 4 bits

[0105] -TPC command for scheduled PUCCH: Power control information applied to PUCCH for HARQ-ACK reporting to PDSCH - 2 bits

[0106] -PUCCH resource indicator: Information indicating PUCCH resources for HARQ-ACK reporting to PDSCH - 3 bits

[0107] -PDSCH-to-HARQ_feedback timing indicator: Configuration information for which slot PUCCH is sent for HARQ-ACK reporting to PDSCH - 3 bits

[0108] - Antenna ports: Information indicating the antenna ports of the PDSCH DMRS and DMRS CDM groups that do not transmit PDSCH - 4, 5, or 6 bits

[0109] - Transmission configuration indication: Information indicating beam-related information for the PDSCH - 0 or 3 bits

[0110] -SRS request: Information requesting SRS transmission - 2 bits

[0111] -CBG transmission information: If code block group base retransmission is configured, this information indicates which code block group (CBG) the data corresponding to will be transmitted via the PDSCH - 0, 2, 4, 6, or 8 bits

[0112] -CBG flushing out information: Information indicating whether a code block group previously received by the terminal can be used for HARQ combining - 0 or 1 bit

[0113] -DMRS sequence initialization: Specifies DMRS sequence initialization parameters - 1 bit

[0114] The following describes the method for allocating time-domain resources to data channels in a 5G communication system.

[0115] A base station can configure tables for time-domain resource allocation information for downlink data channels (PDSCH) and uplink data channels (PUSCH) at terminals using higher-level signaling (e.g., RRC signaling). For PDSCH, a table consisting of a maximum of maxNrofDL-Allocations=16 entries can be configured, and for PUSCH, a table consisting of a maximum of maxNrofUL-Allocations=16 entries can be configured. Time-domain resource allocation information may include, for example, PDCCH-to-PDSCH slot timing (corresponding to the time interval in slots between when a PDCCH is received and when the PDSCH scheduled by the received PDCCH is transmitted, denoted as K0) or PDCCH-to-PUSCH slot timing (corresponding to the time interval in slots between when a PDCCH is received and when the PUSCH scheduled by the received PDCCH is transmitted, denoted as K2), information on the position and length of the start symbol in which a PDSCH or PUSCH is scheduled within a slot, and the mapping type of the PDSCH or PUSCH. For example, information like that shown in Tables 9 and 10 below can be sent from the base station to the terminal.

[0116] [Table 9]

[0117] [Table 10]

[0118] The base station can notify the terminal of one of the table entries for the time domain resource allocation information via L1 signaling (e.g., DCI) (for example, it can be indicated in the 'Time Domain Resource Allocation' field within the DCI). Based on the DCI received from the base station, the terminal can obtain the time domain resource allocation information for the PDSCH or PUSCH.

[0119] In the case of data transmission via PDSCH or PUSCH as described above, time domain resource assignment can be communicated by information about the slot to which the PDSCH or PUSCH is transmitted, and by the starting symbol position S in that slot and the number of symbols L to which the PDSCH or PUSCH is mapped. S can be a position relative to the start of the slot, and L can be a number of consecutive symbols. S and L can be determined from the start and length indicator value (SLIV) defined as shown in Equation 1 below.

[0120]

number

[0121] In the NR system, terminals can configure information regarding the SLIV value, PDSCH / PUSCH mapping type, and the slot to which PDSCH / PUSCH is transmitted in a single row via RRC settings (for example, this information can be configured in the form of a table). Subsequently, in the DCI time domain resource allocation, the base station can transmit the SLIV value, PDSCH / PUSCH mapping type, and the information regarding the slot to which PDSCH / PUSCH is transmitted to the terminal by specifying the index value in the configured table.

[0122] In the NR system, two PDSCH mapping types were defined: type A and type B. In PDSCH mapping type A, the first symbol of the DMRS symbols is located in the second or third OFDM symbol of the slot. In PDSCH mapping type B, the first symbol of the DMRS symbols is located in the first OFDM symbol in the time-domain resource allocated by the PUSCH transmission.

[0123] The following section provides a more detailed explanation of the downlink control channel in a 5G communication system, with reference to the diagrams.

[0124] Figure 2 is a diagram illustrating an example of a control region to which a downlink control channel is transmitted in a 5G wireless communication system. Figure 2 shows an example in which the terminal bandwidth portion (UE bandwidth part) 210 is set on the frequency axis and two control regions (control region #1 (201) and control region #2 (202)) are set within one slot 220 on the time axis. Control regions 201 and 202 can be set to specific frequency resources 203 within the total terminal bandwidth portion 210 on the frequency axis. On the time axis, they can be set to one or more OFDM symbols, which can be defined as the control region length (control resource set duration, 204). Referring to the example illustrated in Figure 2, control region #1 (201) is set to a control region length of 2 symbols, and control region #2 (202) is set to a control region length of 1 symbol.

[0125] The control area in the aforementioned 5G system can be configured by the base station to the terminal via higher-level signaling (e.g., system information, MIB, RRC signaling). Configuring a control area to the terminal means providing information such as the control area identifier (Identity), the frequency position of the control area, and the symbol length of the control area. For example, the higher-level signaling may include the information shown in Table 11 below.

[0126] [Table 11]

[0127] In Table 11, the tci-StatesPDCCH (simply named TCI (transmission configuration indication) state) configuration information can include information on one or more SS / PBCH block indices or CSI-RS (channel state information reference signal) indices that have a QCL relationship with the DMRS transmitted in the corresponding control domain.

[0128] Downlink data can be transmitted over a PDSCH, which is a physical channel for transmitting downlink data. The PDSCH can be transmitted from after the control channel transmission section, and scheduling information such as the specific mapping position in the frequency domain and the modulation scheme is determined based on the DCI transmitted via the PDCCH.

[0129] Through the MCS, one of the control information constituting the DCI, the base station notifies the terminal of the modulation scheme applied to the PDSCH to be transmitted and the size of the data to be transmitted (transport block size, TBS). In this embodiment, the MCS may consist of 5 bits or more or fewer bits. The TBS corresponds to the size of the data (transport block, TB) that the base station intends to transmit before channel coding for error correction is applied.

[0130] In this invention, a transport block (TB) may include a MAC (medium access control) header, MAC control elements, one or more MAC SDUs (service data units), and padding bits. Alternatively, a TB may refer to a unit of data delivered from the MAC layer to the physical layer or a MAC PDU (protocol data unit).

[0131] The modulation schemes supported by the NR system are QPSK (quadrature phase shift keying), 16QAM (quadrature amplitude modulation), 64QAM, and 256QAM, with their respective modulation order (Q). m ) corresponds to 2, 4, 6, and 8. That is, in the case of QPSK modulation, 2 bits per symbol can be transmitted; in the case of 16QAM modulation, 4 bits per symbol can be transmitted; in the case of 64QAM modulation, 6 bits per symbol can be transmitted; and in the case of 256QAM modulation, 8 bits per symbol can be transmitted.

[0132] Figures 3 and 4 are diagrams illustrating an example of how eMBB, URLLC, and mMTC data, which are services considered in 5G or NR systems, are allocated to frequency-time resources.

[0133] By referring to Figures 3 and 4, you can see how frequency and time resources are allocated for information transmission in each system.

