Patent Description:
In order to meet wireless data traffic demands that have increased after <NUM> communication system commercialization, efforts to develop an improved <NUM> communication system or a pre-<NUM> communication system have been made. For this reason, the <NUM> communication system or the pre-<NUM> communication system is called a beyond <NUM> network communication system or a post LTE system. In order to achieve a high data transmission rate, an implementation of the <NUM> communication system in a mmWave band (for example, <NUM> band) is being considered. In the <NUM> communication system, technologies such as beamforming, massive MIMO, Full Dimensional MIMO (FD-MIMO), array antenna, analog beam-forming, and large scale antenna are being discussed as means to mitigate a propagation path loss in the mm Wave band and increase a propagation transmission distance. Further, the <NUM> communication system has developed technologies such as an evolved small cell, an advanced small cell, a cloud Radio Access Network (RAN), an ultra-dense network, Device to Device communication (D2D), a wireless backhaul, a moving network, cooperative communication, Coordinated Multi-Points (CoMP), and received interference cancellation to improve the system network. In addition, the <NUM> system has developed Advanced Coding Modulation (ACM) schemes such as Hybrid FSK and QAM Modulation (FQAM) and Sliding Window Superposition Coding (SWSC), and advanced access technologies such as Filter Bank Multi Carrier (FBMC), Non Orthogonal Multiple Access (NOMA), and Sparse Code Multiple Access (SCMA).

Meanwhile, the Internet has been evolved to an Internet of Things (IoT) network in which distributed components such as objects exchange and process information from a human-oriented connection network in which humans generate and consume information. An Internet of Everything (IoE) technology in which a big data processing technology through a connection with a cloud server or the like is combined with the IoT technology has emerged. In order to implement IoT, technical factors such as a sensing technique, wired/wireless communication, network infrastructure, service-interface technology, and security technology are required, and research on technologies such as a sensor network, Machine-to-Machine (M2M) communication, Machine-Type Communication (MTC), and the like for connection between objects has recently been conducted. In an IoT environment, through collection and analysis of data generated in connected objects, an intelligent Internet Technology (IT) service to create a new value for peoples' lives may be provided. The IoT may be applied to fields, such as a smart home, smart building, smart city, smart car, connected car, smart grid, health care, smart home appliance, or high-tech medical service, through the convergence of the conventional Information Technology (IT) and various industries.

Accordingly, various attempts to apply the <NUM> communication to the IoT network are made. For example, the <NUM> communication technology, such as a sensor network, machine-to-machine (M2M) communication, and machine-type communication (MTC), has been implemented by a technique, such as beamforming, MIMO, and array antennas. The application of a cloud RAN as the big data processing technology may be an example of convergence of the <NUM> technology and the IoT technology.

In general, mobile communication systems have been developed for the purpose of providing communication while securing users' mobility. Intense development of technologies has enabled mobile communication systems to evolve to such an extent that, not only voice communication, high-speed data communication services can also be provided. There has recently been ongoing standardization of a new radio (NR) system in the <NUM>rd generation partnership project (3GPP), which is one of next-generation mobile communication systems. The NR system has been developed to satisfy various network requirements and to accomplish a wide range of performance targets, and this technology is particularly aimed at implementing communication in millimeter-wave bands. Hereinafter, the NR system may be understood as encompassing <NUM> NR systems supporting microwaves including communication in millimeter-wave bands of <NUM> GH or higher, <NUM> LTE systems, and LTE-A systems.

The relevant prior art consists in the following documents: <CIT> and <CIT>.

In a millimeter-wave (mmWave) band of <NUM> or higher in which the NR system can be supported, signals need to be transmitted by using a large amount of power, in order to compensate for the high degree of path loss between a base station and a terminal, as well as signal attenuation. In this case, it is difficult to employ any multi-carrier transmission technology. Accordingly, the disclosure proposes a method and an apparatus for effectively transmitting/receiving signals by using a single carrier in a mmWave band.

According to an embodiment, a base station may simultaneously support one or more terminals by using a single carrier with a high frequency efficiency. Moreover, the base station may dynamically adjust the CP, thereby improving the data transmission efficiency.

In describing the exemplary embodiments of the disclosure, descriptions related to technical contents which are well-known in the art to which the disclosure pertains, and are not directly associated with the disclosure, will be omitted. This omission of the unnecessary description is intended to prevent the main idea of the disclosure from being unclear and more clearly transfer the main idea.

Further, the size of each element does not entirely reflect the actual size.

The advantages and features of the disclosure and methods of achieving the same will be apparent by referring to embodiments of the disclosure as described below in detail in conjunction with the accompanying drawings. However, the disclosure is not limited to the embodiments described below, and may be implement in various different forms. The embodiments are provided only to make the disclosure complete and to help a person skilled in the art to which the disclosure pertains fully understand the scope of the disclosure. The disclosure is to be defined only by the scope of the claims.

And each block of the flowchart illustrations may represent a module, segment, or portion of code, which includes one or more executable instructions for implementing the specified logical function(s).

As used herein, the "unit" refers to a software element or a hardware element, such as a Field Programmable Gate Array (FPGA) or an Application Specific Integrated Circuit (ASIC), which performs a predetermined function. However, the "unit" does not always have a meaning limited to software or hardware. However, the "unit does not always have a meaning limited to software or hardware. The "unit" may be constructed either to be stored in an addressable storage medium or to execute one or more processors. Therefore, the "unit" includes, for example, software elements, object-oriented software elements, class elements or task elements, processes, functions, properties, procedures, sub-routines, segments of a program code, drivers, firmware, micro-codes, circuits, data, database, data structures, tables, arrays, and parameters. The elements and functions provided by the "unit" may be either combined into a smaller number of elements, "unit" or divided into a larger number of elements, "unit". Moreover, the elements and "units" may be implemented to reproduce one or more CPUs within a device or a security multimedia card. In addition, "<IMG> unit" may include one or more processors in embodiments.

An embodiment is for the purpose of a communication system configured to transmit a downlink signal from a base station to a terminal in an NR system, for example. A downlink signal of the NR includes a data channel through which data information is transmitted, a control channel through which control information is transmitted, and a reference signal (RS) for channel measurement and channel feedback.

Specifically, an NR base station may transmit data and control information to a terminal through a physical downlink shared channel (PDSCH) and a physical downlink control channel (PDCCH), respectively. The NR base station may have multiple RSs, and the multiple RSs may include at least one of a channel state information RS (CSI-RS) and a demodulation reference signal (DMRS) or a terminal-dedicated reference signal. The NR base station transmits the DMRS only in an area scheduled for data transmission, and transmits the CIS-RS by using time and frequency axis resources in order to acquire channel information for data transmission. Hereinafter, data channel transmission/reception may be understood as data transmission/reception through a data channel, and control channel transmission/ reception may be understood as control information transmission/reception through a control channel.

The communication between a base station and a terminal in a wireless communication system is heavily affected by the radio-wave environment. Particularly, in the <NUM> band, severe signal attenuation occurs due to moisture and oxygen in the atmosphere, and a small scattering effect resulting form small wavelengths severely interferes with signal delivery. Accordingly, base stations can secure the coverage only if signals are transmitted using a larger amount of power. If signals are transmitted using a large amount of transmission power, the multi-carrier transmission technology, which can overcome the multi-path delivery effect with an excellent performance, cannot be employed because of the high peak to average power ratio (PAPR). However, performing single-carrier transmission to use a larger amount of transmission power has a problem in that user multiplexing is difficult, and channel estimation and multi-path signal channel estimation performance degrades. In addition, an analog beam (hereinafter, interchangeably referred to as a beam, and may be understood herein as a signal having directivity) is used in the case of a millimeter wave to overcome the severe path loss. The bandwidth of the analog beam is reduced in line with the very short wavelength of the millimeter wave, and this makes multi-user support more difficult. Consequently, it is difficult to guarantee a system performance in the millimeter-wave band at a technical level comparable to that in the micro-wave band.

