KR20210128917A - Radio communication method for time sensitive network, and apparatus therefor - Google Patents

Abstract

An operation method of a first terminal for a synchronized operation according to time-sensitive networking comprises the following steps of: receiving information on reference time from a base station; obtaining an offset of the first terminal with respect to the reference time or information capable of deriving the offset and deriving the offset from the information capable of deriving the offset; determining a time point at which uplink transmission is performed by reflecting the offset at the reference time; and performing the uplink transmission at the determined time point.

Description

A wireless communication method for a time-sensitive network and an apparatus therefor

The present invention relates to a wireless communication method and apparatus, and more particularly, to a wireless communication method and apparatus for performing time-sensitive networking.

In a time-sensitive network, several terminals may perform synchronized operations. For example, there may be a case where several robots perform motions in a series order or perform certain motions at the same time. Such an operation may be managed by the control unit of each robot (ie, the terminal), and it is preferable that the control units of the terminals share a common time.

Each terminal may have its own clock, but the clock of the terminal may not be accurate. In this case, an operation error may occur while terminals belonging to the same group that need to perform a synchronized operation operate according to different times. Accordingly, at least terminals belonging to the same group need to share time from a clock as a reference. The time may be received by the terminal in the form of a message. Since the shared time may cause an error as much as the path delay, it is preferable that the terminal can estimate the correct time by compensating for this.

An object of the present invention for solving the above problems is to provide a method of operating a terminal for a synchronized operation according to time-sensitive networking.

Another object of the present invention for solving the above problems is to provide a method of operating a base station for synchronized operation according to time-sensitive networking.

Another object of the present invention for solving the above problems is to provide a configuration of a terminal and a base station for synchronized operation according to time-sensitive networking.

An embodiment of the present invention for achieving the above object is an operating method of a first terminal for synchronized operation according to time-sensitive networking, the method comprising: receiving information about a reference time from a base station; obtaining an offset of the first terminal with respect to the reference time or information from which the offset can be derived, and deriving the offset from information from which the offset can be derived; determining a time point at which uplink transmission is performed by reflecting the offset in the reference time; and performing the uplink transmission at the determined time point.

The reference time is generated by a global reference clock of the base station and received from the base station, or is generated by a global reference clock of a second terminal other than the first terminal and transmits the base station from the second terminal. can be received through

The reference time may be commonly applied to a terminal group including the first terminal and the second terminal.

The offset is a method based on timing advance (TA), or a round-trip-time (RTT, round-trip time) or Rx-Tx time difference measured by the first terminal and Rx- It may be obtained in a manner based on a combination of Tx time differences.

The TA may be defined by a difference between a boundary of a downlink slot received by the first terminal and a boundary of an uplink slot transmitted by the first terminal having the same index as the downlink slot.

The RTT may be measured by the first terminal based on the downlink reference signal of the base station and the uplink reference signal of the first terminal, or may be measured by the base station and transmitted from the base station to the first terminal.

The downlink reference signal is at least one of a downlink positioning reference signal (PRS), a synchronization signal (SS)/physical broadcast cahnnel (PBCH) block, and a channel state information (CSI)-RS, and the uplink reference signal is It may be at least one of a link PRS and a sounding reference signal (SRS).

When the RTT is measured in the first terminal, the RTT measurement using the downlink reference signal is triggered by downlink control information (DCI), and the DCI is the downlink reference signal. Information indicating the resource may be additionally included.

When the DCI allocates a downlink transport block (TB), a link physical data channel (PDSCH, physical downlink shared channel) to resource elements (RE) to which the downlink reference signal is not mapped. Whether rate matching for mapping .

The offset of the first terminal or information capable of deriving the offset is DCI or terminal group-specific PDSCH included in a UE-specific downlink physical control channel (PDCCH). It may be received from the base station through an included MAC random access response (RAR) or MAC CE (control element), or may be measured by the first terminal and reported to the base station through a terminal-specific uplink channel.

When the offset is obtained in a manner based on timing advance (TA), the MAC RAR or the MAC CE includes a timing advance command (TAC) that is an initial value of TA or a value accumulated in a current TA can do.

The MAC RAR or the MAC CE may include information on a unit time applied to the TA and/or the TAC.

An embodiment of the present invention for achieving the above other object is an operating method of a base station for synchronized operation according to time-sensitive networking, based on a reference time generated by a global reference clock. providing information on the first terminal; obtaining an offset of the first terminal with respect to the reference time or information for deriving the offset and providing it to the first terminal; and performing uplink reception for the first terminal, wherein the first terminal may perform uplink transmission corresponding to the uplink reception at a time determined by reflecting the offset in the reference time. .

The reference time may be commonly applied to a terminal group including the first terminal and the second terminal.

The offset is a method based on timing advance (TA), or a round-trip-time (RTT, round-trip time) or Rx-Tx time difference measured by the first terminal and Rx- It may be obtained in a manner based on a combination of Tx time differences.

The RTT may be measured by the base station based on the downlink reference signal of the base station and the uplink reference signal of the first terminal and transmitted from the base station to the first terminal.

The downlink reference signal is at least one of a downlink positioning reference signal (PRS), a synchronization signal (SS)/physical broadcast cahnnel (PBCH) block, and a channel state information (CSI)-RS, and the uplink reference signal is It may be at least one of a link PRS and a sounding reference signal (SRS).

The offset of the first terminal or information capable of deriving the offset is DCI or terminal group-specific PDSCH included in a UE-specific downlink physical control channel (PDCCH). It may be provided to the first terminal through the included MAC random access response (RAR) or MAC CE (control element).

When the offset is obtained in a manner based on timing advance (TA), the MAC RAR or the MAC CE includes a timing advance command (TAC) that is an initial value of TA or a value accumulated in a current TA can do.

The MAC RAR or the MAC CE may include information on a unit time applied to the TA and/or the TAC.

By using the embodiments of the present invention, it is possible to obtain time synchronization necessary for several terminals to perform a synchronized operation in a time-sensitive network. Accordingly, the efficiency and reliability of the communication system based on the time-sensitive network may be improved.

1 is a conceptual diagram illustrating an example in which time-synchronized terminals perform synchronized operations in a time-sensitive network.
2 is a conceptual diagram for explaining another example in which time-synchronized terminals perform synchronized operations in a time-sensitive network.
3 and 4 are conceptual diagrams for explaining a method of measuring a bidirectional delay (RTD) using an RTT-based method.
5A and 5B are conceptual diagrams illustrating embodiments of a MAC RAR including a TAC.
6 and 7 are conceptual diagrams for explaining examples of MAC CEs including TAC.
8 and 9 are conceptual diagrams for explaining an example of MAC CEs including an offset.
10A, 10B, 11A, 11B, 12A, 12B, 13A, and 13B are conceptual diagrams illustrating the structures of a MAC CE including information indicating a unit applied to a TAC.
14A and 14B are conceptual diagrams illustrating structures of a MAC RAR including information indicating a unit applied to TAC.
15 is a conceptual diagram for explaining a case of indexing combinations of TAG ID and TAC units.
16A to 16D and 17A to 17D are conceptual diagrams for explaining the structures of a MAC CE including information for HARQ-ACK transmission.
18 is a conceptual diagram for explaining a difference between boundaries of downlink slots derived from reception times of a downlink reference signal.
19 is a block diagram illustrating the configuration of a communication node according to an embodiment of the present invention.

Since the present invention can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings and described in detail in the detailed description. 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. In describing each figure, like reference numerals have been used for like elements.

Terms such as first, second, A, and B 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. The term “and/or” includes a combination of a plurality of related listed items or any of a plurality of related listed items.

When a component is referred to as being “connected” or “connected” to another component, it is understood that the other component may be directly connected or connected to the other component, but other components 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 no other element is present 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 commonly used dictionaries 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.

In the following, a wireless communication network to which embodiments according to the present invention are applied will be described. A wireless 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 wireless communication networks.

Hereinafter, methods for providing information on propagation delay in order to improve synchronization performance in a time-sensitive network are described.

(1) How to create a time-sensitive networking group

Hereinafter, a case in which several terminals perform a synchronized operation in a time-sensitive network may be considered. For example, there may be a case where several robots perform motions in a series order or perform certain motions at the same time. Such an operation may be managed by the control unit of each robot (ie, the terminal), and it is preferable that the control units of the terminals share a common time.

1 is a conceptual diagram illustrating an example in which time-synchronized terminals perform synchronized operations in a time-sensitive network.

Referring to FIG. 1 , a base station gNB having a global reference clock and terminals UE1 to UE1 that operate in synchronization with the global reference clock using an offset with respect to the time of the global reference clock. UE5) is shown.

For example, some devices in a power grid control network may perform an operation based on wireless communication. In this case, the devices should be able to share a common time. The time synchronization that the control unit of the terminal or devices of the power control network should have should have an error of less than 1 us. The area in which such time synchronization can be maintained has variable restrictions depending on the terminal or power control network, and Table 1 summarizes these scenarios. Specifically, Table 1 summarizes synchronization performance conditions in a time-sensitive network stipulated in ^{3 rd generation partnership project (3GPP) TS22.104.}

scenario Number of devices belonging to group sharing time synchronization Maximum tolerance of time synchronization service area Communication between control units of industrial robots 300 or less within 1us Within 100m X 100m video streaming 10 or less within 10us within 2500m ² Communication between control units in the power control network 100 or less within 1us within 20 km ²

The terminals may form a group for synchronized operation. 1 illustrates a case in which terminals form two terminal groups. In order to form terminal groups, the base station may indicate the group identifier to each terminal supporting time-sensitive networking through higher layer signaling. The group identifier may be a radio network temporary identifier (RNTI).

Method 1-1: The base station may indicate the group identifier to the terminal through higher layer signaling.

Terminals belonging to the same group may share the same time with each other. To this end, the terminals may receive time-related information from the base station. For example, the base station may transmit a physical downlink shared channel (PDSCH) including coordinated universal time (UTC). Alternatively, the information may be included in system information and transmitted in a broadcast manner. Alternatively, the information may be transmitted to some terminals in a multicast method or a unicast method.

Each terminal may have its own clock, but the clock of the terminal may not be accurate. In this case, when terminals belonging to the same group that need to perform a synchronized operation operate according to different clocks, an operation error may occur. Therefore, at least the clocks of the terminals belonging to the same group are synchronized, or at least it is necessary to estimate the difference between the clocks of the terminals belonging to the same group.

2 is a conceptual diagram for explaining another example in which time-synchronized terminals perform synchronized operations in a time-sensitive network.

In the time sensitive network shown in Figure 1, only the base station (gNB) may have a global reference clock. On the other hand, referring to FIG. 2 , specific terminals (eg, UE1 and UE4) other than the base station may have reference clocks. The terminals may receive the reference clock time (ie, the reference time) through the base station. UE2 and UE3 may receive the time of the reference clock of UE1 through the base station gNB, and UE5 may receive the time of the reference clock of UE4 through the base station gNB.

Devices (or terminals) belonging to a service area must maintain time synchronization within a predetermined error. When the size of the service area increases, the delay time (ie, propagation delay) in the radio section must be considered. That is, even if the time of the reference clock is shared wirelessly, each of the devices (or terminals) receiving it must correct the shared time with its own delay time.

은 옵셋(

)을 가지고 있는 것으로 표현될 수 있다. 따라서, 그룹 1 및 그룹 2에 속한 단말들 각각은 자신에게 적용될 옵셋을 이용하여 기준 클록을 보상하여야, 자신의 그룹에 속한 다른 단말들과 동기화된 동작을 수행할 수 있다. 따라서, 단말이

의 값을 알 수 있도록 하는 방법이 필요하다.For example, each terminal for shared time

Silver offset (

) can be expressed as having Therefore, each of the terminals belonging to the group 1 and the group 2 must compensate the reference clock by using the offset applied to the terminal to perform synchronized operations with the other terminals belonging to the group. Therefore, the terminal

We need a way to know the value of .

