Method and apparatus for transmitting an uplink channel in a wireless communication system

Abstract

According to an embodiment of the present disclosure, a method of operating a user equipment (UE) to estimate a channel based on repeatedly transmitted physical uplink shared channels (PUSCH) may include: receiving, from a base station (BS), repeated transmission configuration information for repeatedly transmitting PUSCH; receiving, from the BS, frequency hopping configuration information including configuration information on a hopping interval between a plurality of frequency resources for transmitting PUSCH; and repeatedly transmitting PUSCH to the BS while performing frequency hopping at the hopping interval based on the repeated transmission configuration information and the frequency hopping configuration information.

Description

Technical Field

[0001] The present disclosure provides a method for a base station or a user equipment in a wireless communication system to configure an uplink channel. Background Art

[0002] In order to meet the ever-growing demand for wireless data services since the commercialization of 4G communication systems, efforts have been made to develop advanced fifth-generation (5G) systems or pre-5G communication systems. For this purpose, 5G or pre-5G communication systems are also referred to as ultra-fourth-generation (4G) network communication systems or post-long term evolution (LTE) systems. The 5G communication system defined by the Third Generation Partnership Project (3GPP) is called the New Radio (NR) system. The implementation of a 5G communication system using the ultra-high frequency (millimeter wave (mmWave)) band (e.g., 60 gigahertz (GHz) band) is being considered to obtain higher data transmission rates. In order to reduce the path loss of radio waves and increase the transmission range of radio waves in the ultra-high frequency band, beamforming, massive multiple-input multiple-output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and massive antenna technologies are being discussed for the 5G communication system and applied to the NR system. In order to improve the system network, technologies for advanced small cells, cloud radio access network (RAN), ultra-dense network, device-to-device (D2D) communication, wireless backhaul, mobile network, cooperative communication, coordinated multi-point (CoMP), receiver interference cancellation, etc. are also being developed in the 5G communication system. In addition, in the 5G system, advanced coding modulation (ACM) schemes such as hybrid frequency shift keying FSK and quadrature amplitude modulation QAM modulation (FQAM), sliding window superposition coding (SWSC), and advanced access technologies such as filter bank multicarrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) are being developed.

[0003] Meanwhile, the Internet is evolving from a human-oriented connection network for generating and consuming information by humans to an Internet of Things (IoT) network where distributed entities or things send, receive, and process information without human intervention. Internet of Everything (IoE) technologies have also emerged, for example, through the combination of big data processing technologies connected to cloud servers and IoT technologies. To implement IoT, various technologies are required, such as sensing technologies, wired / wireless communication and network infrastructure, service interface technologies, and security technologies. Even technologies for sensor networks, machine-to-machine (M2M) communication, and machine type communication (MTC) for connections between things are currently being studied. In the IoT environment, intelligent Internet technology (IT) services can be provided, which create new value for human life by collecting and analyzing data generated from connected things. Through the integration and combination of existing information technology (IT) and various industrial applications, IoT can be applied to various fields, such as smart homes, smart buildings, smart cities, smart cars or connected vehicles, smart grids, healthcare, smart appliances, and advanced medical services.

[0004] In this regard, various attempts are being made to apply 5G communication systems to IoT networks. For example, technologies related to sensor networks, M2M, MTC, etc. are realized through 5G communication technologies such as beamforming, MIMO, array antenna schemes, etc. The application of cloud radio access network (cloud RAN) as the above-mentioned big data processing technology may also be an example of the integration of 5G and IoT technologies. Summary of the Invention

[0005] Technical Problem

[0006] The present disclosure provides a method and apparatus for transmitting an uplink channel in a wireless communication system.

[0007] Technical Solution

[0008] According to an embodiment of the present disclosure, a method of operating a user equipment (UE) to estimate a channel based on repeatedly transmitted physical uplink shared channels (PUSCHs) may include: receiving, from a base station (BS), repetition transmission configuration information for repeatedly transmitting a PUSCH; receiving, from the BS, frequency hopping configuration information including configuration information on a hopping interval between a plurality of frequency resources for transmitting the PUSCH; and repeatedly transmitting the PUSCH to the BS while performing frequency hopping at the hopping interval based on the repetition transmission configuration information and the frequency hopping configuration information. According to an embodiment of the present disclosure, a method of operating a BS to estimate a channel based on repeatedly transmitted PUSCHs may include: transmitting, to the UE, repetition transmission configuration information for repeatedly transmitting a PUSCH; transmitting, to the UE, frequency hopping configuration information including configuration information on a hopping interval between a plurality of frequency resources for transmitting the PUSCH; repeatedly receiving, from the UE, the repeatedly transmitted PUSCH while performing frequency hopping at the hopping interval based on the repetition transmission configuration information and the frequency hopping configuration information; and estimating the channel by simultaneously using at least one demodulation reference signal (DMRS) included in the repeatedly received PUSCHs.

[0009] Through the method of configuring frequency resources of an uplink channel suitable for a transmission environment proposed by the present disclosure, the BS or the UE transmits an uplink channel among various frequency resources, thereby making it possible to improve uplink channel reception performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 Shows a basic structure of a time - frequency domain, which is a radio resource domain for transmitting data or a control channel in a fifth - generation (5G) system.

[0011] Figure 2 Shows a slot structure considered in a 5G system.

[0012] Figure 3 Is a view for describing demodulation reference signal (DMRS) patterns (type 1 and type 2) for communication between a base station (BS) and a user equipment (UE) in a 5G system.

[0013] Figure 4 Shows an example of channel estimation using DMRS received in one physical uplink shared channel (PUSCH) in the time domain in a 5G system.

[0014] Figure 5 Shows an example of channel estimation using DMRS received in multiple PUSCHs in the time domain in a 5G system.

[0015] Figure 6 Shows an example of PUSCH repetition transmission type B in a 5G system.

[0016] Figure 7 It is a flowchart for describing the operation of a UE configured with a hopping interval pattern according to an embodiment of the present disclosure.

[0017] Figure 8 It is a flowchart for describing another operation of a UE configured with a hopping interval pattern according to an embodiment of the present disclosure.

[0018] Figure 9 It is a flowchart for describing another operation of a UE configured with a hopping interval pattern according to an embodiment of the present disclosure.

[0019] Figure 10 It shows a frequency hopping method as an example in PUSCH retransmission type B according to an embodiment of the present disclosure.

[0020] Figure 11 It shows a frequency hopping method as another example in PUSCH retransmission type B according to an embodiment of the present disclosure.

[0021] Figure 12 It shows a frequency hopping method as another example in PUSCH retransmission type B according to an embodiment of the present disclosure.

[0022] Figure 13 It shows a frequency hopping method as another example in PUSCH retransmission type B according to an embodiment of the present disclosure.

[0023] Figure 14 It shows a frequency hopping method as another example in PUSCH retransmission type B according to an embodiment of the present disclosure.

[0024] Figure 15 It shows a DMRS position switching method in PUSCH retransmission type B according to an embodiment of the present disclosure.

[0025] Figure 16 It shows another DMRS position switching method in PUSCH retransmission type B according to an embodiment of the present disclosure.

[0026] Figure 17 It is a flowchart showing a UE operation method according to an embodiment of the present disclosure.

[0027] Figure 18 It is a flowchart showing a BS operation method according to an embodiment of the present disclosure.

[0028] Figure 19 It is a block diagram of a UE according to an embodiment of the present disclosure.

[0029] Figure 20 It is a block diagram of a BS according to an embodiment of the present disclosure. Detailed implementation manners

[0030] Embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Technical content that is well known in the art or not directly related to the present disclosure is omitted in the following description of the embodiments of the present disclosure. By omitting content that may obscure the subject matter of the present disclosure, the subject matter will be more clearly understood.

[0031] For the same reason, some components in the drawings are exaggerated, omitted, or shown schematically. The sizes of the respective elements may not exactly reflect their actual sizes. In all the drawings, the same numerals refer to the same elements.

[0032] When reading the following embodiments with reference to the accompanying drawings, the advantages and features of the present disclosure and the methods for realizing them will be more clearly understood. However, the embodiments of the present disclosure can be implemented in many different forms and should not be construed as limited to the embodiments set forth herein; in contrast, these embodiments of the present disclosure are provided so that the present disclosure will be thorough and complete, and the scope of the embodiments of the present disclosure will be fully conveyed to those of ordinary skill in the art. In the description of the present disclosure, when it is determined that a detailed description of related functions or configurations may unnecessarily obscure the subject matter of the present disclosure, the detailed description will be omitted. In addition, as will be mentioned later, these terms are defined by considering the functions in the present disclosure, but these terms may vary according to the practice or intention of the user or operator. Therefore, these terms should be defined based on the description throughout the specification.