Accordingly, the disclosure proposes a method and an apparatus for effectively supporting user multiplexing by using a single carrier in a mmWave band, and the method and apparatus will be described with regard to a scenario wherein a base station operates a single carrier, in particular.

The NR system has been developed to satisfy various network requirements, and services supported in the NR system may be classified into the following categories: enhanced mobile broadband (eMBB), massive machine type communications (mMTC), ultra-reliable and low-latency communications (URLLC), and the like. The eMBB is a service aimed at high-speed transmission of a large amount of data, the mMTC is a service aimed at minimizing power consumed by terminals and accessing multiple terminals, and the URLLC is a service aimed at high reliability and low latency. Different requirements may be applied depending on the type of service applied to the terminal.

<FIG> illustrates a diagram of the structure of a time-frequency domain, which is an NR system resource area.

In <FIG>, the horizontal axis refers to a time domain, and the vertical axis refers to a frequency domain. The basic unit of resources in the time and frequency domains is a resource element (RE) <NUM>, which may be defined in terms of one orthogonal frequency division multiplexing (OFDM) symbol <NUM> along the time axis and one subcarrier <NUM> along the frequency axis. In the frequency domain, NSCRB (for example, twelve) continuous REs may constitute one resource block (RB) or physical resource block (PRB) <NUM>.

<FIG> illustrates a diagram of a slot structure considered in an NR system.

<FIG> illustrates exemplary structures of a frame <NUM>, a subframe <NUM>, and a slot <NUM>. One frame <NUM> may be defined as <NUM>. One subframe <NUM> may be defined as <NUM>. Accordingly, one frame <NUM> may include a total of ten subframe <NUM>. One slot <NUM> or <NUM> may be defined as <NUM> OFDM symbols (that is, the number of symbols per slot Nsymbslot is <NUM>). One subframe <NUM> may include one or multiple slots <NUM> or <NUM>. The number of slots <NUM> or <NUM> per subframe <NUM> may vary depending on the configuration value µ <NUM> or <NUM> regarding the subcarrier spacing. <FIG> illustrates exemplary cases in which the subcarrier spacing configuration value is µ =<NUM><NUM> and µ =<NUM><NUM>, respectively. In the case of µ =<NUM><NUM>, one subframe <NUM> may include one slot <NUM>, and in the case of µ =<NUM><NUM>, one subframe <NUM> may include two slots <NUM>. That is, the number Nslotsublrame,µ of slots per subframe may vary depending on the subcarrier spacing configuration value µ, and the number Nslotframe,µ of slots per frame may vary accordingly. Nslotsubframe,µ and Nslotframe,µ may be defined, according to each subcarrier spacing configuration µ, as in Table <NUM> below:.

<FIG> illustrates a diagram of a communication system configured to transmit/ receive data between a base station and a terminal.

Referring to <FIG>, the transmitter is a system capable of OFDM transmission, and may transmit a single carrier (SC) in a bandwidth in which OFDM transmission is possible. The transmitter <NUM> may include a serial-to-parallel (S-P) converter <NUM>, a single-carrier precoder <NUM>, an inverse fast Fourier transform unit <NUM>, a parallel-to-serial (P-S) converter <NUM>, a cyclic prefix (CP) inserter <NUM>, an analog signal unit <NUM> (which may include a digital-to-analog convertor (DAC) and an RF), and an antenna module <NUM>.

Data <NUM> having a size of M (data sequence having a vector size of M) that has undergone channel coding and modulation is converted to a parallel signal by the S-P converter <NUM>, and is then converted to a SC waveform (SCW) by the SC precoder <NUM>. The device <NUM> for converting a parallel signal to an SCW may be implemented in various methods, such as a method of using a discrete Fourier transform (DFT) precoder, a method of using up-converting, a method of using code-spreading, and the like. The disclosure may include various precoding methods. Although the disclosure will be described with reference to an SCW generating method using an DFT precoder, for convenience of description, embodiments are equally applicable to other cases in which the SCW is generated by other methods.

The size of the DFT is equal to M. A data signal that has passed through a DFT precoder (or DFT filter) having a length of M is converted to a wideband frequency signal through the N-point IFFT unit <NUM>. The N-point IFFT processor is configured to transmit parallel signals through respective subcarriers of a channel bandwidth divided into N subcarriers. However, in the case of <FIG>, DFT precoding with length M has been performed before N-point IFT processing. Accordingly, a signal that has undergone DFT precoding is transmitted through a single carrier with reference to a center carrier of a bandwidth to which a signal that has undergone DFT precoding with length M is mapped. The signal (data) that has undergone N-point IFFT processing undergoes a process of the P-S processor <NUM> and is stored as N samples. Some samples in the rear part of the stored N samples are copied and adjoined to the front part. This process is performed by the CP inserter <NUM>.

Thereafter, the signal undergoes a pulse-shaping filter, such as a raised cosine filter, and is delivered to the analog signal unit <NUM>, in which the signal undergoes a digital-to-analog conversion process (through a power amplifier (PA) or the like) and thus is converted to an analog signal. The converted analog signal is delivered to the antenna module <NUM> and thereby radiated into the atmosphere.

In general, an SCW signal is transmitted in such a manner that M precoded signals are mapped to M desired continuous subcarriers and then transmitted, and this process may occur in the IFFT unit <NUM>. Accordingly, the size of M is determined according to the size of transmitted data or the amount of time symbols used by the transmitted data. In general, the size of M is substantially smaller than N, because SCWs are signals characterized by having a small peak-to-average ratio (PAPR).

The PAPR refers to the magnitude of a change in the transmission power of a sample of a transmitted signal. A large PAPR means a large dynamic range of the PA of the transmitter. This means that a large power margin is necessary to operate the PA. In this case, the transmitter configures a high margin of the PA available in case the change will be large. As a result, the maximum power that the transmitter can use decreases, thereby reducing the maximum possible communication distance between the transmitter and the receiver. On the other hand, in the case of an SCW having a small PAPR, the change in the PA is very small. Accordingly, the PA can be operated even if the margin is configured to be small, and the maximum communication distance thus increases.

Since radio-wave attenuation is severe in the case of a mmWave wireless communication system, it is important to secure the communication distance. Accordingly, it is advantageous for the base station to employ a technology that increases the maximum communication distance, such as the SCW. In general, the SCW has a smaller PAPR than a multi-carrier waveform (MCW), and thus has a large margin of <NUM>-6dB. Accordingly, an SCW transmitter can use maximum transmission power larger than that of an MCW transmitter, and the communication distance can thus increase. Such an SCW as in <FIG> is normally used for a terminal having a small upper limit of maximum transmission power, as in the case of the uplink, and has been employed for uplink transmission of an LTE system, in particular. Particularly, terminals do not have a large upper limit of maximum transmission power, and the uplink transmission power is insufficient. Accordingly, it is impossible to configure a large M size, and M decreases as transmission power lacks. Consequently, the transmission distance can be guaranteed by reducing M.

