WO2022270823A1 - 다중 대역 채널 추정을 통한 가시 경로 채널을 활용하는 방법 및 장치 - Google Patents
다중 대역 채널 추정을 통한 가시 경로 채널을 활용하는 방법 및 장치 Download PDFInfo
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Definitions
- the present disclosure provides radio propagation through transmission and processing of channel frequency response and channel impulse response signals estimated by multi-band channel measurement in a wireless communication system.
- LOS line-of-sight
- the maximum transmission speed is tera (i.e., 1,000 gigabytes) bps
- the wireless delay time is 100 microseconds ( ⁇ sec). That is, the transmission speed in the 6G communication system compared to the 5G communication system is 50 times faster and the wireless delay time is reduced to 1/10.
- 6G communication systems use terahertz bands (such as the 95 GHz to 3 terahertz (3 THz) bands).
- terahertz bands such as the 95 GHz to 3 terahertz (3 THz) bands.
- An implementation in is being considered.
- the terahertz band it is expected that the importance of technology that can guarantee signal reach, that is, coverage, will increase due to more serious path loss and atmospheric absorption compared to the mmWave band introduced in 5G.
- radio frequency (RF) devices As the main technologies for ensuring coverage, radio frequency (RF) devices, antennas, new waveforms that are superior in terms of coverage than orthogonal frequency division multiplexing (OFDM), beamforming, and massive multiple- Multi-antenna transmission technologies such as input and multiple-output (massive MIMO), full dimensional MIMO (FD-MIMO), array antenna, and large scale antenna must be developed.
- new technologies such as metamaterial-based lenses and antennas, high-dimensional spatial multiplexing technology using orbital angular momentum (OAM), and reconfigurable intelligent surface (RIS) are being discussed to improve coverage of terahertz band signals.
- full duplex technology in which uplink and downlink simultaneously utilize the same frequency resource at the same time, satellite and Network technology that integrates HAPS (high-altitude platform stations), network structure innovation technology that supports mobile base stations and enables network operation optimization and automation, dynamic frequency sharing through collision avoidance based on spectrum usage prediction (dynamic spectrum sharing) technology, AI (artificial intelligence) from the design stage, AI-based communication technology that realizes system optimization by internalizing end-to-end AI support functions, Development of next-generation distributed computing technology that realizes high-complexity services by utilizing ultra-high-performance communication and computing resources (mobile edge computing (MEC), cloud, etc.) is underway.
- MEC mobile edge computing
- the 6G communication system is expected to provide services such as truly immersive extended reality (truly immersive XR), high-fidelity mobile hologram, and digital replica.
- services such as remote surgery, industrial automation, and emergency response through security and reliability enhancement are provided through the 6G communication system, which can be applied in various fields such as industry, medical care, automobiles, and home appliances. It will be.
- An object of the present disclosure is to determine the presence or absence of a visible path of a radio propagation channel by measuring a multi-band channel in a wireless communication system, and to provide a wireless transmission/reception operation utilizing characteristics of a visible path channel when a visible path channel exists.
- a method for a base station to identify a visual path channel in a wireless communication system comprising: receiving a signal for measuring a channel in each of multiple bands from a terminal; based on the signal, determining whether the channel is a line-of-sight channel for each of the multiple bands; in response to determining that the visible path channel exists in each of the multiple bands, identifying the channel as the visible path channel; and transmitting data to the terminal based on the visual path channel.
- a method for identifying a visible path channel in a wireless communication system comprising: receiving a signal for measuring a channel in each of multiple bands from a base station; based on the signal, determining whether the channel is a line-of-sight channel for each of the multiple bands; in response to determining that the visible path channel exists in each of the multiple bands, identifying the channel as the visible path channel; and transmitting data to the base station based on the visible path channel.
- the base station includes: a transceiver; and a processor.
- the processor controls the transceiver to receive a signal for measuring a channel in each of the multi-bands from a terminal, and based on the signal, the channel is a line-of-sight path for each of the multi-bands. channel, and in response to determining that the visible path channel exists in each of the multi-bands, identify the channel as the visible path channel, and transmit data to the terminal based on the visible path channel. It may be configured to control the transceiver.
- FIG. 1 is a diagram showing the basic structure of a time-frequency domain, which is a radio resource domain in which data or control channels are transmitted in LTE and LTE-A systems.
- PDCCH 201 which is a downlink physical channel through which downlink control information (DCI) of LTE is transmitted.
- DCI downlink control information
- 3 is a diagram showing an example of basic units of time and frequency resources constituting a downlink control channel that can be used in 5G or 6G.
- CORESET control resource set
- 5 is a diagram showing an example of configuration for a downlink resource block structure in 5G.
- FIG. 6 is a diagram illustrating an internal structure of a base station or terminal for identifying visible path channels in a wireless communication system according to an embodiment of the present disclosure.
- FIG. 7 is a flowchart of a method for a base station to identify visible path channels in a wireless communication system according to an embodiment of the present disclosure.
- FIG. 8 is a flowchart of a method for a terminal to identify visible path channels in a wireless communication system according to an embodiment of the present disclosure.
- FIG. 9 is a flowchart of an operation for estimating a visible path channel according to an embodiment of the present disclosure.
- FIGS. 10A and 10B are diagrams illustrating an example of estimating a delay time through transmission and reception of a downlink RACH signal according to an embodiment of the present disclosure.
- 11A and 11B are diagrams illustrating results of measuring received signal strengths of a visible path channel and an invisible path channel according to an embodiment of the present disclosure.
- 12A and 12B are diagrams illustrating path attenuation measurement results of a visible path channel and an invisible path channel according to an embodiment of the present disclosure.
- 13A, 13B, and 13C are diagrams illustrating example power delay distributions and threshold voltages of visible and invisible path channels according to an embodiment of the present disclosure.
- 14a, 14b, 14c, and 14d are diagrams for explaining a method of determining power delay distributions and effective invisible paths of visible and invisible path channels according to an embodiment of the present disclosure.
- 15A, 15B, 15C, and 15D are diagrams for explaining power delay distributions and root mean square delay spread results of visible and invisible path channels according to an embodiment of the present disclosure.
- 16 is a diagram illustrating symbol design in the time domain according to presence or absence of visible path channels according to an embodiment of the present disclosure.
- 17A and 17B are diagrams for explaining a method of reducing reference signal density and increasing multiplexing according to presence or absence of visible path channels according to an embodiment of the present disclosure.
- 18A and 18B are examples illustrating a method of estimating a location of a terminal according to an embodiment of the present disclosure.
- 19 is a data transmission/reception flowchart illustrating a method for identifying a visual path channel based on a random access preamble by a base station according to an embodiment of the present disclosure.
- 20 is a data transmission/reception flowchart illustrating a method for a base station to identify a visible path channel based on a reference signal received from a terminal according to an embodiment of the present disclosure.
- 21 is a data transmission/reception flowchart illustrating a method for identifying a visual path channel based on a reference signal received from a base station by a terminal according to an embodiment of the present disclosure.
- 22 is a block diagram illustrating the structure of a terminal according to an embodiment of the present disclosure.
- FIG. 23 is a block diagram illustrating the structure of a base station according to an embodiment of the present disclosure.
- a method for identifying visible path channels by a base station in a wireless communication system includes receiving, from a terminal, a reference signal for measuring a channel in each of multiple bands; Based on the reference signal, determining whether the channel is a line-of-sight or non-line-of-sight for each of the multi-bands; identifying the channel as the visible path channel when the channel is determined to be a visible path in each of the multi-bands; and transmitting at least one of identification result information on the visible path channel or a signal generated based on a characteristic of the visible path channel to the terminal.
- a method for a terminal to identify a visible path channel includes receiving, from a base station, a reference signal for measuring a channel in each of multiple bands; Based on the reference signal, determining whether the channel is a line-of-sight or non-line-of-sight for each of the multi-bands; identifying the channel as the visible path channel when the channel is determined to be a visible path in each of the multi-bands; and transmitting at least one of location information of the terminal, identification result information on the visible path channel, or a signal generated based on a characteristic of the visible path channel to the base station.
- a base station for identifying visible path channels may be provided.
- the base station includes a transceiver; And a processor, wherein the processor controls the transceiver to receive a reference signal for measuring a channel in each of the multi-bands from a terminal, and based on the reference signal, the channel is visible for each of the multi-bands. It is determined whether it is a line-of-sight or a non-line-of-sight path, and if the channel is determined to be a line-of-sight path in each of the multi-bands, the channel is identified as the line-of-sight channel, and the location of the terminal to the terminal is determined. and controlling the transmission/reception unit to transmit at least one of information, identification result information on the visible path channel, or a signal generated based on a characteristic of the visible path channel.
- each block of the process flow chart diagrams and combinations of the flow chart diagrams can be performed by computer program instructions.
- These computer program instructions may be embodied in a processor of a general purpose computer, special purpose computer, or other programmable data processing equipment, so that the instructions executed by the processor of the computer or other programmable data processing equipment are described in the flowchart block(s). It creates means to perform functions.
- These computer program instructions may also be stored in a computer usable or computer readable memory that can be directed to a computer or other programmable data processing equipment to implement functionality in a particular way, such that the computer usable or computer readable memory
- the instructions stored in are also capable of producing an article of manufacture containing instruction means that perform the functions described in the flowchart block(s).
- the computer program instructions can also be loaded on a computer or other programmable data processing equipment, so that a series of operational steps are performed on the computer or other programmable data processing equipment to create a computer-executed process to generate computer or other programmable data processing equipment. Instructions for performing processing equipment may also provide steps for performing the functions described in the flowchart block(s).
- each block may represent a module, segment, or portion of code that includes one or more executable instructions for executing specified logical function(s). It should also be noted that in some alternative implementations it is possible for the functions mentioned in the blocks to occur out of order. For example, two blocks shown in succession may in fact be executed substantially concurrently, or the blocks may sometimes be executed in reverse order depending on their function.
- ' ⁇ unit' used in this embodiment means software or a hardware component such as FPGA or ASIC, and ' ⁇ unit' performs certain roles.
- ' ⁇ part' is not limited to software or hardware.
- ' ⁇ bu' may be configured to be in an addressable storage medium and may be configured to reproduce one or more processors. Therefore, as an example, ' ⁇ unit' refers to components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, and procedures. , subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables.
- components and ' ⁇ units' may be combined into smaller numbers of components and ' ⁇ units' or further separated into additional components and ' ⁇ units'.
- components and ' ⁇ units' may be implemented to play one or more CPUs in a device or a secure multimedia card.
- ' ⁇ unit' may include one or more processors.
- a base station is a subject that performs resource allocation of a terminal, and is at least one of a Node B, a base station (BS), an eNode B (eNB), a gNode B (gNB), a radio access unit, a base station controller, or a node on a network.
- the 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.
- the embodiments of the present disclosure can be applied to other communication systems having a similar technical background or channel type to the embodiments of the present disclosure described below.
- the embodiments of the present disclosure can be applied to other communication systems through some modification within a range that does not greatly deviate from the scope of the present disclosure based on the judgment of a skilled person with technical knowledge.
- 3GPP 3rd Generation Partnership Project Long Term Evolution
- 5G, NR, LTE or similar system standard 5G, NR, LTE or similar system standard
- present disclosure is not limited by the above terms and names, and may be equally applied to systems conforming to other standards.