[0033] In the following description, a base station is an entity for performing resource allocation for a terminal and may be at least one of a gNB, an eNB, a Node B, a base station (BS), a radio access unit, a base station controller, and a network node. A terminal may include a user equipment (UE), a mobile station (MS), a cellular phone, a smart phone, a computer, or a multimedia system capable of performing communication functions. Herein, a downlink (DL) refers to a radio transmission path of a signal sent from a BS to a UE, and an uplink (UL) refers to a radio transmission path of a signal sent from a UE to a BS. Although the following embodiments will focus on a Long Term Evolution (LTE) or an LTE-Advanced (LTE-A) system as an example, they can be applied to other communication systems having a similar technical background or channel type. For example, the fifth-generation (5G) mobile communication technology developed since LTE-A, such as 5G New Radio (NR), may be included in a system to which the embodiments of the present disclosure will be applied, and the term "5G" used herein may be a concept including existing LTE, LTE-A, or other similar services. In addition, the embodiments of the present disclosure will also be applied to different communication systems with some modifications that, when judged by those skilled in the art, will not significantly deviate from the scope of the present disclosure.

[0034] It can be understood that each box and combination of boxes in the process flow diagram will be executed by computer program instructions. The computer program instructions can be loaded onto the processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that when executed by the processor of the computer or other programmable data processing device, they generate means for performing the functions described in the boxes of the flow diagram. The computer program instructions can also be stored in a computer-executable or computer-readable memory oriented to the computer or other programmable data processing device, so as to run in a specific manner. Thus, a product can be manufactured that includes instructions stored in the computer-executable or computer-readable memory for performing the functions described in the boxes of the flow diagram. The computer program instructions can also be loaded onto the computer or programmable data processing device, so that the instructions can generate a process executed by the computer or other programmable data processing device to provide steps for performing the functions described in the boxes of the flow diagram.

[0035] In addition, each box can represent a module, segment, or part of code that includes one or more executable instructions to perform a specific logical function. Note that in some alternative embodiments, the functions described in the boxes may not occur in sequence. For example, depending on the corresponding functions, two consecutive boxes can be executed substantially simultaneously or in the reverse order.

[0036] As used herein, the term "module" (or sometimes "unit") refers to a software or hardware component that performs some function, such as a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC). However, the module is not limited to software or hardware. The module can be configured to be stored in an addressable storage medium or to execute on one or more processors. For example, a module can include components such as software components, object-oriented software components, class components, and task components, processes, functions, attributes, procedures, subroutines, program code segments, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functions provided by the components and modules can be combined into a smaller number of components and modules, or further divided into a larger number of components and modules. In addition, the components and modules can be implemented as one or more central processing units (CPUs) in an execution device or a secure multimedia card. In an embodiment, the module can include one or more processors.

[0037] Embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The methods and apparatuses proposed in the embodiments of the present disclosure will now be described by taking enhanced PUSCH coverage as an example, but are not limited thereto, and combinations of all or some of one or more embodiments of the present disclosure can be used to configure methods for frequency resources corresponding to other channels. In addition, when judged by those of ordinary skill in the art, the embodiments of the present disclosure will also be applied to a degree that does not deviate significantly from the scope of the present disclosure through some modifications.

[0038] In the description of the present disclosure, when it is determined that a detailed description of a related function or configuration may unnecessarily obscure the subject matter of the present disclosure, the detailed description will be omitted. In addition, as will be mentioned later, these terms are defined by considering the functions in the present disclosure, but may vary according to the practice or intention of a user or operator. Therefore, these terms should be defined based on the description throughout the specification.

[0039] Wireless communication systems are evolving from early systems that provided voice-oriented services to broadband wireless communication systems that provide high data rate and high-quality packet data services, such as Third Generation Partnership Project (3GPP) High Speed Packet Access (HSPA), LTE or Evolved Universal Terrestrial Radio Access (E-UTRA), LTE-A, LTE-Pro, 3GPP2 High Speed Packet Data (HRPD), Ultra Mobile Broadband (UMB), and IEEE802.16e communication standards.

[0040] As a representative example of such a broadband wireless communication system, the LTE system uses Orthogonal Frequency Division Multiplexing (OFDM) for DL and Single Carrier Frequency Division Multiple Access (SC-FDMA) for UL. UL refers to the radio link for a UE or MS to send data or control signals to an eNode B (eNB) or BS, and DL refers to the radio link for a BS to send data or control signals to a UE or MS. Such a multiple access scheme allocates and operates time-frequency resources for carrying data or control information for each user so that they do not overlap with each other, that is, maintain orthogonality, thereby distinguishing the data or control information of each user.

[0041] A 5G communication system, as a communication system since LTE, needs to support services that can simultaneously meet various requirements to freely reflect various requirements from users and service providers. Services considered for the 5G communication system may include Enhanced Mobile Broadband (eMBB), Massive Machine Type Communication (mMTC), Ultra-Reliable Low-Latency Communication (URLLC), etc.

[0042] eMBB aims to provide higher data rates than what LTE, LTE-A, or LTE-Pro may support. For example, in a 5G communication system, according to a single BS, eMBB is required to provide a peak data rate of 20 Gbps in the DL and 10 Gbps in the UL. In addition, the 5G communication system needs to provide an increased user-perceived data rate when providing the peak data rate. To meet these requirements, various techniques for transmission or reception may need to be enhanced, including multi-input multi-output (MIMO) transmission techniques. While the LTE system uses a maximum transmission bandwidth of 20 MHz in the 2 GHz frequency band for signal transmission, the 5G communication system can use a frequency bandwidth wider than 20 MHz in the 3 to 6 GHz frequency band or a frequency band of 6 GHz or higher, thereby meeting the data rates required by the 5G communication system.

[0043] Meanwhile, in a 5G communication system, mMTC is considered to support application services such as the Internet of Things (IoT). To enable mMTC to effectively provide IoT, it is necessary to support access from a large number of UEs in a cell, enhanced coverage of terminals, extended battery life, reduced terminal prices, etc. Since IoT is equipped in various sensors and devices to provide communication functions, it can support a large number of UEs in a cell (e.g., 1,000,000 terminals / km 2 ). In addition, UEs supporting mMTC are more likely to be located in shadow areas, such as the basements of buildings, which may not be covered by the cell due to the nature of the service. Therefore, mMTC requires greater coverage than expected for other services provided by the 5G communication system. UEs supporting mMTC need to be low-cost UEs and require a relatively long battery life, such as 10 to 15 years, because the batteries in UEs are difficult to replace frequently.

[0044] Finally, URLLC is a cellular-based critical mission wireless communication service. For example, URLLC can provide services for remote control of robots or machines, industrial automation, unmanned aerial vehicles, remote healthcare, emergency alerts, etc. Therefore, the communication provided by URLLC requires very low latency and very high reliability. For example, the URLLC service may need to meet an air interface latency of sub-milliseconds (less than 0.5 milliseconds), while requiring a packet error rate equal to or lower than 10 -5 . Therefore, for the URLLC service, the 5G system needs to provide a smaller transmission time interval (TTI) than other services and, at the same time, needs to allocate a large range of resources for the frequency band to ensure the reliability of the communication link.

[0045] These three services of a 5G communication system (hereinafter, interchangeably used with the 5G system), namely, eMBB, URLLC, and mMTC, can be multiplexed and transmitted from a single system. In such a case, different transmission or reception schemes and parameters can be used between the services to meet the different requirements of the three services.

[0046] The frame structure in the 5G system will now be described in more detail with reference to the accompanying drawings.

[0047] Figure 1 The basic structure of the time-frequency domain as the radio resource domain of the 5G system according to an embodiment of the present disclosure is shown.

[0048] In Figure 1 , the horizontal axis represents the time domain and the vertical axis represents the frequency domain. The basic resource unit in the time domain and the frequency domain is a resource element (RE) 101, which can be defined as an orthogonal frequency division multiplexing (OFDM) symbol or a discrete Fourier transform spread OFDM (DFT-s-OFDM) 102 in the time domain and a subcarrier 103 in the frequency domain. In the frequency domain, (e.g., 12) consecutive REs can form a single resource block (RB) 104. In the time domain, consecutive OFDM symbols can form a single subframe 110.

[0049] Figure 2 The slot structure considered in the 5G system is shown.

[0050] In Figure 2 , an example of the structures of a frame 200, a subframe 201, and a slot 202 is shown. A frame 200 can be defined as 10 ms long. A subframe 201 can be defined as 1 ms, so a total of 10 subframes 201 can form a frame 200. A slot 202 or 203 can be defined as having 14 OFDM symbols (i.e., the number of symbols per slot ). A subframe 201 can include one or more slots 202 and 203, and the number of slots 202 and 203 in each subframe can vary according to the subcarrier spacing configuration values μ 204 and 205.

[0051] In Figure 2 's example, the slot structures in the cases where the subcarrier spacing configuration values are 0 and 1, i.e., μ = 0 (204) and μ = 1 (205), are shown. In the case of μ = 0 (204), a subframe 201 includes one slot 202, while in the case of μ = 1 (205), a subframe 201 includes two slots 203. That is, depending on the subcarrier spacing configuration value μ, the number of slots in each subframe can vary, and the number of slots in each frame It can change accordingly. Depending on the subcarrier spacing configuration value μ and can be defined in Table 1 below.

[0052] [Table 1]

[0053]

[0054] Now, the demodulation reference signal (DMRS), one of the reference signals in the 5G system, will be described in detail.