은 기지국과 단말

가 공유하는 타이밍 어드밴스(timing advance, TA) 또는 라운드-트립 타임(round trip time, RTT)로부터 얻어질 수 있다. 단말

가

에 기반한 보상을 수행할 수 있도록, 기지국은

의 값 또는

를 도출할 수 있는 정보를 단말

에게 전송할 수 있다. 기지국은 상기 정보를 유니캐스트 방식 또는 멀티캐스트 방식으로 단말

에게 전송할 수 있다.For example,

is the base station and the terminal

It can be obtained from timing advance (TA) or round trip time (RTT) shared by . terminal

go

In order to be able to perform compensation based on

the value of or

information that can be derived from the terminal

can be sent to The base station transmits the information to the terminal in a unicast method or a multicast method

can be sent to

The UE may estimate the propagation delay in a TA-based method or an RTT-based method, but the accuracy and protocol/signaling burdens of these methods are different from each other. Specifically, the TA-based scheme has relatively low accuracy, but does not require or minimizes separate signaling. On the other hand, the RTT-based scheme has relatively high accuracy but requires separate signaling.

가 산업용 로봇의 제어부에 해당한다면, 높은 정확도가 요구되기 때문에 RTT에 기반한 방식을 적용하는 것이 바람직하다. 반면, 단말

가 전력 제어망의 제어부에 해당한다면, 다소 낮은 정확도가 요구되므로, TA에 기반한 방식을 적용하는 것도 가능하다. 이러한 경우, 단말

및/또는 단말 그룹이 속한 시나리오에 따라서 TA에 기반한 방식 또는 RTT에 기반한 방식이 적용되도록 기지국이 상위계층 시그널링으로 지시(또는 설정)하는 것이 바람직하다.For example, in the scenario of Table 1, the terminal

If is a control unit of an industrial robot, it is desirable to apply an RTT-based method because high accuracy is required. On the other hand, the terminal

If is a control unit of the power control network, a somewhat low accuracy is required, so it is also possible to apply a TA-based method. In this case, the terminal

And/or it is preferable that the base station instruct (or configure) with higher layer signaling so that the TA-based method or the RTT-based method is applied according to a scenario to which the terminal group belongs.

Method 1-2: The terminal may be instructed (or configured) through RRC signaling to apply the TA-based method or the RTT-based method from the base station to estimate the propagation delay.

(i) method based on TA

)에게 TA를 전달하여 단말이 전파 지연(또는

)을 추정하도록 할 수 있다. TA는 하향링크 수신 타이밍과 상향링크 전송 타이밍의 차이로 정의된다. 보다 구체적으로는, 단말이 수신한 하향링크 슬롯의 경계(boundary)와 단말이 전송하는 상기 하향링크 슬롯과 동일한 슬롯 인덱스를 가진 상향링크 슬롯의 경계가 가지는 차이에 기반하여 TA가 도출될 수 있다. TA는 하향링크 전파 지연과 상향링크 전파 지연의 합일 수 있다. 일반적으로 하향링크 전파 지연과 상향링크 전파 지연은 작은 차이를 가진다고 간주될 수 있으므로, 하향링크 전파 지연과 상향링크 전파 지연은 서로 같은 값으로 해석될 수 있다. 즉, 전파 지연은 TA의 추정치의 절반으로 계산될 수 있다.The base station is the terminal (that is, the terminal

) by sending the TA to the terminal to delay the propagation (or

) can be estimated. TA is defined as a difference between downlink reception timing and uplink transmission timing. More specifically, the TA may be derived based on a difference between a boundary of a downlink slot received by the terminal and a boundary of an uplink slot having the same slot index as the downlink slot transmitted by the terminal. The TA may be the sum of the downlink propagation delay and the uplink propagation delay. In general, since the downlink propagation delay and the uplink propagation delay may be regarded as having a small difference, the downlink propagation delay and the uplink propagation delay may be interpreted as the same value. That is, the propagation delay can be calculated as half the estimate of the TA.

(ii) RTT-based scheme

또는

를 도출할 수 있는 정보)이 추정될 수 있다. 기지국으로부터 수신되는 하향링크 참조신호(예컨대, CSI-RS(channel state information-reference signal), SS(synchronization signal)/PBCH(physical broadcast channel) 블록, 또는 하향링크 PRS(positioning reference signal))와 단말

가 전송하는 상향링크 참조신호를 이용하여 송신 시점과 수신 시점 간의 차이를 측정하는 방식이 적용될 수 있다. 즉, 이는 라운드-트립 지연(round trip delay, RTD)를 추정하는 방법으로 해석될 수 있다.On the other hand, propagation delay (or propagation delay using information other than TA)

or

information that can be derived) can be estimated. A downlink reference signal (eg, a channel state information-reference signal (CSI-RS), a synchronization signal (SS)/physical broadcast channel (PBCH) block, or a downlink positioning reference signal (PRS)) received from the base station and the terminal

A method of measuring a difference between a transmission time and a reception time by using an uplink reference signal transmitted by . That is, this may be interpreted as a method of estimating a round trip delay (RTD).

For example, the terminal may receive a downlink reference signal from the base station and may also transmit an uplink reference signal, and the base station may receive it. Using the time difference between the transmission time and the reception time, the bidirectional delay (RTD) of the link between the base station and the terminal can be confirmed.

3 and 4 are conceptual diagrams for explaining a method of measuring a bidirectional delay (RTD) using an RTT-based method.

Specifically, FIG. 3 illustrates an embodiment in which RTT is measured in a base station, and FIG. 4 illustrates an embodiment in which RTT is measured in a terminal.

Although it has been described in FIGS. 3 and 4 that the transmission of the uplink signal or channel and the reception of the downlink signal or channel have a predetermined time interval, the present invention is not limited thereto. In general, since transmission of an uplink signal or channel and reception of a downlink signal or channel are performed independently, T ₁ and T ₂ and T ₃ and T ₄ are used to derive a downlink delay time and an uplink delay time. This is only an obtained time point, and may not mean a precedence or causal relationship between reception of a downlink signal and channel and transmission of an uplink signal and channel.

는 상향링크 슬롯이 시작하는 시간을 T₃로 간주할 수 있고, 기지국은 상향링크 슬롯이 시작하는 시간을 T₄로 간주할 수 있다.또는, 기지국은 하향링크 참조신호를 T₁에서 전송한다(또는, 하향링크 참조신호의 첫 심볼의 첫 경로(path)가 T₁에서 전송된다). 단말

는 이를 T₂에서 수신할 수 있다. 소정의 시간이 흐른 이후에, 단말은 T₃에서 상향링크 참조신호를 전송할 수 있다. 기지국은 T₄에서 상향링크 참조신호를 수신할 수 있다. 예를 들어, 단말이 하향링크 참조신호를 수신하고 상향링크 참조신호를 전송할 수 있는 최초의 시간 자원을 도출했을 때, 해당 시간 자원이 T₃로 주어질 수 있다. T₃와 T₂의 차이는 기지국으로부터 상위계층 시그널링으로 단말에게 지시되어, 기지국은 T₄에서 UL RS를 수신할 수 있다3 and 4, a downlink signal or channel (eg, DL PRS) is transmitted in a downlink slot, and an uplink signal or channel (eg, UL PRS, SRS, or PRACH) is transmitted in an uplink slot. can be After a predetermined time elapses, the base station starts a downlink slot in _{T 1 .} The terminal may be operating based on a time different from that of the base station, and it is regarded as starting a downlink slot at _{T 2 .} terminal

may consider the time at which the uplink slot starts as T ₃ , and the base station may consider _{the time at which the uplink slot starts as T 4} . Alternatively, the base station transmits a _{downlink reference signal at T 1 (} Alternatively, the first path of the first symbol of the downlink reference signal is transmitted in _{T 1 ).} terminal

may receive it at T _{2 .} After a predetermined time elapses, the terminal may transmit an uplink reference signal at _{T 3 .} The base station may receive an uplink reference signal at _{T 4 .} For example, when the terminal derives the first time resource for receiving the downlink reference signal and transmitting the uplink reference signal, the corresponding time resource may be given as _{T 3 .} The difference between T ₃ and T ₂ is indicated to the UE by higher layer signaling from the base station, so that the base station can receive the UL RS at _{T 4 .}

As illustrated in FIG. 3 , the downlink propagation delay _{may be calculated as T 2} -T ₁ , and the uplink propagation delay may be calculated as _{T 4} -T _{3 .} RTD is given as their sum, and can be expressed as _{RTD = (T 2} -T ₁ )+(T ₄ -T ₃ ) = (T ₄ -T ₁ )-(T ₃ -T _{2 ). That is, the RTD is given by the difference between the amount (T 4} -T ₁ ) indicating the difference between the reception time and the transmission time in the base station and the _{amount (T 3} -T ₂ ) indicating the difference between the transmission time and the reception time in the terminal.

가 기지국으로 상향링크 참조신호를 전송하는 것에서부터 RTT가 측정될 수 있다. 두가지 경우들의 차이는, RTT를 측정한 이후 전파 지연을 보상하는 방식에서 나타날 수 있다. 즉, 도 4의 경우에서는, 상향링크 전파 지연이 T₄-T₃으로 계산될 수 있고, 하향링크 전파 지연이 T₂-T₁으로 계산될 수 있다. RTD는 이들의 합으로 주어진다. RTD = (T₄-T₃) + (T₂-T₁) = (T₂-T₃)-(T₁-T₄) 이기 때문에, RTD는 단말에서의 수신 시점과 전송 시점 간의 차이를 나타내는 양(T₂-T₃)과 기지국에서의 전송 시점과 수신 시점 간의 차이를 나타내는 양(T₁-T₄)의 차이로 주어진다.Meanwhile, in the case of FIG. 3, the RTT is measured from when the base station transmits the downlink reference signal to the terminal, but in the case of FIG. 4, the terminal

RTT may be measured from transmitting an uplink reference signal to the base station. The difference between the two cases may appear in the way of compensating for the propagation delay after measuring the RTT. That is, in the case of FIG. 4 , the uplink propagation delay _{may be calculated as T 4} -T ₃ , and the downlink propagation delay may be calculated as _{T 2} -T _{1 .} The RTD is given as their sum. Since RTD = (T ₄ -T ₃ ) + (T ₂ -T ₁ ) = (T ₂ -T ₃ )-(T ₁ -T ₄ ), the RTD represents the difference between the reception time and the transmission time in the terminal. It is given as the difference between the quantity (T ₂ -T _{3 ) and the quantity (T 1} -T ₄ ) representing the difference between the transmission time and the reception time in the base station.

Transmission/reception time difference (Rx-Tx time difference) (the difference between the reception (transmission) time and the transmission (reception) time at the terminal or the difference between the transmission (reception) time and the reception (transmission) time at the base station) is estimated at the base station or the terminal may be, and their values may be defined differently. When the time of the uplink slot received from the terminal is expressed as TRX and the time of the downlink slot closest to the corresponding uplink slot among the downlink slots transmitted to the terminal is expressed as TTX, the gNB Rx-Tx time difference is (TRX - TTX ) can be defined as When the time of the downlink slot received from the base station is TRX and the time of the uplink slot closest to the corresponding downlink slot among uplink slots transmitted to the base station is expressed as TTX, the UE Rx-Tx time difference is (TRX - TTX ) can be defined as

A device for measuring RTT and a device for compensating for propagation delay may be the same or different. Four combinations of a device for measuring RTT and a device for compensating for propagation delay can be given.

The first combination is when the base station measures the RTT and compensates for propagation delay. In this case, the terminal may perform an operation of receiving the downlink reference signal and transmitting the uplink reference signal. The Rx-Tx time difference measured by the UE may be reported to the base station. Since the base station implements in advance compensation for the propagation delay, the terminal does not need to separately calibrate the clock.

The second combination is when the base station measures RTT and the terminal compensates for propagation delay. In this case, the terminal may receive the downlink reference signal and transmit the uplink reference signal, and receive the RTT or Rx-Tx time difference measured by the base station from the base station to correct the clock of the terminal. If the Rx-Tx time difference is received from the base station, the UE may estimate the RTT by combining the received Rx-Tx time difference and the Rx-Tx time difference of the UE.

