KR20220013815A - Method and apparatus for channel estimation in communication network - Google Patents

Abstract

The present invention relates to a method for channel estimation in a communication network and a device thereof. An operating method of a terminal comprises a step of receiving a message including setup information for channel measurement from a base station, receiving a first reference signal from the base station on the basis of the setup information included in the message, determining a resource region to be used for transmission of a second reference signal based on a measurement result of the first reference signal, and transmitting information indicating a size of the resource region to the base station. Accordingly, performance of the communication network can be increased.

Description

METHOD AND APPARATUS FOR CHANNEL ESTIMATION IN COMMUNICATION NETWORK

The present invention relates to a channel estimation technique in a communication network, and more particularly, to a channel estimation technique based on a two-dimensional spread modulation scheme.

For processing of rapidly increasing wireless data, a frequency band (eg, a frequency band of 6 GHz or more) higher than a frequency band (eg, a frequency band of 6 GHz or less) of long term evolution (LTE) (or LTE-A) A communication network (eg, a new radio (NR) communication network) using The NR communication network may support a frequency band of 6 GHz or higher as well as a frequency band of 6 GHz or less, and may support various communication services and scenarios compared to an LTE communication network. For example, a usage scenario of the NR communication network may include enhanced Mobile BroadBand (eMBB), Ultra Reliable Low Latency Communication (URLLC), massive Machine Type Communication (mMTC), and the like.

On the other hand, when the radio channel environment is a multi-path and high-speed moving environment, the radio channel has both a frequency-selective characteristic and a time-selective characteristic, and thus the radio channel may continuously change according to time. Accordingly, the receiver may repeatedly perform channel estimation to increase the accuracy of channel estimation. In this case, when the receiver repeatedly performs channel estimation, a waste of resources for this may be large.

In order to reduce resource waste, the receiver may perform channel estimation only on some subcarriers (eg, a reference signal), and the other part may be estimated using interpolation. However, since such an interpolation method may not accurately estimate a channel, a method for more accurately estimating a channel may be required.

An object of the present invention to solve the above problems is to provide a method and apparatus for estimating a channel based on a reference signal in a communication network.

In the operating method of a terminal in a communication system according to a first embodiment for achieving the above object, receiving a message including configuration information for channel measurement from a base station, a first based on the configuration information included in the message Receiving a reference signal from the base station, determining a resource region to be used for transmission of a second reference signal based on a measurement result of the first reference signal, and transmitting information indicating the size of the resource region to the base station may include.

Here, the determining of the resource region includes performing a measurement operation on the first reference signal in the first sub measurement region among the entire measurement region, and when the measurement result of the first reference signal exceeds the first threshold, It may include determining the first sub-measurement region as a resource region.

Here, the determining of the resource region includes performing a measurement operation on the first reference signal in the first sub measurement region among the entire measurement region, and when the measurement result of the first reference signal is less than or equal to the first threshold, the entire measurement region performing a measurement operation on the first reference signal in a second sub measurement area larger than the first sub measurement area, and when a measurement result of the first reference signal in the second sub measurement area exceeds a first threshold , determining the second sub measurement region as the resource region.

Here, the method of operation of the terminal includes the steps of receiving control information including scheduling information from the base station, receiving data and a second reference signal from the base station based on the scheduling information, and resources based on the measurement result of the second reference signal The method may further include updating the region, and transmitting information indicating the updated resource region to the base station.

Here, the updating of the resource region includes: performing a measurement operation on the second reference signal in a third sub measurement region among the entire measurement region; and when the measurement result of the second reference signal is greater than or equal to the second threshold and less than or equal to the third threshold, maintaining the third sub measurement region as a resource region, wherein the second threshold is smaller than the third threshold may include

Here, the updating of the resource region includes: performing a measurement operation on the second reference signal in a third sub measurement region among the entire measurement region; When the measurement result of the second reference signal is less than the second threshold or exceeds the third threshold, the second reference signal is measured in the fourth sub measurement area having a size different from that of the third sub measurement area among the entire measurement area performing an action; and when the measurement result of the second reference signal in the fourth sub measurement region is greater than or equal to the second threshold and less than or equal to the third threshold, updating the fourth sub measurement region to the resource region, wherein the second threshold is 3 may include less than the threshold.

Here, the message may include a threshold value that is a reference for each measurement of the first reference signal and the second reference signal, and information indicating a measurement area in which each of the first reference signal and the second reference signal are measured. In addition, the message may be mapped to a plurality of transmission regions in a domain including a first axis indicating the Doppler effect and a second axis indicating propagation delay.

Here, the first transmission area among the plurality of transmission areas may be disposed to be spaced apart from the second transmission area in the first axis of the domain. Also, among the plurality of transmission areas, the first transmission area may be disposed to be spaced apart from the second transmission area on a second axis of the domain.

In the operating method of a base station in a communication system according to a second embodiment for achieving the above object, transmitting a message including configuration information for channel measurement to a terminal, a first method based on the configuration information included in the message Transmitting a reference signal to the terminal, and receiving information indicating a resource region determined based on the measurement result of the first reference signal from the terminal, the resource region can be used for transmission of the second reference signal have.

Here, the operating method of the base station includes the steps of transmitting control information including scheduling information to the terminal, transmitting data and a second reference signal to the terminal based on the scheduling information, the resource region updated based on the second reference signal It may further include the step of receiving the indicating information from the terminal.

Here, the message may include a threshold value that is a reference for each measurement of the first reference signal and the second reference signal, and information indicating a measurement area in which each of the first reference signal and the second reference signal are measured. In addition, the message may be mapped to a plurality of transmission transmission regions in a domain including a first axis indicating the Doppler effect and a second axis indicating a propagation delay.

Here, the first transmission area among the plurality of transmission areas may be disposed to be spaced apart from the second transmission area in the first axis of the domain. Also, among the plurality of transmission areas, the first transmission area may be disposed to be spaced apart from the second transmission area on a second axis of the domain.

A terminal in a communication system according to a third embodiment for achieving the above object, comprising a processor, a memory in electronic communication with the processor, and instructions stored in the memory, and when the instructions are executed by the processor, the instructions are Receives a message including configuration information for channel measurement from the base station, receives a first reference signal from the base station based on configuration information included in the message, and receives a second reference signal based on the measurement result of the first reference signal Determine a resource region to be used for signal transmission, and may operate to cause transmission of information indicating the determined resource region to the base station.