[0055] The DMRS to be described below refers to a reference signal that has the characteristic of undergoing UE-specific precoding and is transmitted to enable the UE to perform demodulation without receiving additional precoding information. The DMRS can include several DMRS ports, and these ports use code division multiplexing (CDM) or frequency division multiplexing (FDM) to maintain orthogonality to prevent mutual interference. However, based on the intention and purpose of the user using the reference signal, the term DMRS can be represented by other names. Specifically, the term DMRS is merely an example for more clearly explaining the present disclosure and helping to understand the present disclosure, and is not limited thereto. Therefore, it is obvious to those of ordinary skill in the art that based on the technical concept of the present disclosure, the present disclosure is also applicable to other reference signals.

[0056] Figure 3 is a view for describing the DMRS modes (Type 1 and Type 2) used for communication between the BS and the UE in the 5G system.

[0057] In the 5G system, two DMRS modes are supported. Figure 3 These two DMRS modes are shown in detail. Refer to Figure 3 , reference numerals 301 and 302 indicate DMRS Type 1, where 301 indicates a one-symbol pattern and label 302 indicates a two-symbol pattern. In Figure 3 , DMRS Type 1 301 and 302 are DMRS modes in a comb 2 structure, which can include two code division modulation (CDM) groups, and different CDM groups are frequency division modulated (FDMed). Specifically, in Figure 3 for 301 and 302, the horizontal striped part indicates CDM group 0, and the vertical striped part indicates CDM group 1.

[0058] In Figure 3 the one-symbol pattern of 301, two DMRS ports can be distinguished by applying CDM in frequency to the same CDM group. Therefore, a total of 4 orthogonal DMRS ports can be configured. In Figure 3In 301, the DMRS port IDs mapped to each CDM group are shown (for DL, the DMRS port ID is represented by adding +1000 to the shown number). In Figure 3 In the two-symbol pattern of 302, four DMRS ports can be distinguished by applying CDM in time / frequency to the same CDM group. Therefore, a total of 8 orthogonal DMRS ports can be configured. In 302, the DMRS port IDs mapped to each CDM group are shown (for DL, the DMRS port ID is represented by adding +1000 to the shown number).

[0059] On the other hand, Figure 3 The DMRS type 2 in 303 and 304 is a structured DMRS pattern in which a frequency domain orthogonal cover code (FD-OCC) is applied to adjacent subcarriers in frequency, which can include three CDM groups, and different CDM groups are frequency division modulated. Specifically, referring to Figure 3 In 303 and 304, the slanted part indicates CDM group 0, the horizontally striped part indicates CDM group 1, and the vertically striped part indicates CDM group 2.

[0060] In Figure 3 In the one-symbol pattern of 303, two DMRS ports can be distinguished by applying CDM in frequency to the same CDM group. Therefore, a total of 6 orthogonal DMRS ports can be configured. In Figure 3 In 303, the DMRS port IDs mapped to each CDM group are shown (for DL, the DMRS port ID is represented by adding +1000 to the shown number). In Figure 3 In the two-symbol pattern of 304, four DMRS ports can be distinguished by applying CDM in time / frequency to the same CDM group. Therefore, a total of 12 orthogonal DMRS ports can be configured. In Figure 3 In 304, the DMRS port IDs mapped to each CDM group are shown (for DL, the DMRS port ID is represented by adding +1000 to the shown number).

[0061] As described above, in the NR system, two different DMRS patterns can be configured ( Figure 3either 301 and 302 or 303 and 304), and it is also possible to configure whether the DMRS pattern is a single-symbol pattern (301 and 303) or an adjacent two-symbol pattern (302 and 304). In addition, in the NR system, not only is the DMRS port number set and signaled to be scheduled, but the number of CDM groups is also scheduled for PDSCH rate matching. In addition, in the case of cyclic prefix-based orthogonal frequency division multiplexing (CP-OFDM), for both DL and UL, the above two DMRS patterns can be supported, while in the case of discrete Fourier transform spread OFDM (DFT-S-OFDM), for UL, only DMRS type 1 of the above DMRS patterns can be supported. In addition, configurable additional DMRS can be supported. The front-loaded DMRS refers to the first DMRS that appears in the symbol that is the earliest in time, while the additional DMRS refers to the DMRS that appears in the symbols after the front-loaded DMRS. In the NR system, the number of additional DMRS can be set from a minimum of 0 to a maximum of 3. In addition, when configuring the additional DMRS, the same pattern as the front-loaded DMRS is assumed. Specifically, for the front-loaded DMRS, when information about whether the above DMRS pattern type is type 1 or type 2, information about whether the DMRS pattern is a single-symbol pattern or an adjacent two-symbol pattern, and information about the number of CDM groups used for the DMRS port is indicated, the DMRS information can be configured such that the additional DMRS is equal to the front-loaded DMRS when additionally configured.

[0062] More specifically, the aforementioned DL DMRS and UL DMRS configurations can be configured through the RRC signaling in Tables 2 and 3 below.

[0063] [Table 2]

[0064]

[0065] [Table 3]

[0066]

[0067]

[0068] Figure 4 Shows an example of channel estimation using DMRS received in one physical uplink shared channel (PUSCH) in the time domain in a 5G system.

[0069] For channel estimation for data decoding by using the aforementioned DMRS, a PRB bundling associated with a system domain can be used in the frequency domain to perform channel estimation in a precoding resource block group (PRG) as a bundling unit. Further, in a time unit, the channel is estimated by assuming that the DMRS received only in one PUSCH has the same precoding. Thus, the channel estimation in the time domain is limited.

[0070] Figure 5 An example of channel estimation using the DMRS received in multiple PUSCHs in the time domain in a 5G system is shown.

[0071] The BS can indicate whether the UE is to use the same precoding by configuration, and using this indication, the BS can estimate the channel by jointly using the DMRS transmissions using the same precoding, thereby improving the DMRS channel estimation performance. As in Figure 4 even in Figure 5 for channel estimation for data decoding by using the aforementioned DMRS, the PRB bundling associated with the system domain can be used in the frequency domain to perform channel estimation in the PRG as a bundling unit. Additionally, in a time unit, the channel is estimated by assuming that the DMRS received only in one or more PUSCHs has the same precoding. This can improve the channel estimation performance because it is possible to estimate the channel based on various DMRSs in the time domain. Especially for improving coverage, the channel estimation performance may be very critical because even with good data decoding performance, the channel estimation performance may be a bottleneck.

[0072] Now, a time domain resource allocation method for a data channel in 5G communication will be described.

[0073] The BS can configure the UE with a time domain resource allocation information table for a DL data channel (physical downlink shared channel, PDSCH) and a UL data channel (physical uplink shared channel, PUSCH) by using higher layer signaling (e.g., RRC signaling).

[0074] For PDSCH, the BS may configure a table including up to 16 (maxNrofDL - Allocations = 16) entries, and for PUSCH, a table including up to 16 (maxNrofDL - Allocations = 16) entries may be configured. The time - domain resource allocation information may include, for example, the slot timing from PDCCH to PDSCH (corresponding to the time interval in the slot between the PDCCH reception time and the PDSCH transmission time scheduled on the received PDCCH, denoted as K0), the slot timing from PDCCH to PUSCH (corresponding to the time interval in the slot between the PDCCH reception time and the PUSCH transmission time scheduled on the received PDCCH, denoted as K2), information about the length and position of the start symbol in the slot scheduled on PDSCH or PUSCH, the mapping type of PDSCH or PUSCH, etc. For example, the information in the following table may be notified from the BS to the UE.

[0075] [Table 4]

[0076]

[0077] [Table 5]

[0078]

[0079] The BS may notify one of the entries of the table of time - domain resource allocation information to the UE through L1 signaling (e.g., in DCI, especially in the "time - domain resource allocation" field of DCI). The UE may obtain the time - domain resource allocation information of PDSCH or PUSCH based on the DCI received from the BS.

[0080] Now, the repeated transmission on the UL data channel (e.g., PUSCH) in the 5G system will be described in detail.

[0081] In 5G, two types of UL data channel repeated - transmission methods are supported, namely, PUSCH repeated - transmission type A and PUSCH repeated - transmission type B.

[0082] PUSCH Repeated - Transmission Type A

[0083] - As described above, in the time - domain resource allocation method, the start symbol and length of the UL data channel can be determined in the slot, and the BS may notify the number of repeated transmissions to the UE through higher - layer signaling (e.g., RRC signaling) or L1 signaling (e.g., DCI).

[0084] - The UE repetitively transmits a UL data channel having the same start symbol and length as the configured UL data channel in consecutive time slots based on the number of repeated transmissions received from the BS. In such a case, when a time slot configured as DL for the UE or at least one UL data channel symbol configured for the UE is set to DL, the UE skips UL data channel transmission. In other words, the UE counts the number of repeated transmissions of the UL data channel but does not perform the transmission.

[0085] PUSCH Repetition Type B

[0086] - As described above, in the time domain resource allocation method, the start symbol and length of the UL data channel can be determined in a time slot, and the BS can notify the UE of the number of repeated transmissions via higher layer signaling (e.g., RRC signaling) or L1 signaling (e.g., DCI).