The third combination is a case in which the UE measures RTT and compensates for propagation delay. In this case, the terminal may perform an operation of transmitting an uplink reference signal and receiving a downlink reference signal. The base station may indicate to the terminal the measured RTT or Rx-Tx time difference. If the Rx-Tx time difference is received from the base station, the terminal may estimate the RTT in combination with the Rx-Tx time difference of the terminal.

The fourth combination is when the UE measures the RTT and the base station compensates for the propagation delay. In this case, the terminal may perform transmission of an uplink reference signal and reception of a downlink reference signal. The UE may report the RTT or Rx-Tx time difference to the base station. Since the base station implements in advance compensation for the propagation delay, the terminal does not need to separately calibrate the clock.

에서 전파 지연을 보상하기 위해서는, 송수신 시차(Rx-Tx timing difference 또는 Tx-Rx timing difference)가 기지국으로부터 단말에게 전달되어야 한다. 즉, 단말

가 기지국에서 추정한 값(T₄-T₁, T₁, 또는 T₄)을 알고 있어야 한다. 기지국은 단말

에게 해당 값 자체 또는 해당 값을 지시하는 인덱스를 전달할 수 있다. 이는

를 도출할 수 있는 정보로 활용될 수 있다.terminal

In order to compensate for the propagation delay in , a transmission/reception time difference (Rx-Tx timing difference or Tx-Rx timing difference) should be transmitted from the base station to the terminal. That is, the terminal

_{The value (T 4} -T ₁ , T ₁ , or T ₄ ) estimated by the base station should be known. base station is the terminal

You can pass the value itself or an index pointing to the value. this is

can be used as information from which to derive

에서 추정한 값(T₃-T₂, T₂, 또는 T₃)을 알고 있어야 한다. 단말

는 기지국에게 해당 값 자체 또는 해당 값을 지시하는 인덱스(또는 옵셋)를 보고할 수 있어야 한다.Conversely, in order to compensate for propagation delay in the base station, the base station

The estimated value (T ₃ -T ₂ , T ₂ , or T ₃ ) must be known. terminal

should be able to report the corresponding value itself or the index (or offset) indicating the corresponding value to the base station.

에게 하향링크 참조신호(또는 하향링크 PRS, SS/PBCH 블록, 또는 CSI-RS)를 수신하도록 지시할 수 있으며, 또한 상향링크 참조신호(또는, 상향링크 PRS 또는 SRS(sounding reference signal))를 전송하도록 지시할 수 있다. 이하에서는, 하향링크 PRS가 RTT 측정을 위해 사용되는 경우가 설명된다. 그러나, 하향링크 PRS 이외에 다양한 하향링크 참조신호들이 이용될 수 있다.In order to measure the RTT, the base station is

to receive a downlink reference signal (or downlink PRS, SS/PBCH block, or CSI-RS), and also transmits an uplink reference signal (or uplink PRS or SRS (sounding reference signal)) can be instructed to do so. Hereinafter, a case in which downlink PRS is used for RTT measurement will be described. However, in addition to the downlink PRS, various downlink reference signals may be used.

Method 1-3: The base station may configure the downlink PRS for each bandwidth part (BWP) of the terminal.

According to the conventional method, the downlink PRS may be transmitted from one or more base stations to the terminal for the purpose of measuring the location of the terminal. Accordingly, the downlink PRS may be configured irrespective of the BWP configured in the terminal. The UE may switch the downlink BWP to receive the downlink PRS. This can cause latency. Therefore, when the downlink PRS is used for the purpose of estimating the RTT or Rx-Tx time difference, the downlink PRS is set in the downlink BWP configured for the terminal, so that the terminal does not consume a separate time for BWP switching. It is desirable to be able to receive the downlink PRS.

Method 1-4: The base station may receive a downlink PRS and/or a downlink reference signal and instruct the terminal to measure the Rx-Tx time difference or RTT, and triggering may be performed using at least scheduling DCI. can

According to the conventional method, since the downlink PRS is received periodically, the UE can receive the downlink PRS only in a predetermined slot and measure the RTT. However, in order to measure the RTT or Rx-Tx time difference, the downlink PRS and the uplink reference signal may be considered simultaneously, and the measurement of RTT using the downlink PRS and the uplink reference signal should be triggered by DCI. .

When the measurement of RTT is indicated by the scheduling DCI, if the scheduling DCI is a DCI for scheduling downlink transmission (ie, DL-DCI), the PDSCH is only provided to resource elements (REs) to which the downlink PRS is not mapped. can be mapped. In this case, the UE may map the PDSCH through rate matching or puncturing. This is embodied in Methods 1-5, which will be described later.

The field of the scheduling DCI may represent a downlink RS resource index (eg, a downlink PRS resource index (resource index or CSI-RS resource index). The UE is indicated by RRC signaling for several downlink RS resources, Among them, it may be assumed that one or more DL RS resource(s) are triggered to measure RTT or Rx-Tx time difference by a field of DL-DCI.

On the other hand, when the SS / PBCH block is used for RTT measurement instead of the downlink RS, triggering of the RTT measurement (or Rx-Tx time difference measurement) using the above-described downlink RS may not be considered.

Method 1-5: In method 1-4, a separate field is introduced in DL-DCI to indicate whether RTT measurement using downlink RS or triggering of Rx-Tx time difference and/or rate matching for PDSCH is applied can be

는 기지국에게 송수신 시차 값을 보고해야 할 수 있다. 이러한 경우, 기지국은 상향링크 전송을 스케쥴링하는 DCI(즉, UL-DCI)를 이용해서 단말에게 송수신 시차(즉,

를 도출할 수 있는 정보)를 측정하고 PUSCH를 통해 보고하도록 지시할 수 있다. 송수신 시차 값은 단말

에 의해 주기적으로 전송되기 보다는 기지국의 동적인 할당에 의해서 보고될 수 있어야 한다. 송수신 시차의 측정값이 상위계층 메시지에 포함되어 전송되는 경우, 기지국은 단말

에게 UL-DCI를 이용해서 상위계층 메시지가 전송될 PUSCH의 자원을 할당해야 한다.terminal

may have to report the transmission/reception time difference value to the base station. In this case, the base station uses DCI (ie, UL-DCI) for scheduling uplink transmission to provide the terminal with a transmission/reception time difference (ie, UL-DCI).

information that can be derived) may be measured and reported through PUSCH. The transmission/reception time difference value is the terminal

It should be able to be reported by the dynamic allocation of the base station rather than being transmitted periodically by the BS. When the measurement value of the transmission/reception time difference is included in the upper layer message and transmitted, the base station is the terminal

PUSCH resource to which the upper layer message will be transmitted must be allocated using UL-DCI.

를 도출할 수 있는 정보를 보고할지 여부를 지시하기 위해서, UL-DCI에 별도의 필드가 도입될 수 있다.Method 1-6: In method 1-4, it indicates to use the downlink RS for RTT measurement or Rx-Tx time difference measurement, or

In order to indicate whether to report information that can derive

를 도출할 수 있는 정보를 보고할지 여부를 지시하는 것이 바람직하다. 단말

가 수신한 UL-DCI의 특정한 필드가 이용될 경우, UL-DCI를 수신한 슬롯을 기준으로 하향링크 RS의 시간 자원이 기술 규격에 의해서 주어지고,

를 도출할 수 있는 정보를 상위계층 메시지에 포함하는 PUSCH에 대한 자원이 지시될 수 있다.In general, the transmission of the PUSCH including the higher layer message is preferably indicated by the higher layer message. However, in the case of transmission/reception time difference, since the downlink RS is involved in the physical layer, UL-DCI indicates to use the downlink RS for RTT measurement or Rx-Tx time difference measurement or

It is desirable to indicate whether to report information that can derive terminal

When a specific field of the UL-DCI received by is used, the time resource of the downlink RS is given by the technical standard based on the slot in which the UL-DCI is received,

A resource for the PUSCH including information for deriving , in a higher layer message may be indicated.

가 여러 개의 하향링크 RS 자원들을 RRC 시그널링으로 설정받은 경우, UL-DCI의 필드는 하나 또는 그 이상의 하향링크 RS 자원(들)을 지시하는 인덱스가 포함하고, 단말은 이를 바탕으로 하향링크 RS를 수신할 수 있다.Also, the terminal

When a plurality of downlink RS resources are set by RRC signaling, the UL-DCI field includes an index indicating one or more downlink RS resource(s), and the terminal receives the downlink RS based on this. can do.

는 UL-DCI의 특정한 필드로부터, 단말이 하향링크 RS를 수신하고

를 도출할 수 있는 정보를 보고해야 하는 것을 알 수 있다. 단말

는 UL-DCI가 수신된 슬롯(또는 기술 규격에서 정한 슬롯 옵셋이 적용된 슬롯)에서 DL RS를 수신할 것으로 기대하며, UL-DCI에서 지시하는 자원에서 PUSCH를 전송할 수 있다.

를 도출할 수 있는 정보는 PUSCH에서 포함되어 기지국으로 보고될 수 있다.For example, the terminal

From a specific field of UL-DCI, the UE receives the downlink RS and

It can be seen that information that can be derived should be reported. terminal

expects to receive the DL RS in the slot in which the UL-DCI is received (or the slot to which the slot offset determined in the technical standard is applied), and may transmit the PUSCH in the resource indicated by the UL-DCI.

Information capable of deriving ? may be included in the PUSCH and reported to the base station.

를 도출할 수 있는 정보의 보고는 주기적으로 수행될 수 있다. 이를 위해서, 기지국은 보고를 위한 주기 및 슬롯 옵셋을 단말

에게 RRC 시그널링으로 지시할 수 있다. 단말

는 주기적인 보고만을 수행할 수 있다. 또는, 단말

는 주기적인 보고와 트리거된 보고를 모두 수행할 수 있다.According to another method,

Reporting of information that can be derived can be performed periodically. To this end, the base station determines the period and slot offset for reporting to the terminal.

can be instructed by RRC signaling. terminal

can only perform periodic reporting. or, the terminal

can perform both periodic and triggered reporting.

(2) A method of using a UE-specific downlink channel

에게

의 값 또는

를 도출할 수 있는 정보를 전송하기 위해 단말

에 대한 하향링크 채널과는 다른 하향링크 채널을 이용할 수 있다. 기지국은 각각의 단말이 가지는 라디오 식별자를 이용할 수 있다. 이러한 라디오 식별자는 C(cell)-RNTI, MCS(modulation and coding scheme)-C-RNTI, 또는 CS(configured scheduling)-RNTI일 수 있다.In the case of unicast, the base station is

to

the value of or

In order to transmit information that can derive

It is possible to use a downlink channel different from the downlink channel for . The base station may use a radio identifier of each terminal. Such a radio identifier may be a C (cell)-RNTI, a modulation and coding scheme (MCS)-C-RNTI, or a configured scheduling (CS)-RNTI.

에게 전송될 DCI를 스크램블링할 때 단말

의 라디오 식별자를 적용할 수 있다.

의 값 또는

를 도출할 수 있는 정보는 DCI 또는 PDSCH에 포함될 수 있다.base station is the terminal

When scrambling DCI to be transmitted to the terminal

A radio identifier of can be applied.

the value of or

Information from which to derive may be included in DCI or PDSCH.

(i) Method of using UE-specific PDCCH

에게 전송되는 정보(즉,

의 값 또는

를 도출할 수 있는 정보)를 포함할 수 있다.Method 2-1: The specific field of DCI is the terminal

information transmitted to (i.e.,

the value of or

information that can be derived).