- the wireless communication system has moved away from providing voice-oriented services in the early days and, for example, 3GPP's HSPA (High Speed Packet Access), LTE (Long Term Evolution or E-UTRA (Evolved Universal Terrestrial Radio Access)), LTE-A (LTE-Advanced), LTE-Pro, 3GPP2's High Rate Packet Data (HRPD), UMB (Ultra Mobile Broadband), and IEEE's 802.16e. evolving into a communication system.
- HSPA High Speed Packet Access
- LTE-A Long Term Evolution-Advanced
- LTE-Pro Long Term Evolution-Pro
- HRPD High Rate Packet Data
- UMB UserMB
- LTE and LTE-A systems adopt an Orthogonal Frequency Division Multiplexing (OFDM) method in downlink (DL), and SC-FDMA (Single Carrier Frequency Division Multiple Access) method is adopted.
- OFDM Orthogonal Frequency Division Multiplexing
- DL downlink
- SC-FDMA Single Carrier Frequency Division Multiple Access
- Uplink refers to a radio link in which a user equipment (UE or mobile station; MS) transmits data or control signals to a base station (eNodeB or base station)
- eNodeB base station
- the multiple access method as described above distinguishes data or control information of each user by assigning and operating time-frequency resources to carry data or control information for each user so that they do not overlap each other, that is, to establish orthogonality. do.
- FIG. 1 is a diagram showing the basic structure of a time-frequency domain, which is a radio resource domain in which data or control channels are transmitted in LTE and LTE-A systems.
- a horizontal axis may represent a time domain and a vertical axis may represent a frequency domain.
- the minimum transmission unit in the time domain is an OFDM symbol.
- N symb (101) OFDM symbols may be gathered to form one slot (102), and two slots may be gathered to form one subframe (103).
- the length of the slot 102 may be 0.5 ms, and the length of the subframe 103 may be 1.0 ms.
- the radio frame 104 is a time domain unit consisting of 10 subframes 103.
- the minimum transmission unit in the frequency domain is a subcarrier, and the bandwidth of the entire system transmission bandwidth may consist of a total of N BW (105) subcarriers.
- the basic unit of resources in the time-frequency domain is a resource element (106, Resource Element, RE), which can be represented by an OFDM symbol index and a subcarrier index.
- a resource block (107, Resource Block, RB or Physical Resource Block, PRB) may be defined as N symb (101) consecutive OFDM symbols in the time domain and N RB (108) consecutive subcarriers in the frequency domain. Accordingly, one RB 107 may be composed of N symb XN RB REs 106 .
- PDCCH 201 which is a downlink physical channel through which downlink control information (DCI) of LTE is transmitted.
- DCI downlink control information
- PDCCH 201 is time multiplexed with PDSCH 202, which is a data transmission channel, and can be transmitted over the entire system bandwidth.
- the area of the PDCCH 201 is represented by the number of OFDM symbols, and the area of the PDCCH 201 may be indicated to the terminal by a Control Format Indicator (CFI) transmitted through a Physical Control Format Indicator Channel (PCFICH).
- CFI Control Format Indicator
- PCFICH Physical Control Format Indicator Channel
- a cell reference signal (CRS) 203 may be used as a reference signal for decoding the PDCCH 201.
- the CRS 203 is transmitted every subframe over the entire band, and scrambling and resource allocation may vary according to cell ID (Identity). Since the CRS 203 is a reference signal commonly used by all terminals, terminal-specific beamforming cannot be used. Therefore, the multi-antenna transmission technique for the PDCCH of LTE is limited to open-loop transmit diversity.
- the number of ports of the CRS is implicitly known to the UE from decoding of the PBCH (Physical Broadcast Channel).
- Resource allocation of the PDCCH 201 is based on a Control Channel Element (CCE), and one CCE is composed of 9 Resource Element Groups (REGs), that is, a total of 36 Resource Elements (REs).
- CCE Control Channel Element
- REGs Resource Element Groups
- the number of CCEs required for a specific PDCCH 201 may be 1, 2, 4, or 8, which varies depending on the channel coding rate of the DCI message payload. As such, different numbers of CCEs may be used to implement link adaptation of the PDCCH 201.
- the terminal needs to detect a signal without knowing the information about the PDCCH 201.
- a search space representing a set of CCEs is defined for blind decoding.
- the search space is composed of a plurality of sets in the AL (Aggregation Level) of each CCE, which is not explicitly signaled and can be implicitly defined through a function and a subframe number according to the UE identity.
- AL Access Level
- the UE decodes the PDCCH 201 for all possible resource candidates that can be created from CCEs within the set search space, and information declared valid for the corresponding UE through CRC check. to process
- the search space can be classified into a terminal-specific search space and a common search space.
- a certain group of terminals or all terminals can search the common search space of the PDCCH 201 in order to receive cell-common control information such as dynamic scheduling for system information or paging messages.
- cell-common control information such as dynamic scheduling for system information or paging messages.
- SIB System Information Block
- 3 is a diagram showing an example of basic units of time and frequency resources constituting a downlink control channel that can be used in 5G or 6G.
- a REG 303 which is a basic unit of time and frequency resources constituting a control channel, consists of 1 OFDM symbol 301 on the time axis and 12 subcarriers 302 on the frequency axis. It may consist of RB.
- the data channel and the control channel can be time-multiplexed within one subframe. By locating the control channel ahead of the data channel, the user's processing time can be reduced, making it easy to satisfy the latency requirement.
- frequency multiplexing between the control channel and the data channel can be performed more efficiently by setting the frequency axis basic unit of the control channel to 1 RB 302 .
- Control channel regions of various sizes can be set by concatenating the REGs 303 shown in FIG. 3 .
- a basic unit to which a downlink control channel is allocated in 5G or 6G is a CCE 304
- one CCE 304 may include a plurality of REGs 303.
- the REG 303 shown in FIG. 3 as an example, the REG 303 may consist of 12 REs, and if 1 CCE 304 consists of 6 REGs 303, 1 CCE 304 This means that it can be composed of 72 REs.
- the corresponding region When a downlink control region is set, the corresponding region may be composed of a plurality of CCEs 304, and a specific downlink control channel may be arranged and transmitted to one or more CCEs 304 according to an AL in the control region.
- the CCEs 304 in the control area are identified by numbers, and at this time, the numbers may be assigned according to a logical arrangement method.
- DMRS 305 may be transmitted in 3 REs within 1 REG 303.
- the terminal can decode the control information without the base station's precoding application information.
- CORESET control resource set
- control region #1 shows an example in which the control area # 2 (402)) is set.
- the control regions 401 and 402 may be set to a specific subband 403 within the entire system bandwidth 410 on the frequency axis.
- the time axis can be set to one or a plurality of OFDM symbols, and this can be defined as a control region length (Control Resource Set Duration, 404).
- control region #1 (401) is set to a control region length of 2 symbols
- control region #2 (402) is set to a control region length of 1 symbol.
- 5 is a diagram showing an example of configuration for a downlink resource block structure in 5G. 5 shows a case in which a specific UE uses 14 OFDM symbols as one slot (or subframe) in downlink, PDCCH is transmitted in the initial two OFDM symbols, and DMRS is transmitted in the third symbol.
- a specific terminal When a specific terminal receives a schedule for a data channel, that is, a PUSCH or a PDSCH, through the PDCCH, data is transmitted and received along with the DMRS within the scheduled resource region.
- a schedule for a data channel that is, a PUSCH or a PDSCH
- data is transmitted and received along with the DMRS within the scheduled resource region.
- a specific RB in which the PDSCH is scheduled data is arranged and transmitted to REs in which the DMRS is not transmitted in the third symbol and REs from the fourth to the last symbol thereafter.
- the subcarrier spacing ⁇ f represented in FIG. 5 is 15 kHz in case of LTE/LTE-A system, and one of ⁇ 15, 30, 60, 120, 240, 480 ⁇ kHz may be used in case of 5G system.
- the LTE/LTE-A system and the 5G system described above are designed to transmit and receive control channels, reference signals, and data channels based on the OFDM scheme. That is, a data symbol sequence ⁇ a 0 , a 1 , ... , a K-1 ⁇ to be transmitted at each subcarrier position on the frequency axis is converted into a signal on the time axis using Inverse Fourier Transform, and given The system is configured to transmit in time intervals.
- the time axis expression of the OFDM signal is as follows [Equation 1].
- ⁇ f denotes the subcarrier spacing and T denotes the OFDM symbol length and rect(x) is can be defined as
- the OFDM symbol length may also be determined according to [Equation 3]. Accordingly, given the frequency bandwidth (BW) and OFDM symbol length ( T ) to transmit an OFDM signal, the number of subcarriers that can be transmitted is number cannot exceed 1, and therefore, the amount of data that can be transmitted for a given symbol length ( T ) may be determined in proportion to the number of corresponding subcarriers.
- embodiments of the present disclosure will be described in detail with accompanying drawings.
- embodiments of the present disclosure are described using LTE/LTE-A and 5G systems as examples, but embodiments of the present disclosure may be applied to other communication systems having similar technical backgrounds or channel types.
- B5G 5G
- 6G 6th generation mobile communication technology
- the embodiments of the present disclosure can be applied to other communication systems through some modifications within a range that does not greatly deviate from the scope of the present disclosure as determined by those skilled in the art.
- FIG. 6 is a diagram illustrating an internal structure of a base station or terminal for identifying visible path channels in a wireless communication system according to an embodiment of the present disclosure.
- the millimeter wave (mmWave) band in addition to the frequency band of 6 GHz or less used in the existing 4G and 5G communication systems, the millimeter wave (mmWave) band and It is expected to additionally utilize the terahertz (THz) band.
- the mmWave band was defined as a frequency band with a wavelength ranging from 1 mm to 10 mm, ranging from 30 GHz to 300 GHz. do.
- the THz band means a frequency bandwidth in the range of 0.1 THz to 10 THz, but in the wireless communication system, it can mean a frequency band of 0.1 THz to 1 THz, that is, 100 GHz to 1,000 GHz band.
- a relatively low frequency is mainly used as a transmission frequency.
- the free-space path loss (FSPL) increases, so that the coverage of radio waves is reduced. because it is shorter.
- FSPL free-space path loss
- radio wave characteristics such as reflection, diffraction, transmission, and scattering of radio waves deteriorate, resulting in a rapid decrease in received signals. Therefore, although a high transmission rate can be obtained through a wide bandwidth by using a high frequency, careful attention is required in antenna and cell planning because the transmission area is relatively narrow.
- 6G or B5G mobile communication systems it is expected that the existing band below 6 GHz and the mmWave/THz band above 6 GHz will be mixed for stable transmission and reception of radio waves even in radio fading areas.
- a mobile communication system that simultaneously uses the aforementioned band below 6 GHz and the mmWave/THz band above 6 GHz as a transmission frequency can be defined as a multi-band communication system.
- different bands may have different radio propagation channel characteristics.
- various channel information can be obtained, one of which is the presence or absence of a visible path channel. Since the radio propagation characteristics of radio waves are almost similar in the existing single-band system, it is possible to determine whether the channel is a line-of-sight (LOS) or a non-line-of-sight (NLOS). It was impossible to check.