In addition, in the case of the uplink, signals transmitted by one terminal is received by the base station. Accordingly, there is no need to consider a case in which more than one terminals transmit signals by using a single carrier. On the other hand, in the case of a mmWave wireless system, power shortage occurs in the downlink as well due to radio-wave attenuation. In the case of the downlink, the base station inevitably transmits signals for more than one terminals, and this needs to be supported.

<FIG> illustrates a diagram of an exemplary method for transmitting a downlink SCW proposed in the disclosure. The SCW transmission proposed in the disclosure refers to a method wherein a base station transmits data to one or more terminals through the same SCW, and the base station transmits signals by using a single SCW for one symbol. However, a terminal that receives signals may receive one or more SCWs through the same symbol.

A terminal may receive at least one piece of configuration information regarding which time-frequency resource is transmitted by using a single SCW, and this may be delivered through system information by means of high-layer signaling. As used herein, high-layer signaling includes system information transmitted through a physical broadcast channel and/or a signal that delivers system information, such as a system information block (SIB) and/or a radio resource control (RRC) signal. The configuration information includes information regarding a time resource to which SCW transmission is applied (for example, the index and period of a slot) and frequency resource information (for example, the index of a continuous frequency resource or a resource block (RB) corresponding thereto, or the start index and end index of the RB, or the start and length of the RB, or information delivering identical information thereto). In addition, the configuration information includes: information regarding time/frequency synchronization through a reference signal, such as a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a DMRS, which needs to be referred to in order to receive the corresponding resource; base station information (base station ID); channel parameter information such as delay spread and average delay power; beam information (beam index); or interworking information such as a synchronization signal block (SSB) index. The interworking information refers to information determining the value of various parameters necessary for the receiver to receive a SCW signal. In addition, the system information may include at least one of the size of a bandwidth used for SCW transmission, or the size (M) of the DFT, or the size of the bandwidth and the index of a subcarrier, through which the center frequency is transmitted, or the size of the bandwidth, and the index of a subcarrier corresponding to the end of the bandwidth.

Referring to <FIG>, data stream #<NUM> and data stream #<NUM><NUM> and <NUM>, which are data signals transmitted to different terminals, respectively, undergo channel coding and modulation, undergo S-P conversion, and pass through the M-point DFT <NUM> (SCW precoder). The size of the data vector of data stream #<NUM> and data stream #<NUM> has a total length of M. Thereafter, M samples go through the N-point IFFT <NUM> and undergo P-S conversion <NUM>. A CP is added thereto (<NUM>), and the M samples then undergo digital-to-analog conversion <NUM> such that they are converted to analog signals, which are delivered to the antenna module <NUM>. In the case of a mmWave wireless system, an analog beam is used to additionally compensate for path loss. Using a beam means that a signal that has undergone analog conversion is subjected to space-utilizing post-processing (post-coding) (not a process of space-utilizing pre-processing of data streams #<NUM> and #<NUM><NUM> and <NUM> which are digital signals for beam formation, in general). Accordingly, a separate circuit <NUM> (which may be an FPGA) is necessary to operate the same, and this circuit plays the role of adjusting the coefficient of each antenna element (AE) such that signals are delivered in a desired direction.

The technology proposed in the disclosure relates to a case in which a single base station transmits signals by using a single SCW, regardless of the number of terminals to which the base station transmits signals. The method for multiplexing between terminals is as illustrated in <FIG>.

<FIG> illustrates a diagram of a method for multiplexing one or more terminals to one symbol and transmitting the same in an SCW system to which an embodiment is applied. The disclosure proposes a method wherein different samples are selected from M samples that are necessary before SC precoding, and then transmitted. According to <FIG>, the FFT size <NUM> along the frequency axis may correspond to N in <FIG> and <FIG>, and the DFT size <NUM> (corresponding to the size of the bandwidth of the SCW) may correspond to M in <FIG> and <FIG>. The sample of terminal <NUM> may correspond to the sub-symbol part (SSP) <NUM>, and the sample used by terminal <NUM> may correspond to the SSP <NUM>. In the proposed method as illustrated in <FIG>, the total amount <NUM> and <NUM> of samples used by one or more terminals may be equal to or smaller than M.

If two terminals are multiplexed to M samples, for example, respective terminals may receive information of the size N <NUM> of the entire FFT from the base station, or may implicitly recognize the same, and may receive information of the size <NUM> of the bandwidth of the SCW through system information. If the size <NUM> is M, the potential resource <NUM> used by terminal <NUM> may be transmitted from the base station to the terminal through high-layer signaling as information regarding the position of continuous resources among M resources, or the starting and ending points of the resource, or the starting point and the length of the resource. The potential resource <NUM> used by terminal <NUM> may also be transmitted from the base station to the terminal through high-layer signaling as information regarding the position of continuous resources among M resources, or the starting and ending points of the resource, or the starting point and the length of the resource. Such resource information may be delivered as a bitmap, or in a decimally converted form, or as a table-based indication, or by using a material pre-recorded in a memory, or by using information configured through a reconfigurable memory. For example, if the SCW bandwidth size (or M) is indicated as a multiple of <NUM> subcarriers, the relation may be configured as in Table <NUM> below:.

Table <NUM> above enumerates sets of SCW bandwidth sizes, which are multiples of <NUM>, among numbers configured by multiplying respective elements in the columns of <NUM>, <NUM>, and <NUM>, which have fast SC precoding calculation speeds, among available SCW bandwidth sizes. Each item may be transmitted to the terminal through high-layer signal as a bitmap or an integer indicating the number of RBs. If the SCW bandwidth size is indicated by the number of RBs as a multiple of <NUM>, the SCW table may be configured in as in Table <NUM> below:.

Table <NUM> above enumerates sets of SCW bandwidth sizes, which have the number of RBs corresponding to a multiple of <NUM>, and which have fast SC precoding speeds, among available SCW bandwidth sizes. Each item may be transmitted through high-layer signal as a bitmap or a constant (which may be an integer) indicating a group of RBs.

The resources <NUM> and <NUM> used by terminals <NUM> and <NUM> may be configured to be orthogonal to each other or to overlap each other. Since a resource transmitted through high-layer signaling is a potential resource (that is, resource that may be used for signal transmission), the transmission resource of the data channel actually transmitted may be a part of the potential resource <NUM> configured for terminal <NUM>, and may be a part of the potential resource <NUM> configured for terminal <NUM>. In order to support both terminals <NUM> and <NUM> in the same symbol, the positions of the actually transmitted data channels need to be configured to be orthogonal (that is, not to overlap) even if the potential resources may overlap. The resource of such an actually transmitted data channel may be indicated to each terminal through a control channel such as a physical downlink control channel (PDCCH).

If respective data channels are transmitted without overlapping, and if samples of a symbol <NUM> transmitted along the time axis are enumerated successively, data <NUM> mapped at a location having a small index on the frequency axis is transmitted first (<NUM>) on the time axis, and data <NUM> transmitted thereafter is then transmitted (<NUM>) on the time axis.

In addition, according to an embodiment proposed in the disclosure, discontinuous potential resources can be assigned to respective terminals. If the DFT size <NUM> is M, the discontinuous potential resource <NUM> used by terminal <NUM> may be indicated through high-layer signaling including information regarding the position of the discontinuous resource among the resource of M, or the starting point and interval of the discontinuous resource, or the starting point of the discontinuous resource, the length of a continuous resource, and the interval of the continuous resource. The discontinuous potential resource <NUM> used by terminal <NUM> may be indicated through high-layer signaling including information regarding the position of the discontinuous resource among the resource of M, or the starting point and interval of the discontinuous resource, or the starting point of the discontinuous resource, the length of a continuous resource, and the interval of the continuous resource. Such resource information may be delivered as a bitmap, or as a table-based indication, or by using a material pre-recorded in a memory, or by using information configured through a reconfigurable memory. The size of the discontinuous resource may be indicated by at least one unit selected from a sample, a subcarrier, one or more continuous subcarriers, an RB, and one or more continuous RBs. Resources <NUM> and <NUM> used by terminals <NUM> and <NUM> may be configured as resources which are orthogonal to each other or which overlap each other.