[0134] Figure 3 is a diagram showing an example of how eMBB, URLLC, and mMTC data are allocated to the overall system frequency band. First, Figure 3 shows a configuration in which data for eMBB, URLLC, and mMTC are allocated to the overall system frequency band 300. If URLLC data 303, 305, and 307 are generated and require transmission while eMBB 301 and mMTC 309 are being allocated and transmitted in a specific frequency band, the portion already allocated to eMBB 301 and mMTC 309 can be left empty or not transmitted, and URLLC data 303, 305, and 307 can be transmitted. In the aforementioned service, it is necessary to reduce the delay time of URLLC, so URLLC data (303, 305, and 307) can be allocated to a portion of the resource 301 to which eMBB is allocated and transmitted. Of course, if URLLC is additionally allocated and transmitted in a resource to which eMBB is allocated, eMBB data may not be transmitted in the overlapping frequency-time resources, and therefore the transmission performance of eMBB data may be reduced. In other words, in the above case, eMBB data transmission failure due to URLLC assignment can occur.

[0135] Figure 4 is a diagram illustrating an example of how the system frequency band can be divided and allocated eMBB, URLLC, and mMTC data. In Figure 4, the overall system frequency band 400 can be divided and used to transmit services and data in subbands 402, 404, and 406. Information regarding the subband configuration can be predetermined, and this information can be transmitted by the base station to the terminal via higher-level signaling. Alternatively, the subbands can be arbitrarily divided by the base station or network node, and services can be provided to the terminal without transmitting separate subband configuration information. In Figure 4, subband 402 is used for eMBB data transmission, subband 404 for URLLC data transmission, and subband 406 for mMTC data transmission.

[0136] The terms "physical channel" and "signal" in NR systems may be used to describe the methods and apparatus proposed in the examples. However, the contents of the present invention can also be applied to wireless communication systems other than NR systems.

[0137] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Furthermore, if it is determined that a specific explanation of a related function or configuration would unnecessarily obscure the gist of the invention, such detailed explanation will be omitted. The terms used later are defined in consideration of the functions of the present invention, and these may change depending on the user's or operator's intent or convention. Therefore, their definitions should be based on the content of this specification as a whole.

[0138] The embodiments of the present invention will be described below using an NR system as an example, but embodiments of the present invention can also be applied to other communication systems with similar technical backgrounds or channel configurations. Furthermore, embodiments of the present invention can be applied to other communication systems with some modifications, without significantly departing from the scope of the invention, as judged by a person with skilled technical knowledge.

[0139] In this invention, the conventional terms "physical channel" and "signal" can be used interchangeably with "data" or "control signal." For example, PDSCH is a physical channel through which data is transmitted, but in this invention, PDSCH can be used as data.

[0140] In this invention, higher-level signaling is a signal transmission method that transmits signals from a base station to a terminal using a physical layer downlink data channel, or from a terminal to a base station using a physical layer uplink data channel, and may also be referred to as RRC signaling or MAC control element (MAC CE).

[0141] FIG. 5 is a drawing showing an example of a process in which a single transmission block is divided into a number of code blocks and CRC is added thereto.

[0142] Referring to FIG. 5, CRC (503) can be added to the last or the frontmost part of a single transmission block (TB, 501) to be transmitted in the uplink or the downlink. CRC 503 can have 16 bits or 25 bits or a fixed number of bits in advance or can have a variable number of bits depending on the channel situation or the like, and can be used to determine whether or not the channel coding is successful. The block obtained by adding CRC 503 to TB 501 can be divided into a number of code blocks (codeblock, CB) 507, 509, 511, 513 (505). Here, the code block can be divided with a predetermined maximum size, and in this case, the last code block 513 may be smaller in size than the other code blocks 507, 509, 511. However, this is only an example, and in other examples, 0, a random value, or 1 is inserted into the last code block 513 so that the lengths of the last code block 513 and the other code blocks 507, 509, 511 are made constant.

[0143] Also, CRCs 517, 519, 521, 523 can be added to the code blocks 507, 509, 511, 513 respectively (515). The CRC can have 16 bits or 24 bits or a fixed number of bits in advance, and can be used to determine whether or not the channel coding is successful.

[0144] TB 501 and a cyclic generator polynomial can be used to generate CRC 503, and the cyclic generator polynomial can be defined in various ways. For example, for a 24-bit CRC, the cyclic generator polynomial gCRC24A(D) = D 24 + D 23 + D 18 + D 17 + D 14 + D 11 + D10 +D 7 +D 6 +D 5 +D 4 +D 3 Assuming +D+1 and L=24, the TB data a0, a1, a2, a3, ... a A-1 In contrast, CRCp0,p1,p2,p3,...p L-1 is a0D A+23 +a1D A+22 +...+a A-1 D 24 +p0D 23 +p1D 22 +...+p 22 D 1 +p 23 The values ​​p0, p1, p2, p3, ... p are the values ​​where the remainder is 0 when divided by gCRC24A(D). L-1 This can be determined. In the example above, we assumed that the CRC length L was 24, but the CRC length L can be determined to be various lengths such as 12, 16, 24, 32, 40, 48, 64, etc.

[0145] After the CRC is added to the TB in this process, the TB+CRC can be divided into N CBs 507, 509, 511, 513. CRCs 517, 519, 521, 523 can be added to each of the divided CBs 507, 509, 511, 513 (515). The CRC added to the CBs may have a different length than the CRC added to the TB, or other cyclic generating polynomials may be used for CRC generation. In addition, the CRC 503 added to the TB and the CRCs 517, 519, 521, 523 added to the code block may be omitted depending on the type of channel code applied to the code block. For example, if an LDPC code is applied to the code block instead of a turbo code, the CRCs 517, 519, 521, 523 inserted for each code block may be omitted.

[0146] However, even when LDPC is applied, CRCs 517, 519, 521, and 523 can still be added to the code block. Similarly, when polar tie codes are used, CRCs can be added or omitted.

[0147] As mentioned earlier in Figure 5, the TB to be transmitted has a maximum code block length determined according to the type of channel coding applied, and the TB and the CRC added to the TB can be divided into code blocks according to the maximum code block length.

[0148] In conventional LTE systems, a CRC for the CB is added to the divided CB, and the CB's data bits and CRC are encoded with the channel code, determining the coded bits, and the number of bits to be rate-matched for each coded bit is determined as agreed upon in advance.

[0149] In the NR system, the size of the TB (TBS) can be calculated through the following steps.

[0150] Stage 1: N' of the number of REs allocated to PDSCH mapping in one of the allocated resources, the PRB. RE Calculate N' RE teeth

number

number

number

number

number

[0151] Stage 2: Number of temporary information bits N info is N RE ·R·Q m It can be calculated using v, where R is the code rate and Q m is the modulation order, and information about this value can be transmitted using the DCI's MCS bitfield and a pre-agreed table. Also, v is the number of layers assigned. If N info If the value is ≤3824, the TBS can be calculated via step 3 below. Otherwise, the TBS can be calculated via step 4.

[0152] Stage 3:

number

[0153] [Table 12]

[0154] Stage 4:

number

[0155] [Start Pseudo-code 1]

[0156]

number

[0157] [Pseudo-code 1 finished]

[0158] In an NR system, when a single CB is input to an LDPC encoder, parity bits can be added and output. The amount of parity bits can be changed by the LDCP base graph. A method that transmits all parity bits generated by LDPC coding for a given input is called FBRM (full buffer rate matching), while a method that limits the number of transmissible parity bits is called LBRM (limited buffer rate matching). When resources are allocated for data transmission, the LDPC encoder output is created in a circular buffer, and the bits in the created buffer are transmitted repeatedly as many times as the allocated resources. The length of this circular buffer is N. cb It can be done this way.