Here, when determining the resource region, the commands indicate that the UE performs a measurement operation on the first reference signal in the first sub measurement region among the entire measurement region, and the measurement result of the first reference signal exceeds the first threshold In this case, it may operate to cause determination of the first sub-measurement region as a resource region.

Here, when determining the resource region, the commands are when the UE performs a measurement operation on the first reference signal in the first sub measurement region among the entire measurement region, and when the measurement result of the first reference signal is less than or equal to the first threshold , a measurement operation is performed on the first reference signal in a second sub measurement area that is larger than the first sub measurement area among the entire measurement area, and the measurement result of the first reference signal in the second sub measurement area determines the first threshold value If it exceeds, it may operate to cause determination of the second sub-measurement region as the resource region.

Here, the commands allow the terminal to receive control information including scheduling information from the base station, receive data from the base station based on the second reference signal and the scheduling information, update the resource region based on the measurement result of the second reference signal, and , and may operate to cause transmission of information indicating the updated resource region to the base station.

According to the present invention, the communication node allocates resources for reference signal transmission for channel estimation or resource allocation to data symbols depending on the case where the delay spread and the Doppler spread are large and the delay spread and the Doppler spread are small in the wireless channel environment. can be different Accordingly, both channel accuracy and resource use efficiency may be improved.

For example, when the delay spread and Doppler spread in the radio channel environment are large, the communication node may allocate many resources to channel estimation. Due to this, the accuracy of channel estimation can be improved. The communication node may allocate a large number of resources for data transmission when the delay spread and the Doppler spread in the radio channel environment are small. Due to this, resource use efficiency may be improved. can

However, it is not limited only to the above-described technical effects, and the scope of the present invention may be extended to other technical effects that can be inferred by those skilled in the art based on the entire contents of the present specification.

1 is a conceptual diagram illustrating a first embodiment of a communication network.
2 is a block diagram of communication nodes constituting a communication network.
3 is a flowchart illustrating a channel estimation method in a communication network.
4 is a conceptual diagram illustrating a process in which resource regions are mapped in a communication network.
5 is a flowchart illustrating a method of determining a resource area of a communication network.
6 is a flowchart illustrating a method of updating a resource area of a communication network.
7 is a conceptual diagram illustrating a resource area in a communication network.
8 is a conceptual diagram illustrating a resource region of a reference signal of a communication network.
9 is a graph illustrating a symbol error rate according to a ratio of a resource area allocated to channel estimation in a communication network.

Since the present invention can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to specific embodiments, and it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms such as first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component. and/or includes a combination of a plurality of related listed items or any of a plurality of related listed items.

When an element is referred to as being “connected” or “connected” to another element, it is understood that it may be directly connected or connected to the other element, but other elements may exist in between. it should be On the other hand, when it is said that a certain element is "directly connected" or "directly connected" to another element, it should be understood that the other element does not exist in the middle.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. does not

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. In describing the present invention, in order to facilitate the overall understanding, the same reference numerals are used for the same components in the drawings, and duplicate descriptions of the same components are omitted.

A communication network to which embodiments according to the present invention are applied will be described. The communication system may be a 4G communication network (eg, a long-term evolution (LTE) communication network), a 5G communication network (eg, a new radio (NR) communication network), and the like. A 4G communication network and a 5G communication network may be classified as a terrestrial network.

The communication network may operate based on LTE technology and/or NR technology. The communication network may support communication not only in a frequency band of 6 GHz or less, but also in a frequency band of 6 GHz or more. A 4G communication network can support communication in a frequency band of 6 GHz or less. A 5G communication network can support communication in a frequency band of 6 GHz or higher as well as a frequency band of 6 GHz or less. A communication network to which embodiments according to the present invention are applied is not limited to the content described below, and embodiments according to the present invention may be applied to various communication networks. Here, a communication network may be used in the same sense as a communication system.

1 is a conceptual diagram illustrating a first embodiment of a communication system.

1, the communication system 100 is a plurality of communication nodes (110-1, 110-2, 110-3, 120-1, 120-2, 130-1, 130-2, 130-3, 130-4, 130-5, 130-6). In addition, the communication system 100 is a core network (core network) (eg, S-GW (serving-gateway), P-GW (packet data network (PDN)-gateway), MME (mobility management entity)) may include more. When the communication system 100 is a 5G communication system (eg, a new radio (NR) system), the core network is an access and mobility management function (AMF), a user plane function (UPF), a session management function (SMF), etc. may include

The plurality of communication nodes 110 to 130 may support a communication protocol (eg, an LTE communication protocol, an LTE-A communication protocol, an NR communication protocol, etc.) defined in a 3rd generation partnership project (3GPP) standard. A plurality of communication nodes 110 to 130 are CDMA (code division multiple access) technology, WCDMA (wideband CDMA) technology, TDMA (time division multiple access) technology, FDMA (frequency division multiple access) technology, OFDM (orthogonal frequency division) technology multiplexing) technology, Filtered OFDM technology, CP (cyclic prefix)-OFDM technology, DFT-s-OFDM (discrete Fourier transform-spread-OFDM) technology, OFDMA (orthogonal frequency division multiple access) technology, SC (single carrier)-FDMA Technology, Non-orthogonal Multiple Access (NOMA) technology, GFDM (generalized frequency division multiplexing) technology, FBMC (filter bank multi-carrier) technology, UFMC (universal filtered multi-carrier) technology, SDMA (Space Division Multiple Access) technology, etc. can support Each of the plurality of communication nodes may have the following structure.

2 is a block diagram showing a first embodiment of a communication node constituting a communication system.

Referring to FIG. 2 , the communication node 200 may include at least one processor 210 , a memory 220 , and a transceiver 230 connected to a network to perform communication. In addition, the communication node 200 may further include an input interface device 240 , an output interface device 250 , a storage device 260 , and the like. Each of the components included in the communication node 200 may be connected by a bus 270 to communicate with each other.

However, each of the components included in the communication node 200 may not be connected to the common bus 270 but to the processor 210 through an individual interface or an individual bus. For example, the processor 210 may be connected to at least one of the memory 220 , the transceiver 230 , the input interface device 240 , the output interface device 250 , and the storage device 260 through a dedicated interface. .