Since a resource transmitted through high-layer signaling is a potential resource, the transmission resource of the data channel actually transmitted may be a part of the potential resource <NUM> configured for terminal <NUM>, and may be a part of the potential resource <NUM> configured for terminal <NUM>. In order to support both terminals <NUM> and <NUM> in the same symbol, the positions of the actually transmitted data channels need to be configured to be orthogonal (that is, not to overlap) even if the potential resources may overlap. The resource of such an actually transmitted data channel may be indicated to each terminal through a control channel such as a PDCCH. If respective data channels are transmitted without overlapping, symbol samples transmitted to terminals <NUM> and <NUM> are transmitted while being enumerated in a temporally discontinuous and successive manner as indicated by <NUM> and <NUM>. The method proposed in the disclosure can transmit data for one or more terminals through a single symbol, although a SCW is used, and this is possible by temporally dividing the symbol.

Accordingly, the concept of "bandwidth part (BWP)" used in NR systems is no longer valid, and according to the disclosure, sub-symbol parts (SSPs) <NUM>, <NUM>, <NUM>, and <NUM> corresponding to parts of a time symbol are used. Through the SSPs, the base station can freely multiplex data through time division duplexing of the symbol, and time division duplexing between data channels, between a DMRS and data, between a DMRS and a PDCCH, between a DMRS, a PDCCH, and a PDCSCH, or between a PDCCH and a PDSCH is possible within one symbol. In addition, according to SSP resource assignment, samples constituting each symbol may be classified into samples that are used and samples that are not used. There is an advantage in that, by differently configuring such a resource configuration between users or between base stations, interference can be reduced.

The following is a description of the configuration of a radio resource control (RRC) information element according to an embodiment to which the disclosure is applied. According to an embodiment, a BWP information element or SSP information element may include at least one constituent element in Table <NUM> below:.

In Table <NUM> above, "locationAndBandwidth" refers to the position of the starting point of the BWP and the bandwidth thereof, and "subcarrierSpacing" refers to the subcarrier spacing applied to the BWP. "Interleaved" indicates that the PRB for signal transmission inside the BWP is assigned discontinuously, and through "sampled-BundleSize", "interleaverSize", and "ShiftIndex", the interleaver input unit for discontinuous assignment, the interleaving unit, and the BWP-specific offset are indicated, respectively, "nonInterleaved" indicates that no interleaver is used. That is, a PRB for signal transmission inside the BWP is assigned continuously. "TransmissionComb" indicates that BWP resource assignment proceeds in a comb type. "combGroup" refers to a comb unit (subcarrier) and means that, unless "combGroup" is configured (or indicated), the unit is <NUM> (n1). That is, the same indicates that the comb may be configured with regard to each subcarrier. "combOffset" denotes the comb of the actually used resource among resources distinguished by "combGroup". For example, if "combGroup" is configured as <NUM>, a different comb is configured for every two subcarriers. It can be understood that, if the comb number is <NUM>, and if "combOffset" is <NUM>, <NUM>th, <NUM>st, <NUM>th, <NUM>th, <NUM>th, and <NUM>th subcarrier are assigned.

Although it has been described that the information of Table <NUM> above is included in the BWP information element, the same may be included in an SSP information element. Alternatively, at least one piece of the above information may be included in a master information block (MIB), an SIB, or cell-common RRC information, such as BWP-DownlinkCommon, besides the BWP information element.

<FIG> illustrates a diagram of a method for determining the size of M, which is the size of DFT (or size of SCW bandwidth) according to the disclosure. The base station may consider the following issues in connection with determining the size of M. The SCW precoding device is an addition to an existing OFDM system, and thus requires an additional processing operation compared with the existing OFDM system, and the time necessary therefor needs to be minimized. To this end, in the case of an M-point DFT processor, the processing time can be shortened by using a specific M value only. A DFT processor having M configured as a product of exponentiations of <NUM>, <NUM>, and <NUM> is widely used because the precoding time can be substantially reduced through special hardware.

Referring to <FIG>, reference numeral <NUM> denotes an assigned channel bandwidth, reference numeral <NUM> denotes a maximum assignable physical RB in view of characteristics of the transmitting filter (or spectrum mask) <NUM>, and this may be understood as the maximum available resource. The maximum PRB <NUM> is given in such a manner that a partial frequency area of the channel bandwidth <NUM> is not used. If the bandwidth <NUM> actually used for SCW transmission is not identical to the size of the maximum available PRB <NUM>, and if the size of M is configured to be smaller than reference numeral <NUM> in view of the size of the maximum available PRB <NUM>, some resources <NUM> positioned at both ends of the maximum SCW size (or maximum DFT window) <NUM> cannot be used for data channel transmission. This causes a problem in that the maximum supportable transmission rate is lower than that of the existing NR system. In general, the frequency efficiency of the existing NR system is about <NUM>-<NUM>%, but the frequency efficiency is reduced to <NUM>-<NUM>% (by <NUM>-<NUM>%) if the SCW is used. Table <NUM> below enumerates the number of RBs <NUM> according to the subcarrier spacing (SCS) available in a mmWave band and the channel bandwidth (BW) (MHz):.

The number <NUM> of actually available subcarriers, based thereon, is given in Table <NUM> below:.

The SCW bandwidth <NUM> can be converted to the number of subcarriers based on Table <NUM> above, and the result is given in Table <NUM> below. Table <NUM> enumerates values configured as products of exponentiation of <NUM>, <NUM>, and <NUM>, which are largest among numbers equal to or smaller than the number of actually usable subcarriers in Table <NUM>, with regard to each channel bandwidth and subcarrier spacing. SC precoding can be conducted quickly by using a value in Table <NUM> as the SCW bandwidth (or DFT size).

Table <NUM> below enumerates frequency efficiencies calculated based on Table <NUM> above:.

It is clear from Table <NUM> above that the frequency efficiency is about <NUM>%, and drops to <NUM>% or less in the case of some combinations of subcarrier spacings and channel bandwidths.

In order to solve this, the disclosure proposes a technology regarding a method wherein the SCW bandwidth <NUM> (which may be interpreted as the maximum DTF window, DFT size, or the like) is configured to be larger than the maximum available PRB <NUM> from products of exponentiations of <NUM>, <NUM>, and <NUM>. According to the conventional method, the SCW bandwidth <NUM> is configured to be largest among products of respective exponentiations of <NUM>, <NUM>, and <NUM>, but to be smaller than the maximum available PRB <NUM>, but use of the proposed method can maintain the frequency efficiency at about <NUM>%. However, this method has a problem in that the SCW uses a bandwidth larger than the bandwidth allowed by the transmitting filter <NUM>, and this can be solved by using the following six methods:.