[0159] If N is the total number of parity bits generated by LDPC coding, then the FBRM method generates N cb =N. Using the LBRM method, N cb is min(N,N ref ) becomes N ref teeth

number

[0160] [Table 13]

[0161] The maximum data rate supported by a terminal in an NR system can be determined via the following equation 2.

number

[0162] In Equation 2, J is the number of carriers combined by frequency aggregation, and R max = 948 / 1024,

number

number

[0163] [Table 14]

[0164] Also,

number

number

number

number

[0165] [Table 15]

[0166] On the other hand, the actual data rate that a terminal can measure during actual data transmission can be the amount of data divided by the data transmission time. This can be the TBS for a 1TB transmission, or the sum of the TBS for a 2TB transmission divided by the TTI length. For example, the maximum actual data rate in a downlink cell with a 30kHz subcarrier spacing and a 100MHz frequency bandwidth, as assumed in Table 15, can be determined by the number of PDSCH symbols allocated, as shown in Table 16 below.

[0167] [Table 16]

[0168] Table 15 allows you to check the maximum data rate supported by the terminal, and Table 16 allows you to check the actual data rate assigned by the TBS. In this case, the actual data rate may be higher than the maximum data rate depending on the scheduling information.

[0169] In wireless communication systems, particularly NR systems, the data rate that a terminal can support can be mutually agreed upon between the base station and the terminal. This can be calculated using the maximum frequency bandwidth, maximum modulation order, and maximum number of layers supported by the terminal. However, the calculated data rate may differ from the value calculated from the TBS and transmission time interval (TTI) length actually used for data transmission.

[0170] This could result in a terminal being assigned a TBS (Time Breakdown Station) larger than the data rate it supports. To prevent this, there may be constraints on the TBS that can be scheduled based on the data rate supported by the terminal.

[0171] Figure 6 is a diagram showing how the synchronization signal (SS) and physical broadcast channel (PBCH) of the NR system are mapped in the frequency and time domains.

[0172] PSS601, SSS603, and PBCH are mapped to 4 OFDM symbols, with PSS and SSS mapped to 12RB and PBCH mapped to 20RB. Figure 6 shows how the frequency bandwidth of 20RB changes depending on the subcarrier spacing (SCS). The resource area to which the above PSS, SSS, and PBCH are transmitted can be called an SS / PBCH block. The above SS / PBCH block can also be called an SSB block.

[0173] Figure 7 is a diagram showing symbols that allow SS / PBCH blocks to be transmitted based on the subcarrier interval.

[0174] Referring to Figure 7, the subcarrier interval can be set to 15kHz, 30kHz, 120kHz, 240kHz, etc., and the position of the symbol where the SS / PBCH block (or SSB block) can be located can be determined by each subcarrier interval. Figure 7 illustrates the position of the symbol where SSB can be transmitted using symbols with a subcarrier interval of 1ms or less, but it does not mean that SSB must always be transmitted in the area shown in Figure 7. The position where the SSB block is transmitted can be set in the terminal via system information or dedicated signaling.

[0175] Since terminals are generally located far from base stations, signals transmitted by terminals are received by the base station after a propagation delay. The propagation delay is the distance the radio waves travel from the terminal to the base station divided by the speed of light; generally, this can be the distance from the terminal to the base station divided by the speed of light. In one example, for a terminal located 100 km away from a base station, a signal transmitted by the terminal is received by the base station approximately 0.34 msec later. Conversely, a signal transmitted by the base station is also received by the terminal approximately 0.34 msec later. As described above, the time it takes for a signal transmitted by a terminal to reach the base station can vary depending on the distance between the terminal and the base station. Therefore, if multiple terminals located in different positions transmit signals simultaneously, the arrival times at the base station can all be different. To solve this problem and ensure that signals transmitted from multiple terminals arrive at the base station simultaneously, the time at which each terminal transmits the uplink signal can be varied depending on its location. In 5G, NR, and LTE systems, this is called timing advance (TA).

[0176] Figure 8 is a diagram showing the processing time of a terminal due to timing advance when a terminal receives a first signal and transmits a second signal in response to it in a 5G or NR system according to one disclosed embodiment.

[0177] The following provides a detailed explanation of the terminal's processing time using Timing Advance. When the base station transmits an uplink scheduling grant (UL grant) or downlink control signal and data (DL grant and DL data) to the terminal in slot n(802), the terminal can receive the uplink scheduling grant or downlink control signal and data in slot n(804). At this time, the terminal receives the signal from the base station with a transmission delay time (T pThe signal can be received approximately 810) later. In this embodiment, if the terminal receives the first signal in slot n (804), the terminal transmits the second signal in slot n+4 (806). When the terminal transmits the signal to the base station, in order to ensure that it arrives at the base station at a specific time, the timing advance (T) is set to be greater than the slot n+4 of the signal referenced by the signal received by the terminal. A 812) The terminal can send a HARQ ACK / NACK for uplink data or downlink data at an earlier timing (806). Therefore, in this embodiment, the time that the terminal can prepare to receive uplink scheduling approval and send uplink data, or to receive downlink data and transmit a HARQ ACK or NACK, is sufficient to be the time corresponding to the three slots excluding the TA (814).

[0178] To determine the timing described above, the base station can calculate the absolute value of the terminal's TA. When the terminal is initially connected, the base station can calculate the absolute value of the TA by adding or subtracting the change in the TA value transmitted to the higher-level signaling to the TA value initially transmitted to the terminal during the random access phase. In this disclosure, the absolute value of the TA may be the value obtained by subtracting the start time of the nth TTI received by the terminal from the start time of the nth TTI transmitted by the terminal.

[0179] On the other hand, one of the important criteria for cellular wireless communication system performance is packet data latency. For this reason, LTE systems transmit and receive signals in subframe units with a TTI of 1 ms. As described above, an LTE system can support terminals with transmission time intervals shorter than 1 ms (short-TTI UE). On the other hand, in 5G or NR systems, the transmission time interval may be shorter than 1 ms. Short-TTI terminals are suitable for services where latency is critical, such as Voice over LTE (VoLTE) services and remote control. Furthermore, short-TTI terminals can be a means of realizing mission-critical Internet of Things (IoT) on a cellular infrastructure.

[0180] In 5G or NR systems, when a base station transmits a PDSCH containing downlink data, the DCI scheduling the PDSCH indicates a K1 value, which corresponds to the timing information for when the terminal transmits the HARQ-ACK information of the PDSCH. The terminal can transmit the HARQ-ACK information to the base station unless it is instructed to transmit it first from symbol L1, including a timing advance. That is, the HARQ-ACK information can be transmitted from the terminal to the base station at the same time as, or after, symbol L1, including a timing advance. If the HARQ-ACK information is instructed to transmit it first from symbol L1, including a timing advance, the HARQ-ACK information may not be valid HARQ-ACK information for transmission from the terminal to the base station.

[0181] Symbol L1 is from the last point in time of PDSCH to T proc,1 It is sufficient if it is the first symbol after which a cyclic prefix (CP) begins. proc,1 This can be calculated using the following formula 3.

[0182] [Numerical]

[0183] In the above-mentioned formula (3), N 1, d 1,1, d 1,2, κ , μ , T C can be defined as follows.