[0087] - Based on the start symbol and length of the previously configured UL data channel, the nominal repetition of the UL data channel is determined as follows: The time slot at which the n-th nominal repetition starts is given by and the start symbol in that time slot is given by Here, n = 0,..., numberofrepetitions - 1, S represents the start symbol of the configured UL data channel, and L represents the symbol length of the configured UL data channel. K s represents the time slot at which PUSCH transmission starts, and represents the number of symbols per time slot.

[0088] - The UE determines the invalid symbols for PUSCH repetition transmission type B. The symbols set to DL by tdd-UL-DL-ConfigurationCommon (TDD UL-DL common configuration) or tdd-UL-DL-ConfigurationDedicated (TDD UL-DL dedicated configuration) are determined as the invalid symbols for PUSCH repetition transmission type B. In addition, the invalid symbols can be configured in higher layer parameters (e.g., InvalidSymbolPattern). The higher layer parameter (e.g., InvalidSymbolPattern) can provide a symbol-level bitmap spanning one or two time slots to configure the invalid symbols. In the bitmap, '1' represents an invalid symbol. In addition, the period and pattern of the bitmap can be configured in higher layer parameters (e.g., periodicityAndPattern). When the higher layer parameter (e.g., InvalidSymbolPattern) is configured and the parameter InvalidSymbolPatternIndicator-ForDCIFormat0_1 (invalid symbol pattern indicator for DCI format 0_1) or InvalidSymbolPatternIndicator-ForDCIFormat0_2 (invalid symbol pattern indicator for DCI format 0_2) indicates '1', the UE applies the invalid symbol pattern, and when the parameter indicates '0', the UE does not apply the invalid symbol pattern. When the higher layer parameter (e.g., InvalidSymbolPattern) is configured and the parameter InvalidSymbolPatternIndicator-ForDCIFormat0_1 or InvalidSymbolPatternIndicator-ForDCIFormat0_2 is not configured, the UE applies the invalid symbol pattern.

[0089] - After determining the invalid symbols in each nominal repetition, the UE can consider the remaining symbols as valid symbols. When one or more valid symbols are included in each nominal repetition, the nominal repetition can include one or more actual repetitions. Each actual repetition includes a set of consecutive valid symbols for PUSCH repetition transmission type B in one time slot.

[0090] Figure 6 An example of PUSCH repetition transmission type B in the 5G system is shown.

[0091] When the start symbol S of the UL data channel is configured as "0" for the UE, the length L of the UL data channel is "14", and the number of repeated transmissions is "16", nominal repetition (601) can be performed in 16 consecutive time slots. To determine the invalid symbols, the UE can determine the symbol set of the DL symbols in each nominal repetition as the invalid symbols, and determine the symbols set to 1 in the invalid symbol pattern (602) as the invalid symbols. When there is one or more consecutive valid symbols in the time slot in addition to the invalid symbols in each nominal repetition, the valid symbols can be set as the actual repetitions and transmitted (603).

[0092] Now, the frequency hopping on the UL data channel (e.g., PUSCH) in the 5G system will be described in detail.

[0093] 5G supports two methods for each PUSCH retransmission type as the frequency hopping method on the UL data channel. PUSCH retransmission type A supports intra-slot frequency hopping and inter-slot frequency hopping, and PUSCH retransmission type B supports inter-repetition frequency hopping and inter-slot frequency hopping.

[0094] The intra-slot frequency hopping method supported in PUSCH retransmission type A is a method in which the UE performs transmission by changing the configured frequency offset of the resources allocated in the frequency domain at two hopping positions in one time slot. In intra-slot frequency hopping, the starting RB for each hop is given as where i = 0 and i = 1 represent the first hop and the second hop respectively, and RB start represents the starting RB in the UL bandwidth part (BWP) and is calculated according to the frequency resource allocation method. RB offset represents the frequency offset between the two hops of the higher layer parameter. The number of symbols for the first hop can be represented by and the number of symbols for the second hop can be represented by is the length of the PUSCH transmission in one time slot and is represented by the number of OFDM symbols.

[0095] The inter-slot frequency hopping method supported in PUSCH retransmission types A and B is a method in which the UE performs transmission by changing the configured frequency offset of the resources allocated in the frequency domain in each time slot. In intra-slot frequency hopping, the starting RB is given as during the time slot represents the current time slot number in the multi-time slot PUSCH transmission, and RB start represents the starting RB in the UL BWP and is calculated according to the frequency resource allocation method. RB offset represents the frequency offset between the two hops of the higher layer parameter.​

[0096] The frequency hopping method supported in PUSCH repetition transmission type B is a method in which a UE performs transmission by changing the frequency offset configured in each actual PUSCH for the resources allocated in the frequency domain.

[0097] According to the present disclosure, by performing frequency hopping by considering a method of estimating a channel by simultaneously using DMRS transmitted in multiple PUSCHs, both the channel estimation performance and the channel diversity gain in the frequency domain can be improved, thereby improving the UL reception performance and UL coverage. The present disclosure will now be described through specific embodiments.

[0098] <First Embodiment>

[0099] The first embodiment of the present disclosure is directed to a frequency hopping method that considers a method of estimating a channel by simultaneously using DMRS transmitted in multiple PUSCHs. By using a frequency hopping method that considers a method of estimating a channel by simultaneously using DMRS transmitted in multiple PUSCHs, a channel diversity gain can be obtained in the frequency domain, and the channel estimation performance can be improved.

[0100] Specifically, when DMRS from multiple PUSCHs are transmitted on the same frequency domain resource, a method of estimating a channel by simultaneously using DMRS transmitted in multiple PUSCHs can be used. Therefore, when estimating a channel by simultaneously using DMRS transmitted in multiple PUSCHs, it is difficult to obtain a channel diversity gain in the frequency domain through frequency hopping. Similarly, in the case of existing frequency hopping methods available in NR, since hopping is performed in each time slot or each repetition transmission in a time slot, which results in different frequency domain resources allocated for multiple PUSCH transmissions, the channel may not be estimated simultaneously based on DMRS transmitted in multiple PUSCHs.

[0101] Therefore, in order to obtain a channel diversity gain and improve the channel estimation performance in the frequency domain, it may be necessary to apply a frequency hopping method that considers a method of estimating a channel by simultaneously using DMRS transmitted in multiple PUSCHs. For this purpose, as a frequency hopping method that considers a method of estimating a channel by simultaneously using DMRS transmitted in multiple PUSCHs, the following method is proposed:

[0102] [Method 1]

[0103] The BS may configure a hopping interval for the UE to estimate the channel by simultaneously using DMRS sent in multiple PUSCHs. The rule or configuration on the hopping interval will now be referred to as the interval pattern. The BS may configure the hopping interval for the UE via higher layer signaling, L1 signaling, or both. Since the repeated transmissions are skipped in the resources where UL transmission cannot be performed, the resources where UL transmission cannot be performed may be dynamically changed in NR. Therefore, for an interval pattern, under dynamic UL transmission conditions, the channel can be estimated without configuring a suitable hopping pattern by simultaneously using DMRS sent in multiple PUSCHs.

[0104] As a method for the BS to configure the hopping interval for the UE, the following methods may be considered:

[0105] Figure 7 、 Figure 8 and Figure 9 are flowcharts for describing the operations of a UE configured with a hopping interval pattern according to an embodiment of the present disclosure.

[0106] Referring to Figure 7 In operation 701, the UE may be configured with an interval pattern by the BS via higher layer signaling. In operation 702, the UE may receive hopping configuration information from the BS via higher layer signaling or L1 signaling. In operation 703, the UE may perform hopping based on the configured interval pattern to send a PUSCH to the BS.

[0107] Referring to Figure 8 In operation 801, the UE may be configured with an interval pattern by the base station based on the number of repeated transmissions via higher layer signaling. In operation 802, the UE may receive hopping configuration information from the BS via higher layer signaling or L1 signaling. In operation 803, the UE may be configured with the number of repeated transmissions by the BS via L1 signaling. In operation 804, the UE may perform hopping based on the interval pattern corresponding to the configured number of repeated transmissions to send a PUSCH to the BS.

[0108] Referring to Figure 9 In operation 901, the UE may be configured with multiple interval patterns via higher layer signaling. In operation 902, the UE may receive hopping configuration information from the BS via higher layer signaling or L1 signaling. In operation 903, the UE may be configured with one of the multiple interval patterns by the BS via L1 signaling. In operation 904, the UE may perform hopping based on the configured hopping interval pattern to send a PUSCH.

[0109] In this way, the UE can be configured with a hopping interval pattern via L1 signaling, and the UE can perform frequency hopping and send a PUSCH to the BS. As described above, the BS can configure the hopping interval for the UE to estimate the channel by using the DMRS sent in multiple PUSCHs when performing frequency hopping. In such a case, the hopping interval can be determined by the following method:

[0110] [Method 1-1]

[0111] The interval pattern of frequency hopping can be configured in a time slot. When the interval pattern for frequency hopping is configured in a time slot, after receiving the interval pattern information for frequency hopping, the UE can send a PUSCH by performing frequency hopping without additional determination.