- LOS line-of-sight
- NLOS non-line-of-sight
- the present disclosure proposes an operating method for checking the presence or absence of a visible path of radio waves through multi-band channel measurement, and based on this determination, a transmission/reception method corresponding to a visible path channel, determining whether or not there is a visible path, and estimating the position of the radio wave through this determination.
- a technique A base station and a terminal using multiple bands according to an embodiment of the present disclosure may perform visual path presence/absence measurement using a reference signal previously defined in a communication standard without using additional resources.
- a base station and a terminal for determining the existence of a visible path through a channel frequency response and a channel impulse response in a wireless communication system capable of measuring multi-band channels, and performing a transmission operation in a visible path channel state through this determination An operating method and device may be provided.
- a base station or terminal may include a LOS/NLOS determination unit 610 and an LOS/NLOS operation unit 620.
- the processor 1930 of the base station 1900 described later may perform the operations of the LOS/NLOS determination unit 610 and the LOS/NLOS operation unit 620 of the base station, and the processor 2030 of the terminal 2000 described later may perform the operations of the LOS/NLOS determination unit 610 and the LOS/NLOS operation unit 620 of the terminal.
- the LOS/NLOS determination unit 610 may determine the existence of a visible path using a received signal strength (RSS) or FSPL difference after measuring a multi-band channel.
- RSS received signal strength
- the LOS/NLOS determination unit 610 may determine the existence of a visible path through a power delay profile (PDP) estimation result after measuring a multi-band channel.
- the determination of whether or not there is a visible path through the power delay profile is the size of the main path signal of the radio wave calculated as the channel impulse response by performing an inverse Fourier Transform (IFT) on the channel frequency response result, the number of effective channel taps, Alternatively, it may be performed using at least one of a statistically calculated Root Mean Squared Delay (RMS Delay) and delay spread.
- IFT inverse Fourier Transform
- RMS Delay Root Mean Squared Delay
- a visible path channel result may be reported as uplink or downlink.
- the LOS/NLOS operation unit 620 when the base station and the terminal secure the visible path channel, the LOS/NLOS operation unit 620 according to an embodiment of the present disclosure performs waveform operation, scheduling, and reference signal density (reference signal density) suitable for the visible path channel characteristics. It is possible to perform transmission operations using visible path channel characteristics such as density conversion and propagation-based position estimation.
- FIG. 7 is a flowchart of a method for a base station to identify visible path channels in a wireless communication system according to an embodiment of the present disclosure.
- the base station may receive a reference signal for measuring a channel in each multi-band from the terminal.
- a base station may receive a random access preamble from a terminal in each of multiple bands.
- the base station may determine whether the channel is a visible path or a non-visible path for each of the multi-bands based on the random access preambles received in each of the multi-bands. For example, the base station may identify a minimum propagation distance between the terminal and the base station based on the random access preamble.
- the base station may determine received power of the random access preamble based on the minimum propagation distance.
- the base station determines that the channel is a visible path or a non-visible path for each of the multiple bands based on the received power of the random access preamble received in each of the multiple bands and the threshold power value of the frequency band in which the random access preamble is received. You can determine if it is a visible path.
- the received power of the random access preamble received in the first frequency band is greater than the threshold power value for the first frequency band
- the random access preamble received in the second frequency band is received If the power is greater than the threshold power value for the second frequency band, the channel may be identified as a visible path channel.
- the base station can receive a reference signal for measuring a channel in each of the multiple bands when it is determined that the channel is an invisible path in at least one of the multiple bands.
- a multi-band according to an embodiment of the present disclosure may include a first frequency band and a second frequency band.
- the number of frequency bands included in the multi-band is not limited to two, and at least two frequency bands may be included.
- Each frequency band included in the multi-band may mean a frequency band that is physically separated to the extent that a difference between the corresponding frequency bands can be revealed.
- the first frequency band may mean a frequency band of 6 GHz or less
- the second frequency band may mean a frequency band of 6 GHz or more.
- Multi-band may mean at least two frequency bands having different characteristics.
- the path loss exponent (n LOS ) in the visible path may be a value of 1.1 to 1.7 at 28 GHz and 73 GHz.
- the path loss exponent (n NLOS ) in the invisible path may be between 2.7 and 5.3 at 28 GHz and 73 GHz. That is, the path loss index (n NLOS ) in the invisible path may be greater than the path loss index (n LOS ) in the visible path.
- the shadowing value may be a variance value.
- both 28 GHz and 73 GHz may have small variance values in the visible path.
- the dispersion value tends to increase as the frequency increases in the invisible path.
- the high frequency band and the low frequency band have different characteristics.
- a base station and a terminal may identify visible path channels using multi-bands having different characteristics, or transmit and receive data between the base station and the terminal using the visible path channels.
- the above-described path loss index and shadowing value for each multi-band are values that may vary depending on the environment.
- the path loss index and shadowing value for each multi-band may be preset values.
- a multi-band according to an embodiment of the present disclosure may include at least two frequency bands separated by a value greater than a preset frequency difference.
- a preset frequency difference which is a difference between multiple frequency bands, may be determined according to the environment.
- the preset frequency difference may be determined based on at least one of a path loss index for each multi-band, a shadowing value, and a carrier frequency value for each multi-band.
- Resources for transmitting uplink signals by the UE may be determined based on whether the UE is capable of simultaneous uplink transmission (multi-band UL simultaneous TX) for each of multiple bands.
- a UE When a UE according to an embodiment of the present disclosure transmits an uplink (eg, Preamble or RS) to a base station, whether or not the UE can perform simultaneous uplink transmission for each of multiple bands is based on capability information of the UE.
- capability information of the UE can be determined by the capability information of the terminal.
- the capability information of the terminal may include information on whether the terminal is a device corresponding to an integrated access and backhaul (IAB) node, information on whether the terminal is a device corresponding to a UE, and the like.
- IAB integrated access and backhaul
- whether or not the terminal can perform simultaneous uplink transmission for each of the multi-bands considers conditions such as whether the transmission power value of the terminal is greater than the transmission threshold power value (eg, PcMax > Threshold(Tx)).
- the transmission threshold power value eg, PcMax > Threshold(Tx)
- a resource for the UE to transmit a signal in a low frequency band may be determined according to a predetermined method there is. For example, a resource for transmitting a signal in a high frequency band by a terminal uses the highest frequency at which the terminal can operate in the same time ((partially) overlapped duration) in which some or all time domains overlap. It may be determined as a resource that can be selected when transmitting a signal (occasion).
- a resource for transmitting a signal in a high frequency band is predefined in relation to a resource of a selected low frequency band. It can be determined as a resource.
- the resource for the UE to transmit a signal in the low frequency band is determined according to a predetermined method, or , may be determined as a predetermined resource in relation to a resource of a high frequency band.
- a resource for the terminal to transmit a signal in a high frequency band may be determined as a predetermined resource related to a resource of a selected low frequency band.
- a resource for transmitting a signal in a high frequency band by a UE may be determined on a first occasion after ⁇ T (band switching time, or a time determined by the standard).
- the resource for the terminal to transmit a signal in the high frequency band is from ⁇ T1 (band switching time, or a time determined by the standard) to before ⁇ T2 (a predetermined time or a time determined by an offset with ⁇ T1) It can be determined as the highest frequency occasion during the period.
- the base station may determine whether a channel is a visible path or a non-visible path for each multi-band based on the reference signal.
- a base station may determine whether a channel is a visible path channel for each multi-band based on a channel impulse response of a reference signal.
- the base station may determine the delay power value of the reference signal received in the first frequency band based on the channel impulse response of the reference signal received in the first frequency band. Also, the base station may determine a delay power value of the reference signal received in the second frequency band based on the channel impulse response of the reference signal received in the second frequency band.
- the base station has a power value corresponding to a value between the maximum reception delay power value and the threshold power value of the reference signal received in the first frequency band, based on the channel impulse response of the reference signal received in the first frequency band.
- a path having may be determined as the first effective invisible path.
- the base station determines a power value corresponding to a value between the maximum reception delay power value and the threshold power value of the reference signal received in the second frequency band, based on the channel impulse response of the reference signal received in the second frequency band.
- a path having the second effective invisible path may be determined.
- the base station may determine the first RMS delay spread value of the reference signal received in the first frequency band based on the channel impulse response of the reference signal received in the first frequency band.
- the base station may determine a second RMS delay spread value of the reference signal received in the second frequency band based on the channel impulse response of the reference signal received in the second frequency band.
- the base station can identify the corresponding channel as a visible path channel when it is determined that the channel is a visible path in each of the multi-bands.
- the received power of the random access preamble received in the first frequency band is greater than the threshold power value for the first frequency band
- the random access preamble received in the second frequency band When the received power is greater than the threshold power value for the second frequency band, the channel may be identified as a visible path channel.
- a delay power value of a reference signal received in a first frequency band is greater than a threshold power value determined for the first frequency band, and a delay power value of a reference signal received in a second frequency band. If it is greater than the threshold power value determined for this second frequency band, the channel can be identified as a visible path channel.
- the number of first effective invisible paths is smaller than the reference number of effective invisible paths determined for a first frequency band, and the number of second effective invisible paths is determined for a second frequency band. If the number is smaller than the determined effective non-visible path reference number, the channel may be identified as a visible path channel.
- the base station is configured when the first RMS delay spread value is smaller than the reference regional spread value for the first frequency band and the second RMS delay spread value is smaller than the reference regional spread value for the second frequency band.
- the channel can be identified as a visible path channel.
- the base station may transmit at least one of identification result information on the visible path channel or a signal generated based on the characteristic of the visible path channel to the terminal.
- a base station may determine at least one value of a CP size or a reference signal density based on a characteristic of a visible path channel.
- the base station may generate a signal including data or a reference signal based on the determined value, and transmit the generated signal to the terminal.
- a base station may receive a reference signal request for measuring a location of a terminal from a terminal.
- the base station may transmit a reference signal for measuring the position of the terminal to the terminal.
- the base station may receive, from the terminal, based on a reference signal for measuring the position of the terminal, whether a visual path channel exists between the terminal and the base station and location information of the terminal. In this case, whether the visual path channel exists and location information of the terminal may be determined based on the reference signal.
- FIG. 8 is a flowchart of a method for a terminal to identify visible path channels in a wireless communication system according to an embodiment of the present disclosure.
- the terminal may receive a reference signal for measuring a channel in each multi-band from the base station.
- the terminal may determine whether the channel is a line-of-sight or non-line-of-sight path for each of the multi-bands based on the reference signal.
- a UE may determine whether a channel is a visible path channel for each multi-band based on a channel impulse response of a reference signal.
- the terminal may determine a delay power value of the reference signal received in the first frequency band based on the channel impulse response of the reference signal received in the first frequency band.
- the terminal may determine a delay power value of the reference signal received in the second frequency band based on the channel impulse response of the reference signal received in the second frequency band.
- the terminal based on the channel impulse response of the reference signal received in the first frequency band, the terminal has a power value corresponding to a value between the maximum reception delay power value and the threshold power value of the reference signal received in the first frequency band.
- a path having may be determined as the first effective invisible path.
- the terminal determines a power value corresponding to a value between the maximum reception delay power value and the threshold power value of the reference signal received in the second frequency band based on the channel impulse response of the reference signal received in the second frequency band.
- a path having the second effective invisible path may be determined.