[0184] - When the -HARQ-ACK information is transmitted on the PUCCH (uplink control channel), d 1,1 = 0, and when it is transmitted on the PUSCH (uplink shared channel, data channel), d 1,1 = 1.

[0185] - When there are multiple activated configured carriers or carriers are set for the terminal, the maximum timing difference between carriers can be reflected in the second signal transmission.

[0186] - In the case of PDSCH mapping type A, that is, when the position of the first DMRS symbol is the 3rd or 4th symbol of the slot, and when the position index i of the last symbol of the PDSCH is less than 7, d 1,2 is defined as 7 - i.

[0187] - In the case of PDSCH mapping type B, that is, when the position of the first DMRS symbol is the first symbol of the PDSCH, if the length of the PDSCH is 4 symbols, d 1,2 = 3, and if the length of the PDSCH is 2 symbols, d 1,2 = 3 + d, where d is the number of symbols in which the PDSCH overlaps with the PDCCH including the control signal that schedules the PDSCH.

[0188] - N1 is defined by μ as shown in Table 17 below. μ = 0, 1, 2, 3 mean subcarrier intervals of 15 kHz, 30 kHz, 60 kHz, and 120 kHz respectively.

[0189] [Table 17]

[0190] - The N1 value provided in Table 17 above can be changed depending on the UE capability.

[0191]

number

[0192] Furthermore, in 5G or NR systems, when a base station transmits control information including uplink scheduling approval, it can specify a K2 value that corresponds to the timing information for when a terminal transmits uplink data or PUSCH.

[0193] A PUSCH can be transmitted by the terminal to the base station unless instructed to be transmitted first by symbol L2, including a timing advance. That is, a PUSCH can be transmitted from the terminal to the base station at the same time as or after symbol L2, including a timing advance. If a PUSCH is instructed to be transmitted first by symbol L2, including a timing advance, the terminal can ignore the uplink scheduling acknowledgment control information from the base station.

[0194] Symbol L2 is from the last point in time of the PDCCH, including scheduling approval. proc,2 The CP of any subsequent PUSCH symbols that must be transmitted should be the first symbol that initiates the sequence. proc,2 This can be calculated using the following formula 4.

number

[0195] N in the above formula (4) 2,d 2,1,κ,μ, T C can be defined as follows.

[0196] - When the first symbol among the symbols allocated for PUSCH contains only DMRS, d 2,1 = 0, and otherwise d 2,1 = 1.

[0197] - When multiple activated configured carriers or carriers are set for the terminal, the maximum timing difference between carriers can be reflected in the second signal transmission.

[0198] - N2 is defined by μ as shown in Table 18 below. μ = 0, 1, 2, 3 mean sub - carrier intervals of 15 kHz, 30 kHz, 60 kHz, and 120 kHz respectively.

[0199]

Table 18

[0200] - Other values can be used for the N2 value provided in Table 18 above depending on the UE capability.

Number

[0201] On the other hand, in a 5G or NR system, within one carrier, a frequency band part (BWP) can be set and it can be specified that a specific terminal transmits and receives within the set BWP. This can be for the purpose of reducing the power consumption of the terminal. The base station can set multiple BWPs and can change the BWP activated by the control information. The time that the terminal can use when the BWP is changed can be defined as shown in Table 19 below.

[0202]

Table 19

[0203] In Table 19, Frequency Range 1 refers to the frequency band below 6 GHz, and Frequency Range 2 refers to the frequency band above 6 GHz. In the above-described embodiment, Type 1 and Type 2 can be determined by UE capability. In the above-described embodiment, scenarios 1, 2, 3, and 4 are given as shown in Table 20 below.

[0204] [Table 20]

[0205] Figure 9 is a diagram illustrating an example in which data (e.g., TB) is scheduled and transmitted by slot, HARQ-ACK feedback is received for the data, and retransmission is performed via feedback. In Figure 9, TB1 (900) is initially transmitted in slot 0 (902), and the corresponding ACK / NACK feedback 904 is transmitted from slot 4 (906). If the initial transmission of TB1 fails and a NACK is received, a retransmission (910) of TB1 can be performed in slot 8 (908). The timing of the transmission of the ACK / NACK feedback and the timing of the retransmission can be predetermined or determined by values ​​indicated by control information and / or higher-level signaling.

[0206] Figure 9 illustrates an example where data is scheduled and transmitted sequentially from slot 0 to TB1 through TB8. For example, HARQ process IDs 0 through 7 can be assigned to each of the TB1 through TB8 and transmitted accordingly. However, if the base station and terminal only have four HARQ process IDs available, it may not be possible to transmit to eight other TBs consecutively.

[0207] Figure 10 is a diagram illustrating an example of a communication system using satellites. For example, when terminal 1001 transmits a signal to satellite 1003, satellite 1003 transmits the signal to base station 1005, and base station 1005 processes the received signal and transmits a signal to terminal 1001 that includes a request for subsequent actions, which can then be transmitted via satellite 1003. As described above, the distance between terminal 1001 and satellite 1003 is long, and the distance between satellite 1003 and base station 1005 is also long, so the time required for data transmission and reception from terminal 1001 to base station 1005 is ultimately long.

[0208] Figure 11 is a diagram showing the orbital periods of communication satellites based on their altitude or height. Communication satellites can be classified according to their orbit into Low Earth Orbit (LEO), Middle Earth Orbit (MEO), Geostationary Earth Orbit (GEO), etc. Generally, GEO(1100) refers to satellites at an altitude of approximately 36,000 km, MEO1110 refers to satellites at an altitude of 5,000 to 15,000 km, and LEO refers to satellites at an altitude of 500 to 1,000 km. The orbital period varies depending on the altitude, but for GEO1100, the orbital period is approximately 24 hours, for MEO1110 it is approximately 6 hours, and for LEO1130 it is approximately 90 to 120 minutes. Low Earth Orbit (~2,000 km) satellites have relatively lower altitudes, resulting in more favorable radio delay time and loss compared to geostationary orbit (36,000 km) satellites.

[0209] Figure 12 is a diagram illustrating the concept of direct satellite-terminal communication. Satellite 1200, positioned at an altitude of over 100 km by a rocket, transmits and receives signals with terminal 1210 on the ground, and also transmits and receives signals with a ground station (1220) connected to ground base stations (DU farms, 1230).

[0210] Figure 13 is a diagram illustrating a scenario for utilizing satellite-to-terminal direct communication. Satellite-to-terminal direct communication can support specialized communication services in a way that complements the coverage limitations of terrestrial networks. For example, by implementing satellite-to-terminal direct communication functionality in a user terminal, it becomes possible to send and receive emergency rescue and / or disaster signals in areas not covered by terrestrial network communication (1300), mobile communication services can be provided to users in areas where terrestrial network communication is impossible, such as ships and / or aircraft (1310), the location of ships, cargo vehicles and / or drones can be tracked and controlled in real time without national border restrictions (1320), and satellite communication can also be utilized to perform backhaul functions when physically far away by supporting satellite communication functionality in base stations so that they function as backhaul for the base stations (1330).