The processor 210 may execute a program command stored in at least one of the memory 220 and the storage device 260 . The processor 210 may mean a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which methods according to embodiments of the present invention are performed. Each of the memory 220 and the storage device 260 may be configured as at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory 220 may be configured as at least one of a read only memory (ROM) and a random access memory (RAM).

Referring back to FIG. 1 , the communication system 100 includes a plurality of base stations 110 - 1 , 110 - 2 , 110 - 3 , 120 - 1 and 120 - 2 , and a plurality of terminals 130 - 1, 130-2, 130-3, 130-4, 130-5, 130-6). Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 may form a macro cell. Each of the fourth base station 120-1 and the fifth base station 120-2 may form a small cell. The fourth base station 120-1, the third terminal 130-3, and the fourth terminal 130-4 may belong to the cell coverage of the first base station 110-1. The second terminal 130-2, the fourth terminal 130-4, and the fifth terminal 130-5 may belong to the cell coverage of the second base station 110-2. The fifth base station 120-2, the fourth terminal 130-4, the fifth terminal 130-5, and the sixth terminal 130-6 may belong to the cell coverage of the third base station 110-3. have. The first terminal 130-1 may belong to the cell coverage of the fourth base station 120-1. The sixth terminal 130-6 may belong to the cell coverage of the fifth base station 120-2.

Here, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 is a NodeB (NB), an evolved NodeB (eNB), gNB, an advanced base station (ABS), HR - BS (high reliability-base station), BTS (base transceiver station), radio base station (radio base station), radio transceiver (radio transceiver), access point (access point), access node (node), RAS (radio access station) ), MMR-BS (mobile multihop relay-base station), RS (relay station), ARS (advanced relay station), HR-RS (high reliability-relay station), HNB (home NodeB), HeNB (home eNodeB), It may be referred to as a road side unit (RSU), a radio remote head (RRH), a transmission point (TP), a transmission and reception point (TRP), and the like.

Each of the plurality of terminals 130-1, 130-2, 130-3, 130-4, 130-5, 130-6 includes a user equipment (UE), a terminal equipment (TE), an advanced mobile station (AMS), HR-MS (high reliability-mobile station), terminal, access terminal, mobile terminal, station, subscriber station, mobile station, portable It may be referred to as a portable subscriber station, a node, a device, an on board unit (OBU), and the like.

Meanwhile, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may operate in different frequency bands or may operate in the same frequency band. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be connected to each other through an ideal backhaul link or a non-ideal backhaul link. , information can be exchanged with each other through an ideal backhaul link or a non-ideal backhaul link. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be connected to the core network through an ideal backhaul link or a non-ideal backhaul link. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 transmits a signal received from the core network to the corresponding terminals 130-1, 130-2, 130-3, 130 -4, 130-5, 130-6), and a signal received from the corresponding terminal (130-1, 130-2, 130-3, 130-4, 130-5, 130-6) is transmitted to the core network can be sent to

In addition, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 transmits MIMO (eg, single user (SU)-MIMO, multi user (MU)- MIMO, massive MIMO, etc.), coordinated multipoint (CoMP) transmission, carrier aggregation (CA) transmission, transmission in an unlicensed band, direct communication between terminals (device to device communication, D2D) (or , Proximity Services (ProSe)), Internet of Things (IoT) communication, dual connectivity (DC), and the like may be supported. Here, each of the plurality of terminals 130-1, 130-2, 130-3, 130-4, 130-5, 130-6 is the base station 110-1, 110-2, 110-3, and 120-1. , 120-2) and corresponding operations, and operations supported by the base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be performed. For example, the second base station 110-2 may transmit a signal to the fourth terminal 130-4 based on the SU-MIMO method, and the fourth terminal 130-4 may transmit a signal based on the SU-MIMO method. A signal may be received from the second base station 110 - 2 . Alternatively, the second base station 110 - 2 may transmit a signal to the fourth terminal 130 - 4 and the fifth terminal 130 - 5 based on the MU-MIMO scheme, and the fourth terminal 130 - 4 . and each of the fifth terminals 130 - 5 may receive a signal from the second base station 110 - 2 by the MU-MIMO method.

Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 may transmit a signal to the fourth terminal 130-4 based on the CoMP scheme, and the fourth The terminal 130-4 may receive signals from the first base station 110-1, the second base station 110-2, and the third base station 110-3 by the CoMP method. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 is a terminal 130-1, 130-2, 130-3, 130-4 belonging to its own cell coverage. , 130-5, 130-6) and the CA method can transmit and receive signals. Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 controls D2D between the fourth terminal 130-4 and the fifth terminal 130-5. and each of the fourth terminal 130-4 and the fifth terminal 130-5 may perform D2D under the control of the second base station 110-2 and the third base station 110-3, respectively. .

Meanwhile, the communication system may support three types of frame structures. The type 1 frame structure may be applied to a frequency division duplex (FDD) communication system, the type 2 frame structure may be applied to a time division duplex (TDD) communication system, and the type 3 frame structure may be applied to an unlicensed band-based communication system (eg, For example, it may be applied to a licensed assisted access (LAA) communication system.

In a wireless communication system, data is easily distorted and altered during transmission. To overcome the radio channel environment, the receiver (terminal) estimates the radio channel, and based on this, channel equalization (estimation, interpolation) is performed to remove the influence of the radio channel from the received signal distorted by the radio channel, and the transmitter transmits find a signal. The accuracy of channel estimation performed by the receiver (terminal) is very important. If the channel estimation result of the terminal is inaccurate, the original signal transmitted by the base station cannot be detected from the received signal from which the distortion of the radio channel is removed through channel equalization.

In a wireless communication system, accuracy of channel estimation performed by a receiver is important. In particular, when the radio channel environment is a high-speed moving environment as well as a multi-path environment, the radio channel has both a frequency-selective characteristic and a time-selective characteristic, and the radio channel continuously changes with time. will be performed frequently. If the receiver performs channel estimation several times, a corresponding resource may be consumed a lot.

Accordingly, the receiver may perform channel estimation on only some subcarriers (data) in order to reduce resource waste, and estimate the remaining data using interpolation. However, since such an interpolation method may not accurately estimate the channel, a method for increasing the accuracy of the channel estimation is required.