- the terminal may determine a first RMS (Root Mean Squared) delay spread value of the reference signal received in the first frequency band based on the channel impulse response of the reference signal received in the first frequency band.
- the terminal may determine a second RMS delay spread value of the reference signal received in the second frequency band based on the channel impulse response of the reference signal received in the second frequency band.
- step S830 when a channel is determined to be a visible path in each of the multi-bands, the terminal may identify the corresponding channel as a visible path channel.
- a delay power value of a reference signal received in a first frequency band is greater than a threshold power value determined for the first frequency band, and a delay power value of a reference signal received in a second frequency band. If it is greater than the threshold power value determined for this second frequency band, the channel can be identified as a visible path channel.
- the number of first effective invisible paths is smaller than the reference number of effective invisible paths determined for a first frequency band, and the number of second effective invisible paths is determined for a second frequency band. If the number is smaller than the determined effective non-visible path reference number, the channel may be identified as the visible path channel.
- the channel can be identified as a visible path channel.
- the terminal may transmit at least one of location information of the terminal, identification result information on the visible path channel, and a signal generated based on the characteristic of the visible path channel to the base station.
- a UE may determine a density of a reference signal based on a characteristic of a visible path channel.
- the UE may transmit the reference signal to the base station based on the determined density of the reference signal.
- a terminal may transmit a random access preamble in each of multiple bands to a base station.
- the visible path channel is determined based on the received power of the random access preamble received in each of the multi-bands and the threshold power value of the frequency band in which the random access preamble is received, and the received power of the random access preamble is based on the minimum propagation distance and the minimum propagation distance between the terminal and the base station may be identified based on the random access preamble.
- the UE can receive a reference signal for measuring a channel in each of the multi-bands.
- a terminal may transmit a reference signal request to a plurality of base stations.
- a terminal may receive reference signals from a plurality of base stations. Based on the reference signal, the terminal may determine whether a visible path channel exists between the terminal and a plurality of base stations and location information of the terminal.
- a UE may determine whether simultaneous uplink transmission is available for each multi-band based on capability information of the UE.
- the terminal may determine a resource for transmitting a signal based on whether simultaneous uplink transmission is available.
- FIG. 9 is a flowchart illustrating an operation method of a base station for estimating a visible path channel according to an embodiment of the present disclosure.
- the embodiment of FIG. 9 according to an embodiment of the present disclosure is described based on the operation of the base station, but the terminal may also perform some operations according to FIG. 9 .
- the base station or the terminal may perform SSB synchronization (SSB Synchronization) operation.
- SSB Synchronization SSB Synchronization
- the SSB synchronization operation is commonly used in a communication system (eg, LTE / LTE-A, 5G mobile communication system, or B5G / 6G mobile communication system developed later) It may include performing downlink time axis and frequency axis synchronization using a synchronization signal block (SSB).
- SSB synchronization signal block
- a base station according to an embodiment of the present disclosure may transmit an SSB to a terminal in a single band or in multiple bands.
- the base station may transmit the SSB to the terminal in the same time resource region or in a different time resource region.
- the terminal may succeed or fail to receive the SSB according to channel characteristics according to frequencies. Accordingly, when SSB synchronization is successful in some bands, the UE and the BS can synchronize the downlink time domain and frequency domain for other bands in which the SSB reception has failed.
- the base station may transmit the SSB by forming the same or different beams for a single band or multiple bands.
- a beam forming method of a base station may vary according to an operating frequency band of the base station.
- SSB synchronization using multi-bands (step 901) may include all a series of synchronization operations for different SSBs.
- the terminal and the base station for which downlink synchronization has been completed through the SSB synchronization operation in step 901 may perform a random access channel (RACH) operation using multi-band (hereinafter, a multi-band RACH process).
- RACH random access channel
- multi-band RACH process a random access channel
- random access may refer to a contention-based access procedure used by a terminal to perform uplink synchronization and transmit Msg-3 to a base station.
- a terminal may request uplink synchronization and uplink resource allocation from a base station through a physical channel called PRACH (Physical Random Access Channel).
- PRACH Physical Random Access Channel
- RACH operation 902 using multiple bands is performed in a communication system (e.g., LTE/LTE-A mobile communication system, 5G mobile communication system, Alternatively, operations of a base station and a terminal corresponding to a random access operation commonly used in a B5G/6G mobile communication system to be developed later) may be included.
- a communication system e.g., LTE/LTE-A mobile communication system, 5G mobile communication system, Alternatively, operations of a base station and a terminal corresponding to a random access operation commonly used in a B5G/6G mobile communication system to be developed later.
- the terminal may determine the minimum delay time ( ⁇ min ) between the base station and the terminal through the multi-band RACH operation 902.
- a method of determining the minimum delay time ( ⁇ min ) according to an embodiment of the present disclosure will be described later in detail with reference to FIG. 9 .
- FIGS. 10A and 10B are diagrams illustrating an example of estimating a delay time through transmission and reception of a downlink RACH signal according to an embodiment of the present disclosure.
- FIG. 10A illustrates an example of estimating a minimum delay time ( ⁇ min ) between a base station and a terminal through the multi-band RACH operation 902 shown in FIG. 9 in step 902.
- a terminal A 1002 located close to a base station 1001 at a distance of 0 km, and a terminal B 1003 located at a distance of 15 km are illustrated.
- the horizontal axis lattice 1004 may correspond to a subframe of the time axis region.
- a grid 1004 on a horizontal axis may mean a subframe 103 shown in FIG. 1 .
- the grid 1004 of the horizontal axis may be defined in units of slots 102 according to a communication system to be operated.
- a subframe is defined based on 1 ms.
- the base station 1001 may transmit information 1005 on a physical channel for downlink time-frequency domain synchronization and PRACH transmission to the terminal through an SSB synchronization operation.
- the time-frequency domain in which the terminal can transmit the PRACH to the base station is called PRACH Occasion.
- PRACH Occasion For example, in the case of 5G, since the PRACH Occasion is interlocked with the beam corresponding to the SSB transmitted by the base station in the SSB synchronization operation (step 901), the base station can know which SSB beam the terminal has selected based on the PRACH Occasion. .
- FIG. 10A illustrates a situation in which different PRACH Occasions are assigned to device A 1002 and device B 1003.
- PRACH Occasion A 1010 is allocated to UE A 1002
- PRACH Occasion B 1020 is allocated to UE B 1003.
- the random access preamble 1050 may include a cyclic prefix (CP) 1052, preamble data 1054, and a guard time 1056.
- Preamble data) 1054 can be used by cyclic shifting the Zadoff-Chu sequence having a small peak-to-average power ratio (PAPR), and the terminal and the base station can transmit and receive PRACH signals using the same sequence.
- CP 1052 may be 0.1 ms.
- the aforementioned random access preamble 1050 may include a random access preamble A 1012 transmitted by terminal A 1002 and a random access preamble B 1022 transmitted by terminal B 1003.
- the base station 1001 can receive the random access preamble A 1012 transmitted by the terminal A 1002 in the time axis region matching the grid of the time axis region of the base station 1001.
- the random access preamble B 1022 transmitted by terminal B 1003 may have a one-way propagation delay time depending on the distance from the base station 1001.
- the base station 1001 since there is a round-trip delay time in transmission and reception of radio waves, at a time delayed by 0.1 ms, which is twice the one-way propagation delay time of 0.05 ms, the base station 1001 transmits the random access preamble transmitted by the terminal B 1003 B 1022 can be received. Accordingly, the base station 1001 receives the random access preamble B 1022 in a time domain that is later than the detection window 1014, and thus can know the propagation delay time of the terminal B 1003.
- the base station 1001 may perform an uplink synchronization operation for determining a timing offset and the like through the propagation delay time of the terminal B 1003.
- the timing offset 1024 in the base station 1001 for terminal B 1003 may be 0.1 ms.
- the base station may identify a minimum delay time ( ⁇ min ) for receiving an uplink through the RACH operation 902.
- the base station can determine whether a corresponding channel is a visible path or a non-visible path by using a minimum delay time ( ⁇ min ) for receiving an uplink. The operation will be described later in more detail in the first embodiment.
- the base station may determine whether a corresponding channel is a visible path channel by determining whether received powers of the multi-bands are greater than threshold power values for the multi-bands.
- the base station can estimate the minimum propagation distance (d est ) between the terminal and the base station based on the minimum delay time ( ⁇ min ).
- the minimum propagation distance (d est ) may be determined as follows by multiplying the minimum delay time ( ⁇ min ) estimated in the RACH operation (step 902) by the propagation speed (c).
- the base station uses the calculated minimum propagation distance (d est ) to determine received power in a free space or visible path radio channel condition (for example, using a free-space path loss formula as follows) can
- P r (d FS ; ⁇ ) means the received power [W] when the distance between the antennas in free space is d FS
- P T means the transmit power [W] of the transmit antenna
- D t is the transmit It means the antenna gain of the antenna
- D r means the antenna gain of the receiving antenna
- ⁇ may mean the wavelength of radio waves.
- the received signal magnitude calculated in [Equation 5] is a value that varies depending on the magnitude and distance of frequency bands in multiple bands.
- P T , D t , D r are system parameters for calculating received power in a mobile communication system (eg, an LTE/LTE-A mobile communication system, a 5G mobile communication system, or a B5G/6G mobile communication system to be developed in the future) can be P T , D t , and D r may be values already calculated and known to the base station and the terminal. Alternatively, the base station and the terminal may obtain corresponding values through information transmitted and received in uplink and downlink control signals, for example, RRC Connection.
- the wavelength of the radio wave is the property of the radio wave ( ), it can be defined by replacing it with frequency as follows.
- the base station may set threshold power for multiple bands using [Equation 6] described above.
- multiple bands may be divided into sub-6 GHz bands and higher bands, named sub6G and mm&THz, and respective transmission frequencies may be referred to as f sub6G and f mm&THz .
- the threshold power f sub6G and f mm&THz for the two bands proposed in the present disclosure can be set as follows by [Equation 7].
- the base station receives power in multi-band. class may be compared with the threshold power values P th,sub6G and P th,mm&THz (that is, the threshold power value calculated in [Equation 7]). For example, the base station may determine whether the power value of the signal received in the low frequency band is greater than the threshold power value of the low frequency band and the power value of the signal received in the high frequency band is greater than the threshold power value of the high frequency band.
- the base station determines it as an LOS channel and Operation (visible path channel operation) (step 910) may be performed.
- the base station receives the power of the signal received through the visible path as the largest received power in the shortest radio wave arrival time, so the base station receives the signal according to the above method
- a comparison of power and threshold power can be performed.
- the power of a signal received through a visible path channel does not always include only the power of a signal received through a path directly reaching a base station. For example, since various waves are received by the base station through reflection, diffraction, refraction, etc., the received power may be increased or attenuated due to constructive interference.
- the base station can identify the visible path through comparison of received power and threshold power values for each multi-band in step 903 . Through FIGS. 11 and 12 , characteristics of received power of the visible path and the non-visible path can be confirmed.
- 11A and 11B are diagrams illustrating results of measuring received signal strengths of a visible path channel and a non-visible path channel according to an embodiment of the present disclosure.
- 11a and 11b are measurement results showing the received power strength of the visible path and the non-visible path according to the distance, and are described in reference (Xiao, Zhuoling, et al. "Non-line-of-sight identification and mitigation using received signal strength). .” IEEE Transactions on Wireless Communications 14.3 (2014): 1689-1702).