[0211] Figure 14 shows an example of calculating the expected data transmission throughput at the uplink when a ground terminal communicates directly with an LEO satellite at an altitude of 1200 km. Assuming an effective isotropic radiated power (EIRP) of 23 dBm at the ground terminal, a path loss of 169.8 dB for the radio channel to the satellite, and a satellite receiving antenna gain of 30 dBi, the achievable signal-to-noise ratio (SNR) is estimated to be -2.63 dB. In this case, path loss can include path loss in space and atmospheric loss. Assuming a signal-to-interference ratio (SIR) of 2 dB, the signal-to-interference and noise ratio (SINR) is calculated to be -3.92 dB. At this time, using a 30 kHz subcarrier spacing and 1 PRB frequency resource, a transmission speed of 112 kbps can be achieved.

[0212] Figure 15 is a diagram illustrating an example of calculating the expected data transmission throughput (SINR) at uplink when a GEO satellite at an altitude of 35,786 km communicates directly with a ground terminal. If the ground terminal's transmit power EIRP at uplink is 23 dBm, the path loss of the radio channel to the satellite is 195.9 dB, and the satellite receiving antenna gain is 51 dBi, the achievable SNR is estimated to be -10.8 dB. In this case, path loss can include path loss in space, atmospheric loss, etc. Assuming an SIR of 2 dB, the SINR is calculated to be -11 dB. At this time, using a 30 kHz subcarrier spacing and 1 PRB frequency resource, a transmission speed of 21 kbps can be achieved, although this may be the result of repeated transmissions as described in step 3.

[0213] Figure 16 is a diagram showing the path loss values ​​based on the path loss model between the terminal and the satellite, and the path loss based on the path loss model between the terminal and the terrestrial network base station. In Figure 16, d corresponds to distance, and f c is the signal frequency. In free space where communication between a terminal and a satellite takes place, the path loss (FSPL, 1600) is inversely proportional to the square of the distance, but on the ground where air exists and communication between a terminal and a terrestrial network base station (terrestrial gNB) takes place, the path loss (PL) is different. 2, PL' Uma-NLOS (1610, 1620) is inversely proportional to the fourth power of the distance.

[0214] In satellite communications (or non-terrestrial networks), a Doppler shift occurs, which is a frequency shift (offset) of the transmitted signal, due to the continuous, rapid movement of the satellite.

[0215] Figure 17 is a diagram showing the formula and result for calculating the amount of Doppler shift that a signal transmitted from a satellite experiences when received by a ground user, based on the satellite's altitude and position, and the position of the ground terminal user. R is the Earth's radius, h is the satellite's altitude, v is the satellite's orbital velocity, and f is the Earth's radius. c θ is the signal frequency. The velocity of the satellite can be calculated from the satellite's altitude, which is the velocity at which the gravitational force (the force with which the Earth pulls the satellite) and the centripetal force generated by the satellite's orbit become equal. This can be calculated as shown in Figure 18. Figure 18 is a diagram showing the satellite's velocity calculated from its altitude. As can be seen in Figure 17, angle α is determined by the elevation angle, and therefore the value of the Doppler shift is determined by the elevation angle θ.

[0216] Figure 19 is a diagram showing the Doppler shift experienced by different terminals within a single beam transmitted from a satellite to the ground. In Figure 19, the Doppler shifts experienced by terminal 1 (1900) and terminal 2 (1910) with respect to the altitude angle θ were calculated. The results are based on the assumption of a central frequency of 2 GHz, a satellite altitude of 700 km, a single beam diameter of 50 km on the ground, and a terminal velocity of 0. Furthermore, the Doppler shift calculated in this invention ignores the effect of the Earth's rotation speed, which can be considered to have little effect because it is slower than the satellite's velocity.

[0217] Figure 20 is a diagram showing the difference in Doppler shift occurring within one beam depending on the satellite's position, which is determined by the altitude angle. It can be seen that the difference in Doppler shift within the beam (or cell) is largest when the satellite is directly above the beam, i.e., when the altitude angle is 90°. This is because when the satellite is in the center, the Doppler shift values ​​at one end of the beam and the other end are positive and negative, respectively.

[0218] On the other hand, satellite communications experience greater latency compared to terrestrial network communications because the satellite is farther away from the user on the ground.

[0219] Figure 21 is a diagram showing the delay time from the terminal to the satellite and the round-trip delay time between the terminal, satellite, and base station, depending on the satellite's position determined by the altitude angle. 2100 represents the delay time from the terminal to the satellite, and 2110 illustrates the round-trip delay time between the terminal, satellite, and base station. In this case, it was assumed that the delay time between the satellite and base station was the same as the delay time between the terminal and satellite. Figure 22 is a diagram showing the maximum difference in round-trip delay time that varies depending on the user's position within a single beam. For example, when the beam radius (or cell radius) is 20 km, the difference in round-trip delay time to the satellite received by terminals at different positions within the beam is estimated to be approximately 0.28 ms or less, depending on the satellite's position.

[0220] The present invention provides a method and apparatus for a terminal that can support both terrestrial network communication and satellite communication, such that the conditions under which the terminal transmits and receives signals differ depending on whether it is terrestrial network communication or satellite communication. To this end, the invention also provides a method and apparatus for the terminal to first distinguish whether the conditions are terrestrial network communication or satellite communication.

[0221] [First Embodiment] The first embodiment provides a method and apparatus for determining whether a terminal is using terrestrial network communication or satellite communication to send or receive a signal.

[0222] Figure 23 is a diagram illustrating an example where a single terminal can perform both terrestrial network communication and satellite-to-terminal direct communication functions. The diagram shows an example where terminal 2300 performs terrestrial network communication and satellite-to-terminal direct communication simultaneously, but in reality, there may be situations where only one of the two can be connected. In Figure 23, an example is shown where terminal 2300 is 2 km away from base station 2320 and 2000 km away from satellite 2310 for terrestrial network communication, and the distance from the base station or satellite can vary depending on the circumstances.

[0223] A terminal may need to distinguish whether a received signal originates from a satellite or from a ground-based base station. This may be for the purpose of selecting a transmitting or receiving or transmitting / receiving antenna, or for determining the transmission power. For this distinction, the terminal may use one or more of the following methods. This method may be used to distinguish the transmission point in the downlink; that is, to determine whether the transmission point is a ground-based base station, or whether the transmission point is a ground-based base station transmitting via satellite, or a satellite-based base station.

[0224] -Method 1: The terminal can know in advance the location of the frequency bands and regions where signals are transmitted and received via terrestrial network communication and satellite communication. For example, frequency Band 1 may be allocated for terrestrial network communication and Band 10 for satellite communication, and the terminal should be able to determine the transmission point based on the frequency bands to which signals are transmitted and received. Of course, this would take into account other frequency allocations on a country-by-country basis. That is, different frequency bands may be allocated to terrestrial network communication and satellite communication on a country-by-country basis, or the same frequency band may be allocated.

[0225] -Method 2: The terminal can determine the transmission point based on its own location. For example, the terminal can know its location and the known coverage of terrestrial network communication or satellite communication, and attempt to connect by selecting a method belonging to that coverage. In this method, the coverage of terrestrial network communication or satellite communication only needs to refer to the geographical area where terrestrial network communication or satellite communication can be performed.

[0226] -Method 3: A sequence of numbers such as PSS, SSS, or PSS and SSS (hereinafter referred to as PSS / SSS) transmitted between a ground base station and a satellite can be used, and the terminal can receive the PSS, SSS, or PSS / SSS and determine whether the transmission point is a base station located on the ground, or a base station located on the ground that transmits via satellite, or a base station located on satellite, etc.