은 DCI의 스크램블링에 기초하여 해당 DCI가 단말

에게 전송되는 것을 확인할 수 있다. DCI의 특정 필드는

의 값 또는

를 도출할 수 있는 정보를 포함할 수 있다. 기지국은 해당 필드의 길이 및 DCI에서 해당 필드의 위치를 상위계층 시그널링으로 단말에게 지시할 수 있다. 단말은 해당 필드로부터

의 값 또는

를 도출할 수 있는 정보를 확인할 수 있다. 따라서, 단말은 기지국으로부터 수신한 기준 시간을 보정할 수 있다. 한편, 해당 DCI는 단말

에게 전송 블록(TB, transport block)을 할당할 수도 있지만, 단말

에게 TB를 할당하지 않을 수도 있다.terminal

Based on the scrambling of DCI, the DCI is the terminal

It can be checked that it is being sent to Certain fields in DCI are

the value of or

It may contain information that can be derived. The base station may indicate to the terminal the length of the corresponding field and the position of the corresponding field in DCI through higher layer signaling. the terminal from the field

the value of or

information that can be derived can be found. Accordingly, the terminal can correct the reference time received from the base station. On the other hand, the DCI is the terminal

It is also possible to allocate a transport block (TB) to the terminal, but

may not allocate TB to .

의 값 또는

를 도출할 수 있는 정보)를 포함하는 경우, 단말은 기지국에게 해당 정보에 대한 HARQ(hybrid automatic repeat request)-ACK(acknowledgement)을 전송할 수 있다.Method 2-2: DCI

the value of or

), the terminal may transmit a hybrid automatic repeat request (HARQ)-acknowledgement (ACK) for the corresponding information to the base station.

의 값 또는

를 도출할 수 있는 정보)를 성공적으로 복호한 것으로 간주할 수 있다.When DCI does not allocate a TB, the UE may transmit HARQ-ACK using the resource of PUCCH indicated by DCI. Therefore, according to Method 2-2, the UE may transmit the HARQ-ACK according to the DCI decoding result through the PUCCH (or PUSCH). Since blind decoding is performed to decode the DCI, the terminal may not decode the corresponding DCI any more when a NACK is derived in the process of descrambling the DCI. When the ACK is derived in the process of descrambling the DCI, the UE can know that the decoding of the DCI has been successful. Accordingly, the UE may derive the ACK and transmit the ACK through the PUCCH (or PUSCH). When the base station receives an ACK from the terminal, the terminal receives the corresponding information from DCI (that is,

the value of or

information that can be derived) can be considered to have been successfully decoded.

의 값 또는

를 도출할 수 있는 정보)를 성공적으로 복호한 것으로 간주할 수 있다.When DCI allocates a TB, the UE may transmit HARQ-ACK using the resource of PUCCH indicated by DCI. Therefore, according to Method 2-2, the UE may receive the PDSCH in the resource indicated by the DCI, and transmit the HARQ-ACK according to the result of decoding the TB through the PUCCH (or PUSCH). The UE may derive ACK or NACK according to the result of decoding the TB. Since the base station can interpret that the terminal has successfully received DCI when ACK or NACK is received from the terminal, the terminal receives the corresponding information included in the DCI (that is,

the value of or

information that can be derived) can be considered to have been successfully decoded.

(ii) Method of using UE-specific PDSCH

에게 전송되는 정보(즉,

의 값 또는

를 도출할 수 있는 정보)를 포함할 수 있다.Method 2-3: PDSCH is UE

information transmitted to (i.e.,

the value of or

information that can be derived).

는 DCI의 스크램블링에 기초하여 해당 DCI가 단말

에게 전송되는 것으로 가정할 수 있다. DCI에 의해 단말

를 위한 PDSCH가 할당될 수 있다. PDSCH는

의 값 또는

를 도출할 수 있는 정보를 포함할 수 있다. 일 예로,

를 도출할 수 있는 정보는 TA일 수 있다. 이 경우, MAC 계층에서 생성되는 MAC (sub)PDU에 TA가 포함될 수 있다.terminal

Based on scrambling of DCI, the DCI is the terminal

It can be assumed that it is transmitted to Terminal by DCI

A PDSCH for may be allocated. PDSCH is

the value of or

It may contain information that can be derived. For example,

The information that can be derived may be a TA. In this case, the TA may be included in the MAC (sub)PDU generated by the MAC layer.

The base station may receive PUSCH/PUCCH/SRS/PRACHs from several terminals. Accordingly, in order to maintain orthogonality therebetween, the base station may instruct each terminal to receive a TA so that PUSCH/PUCCH/SRS/PRACH of each terminal can be received within a predetermined time. The terminal can know the TA in the initial access phase with the base station, and thereafter, by receiving a TA command (TAC, TA command) through higher layer signaling, the TA can be increased, maintained, or decreased. As an example of higher layer signaling, a MAC layer message (eg, a MAC random access response (RAR) or a MAC control element (CE)) may be used.

The positions of bits and the order of bits constituting the MAC RAR or MAC CE described below are examples, and they may have a predetermined different order.

5A and 5B are conceptual diagrams illustrating embodiments of a MAC RAR including a TAC.

Figure 5a shows the structure of a fallback (fallback) RAR message, Figure 5b shows the structure of a success (success) RAR message. The base station may estimate the TA of the corresponding terminal using a physical random access channel (PRACH) preamble or SRS received from the terminal. The MAC RAR message received from the base station in the initial access phase includes the TAC. The MAC RAR message also includes an RNTI (ie, TC-RNTI) to be used by the UE to transmit message 3 (M3) PUSCH. The UE may decode the PDSCH to which the MAC RAR is mapped by using the RA-RNTI. Taking the case of the MAC RAR message of FIG. 5A as an example, when the UE transmits the M3 PUSCH based on the MAC RAR, the UE may use the TAC included in Octet 1 and Octet 2, and transmit the M3 PUSCH Uplink grants for this purpose may be derived from Octet 2, Octet 3, Octet 4, and Octet 5. Here, the bit marked with 'R' of Octet 1 is a reserved bit and may not be used for MAC RAR. On the other hand, after the initial connection is completed and the RRC connection is established, the base station may instruct the terminal to TAC by using the MAC CE.

6 and 7 are conceptual diagrams for explaining examples of MAC CEs including TAC.

Referring to FIG. 6 , according to the technical standard, information on TAC in a MAC (sub)PDU may be expressed by one byte. TAC is represented by 6 bits. A timing advance group (TAG) ID indicates identification information of a TAG to which the TAC is applied. When carrier aggregation is configured for the terminal, the base station may configure a TAG to which one or more serving cells belong to the terminal. Since the same TA may be applied to serving cells belonging to the TAG, the TAC may be indicated to the TAG.

Referring to FIG. 7 , MAC CE in which information on TAC is expressed by two bytes may be used. In this case, since the TAC is expressed by 12 bits, the TA may be expressed in the same range as in the MAC RAR message. Here, 'R' means a reserved bit and may not be used for a separate purpose.

Meanwhile, the TAC fields included in the MAC RAR message of FIGS. 5A and 5B and the MAC CE of FIGS. 6 and 7 may be interpreted differently for each UE. The value indicated by the MAC RAR message of FIGS. 5A and 5B and the TAC field of the MAC CE of FIG. 7 may be an initial TA value. Accordingly, the UE may not accumulate the value of the TAC field included in the MAC RAR message of FIGS. 5A and 5B and the MAC CE of FIG. 7 in the current TA of the UE. Instead, the UE may consider the value of the received TAC field as a new TA. Meanwhile, the value (ie, offset) of the TAC field included in the MAC CE of FIG. 6 may be accumulated in the TA of the UE. For convenience of description, regardless of whether the value of the TAC field is used as a new TA or a value accumulated in the TA, the value included in the TAC field of the MAC CE or MAC RAR is collectively referred to as the TAC.

단위로 주어지며,

로 정의된다. 단말이 상향링크 전송을 시작하는 시점은 하향링크 슬롯의 시작 시점에 TA를 적용한 시간만큼 앞서 있다. TDD(time division duplex)로 동작하는 경우, 수신 및 전송 스위칭(switching)을 위해서 기술규격에서 정하는 TA 옵셋(offset)(

)이 추가적으로 고려된다. TDD 모드에서는, TA와 TA 옵셋을 합친 값이

단위로 주어진다. 즉,

가 정의된다.TA is indicated to the terminal as a natural number, and the terminal can convert it by the method defined in the technical standard. For example, according to the technical specification (3GPP TS38 series), TA is

given in units,

is defined as The time at which the UE starts uplink transmission is ahead by the time at which the TA is applied to the start time of the downlink slot. When operating in TDD (time division duplex), TA offset (offset) (

) is additionally considered. In TDD mode, the sum of TA and TA offset is

given in units in other words,

is defined

가 발생한다. 30 kHz의 부반송파 간격을 가지는 BWP에서, 하나의 심볼은 약 37us의 길이를 가지므로, 이는 심볼 길이의 약 36%에 해당한다. 반면, FR1에서 동작하는 FDD 시스템에서 LTE와 공존하는 경우에는,

가 발생한다. 30 kHz의 부반송파 간격을 가지는 BWP에서, 하나의 심볼은 약 35.7us의 길이를 가지므로, 이는 심볼 길이의 약 57%에 해당한다.In the case of not coexisting with LTE in an FDD system operating in FR1 (frequency range 1),

occurs In the BWP having a subcarrier spacing of 30 kHz, one symbol has a length of about 37 us, which corresponds to about 36% of the symbol length. On the other hand, in the case of coexistence with LTE in an FDD system operating in FR1,

occurs In the BWP having a subcarrier spacing of 30 kHz, one symbol has a length of about 35.7 us, which corresponds to about 57% of the symbol length.

가 발생한다. 60 kHz의 부반송파 간격을 가지는 BWP에서, 하나의 심볼은 약 17.9us의 길이를 가지므로, 이는 심볼 길이의 약 125.3%에 해당한다.In addition, in a system operating in FR2 (frequency range 2),

occurs In the BWP having a subcarrier spacing of 60 kHz, one symbol has a length of about 17.9 us, which corresponds to about 125.3% of the symbol length.

의 시간이 필요하므로, 약

의 간격(interval)이 필요하다.In order for the terminal to change transmission and reception in half-duplex communication,

time is required, so about

interval is required.

로 주어진다. 30 kHz의 부반송파 간격을 가지는 BWP에서는

을 단위로 가지며, 60 kHz의 부반송파의 간격을 가지는 BWP에서는

을 단위로 가질 수 있다.The unit of TAC may have a value determined by the technical standard. For example, the unit of TAC is

is given as In BWP with subcarrier spacing of 30 kHz,

In the BWP having a unit of , and subcarrier spacing of 60 kHz,

can have as a unit.

(3) A method of using a UE group-specific downlink channel

(i) A method of using a terminal group-specific PDCCH

에게

의 값 또는

를 도출할 수 있는 정보를 전송하기 위해 동일 단말 그룹에 속한 단말

에 대한 하향링크 채널과 서로 동일한 하향링크 채널을 이용할 수 있다. 예를 들어,

의 값 또는

를 도출할 수 있는 정보는 전파 지연 또는 기지국이 측정한 송수신 시차(Rx-Tx timing difference)일 수 있다.In the case of multicast, the base station is the terminal

to

the value of or

A terminal belonging to the same terminal group in order to transmit information that can derive

It is possible to use the same downlink channel as the downlink channel for . E.g,

the value of or

The information that can be derived may be a propagation delay or a transmission/reception time difference (Rx-Tx timing difference) measured by the base station.

Method 3-1: The base station may indicate to each terminal the radio identifier of the terminal group through higher layer signaling.

에게 DCI를 할당하고, DCI를 스크램블링할 때 단말 그룹

의 라디오 식별자를 적용할 수 있다. 단말 그룹

에 속한 단말

에게 필요한 정보(즉,

의 값 또는

를 도출할 수 있는 정보)는 DCI에 포함될 수 있다.The base station is a group of terminals

When allocating DCI to and scrambling DCI, the terminal group

A radio identifier of can be applied. terminal group

terminal belonging to

information necessary for you (i.e.,

the value of or

information that can be derived) may be included in DCI.