When the radio channel environment has frequency selective characteristics due to multipath, the existing orthogonal frequency division multiplexing (OFDM) used in wireless LAN and cellular communication using a strong modulation method performs channel estimation in units of subcarriers, and this channel The distortion of the radio channel is removed from the received signal through channel equalization using estimation.

However, when the radio channel environment is a multi-path and high-speed moving environment, the radio channel has both frequency-selective and time-selective characteristics. Since the radio channel state continuously changes with time, in order to increase the accuracy of the channel estimation, it is necessary to frequently perform the channel estimation, resulting in a large waste of resources. In order to reduce resource waste, channel estimation is performed on only some subcarriers without performing channel estimation on all subcarriers of OFDM, and there is a method of frequently estimating channels in time. For data in a time period in which estimation and direct channel estimation are not performed, since the UE must perform channel estimation using interpolation, the channel estimation operation may not be accurate.

As described above, when the radio channel environment is a frequency-selective and time-selective environment, many waveforms have been proposed to increase the accuracy of channel estimation. A method of two-dimensionally spreading a symbol along a time-frequency domain may be proposed. This may include a method of spreading each data symbol occupying a specific resource region to all or a part of the resource region. Each of the spread data symbols may include all the channel characteristics of the spread region, and since all data symbols have almost similar channel characteristics, the channel characteristics are hardly changed from the viewpoint of the resource region after 2D spreading. When channel estimation is performed in a two-dimensional spread resource region, even if channel estimation is performed in some resource regions, the remaining resource regions can assume the same channel estimation. Channel estimation for the entire resource region may be performed without using an additional technique such as interpolation to perform the estimation.

When the radio channel environment is a frequency-selective and time-selective environment, data symbols are separated by time and frequency axes so that a receiver (eg, a terminal) of a communication system can effectively detect a signal sent from a transmitter (eg, a base station). Accordingly, a modulation method that spreads two-dimensionally using a specific permutation may be used.

Since each of the two-dimensionally spread signals in the time-frequency domain experiences almost the same channel regardless of the frequency-selective and time-selective characteristics of the radio channel, after channel estimation is performed for some spreading resource regions, the same is true for the remaining resource regions as well. The accuracy of the channel estimation can be sufficiently increased by using a method that assumes the channel estimation. In this way, resource efficiency can be increased by allocating resources allocated for channel estimation to actual transmission signals.

There are several methods for spreading a symbol in two dimensions in the time-frequency domain. In this case, when a Fourier permutation is used as a spreading permutation used for two-dimensional spreading, the symbol allocation or mapping before spreading corresponding to the time-frequency domain is used. The mapping region may be a Doppler-delay region. In the case of a Doppler-delay region reception signal, a two-dimensional convolutional relationship between a transmission signal in the diffusion region and a channel in the diffusion region may be established.

Another example in which a received signal can be expressed as a convolutional relationship between a transmission signal and a channel is a one-dimensional time domain communication system. The time domain reception signal is a one-dimensional convolutional relationship between the time domain transmission signal and the time domain channel impulse response, and if the transmission signal is set as an impulse, the signal received by the receiver is a channel impulse response and a channel estimation result.

In a similar manner, in the case of transmitting a 2D impulse in the Doppler-delay region in the 2D spread modulation method from the transmitter (base station), the received signal becomes a 2D impulse response of the channel, which is the channel estimation result.

However, if all the resources of the Doppler-delay region are allocated to the two-dimensional impulse for channel estimation every time as above, the accuracy of the channel estimation is almost perfect, but all the resources of the existing wireless communication system are allocated to the reference signal. , there is no resource for data transmission, so the resource utilization efficiency becomes 0.

Conversely, in order to increase resource use efficiency, a small number of resources may be allocated to a two-dimensional impulse for channel estimation, and data symbols may be allocated to the remaining resources. In a multi-path environment with a very large delay spread and a high-speed moving environment with a very large Doppler spread in the wireless channel environment, interference from data symbols invades the resource area allocated for channel estimation due to the convolutional characteristics of signals and channels, resulting in channel estimation. can distort

The terminal and the base station according to the embodiments optimally allocate a region for channel estimation and a region for data symbols when allocating a transmission signal resource in a delay-Doppler region in a two-dimensional spread modulation method using a Fourier permutation. can do. In addition, an operating method and apparatus for increasing the efficiency of resource use while increasing the accuracy of channel estimation will be described in the embodiment.

The terminal and the base station according to the embodiments may determine the range and location of the two-dimensional channel impulse response in the delay-Doppler region in consideration of the delay spread due to the multi-path environment of the radio channel and the Doppler spread due to the high-speed movement environment. .

The terminal and the base station receive the characteristic information of the radio channel environment and use this information to determine a delay-Doppler resource region for channel estimation using a two-dimensional spread modulation method using a Fourier permutation and a delay-Doppler resource region for a data symbol. have.

The terminal and the base station according to the embodiments define resource regions for the first reference signal, the configuration information included in the message, and the second reference signal, extract the characteristics of the radio channel environment through this, and perform channel estimation to obtain scheduling information It is possible to perform a resource region allocation procedure for data and a second reference signal based on .

According to embodiments, the terminal and the base station define configuration information for controlling the reference signal resource region determination procedure and threshold values included therein, and the terminal receives the first reference signal for channel measurement of the wireless communication system and receives the first 2 It is possible to perform the resource region allocation procedure (the operation of determining the resource region) of the reference signal and transmit the resource region indication information to the base station.

Also, the receiver (terminal) according to the embodiments may update the resource region of the second reference signal through continuous monitoring during communication. The terminal transmits the sub measurement area measurement result and information on maintenance or update according to the threshold to the base station, and can perform the resource reallocation procedure (update procedure) even in a situation where the radio channel environment changes during communication. Accuracy and resource utilization efficiency can be maintained at or above a set level.