[0112] Figure 10 FIG. shows a frequency hopping method as an example in PUSCH retransmission type B according to an embodiment of the present disclosure. Refer to Figure 10 , when the UE is configured such that the start symbol S of the UL data channel is "0", the length L of the UL data channel is "14", and the number of retransmissions is "16", nominal retransmission (1001) can be performed in 16 consecutive time slots.

[0113] Then, when determining invalid symbols, the UE can determine the symbol set of the DL symbols in each nominal retransmission as invalid symbols. When there are one or more consecutive valid symbols in a time slot instead of the invalid symbols in each nominal retransmission, the valid symbols can be configured for the actual retransmission, and a total of 9 actual retransmissions (1002) can be sent.

[0114] When the UE is configured with an interval pattern for frequency hopping of three time slots and five time slots, the first three time slots can be sent in the first hop (1003), the next five time slots can be sent in the second hop (1004), and repeatedly, the next three time slots can be sent back in the first hop (1005), and the next five time slots can be sent back in the second hop (1006). The resources determined to be valid symbols in the configured hops can be set to the actual retransmission number and sent. Method 1-1 can be similarly applied to PUSCH retransmission type A.

[0115] [Method 1-2]

[0116] The interval pattern of frequency hopping can be configured in the nominal retransmission. When the interval pattern of frequency hopping is configured in the nominal retransmission, the UE can send a PUSCH by determining what actual retransmissions are included in the nominal retransmission and performing frequency hopping after receiving the interval pattern information for frequency hopping.

[0117] Figure 11Shows a frequency hopping method as another example in PUSCH repetition transmission type B according to an embodiment of the present disclosure. Refer to Figure 11 , when the UE is configured with the start symbol S of the UL data channel being "9", the length L of the UL data channel being "10", and the number of repetition transmissions being "16", 16 consecutive nominal repetitions can be performed, each having 10 OFDM symbols (1101).

[0118] Then, when determining the invalid symbols, the UE can determine the symbol set of the DL symbols in each nominal repetition as the invalid symbols. When there are one or more consecutive valid symbols in the time slot instead of the invalid symbols in each nominal repetition, the valid symbols can be configured for the actual repetitions, and a total of 12 actual repetitions can be sent (1102).

[0119] When the UE is configured with an interval pattern for frequency hopping of 5 nominal repetitions and 6 nominal repetitions, the UE can send the actual repetitions included in the first five of the nominal repetitions configured for repetition transmission in the first hop (1103), send the actual repetitions included in the next six nominal repetitions in the second hop (1104), and repeatedly send back the actual repetitions included in the next 5 nominal repetitions in the first hop (1105). The resources determined to be valid symbols in the configured hops can be set as actual repetitions and sent.

[0120] [Method 1-3]

[0121] The interval pattern of frequency hopping can be configured in the actual repetitions. In the case where the interval pattern of frequency hopping is configured in the actual repetitions, the UE can send the PUSCH by determining what actual repetitions are included in the nominal repetitions and performing frequency hopping after receiving the interval pattern information for frequency hopping.

[0122] Figure 12 Shows a frequency hopping method as another example in PUSCH repetition transmission type B according to an embodiment of the present disclosure. Refer to Figure 12 , when the UE is configured with the start symbol S of the UL data channel being "9", the length L of the UL data channel being "10", and the number of repetition transmissions being "16", 16 consecutive nominal repetitions can be performed, each having 10 OFDM symbols (1201).

[0123] Then, when determining the invalid symbols, the UE can determine the symbol set of the DL symbols in each nominal repetition as the invalid symbols. When there are one or more consecutive valid symbols in the time slot instead of the invalid symbols in each nominal repetition, the valid symbols can be configured for the actual repetitions, and a total of 12 actual repetitions can be sent (1202).

[0124] When the UE is configured with an interval pattern for frequency hopping of 3 actual repetitions and 6 actual repetitions, the UE may transmit the first three actual repetitions (1103) configured for repeated transmission in the first hop, the next six actual repetitions (1104) in the second hop, and repeat the next three actual repetitions (1105) in the first hop. Resources determined to be valid symbols in the configured hops may be set to the number of actual repetitions and transmitted.

[0125] [Method 2]

[0126] Frequency hopping may be performed by making the start symbol / slot and period of the UL-DL TDD configuration setting in the TDD system the same as those of the frequency hopping pattern. Basically, consecutive UL resources may be determined in a time slot / symbol according to the UL-DL TDD configuration setting. Therefore, by making the start symbol / slot and period of the UL-DL TDD configuration setting the same as those of the frequency hopping pattern, the consecutive UL resources in the UL-DL TDD configuration setting may be transmitted in the same frequency hop.

[0127] Figure 13 A frequency hopping method is shown as another example in PUSCH repeated transmission type B according to an embodiment of the present disclosure. Refer to Figure 13 , when the UE is configured with the start symbol S of the UL data channel being "0", the length L of the UL data channel being "14", and the number of repeated transmissions being "16", nominal repetition (1301) may be performed in 16 consecutive time slots.

[0128] Then, when determining invalid symbols, the UE may determine the symbol set of the DL symbols in each nominal repetition as invalid symbols. When there are one or more consecutive valid symbols instead of invalid symbols in a time slot in each nominal repetition, the valid symbols may be configured for actual repetition, and a total of 9 actual repetitions may be transmitted (1302).

[0129] When the UE is configured with a frequency hopping pattern to have the same start symbol / slot and period as the UL-DL TDD configuration, TDD configuration 1 is set to DDDSU (1303), and TDD configuration 2 is set to DDSUU (1304), the start symbol / slot and period of the first hop of the frequency hopping may be the same as those in the symbol / slot configuring TDD configuration 1, and the start symbol / slot and period of the second hop may be set to be the same as those in the symbol / slot configuring TDD configuration 2. Similarly, the symbol / slot configured for the next TDD configuration 1 may be configured to be transmitted in the first hop, and the symbol / slot configured for TDD configuration 2 may be configured to be transmitted in the second hop.

[0130] Resources determined to be valid symbols in the configured hopping can be set to be actually repeated and transmitted. This can be equally applied to PUSCH repetition transmission type A. The method proposed in Method 2 is described with a cell-specific UL-DL TDD configuration, but is not limited thereto, and can also be used based on a slot format indicator (SFI) that can be configured in DCI or a UE-specific UL-DL TDD configuration.

[0131] [Method 3]

[0132] The UE can perform frequency hopping on each consecutive PUSCH transmission in the time domain. In the case of performing frequency hopping on each consecutive PUSCH transmission, the UE and the BS can send and receive the PUSCH by performing frequency hopping without additional frequency hopping pattern information.

[0133] Specifically, when two PDSCHs have a gap of less than a specific N symbols in the time domain, it can be determined as consecutive PUSCH transmissions. The specific N symbols can be determined based on a minimum gap condition that allows estimating the channel by simultaneously using DMRS sent in multiple PUSCHs. When performing PUSCH transmission through two actual repetitions, the UE can calculate the number of symbols between the two PUSCH transmissions, and keep the hopping of the frequency hopping the same when the number of symbols is less than N, and change the hopping of the frequency hopping when the number of symbols is larger.

[0134] Figure 14 A frequency hopping method is shown as another example in PUSCH repetition transmission type B according to an embodiment of the present disclosure. Refer to Figure 14 , when the UE is configured with the start symbol S of the UL data channel being "0", the length L of the UL data channel being "14", and the number of repeated transmissions being "16", nominal repetition (1401) can be performed in 16 consecutive time slots.

[0135] To determine invalid symbols, the UE can then determine the symbol set of the DL symbols in each nominal repetition as invalid symbols, and determine the symbols set to 1 in the invalid symbol pattern as invalid symbols (1402). When there are one or more consecutive valid symbols instead of invalid symbols in each nominal repetition in a time slot, it can be configured and transmitted as actual repetitions 1403, 1404, 1405, 1406, 1407, 1408, 1409, and 1410.

[0136] Assume that the OFDM symbol gap that does not require hopping handover during frequency hopping between PUSCH transmissions corresponds to 7 symbols. For the first actual repetition 1403, PUSCH can be transmitted in the first hop. For the second actual repetition 1404, there is a hopping handover, and PUSCH can be transmitted in the second hop. Since the second actual repetition 1404 is 37 symbols away from the first actual repetition 1403 in the time domain, the gap between PUSCHs has more than 7 symbols. For the third actual repetition 1405, PUSCH can be transmitted in the second hop because there is no symbol gap from the second actual repetition 1404 in the time domain. For the fourth actual repetition 1406, there is a hopping handover, and PUSCH can be transmitted in the first hop because the fourth actual repetition 1406 is 9 symbols away from the third actual repetition 1405 in the time domain, which exceeds the 7-symbol gap between PUSCHs. Similarly, the fifth, sixth, seventh, and eighth actual repetitions 1407, 1408, 1409, and 1410 can also experience hopping handovers for frequency hopping based on the symbol gap between PUSCHs and then be transmitted.