에 속한 단말

는 지시된 탐색 공간에서 DCI를 검출하여 지시된 라디오 식별자로 디스크램블링을 수행할 수 있다.The UE may be instructed with a radio identifier and a search space for receiving the corresponding DCI through higher layer signaling. terminal group

terminal belonging to

may detect DCI in the indicated search space and perform descrambling with the indicated radio identifier.

에 속한 단말

에게 필요한 정보(즉,

의 값 또는

를 도출할 수 있는 정보)를 포함할 수 있다.Method 3-2: A specific field of DCI is a terminal group

terminal belonging to

information necessary for you (i.e.,

the value of or

information that can be derived).

에게 필요한 정보(즉,

의 값 또는

를 도출할 수 있는 정보)의 위치가 상위계층 시그널링으로 지시될 수 있다.Method 3-3: When performing method 3-2, the terminal in the corresponding DCI

information necessary for you (i.e.,

the value of or

The location of information that can derive ) may be indicated by higher layer signaling.

는 DCI를 검출하고, 특정한 필드의 위치에서 필요한 정보를 얻을 수 있다.terminal

can detect DCI and obtain necessary information from the position of a specific field.

가

의 값 또는

를 도출할 수 있는 정보에 대한 HARQ-ACK의 전송을 위해 사용할 PUCCH의 자원에 대한 정보를 포함할 수 있다.Method 3-4: When performing method 3-2, DCI is

go

the value of or

It may include information on the resource of the PUCCH to be used for transmission of the HARQ-ACK for the information from which it can be derived.

In order for the UE to transmit the PUCCH, the resource index of the PUCCH must be known to the UE. In addition, timing of HARQ-ACK, transmission power of PUCCH, etc. must be known to each UE. Although the value(s) indicated by other field(s) of DCI can be commonly used by terminals belonging to a terminal group, the resource index applied to the PUCCH should be indicated with a unique value for each terminal.

는 DCI에서 지시하는 PUCCH의 자원을 이용해서 HARQ-ACK을 전송할 수 있다. 따라서, 방법 3-4에 의하면, 단말은 DCI를 복호한 결과에 따른 HARQ-ACK을 PUCCH(또는 PUSCH)를 통해 전송할 수 있다. DCI를 복호하기 위해서 블라인드 복호(blind decoding)가 수행하기 때문에, 단말은 DCI를 디스크램블링하는 과정에서 NACK이 도출되면 해당 DCI를 더 이상 복호하지 않을 수 있다. DCI를 디스크램블링하는 과정에서 ACK이 도출되면, 단말은 해당 DCI에 대한 복호가 성공하였음을 알 수 있다. 따라서 단말은 ACK을 도출하여 PUCCH(또는 PUSCH)를 통해 ACK을 전송할 수 있다. 기지국은 단말로부터 ACK이 수신되면, 단말이 DCI에서 해당 정보(즉,

의 값 또는

를 도출할 수 있는 정보)를 성공적으로 복호한 것으로 간주할 수 있다.If DCI does not allocate TB, the terminal

may transmit HARQ-ACK using the resource of PUCCH indicated by DCI. Therefore, according to Method 3-4, the UE may transmit the HARQ-ACK according to the DCI decoding result through the PUCCH (or PUSCH). Since blind decoding is performed to decode the DCI, when a NACK is derived in the process of descrambling the DCI, the UE may not decode the corresponding DCI anymore. When the ACK is derived in the process of descrambling the DCI, the UE can know that the decoding of the DCI has been successful. Accordingly, the UE may derive the ACK and transmit the ACK through the PUCCH (or PUSCH). When the base station receives an ACK from the terminal, the terminal receives the corresponding information in DCI (that is,

the value of or

information that can be derived) can be considered to have been successfully decoded.

의 값 또는

를 도출할 수 있는 정보)를 성공적으로 복호한 것으로 간주할 수 있다.When DCI allocates a TB, the UE may transmit HARQ-ACK using the resource of PUCCH indicated by DCI. Therefore, according to Method 3-4, the UE may receive the PDSCH in the resource indicated by the DCI, and transmit the HARQ-ACK according to the result of decoding the TB through the PUCCH (or PUSCH). The UE may derive ACK or NACK according to the TB decoding result. Since the base station can interpret that the terminal has successfully received DCI when ACK or NACK is received from the terminal, the terminal receives the corresponding information included in the DCI (that is,

the value of or

information that can be derived) can be considered to have been successfully decoded.

(ii) a method of using a terminal group-specific PDSCH

의 값 또는

를 도출할 수 있는 정보를 모두 포함할 수 있다. 소정의 단말들은 동일한 하향링크 채널을 수신하며, 각 단말에 대한 정보를 하향링크 채널로부터 획득할 수 있다.In the case of multicast, the base station may transmit one downlink channel to predetermined terminals (eg, terminals belonging to a terminal group). The downlink channel is for certain terminals.

the value of or

It can include all information that can be derived. Certain terminals receive the same downlink channel, and information about each terminal can be obtained from the downlink channel.

Method 3-5: A separate radio identifier is allocated to the terminal group, and the terminal group may utilize the radio identifier to receive a downlink channel.

The base station may set the radio identifier to the predetermined terminals through higher layer signaling in order to designate the predetermined terminals as one group.

The reference time (eg, UTC) may be included in a MAC service data unit (SDU) and indicated to the UE group using an RRC message. Also, an offset to be applied to terminals belonging to a terminal group may be indicated using MAC CE. When the base station generates a MAC (sub)PDU, the MAC SDU and the MAC CE may be multiplexed and transmitted through the PDSCH.

에 대한

의 값 또는

를 도출할 수 있는 정보)만으로 MAC CE가 각 단말에 대해서 생성되고, 단말들을 위한 MAC CE들이 다중화되어 MAC PDU가 생성될 수 있다.Alternatively, an offset required for each terminal belonging to a terminal group (eg, a terminal

for

the value of or

MAC CE may be generated for each UE only with information that can derive

Method 3-6: The offset for the terminal and/or identification information of the terminal is included in the MAC CE.

를 위한 옵셋을 식별하기 위한 방법이 필요하다. 방법 3-6에 의하면, 단말의 식별정보와 옵셋이 함께 MAC CE에 포함된다. Among the terminals belonging to the terminal group, a specific terminal

A method for identifying an offset for According to method 3-6, the identification information of the terminal and the offset are included in the MAC CE together.

8 and 9 are conceptual diagrams for explaining an example of MAC CEs including an offset.

Referring to FIG. 8 , a TAG ID and an offset (ie, an offset command) for estimating a downlink propagation delay are included in the MAC CE, and additionally, identification information (ie, RNTI) of the UE is included in the MAC CE. Here, Octet x, Octet x+1, and Oct x+2 do not necessarily have this order. If the offset means TAC, Octet x of FIG. 8 may be the same as Octet 1 of FIG. 6 .

Referring to FIG. 9 , including the offset for estimating the downlink propagation delay and identification information (ie, RNTI) of the terminal is the same as in the example of FIG. 8 . If the offset means TAC, Octet x of FIG. 9 may be the same as Octet 1 of FIG. 7 .

8 and 9 , the RNTI may be included in the MAC CE as identification information of the UE. For example, when the terminal establishes an RRC connection with the base station, the identification information of the terminal may be C-RNTI, MCS-C-RNTI, or CS-RNTI. For example, when the terminal does not establish an RRC connection with the base station, the identifier of the terminal may be a temporary cell (TC)-RNTI. Since the RNTI is expressed in 16 bits, in the MAC CEs of FIGS. 8 and 9, the RNTI is expressed as two octets (ie, Octet x+1 and Octet x+2).

를 식별하는 별도의 식별자(예컨대, 그룹 멤버 ID)가 존재하는 경우에는 해당 식별자가 RNTI를 대신하여 MAC CE에 포함될 수 있다. 이 경우, 해당 식별자는 단말의 RNTI로부터 도출될 수 있다.terminal in terminal group

If there is a separate identifier (eg, group member ID) for identifying the RNTI, the corresponding identifier may be included in the MAC CE instead of the RNTI. In this case, the corresponding identifier may be derived from the RNTI of the terminal.

Using Method 3-6, even terminals that are located sufficiently close to the base station (eg, within 100 m) and do not need compensation for downlink propagation delay can receive the MAC (sub)PDU. For example, DCI and/or PDSCH may be scrambled with the RNTI allocated to the UE group. When a terminal belonging to a terminal group checks its identification information in the received MAC CE, an offset corresponding to its identification information can be obtained. On the other hand, if the terminal belonging to the terminal group does not check its identification information in the received MAC CE, it may be determined that the offset is unnecessary for itself.

In the MAC CEs of FIGS. 8 and 9 , an offset may mean a TAC.

(4) A method of indicating an offset based on a single closed loop

In a time-sensitive network, the base station transmits the reference time (eg, UTC) to the terminal in the MAC SDU, and the terminal interprets this to compensate for the time when the MAC SDU is received (that is, the delay time caused by the reception of the PDSCH). can That is, the terminal can estimate the effect of the downlink propagation delay.

The offset (eg, TA or RTT) managed by the base station for each terminal means the sum of the downlink propagation delay and the uplink propagation delay. When the uplink and downlink frequency gap (duplex gap) is sufficiently small (ie, when the duplex gap is small while operating in TDD or FDD), the downlink propagation delay and the uplink propagation delay may have similar values. In this case, the downlink path delay can be obtained from the offset. Therefore, method 4-1 can be used.

을 차감한 값의 절반을 하향링크 전파 지연으로 해석할 수 있다.Method 4-1: If the offset is TA, the terminal is in the TA

Half of the value obtained by subtracting ? can be interpreted as downlink propagation delay.

Meanwhile, in a system operating with FDD, when the duplex gap is quite large, the downlink propagation delay and the uplink propagation delay may not be the same. In this case, if the method 4-1 is applied, the downlink propagation delay may be incorrectly estimated. However, it is possible to reduce the error to a desired amount by more accurately managing the TA.

In order to more accurately estimate the downlink propagation delay, the base station may instruct the terminal to interpret the TAC for managing the TA in more granular units. If the TAC has a more granular unit, since the terminal has a more granular TA, the terminal can more accurately estimate the downlink propagation delay. Therefore, a method for the base station to indicate the unit of the TAC to the terminal may be required.

Method 4-2: The base station may indicate the unit of TAC to the terminal through RRC signaling.

또는 별도의 시그널링이 없을 때 적용하는 기본값)로 동작할 수 있다. 기지국이 시간 민감 네트워크에 관련된 시나리오에 따라 동작하는 경우에는, 기지국은 단말에게 RRC 시그널링을 통해서 TAC의 단위2를 지시할 수 있다. TAC의 단위2는 TAC의 단위1보다 더 세밀한 단위일 수 있다. 기지국은 MAC CE를 이용해서 단말에게 TAC를 지시할 수 있고, 단말은 RRC 시그널링에 따라 TAC의 단위1 또는 단위2를 수신된 TAC에 적용할 수 있다.The base station may indicate the unit of TAC by RRC signaling to the terminal. When the base station does not operate according to a scenario related to a time-sensitive network, the base station may not perform separate RRC signaling to the terminal. The terminal is the unit 1 of the TAC (that is, a value determined in the technical standard, for example,

Alternatively, it may operate as a default value applied when there is no separate signaling). When the base station operates according to a scenario related to a time-sensitive network, the base station may indicate the TAC unit 2 to the terminal through RRC signaling. The unit 2 of the TAC may be a finer unit than the unit 1 of the TAC. The base station may instruct the terminal to TAC by using the MAC CE, and the terminal may apply unit 1 or unit 2 of the TAC to the received TAC according to RRC signaling.

Using method 4-2, the time point at which the unit change of TAC according to RRC signaling is applied is immediately after the UE transmits the ACK to the base station using PUCCH (or PUSCH) or a predetermined time has elapsed from the transmission time of the corresponding ACK. may be later. Alternatively, in order to determine when the unit change of TAC according to RRC signaling is applied, the UE may need to transmit separate RRC signaling to the base station. The reason is that a response (eg, ACK) to RRC signaling may also be transmitted through RRC signaling. Alternatively, it may be predetermined that the unit of the TAC is changed when a predetermined time (eg, a time corresponding to a predetermined number of slots) passes in the technical standard.