Next, as to a channel estimation technique in a communication system, a method and apparatus for determining or updating a reference signal resource region for channel estimation in a delay-Doppler resource region in a two-dimensional spread modulation delay-based system will be described. Even when a method (eg, transmission or reception of a signal) performed in a first communication node among communication nodes is described, a corresponding second communication node is a method (eg, a method corresponding to the method performed in the first communication node) For example, reception or transmission of a signal) may be performed. That is, when the operation of the terminal is described, the corresponding base station may perform the operation corresponding to the operation of the terminal. Conversely, when the operation of the base station is described, the corresponding terminal may perform the operation corresponding to the operation of the base station.

3 is a flowchart for determining or updating a resource region for channel estimation in a communication network according to embodiments. The method for the UE to determine or update the resource region in FIG. 3 is a simplified reconfiguration focusing on procedures necessary to explain the embodiments of the present invention, and detailed procedures or subsequent procedures may be omitted.

Referring to FIG. 3 , the base station 320 may transmit a message including configuration information for channel measurement to the terminal 310 ( S301 ). The terminal 310 may receive a message including configuration information for channel measurement from the base station 320 (S301). Here, the base station 320 may mean a serving base station, a source base station, a serving cell, or a source cell.

The configuration information may include an indicator for requesting channel measurement, and the message including the configuration information may be control information. The base station 320 transmits the message to system information, a radio resource control (RRC) message, a medium access control (MAC) message (eg, a MAC control element (CE), and a physical (PHY) message (eg, DCI ( downlink control information)) may be transmitted to the terminal 310 through any one or more combinations.

The configuration information is to determine the resource region information of the first reference signal (eg, the location or size of the resource region in which the initial reference signal is transmitted), the resource region of the reference signal (eg, the position or size of the resource region) It may include one or more of information indicating an increase/decrease range of a resource region of a reference signal and a threshold value(s) set for the reference signal. In a message including configuration information, a resource region may be defined as follows.

4 is a conceptual diagram illustrating a resource region in which a message including configuration information is matched in a communication network.

Referring to FIG. 4 , when the base station transmits a message including configuration information for channel measurement to the terminal, an example of mapping the message to the delay-Doppler domain is shown. That is, the message including the configuration information may be transmitted in the resource region(s) in the delay-Doppler domain.

In a domain composed of a first axis (x-axis) indicating the Doppler effect and a second axis (y-axis) indicating propagation delay, the base station maps the message to a plurality of transmission areas 410, 420, 430 to the terminal can be sent to

Control resource regions 410, 420, and 430 for control information (ie, configuration information) of FIGS. 4(a) to 4(c) are located outside the delay-Doppler domain so as not to interfere with channel estimation. Indicates the structure to which the control resource area is allocated. The remaining resource regions indicate structures allocated to reference signal resource regions 411 , 421 , and 431 for channel estimation. That is, the control resource regions 410, 420, 430 may be disposed in the outer resource region in the delay-Doppler domain, and the reference signal resource regions 411, 421, 431 are in the inner resource region in the delay-Doppler domain. can be placed.

In FIG. 4A , the plurality of control regions 410 may be disposed to be spaced apart from each other in the first axis of the delay-Doppler domain. For example, one control area 410 may be disposed in an upper area in the first axis, and the other control areas 410 may be disposed in a lower area in the first axis. In FIG. 4B , the plurality of control regions 420 may be disposed to be spaced apart from each other in the second axis of the delay-Doppler domain. For example, one control area 420 may be disposed in an upper area in the second axis, and the other control area 420 may be disposed in a lower area in the second axis. Also, a combination of the plurality of control areas 410 illustrated in FIG. 4A and the plurality of control areas 420 illustrated in FIG. 4B may be used. That is, in FIG. 4C , the plurality of control regions 430 includes two control regions 430 disposed in the upper region and lower region of the first axis and two control regions 430 disposed in the second upper region and lower region of the first axis. regions 430 .

Referring back to FIG. 3 , the base station 320 may generate a first reference signal based on the configuration information included in the message ( S303 ). The base station 320 may transmit a first reference signal to the terminal 310 (S305). The first reference signal may be transmitted through the resource region indicated by the configuration information. The terminal 310 may receive the first reference signal from the base station 320 based on the configuration information (eg, the resource area indicated by the configuration information) included in the message (S305).

The reference signal may be a cell-specific reference signal (CRS), a channel state information-reference signal (CSI-RS), a phase tracking-reference signal (PT-RS), and/or a demodulation-reference signal (DM-RS). The DM-RS or CSI-RS may be transmitted through a physical downlink control channel (PDCCH) channel.

The CSI-RS may be used by UEs to obtain necessary channel state information (CSI). For example, the UE may estimate channel state information (CSI) necessary for downlink scheduling, link adaptation, multi-antenna transmission configuration, and the like, based on the measurement result of the CSI-RS. The CSI-RS may be a reference signal for obtaining channel state information, and the DM-RS may be a reference signal for channel estimation.

The terminal 310 may determine a resource region to be used for transmission of the second reference signal based on the measurement result of the first reference signal (S307).

FIG. 5 is an illustration of a flowchart regarding the step of determining a resource region of a communication network according to the embodiments in FIG. 3 .

Referring to FIG. 5 , the terminal 310 may perform a measurement operation on the first reference signal in the first sub measurement region (S307-1). The first sub measurement area may be indicated by the setting information received in step S301. The terminal 310 may determine whether the measurement result of the first reference signal exceeds a first threshold (S307-2). Here, the first threshold value may be included in the setting information included in the message received in step S301. Alternatively, the first threshold may be predefined in a technical standard.

The terminal 310 may determine that the measurement result of the first reference signal exceeds the first threshold. In this case, the terminal 310 may determine the first sub-measurement region as the resource region (S307-3).

Alternatively, the terminal 310 may determine that the measurement result of the first reference signal does not exceed the first threshold. In this case, the UE may perform a measurement operation on the first reference signal in the second sub measurement region (S307-4). The second sub measurement area may be indicated by the setting information received in step S301. For example, the terminal 310 may increase or decrease the first sub-measurement area according to the increase/decrease range (eg, increase/decrease rate) indicated by the configuration information, and increase or decrease the first sub-measurement area. may be determined as the second sub measurement area.

Specifically, the UE may set a second sub-measurement region larger than the first sub-measurement region among the entire measurement region. The terminal 310 may determine whether the measurement result of the first reference signal exceeds the first threshold in the second sub measurement region (S307-5). The terminal 310 may determine that the measurement result of the first reference signal in the second sub measurement region exceeds the first threshold. In this case, the terminal 310 may determine the second sub-measurement region as the resource region (S307-6).