[0227] Using different sequences in this way means using different types of sequences (for example, a ground-based base station may use the M-sequence for the PSS sequence and the Gold sequence for the SSS sequence, but the ground-based base station may transmit the SS via satellite, or a satellite base station may use one or more of the ZC sequence, M-sequence, or Gold sequence for PSS and / or SSS), or using the same type of sequence but the sequences carry different information depending on the transmission point (i.e., the sequences are generated based on different information), or the transmission point transmits the SS at different times and / or with different frequency resources, as long as it is one or more of these combinations.

[0228] When a connection is made based on the aforementioned PSS and / or SSS, the terminal can determine whether the signals transmitted and received by the PSS and / or SSS utilize terrestrial network communication or satellite communication.

[0229] -Method 4: The terminal can distinguish between terrestrial network communication and satellite communication using the spare1 bit (or reserved1 bit) included in the MIB and transmitted. The spare1 bit does not need to be information that the Release15NR terminal receives or interprets. Therefore, only terminals that support both terrestrial network communication and satellite communication can interpret the spare1 bit, and if the value of the spare bit is 0, the MIB can be interpreted as being transmitted using terrestrial network communication, and if it is 1, it can be interpreted as an MIB transmitted using satellite communication. Or the reverse is also possible.

[0230] -Method 5: A specific bit or bit of the SIB1 transmitted from the satellite is fixed to a predetermined value, and when a terminal receives the SIB1, the terminal can determine that the SIB1 was transmitted using satellite communication based on the predetermined value.

[0231] -Method 6: When signals are transmitted and received using satellite communication, a specific SIB is transmitted from the satellite, and the terminal can determine whether satellite communication is taking place by receiving the SIB or by interpreting the bit field of the SIB. For example, SIB14 may contain information on whether the transmission point is related to terrestrial network communication or satellite communication, and SIB14 may also contain detailed setting parameter information related to terrestrial network communication or satellite communication. Such SIB14 is just one example, and other SIBs may also contain the above-mentioned information.

[0232] -Method 7: The terminal determines whether to perform transmission point or satellite communication based on the propagation delay time required for the signal to be transmitted from the transmission point. That is, if the propagation delay time required for the transmission signal from the transmission point is longer than a specific threshold time, the terminal determines that the signal was transmitted using satellite communication, and if the propagation delay time required for the transmission signal from the transmission point is shorter than the specific threshold time, the terminal determines that the signal was transmitted using terrestrial network communication.

[0233] For example, the transmission delay time can be determined based on the difference between the base station's reference time from which the base station transmits a signal and the reference time from which the terminal receives the base station's signal. For example, a base station can include its GPS (global positioning system) reception time and / or location information (hereinafter referred to as base station GPS time information; GPS is merely an example, and this can be understood as information about time and / or location that can be shared between the terminal and the base station; it can also be understood as information about time and / or location based on a specific system) in the system information it transmits to the terminal. Alternatively, a terminal can directly receive a separate GPS signal and set its own reference time (terminal GPS time) upon receiving the GPS signal.

[0234] At this time, if the GPS system and the terminal separately receive GPS signals, the terminal can compare the GPS time information transmitted by the base station (base station GPS time) with the GPS time that the terminal has received and set itself (terminal GPS time) and calculate the radio delay time from the satellite to the terminal or from the terminal to the satellite. In this invention, the GPS system is given as an example, but other GNSS (global navigation satellite system) systems other than GPS can be applied, and in this case, the GNSS system name or type can be indicated by higher-level signaling. The base station can transmit information regarding the reference time to the terminal via higher-level signaling (ReferenceTimeInfo information element) as system information or terminal-specific setting information.

[0235] [Table 21]

[0236] [ReferenceTimeInfo field descriptions]

[0237] -referenceSFN :This field indicates the reference SFN corresponding to the reference time information. If referenceTimeInfo field is received in DLInformationTransfer message,this field indicates the SFN of PCell.

[0238] - time :This field indicates time reference with 10ns granularity. The indicated time is referenced at the network,i. e. ,without compensating for RF propagation delay. The indicated time in 10ns unit from the origin is refDays*86400*1000*100000 + refSeconds*1000*100000 + refMilliSeconds*100000 + refTenNanoSeconds. The refDays field specifies the sequential number of days(with day count starting at 0)from the origin of the time field.

[0239] If the referenceTimeInfo field is received in DLInformationTransfer message,the time field indicates the time at the ending boundary of the system frame indicated by referenceSFN. The UE considers this frame(indicated by referenceSFN)to be the frame which is nearest to the frame where the message is received(which can be either in the past or in the future).

[0240] If the referenceTimeInfo field is received in SIB9,the time field indicates the time at the SFN boundary at or immediately after the ending boundary of the SI-window in which SIB9 is transmitted.

[0241] If referenceTimeInfo field is received in SIB9,this field is excluded when determining changes in system information,i. e. changes of time should neither result in system information change notifications nor in a modification of valueTag in SIB1.

[0242] -timeInfoType:If timeInfoType is not included,the time indicates the GPS time and the origin of the time field is 00:00:00 on Gregorian calendar date 6 January,1980(start of GPS time). If timeInfoType is set to localClock,the origin of the time is unspecified.

[0243] -uncertainty:This field indicates the uncertainty of the reference time information provided by the time field. The uncertainty is 25ns multiplied by this field. If this field is absent,the uncertainty is unspecified.

[0244] In other words, if the timeInfoType value is not set or is not included, the time information can be GPS-based time.

[0245] -Method 8: A terminal can distinguish whether it is transmitting from a point or performing satellite communication using a subscriber identification module (SIM) card used to connect to the system. A terminal can use a SIM card to connect to the system, and depending on whether the SIM card is for terrestrial network communication or satellite communication, the terminal distinguishes between signals transmitted and received for terrestrial network communication or satellite communication.

[0246] -Method 9: The terminal measures the strength (power or energy) of the received signal and determines whether it is a terrestrial network communication or a satellite communication based on this. For example, the terminal can check a predetermined threshold for the strength of the received signal, or one set by the base station, and determine whether the signal is using a terrestrial network communication or a satellite communication based on whether the received signal strength exceeds, is less than, or is the same as the threshold.

[0247] -Method 10: The terminal estimates path loss using the power of the transmitted signal and the strength of the received signal, and determines whether the received signal used terrestrial network communication or satellite communication based on the path loss value. This path loss can be calculated by receiving information on the transmitted power and using the strength of the received signal and the received information on the transmitted power.

[0248] [Second Example] The second embodiment provides a method and apparatus for selecting a transmitting antenna depending on whether the transmitted signal is an uplink transmission in terrestrial network communication or an uplink transmission in satellite communication when a terminal is transmitting a signal. The following describes the method by which the terminal selects a transmitting antenna, but this can also be applied to the method by which the terminal selects a receiving antenna.

[0249] Figure 24 is a diagram showing the structure and location of the terminal's transmitting and receiving antennas. Each antenna can transmit and receive, but depending on the operation method of the terminal, it can be designed to transmit or receive only. In the case of a terrestrial network communication terminal, the second antenna 2410 located on the bottom is used for both transmission and reception, while the first antenna 2400 located on the top, where the telephone speaker is located, is used for reception only in most cases. The reason for this is that if the first antenna 2400 is used as a transmitting antenna, the radio waves have a significant impact on the human body, especially the head. In terrestrial network communication, even if the second antenna 2410 located on the bottom of the terminal is used as a transmitting antenna, the radio waves can spread horizontally and be received by the base station, so there may be no difference compared to using the first antenna 2400 located on the top of the terminal as a transmitting antenna.