[0137] [Method 4]

[0138] The BS can configure a bitmap to determine the hopping of frequency hopping so that the UE performs frequency hopping. Although directly configuring the UE for frequency hopping by the BS with a bitmap has high overhead, it can be flexibly configured for appropriate frequency hopping on any occasion through the bitmap configuration. When the bitmap for determining the hopping of frequency hopping has a "0", it indicates the first hop, while when the bitmap has a "1", it indicates the second hop. In another method, when the bitmap represents "0", it can indicate that the transmission will be performed without hopping handover, and when the bitmap represents "1", it can indicate that the transmission will be performed by changing the existing hop to another hop. In such a case, the unit indicated by one bit in the bitmap can be determined by the following method:

[0139] [Method 4-1]

[0140] The unit indicated by one bit in the bitmap for frequency hopping can be configured in a time slot. In the case where the bits in the bitmap are configured in a time slot, after receiving the bitmap for frequency hopping, the UE can transmit PUSCH by performing frequency hopping without additional determination.

[0141] Assume that "0" in the bitmap for determining the hopping of frequency hopping indicates the first hop, and "1" in the bitmap indicates the second hop, then Figure 10 the bitmap in can be represented by a total of 16 bits: 0001111100011111. In such a case, in Figure 10In [the above], the first three time slots (1003) can be transmitted in the first hop, the next five time slots (1004) can be transmitted in the second hop, and repeatedly, the next three time slots can be transmitted back in the first hop (1005), and the next five time slots can be transmitted back in the second hop (1006).

[0142] In addition, assuming that '0' in the bit map of the hops used to determine frequency hopping indicates that the transmission will be performed without a hop switch, and '1' in the bit map indicates that the transmission will be performed by changing the existing hop to another hop, then Figure 10 the bit map in [the above] can be represented by a total of 16 bits: 0001000010010000. The resources determined to be valid symbols in the configured hops can be set to actual repetitions and transmitted. Method 4-1 can be similarly applied to PUSCH repetition transmission type A.

[0143] [Method 4-2]

[0144] The unit indicated by one bit in the bit map for frequency hopping can be configured in nominal repetition. In the case where the bit in the bit map is configured in nominal repetition, the UE can transmit the PUSCH by determining what actual repetitions are included in the nominal repetition and performing frequency hopping after receiving the bit map for frequency hopping.

[0145] Assuming that '0' in the bit map of the hops used to determine frequency hopping indicates the first hop, and '1' in the bit map indicates the second hop, then Figure 11 the bit map in [the above] can be represented by a total of 16 bits: 000001111100000. In such a case, in Figure 11 the case of [the above], the actual repetitions included in the first five of the nominal repetitions configured for repeated transmission can be transmitted in the first hop (1103), the actual repetitions included in the next six nominal repetitions can be transmitted in the second hop (1104), and the repeated actual repetitions included in the next five nominal repetitions can be transmitted back in the first hop (1105).

[0146] In addition, assuming that '0' in the bit map of the hops used to determine frequency hopping indicates that the transmission will be performed without a hop switch, and '1' in the bit map indicates that the transmission will be performed by changing the existing hop to another hop, then Figure 11 the bit map in [the above] can be represented by a total of 16 bits: 0000010000010000. The resources determined to be valid symbols in the configured hops can be set to actual repetitions and transmitted.

[0147] [Method 4-3]

[0148] The unit indicated by a bit in the bitmap for frequency hopping can be configured in actual repetitions. In the case where the bits in the bitmap are configured in actual repetitions, the UE can transmit the PUSCH by determining what actual repetitions are included in the nominal repetition and performing frequency hopping after receiving the bitmap for frequency hopping.

[0149] Assume that "0" in the bitmap for determining the hops of frequency hopping indicates the first hop, and "1" in the bitmap indicates the second hop. Then Figure 12 the bitmap of can be represented by a total of 12 bits: 000111111000. In such a case, in Figure 12 the first three actual repetitions configured for repeated transmission can be sent in the first hop (1203), the next six actual repetitions can be sent in the second hop (1204), and repeatedly, the next three actual repetitions can be sent back in the first hop (1205).

[0150] In addition, assume that "0" in the bitmap for determining the hops of frequency hopping indicates that the transmission will be performed without hop switching, and "1" in the bitmap indicates that the transmission will be performed by changing the existing hop to another hop. Then Figure 12 the bitmap in can be represented by a total of 12 bits: 000100000100. Therefore, the resources determined to be valid symbols in the configured hops can be set as actual repetitions and transmitted.

[0151] <Second Embodiment>

[0152] The second embodiment of the present disclosure is directed to a method of changing the OFDM symbol position of DMRS when performing channel estimation by simultaneously using DMRS transmitted in multiple PUSCHs. When it is possible to perform channel estimation by simultaneously using DMRS transmitted in multiple PUSCHs, the OFDM symbol positions of DMRS may be inefficiently arranged. Especially in the case of PUSCH repeated transmission type B, since the number of symbols for actual repetitions is not fixed and the OFDM symbol positions of DRMS can be serially configured because they always have a front-loaded DMRS configuration, it ends with an inefficient arrangement of the OFDM symbols of DMRS in channel estimation. By using the method of changing the OFDM symbol position of DMRS described in the embodiment, the channel estimation performance based on the same number of DMRS OFDM symbols can be improved, or the decoding performance can be improved for a low channel coding rate obtained by reducing the number of DMRS OFDM symbols.

[0153] Specifically, for PUSCH transmission, in the case of front-loaded DMRS configuration, the DMRS needs to be transmitted in the first OFDM symbol of the PUSCH configured as described above. In such a case, in the foremost PUSCH in consecutive PUSCH repeated transmissions with front-loaded DMRS configuration, additional DMRS can be configured in the last symbol or near the last symbol in time. Since subsequent PUSCH transmissions also have front-loaded DMRS configuration, the DMRS is configured in the symbol immediately following the DMRS configured in the last symbol of the previous PUSCH. Therefore, when the channel can be estimated by simultaneously using DMRS sent from multiple PUSCHs, channel estimation can be performed more effectively by changing the OFDM symbol positions of the DMRS so that the OFDM symbol positions of the DMRS are arranged more evenly.

[0154] In the present disclosure, considering a method of estimating the channel by simultaneously using DMRS sent in multiple PUSCHs, the following method is proposed as a method of changing the OFFDM symbol positions of the DMRS:

[0155] [Method 1]

[0156] When the channel can be estimated by simultaneously using DMRS sent in multiple PUSCHs, the OFDM symbol positions of the DMRS can be configured by changing the existing PUSCH mapping type to a new PUSCH mapping type. In PUSCH mapping type A, the start symbol of the PUSCH is always fixed to the first symbol of the time slot, while in PUSCH mapping type B, the DMRS is always fixed to the first symbol of the PUSCH. Therefore, in the case of PUSCH repeated transmission type B, since the PUSCH may not be transmitted in the first symbol of the time slot, it is always fixed to PUSCH mapping type B, resulting in the OFDM symbol of the DMRS being configured with inefficient positioning as described above.

[0157] To solve this problem, a new PUSCH mapping type can be configured in which the DMRS is not allocated in the first symbol of the PUSCH as in PUSCH mapping type A, and the resources allocated to the PUSCH can be performed anywhere in the time slot as in PUSCH mapping type B. When the restriction of configuring the PUSCH from the first symbol of the time slot in PUSCH mapping type A is lifted, the restriction of determining the DMRS position based on the first symbol of the time slot can also be lifted. Therefore, the channel can be estimated by simultaneously using DMRS sent in multiple PUSCHs, and in the case of PUSCH repeated transmission type B, the PUSCH can be configured in the new PUSCH mapping type.

[0158] Figure 15Shows a method for switching DMRS positions in PUSCH repetition transmission type B according to an embodiment of the present disclosure. Refer to Figure 15 , when the UE is configured with the start symbol S of the UL data channel being "9", the length L of the UL data channel being "10", and the number of repeated transmissions being "2", two consecutive nominal repetitions can be performed, each having 10 OFDM symbols (1501).

[0159] After determining the invalid symbols, the UE can send the PUSCH in three actual repetitions. In such a case, for the first three consecutive PUSCHs, the OFDM symbol of the DMRS can be located in the first symbol of each PUSCH, and for the PUSCH with 5 symbols, the DMRS can be located in the last symbol (1502). As in the foregoing method, considering the new PUSCH mapping type, where, as in PUSCH mapping type A, no DMRS is allocated in the first symbol of the PUSCH, and as in PUSCH mapping type B, the resources allocated to the PUSCH can be performed anywhere in the time slot, there is no restriction that needs to be configured starting from the first symbol of the time slot in PUSCH mapping type A, and the DMRS position can be determined not limited to the first symbol of the time slot. In such a case, in three consecutive PUSCHs, the DMRS can be sent in the third symbol, the eighth symbol, the thirteenth symbol, and the eighteenth symbol (1503). This can enable the PUSCH to be sent at a lower channel coding rate, while there is no significant difference in channel estimation performance compared to the existing transmission of 6 DMRS OFDM symbols.