Method 4-3: An event in which the unit of TAC is changed without separate signaling may be predefined.

If an event in which the unit of TAC is changed is defined, the UE may change the unit of TAC from unit 1 to unit 2 or from unit 2 to unit 1 from the time of occurrence of the corresponding event or a predetermined time from the time of occurrence of the event. have.

For example, at the time when the procedure of initial access is completed (that is, when it is determined that decoding of the M4 PDSCH is successful), the UE may change the TAC unit from unit 1 to unit 2 or from unit 2 to unit 1 have.

As another example, if the UE performs the procedure of initial access to the same cell again after the UE establishes the RRC connection, the unit of TAC may be changed. For example, when the UE that has set up the RRC connection performs random access, the unit of TAC may be changed to another unit. If the UE performs random access while applying unit 1, it may be interpreted that unit 2 is applied. On the other hand, if the terminal performs random access while applying unit 2, it may be interpreted that unit 1 is applied.

As another example, after the UE establishes the RRC connection, if higher layer signaling instructing the UE to perform a time sensitive service is received from the base station, unit 2 may be applied as a unit of TAC. When not performing the time-sensitive service, the UE applies unit 1, but when instructed to perform the time-sensitive service through higher layer signaling, the UE may apply unit 2.

를 적용하고 있을 때 새로운 TA를 포함한 MAC RAR 또는 MAC CE가 수신되면, 단위

가 적용될 수 있다.As another example, when a new initial value of TA is received from the UE, the unit of TAC may be changed. When the (absolute) value of the TA is transmitted to the UE, the UE may replace the TA with the indicated new value without accumulating and applying the TAC to the stored TA. In this case, the terminal may interpret the indicated value as unit 1 or unit 2. When the MAC RAR shown in FIG. 5A or FIG. 5B or the MAC CE shown in FIG. 7 is received, the UE may calculate a new TA, and at this time, may change the unit of the TAC. That is, the terminal is a unit

When a MAC RAR or MAC CE including a new TA is received when applying

can be applied.

Method 4-4: MAC CE may indicate the unit of TA.

10A, 10B, 11A, 11B, 12A, 12B, 13A, and 13B are conceptual views illustrating structures of a MAC CE including information indicating a unit applied to a TAC.

The MAC CE may indicate not only the TAC but also the unit of the TAC. As in method 4-2, unit 1 or unit 2 for TAC may be indicated by MAC CE. If the MAC CE indicates unit 1 or unit 2, the UE may apply the indicated unit when accumulating the TAC in the TA.

FIG. 10A illustrates a case in which a TAC unit ('U') is included in a MAC CE transmitted through a UE-specific PDSCH, and FIG. 10B is a TAC in a MAC CE transmitted through a UE group-specific PDSCH. A case in which a unit ('U') is included is shown.

The base station may indicate to the terminal whether the MAC CE includes the unit of TAC by RRC signaling. That is, according to RRC signaling, the MAC CE may not include a unit of TAC, and the UE may assume that the unit of TAC is basically designated as unit 1. When the MAC CE is indicated to include the unit of TAC in RRC signaling, the UE may assume that the unit of TAC is given as unit 1 or unit 2 by the MAC CE.

In one example, when the MAC CE includes a unit of TAC, the range of values that the TAC may have may be reduced. Since the MAC CE indicating the TA to the UE has a byte unit size, the number of bits allocated to the TAG ID or TAC may be reduced in order to include information indicating the TAC unit in the MAC CE. When the terminal does not operate based on the time-sensitive service, since the terminal can operate according to a general procedure (ie, unit 1 of TAC), the terminal can assume that TA with a certain degree of accuracy is secured. When the base station instructs the terminal to operate based on the time-sensitive service, even if the range of values that the TAC can have is reduced, a TAC having sufficient accuracy according to unit 2 may be indicated to the terminal.

In one example, when the unit of TAC is included in the MAC CE, the range of values that the TAG ID may have may be reduced. The UE may be configured with up to four TAGs and may manage TAs for each TAG. However, there may be TAGs utilizing up to two time-sensitive services. Therefore, the TAG ID when operating in unit 1 of TA and TAG ID when operating in unit 2 of TA may have different lengths for the UE, and interpretation methods thereof may be different. 11A and 11B , it can be seen that the length of the field indicating the TAG ID is reduced from 2 bits to 1 bit compared to the MAC CEs shown in FIGS. 10A and 10B . That is, it is possible to increase the length of the field indicating the TAC by reducing the length of the TAG ID.

The base station may configure two or less TAGs in which the time-sensitive service is utilized to the terminal. Accordingly, the base station may instruct the terminal to operate TAG(s) based on unit 2 of the TAC through higher layer signaling. Alternatively, if MAC CEs including TAC are multiplexed to MAC SDU including UTC, this MAC CE may be interpreted as having the structure shown in FIG. 11A or 11B. For example, when the TAG ID is a or b, the unit of the TAC may follow the unit indicated by the MAC CE.

Method 4-5: When method 4-4 is applied, the unit of TA may be indicated using the reserved bit of the MAC CE.

When the MAC CE includes the unit of the TAC, a reserved bit may be used to maintain the range of values that the TAC may have. Referring to the structures of the MAC CE shown in FIGS. 12A and 12B , in a MAC CE having a length of 2 bytes, the TAC is represented by 12 bits and a unit of the TAC (ie, 'U') using some of the remaining bits. may be indicated. More specifically, the unit of TAC may be indicated by using one bit among four bits given as reserved bits in the MAC CE structure shown in FIG. 7 .

When the MAC CE includes the unit of the TAC, a reserved bit may be used to maintain the range of values that the TAC may have. Referring to the structures of the MAC CE shown in FIGS. 13A and 13B , in a MAC CE having a length of two bytes, the TAC is represented by 12 bits, and a TAG ID to which the TAC is additionally applied may be included. More specifically, in the MAC CE structure shown in FIG. 7, a unit of TAC may be indicated using one bit among four bits given as reserved bits, and a TAG ID may be indicated using two bits.

Meanwhile, information indicating a unit applied to the TAC may be included in the MAC RAR instead of the MAC CE.

14A and 14B are conceptual diagrams illustrating structures of a MAC RAR including information indicating a unit applied to a TAC according to an embodiment of the present invention.

When the MAC CE includes the unit of the TAC, a reserved bit may be used to maintain the range of values that the TAC may have. Referring to the MAC RARs shown in FIGS. 14A and 14B , the TAC is represented by 12 bits, and the unit of the TAC may be indicated using a bit given as a reserved bit in the MAC RAR structure shown in FIGS. 5A and 5B .

Method 4-6: A combination of a TAG ID and a TAC unit may be indicated as an index.

Since the time-sensitive service does not need to be performed for all TAGs, the units of the TAG ID and TAC may be compressed and expressed. To this end, the base station may indicate to the terminal that the index for the combination of the TAG ID and the TAC unit may be indicated by higher layer signaling.

When the index indicated through the MAC CE is expressed by, for example, 2 bits, the base station may instruct the terminal to interpret the method according to the index through higher layer signaling.

15 is a conceptual diagram for explaining a case of indexing combinations of TAG ID and TAC units.

Referring to FIG. 15 , the range of the TAG ID may be indicated by higher layer signaling. For example, up to four TAGs may be supported. Referring to FIG. 15 , unit 1 or unit 2 may be applied as a unit of TAC.

Method 4-7: When a serving cell or TAG in which a time-sensitive service is utilized is fixed to one, unit 2 may be applied as a unit of TAC without separate signaling from the base station.

One serving cell in which a time-sensitive service is utilized may be fixed. For a serving cell that transmits a MAC (sub)PDU including a reference time (eg, UTC), one TAG ID to which an uplink carrier for the corresponding serving cell belongs may be determined. In this case, the TAC included in the MAC CE indicated by the ID of the corresponding TAG may be interpreted by applying unit 2. Therefore, without separate explicit signaling from the base station, the terminal may interpret the TAC unit as unit 2. For example, if it is assumed that the time-sensitive service is utilized only in the TAG corresponding to a specific TAG ID (eg, 2), it may be assumed that unit 2 is applied to the TAC included in the MAC CE indicated by the TAG ID 2 .

(5) Method of estimating propagation delay based on multiple closed loops

In order to support a time-sensitive service, it may not be necessary for the UE to maintain its TA in detail. This is because, in the time-sensitive service, the basic purpose is for the terminal to receive a reference time (eg, UTC) from the base station and to compensate for the downlink propagation delay. Also, a method of estimating the downlink propagation delay by half of the TA may have a large error according to the duplex gap. In addition, since the shared time may exist in the terminal or the base station, the downlink propagation delay and the uplink propagation delay may need to be distinguished according to the subject having the shared time. However, in general, since the downlink propagation delay and the uplink propagation delay do not differ greatly, they may be regarded as having the same value.

에게 TAC를 지시하기 위한 종래의 폐루프를 그대로 유지하면서 추가적인 폐루프를 도입할 수 있다. 추가적인 폐루프는 TAC를 지시하거나 또는 전파 지연(

)을 추정할 수 있는 옵셋(예컨대, RTT 또는 Rx-Tx time difference로부터 도출된 옵셋)을 지시할 수 있다.base station is the terminal

An additional closed loop can be introduced while maintaining the conventional closed loop for instructing TAC to the user. An additional closed loop indicates TAC or propagation delay (

) may indicate an offset (eg, an offset derived from RTT or Rx-Tx time difference) that can be estimated.

Since the terminal supporting the time-sensitive service uses the existing closed loop as it is and utilizes the added closed loop, compatibility of technical standards can be maintained. Here, the offset (eg, TAC or RTT or Rx-Tx time difference) indicated to the UE may be included in UE-specific DCI, UE-specific PDSCH, UE group-specific DCI, or UE group-specific PDSCH. have.

Method 5-1: TAC may be indicated in the additional closed loop, and a more granular unit than the TAC indicated by the conventional closed loop may be applied to the TAC indicated by the additional closed loop.

The UE may be instructed to two closed loops for managing the TAC. One closed loop 1 may be used to indicate to the UE a TAC to which a general unit (ie, unit 1) is applied, and the other closed loop 2 is a TAC to which a more detailed unit (ie, unit 2) is applied to the UE. can be used to instruct Here, unit 2 may be indicated to the UE by higher layer signaling.

As an example, the UE may derive a TA by accumulating the TACs obtained in the closed loop 1 and the closed loop 2. The derived TA may be utilized when the UE performs uplink transmission, and may be utilized for the UE to estimate propagation delay. The propagation delay may be determined from the derived TA.

As another example, the UE may derive the TA by accumulating at least the TAC obtained in closed loop 1. The derived TA may be utilized when the terminal performs uplink transmission. However, the TAC obtained in closed loop 2 may not be reflected in the TA for uplink transmission. The base station should maintain the period of closed loop 1 so that only closed loop 1 can guarantee orthogonality of uplink transmission. That is, the additional closed loop 2 may not be forced to be reflected in the TA. One implementation of the terminal may derive the TA by using both closed loop 1 and closed loop 2, and another implementation of the terminal may derive the TA by using only closed loop 1. Although closed loop 2 is not utilized for uplink transmission, it may be utilized to estimate downlink propagation delay. That is, the UE accumulates each TAC obtained from the closed loop 1 and the closed loop 2 to obtain one TA value, and the obtained TA value is used to determine the downlink propagation delay.

Method 5-2: An additional closed loop may indicate an offset for estimating propagation delay.

One closed loop for managing TAC is given to the UE, and the other closed loop may indicate an offset for compensating for propagation delay. The UE may estimate the downlink propagation delay from the TA with a predetermined accuracy, and may more accurately estimate the downlink propagation delay using the additionally instructed offset.

An example of such an offset may be RTT or Rx-Tx time difference. The UE estimates TA in a closed loop and may estimate RTT by receiving an RTT instruction in an additional closed loop or receiving an Rx-Tx time difference. When estimating RTT using TA, for estimating RTT As an alternative TA, a value estimated by the UE as one of the closed loops may be applied.