- FIG. 11A is a diagram illustrating received signals of a visible path channel and a non-visible path channel when the x-axis distance is a linear unit.
- FIG. 11B is a diagram in which the x-axis distance is scaled in a logarithmic scale, but shows the same result as in FIG. 11A.
- the visible path channel can be identified through the method of step 903 described above.
- 12A and 12B are diagrams illustrating path attenuation measurement results of a visible path channel and a non-visible path channel according to an embodiment of the present disclosure.
- 12a and 12b are graphs showing the path attenuation of the visible path and the non-visible path measured in the 28 GHz and 73 GHz bands, referenced (Deng, Sijia, Mathew K. Samimi, and Theodore S. Rappaport. "28 GHz and 73 GHz millimeter-wave indoor propagation measurements and path loss models.” 2015 IEEE International Conference on Communication Workshop (ICCW) . IEEE, 2015).
- 12A and 12B also show that there is a difference in characteristics between the visible path and the non-visible path, similarly to FIGS. 11A and 11B. Accordingly, FIGS. 12A and 12B also show that the base station can identify the visible path channel through the method of step 903 described above.
- the base station simultaneously receives and calculates the magnitude of the received signal measured for each of the multiple bands, rather than using only a received signal for a single band.
- the attenuation of a radio wave propagating through an invisible path is greater in the ultra-high frequency band of the mmWave/THz band of 6 GHz or higher compared to the low frequency band of 6 GHz or lower. That is, while the received power fluctuates greatly due to radio waves received through the non-visible path below 6 GHz, relatively stable results can be obtained at 6 GHz or higher. Therefore, since the base station uses the magnitude of the received signal using both bands at the same time, the accuracy of determining whether or not there is a visible path can be dramatically improved compared to the case of measuring using only a single band.
- the base station may receive a reference signal for channel measurement in multiple bands from the terminal. Also, in step 905, the base station may calculate a channel impulse response for the reference signal.
- the reference signal may include a sounding reference signal (SRS) received through an uplink.
- SRS sounding reference signal
- a terminal may generate a reference signal allocated to a multi-band radio resource.
- the reference signal generation and allocation method follows the reference signal generation and allocation method generally defined in LTE/LTE-A, 5G, B5G, and 6G communication systems.
- DMRS defined in LTE/LTE-A and 5G ( Demodulation Reference Signal) and SRS transmission operation.
- the terminal may transmit a reference signal to the base station by allocating radio resources in the frequency domain. At this time, the terminal may transmit an uplink reference signal to the base station in multiple bands for channel measurement.
- the base station based on the reference signal received from the terminal, the channel frequency response of the reference signal ( ) can be inverse Fourier transformed.
- the base station channel impulse response of the reference signal for each of the multi-bands ( ) can be estimated or determined.
- a base station calculates a channel impulse response (h sub6G ( ⁇ K )) for a reference signal received at a low frequency and a channel impulse response (h mm&THz ( ⁇ K )) for a reference signal received at a high frequency. can decide
- the base station and the terminal may perform a downlink reference signal transmission/reception operation for calculating a channel impulse response.
- the downlink reference signal may include a DMRS signal.
- the base station can identify whether a visible path channel exists using a channel impulse response to a reference signal received in each of the multi-bands.
- a base station or a terminal may identify a visible path channel using at least one of the 2-1 embodiment, 2-2 embodiment, or 2-3 embodiment described below.
- the base station or the terminal may determine the presence or absence of a visible path through a power delay profile (PDP) or an intensity delay profile (IDP) obtained as a channel impulse response.
- PDP power delay profile
- IDP intensity delay profile
- a channel impulse response to a reference signal transmitted in a low frequency band is greater than a threshold power value for the low frequency band (ie, h sub6G ( ⁇ 0 ) > h th , sub6G )
- a threshold power value for the low frequency band ie, h sub6G ( ⁇ 0 ) > h th , sub6G
- the channel between the base station and the terminal is a visible path channel can be determined by (i.e. h sub6G ( ⁇ 0 ) > h th , sub6G & h mm&THz ( ⁇ 0 ) > h th , mm&THz )
- 13A, 13B, and 13C are diagrams illustrating example power delay distributions and threshold voltages of visible and invisible path channels according to an embodiment of the present disclosure.
- a difference between a visible path channel (LOS Channel) and a non-visible path channel (NLOS Channel) is shown for a multipath channel reaching each delay time.
- LOS Channel visible path channel
- NLOS Channel non-visible path channel
- the threshold power 1315 may be set using a result calculated according to [Equation 7].
- 13B and 13C are diagrams for explaining a method of identifying visible path channels according to the 2-1 embodiment by using multiple bands according to an embodiment of the present disclosure.
- FIG. 13B illustrates a channel impulse response in a low frequency band (eg, Sub 6 GHz) according to an embodiment of the present disclosure
- FIG. 13C illustrates a channel impulse response in a high frequency band (eg, Above 6 GHz) according to an embodiment of the present disclosure. Shows the channel impulse response at Referring to FIG. 13B , only a single path 1320 may exist in the channel impulse response in a low frequency band (eg, Sub 6 GHz).
- FIG. 13C several visible path channels 1330 may be received in a high frequency band (eg, Above 6 GHz) due to fine delay resolution due to a wide frequency bandwidth.
- the presence or absence of the visible path channel can be analyzed with higher accuracy than in the first embodiment.
- a base station or terminal uses a minimum delay power value P( ⁇ 0 ) 1320 for a reference signal transmitted in a low frequency band for a multi-band channel and a threshold power value for the low frequency band (P th , sub6G ) 1325, and simultaneously compare the minimum delay power value P( ⁇ 0 ) 1330 for the reference signal transmitted in the high frequency band and the threshold power value (P th , mm&THz ) 1335 for the high frequency band.
- the base station or terminal may determine the corresponding channel as a visible path channel and perform the visible path channel operation 910 .
- the base station or terminal may analyze even the multipath components of the channel impulse response to determine whether there is a visible path channel. For example, the base station or the terminal may determine the presence or absence of a visual path channel through the number of other paths within a predetermined size range based on the size of the minimum delay power P( ⁇ 0 ) of the channel impulse response.
- the base station or the terminal may analyze even the multipath components of the channel impulse response to determine whether there is a visible path channel. For example, the base station or the terminal may determine the presence or absence of a visual path channel through the number of other paths within a predetermined size range based on the size of the minimum delay power P( ⁇ 0 ) of the channel impulse response.
- 14a, 14b, 14c, and 14d are diagrams for explaining a method of determining power delay distributions and effective invisible paths of visible and invisible path channels according to an embodiment of the present disclosure.
- NLOS paths non-visible path channels
- FIG. 14B it can be seen that there are 8 invisible path channels 1425 in the case of invisible path channels. That is, when checking the visible path channel of FIG. 14A, a value (for example, 30 dB) lower than the received power 1414 of the reference value ⁇ 0 (ie, the maximum received power in the visible path channel) by the threshold power 1410. 1416) and the maximum received power 1414 may be determined as a range 1418 capable of determining an effective invisible path.
- Paths having a received power value within the corresponding range 1418 may be determined as effective NLOS paths 1412, and according to the example of FIG. 14A, there are four effective non-visible paths 1412 can confirm that Similarly, when checking the invisible path channel of FIG. 14B, the threshold power 1420 (eg, 30 dB) is lower than the received power 1424 of the reference value ⁇ 1 (ie, the maximum received power in the invisible path channel). A range between the value 1426 and the maximum received power 1424 may be determined as a range 1428 for determining an effective invisible path. According to the example of FIG. 14B , it can be confirmed that there are 8 effective invisible paths 1422 .
- the threshold power 1420 eg, 30 dB
- ⁇ 1 ie, the maximum received power in the invisible path channel
- a range between the value 1426 and the maximum received power 1424 may be determined as a range 1428 for determining an effective invisible path. According to the example of FIG. 14B , it can be confirmed that there are 8 effective invisible paths 14
- paths having a power value within the difference between the maximum power value and the threshold power in each frequency band are determined as effective NLOS paths, and the number of effective non-visible paths in the frequency band can be determined.
- the number of effective non-visible paths 1412 is small because the size of the received power of the visible path is large in the case of the visible path channel, but in the case of the invisible path channel, most of the received power sizes are similar
- the number of effective invisible paths 1422 calculated is rapidly increased compared to the visible path channels. Accordingly, the presence or absence of visible path channels can be divided based on the number of effective invisible paths.
- the accuracy of the operation of determining the visible path channel according to the 2-2 embodiment can be further improved. This is because, as described above, when a wide band is used in a high frequency band, delay resolution increases in the high frequency band. When the delay resolution increases, the number of invisible path channels also greatly changes accordingly, so it becomes easier to distinguish effective invisible path channels compared to low-frequency bands.
- 14c and 14d are diagrams illustrating a method of identifying visible path channels according to a 2-2 embodiment using multiple bands according to an embodiment of the present disclosure.
- FIG. 14c shows the number of effective non-visible paths and effective non-visible paths in a low frequency band (eg, Sub 6 GHz) according to an embodiment of the present disclosure, and FIG. It shows the number of effective non-visible paths and effective non-visible paths in a frequency band (eg Above 6 GHz).
- a low frequency band eg, Sub 6 GHz
- FIG. It shows the number of effective non-visible paths and effective non-visible paths in a frequency band (eg Above 6 GHz).
- the threshold power 1430 (for example, 30 dB) is higher than the received power (P( ⁇ 0 )) 1434 (ie, the maximum received power at sub 6 GHz) of ⁇ 0 , which is a reference value.
- a range 1438 between the value 1436 as low as 1436 and the maximum received power P( ⁇ 0 ) 1434 may be determined as a range in which an effective invisible path can be determined.
- the value of the threshold power 1430 is described as 30 dB according to an embodiment of the present disclosure, the value of the threshold power 1430 is not limited to that value and may be set to other values.
- a base station or terminal may determine paths having received power values within the corresponding range 1438 as effective invisible paths 1422 . According to the example of FIG. 14C , it can be confirmed that there are four effective invisible paths.
- the threshold power 1440 (for example, 30 dB) is higher than the received power (P( ⁇ 0 )) 1444 of the reference value ⁇ 0 (ie, the maximum received power at above 6 GHz).
- a range 1448 between a value 1446 as low as 1446 and the maximum received power (P( ⁇ 0 )) 1444 may be determined as a range in which an effective invisible path can be determined.
- the value of the threshold power 1440 is described as 30 dB according to an embodiment of the present disclosure, the value of the threshold power 1440 is not limited to that value and may be set to other values.
- a base station or a terminal according to an embodiment of the present disclosure may determine paths having received power values within the corresponding range 1448 as effective invisible paths. According to the example of FIG. 14D , it can be confirmed that 23 effective invisible paths 1442 exist.
- the number of effective invisible paths (1432, 1442) having a power value falling within the effective invisible path determination range (1438, 1448) of each band included in the multi-band is It may be determined whether the number is smaller than the reference number of preset valid invisible paths.
- the reference number of effective invisible paths according to an embodiment of the present disclosure is a value that can be changed according to a propagation environment, a communication system, and the like, and is a value that can be preset by a user.