According to the first method, the channel bandwidth uses a wider frequency band pass filter, and the band cutoff slope of the filter is maintained to be larger. This method makes it possible to use a wider bandwidth while maintaining the same channel bandwidth configuration as in the existing method. According to the second method, the interval between channel bandwidths is slightly increased, and a guard band is additionally configured between channel bandwidths. This method makes it possible to configure an SCW bandwidth without changing the frequency band filter. According to the third method, a different SCW bandwidth is configured for each time symbol. For example, the data channel has an SCW bandwidth configured to be smaller than the channel bandwidth, and the SCW band of the symbol used to transmit an DMRS is configured to be larger than the channel bandwidth. If a DMRS is transmitted in this case, there is little channel estimation performance degradation because, even if the band filter distorts signals on both ends of the SCW band, the DMRS is transmitted through a wideband.

According to the fourth method, the SCW bandwidth is dynamically changed for each symbol. <FIG> illustrates a diagram of a fourth method for solving a problem occurring if an SCW uses a bandwidth larger than a bandwidth allowed by a transmitting filter. According to the fourth method, if the bandwidth <NUM> necessary for the currently transmitted symbol corresponds to a part of the entire channel bandwidth <NUM> (that is, if a PRB in a partial band is scheduled), the M size <NUM> is configured with reference to the scheduled PRB, not the channel bandwidth <NUM>.

According to the fifth method, the SCW bandwidth is dynamically changed for each symbol, but is changed only within a limited SCW bandwidth configuration. <FIG> is a diagram illustrating a fifth method for solving a problem occurring if an SCW uses a bandwidth larger than a bandwidth allowed by a transmitting filter. According to <FIG>, information <NUM> of one or more SSPs or BWPs is configured for the terminal, and the size of the SCW bandwidth <NUM> is configured as the smallest value larger than the BWP or SSP size. The SSP or BWP for data transmission may be determined according to information of the PDCCH that schedules the data transmission resource, and the bandwidth of the used SCW size may change according to the SSP or BWP for data transmission.

To this end, the base station needs to indicate the relation between bandwidths occupied by the SSP, BWP, and SCW to the terminal through high-layer signaling by adding the same to SSP or BWP frequency band information. As a method therefor, the base station may transmit at least one piece of information regarding whether the bandwidths of the SCW and the SSP coincide at the starting point or at the ending point, or whether of not an offset <NUM> (difference value between the stating points of the bandwidths of the SCW and the SSP) occurs, to the base station together with SCW bandwidth information. The offset may be indicated by the number of subcarriers, and this may be implicitly indicated based on the absolute position of the subcarriers (the number within N), or the distance between point A <NUM> (or point <NUM> or the lowest index of channel bandwidth or the lowest index of BWP) and the stating point of the SCW, or the definition that point A and the SCW have the same start. As used herein, point A refers to a point serving as a reference to indicate the PRB.

According to the sixth method, N and M are configured to have the same size. <FIG> illustrates a diagram of a sixth method for solving a problem occurring if an SCW uses a bandwidth larger than a bandwidth allowed by a transmitting filter. Referring to <FIG>, the size of N may be determined by the size of the channel bandwidth or the transmission bandwidth, and M may be configured to have the same size as N. That is, the SCW bandwidth <NUM> is identical to the channel bandwidth <NUM>, and the existing wideband filter <NUM> may be used accordingly. In this case, the operation of the M-DFT and N-IFFT have the same effect as up-converting a data vector to a given bandwidth. This proposed method has an advantage in that, since the hardware structure is simple, a device in the existing OFDM modem can be used without modification, and there is no error between the channel bandwidth and the SCW bandwidth. <FIG> illustrates a diagram of another exemplary method for performing the sixth method for solving a problem occurring if an SCW uses a bandwidth larger than a bandwidth allowed by a transmitting filter. According to <FIG>, such a structure in which the SCW bandwidth and the channel bandwidth are identical may also be confirmed in the N-point DFT <NUM> and the N-point IFFT <NUM>.

In order to support this, the guard band needs to be configured differently from the existing method. The guard band is configured in the existing system such that, among N divided bandwidths, continuous frequency areas on both ends are not used. However, the proposed method uses all available bands to transmit N subcarriers, and the guard band needs to be separately configured between the channel band and an adjacent channel band. In addition, since the proposed method divides the channel bandwidth used by the base station to N subcarriers, the SCS corresponds to the BW divided into N parts. That is, the SCS may be defined by Equation <NUM> below, wherein f(a) is a function returning a value which is smaller than or equal to a, and which is configured as a product of exponentiations of <NUM>, <NUM>, and <NUM>:<MAT>.

For example, if the above-described second method is used, the SCW bandwidth based on a combination of a SCS and a channel bandwidth may be converted to the number of subcarriers as given in Table <NUM> below:.

The maximum number of available RBs can be calculated based on Table <NUM>, and the result is given below:.

Frequency efficiencies calculated based on Table <NUM> are given in Table <NUM> below:.

It is clear from Table <NUM> above that, compared with Table <NUM>, all frequency efficiencies have improved to <NUM>% or higher.

For example, if the proposed fifth method is used, the number of available subcarriers, based on a combination of a SCS and a channel bandwidth, is given in Table <NUM> below:.

Available SCW bandwidths may be converted to SCW bandwidths, which are expressed as products of exponentiations of <NUM>, <NUM>, and <NUM>, based on the number of available subcarriers given in Table <NUM>, and the result is given in Table <NUM> below:.

Frequency efficiencies calculated based on Table <NUM> above are given below:.

It can be confirmed from Table <NUM> that, if the fifth method is used, the frequency efficiencies are improved about to <NUM>%, which corresponds to the existing level of LTE or NR.

<FIG> illustrates a diagram of an exemplary method for transmitting a DMRS and data by using a method proposed in the disclosure, <FIG> illustrates a diagram of an exemplary method for transmitting a DMRS and data by using a method proposed in the disclosure, and <FIG> illustrates a diagram of an exemplary method for transmitting a DMRS and data by using a method proposed in the disclosure. In order to use the proposed technology to transmit a DMRS and a PDSCH, it is necessary to transmit the DMRS first and then to transmit the PDSCH (time division transmission). A method for transmitting a DMRS and data if there occurs an offset between the SCW bandwidth and the SSP or BWP bandwidth, for example, will now be described.

Referring to <FIG>, if the SCW bandwidth <NUM> (DFT size) is configured to be larger than the bandwidth of the actual data channel or SSP or the bandwidth <NUM> of the BWP, as in <NUM>, the DMRS <NUM> is transmitted by determining the length of an RS sequence used for the DMRS through a resource occupied on a virtual frequency axis according to the SCW bandwidth size, and data <NUM> is assigned to a bandwidth smaller than the bandwidth for transmitting the DMRS. It can be confirmed from a comparison between <NUM> and <NUM> that the offsets of the two bandwidths are evenly divided at both ends of the bandwidths. If the offset is arranged at the end of one bandwidth as in <NUM> in <FIG>, frequency bands may be arranged as in <NUM> and <NUM>.

Arranging offsets at both ends of bandwidths and arranging the same at the start or end of a bandwidth, as described above, may affect the channel estimation performance. If offsets exist on at both ends, the start and end of a DMRS sample may be distorted, thereby degrading the overall channel estimation performance. If an offset is arranged at the end of a bandwidth (that is, if the offset is arranged in a high frequency band such that the SCW bandwidth and the SSP bandwidth have the same starting points), the first DMRS sample is not affected. Accordingly, performance degradation is not severe as long as channel delay spread is small. However, distortion of the last DRMS sample may generate an error in the latter half of the DMRS sample if the channel is actually estimated, and the latter half part of the estimated spread may be arbitrarily removed in this case, so as to reduce the channel estimation error. If the offset is arranged at the start of a bandwidth (that is, if the offset is arranged in a low frequency band such that the SCW bandwidth and the SSP bandwidth have the same ending points), the channel estimation error occurring in the initial part affects the channel estimation of the overall bandwidth. The error range is larger in this case than when channel estimation errors exist at both ends, thereby having the largest influence on performance degradation. Accordingly, if three methods are all possible, the channel estimation performance may be improved further by arranging the offset such that the sample on the last part is distorted (that is, on the side with the higher frequency).