[0160] [Method 2]

[0161] The OFDM symbol position of the DMRS can be configured by treating consecutive actual repeated PUSCHs as a single nominal repeated PUSCH. When configuring consecutive PUSCHs with a small number of symbols, such inefficient DMRS symbol positioning as described above may occur. Therefore, when the nominal repetition is divided into two actual repetitions by the time slot boundary, the PUSCHs in the two actual repetitions can be treated as the PUSCHs in a single nominal repetition to configure the DMRS OFDM symbols, rather than configuring the DMRS OFDM symbols for each PUSCH in the two actual repetitions.

[0162] Figure 16 Shows another method for switching DMRS positions in PUSCH repetition transmission type B according to an embodiment of the present disclosure. Refer to Figure 16 , when the UE is configured with the start symbol S of the UL data channel being "9", the length L of the UL data channel being "10", and the number of repeated transmissions being "2", two consecutive nominal repetitions may occur, each repetition having 10 OFDM symbols (1501).

[0163] After determining the invalid symbol, the UE can send the PUSCH in 3 actual repetitions. In such a case, for the first three consecutive PUSCHs, the OFDM symbol of the DMRS can be located in the first symbol of each PUSCH. For a PUSCH with 5 symbols, the DMRS can be located in the last symbol (1602). When configuring the DMRS OFDM symbol position by treating the PUSCHs in the nominal repetitions as a single PUSCH as in the foregoing method, two actual repetition PUSCHs each having 5 symbols can be regarded as a single PUSCH having 10 symbols in the first nominal repetition. Therefore, the DMRS OFDM symbol positions of the single PUSCH having 10 symbols can be configured at the first and ninth symbols (1603). For the second nominal repetition of a single actual repetition having 9 symbols, the DMRS can be transmitted as is in the first and seventh OFDM symbols. This can enable the PUSCH to be transmitted at a lower channel coding rate with no significant difference in channel estimation performance from the existing transmission of 6 DMRS OFDM symbols.

[0164] Figure 17 is a flowchart showing a method of operating a UE according to an embodiment of the present disclosure.

[0165] In operation 1701, the UE can receive, from the BS, repetition transmission configuration information for PUSCH retransmission.

[0166] In one embodiment, the repetition transmission configuration information may include information on the number of repetitions of the PUSCH retransmission and information on the time resources for retransmitting the PUSCH. The information on the time resources for retransmitting the PUSCH may include time resource allocation information for the PUSCH. The time resource allocation information for the PUSCH may include the position of the start symbol of the PUSCH, the time length of the PUSCH, and information on the PUSCH mapping type. The PUSCH mapping type may include PUSCH mapping type A, B, or a new PUSCH mapping type. The new PUSCH mapping type may be the PUSCH mapping type according to method 1 in embodiment 2. Alternatively, the time resource allocation information for the PUSCH may include configuration information on the DMRS OFDM symbol position of the PUSCH. For example, the time resource allocation information for the PUSCH may include information on the DMRS OFDM symbol position configured according to method 2 in embodiment 2.

[0167] According to an embodiment, information about time resources for repeatedly transmitting a PUSCH may include information about a PUSCH repetition transmission type. The PUSCH repetition transmission type may include a PUSCH repetition transmission type A, a PUSCH repetition transmission type B, etc. When the PUSCH repetition transmission type is set to B, the repetition transmission configuration information may be information about the PUSCH repetition transmission type B, including information about time resources for the PUSCH to be repeatedly transmitted n times based on the number of repetitions, information about invalid symbols, etc. Information about the PUSCH repetition transmission type B has been described in detail previously, and thus its description will not be repeated.

[0168] In one embodiment, the repetition transmission configuration information may be received from the BS via higher layer signaling (e.g., RRC signaling) or L1 signaling (e.g., DCI).

[0169] In operation 1702, the UE may receive hopping configuration information including configuration information about a hopping interval between a plurality of frequency resources for transmitting a PUSCH. Operation 1720 may correspond to Figure 7 operations 701 and 702 of Figure 8 operations 801 and 802 of Figure 9 operations 901 and 902 of

[0170] In one embodiment, the hopping configuration information may include information indicating hopping to be performed for repeated transmission.

[0171] According to an embodiment, the hopping configuration information may include information about a plurality of frequency resources for performing hopping (i.e., two or more frequency resources). Information about the plurality of frequency resources may include information about frequency bands of the plurality of frequencies, information about a frequency interval (or frequency offset) between the plurality of frequency resources, etc. In addition, the hopping configuration information may include information about an order of performing hopping.

[0172] In one embodiment, the hopping configuration information may include configuration information about a hopping interval between a plurality of frequency resources. The configuration information about the hopping interval may correspond to the foregoing interval pattern and include information about a time interval for performing hopping between the plurality of frequency resources.

[0173] In one embodiment, the hopping interval may be configured based on time slots. In such a case, the time-slot-based hopping interval may be configured according to the above method 1-1 in the first embodiment. In another embodiment, the hopping interval may be configured based on the transmission unit of the PUSCH that is configured to be transmitted according to the number of retransmissions. In such a case, the hopping interval may be configured based on the transmission unit of the PUSCH that is configured to be transmitted according to the number of retransmissions according to the above method 1-2 in the first embodiment. In another embodiment, the hopping interval may be configured based on the transmission unit in which the PUSCH is actually and repeatedly transmitted, and the transmission unit is determined according to the information on invalid symbols. In such a case, the hopping interval based on the transmission unit in which the PUSCH is actually and repeatedly transmitted may be configured according to the above method 1-3 in the first embodiment. In another embodiment, the hopping interval may be configured based on the time-division duplex (TDD) UL-DL configuration. In such a case, the hopping interval based on the TDD UL-DL configuration may be configured according to the above method 2.

[0174] In one embodiment, the configuration information of the hopping interval may include information on a reference of the time interval for performing frequency hopping. For example, based on the time interval reference, when the time interval (i.e., symbol length) between two PUSCHs is less than the time interval reference, the UE may not perform frequency hopping, and when the time interval is greater than the time interval reference, frequency hopping is performed. The time interval reference for performing frequency hopping may correspond to the reference for determining consecutive PUSCH transmissions in the above method 3 of the first embodiment.

[0175] In one embodiment, the frequency hopping configuration information may include information on a bitmap to determine the hopping interval. In such a case, the bitmap for determining the hopping interval may be configured according to the above method 4 in the first embodiment.

[0176] In one embodiment, the frequency hopping configuration information may correspond to the number of retransmissions, and the UE may receive the frequency hopping configuration information from the BS in each retransmission. In addition, at operation 1710, the UE may determine the frequency hopping configuration information corresponding to the information on the number of retransmissions received from the BS. Alternatively, the UE may receive a plurality of frequency hopping configuration information from the BS, and may determine the frequency hopping configuration information to be used for frequency hopping among the plurality of frequency hopping configuration information by receiving information indicating one of the plurality of frequency hopping configuration information.

[0177] In one embodiment, the frequency hopping configuration information may be received from the BS through higher layer signaling (e.g., RRC signaling) or L1 signaling (e.g., DCI).

[0178] At operation 1703, when performing frequency hopping at a hopping interval based on the retransmission configuration information and the frequency hopping configuration information, the UE may repeatedly transmit the PUSCH to the BS.

[0179] In one embodiment, the UE may determine the frequency resources and time resources for repeatedly transmitting the PUSCH according to the retransmission configuration information and the frequency hopping configuration information. In addition, the UE may determine the hopping interval for performing frequency hopping according to the frequency hopping configuration information. When performing frequency hopping based on the frequency resources, time resources, and hopping interval for PUSCH retransmission, the UE may repeatedly transmit the PUSCH to the BS.

[0180] In one embodiment, the UE may repeatedly transmit the PUSCH including the DMRS to which the same precoding is applied. The UE may receive the configuration information about applying the same precoding to the DMRS from the BS, and repeatedly transmit the PUSCH by applying the same precoding to the DMRS based on this configuration.

[0181] Figure 18 It is a flowchart showing a BS operation method according to an embodiment of the present disclosure. Figure 18 It shows the Figure 17 BS operation method corresponding to the UE operation method of Figure 17 The description of Figure 18 overlapping will not be repeated.

[0182] In operation 1801, the BS may send the retransmission configuration information for PUSCH retransmission to the UE.

[0183] In operation 1802, the BS may send the frequency hopping configuration information to the UE, and the frequency hopping configuration information includes the configuration information about the hopping interval between multiple frequency resources for transmitting the PUSCH.

[0184] In operation 1803, when performing frequency hopping at a hopping interval based on the retransmission configuration information and the frequency hopping configuration information, the BS may repeatedly receive the repeatedly transmitted PUSCH from the UE.

[0185] In operation 1804, the BS may estimate the channel by simultaneously using at least one DMRS included in the repeatedly received PUSCH.

[0186] In one embodiment, the BS may determine the DMRS to be used for performing channel estimation. For example, the BS may determine the PUSCH received in the repeatedly received PUSCH by using the same frequency resource within a specific time interval. The BS may determine the DMRS included in the determined PUSCH as the DMRS to be used for performing channel estimation. The BS may perform channel estimation by simultaneously using the determined DMRS. In such a case, the specific time interval may be determined based on the minimum time interval that allows channel estimation to be performed by simultaneously using multiple DMRSs.