[0250] On the other hand, in the case of satellite communication, since the satellite is located above the terminal, any method that minimizes path loss or increases antenna gain by transmitting with an antenna located above the terminal is acceptable. Therefore, basically, the method provided in the first embodiment of the present invention for confirming whether satellite communication is being performed on the terminal can be used. When it is confirmed that satellite communication is being performed, the first antenna 2400, which is the antenna on the upper side of the terminal, can be used when the terminal transmits a signal (via satellite), and the second antenna 2410, which is the antenna on the lower side of the terminal, can be used when the terminal transmits a signal using terrestrial network communication.

[0251] On the other hand, the user can adjust the orientation of the terminal as they see fit. Therefore, when satellite communication is performed, the antenna used for transmission from the terminal may be an antenna located on the top of the terminal, or it may be an antenna located closer to the sky (or the satellite's position) using the gyroscope sensor included in the terminal.

[0252] Figure 25 is a diagram illustrating an example of a user arbitrarily adjusting the orientation of the terminal. For example, if the terminal is positioned upside down as shown in Figure 25, the terminal could transmit a signal using the second antenna 2410 for satellite communication. Of course, if the terminal is upside down as shown in Figure 25, the terminal could also transmit a signal using the second antenna 2410 for terrestrial network communication.

[0253] A gyroscope sensor is a sensor that can detect the current orientation of a device by utilizing rotational moment of inertia, which is a type of inertial force. It can also be said to be a sensor that can detect the x, y, and z axis directions and / or acceleration along the x, y, and z axes of the device, regardless of the detection method.

[0254] Figure 26 is a diagram illustrating how a terminal determines the antenna to be used for communication. As illustrated in Figure 26, the terminal includes a step 2600 in which it determines whether or not it is a satellite communication environment when selecting an antenna to be used for signal transmission, and the operation of such a step can be performed by at least one combination of the methods described in the first embodiment. Based on the determination, it can be decided which antenna to use to transmit the signal. For example, if the terminal transmits the signal via satellite, the terminal can use an antenna located near the satellite to transmit the signal (2610), and if the terminal transmits the signal to a ground station, the terminal can use an antenna located below the terminal (which may be fixed or vary depending on the direction of the terminal) to transmit the signal (2620).

[0255] [Third Embodiment]

[0256] The third embodiment provides a method for displaying to the user that a terminal supporting satellite network communication has connected to a base station via satellite when the terminal connects to a base station via satellite.

[0257] When a terminal connects to a base station via satellite, the terminal can notify that it has connected to the satellite network by displaying a satellite icon on its screen (or display). The fact that a terminal has connected to the satellite network can be confirmed when the base station transmits information to the terminal after the connection that it has connected to the satellite network. Alternatively, the terminal can be determined to have connected to the satellite network using the method provided in the first embodiment described above.

[0258] Furthermore, when the terminal connects to the satellite network, the user may be provided with information related to the satellite network. This information may include, for example, information regarding the charges the user must pay when making a voice and / or video call, or when transmitting data. This information may be displayed when data is uploaded or downloaded, or at the moment the user presses the call button, or at the moment the call begins.

[0259] [Fourth embodiment] The fourth embodiment provides a method for searching for frequencies in the process of a terminal supporting terrestrial and satellite network communications finding a base station signal.

[0260] If a terminal supports multiple frequency bands, it can choose which frequency to search first. Searching for a frequency, in this context, simply means the process of finding a synchronization signal. During this frequency search process, the terminal may have prior information on the frequency bands used for satellite network communication and the frequency bands used for terrestrial network communication. In this case, the terminal can search for the frequency band used for terrestrial network communication first. This is because terrestrial network communication generally performs better than satellite network communication.

[0261] Another example is that after exploring all frequency bands, the terminal can compare the strength of signals transmitted by the satellite in each frequency band (for example, the signal strength only needs to be the strength of at least one synchronization signal or reference signal transmitted by the satellite, and the signal to be measured can be predetermined. Such signal strengths can be measured in dBm and compared to a predetermined or predetermined threshold value) and first attempt to connect to a base station in the frequency band with the highest signal strength. Subsequently, if the attempted base station connection is unsuccessful, it can try to connect to a base station in another frequency band. When the terminal compares signal strengths, in the case of a terrestrial network communication frequency band, it may add an offset value and compare it to the signal strength of a satellite network communication frequency band. If the base station connection is unsuccessful as described above, it may be because the terminal cannot receive a signal from the base station within a certain time using a random access procedure, or it may not be able to receive an acknowledgment signal (e.g., msg4) containing its own ID value. For example, if the signal strength or signal-to-noise ratio of the terrestrial network communication frequency band is A, and the signal strength or signal-to-noise ratio of the satellite network communication frequency band is B, the terminal can directly compare A and B and select the terrestrial or satellite network frequency band to attempt connection. However, as mentioned above, if A+alpha is greater than or equal to B, the terminal will attempt to connect to a base station in the terrestrial network communication frequency band. If B is greater, it will attempt to connect to a base station in the satellite network communication frequency band. This is because terrestrial network communication generally has lower latency and may not exhibit the Doppler effect compared to satellite network communication, thus allowing for more stable communication, and thus the actual signal strength can be considered greater.

[0262] The terminal attempts to connect to the base station in the selected frequency band. For example, if the terminal selects a terrestrial network communication frequency band using the method described above, it receives a synchronization signal or SSB to obtain synchronization with the base station, then receives the MIB and SIB to obtain configuration information, and then performs a random access process. The terminal transmits a PRACH preamble to the base station using the terrestrial network and receives a RAR from the base station. Subsequently, the terminal transmits Msg3 based on the TA value and UL grant included in the received RAR and receives Msg4 from the base station.

[0263] For example, if a terminal selects a frequency band for satellite network communication, it will behave similarly to if it selected a frequency band for terrestrial network communication. In this case, the terminal may set the RAR window length (which can be understood as the time the terminal attempts to detect DCI using RA-RNTI) to a value greater than 10ms after sending the PRACH preamble. This can be set by system information, and the start of the RAR window should be in the PDCCH region where the first RAR after the PRACH preamble can be transmitted.

[0264] Although the first to fourth embodiments of the present invention were described separately above for the sake of convenience, each embodiment includes operations that relate to one another, so it is also possible to construct a system by combining at least two or more embodiments.

[0265] To carry out the above-mentioned embodiments of the present invention, the transmitting unit, receiving unit, and processing unit of the terminal and base station are illustrated in Figures 27 to 28, respectively. In order to perform the operations for determining the transmission and reception of signals in the first to fourth embodiments, the transmitting and receiving methods of the base station and terminal are shown, and in order to do so, the receiving unit, processing unit, and transmitting unit of the base station and terminal must operate according to the respective embodiments.