(6) A method of using a terminal-specific uplink channel

에게

의 값 또는

를 도출할 수 있는 정보를 단말-특정적 PDSCH에 포함하여 전송할 수 있다. 한편, 단말

가

의 값 또는

를 도출할 수 있는 정보를 기지국으로 보고할 수 있다. 이는 PUSCH를 이용한 보고를 의미하고, 방법 6-1로서 후술된다.The UE may transmit or receive RTT or Rx-Tx time difference or TA with the base station. As presented in method 3-6, the base station is

to

the value of or

Information for deriving ? may be transmitted by being included in the UE-specific PDSCH. On the other hand, the terminal

go

the value of or

It is possible to report to the base station information that can be derived. This means reporting using PUSCH, which will be described later as Method 6-1.

에 대한

의 값 또는

를 도출할 수 있는 정보) 만을 포함한 MAC CE가 생성되고, MAC CE는 MAC (sub)PDU에 포함될 수 있다.Method 6-1: Offset required for a terminal belonging to a terminal group (eg, terminal

for

the value of or

A MAC CE including only information that can derive

Here, the MAC CE may follow the structures described above.

로부터 수신한 정보를 이용하여 전파 지연을 보상할 수 있다. 이는 단말

가 공유하는 시간을 기지국에서 수신하고 기지국에서 전파 지연을 보상하여 수신을 수행하는 경우에 활용될 수 있다. 또한, 기지국이 공유하는 시간을 단말

에서 수신하고 기지국에서 전파 지연을 보상하여 전송을 수행하는 경우에 활용될 수 있다.base station is the terminal

Propagation delay can be compensated using information received from this is the terminal

It can be utilized when the base station receives the time shared by , and the base station performs reception by compensating for propagation delay. In addition, the time shared by the base station is

It can be utilized when receiving from and performing transmission by compensating for propagation delay in the base station.

(7) HARQ-ACK transmission method

에 대한

의 값 또는

를 도출할 수 있는 정보)를 MAC (sub)PDU에서 얻을 수 있다고 가정할 수 있다. 하지만, 시간 민감 서비스는 매우 낮은 오류율을 요구할 수 있기 때문에 단말이 명시적으로 예컨대, 단말

에 대한

의 값 또는

를 도출할 수 있는 정보에 대한 HARQ-ACK을 기지국으로 피드백하는 것이 바람직할 수 있다.Since the MAC (sub)PDU generated by the base station is received by multiple terminals, the terminal may generate an HARQ-ACK for it, but may not feed it back to the base station. The terminal has sufficient information to correct the downlink propagation delay with respect to the reference time (eg, the terminal

for

the value of or

It can be assumed that information that can derive ) can be obtained from the MAC (sub)PDU. However, since the time-sensitive service may require a very low error rate, the terminal explicitly

for

the value of or

It may be desirable to feed back HARQ-ACK for information capable of deriving HARQ-ACK to the base station.

Method 7-1: MAC CE may include information on resources of PUCCH for transmission of HARQ-ACK.

When the base station transmits the PDSCH, the base station may indicate to the terminal the resource index of the PUCCH for transmitting the HARQ-ACK through scheduling DCI, activating DCI, or RRC signaling. Since the base station can transmit the PDSCH to several terminals, it is preferable for the base station to indicate a unique PUCCH resource to each terminal.

In order to indicate the resource of the PUCCH, it is preferable that the base station indicates the offset of the slot for transmitting the PUCCH, the resource index of the PUCCH, or the transmission power control index of the PUCCH to the terminal. In some cases, an offset or an index indicated by DCI may be reused.

Method 7-2: When method 7-1 is applied, the MAC CE may include at least the resource index of the PUCCH.

When the terminal receives the MAC (sub)PDU generated by the base station, the terminal can generate a HARQ-ACK for it and feed it back to the base station, and the resource index of the PUCCH including the HARQ-ACK is at least the PRI included in the MAC CE. (PUCCH resource indicator) may be determined using. Alternatively, DCI may include PRI.

Method 7-3: When method 7-2 is applied, the PUCCH resource may be determined only by the PRI indicated by the MAC CE without using the PRI included in the DCI field.

The PRI included in the field of DCI may not be used. According to method 7-3, MAC CE includes PRI and RNTI, and an offset for reference time is included. When the UE receives the PDSCH and checks the MAC CE including the unique C-RNTI, MCS-C-RNTI, CS-RNTI, or TC-RNTI, the PUCCH resource is used using the PRI included in the MAC CE. can decide

Meanwhile, according to the conventional technical standard, when the first set of PUCCH resources has 8 or more elements, the index of the first CCE to which DCI is mapped is utilized together with the PRI to determine the resource of the PUCCH. When the same DCI is transmitted to multiple terminals, since the CCEs to which the DCI is mapped are the same for the terminals, separate information must be provided to the terminals in order to indicate different PUCCH resources to the terminals.

Method 7-4: When method 7-2 is applied, PRI is applied to determine the resource index of PUCCH regardless of the number of resources belonging to the first set of resources of PUCCH.

Meanwhile, in order to indicate the slot in which the HARQ-ACK is transmitted, an offset based on the slot in which the PDSCH is received may be indicated to the UE. According to the conventional technical standard, the offset of the slot in which the HARQ-ACK is transmitted can be indicated in the DCI to which the PDSCH is allocated. However, the offset of the slot in which the HARQ-ACK is transmitted may not be included in the DCI. In this case, in order for the UE to apply the method 7-1, the MAC CE must include an offset (or timing) of a slot for the UE to transmit the HARQ-ACK.

Method 7-5: When method 7-1 is applied, the MAC CE may include offset information of a slot for transmitting HARQ-ACK.

If method 7-5 is not applied, information on a slot for transmitting HARQ-ACK may not be included in the MAC CE. In this case, the UE may derive a slot for transmitting the PUCCH by applying the offset of the slot indicated by DCI or the offset of the slot indicated by higher layer signaling.

When transmitting the PUCCH, a transmit power control (TPC) command to be applied by the terminal should be indicated. The terminal may receive transmission power indicated by the base station in a separate DCI. For example, the PUCCH TPC command may be periodically indicated by DCI format 2_2. The UE may receive an additional TPC command through the MAC CE. The reason is that the reception performance of the base station can be improved by adjusting the transmission power of the PUCCH not only when the base station transmits DCI but also when the base station transmits the PDSCH.

Method 7-6: When method 7-1 is applied, the TPC command for controlling the transmission power of the PUCCH may be additionally included in the MAC CE to be instructed to the UE.

16A to 16D and 17A to 17D are conceptual diagrams for explaining structures of a MAC CE including information for HARQ-ACK transmission.

16A to 16D and 17A to 17D , structures of MAC CEs to which all of the above-described methods are applied are shown. If the MAC CE is transmitted in the UE-specific downlink channel, the MAC CE does not need to include the identifier of the UE, but if the MAC CE is transmitted in the UE group-specific downlink channel, the MAC CE may include the identifier of the UE. can

The size of the field(s) required to express the resource of the PUCCH may be determined by a technical standard or higher layer signaling. 16A to 16D and 17A to 17D, TPC to be applied to PUCCH is expressed with 2 bits, PDSCH-PUCCH timing is expressed with 3 bits, and the resource index of PUCCH is expressed with 4 bits. However, embodiments of the present invention are not limited thereto.

The MAC CE is byte-aligned, and when the field(s) included in the MAC CE is less than 8 bits, reserved bits may be inserted as needed.

16A, 16C, 17A, and 17C are structures in which the TAC or offset unit ('U') required for each UE is not separately indicated. 16B, 16D, 17B, and 17D are structures in which a TAC or an offset unit required for each UE is included in the MAC CE and indicated. If a TAG ID is required, the TAG ID may be included in the MAC CE. When the TAG ID is unnecessary, the TAG ID may not be included in the MAC CE.

(8) application reference time

If the mobility of the UE or the closed-loop period for managing the TA is not appropriate, the TA of the UE may have a fairly large relative error. According to the technical standard, in the process of managing the TA, the terminal may calculate the relative accuracy of the TA. The reason for calculating the relative accuracy is for the UE to change the TA by itself when the value of the TA changes too much. When the UE observes an error greater than or equal to the reference value, the UE increases or decreases the TA so that the relative error of the TA is maintained below the reference value. According to the technical standard, the standard value that the relative accuracy of TA should have is presented. When Method 8-1, which will be described later, is applied, since the base station needs to properly manage the TA, there is no need for the terminal to calculate the relative error of the TA.

Method 8-1: The base station may instruct (or set) with higher layer signaling so that the terminal does not adjust the TA by itself.

When the terminal is allowed to change the TA arbitrarily, the base station may set the terminal not to change the TA by itself, because the base station cannot know the exact value of the TA. Accordingly, when method 8-1 is applied, the burden on the control for managing TAs for all terminals belonging to the terminal group may be large on the base station.

가 스스로 TA를 관리할 수 있도록 허용하되, 기지국과 단말

가 동일한 TA를 공유하는 것이 바람직하다.To compensate for this, the base station

Allow the TA to manage itself, but the base station and the terminal

preferably share the same TA.

Method 8-2: Upon receiving the TAC or the offset for the propagation delay, the terminal estimates the propagation delay from the estimate of the TA or the path delay of the terminal at the reference time (T).

Method 8-3: In method 8-2, the reference time T may be a symbol or (sub/mini) slot of an uplink signal or channel last transmitted by the terminal to the base station.

가 기지국으로부터 수신한 TA의 값, 전파 지연, 또는 전파 지연을 도출할 수 있는 옵셋(

) 또는 RTT 또는 Rx-Tx time difference을 적용하는 기준 시점 또는 기준 TA가 필요하다. 단말

는 시점(T)에서의 전파 지연에 대한 추정치 또는 TA의 값을 저장할 수 있다. 기준이 되는 시점(T)와 무관하게, 단말

는 지속적으로 TA를 스스로 변경할 수 있도록 허용될 수 있다.terminal

An offset from which the value of TA received from the base station, propagation delay, or propagation delay

) or a reference time or reference TA applying RTT or Rx-Tx time difference is required. terminal

may store an estimate of the propagation delay at time T or the value of TA. Regardless of the reference time (T), the terminal

may be allowed to continuously change the TA itself.

는 기준 시점(T) 이후에 스스로 변경한 TA를 제외하고, 기지국으로부터 수신한 TAC, TA, 또는 옵셋 또는 RTT 또는 Rx-Tx time difference를 이용해서 전파 지연을 추정할 수 있다. 기준 시점(T)는 단말

가 기지국에게 마지막으로 전송한 SRS, PRACH 프리앰블, PUSCH, 또는 PUCCH가 포함된 시간 자원일 수 있다. TA를 이용한 방법을 적용하는 경우, 기지국은 상향링크 신호 또는 채널을 수신해서 단말

가 가지는 TA를 추정하지만, 특정한 상향링크 신호 또는 채널 만으로 TA가 도출하도록 기술규격에서 한정하지 않기 때문이다.terminal

can estimate the propagation delay using the TAC, TA, or offset or RTT or Rx-Tx time difference received from the base station, except for the TA changed by itself after the reference time T. The reference time (T) is the terminal

It may be a time resource including the last SRS, PRACH preamble, PUSCH, or PUCCH transmitted to the base station. When the method using TA is applied, the base station receives an uplink signal or channel and receives the terminal

This is because the technical standard does not limit the TA to be derived only with a specific uplink signal or channel, although the TA of .

(9) A method of measuring the difference between the reception times of the reference signal

의 값 또는

를 도출할 수 있는 정보)를 지시받을 수 있다.