- the reference number of effective invisible paths may be set to different values for each channel. Alternatively, as another example, the reference value may be set to the same value for each channel.
- the reference number (n th,sub6G ) of effective invisible paths in the low frequency band (eg, sub 6GHz) is 5, and the reference number of effective invisible paths in the high frequency band (eg, above 6GHz) (n th, mm&THz ) may be set to 24, but as described above, it is not a value limited to one embodiment. As shown in FIG.
- the terminal or the base station may determine the corresponding channel as a visible path channel.
- the terminal or the base station may perform a visible path channel operation 910.
- the base station or the terminal may determine the presence or absence of a visible path channel using a Root Mean Square (RMS) delay spread of a channel impulse response.
- RMS Root Mean Square
- the power delay profile and channel response may be calculated through a statistical average as shown in [Equation 8] below.
- the average excess delay calculated through this power delay profile can be calculated with the following formula.
- L is the number of effective delay channels.
- the RMS delay spread value calculated in [Equation 10] is a measure of the degree to which taps of all delayed multi-path channels are distributed based on the average. Therefore, when the RMS delay spread value is large, the degree of dispersion is large, and when the RMS delay spread value is small, the degree of dispersion is small and is concentrated on the average.
- the RMS delay spread value is calculated based on the power delay profile (PDP) of the radio channel, it can be confirmed that the value tends to be small for visible path channels and large for non-visible path channels.
- the RMS delay spread value varies greatly depending on the number of received invisible path channels or their received power strength even for the same invisible path channel.
- the base station or terminal has a threshold delay spread value (Threshold Delay Spread) in a communication environment to be used ( ) to obtain a reference delay spread value in advance.
- the base station or terminal calculates the RMS delay spread value through the individual channel impulse response ( ) and a reference delay spread value, it is possible to determine the presence or absence of a visible path channel. Also in Embodiments 2-3, accuracy can be improved through multi-channel measurement. Referring to FIG. 14, the second to third embodiments will be described in more detail.
- 15A, 15B, 15C, and 15D are diagrams for explaining power delay distributions and root mean square delay spread results of visible and invisible path channels according to an embodiment of the present disclosure.
- the RMS delay spread values 1510 and 1530 calculated for the visible path channel and the invisible path channel are the reference delay spread value ( 1512, 1532) and there is no significant difference, which lowers the discrimination accuracy.
- the RMS delay spread value 1520 of the visible path channel and the RMS delay spread of the invisible path channel are obtained because the multipath attenuation is large and the number of multipaths is reduced at high frequency.
- the deviation of the value 1540 rapidly increases.
- the characteristics of the above-described high frequency band (above 6GHZ) can be confirmed with reference to FIG. 15B.
- the accuracy of determining the existence of the visible path channel can be increased compared to the conventional case of checking the visible path channel in a single frequency band.
- it has the advantage of reducing the false alarm rate through cross-validation of the low frequency band and the high frequency band.
- FIG. 15A showing the low-frequency visible path channel with FIG. 15C showing the non-visible path channel of the low-frequency band it can be seen that the visible path channel has a smaller RMS delay spread value ( ⁇ ⁇ ) 1510. there is. Also, similarly, comparing FIG. 15b showing the visible path channel in the high frequency band with FIG. 15d showing the non-visible path channel in the high frequency band, the visible path channel has a smaller RMS delay spread value ( ⁇ ⁇ ) 1522 can confirm that
- a base station or a terminal may first determine a threshold delay spread ( ⁇ th ) 1512 for a low frequency band. can In addition, the base station or terminal compares the RMS delay spread value ( ⁇ ⁇ ) 1510 determined through the individual channel impulse response in the low frequency band with the reference delay spread value 1512, and obtains the RMS delay spread value ( ⁇ ⁇ ) 1510 It may be determined whether or not the delay spread value ( ⁇ th ) 1512 for the low frequency band is smaller than the reference delay spread value ( ⁇ th ).
- the base station may first determine a threshold delay spread ( ⁇ th ) 1522 for the high frequency band. .
- the base station or terminal compares the RMS delay spread value ( ⁇ ⁇ ) 1520 determined through the individual channel impulse response in the high frequency band, and the RMS delay spread value ( ⁇ ⁇ ) 1520 determines the reference delay spread for the high frequency band. It can be determined whether it is smaller than the value ( ⁇ th ) 1522 .
- An RMS delay spread value ( ⁇ ⁇ ) 1510 for a low frequency band is smaller than a reference delay spread value ( ⁇ th ) 1512 for a low frequency band and a base station or terminal according to an embodiment of the present disclosure
- the base station or the terminal may determine the corresponding channel as a visible path channel.
- the terminal or base station performs a visible path channel operation 910 on the channel determined as the visual path channel can do.
- the LOS Operation 910 of FIG. 9 is at least one of the above-mentioned visible path channel determination methods of the first embodiment (step 903), the 2-1 embodiment, the 2-2 embodiment, and the 2-3 embodiment.
- the visible path channel may refer to an operation of improving the performance of the mobile communication system by utilizing the characteristic of the visible path channel.
- 15 to 17 are diagrams illustrating embodiments in which a base station and a terminal perform an LOS operation by utilizing characteristics of a visible path channel in a corresponding visible path channel when a visible path channel is identified.
- the method of operating the base station and the terminal using the visible path may mean performing an operation according to at least one of the 3-1 embodiment, the 3-2 embodiment, and the 3-3 embodiment, which will be described later. .
- 16 is a diagram illustrating symbol design in the time domain according to presence or absence of visible path channels according to an embodiment of the present disclosure.
- CP Cyclic Prefix
- ISI Inter-Symbol Interference
- the rear part of the symbol corresponding to about 7% of the symbol length can be used repeatedly in front of the symbol.
- the ratio of CP to symbol length is called CP Overhead.
- a factor used to determine CP Overhead may be an RMS delay spread value of a radio channel.
- the CP 1610 may be set to a length three to five times the RMS delay spread value ( ⁇ RMS ). This is to secure a stable ISI-free environment because the delay length varies depending on the wireless channel environment.
- the RMS delay spread value ( ⁇ RMS ) of the visible path channel can be reduced, and waste of CP overhead can be prevented.
- ⁇ RMS the RMS delay spread value
- the length of the CP 1630 used on the channel identified as the visible path channel may be a value determined by the user.
- the length of the CP 1630 may use a shorter CP than a conventionally used short CP.
- 17A and 17B are diagrams for explaining a method of reducing reference signal density and increasing multiplexing according to presence or absence of visible path channels according to an embodiment of the present disclosure.
- 17A illustrates a resource allocation method for reference signal transmission in a visual path channel environment according to an embodiment of the present disclosure.
- the visible path channel only a single path having a relatively large received power in the time domain may exist.
- the above description may mean having a constant channel frequency response over the entire radio resource block (RB) when analyzed in the frequency domain. Therefore, in the case of using the visible path channel, it is not necessary to measure the frequency response of the entire RB by densely arranging the reference signals in the frequency domain as in the conventional method.
- a reference signal is transmitted using a visible path channel according to an embodiment of the present disclosure, it is possible to estimate a channel using a small number of resources, and it is possible to use the remaining resources for data transmission.
- reference signal REs 1710 are conventionally allocated in a radio resource block, but one reference signal RE 1715, which is a smaller number than before, is allocated to a radio resource block in a visible path channel. can confirm that That is, when the base station transmits the DMRS to the terminal using the visible path channel, the density of the DMRS in the radio resource block may be reduced.
- the number of reference signal REs in FIG. 17A is an example and is not limited thereto.
- FIG. 17B is a diagram for explaining that reference signal transmission supporting more antenna ports than existing antenna ports is possible in a visible path channel environment according to another embodiment of the present disclosure.
- 12 antenna ports 1720 could be supported using frequency division multiplexing (FDM), time division multiplexing (TDM), and code division multiplexing (CDM).
- FDM frequency division multiplexing
- TDM time division multiplexing
- CDM code division multiplexing
- a base station or a terminal may transmit 24 antenna ports 1722 using different REs in the frequency domain.
- the base station or the terminal may apply CDM to 2 REs and apply 24 antenna ports 1724 . That is, unlike the conventional method of transmitting 12 antenna ports 1720, when using a visual path channel, since 24 antenna ports 1722 and 1724 can be used, more multiplexing capacity can be supported.
- 18A and 18B are examples illustrating a method of estimating a location of a terminal according to an embodiment of the present disclosure.
- 18A and 18B are diagrams for determining the presence or absence of a visual path channel through signal transmission and reception between a terminal 1804 and neighboring base stations 1801, 1802, and 1803 for position estimation of the terminal 1804 according to an embodiment of the present disclosure. It is a drawing showing the method.
- a terminal 1804 may estimate a channel through a reference signal (RS) received from nearby base stations 1801 , 1802 , and 1803 capable of transmitting and receiving.
- the terminal 1804 can estimate the location of the terminal 1804 through trilateration by calculating a delay time when the corresponding channel is a visible path channel.
- RS reference signal
- the terminal 1804 may request RS timing from a plurality of base stations located near the terminal 1804 during a waiting period.
- the terminal 1804 In order to measure the location of the terminal 1804 in a visible path channel environment, the terminal 1804 first provides a visible path to neighboring base stations base station A 1801, base station B 1802, and base station C 1803. Transmission of a reference signal for measuring the presence or absence of a channel may be requested.
- FIGS. 18A and 18B it is assumed that there are three base stations around the terminal 1804 for convenience of description. However, this is only an example, and a plurality of base stations may exist around the terminal 1804.
- the terminal 1804 may request transmission of a reference signal from a plurality of base stations located in the vicinity to which the terminal 1804 may request transmission of a reference signal.
- a reference signal may be transmitted from a plurality of base stations located in the vicinity to which the terminal 1804 may request transmission of a reference signal.
- the terminal 1804 may receive a reference signal from each of a plurality of base stations.
- the base stations 1801, 1802, and 1803 may transmit reference signals to the terminal 1804 in a measurement period in an order in which the reference signals requested from the terminal 1804 are not transmitted simultaneously.
- the terminal 1804 can select only the reference signal for the visual path channel from among the reference signals received through at least one neighboring base station.
- the terminal 1804 may check the existence of a visible path channel based on the selected reference signal, and report identification result information on the visible path channel to the base station.
- the terminal 1804 may determine whether a channel with each base station is a visual path channel based on reference signals received from a plurality of base stations. Based on the determination, the terminal 1804 may select at least three base stations (eg, base station A 1801, base station B 1802, and base station C 1803) having visible path channels with the terminal 1804.
- the terminal 1804 can also determine how much delay the signals (LOS A, LOS B, and LOS C) received from the base station through which the visual path channel is formed are received.
- the terminal 1804 may determine the location of the terminal 1804 based on the signals (LOS A, LOS B, and LOS C) received from the base station through which the visible path channel is formed and report the location to the base station.
- the terminal 1804 according to an embodiment of the present disclosure may transmit identification result information on the visible path channel to base station A 1801, base station B 1802, and base station C 1803 in which the visible path channel is formed.
- the identification result information on the visible path channel transmitted to base station A 1801, base station B 1802, and base station C 1803 may include information indicating that the visible path channel has been identified as existing between the terminal and the base station. .
- the identification result information on the visible path channel indicates that the visible path channel between the terminal and the base station is transmitted.