[0187] In one embodiment, the BS may send information configuring the repeated transmission of the PUSCH to the UE by applying the same precoding to the DMRS. The configuration information for precoding may be sent in one of the foregoing operations. The BS may repeatedly receive the PUSCH including the DMRS to which the same precoding has been applied from the UE, and estimate the channel by simultaneously using the DMRS to which the same precoding has been applied.

[0188] Figure 19 is a block diagram of a UE according to an embodiment of the present disclosure.

[0189] Referring to Figure 19 , the UE 1900 may include a transceiver 1910, a controller 1920, and a memory 1930. The transceiver 1910, the controller 1920, and the memory 1930 of the UE 1900 may operate according to the method for effectively transmitting or receiving channels and signals in the 5G communication system as described above in connection with the previous embodiments. However, the elements of the UE 1900 are not limited thereto. For example, the UE 1900 may include more or fewer elements than those described above. In addition, in special cases, the transceiver 1910, the controller 1920, and the memory 1930 may be implemented in the form of a single chip.

[0190] In another embodiment, the transceiver 1910 may include a transmitter and a receiver. The transceiver 1910 may send a signal to the BS or receive a signal from the BS. These signals may include control information and data. To this end, the transceiver 1910 may include an RF transmitter for up-converting the frequency of the signal to be transmitted and amplifying the signal, and an RF receiver for low-noise amplifying the received signal and down-converting the frequency of the received signal. In addition, the transceiver 1910 may receive a signal on the wireless channel and output the signal to the controller 1920, or transmit the signal output from the controller 1920 on the wireless channel.

[0191] The controller 1920 may control a series of processes of the UE 1900 to operate according to embodiments of the present disclosure. For example, according to embodiments of the present disclosure, considering a method of estimating a channel by simultaneously using DMRSs transmitted in multiple PUSCHs, the controller 1920 may perform at least one of a method of changing the OFDM symbol position of the DMRS and a method of performing frequency hopping. To this end, the controller 1920 may include at least one processor. For example, the controller 1920 may include a communication processor (CP) for controlling communication and an application processor (AP) for controlling a high layer such as an application program.

[0192] The memory 1930 may store control information or data included in signals obtained by the UE 1900, such as frequency hopping information, information related to channel estimation using DMRSs transmitted in multiple PUSCHs simultaneously, etc., and has sectors for storing data required for the control of the controller 1920 and data that occurs during the control of the controller 1920.

[0193] Figure 20 is a block diagram of a BS according to one embodiment.

[0194] Referring to Figure 20 , the BS 2000 may include a transceiver 2010, a controller 2020, and a memory 2030. The transceiver 2010, the controller 2020, and the memory 2030 of the BS 2000 may operate according to methods for effectively transmitting or receiving channels and signals in a 5G communication system as described above in connection with previous embodiments. However, the elements of the BS 2000 are not limited thereto. In another embodiment, the BS 2000 may include more or fewer elements than those described above. In addition, in special cases, the transceiver 2010, the controller 2020, and the memory 2030 may be implemented in the form of a single chip.

[0195] In another embodiment, the transceiver 2010 may include a transmitter and a receiver. The transceiver 2010 may transmit signals to the UE or receive signals from the UE. These signals may include control information and data. To this end, the transceiver 2010 may include an RF transmitter for up-converting the frequency of the signal to be transmitted and amplifying the signal, and an RF receiver for low-noise amplifying the received signal and down-converting the frequency of the received signal. In addition, the transceiver 2010 may receive signals on a wireless channel and output the signals to the controller 2020, or transmit signals output from the controller 2020 on a wireless channel.

[0196] The controller 2020 may control a series of processes of the BS 2000 to operate according to embodiments of the present disclosure. For example, according to embodiments of the present disclosure, considering a method of estimating a channel by simultaneously using DMRSs transmitted in a plurality of PUSCHs, the controller 2020 may perform at least one of a method of changing the OFDM symbol position of the DMRS and a method of performing frequency hopping. To this end, the controller 2020 may include at least one processor. For example, the controller 2020 may include a CP for controlling communication and an AP for controlling a higher layer such as an application program.

[0197] The storage 2030 may store control information or data determined by the BS 2000, such as frequency hopping information, information related to channel estimation using DMRSs transmitted in a plurality of PUSCHs simultaneously, etc., and control information or data received from the UE, and has sectors for storing data required for the control of the controller 2020 and data occurring during the control of the controller 2020.

[0198] Several embodiments of the present disclosure have been described, but those of ordinary skill in the art will understand and appreciate that various modifications can be made without departing from the scope of the present disclosure. Therefore, it will be apparent to those of ordinary skill in the art that the present disclosure is not limited to the described embodiments of the present disclosure, which are provided for illustrative purposes only. In addition, if necessary, the embodiments may be operated by combining with each other.

Claims

1. A method for repeatedly transmitting a Physical Uplink Shared Channel (PUSCH) performed by a User Equipment (UE), the method comprises: receiving hopping interval information from a base station via higher layer signaling, wherein a first number of time slots in a first frequency hop for hopping and a second number of time slots in a second frequency hop for hopping are identified by the hopping interval information; receiving hopping information from the base station via Downlink Control Information (DCI), wherein the hopping information includes information indicating that hopping is to be performed for the PUSCH; and performing repeated hopping for the PUSCH based on the hopping interval information and the hopping information, wherein performing repeated hopping for the PUSCH includes: repeatedly transmitting the PUSCH in the first frequency hop based on the first number of time slots identified by the hopping interval information, and repeatedly transmitting the PUSCH in the second frequency hop based on the second number of time slots identified by the hopping interval information.

2. The method according to claim 1, further comprises: receiving, via the DCI, information indicating the number of repeated transmissions of the PUSCH and time resource allocation information of the PUSCH.

3. The method according to claim 2, wherein the time resource allocation information of the PUSCH includes information about a start symbol of the PUSCH, information about a time length of the PUSCH, and information about a mapping type of the PUSCH.

4. The method according to claim 1, wherein the higher layer signaling includes Radio Resource Control (RRC) signaling.

5. A method for repeatedly receiving a Physical Uplink Shared Channel (PUSCH) performed by a base station, the method comprises: sending hopping interval information to a User Equipment (UE) via higher layer signaling, wherein a first number of time slots in a first frequency hop for hopping and a second number of time slots in a second frequency hop for hopping are identified by the hopping interval information; sending hopping information to the UE via Downlink Control Information (DCI), wherein the hopping information includes information indicating that hopping is to be performed for the PUSCH; and performing repeated hopping for the PUSCH based on the hopping interval information and the hopping information, wherein performing repeated hopping for the PUSCH includes: repeatedly receiving the PUSCH in the first frequency hop based on the first number of time slots identified by the hopping interval information, and repeatedly receiving the PUSCH in the second frequency hop based on the second number of time slots identified by the hopping interval information.

6. The method according to claim 5, further comprises: sending, via the DCI, information indicating the number of repeated transmissions of the PUSCH and time resource allocation information of the PUSCH.

7. The method according to claim 6, wherein the time resource allocation information of the PUSCH includes information about a start symbol of the PUSCH, information about a time length of the PUSCH, and information about a mapping type of the PUSCH.

8. The method according to claim 5, wherein the higher layer signaling includes Radio Resource Control (RRC) signaling.

9. A User Equipment (UE) for repeatedly transmitting a Physical Uplink Shared Channel (PUSCH), the UE comprises: a transceiver; and At least one processor, coupled to a transceiver, wherein the at least one processor is configured to: Receive hopping interval information from a base station via high-layer signaling, wherein a first number of time slots in a first frequency hop for frequency hopping and a second number of time slots in a second frequency hop for frequency hopping are identified by the hopping interval information; Receive hopping information from the base station via downlink control information DCI, wherein the hopping information includes information indicating that frequency hopping is to be performed for a PUSCH; and Perform repeated frequency hopping for the PUSCH based on the hopping interval information and the hopping information, wherein performing repeated frequency hopping for the PUSCH includes: Repeatedly transmit the PUSCH in the first frequency hop based on the first number of time slots identified by the hopping interval information, and Repeatedly transmit the PUSCH in the second frequency hop based on the second number of time slots identified by the hopping interval information.

10. A base station for repeatedly receiving a physical uplink shared channel PUSCH, the base station comprising: A transceiver; and At least one processor, coupled to the transceiver, wherein the at least one processor is configured to: Send hopping interval information to a user equipment UE via high-layer signaling, wherein a first number of time slots in a first frequency hop for frequency hopping and a second number of time slots in a second frequency hop for frequency hopping are identified by the hopping interval information; Send hopping information to the UE via downlink control information DCI, wherein the hopping information includes information indicating that frequency hopping is to be performed for a PUSCH; and Perform repeated frequency hopping for the PUSCH based on the hopping interval information and the hopping information, wherein performing repeated frequency hopping for the PUSCH includes: Repeatedly receive the PUSCH in the first frequency hop based on the first number of time slots identified by the hopping interval information, and Repeatedly receive the PUSCH in the second frequency hop based on the second number of time slots identified by the hopping interval information.

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