의 값 또는

를 도출할 수 있는 정보는 PDSCH 또는 PUSCH를 통해 전달될 수 있다. 또는,

의 값 또는

를 도출할 수 있는 정보는 단말(또는 기지국)에 의해 암시적으로 추정될 수 있다.When the TA or RTT or Rx-Tx time difference is estimated in the terminal or the base station, the time difference (

the value of or

information that can be derived) can be instructed.

the value of or

Information for deriving ? may be transmitted through PDSCH or PUSCH. or,

the value of or

Information capable of deriving ? may be implicitly estimated by the terminal (or base station).

의 값 또는

를 도출할 수 있는 정보가 암시적으로 단말(또는 기지국)에 의해 추정되기 위해서, 참조신호가 수신되는 시점들의 차이를 측정하는 것이 바람직하다. 종래의 기술규격에 의하면, 2개의 TRP들(또는 기지국들)로부터의 참조신호들이 수신되는 시점들의 차이를 단말이 측정할 수 있다. 보다 구체적으로, 단말은 하향링크 참조신호(예컨대, CSI-RS, 하향링크 PRS, 또는 SS/PBCH 블록)가 TRP i와 TRP j로부터 수신되는 시점들의 차이를 측정할 수 있다. 단말은 TRP i로부터 하향링크 참조신호를 수신한 하향링크 슬롯(또는, 서브프레임 또는 심볼)의 경계(T_i)를 도출하고, TRP j로부터 하향링크 참조신호를 수신한 하향링크 슬롯(또는, 서브프레임 또는 심볼)의 경계(T_j)를 도출하고, 이들 간의 시간 차이를 측정할 수 있다. 여기서 TRP i는 기준이 되는 TRP로써, 단말이 측정하는 값은 (Tj-Ti)일 수 있다. 여기서, 하향링크 슬롯은 TRP i 및 TRP j에게 공통으로 해석되는 가상의 슬롯(또는 기준 슬롯)으로써, 동일한 슬롯을 의미할 수 있다.

the value of or

In order to implicitly estimate by the terminal (or the base station) the information from which the reference signal is received, it is preferable to measure the difference between the time points at which the reference signal is received. According to the prior art standard, the terminal can measure the difference between the time points at which the reference signals from the two TRPs (or base stations) are received. More specifically, the UE may measure the difference between the time points at which the downlink reference signal (eg, CSI-RS, downlink PRS, or SS/PBCH block) is received from TRP i and TRP j. _{The terminal derives the boundary (T i} ) of the downlink slot (or subframe or symbol) that receives the downlink reference signal from TRP i, and receives the downlink reference signal from TRP j in the downlink slot (or sub-frame) the boundaries (T _j) of the frame or symbols) can be derived and measuring the time difference between them. Here, TRP i is a reference TRP, and the value measured by the terminal may be (Tj-Ti). Here, the downlink slot is a virtual slot (or reference slot) interpreted in common to TRP i and TRP j, and may mean the same slot.

In this way, the time difference calculated by the terminal to calculate the distance between the two TRPs is reported to the base station. In order to estimate the propagation delay, the UE needs to measure the time difference, but the conventional method is insufficient. When TRP i and TRP j are the same TRP, that is, when a downlink reference signal from one TRP is received at two or more time points in the terminal (eg, when received through two or more paths), the terminal is downlinked In order to derive a more accurate boundary of one downlink slot (or subframe or symbol), it is not considered that the boundary of the downlink slot (or subframe or symbol) receiving the link reference signal is two or more. This is because the reception result of the link reference signal is used (eg, averaged). Therefore, in order to derive two reception times at which the downlink reference signal from the same TRP is received to the terminal, the base station needs to provide separate signaling to the terminal.

(또는 단말

가 속한 단말 그룹)에 대해서, 기지국은 하향링크 참조신호를 전송하여, 단말

에서 수신 시간의 차이를 추정할 수 있다.terminal

(or terminal

for the terminal group to which the base station belongs), the base station transmits a downlink reference signal to the terminal

can estimate the difference in reception time.

18 is a conceptual diagram for explaining a difference between boundaries of downlink slots derived from reception times of a downlink reference signal.

Method 9-1: The downlink reference signal is newly received from the same TRP (or base station) as _{the boundary (T 0} ) of the downlink slot derived at the time when the downlink reference signal is previously received from the same TRP (or base station) _{The difference between the boundary (T 1} ) of the downlink slot derived at the time may be measured.

Referring to FIG. 18 , when the terminal receives a previous downlink reference signal from the base station (or TRP), it may be assumed that _{the boundary of the downlink slot estimated (or estimated) by the terminal is T 0 .} The terminal may again receive the downlink reference signal from the base station (or TRP) to estimate the boundary of the downlink slot, and the estimated boundary of the downlink slot may be referred to _{as T 1 .} In this case, the terminal may _{derive (T 1} - T ₀ ). For convenience of description, it can be expressed that RSTD (RS timing difference) of the same TRP is measured.

The UE determines the boundary between the TRP (or base station) and the downlink slot that transmitted the downlink reference signal (ie, downlink PRS, SS/PBCH block, or CSI-RS) used when deriving the boundary of the downlink slot before. It can be assumed that the TRPs (or base stations) that transmit the downlink reference signals used for the new derivation are the same. The UE may newly derive the boundary of the downlink slot even for the same TRP. Since this is performed for a single TRP, it is different from the procedure for measuring the downlink RSTD. Even if the terminal newly derives the boundary of the downlink slot using the downlink reference signal, the terminal may not apply the newly derived boundary when receiving the downlink slot.

에게 기준이 되는 시점(T)을 공유하는 경우, 단말

는 수신한 시점에 대해 새로 도출한 하향링크 슬롯의 경계와 기존의 하향링크 슬롯의 경계의 차이(T₁ - T₀)를 보정할 수 있다. 또는 단말은 T₁과 T₀을 각각 도출할 수 있다. 이 때, 단말

는 하향링크 슬롯의 경계를 관리하면서, 하향링크 전파 지연(

)을 이미 알고 있으므로, T₁ - T₀를 더욱 고려하면 보다 정확한 시간이 얻어질 수 있다. 단말은 동일 TRP에 대한 RSTD를 기지국으로 보고할 필요가 없을 수 있다.Terminal in TRP

In the case of sharing the reference point (T) to

can correct _{the difference (T 1} - T ₀ ) between the boundary of the newly derived downlink slot and the boundary of the existing downlink slot with respect to the received time point. Alternatively, the UE may _{derive T 1} and T ₀ , respectively. At this time, the terminal

while managing the boundary of the downlink slot, the downlink propagation delay (

), a more accurate time can be obtained by further considering _{T 1} - T _{0 .} The UE may not need to report the RSTD for the same TRP to the base station.

If the base station compensates for the propagation delay in advance and transmits it to the terminal, an RSTD for the same TRP may be required. When the UE is configured to measure and report the downlink RSTD to the base station, the UE may measure the RSTD for the same TRP as well as the RSTD for another TRP and report it to the base station.

Method 9-2: When the base station instructs (or configures) the UE to measure the downlink RSTD by RRC signaling, the UE may configure the RSTD for another TRP and the RSTD for the reference TRP to be reported together.

19 is a block diagram illustrating the configuration of a communication node according to an embodiment of the present invention.

The communication node described with reference to FIG. 19 may be a terminal or a base station performing a method according to embodiments of the present invention. Referring to FIG. 19 , 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 component 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).

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, and the like, 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)

An operating method of a first terminal for a synchronized operation according to time-sensitive networking,
Receiving information about a reference time (reference time) from the base station;
obtaining an offset of the first terminal with respect to the reference time or information from which the offset can be derived, and deriving the offset from information from which the offset can be derived;
determining a time point at which uplink transmission is performed by reflecting the offset in the reference time; and
Comprising the step of performing the uplink transmission at the determined time point,
How the terminal operates. The method according to claim 1,
The reference time is generated by a global reference clock of the base station and received from the base station, or is generated by a global reference clock of a second terminal other than the first terminal and transmits the base station from the second terminal. received through
How the terminal operates. 3. The method according to claim 2,
The reference time is commonly applied to a terminal group including the first terminal and the second terminal,
How the terminal operates. The method according to claim 1,
The offset is a method based on timing advance (TA), or a round-trip-time (RTT, round-trip time) or Rx-Tx time difference measured by the first terminal and Rx- obtained in a way based on the combination of Tx time difference,
How the terminal operates. 5. The method according to claim 4,
The TA is defined by a difference between a boundary of a downlink slot received by the first terminal and a boundary of an uplink slot transmitted by the first terminal having the same index as the downlink slot,
How the terminal operates. 5. The method according to claim 4,
The RTT is measured in the first terminal based on the downlink reference signal of the base station and the uplink reference signal of the first terminal, or is measured in the base station and transmitted from the base station to the first terminal,
How the terminal operates. 7. The method of claim 6,
The downlink reference signal is at least one of a downlink positioning reference signal (PRS), a synchronization signal (SS)/physical broadcast channel (PBCH) block, and a channel state information (CSI)-RS, and the uplink reference signal is At least one of a link PRS and a sounding reference signal (SRS),
How the terminal operates. 7. The method of claim 6,
When the RTT is measured in the first terminal, the RTT measurement using the downlink reference signal is triggered by downlink control information (DCI), and the DCI is the downlink reference signal. Further comprising information indicating the resource,
How the terminal operates. 9. The method of claim 8,
When the DCI allocates a downlink transport block (TB), a downlink physical data channel (PDSCH, physical downlink shared channel) to resource elements (RE) to which the downlink reference signal is not mapped. Whether or not rate matching that maps to is applied is further indicated by the DCI,
How the terminal operates. The method according to claim 1,
The offset of the first terminal or information capable of deriving the offset is DCI or terminal group-specific PDSCH included in a UE-specific downlink physical control channel (PDCCH). Received from the base station through an included MAC random access response (RAR) or MAC CE (control element), or measured in the first terminal and reported to the base station through a terminal-specific uplink channel,
How the terminal operates. 11. The method of claim 10,
When the offset is obtained in a manner based on timing advance (TA), the MAC RAR or the MAC CE includes a timing advance command (TAC) that is an initial value of TA or a value accumulated in a current TA doing,
How the terminal operates. 12. The method of claim 11,
The MAC RAR or the MAC CE includes information on a unit time applied to the TA and/or the TAC,
How the terminal operates. As an operating method of a base station for synchronized operation according to time-sensitive networking,
providing information on a reference time generated by a global reference clock to a first terminal;
obtaining an offset of the first terminal with respect to the reference time or information for deriving the offset and providing it to the first terminal; and
Comprising the step of performing uplink reception for the first terminal,
The first terminal performs uplink transmission corresponding to the uplink reception at a time point determined by reflecting the offset in the reference time,
How the base station works. 14. The method of claim 13,
The reference time is commonly applied to a terminal group including the first terminal and the second terminal,
How the base station works. 14. The method of claim 13,
The offset is a method based on timing advance (TA), or a round-trip-time (RTT, round-trip time) or Rx-Tx time difference measured by the first terminal and Rx- obtained in a way based on the combination of Tx time difference,
How the base station works. 16. The method of claim 15,
The RTT is measured by the base station based on the downlink reference signal of the base station and the uplink reference signal of the first terminal and transmitted from the base station to the first terminal,
How the base station works. 17. The method of claim 16,
The downlink reference signal is at least one of a downlink positioning reference signal (PRS), a synchronization signal (SS)/physical broadcast channel (PBCH) block, and a channel state information (CSI)-RS, and the uplink reference signal is At least one of a link PRS and a sounding reference signal (SRS),
How the base station works. 14. The method of claim 13,
The offset of the first terminal or information capable of deriving the offset is DCI or terminal group-specific PDSCH included in a UE-specific downlink physical control channel (PDCCH). provided to the first terminal through an included MAC random access response (RAR) or MAC CE (control element),
How the base station works. 19. The method of claim 18,
When the offset is obtained in a manner based on timing advance (TA), the MAC RAR or the MAC CE includes a timing advance command (TAC) that is an initial value of TA or a value accumulated in a current TA doing,
How the base station works. 19. The method of claim 18,
The MAC RAR or the MAC CE includes information on a unit time applied to the TA and/or the TAC,
How the base station works.

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