The terminal 310 may determine that the measurement result of the first reference signal in the second sub measurement region does not exceed the first threshold. In this case, the terminal 310 may again perform a measurement operation on the first reference signal in the third sub-measurement region (S307-4). The third sub measurement area may be indicated by the setting information received in step S301. For example, the terminal 310 may increase or decrease the second sub-measurement area according to the increase/decrease range (eg, increase/decrease rate) indicated by the configuration information, and increase or decrease the second sub-measurement area. may be determined as the third sub-measurement area. Specifically, the UE may set a third sub-measurement region larger than the second sub-measurement region among the entire measurement region.

Referring back to FIG. 3 , the terminal 310 may determine the second sub-measurement region as the resource region ( S307 ), and information indicating the resource region (eg, time and frequency resource for transmitting a reference signal) information, an antenna port for a reference signal) may be transmitted to the base station 320 . The base station 320 may receive information indicating the determined resource region from the terminal 310 (S309). The base station 320 may determine a resource region in which the reference signal is transmitted based on the information obtained from the terminal 310 .

Meanwhile, the base station 320 may generate control information (eg, DCI) including scheduling information and transmit the generated control information to the terminal 310 ( S311 ). The terminal 310 may receive control information including scheduling information from the base station (S311). Alternatively, when a resource to which data is transmitted is preset by semi-persistent scheduling (SPS), step S311 may be omitted. The base station 320 may generate data and a second reference signal based on the scheduling information, and may transmit the data and the second reference signal to the terminal 310 (S313). A resource to which the second reference signal is mapped (eg, a resource element in the PDSCH) may be a resource indicated by the information received in step S309. The terminal 310 may receive data and a second reference signal from the base station based on the scheduling information (S313). For example, the terminal 310 may receive data and a second reference signal by performing a monitoring operation on a resource (eg, PDSCH) indicated by the scheduling information, and a specific resource (eg, PDSCH) in the PDSCH. A second reference signal may be obtained from the resource determined by the terminal in step S307). A resource region in which data and the second reference signal are transmitted may be as follows. 7 is a conceptual diagram illustrating a resource region in a communication network.

Referring to FIG. 7 , a terminal (eg, a receiver) may receive DCI from a base station (eg, a transmitter) through a PDCCH. The terminal may receive data and a second reference signal from the base station through the PDSCH channel based on the scheduling information included in the received control information.

The data region 710 in the delay-Doppler domain of FIG. 7 shows an example of a resource region for the base station to transmit data to the terminal. The diagram shows an example in which the data region 710 is allocated in the delay-Doppler domain for efficient use of resources in the base station. The resource region 720 for the second reference signal can be allocated to a minimum. The second reference signal resource region 720 may be a resource region of a reference signal for the UE to estimate a channel in a two-dimensional spreading region. In the resource region for the base station to transmit data to the terminal, the second reference signal resource region 720 may be smaller than the data region 710 .

The second reference signal resource region 720 may be a resource region determined by the UE for transmission of the second reference signal based on the channel estimation measurement result of the first reference signal. After confirming in advance the location and size of the optimal reference signal resource region in the radio channel environment, the transmitter and the receiver share allocation information of the data region and the reference signal resource region to transmit data.

Next, as an example of determining the size of the resource region of the second reference signal, it will be described with reference to FIG. 8(a). FIG. 8(a) is a conceptual diagram illustrating a step S307 of FIG. 3 and a step of determining a resource region of a reference signal of the communication network of FIG. 5 .

The terminal may receive a message including configuration information for channel measurement from the base station. The terminal determines the size of the resource region in which the second reference signal is to be transmitted according to the first reference signal (eg, measuring the radio channel impulse response) measured based on information (threshold value, etc.) included in the configuration information; or Information such as location may be transmitted to the base station.

The base station may receive information indicating the resource region received from the terminal (eg, S309 of FIG. 3 ). Thereafter, the base station may transmit control information including scheduling information (eg, S311 of FIG. 3 ) to the terminal. The base station may transmit data and a second reference signal to the terminal based on the scheduling information. The terminal may demodulate data by performing radio channel estimation and radio channel compensation using the received second reference signal.

The UE may continuously monitor the resource region of the configured second reference signal (eg, continuously monitor the channel impulse response value for the resource region). When it is determined that the channel state has changed as a result of monitoring, the terminal may update the resource region of the second reference signal preset in the base station, and may transmit information indicating the updated resource region. The terminal according to the embodiments may measure the resource region (eg, the third sub-measurement region) of the preset reference signal and be included in the threshold range (second, third threshold value range) set according to the channel state. Information on updating the resource region, or update information according to various embodiments without being limited thereto, and information on time-frequency resources instructing to update by an arrangement method may be transmitted to the base station.

Referring to FIG. 8A , the UE may perform a measurement operation on the first reference signal in an initially set first sub measurement region 821 among all measurement regions 810 of the delay-Doppler domain of the graph. If it is determined that the measurement result of the first reference signal is less than or equal to the first threshold, the terminal may measure the first reference signal in the second sub measurement area 820 that is larger than the first sub measurement area. If the UE determines that the measurement result of the first reference signal in the initial sub measurement region is less than or equal to the threshold, the UE may perform a process of re-measuring by resetting a larger measurement region.

The first threshold value may be included in the setting information obtained in step S301.

When the measurement result of the first reference signal in the reset second sub measurement region 820 exceeds the first threshold, the UE uses the second sub measurement region 820 as a resource to be used for transmission of the second reference signal. area can be determined.

Next, as an example of updating the size of the resource region of the second reference signal, it will be described with reference to FIG. 8(b). FIG. 8(b) is a conceptual diagram illustrating steps S315 of FIG. 3 and updating of a resource region of a reference signal of the communication network of FIG. 6 .

In FIG. 3 , the terminal 310 may determine to update the resource region based on the measurement result of the second reference signal ( S315 ). Referring to FIG. 8(b) , a method of updating a resource region may be as follows.