- Information indicating that it has been identified as non-existent (ie, non-visible path channel exists) may be included.
- the terminal 1804 or base stations 1801 , 1802 , and 1803 cooperatively communicating with each other can determine the existence of a visible path channel and estimate the location of the terminal 1804 .
- 19 is a data transmission/reception flowchart illustrating a method for identifying a visual path channel based on a random access preamble by a base station according to an embodiment of the present disclosure.
- the base station 1910 may receive a random access preamble in each of the multi-bands from the terminal 1920.
- the base station 1910 may determine whether a channel is a visible path or a non-visible path for each multi-band based on the random access preamble.
- the base station 1910 may identify the channel as a visible path channel when it is determined that the channel is a visible path in each of the multi-bands.
- the base station 1910 may transmit at least one of identification result information on the visible path channel or a signal generated based on the characteristic of the visible path channel to the terminal 1920.
- the base station 1910 when it is identified that the visible path channel exists, the base station 1910 performs a visual path according to at least one of the above-described 3-1, 3-2, and 3-3 embodiments. Channel operation can be performed.
- 20 is a data transmission/reception flowchart illustrating a method for a base station to identify a visible path channel based on a reference signal received from a terminal according to an embodiment of the present disclosure.
- the base station 2010 may determine a channel in at least one of the multi-bands as an invisible path based on the random access preamble.
- the base station 2010 may receive a reference signal for measuring a channel in each multi-band from the terminal 2020.
- the base station 2010 may determine whether a channel is a visible path or a non-visible path for each multi-band based on the reference signal.
- the base station 2010 may identify the channel as a visible path channel when it is determined that the channel is a visible path in each of the multi-bands.
- the base station 2010 may transmit at least one of identification result information on the visible path channel or a signal generated based on the characteristic of the visible path channel to the terminal 2020.
- the base station 1910 when it is identified that the visible path channel exists, the base station 1910 performs the visible path according to at least one of the above-described 3-1, 3-2, and 3-3 embodiments. Channel operation can be performed.
- 21 is a data transmission/reception flowchart illustrating a method for identifying a visual path channel based on a reference signal received from a base station by a terminal according to an embodiment of the present disclosure.
- the base station 2110 may determine a channel in at least one of the multi-bands as an invisible path based on the random access preamble.
- the terminal 2120 may receive a reference signal for measuring a channel in each multi-band from the base station 2110.
- the terminal 2120 may determine whether a channel is a visible path or a non-visible path for each multi-band based on the reference signal.
- the terminal 2120 may identify the channel as a visible path channel when it is determined that the channel is a visible path in each of the multi-bands.
- the terminal 2120 may transmit at least one of location information of the terminal, identification result information on visible path channels, and signals generated based on characteristics of visible path channels to the base station 2110.
- the terminal 2120 when it is identified that the visible path channel exists, the terminal 2120 performs a visible path according to at least one of the above-described 3-1, 3-2, and 3-3 embodiments. Channel operation can be performed.
- FIGS. 22 and 23 A transmission/reception method between a base station and a terminal for applying a method for transmitting and receiving a downlink control channel and a data channel in the communication system corresponding to the above embodiment is shown. It may work according to the example.
- 22 is a block diagram illustrating the structure of a terminal according to an embodiment of the present disclosure.
- a terminal 2200 may include a transceiver 2210, a memory 2220, and a processor 2230. According to the communication method of the terminal described above, the transceiver 2210, the processor 2230, and the memory 2220 of the terminal 2200 may operate. However, components of the terminal 2200 are not limited to the above example. For example, the terminal 2200 may include more or fewer components than the aforementioned components. In addition, the transceiver 2210, the processor 2230, and the memory 2220 may be implemented as a single chip. Also, the processor 2230 may include one or more processors.
- the transmitting/receiving unit 2210 collectively refers to a receiving unit of the terminal 2200 and a transmitting unit of the terminal, and may transmit/receive signals to/from a network entity, a base station, or other terminals. Signals transmitted to and from a network entity, base station, or other terminal may include control information and data.
- the transceiver 2210 may include an RF transmitter for up-converting and amplifying the frequency of a transmitted signal, and an RF receiver for low-noise amplifying a received signal and down-converting the frequency.
- the transceiver 2210 may receive a signal through a wireless channel, output the signal to the processor 2230, and transmit the signal output from the processor 2230 through the wireless channel.
- the memory 2220 may store programs and data necessary for the operation of the terminal 2200 . Also, the memory 2220 may store control information or data included in a signal obtained from the terminal.
- the memory 2220 may include a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD, or a combination of storage media. In addition, the memory 2220 may not exist separately but may be included in the processor 2230.
- the processor 2230 may control a series of processes so that the terminal 2200 may operate according to the above-described embodiment of the present disclosure.
- the processor 2230 may receive a control signal and a data signal through the transceiver 2210 and process the received control signal and data signal.
- the processor 2230 may process the control signal and data.
- a signal may be transmitted through the transceiver 2210.
- the processor 2230 receives a signal for measuring a channel in each of the multi-bands from the base station, and based on the signal, the null line-of-sight path (Line-of-Sight) for each of the multi-bands. ) channel. In response to determining that a visible path channel exists in each of the multi-bands, the processor 2230 may identify the channel as a visible path channel and transmit data to the base station based on the visible path channel.
- FIG. 23 is a block diagram illustrating the structure of a base station according to an embodiment of the present disclosure.
- a base station 2300 may include a transceiver 2310, a memory 2320, and a processor 2330. According to the communication method of the base station described above, the transceiver 2310, the processor 2330, and the memory 2320 of the base station may operate. However, components of the base station 2300 are not limited to the above example. For example, the base station 2300 may include more or fewer components than the aforementioned components. In addition, the transceiver 2310, the processor 2330, and the memory 2320 may be implemented as a single chip. Also, the processor 2330 may include one or more processors.
- the transmitting/receiving unit 2310 collectively refers to a receiving unit of the base station 2300 and a transmitting unit of the base station, and may transmit/receive a signal to/from a network entity, a terminal, or another base station. Signals transmitted and received to and from network entities, other base stations, or terminals may include control information and data.
- the transceiver 2310 may include an RF transmitter for up-converting and amplifying the frequency of a transmitted signal, and an RF receiver for low-noise amplifying a received signal and down-converting its frequency.
- the transceiver 2310 may receive a signal through a wireless channel, output the signal to the processor 2330, and transmit a signal output from the processor 2330 through a wireless channel.
- the memory 2320 may store programs and data necessary for the operation of the base station 2300 . Also, the memory 2320 may store control information or data included in a signal obtained from the base station 2300 .
- the memory 2320 may include a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD, or a combination of storage media. In addition, the memory 2320 may not exist separately but may be included in the processor 2330.
- the processor 2330 may control a series of processes so that the base station 2300 can operate according to the above-described embodiment of the present disclosure.
- the processor 3130 may receive a control signal and a data signal through the transceiver 3110 and process the received control signal and data signal.
- the processor 3130 may process the control signal and data.
- a signal may be transmitted through the transceiver 3110.
- the processor 2330 controls the transceiver 2310 to receive a signal for measuring a channel in each of the multi-bands from the terminal, and based on the signal, for each of the multi-bands. It may be determined whether the channel is a line-of-sight channel. Further, in response to determining that the visible path channel exists in each of the multi-bands, the processor 2330 identifies the channel as the visible path channel and transmits data to the terminal based on the visible path channel. The transceiver 2310 may be controlled.
- the processor 2330 controls the transceiver 2310 to receive random access preambles in each of the multi-bands, and receives power of the random access preambles received in each of the multi-bands and random Based on the threshold power value of the frequency band in which the access preamble is received, it may be determined whether the channel is a visible path channel.
- the above-described embodiment can be written as a program that can be executed on a computer, and can be implemented in a general-purpose digital computer that operates the program using a computer-readable medium.
- the structure of data used in the above-described embodiment can be recorded on a computer readable medium through various means.
- the above-described embodiments may be implemented in the form of a computer program product including a recording medium including instructions executable by a computer, such as program modules executed by a computer.
- methods implemented as software modules or algorithms may be stored in a computer-readable recording medium as codes or program instructions that can be read and executed by a computer.
- Computer readable media may be any recording media that can be accessed by a computer, and may include volatile and nonvolatile media, removable and non-removable media.
- Computer-readable media include magnetic storage media such as ROM, floppy disks, hard disks, etc., and may include optical read media such as CD-ROM and DVD storage media, but are not limited thereto.
- computer readable media may include computer storage media and communication media.
- a plurality of computer-readable recording media may be distributed among computer systems connected by a network, and data stored on the distributed recording media, for example, program instructions and codes, may be executed by at least one computer. there is.
- the device-readable storage medium may be provided in the form of a non-transitory storage medium.
- 'non-temporary storage medium' only means that it is a tangible device and does not contain signals (e.g., electromagnetic waves), and this term refers to the case where data is stored semi-permanently in the storage medium and temporary It does not discriminate if it is saved as .
- a 'non-temporary storage medium' may include a buffer in which data is temporarily stored.
- the method according to various embodiments disclosed in this document may be provided by being included in a computer program product.
- Computer program products may be traded between sellers and buyers as commodities.
- a computer program product is distributed in the form of a device-readable storage medium (e.g. compact disc read only memory (CD-ROM)), or through an application store (e.g. Play StoreTM) or on two user devices (e.g. It can be distributed (eg downloaded or uploaded) online, directly between smartphones.
- a device-readable storage medium e.g. compact disc read only memory (CD-ROM)
- an application store e.g. Play StoreTM
- It can be distributed (eg downloaded or uploaded) online, directly between smartphones.
- a part of a computer program product eg, a downloadable app
- a device-readable storage medium such as a memory of a manufacturer's server, an application store server, or a relay server. It can be temporarily stored or created temporarily.
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Abstract
Description
Claims (15)
- 무선 통신 시스템에서 기지국이 가시 경로 채널을 식별하는 방법에 있어서,단말로부터, 다중 대역 각각에서 채널을 측정하기 위한 참조 신호를 수신하는 단계;상기 참조 신호에 기초하여, 상기 다중 대역 각각에 대해 상기 채널이 가시 경로(Line-of-Sight), 또는 비 가시 경로인지를 결정하는 단계;상기 다중 대역 각각에서 상기 채널이 가시 경로로 결정된 경우, 상기 채널을 상기 가시 경로 채널로 식별하는 단계; 및상기 단말로 상기 가시 경로 채널에 대한 식별 결과 정보, 또는 상기 가시 경로 채널의 특성에 기초하여 생성된 신호 중 적어도 하나를 전송하는 단계;를 포함하는, 방법.
- 제1항에 있어서,상기 단말로부터, 상기 다중 대역 각각에서 랜덤 엑세스 프리엠블을 수신하는 단계; 및상기 다중 대역 각각에서 수신된 상기 랜덤 엑세스 프리엠블에 기초하여, 상기 다중 대역 각각에 대해 상기 채널이 가시 경로, 또는 비 가시 경로인지를 결정하는 단계;를 더 포함하고,상기 단말로부터, 상기 다중 대역 각각에서 채널을 측정하기 위한 참조 신호를 수신하는 단계; 는,상기 랜덤 액세스 프리엠블에 기초하여, 상기 다중 대역 중 적어도 하나의 대역에서 채널이 비 가시 경로로 결정된 경우, 상기 다중 대역 각각에서 채널을 측정하기 위한 참조 신호를 수신하는 단계;를 포함하는, 방법.