If M=N are configured as in <NUM> in <FIG>, bandwidths may be configured identically as in <NUM> and <NUM>. However, in the case of N, exponentiations of <NUM> can only be supported for fast processing, and in the case of M, exponentiations of <NUM>, <NUM>, and <NUM> are solely possible. This has a problem in that the actual subcarrier spacing differs from those of other examples (because N is changed if M is changed), and the subcarrier spacing needs to be changed dynamically according to the used scheduling bandwidth. This is because an accurate clock is difficult to generate in the case of a millimeter wave, for which a super-high frequency is used, and noise occurs due to inaccurate clock occurrence. A noise removing operation is necessary to prevent noise-induced performance degradation. If the subcarrier spacing is small, the noise removal performance degrades, and a sufficient time to change the subcarrier spacing needs to be secured to maintain modem synchronization. Accordingly, this method may be used in the case of a modem or an operating scenario, which does not require fast processing, may be difficult to use if fast processing is necessary as in the case of URLLC. In order to prevent this problem, the speed may be improved by predetermining an available candidate from subcarrier spacing candidates. Such a group of subcarrier spacing candidates may be delivered through an SIB or system information.

Table <NUM> below is a description of RRC information elements for supporting the proposed disclosure.

Although the RRC information elements in Table <NUM> above are described as being included in a BWP information element, at least one of such information elements may be included in a different information element, such as SSP. In Table <NUM> above, "locationAndBandwidth" refers to the position of the starting point of the BWP and the bandwidth, and "subcarrierSpacing" refers to the subcarrier spacing applied to the BWP. "SingleCarrier" indicates whether or not a single carrier is transmitted in the BWP, "DFTSize" indicates the position of the starting point of the DFT bandwidth and the bandwidth, and "DFToffset" refers to the above-mentioned offset.

The above-mentioned information may be expressed in another method, and the technology proposed in the disclosure is identically applicable to such a case as well. For example, "DFTSize INTEGER (<NUM>. <NUM>)" may also be expressed as follows: DFTSize SEQUENCE {n2 INTERGER (<NUM>. <NUM>), n3 INTERGER (<NUM>. <NUM>), n5 INTERGER (<NUM>. Through these expressions, the DFT size may be indicated as a product of exponentiations of <NUM>, <NUM>, and <NUM>.

<FIG> illustrates a diagram of an exemplary method for dynamically adjusting a CP when using single-carrier transmission proposed in the disclosure, <FIG> illustrates a diagram of an exemplary method for dynamically adjusting a CP when using single-carrier transmission proposed in the disclosure, FIG. 8BC illustrates a diagram of an exemplary method for dynamically adjusting a CP when using single-carrier transmission proposed in the disclosure, and FIG. 8BD illustrates a diagram of an exemplary method for dynamically adjusting a CP when using single-carrier transmission proposed in the disclosure. Referring to <FIG>, if the downlink bandwidth (or channel bandwidth) operated by the base station is like <NUM> in the case of <NUM>, the base station selectively uses the frequency to transmit signals to a terminal. This is because the terminal supports a bandwidth smaller than the system bandwidth, or signal transmission using a smaller bandwidth is more efficient to improve the system performance, depending on the scheduling condition. In this case, the base station modulates data transmitted to the terminal, and assigns the same to an assigned bandwidth <NUM>. In order to transmit data through a single carrier, data is transmitted through single-carrier precoding with the same size as the assigned bandwidth.

Since signals are received by the terminal through multiple paths, a CP is added to the signal <NUM> and then transmitted, as in <NUM>. In <FIG>, the horizontal axis denotes the time resource (symbol), and the vertical axis denotes the frequency resource. As a CP adding method, last N samples of the transmission signal are copied to transmit the signal. Using this method is advantageous in that a continuous transmission signal can be maintained and delivered seamlessly, and the receiver can reconstruct the signal even if the accurate starting point of the reception signal may not be recognized. In spite of this advantage, transmission power and time used for CP transmission are unavailable for data transmission, thereby degrading the system performance, and a degradation of about <NUM>% generally occurs.

However, in the case of a millimeter-wave band, multi-path loss is very severe, and substantially no delay occurs due to the multi-path. In addition, the number of antennas increases in connection with beamforming, which is applied to compensate for path loss, and the beam width substantially decreases. Such a decreases further decreases delay, and substantially no spreading occurs due to the multi-path, or spreading can be predicted based on the beamforming used by the base station. For example, if a wide beam is used through beamforming, path angle spread increases, but a decrease in the transmission signal intensity is predictable. If a narrow beam is used through beamforming, it can be predicted that the angle of the transmission signal path will not spread, and substantially no time spread will occur. If a fixed CP is used in this case as in the existing method, the system performance undergoes a severe loss. A variable CP may be used to prevent such a system performance loss, and a method for supporting a variable CP will be proposed below.

Referring to <FIG>, reference numeral <NUM> in <NUM> corresponds to a method for supporting a variable CP through a resource assignment method. The method proposed in the disclosure is for the purpose of securing an additional CP in a symbol having a CP configured through a minimum time spread (not a CP configured with reference to maximum time spread as in the prior art), or securing a CP in a symbol having no CP. A method proposed to this end follows the two following rules. According to the first rule, if a transmitted symbol needs a CP, a continuous RE resource having a low frequency resource index, within a resource assignment area given by a resource assignment method, is used as zero or is maintained. According to the second rule, if an RE resource having the highest frequency resource index within a resource assignment area given in the previous symbol is not used, a continuous RE resource having a low index may be used in the next symbol. If the second rule cannot be followed, the first rule is to be followed. A resource having zero assigned thereto (or empty resource) on the frequency axis is empty on the time axis during SCW transmission, and thus can be used as a guard between symbols, like a CP.

Reference numeral <NUM> corresponds to a case in which the first rule is followed, and it can be confirmed that the RE resource having a low frequency resource index, which is assigned to the first symbol, is empty. Reference numeral <NUM> corresponds to a case in which no frequency resource <NUM> having a high index has been assigned in the previous first symbol, and an RE resource <NUM> having a low frequency resource index is available in the next second symbol (accordingly, the second rule is followed). In the case of <NUM>, a frequency resource having a high frequency resource index has been used in the previous second symbol, like <NUM>, and the second rule cannot be used accordingly. Instead, a RE resource having a low frequency resource index is emptied according to the first rule. This rule follows a virtual PR-physical RB mapping (VRP-to-PRB mapping) rule, and the rule of VRB may be expressed as in Table <NUM> below:.