The terminal 310 may perform a measurement operation on the second reference signal in the third sub measurement region among the entire measurement region (S315-1). The third sub measurement area may be indicated by the message received in step S301. For example, the third sub-measurement region may be the sub-measurement region 840 illustrated in FIG. 8B . The terminal 310 may determine whether the measurement result of the second reference signal is greater than or equal to the second threshold and less than or equal to the third threshold (S315-2). The terminal 310 may determine that the measurement result of the second reference signal is greater than or equal to the second threshold and less than or equal to the third threshold. In this case, the terminal 310 may maintain the third sub-measurement region as a resource region (S315-3). Here, the second threshold value may be smaller than the third threshold value. The second threshold and the third threshold may be indicated by the message received in step S301.

The terminal 310 may determine that the measurement result of the second reference signal is greater than or equal to the second threshold and not less than or equal to the third threshold. In this case, the terminal 310 may perform a measurement operation on the second reference signal in the fourth sub-measurement region having a size different from that of the third sub-measurement region (S315-4). Referring to FIG. 8B , the fourth sub-measurement area may be larger or smaller than the third sub-measurement area. For example, when the measurement result of the second reference signal exceeds the third threshold, the size of the fourth sub measurement region 750 may be smaller than the size of the third sub measurement region 740 . When the measurement result of the second reference signal is less than the second threshold, the size 730 of the fourth sub measurement region may be larger than the size of the third sub measurement region 740 . The fourth sub measurement area may be indicated by the message received in step S301. For example, the fourth sub-measurement region is an initially set sub-measurement region (eg, the third sub-measurement region 740) according to the increase/decrease range (eg, increase/decrease rate) indicated by the message received in step S301 . ) may be an increased or decreased fourth sub-measurement area. The increased fourth sub-measurement area may be the sub-measurement area 730 in FIG. 8(b) , and the reduced fourth sub-measurement area may be the sub-measurement area 750 in FIG. 8(b) .

The terminal 310 may determine that the measurement result of the second reference signal in the fourth sub measurement region is greater than or equal to the second threshold and less than or equal to the third threshold (S315-5). In this case, the terminal 310 may update the resource region as the fourth sub measurement region (S315-6). That is, when the measurement result of the reselected sub-measurement region is within the threshold range, the terminal 310 may update the sub-measurement region as the resource region of the reference signal.

As another embodiment of the operation of the terminal for determining the size of the resource region of FIG. 3 ( S307 ), the terminal 310 determines that the measurement result of the second reference signal in the fourth sub measurement region is less than the second threshold It can be done (S315-7). In this case, the terminal 310 may again perform a measurement operation on the second reference signal in another fourth sub-measurement region (by selecting a larger fourth sub-measurement region as the fifth sub-measurement region) ( not shown). The determination method of the fifth sub measurement area may be the same as the determination method of the above-described fourth sub measurement area. The terminal 310 may determine that the measurement result of the second reference signal in the fourth sub measurement region exceeds the third threshold (S315-8). In this case, the terminal 310 maintains the fourth sub-measurement region as the resource region of the second reference signal according to a preset setting (S315-9), or the second reference signal in a sub-measurement region smaller than the fourth sub-measurement region. A measurement operation may be performed for (not shown).

9 is a graph illustrating a symbol error rate according to a ratio of a resource area allocated to channel estimation in a communication network. Referring to FIG. 9 , when delay spread and Doppler spread in a radio channel environment are large, a terminal and a base station may allocate relatively many resources for channel estimation. Accordingly, the accuracy of channel estimation can be increased. When the delay spread and the Doppler spread in the radio channel environment are small, the terminal and the base station may allocate a relatively large number of resources for data transmission. Accordingly, resource use efficiency may be increased.

When the delay and Doppler spread of the wireless channel are small, if the terminal and the base station allocate a lot of resources for channel estimation, the performance indicators of the wireless communication system, such as FER (Frame Error Rate) or SER (Symbol Error Rate), are not improved. Usage efficiency may decrease. When the delay and Doppler spread of the radio channel are large, if the terminal and the base station allocate relatively few resources to the channel estimation, the resources allocated to the channel estimation may not reflect the actual channel impulse response. In addition, since information transmitted through a reference signal resource may be distorted due to interference of data transmitted to neighboring data symbols, a measurement result for channel estimation may be inaccurate. Therefore, FER or SER performance may deteriorate.

The graph of FIG. 9 shows that the root-mean-square (RMS) value of the delay spread of the wireless channel is 100 ns in the Tapped Delay Line (TDL)-A channel model environment of the 3rd Generation Partnership Project (3GPP), the carrier frequency is 4 GHz, and the It is a graph showing the SER performance according to the ratio of the resource area allocated to the channel estimation in an environment where the speed is 120 km/h.

Specifically, FIG. 9 is a graph in which the terminal and the base station increase the ratio of the reference signal resource region from 25% to 56%, and SER and SNR measurements from 901 to 909 are graphs. As shown in FIG. 9 , it can be confirmed that the SER performance is not significantly improved even when the UE increases the resources allocated for channel estimation.

Also, as shown in FIG. 9 , it indicates that the SER value or SNR value is not significantly improved even when the reference signal resource ratio of 907 is increased from the reference signal resource ratio of 907 (44%) to the reference signal resource ratio of 909 (56%). The point indicated by this 909 (if the reference signal resource is 56%) may be the ratio of the reference signal resource region to the total resource region reflecting the channel estimation suitable for the current radio channel state.

At point 909, it is shown that there is little change in the SER value or the SNR value even when the UE allocates more resources for channel estimation. Even if the UE adds resource allocation, the channel estimation accuracy may not increase. Accordingly, at this point, a method of increasing resource use efficiency may be performed.

In a wireless communication system using a two-dimensional spread modulation method using Fourier permutation, the efficiency of resource use in a given wireless channel environment can be maximized while maintaining the performance of the wireless communication system above a certain level in any wireless channel environment through the channel estimation procedure. .

A method of operating a terminal for determining and updating a resource region according to embodiments is a method of operating a terminal for determining and updating a resource region described with reference to FIGS. 3, 5, and 6 (eg, FIG. 3 of S307 and S315) may be included. A detailed description of one or more methods/operations described with reference to FIGS. 3, 5, and 6 will be omitted.

The methods according to the present invention may be implemented in the form of program instructions that can be executed by various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, etc. alone or in combination. The program instructions recorded on the computer-readable medium may be specially designed and configured for the present invention, or may be known and available to those skilled in the art of computer software.