- 제2항에 있어서, 상기 랜덤 엑세스 프리엠블에 기초하여, 상기 다중 대역 각각에 대해 상기 채널이 가시 경로, 또는 비 가시 경로인지를 결정하는 단계;는,상기 랜덤 엑세스 프리엠블에 기초하여, 상기 단말과 상기 기지국 사이의 최소 전파 거리를 식별하는 단계;상기 최소 전파 거리에 기초하여, 상기 랜덤 엑세스 프리엠블의 수신 전력을 결정하는 단계; 및상기 다중 대역 각각에서 수신된 상기 랜덤 엑세스 프리엠블의 수신 전력과 상기 랜덤 엑세스 프리엠블이 수신된 주파수 대역의 문턱 전력 값에 기초하여, 상기 다중 대역 각각에 대해 상기 채널이 가시 경로, 또는 비 가시 경로인지를 결정하는 단계; 를 포함하는, 방법.
- 제2항에 있어서, 상기 랜덤 엑세스 프리엠블에 기초하여, 상기 다중 대역 각각에 대해 상기 채널이 가시 경로, 또는 비 가시 경로인지를 결정하는 단계;는,제1 주파수 대역에서 수신한 랜덤 엑세스 프리엠블의 수신 전력이 상기 제1 주파수 대역에 대한 문턱 전력 값보다 크고, 제2 주파수 대역에서 수신한 랜덤 엑세스 프리엠블의 수신 전력이 상기 제2 주파수 대역에 대한 문턱 전력 값보다 큰 경우, 상기 채널을 상기 가시 경로 채널로 식별하는 단계;를 포함하는, 방법.
- 제1항에 있어서, 상기 참조 신호에 기초하여, 상기 다중 대역 각각에 대해 상기 채널이 가시 경로, 또는 비 가시 경로인지를 결정하는 단계;는,제1 주파수 대역에서 수신한 참조 신호의 채널 임펄스 응답에 기초하여 상기 제1 주파수 대역에서 수신한 참조 신호의 지연 전력 값을 결정하는 단계; 및제2 주파수 대역에서 수신한 참조 신호의 채널 임펄스 응답에 기초하여 상기 제2 주파수 대역에서 수신한 참조 신호의 지연 전력 값을 결정하는 단계;를 포함하고,상기 채널을 상기 가시 경로 채널로 식별하는 단계;는,상기 제1 주파수 대역에서 수신한 참조 신호의 지연 전력 값이 상기 제1 주파수 대역에 대해 결정된 문턱 전력 값보다 크고, 상기 제2 주파수 대역에서 수신한 참조 신호의 지연 전력 값이 상기 제2 주파수 대역에 대해 결정된 문턱 전력 값보다 큰 경우, 상기 채널을 상기 가시 경로 채널로 식별하는 단계;를 포함하는, 방법.
- 제1항에 있어서, 상기 참조 신호에 기초하여, 상기 다중 대역 각각에 대해 상기 채널이 가시 경로, 또는 비 가시 경로인지를 결정하는 단계;는,제1 주파수 대역에서 수신한 참조 신호의 채널 임펄스 응답에 기초하여, 상기 제1 주파수 대역에서 수신한 참조 신호의 최대 수신 지연 전력 값과 문턱 전력 값과의 사이 값에 대응되는 전력 값을 갖는 경로를 제1 유효 비가시 경로로 결정하는 단계; 및제2 주파수 대역에서 수신한 참조 신호의 채널 임펄스 응답에 기초하여, 상기 제2 주파수 대역에서 수신한 참조 신호의 최대 수신 지연 전력 값과 문턱 전력 값과의 사이 값에 대응되는 전력 값을 갖는 경로를 제2 유효 비가시 경로로 결정하는 단계;를 포함하고,상기 채널을 상기 가시 경로 채널로 식별하는 단계;는,상기 제1 유효 비가시 경로의 개수가 상기 제1 주파수 대역에 대해 결정된 유효 비가시 경로 기준 개수보다 작고, 상기 제2 유효 비가시 경로의 개수가 상기 제2 주파수 대역에 대해 결정된 유효 비가시 경로 기준 개수보다 작은 경우, 상기 채널을 상기 가시 경로 채널로 식별하는 단계;를 포함하는, 방법.
- 제1항에 있어서, 상기 참조 신호에 기초하여, 상기 다중 대역 각각에 대해 상기 채널이 가시 경로, 또는 비 가시 경로인지 결정하는 단계;는,제1 주파수 대역에서 수신한 참조 신호의 채널 임펄스 응답에 기초하여 상기 제1 주파수 대역에서 수신한 참조 신호의 제1 RMS (Root Mean Squared) 지연 확산 값을 결정하는 단계; 및제2 주파수 대역에서 수신한 참조 신호의 채널 임펄스 응답에 기초하여 상기 제2 주파수 대역에서 수신한 참조 신호의 제2 RMS 지연 확산 값을 결정하는 단계;를 포함하고,상기 채널을 상기 가시 경로 채널로 식별하는 단계;는,상기 제1 RMS 지연 확산 값이 상기 제1 주파수 대역에 대한 기준 지역 확산 값 보다 작고, 상기 제2 RMS 지연 확산 값이 상기 제2 주파수 대역에 대한 기준 지역 확산 값 보다 작은 경우, 상기 채널을 상기 가시 경로 채널로 식별하는 단계;를 포함하는, 방법.
- 제 1항에 있어서, 상기 단말로 상기 단말의 위치 정보, 상기 가시 경로 채널에 대한 식별 결과 정보, 또는 상기 가시 경로 채널의 특성에 기초하여 생성된 신호 중 적어도 하나를 전송하는 단계;는,상기 가시 경로 채널의 특성에 기초하여, CP(Cyclic Prefix) 사이즈, 또는 참조 신호의 밀도 중 적어도 하나의 값을 결정하는 단계;상기 결정된 값에 기초하여, 데이터 또는 상기 참조 신호를 포함하는 신호를 생성하는 단계; 및상기 신호를 상기 단말로 전송하는 단계;를 포함하는, 방법.
- 제1항에 있어서,상기 단말로부터 상기 단말의 위치를 측정하기 위한 참조 신호 요청을 수신하는 단계;상기 단말로 상기 단말의 위치를 측정하기 위한 참조 신호를 전송하는 단계; 및상기 단말로부터, 상기 단말의 위치를 측정하기 위한 참조 신호에 기초하여, 상기 단말과 상기 기지국 사이에 가시 경로 채널 존재 여부 및 상기 단말의 위치 정보를 수신하는 단계;를 더 포함하고,상기 가시 경로 채널 존재 여부 및 상기 단말의 위치 정보는 상기 참조 신호에 기초하여 결정된, 방법.
- 제1항에 있어서,상기 다중 대역 각각에서 채널을 측정하기 위한 참조 신호를 전송하기 위한 자원은 상기 단말이 상기 다중 대역 각각에 대해 동시 상향 링크 전송이 가능한지 여부에 기초하여 결정되고,상기 단말이 다중 대역 각각에 대해 동시 상향 링크 전송이 가능한지 여부는 단말의 능력(capability) 정보에 기초하여 결정되는, 방법.
- 제1항에 있어서,상기 다중 대역은 기 설정된 주파수 차이보다 큰 값으로 분리된 적어도 두개의 주파수 대역을 포함하고,상기 기 설정된 주파수 차이는, 상기 각 다중 대역에 대한 경로 손실 지수, 섀도윙 값, 또는 각 다중 대역에 대한 반송파의 주파수 값 중 적어도 하나에 기초하여 결정되는, 방법.
- 무선 통신 시스템에서 단말이 가시 경로 채널을 식별하는 방법에 있어서,기지국으로부터, 다중 대역 각각에서 채널을 측정하기 위한 참조 신호를 수신하는 단계;상기 참조 신호에 기초하여, 상기 다중 대역 각각에 대해 상기 채널이 가시 경로(Line-of-Sight), 또는 비 가시 경로인지를 결정하는 단계;상기 다중 대역 각각에서 상기 채널이 가시 경로로 결정된 경우, 상기 채널을 상기 가시 경로 채널로 식별하는 단계; 및상기 기지국으로 상기 단말의 위치 정보, 상기 가시 경로 채널에 대한 식별 결과 정보, 또는 상기 가시 경로 채널의 특성에 기초하여 생성된 신호 중 적어도 하나를 전송하는 단계;를 포함하는, 방법.
- 제12항에 있어서,상기 기지국으로, 상기 다중 대역 각각에서 랜덤 엑세스 프리엠블을 전송하는 단계;를 더 포함하고,상기 기지국으로부터, 상기 다중 대역 각각에서 채널을 측정하기 위한 참조 신호를 수신하는 단계;는,상기 랜덤 액세스 프리엠블에 기초하여, 상기 다중 대역 중 적어도 하나의 대역에서 채널이 비 가시 경로로 결정된 경우, 상기 다중 대역 각각에서 채널을 측정하기 위한 참조 신호를 수신하는 단계;를 포함하는, 방법.
- 제12항에 있어서, 상기 참조 신호에 기초하여, 상기 다중 대역 각각에 대해 상기 채널이 가시 경로, 또는 비 가시 경로인지를 결정하는 단계;는,제1 주파수 대역에서 수신한 참조 신호의 채널 임펄스 응답에 기초하여 상기 제1 주파수 대역에서 수신한 참조 신호의 지연 전력 값을 결정하는 단계; 및제2 주파수 대역에서 수신한 참조 신호의 채널 임펄스 응답에 기초하여 상기 제2 주파수 대역에서 수신한 참조 신호의 지연 전력 값을 결정하는 단계;를 포함하고,상기 채널을 상기 가시 경로 채널로 식별하는 단계;는,상기 제1 주파수 대역에서 수신한 참조 신호의 지연 전력 값이 상기 제1 주파수 대역에 대해 결정된 문턱 전력 값보다 크고, 상기 제2 주파수 대역에서 수신한 참조 신호의 지연 전력 값이 상기 제2 주파수 대역에 대해 결정된 문턱 전력 값보다 큰 경우, 상기 채널을 상기 가시 경로 채널로 식별하는 단계;를 포함하는, 방법.
- 무선 통신 시스템에서 가시 경로 채널을 식별하는 기지국에 있어서,송수신부; 및프로세서를 포함하고,상기 프로세서는,단말로부터, 다중 대역 각각에서 채널을 측정하기 위한 참조 신호를 수신하도록 상기 송수신부를 제어하고,상기 참조 신호에 기초하여, 상기 다중 대역 각각에 대해 상기 채널이 가시 경로(Line-of-Sight), 또는 비 가시 경로인지를 결정하고,상기 다중 대역 각각에서 상기 채널이 가시 경로로 결정된 경우, 상기 채널을 상기 가시 경로 채널로 식별하고,상기 단말로 상기 단말의 위치 정보, 상기 가시 경로 채널에 대한 식별 결과 정보, 또는 상기 가시 경로 채널의 특성에 기초하여 생성된 신호 중 적어도 하나를 전송하도록 상기 송수신부를 제어하도록 구성된, 기지국.
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