<FIG> illustrates a diagram of another exemplary method for dynamically adjusting the length of a CP, and <FIG> illustrates a diagram of another exemplary method for dynamically adjusting the length of a CP. According to the method corresponding to <NUM> in <FIG>, a fixed CP is applied to a symbol for transmitting a DMRS, and a variable CP is applied to a symbol for transmitting data. If this method is used, a channel estimation technique based on multiple paths may be applied through the DMRS, and in the case of a data channel, the terminal may use information obtained from the DRMS for channel estimation. To this end, the base station needs to have at least one piece of information given in Table <NUM> below included in DMRS transmission configuration information within the BWP.

wherein "dmrs-Type" is an indicator indicating the type of the transmitted DMRS; "dmrs-AdditionalPosition" is an indicator indicating the position of an additional DMRS; "Dmrs-CPlength" indicates the length of the CP used for DMRS reception; and "len x" indicates that the CP length corresponds to <NUM>/x of the symbol length. If "dmrs-CPlength" is not configured, the CP length is indicated as zero. "maxLength" indicates the maximum symbol number of the DMRS. "scramblingID0" and "<NUM>" indicate initialization values of DMRS sequence generation. "phaseTrackingRS" is an indicator indicating a PTRS configuration if PTRS exists.

In addition, for the purpose of PDSCH transmission, the base station needs to have at least one piece of information given in Table <NUM> below included in PDSCH configuration information:.

wherein "dmrs-DownlinkForPDSCH-MappingTypeC" refers to the method for transmitting a DMRS and a PDSCH, to which the proposed variable CP is applied.

According to the method corresponding to <NUM> in <FIG>, a new DMRS is transmitted so as to support a variable CP. This method is for the purpose of improving the performance of the data symbol at <NUM> in <FIG>. In the case of the prior art, signal processing is completed before the IFFT unit, and transmission then occurs. Accordingly, signal processing of the DMRS is also completed before the IFFT. In this case, the DMRS is configured to be transmitted in a specific frequency band. However, if a single carrier is used, it is difficult to transmit the DMRS through a part symbol because DMRS signal processing is performed before the DFT processor. Therefore, DMRS transmissions such as <NUM>, <NUM>, <NUM>, and <NUM> are possible after the IFFT unit. In the case of <NUM> in <FIG>, the second symbol <NUM> and the third symbol <NUM> are continuously transmitted on the time axis, and the terminal may accordingly conduct channel estimation by determining that <NUM> and <NUM> are DMRSs.

<FIG> illustrates a diagram of an example of generating a zero-power sample in connection with single-carrier transmission proposed in the disclosure. Referring to <FIG>, in the above-mentioned process of assigning a resource by using a data stream transmitted to a terminal, a method of transmitting a zero-power or null signal in the case of some samples is applied to the transmitting end, as in <NUM>. However, in this case, some modems may undergo abnormal power signal generation, and the following four methods are proposed to prevent this.

<FIG> illustrates a diagram of a method for preventing generation of a zero-power sample in connection with single-carrier transmission proposed in the disclosure, <FIG> illustrates a diagram of a method for preventing generation of a zero-power sample in connection with single-carrier transmission proposed in the disclosure, <FIG> illustrates a diagram of a method for preventing generation of a zero-power sample in connection with single-carrier transmission proposed in the disclosure, and <FIG> illustrates a diagram of a method for preventing generation of a zero-power sample in connection with single-carrier transmission proposed in the disclosure. The first method <NUM> illustrated in <FIG> uses a zero-power sample for retransmission. That is, a data stream transmitted to the terminal is repeatedly input to the DFT processor, thereby transmitting signals, such that the zero-power sample does not occur. Such repetition may be conducted by a repeating or virtual copying unit <NUM>. The first method is also referred to as a method for performing retransmission inside a symbol. The method for retransmission inside a symbol means that, if the length of a data channel transmitted regardless of a data reception confirmation response (ACK or NACK) from the receiver is smaller than the symbol, data is repeated and retransmitted according to the length of the corresponding symbol. The terminal may obtain channel coding gain through the retransmitted symbol, through symbol reception.

According to the second method <NUM> illustrated in <FIG>, an additional RS is transmitted. If the length of a transmission data stream is insufficient compared with the bandwidth, an additional RS may be transmitted without transmitting additional data (<NUM>). The RS transmitted in this case may be for purpose of predicting phase noise and compensating for the same, instead of channel estimation. If a millimeter-wave band is used, severe noise occurs in the terminal's element and in the terminal device, and an RS is necessary for alleviating the same. In addition, the corresponding resource is used to transmit the RS, in order to prevent the zero-power sample.

According to the third method <NUM> illustrated in <FIG>, time spreading is applied to a data stream to be transmitted. Single-carrier transmission is identical to frequency spreading, in terms of the effect. If the length of a data symbol vector for data transmission is smaller than the number of actually transmittable symbols, additional spreading may be applied to the data symbol such that time-axis spreading occurs. In this case, the data symbol is transmitted through frequency spreading through single-carrier transmission, and additional time band spreading, thereby increasing the reliability and the coverage. According to the fourth method <NUM> illustrated in <FIG>, a symbol filter is used. The symbol filter refers to a pulse-shaping filter applied after a data signal is generated, and is used to convert a digital signal to an analog signal. If a signal passes through a filter, the length thereof increases in proportion to the number of taps of the filter. This makes it possible to design a zero-power sample so as to generate a filter output close to zero, although not exactly zero. To put in another manner, the number of zero-power samples may be reduced by increasing the number of taps of the filter such that the zero-tail increases.

<FIG> illustrates a diagram of an exemplary method wherein one or more base stations using single-carrier transmission proposed in the disclosure supports a single terminal by using a continuous virtual resource.

Referring to <FIG>, for the purpose of the method proposed below, each base station (or transmission and reception unit (TxRP or TRP)) does not necessarily have the same channel bandwidth used for the corresponding bandwidth, but needs to have the same position as that of the bandwidth of the single carrier. Such bandwidth information needs to be agreed and/or exchanged in advance between the base stations. The channel bandwidth used by RxRP <NUM> is <NUM>, and the bandwidth of the single carrier (or DFT size) is <NUM>. In addition, the channel bandwidth used by TxRP <NUM> is <NUM>, and the bandwidth of the single carrier is <NUM>. In this case, <NUM> and <NUM> are not necessarily identical, but the positions and bandwidths of <NUM> and <NUM> need to be identical.

In addition, one or more base stations or TxRPs using the bandwidth of the same single carrier need to user continuous resources that do not overlap each other within the single carrier band, and such resource information needs to be agreed and/or exchanged in advance. If TxRP <NUM> uses a resource such as <NUM> as the SPS, if TxRP <NUM> uses a resource such as <NUM> as the SSP, and if resources used by respective base stations in the above example do not overlap, one or more base stations may transmit different data channels to one terminal, and the terminal may receive data channels transmitted from two different TxRPs at different timepoints on the time axis, such as <NUM> (corresponding to data transmitted from TxRP <NUM>) and <NUM> (corresponding to data transmitted form TxRP <NUM>), within one symbol. That is, data transmitted by different base stations may under TDM within the symbol.

<FIG> illustrates a diagram of an exemplary method wherein one or more base stations using single-carrier transmission proposed in the disclosure supports a single terminal by using a discontinuous virtual resource.

Referring to <FIG>, for the purpose of the method proposed below, each base station (or transmission and reception unit (TxRP or TRP)) does not necessarily have the same channel bandwidth used for the corresponding bandwidth, but needs to have the same position as that of the bandwidth of the single carrier. Such bandwidth information needs to be agreed and/or exchanged in advance between the base stations. The channel bandwidth used by TxRP <NUM> is <NUM>, and the bandwidth of the single carrier (or DFT size) is <NUM>. In addition, the channel bandwidth used by TxRP <NUM> is <NUM>, and the bandwidth of the single carrier is <NUM>. In this case, <NUM> and <NUM> are not necessarily identical, but the positions and bandwidths of <NUM> and <NUM> need to be identical.