[0266] Specifically, Figure 27 is a block diagram illustrating the internal structure of a terminal according to an embodiment of the present invention. As shown in Figure 27, the terminal of the present invention may include a terminal receiving unit 2700, a terminal transmitting unit 2720, and a terminal processing unit 2710. In the embodiment of the present invention, the terminal receiving unit 2700 and the terminal transmitting unit 2720 can be collectively referred to as the transceiver unit. The transceiver unit can transmit and receive signals with a base station. The signal may include control information and data. For this purpose, the transceiver unit may consist of an RF transmitter that converts and amplifies the frequency of the transmitted signal, and an RF receiver that low-noise amplified the received signal and converts its frequency down. The transceiver unit can also receive signals via a wireless channel and output them to the terminal processing unit 2710, and transmit signals output from the terminal processing unit 2710 via the wireless channel. The terminal processing unit 2710 can control a series of processes so that the terminal operates according to the embodiments of the present invention described above. For example, the terminal receiving unit 2700 receives a signal from a satellite or ground base station, and the terminal processing unit 2710 determines whether the received signal was received from a satellite or ground base station using the method described in the present invention, and can determine the antenna to transmit the signal based on this determination. Thereafter, the terminal transmitting unit 2720 can transmit the signal using the determined antenna. The terminal may also include a sensor (e.g., a gyroscope) to determine the direction of the terminal.

[0267] Figure 28 is a block diagram showing the internal structure of a base station according to an embodiment of the present invention. As shown in Figure 28, the base station of the present invention may include a base station receiving unit 2800, a base station transmitting unit 2820, and a base station processing unit 2810. The base station may be a ground base station or part of a satellite. The base station receiving unit 2800 and the base station transmitting unit 2820 may collectively be referred to as the transceiver unit in the embodiment of the present invention. The transceiver unit can transmit and receive signals to and from a terminal. The signals may include control information and data. For this purpose, the transceiver unit may consist of an RF transmitter that converts and amplifies the frequency of the transmitted signal, and an RF receiver that low-noise amplified the received signal and converts its frequency down. The transceiver unit can also receive signals via a radio channel and output them to the base station processing unit 2810, and transmit signals output from the base station processing unit 2810 via a radio channel. The base station processing unit 2810 can control a series of processes so that the base station operates according to the above-described embodiment of the present invention. For example, the base station processing unit 2810 can transmit signals to a terminal if necessary based on the setting information it has set. For example, a base station can transmit different signals to a terminal from itself, a ground base station, or a satellite.

[0268] Figure 29 is a block diagram showing the internal structure of a satellite according to an embodiment of the present invention. As shown in Figure 29, the satellite of the present invention may include a satellite receiving unit 2900, a satellite transmitting unit 2920, and a satellite processing unit 2910. Although the receiving unit, transmitting unit, and processing unit are shown singly above, they can be composed of multiple units. For example, the satellite receiving unit 2900 and the satellite transmitting unit 2920 may each consist of a receiving unit and a transmitting unit for sending and receiving signals with a terminal, and a receiving unit and a transmitting unit for sending and receiving signals with a base station. In this embodiment of the present invention, the satellite receiving unit 2900 and the satellite transmitting unit 2920 may collectively be referred to as the satellite transmitting and receiving unit. The transmitting and receiving unit can send and receive signals with terminals and base stations. The signals may include control information and data. For this purpose, the transmitting and receiving unit may consist of an RF transmitter that converts and amplifies the frequency of the transmitted signal upwards, and an RF receiver that low-noise amplified the received signal and converts its frequency downwards. The transmitting and receiving unit can also receive signals via a wireless channel and output them to the satellite processing unit 2910, and transmit signals output from the satellite processing unit 2910 via a wireless channel. The satellite processing unit 2910 may include a compensator (pre-compensator) for compensating for frequency offset or Doppler shift, and may include a device for tracking the satellite's position using a system such as GPS. The satellite processing unit 2910 may also include a frequency shift function that can shift the center frequency of the received signal. The satellite processing unit 2910 can control a series of processes so that the satellite, base station, and terminal operate according to the embodiments of the present invention described above. For example, the satellite receiving unit 2900 can receive a PRACH preamble from a terminal and, while further transmitting the RAR based on this to the terminal, decide to transmit the information to the base station. Thereafter, the satellite transmitting unit 2920 can transmit the signal at the determined time.

[0269] On the other hand, the embodiments of the present invention disclosed in this specification and drawings are presented as specific examples to facilitate the explanation of the technical content of the present invention and to aid in its understanding, and are not intended to limit the scope of the present invention. In other words, it is obvious to a person with ordinary skill in the art to which the present invention belongs that modifications based on the technical idea of ​​the present invention are possible. Furthermore, each of the embodiments can be combined and operated as needed. In addition, other modifications based on the technical idea of ​​the embodiments may be implemented in LTE systems, 5G systems, etc. [Explanation of symbols]

[0270] 102 OFDM Symbols 104 N BW Subcarrier 106 slots 108 resource blocks 110 N RB Subcarrier 112 Resource Elements 114 Radio Frame

Claims

1. A method performed by a terminal in a communication system, The stage of receiving a signal using a frequency band, If the frequency band is a frequency band for NTN (non-terrestrial network), the step of determining that the signal was received using the NTN, The steps include receiving a system information block (SIB) for the aforementioned NTN, Includes, The SIB for the NTN includes time information relating to the satellite providing services to the terminal, The method is characterized in that the time information is reference time information, indicated using SFN (system frame number), and is for a specific cell of the terminal.

2. The method according to claim 1, characterized in that the SIB for the NTN includes location information of the satellite providing services to the terminal.

3. The method according to claim 1, characterized in that the SIB for the NTN includes information for a RAR window for receiving RAR (random access response) messages.

4. A method performed by a node supporting the NTN (non-terrestrial network) of a communication system, The step of deciding whether to transmit a signal using the aforementioned NTN, When the signal is transmitted to the terminal using the NTN, the steps include: transmitting the signal using the frequency band for the NTN; The process includes the step of transmitting a system information block (SIB) for the aforementioned NTN, The SIB for the NTN includes time information relating to the satellite providing services to the terminal, The method is characterized in that the time information is reference time information, indicated using SFN (system frame number), and is for a specific cell of the terminal.

5. The method according to 4, characterized in that the SIB for the NTN includes location information of the terminal that provides services to the terminal.

6. The method according to 4, characterized in that the SIB for the NTN includes information for a RAR window for receiving RAR (random access response) messages.

7. A terminal in a communication system, Transmitter / receiver unit, Receiving signals using frequency bands, The system includes, if the frequency band is a frequency band for an NTN (non-terrestrial network), a control unit that determines that the signal was received using the NTN and controls the system to receive a system information block (SIB) for the NTN. The SIB for the NTN includes time information relating to the satellite providing services to the terminal, The aforementioned time information is reference time information, indicated using SFN (system frame number), and is characterized in that it is for a specific cell of the terminal.

8. The terminal according to claim 7, characterized in that the SIB for the NTN includes location information of the terminal that provides services to the terminal.

9. The terminal according to claim 7, wherein the SIB for the NTN includes information for a RAR window for receiving RAR (random access response) messages.

10. A node that supports NTN (non-terrestrial network) in a communication system, Transmitter / receiver unit, Decide whether to transmit a signal using the aforementioned NTN, When the signal is transmitted to a terminal using the NTN, the system includes a control unit that controls the transmission of the signal using the frequency band for the NTN and the transmission of a system information block (SIB) for the NTN, The SIB for the NTN includes time information relating to the satellite providing services to the terminal, The node is characterized in that the aforementioned time information is reference time information, indicated using SFN (system frame number), and is for a specific cell of the terminal.

11. The node according to claim 10, wherein the SIB for the NTN includes location information of the terminal that provides services to the terminal.

12. The node according to claim 10, wherein the SIB for the NTN includes information for a RAR window for receiving RAR (random access response) messages.

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