Examples of computer-readable media include hardware devices specially configured to store and carry out program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine language codes such as those generated by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. The hardware device described above may be configured to operate as at least one software module to perform the operations of the present invention, and vice versa.

Although it has been described with reference to the above embodiments, it will be understood by those skilled in the art that various modifications and changes can be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. will be able

Claims (20)

In a method of operating a terminal in a communication system,
Receiving a message including configuration information for channel measurement from the base station;
receiving a first reference signal from the base station based on the configuration information included in the message;
determining a resource region to be used for transmission of a second reference signal based on a measurement result of the first reference signal; and
The method of operating a terminal comprising the step of transmitting information indicating the size of the resource region to the base station. The method according to claim 1,
The step of determining the resource area comprises:
performing a measurement operation on the first reference signal in a first sub-measurement region among the entire measurement region; and
and determining the first sub-measurement region as the resource region when the measurement result of the first reference signal exceeds a first threshold. The method according to claim 1,
The step of determining the resource area comprises:
performing a measurement operation on the first reference signal in a first sub-measurement region among the entire measurement region;
When the measurement result of the first reference signal is less than or equal to a first threshold,
performing a measurement operation on the first reference signal in a second sub measurement area larger than the first sub measurement area among the entire measurement area; and
and determining the second sub-measurement region as the resource region when the measurement result of the first reference signal in the second sub-measurement region exceeds the first threshold. The method according to claim 1,
The method of operation of the terminal,
receiving control information including scheduling information from the base station;
receiving data and the second reference signal from the base station based on the scheduling information;
updating the resource region based on a measurement result of the second reference signal; and
The method of operating a terminal further comprising transmitting information indicating the updated resource region to the base station. 5. The method according to claim 4,
Updating the resource area comprises:
performing a measurement operation on the second reference signal in a third sub-measurement region among the entire measurement region; and
When the measurement result of the second reference signal is greater than or equal to a second threshold and less than or equal to a third threshold, maintaining the third sub measurement region as the resource region;
The second threshold value is smaller than the third threshold value, the operating method of the terminal. 5. The method according to claim 4,
Updating the resource area comprises:
performing a measurement operation on the second reference signal in a third sub-measurement region among the entire measurement region;
When the measurement result of the second reference signal is less than the second threshold value or exceeds the third threshold value, the second reference is performed in a fourth sub measurement area having a size different from that of the third sub measurement area in the entire measurement area performing a measurement operation on the signal; and
When the measurement result of the second reference signal in the fourth sub-measurement region is equal to or greater than the second threshold and less than or equal to the third threshold, updating the fourth sub-measurement region to the resource region;
The second threshold value is smaller than the third threshold value, the operating method of the terminal. The method according to claim 1,
The message includes a threshold value, which is a reference for each measurement of the first reference signal and the second reference signal, and information indicating a measurement area in which each of the first reference signal and the second reference signal is measured, the terminal how it works. The method according to claim 1,
The message is mapped to a plurality of transmission regions in a domain including a first axis indicating the Doppler effect and a second axis indicating a propagation delay. 9. The method of claim 8,
A first transmission area among the plurality of transmission areas is arranged to be spaced apart from a second transmission area in a first axis of the domain. 9. The method of claim 8,
A first transmission area among the plurality of transmission areas is disposed to be spaced apart from a second transmission area on a second axis of the domain. A method of operating a base station in a communication system, the method comprising:
transmitting a message including configuration information for channel measurement to the terminal;
transmitting a first reference signal to the terminal based on the configuration information included in the message; and
Receiving information indicating a resource region determined based on the measurement result of the first reference signal from the terminal,
The resource region is used for transmission of a second reference signal, the operating method of the base station. 12. The method of claim 11,
The method of operation of the base station,
transmitting control information including scheduling information to the terminal;
transmitting data and the second reference signal to the terminal based on the scheduling information;
The method of operating a base station further comprising the step of receiving, from the terminal, information indicating an updated resource region based on the second reference signal. 13. The method of claim 12,
The message includes a threshold value, which is a reference for each measurement of the first reference signal and the second reference signal, and information indicating a measurement area in which each of the first reference signal and the second reference signal are measured, the base station how it works. 12. The method of claim 11,
and the message is mapped to a plurality of transmission transmission regions in a domain comprising a first axis indicating a Doppler effect and a second axis indicating a propagation delay. 15. The method of claim 14,
A method of operating a base station, wherein a first transmission area among the plurality of transmission areas is disposed to be spaced apart from a second transmission area in a first axis of the domain. 15. The method of claim 14,
A method of operating a base station, wherein a first transmission area among the plurality of transmission areas is disposed to be spaced apart from a second transmission area in a second axis of the domain. As a terminal in a communication system,
processor;
a memory in electronic communication with the processor; and
including instructions stored in the memory;
When the instructions are executed by the processor, the instructions cause the terminal to
receiving a message including configuration information for channel measurement from the base station;
receive a first reference signal from the base station based on the configuration information included in the message;
determining a resource region to be used for transmission of a second reference signal based on a measurement result of the first reference signal; and
Operating to cause transmission of information indicating the determined resource region to the base station, the terminal. 18. The method of claim 17,
When determining the resource region, the commands are the terminal,
performing a measurement operation on the first reference signal in a first sub measurement area among the entire measurement area; and
When the measurement result of the first reference signal exceeds a first threshold, the terminal operates to cause determination of the first sub measurement region as the resource region. 18. The method of claim 17,
When determining the resource region, the commands are the terminal,
performing a measurement operation on the first reference signal in a first sub measurement area among the entire measurement area;
performing a measurement operation on the first reference signal in a second sub measurement area larger than the first sub measurement area among the entire measurement area when the measurement result of the first reference signal is equal to or less than a first threshold; and
When the measurement result of the first reference signal in the second sub-measurement region exceeds the first threshold value, the terminal operates to cause determining the second sub-measurement region as the resource region. 18. The method of claim 17,
The commands are the terminal,
receive control information including scheduling information from the base station;
receive data from the base station based on the second reference signal and the scheduling information;
updating the resource region based on a measurement result of the second reference signal; and
The terminal operates to cause transmission of information indicating the updated resource region to the base station.

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