In addition, one or more base stations or TxRPs using the bandwidth of the same single carrier need to user discontinuous resources that do not overlap each other within the single carrier band, and such resource information needs to be agreed and/or exchanged in advance by respective base stations. If TxRP <NUM> uses a resource such as <NUM> as the SSP, if TxRP <NUM> uses a resource such as <NUM> as the SSP, and if resources used by respective base stations thus do not overlap, one or more base stations may transmit different data channels to one terminal, and the terminal may simultaneously receive data channels from two different TxRPs at different timepoints on the time axis, as in the case of <NUM>, within one symbol.

To this end, in order to exchange information for using discontinuous resources between base stations, at least one piece of information given in Table <NUM> below may be exchanged between the base stations:.

<FIG> illustrates a diagram of operations of a base station transmitting a data channel according to the disclosure. Referring to <FIG>, in step <NUM>, the base station determines the bandwidth of a single carrier according to the size of a system bandwidth and that a configured sub-system bandwidth. The system bandwidth may correspond to a channel bandwidth, and the sub-system bandwidth may correspond to a resource that can be assigned to a terminal. That is, the sub-system bandwidth may correspond to a BWP or SSP, and may correspond to a resource that can be assigned for multiple terminals. The bandwidth of the single carrier may correspond to a DFT size, and this may be determined by the above-mentioned method. In step <NUM>, the base station confirms the difference between the bandwidth of the single carrier and the system bandwidth or the configured sub-system bandwidth. In step <NUM>, the base station assigns a continuous or discontinuous time resource to multiple terminals before single-carrier filtering (which may be interpreted as SC precoding, single carrier conversion, or DFT precoding). A resource assigned to one terminal may be continuous or discontinuous. In step <NUM>, the terminal performs single-carrier filtering so as to convert the data signal of multiple terminals by the single carrier, performs IFFT, analog signal conversion, and the like, and transmits the data signal to the multiple terminals (step <NUM>). Not all steps of the operations in <FIG> are necessarily performed, and may also be performed in a changed order.

<FIG> illustrates a diagram of a base station transmitting data by using a single carrier. In step <NUM>, the base station confirms single-carrier transmission configuration information in order to perform single-carrier transmission through a transceiver supporting orthogonal frequency division multiplexing (FDM) transmission. Such configuration information may include a time-frequency resource to which single-carrier transmission is applicable, a set of available DFT sizes, and the like. In addition, such information may be transmitted to a terminal through high-layer signaling such as system information. In step <NUM>, the base station determines the bandwidth of a reference signal transmitted through the bandwidth of the single carrier and the size of the bandwidth of the data channel, and performs data mapping with the reference signal. In addition, in step <NUM>, the base station may confirm the position and size of a symbol through which a CP is transmitted. The base station may map a data symbol to a time symbol through which no CP is transmitted, and then transmit the same. The base station may map a reference signal to a symbol through which a CP is transmitted, and then transmit the same. Alternatively, the CP may be assigned to each symbol as described in the disclosure. Such CP configuration-related information may be transmitted through high-layer signaling such as system information. Such CP related operations may be omitted.

In step <NUM>, the base station may generate a signal to be transmitted to a time sample that generates no transmission power (zero-power sample). This step may be omitted, and the base station generates and maps a sample to replace the zero-power sample in the above-mentioned method. In step <NUM>, the base station performs single-carrier precoding with regard to the mapped data and the reference signal, performs IFFT, analog signal conversion, and the like, and transmits a signal to the terminal.

<FIG> illustrates a diagram of a terminal receiving signals by using a single carrier. In step <NUM>, the terminal receives a symbol(s) transmitted by the base station through a transceiver supporting orthogonal frequency division multiplexing (OFDM) transmission. The received signal is converted to a frequency signal through FFT in step <NUM>. In step <NUM>, the terminal reconstructs the channel by using the received DMRS. In step <NUM>, the terminal compensates for the channel for each subcarrier by using the reconstructed channel information. In step <NUM>, the terminal performs an IDFT operation by using an already-received single carrier information (frequency position, DFT length). In strep <NUM>, the terminal demultiplexes the data symbol by using already-received resource assignment information, stores the same, reconstructs the same, thereby acquiring the signal transmitted by the base station.

<FIG> illustrates a diagram of operations of at least one base station supporting a single terminal by using the same single-carrier bandwidth. According to <FIG>, TxRP <NUM><NUM> and TxRP <NUM><NUM> are base stations capable of supporting transmission to one terminal by using the same single-carrier bandwidth. TxRP <NUM><NUM> and TxRP <NUM><NUM> may exchange information regarding a bandwidth and information regarding resources that respective base stations will assign to transmit data within the single-carrier band (step <NUM>). Through this process, respective base stations may determine the same single-carrier band to use, and may assign resources for data transmission so as not to overlap. In step <NUM>, TxRP <NUM><NUM> transmits single-carrier transmission configuration information to the terminal <NUM>. The single-carrier transmission configuration information may include at least one of the above-mentioned RRC IEs. Then, TxRP <NUM><NUM> may transmit a PDCCH that indicates a resource to transmit data to the terminal <NUM>. Then, TxRP <NUM><NUM> may transmit a PDSCH (or data channel) to the terminal <NUM> by using the resource. In this case, data transmitted by TxRP <NUM><NUM> and data transmitted by TxRP <NUM><NUM> may be transmitted in respective SSPs within the symbol on the time axis. The terminal <NUM> may receive data transmitted by respective base stations at different timepoints on the time axis.

<FIG> illustrates a diagram of a base station device according to the disclosure. The base station device <NUM> may include a transceiver <NUM>, a controller <NUM>, and a memory <NUM>. The transceiver <NUM> may exchange signals with a terminal. The signals may include control information, a reference signal, and data. To this end, the transceiver <NUM> may include an RF transmitter configured to up-convert and amplify the frequency of a transmitted signal, an RF receiver configured to low-noise-amplify a received signal and to down-convert the frequency thereof, and the like. In addition, the transceiver may receive a signal through a radio channel, may output the same to the controller <NUM>, and may transmit a signal output from the controller <NUM> through the radio channel. The controller <NUM> may control a series of processes such that the base station can operate according to an embodiment.

<FIG> illustrates a diagram of a terminal device according to the disclosure. The terminal device <NUM> may include a transceiver <NUM>, a controller <NUM>, and a memory <NUM>. The transceiver <NUM> may exchange signals with a terminal. The signals may include control information, a reference signal, and data. To this end, the transceiver <NUM> may include an RF transmitter configured to up-convert and amplify the frequency of a transmitted signal, an RF receiver configured to low-noise-amplify a received signal and to down-convert the frequency thereof, and the like. In addition, the transceiver may receive a signal through a radio channel, may output the same to the controller <NUM>, and may transmit a signal output from the controller <NUM> through the radio channel. The controller <NUM> may control a series of processes such that the terminal can operate according to embodiments described above.

Claim 1:
A method performed by a base station in a wireless communication system, the method comprising:
identifying configuration information for the single carrier-based signal transmission;
transmitting, to two or more terminals, the configuration information; and
transmitting, to the two or more terminals, a downlink signal on a symbol for a single carrier waveform according to the configuration information,
wherein the symbol for the single carrier waveform is divided into two or more sub-symbol parts and the two or more sub-symbol parts are associated with the two or more terminals, respectively, and
wherein the configuration information includes information regarding resources to which the single carrier-based signal transmission is applied.