KR20220094162A - Measurement management method for moving cell, and apparatus therefor - Google Patents

Abstract

A measurement management method performed by a terminal in a non-terrestrial network includes the steps of: receiving configuration information about a measurement gap and SMTC window(s) included in the measurement gap from a satellite base station; determining a timing offset to be applied to the SMTC window(s) within the set measurement gap; and performing measurement within the measurement gap by applying the timing offset to the set SMTC window(s).

Description

Measurement management method for mobile cell communication and apparatus therefor

The present invention relates to a non-terrestrial network (NTN), and more particularly, a measurement reflecting a delay time that changes due to the mobility of a non-terrestrial node in a non-terrestrial network based on a 5G NR (new radio) system It relates to a management method and an apparatus therefor.

It is necessary to develop mobile satellite communication technology in preparation for communication disruption that may occur in cellular shadow areas such as mountainous areas, desert areas, island areas, and the sea, and in areas where the terrestrial network collapses due to various disasters such as earthquakes, tsunamis, and war. Since the satellite communication network is maintained even when the terrestrial network is disrupted due to a disaster or disaster, the disaster or disaster area is connected without being disconnected from the outside, making it possible to maintain individual survival and safety.

In addition, the need for mobile satellite communication technology is increasing for the establishment of a hyper-connected society that provides mobile communication services even in areas where communication was not possible in the past, such as in mountains and remote areas where there is no communication infrastructure. In the 3rd generation partnership project (3GPP), based on 5G new radio (NR) technology, a non-terrestrial base station (eg, a base station using an airborne platform such as a satellite base station or an airship) Standardization of a non-terrestrial network (NTN) used is in progress On the other hand, in a non-terrestrial network, there is a problem in that a delay between a terminal and a base station increases as the size of a cell increases and a communication distance increases. Such a large delay is the length of a random access preamble, a timing advance value, and a random access response (RAR) in initial access performed by the terminal to the base station. ) affects the size of the window, which can also affect the performance of the entire system.

In addition, various transmission delays according to the altitude of the satellite and changes in transmission delay due to the mobility of the terminal and the satellite may occur. According to the existing standard, the measurement gap is set to be UE-specific, and the SSB-based RRM measurement timing configuration (SMTC) window(s) in the measurement gap is for each terminal or FR1 (frequency range 1) It can be set for each /FR2 (frequency range 2). For example, the measurement gap may be set to a duration and a period including the SMTC window(s) to be measured. In NTN, it is difficult to measure adjacent cells of intra/inter frequency with a fixed measurement gap setting and SMTC setting as in the existing standard.

It is an object of the present invention to solve the above problems, to provide a method for managing a measurement of a terminal that can efficiently reflect a delay time varying according to the mobility of a satellite base station in a non-terrestrial network in a measurement.

Another object of the present invention to solve the above problems is to provide a configuration of a terminal that performs a measurement management method that can efficiently reflect a delay time that varies according to the mobility of a satellite base station in a non-terrestrial network to a measurement. have.

An embodiment of the present invention for achieving the above object is a measurement management method performed by a terminal in NTN, and configuration information for a measurement gap from a satellite base station and SMTC window(s) included in the measurement gap receiving; transmitting the location information of the terminal to the satellite base station; Receiving a message including information on a timing offset determined based on the location information of the terminal from the satellite base station; and performing measurement by applying the timing offset to the measurement gap and/or the SMTC window(s) set through the configuration information.

The timing offset may be determined in consideration of location information of the terminal, location information of the satellite base station, and a feeder link delay for the satellite base station.

The timing offset has a positive value or a negative value according to the elevation angle of the satellite base station with respect to the terminal, and the measurement start time is obtained by applying the timing offset to the start time of the set SMTC window(s). can be decided.

When the timing offset has a positive value, the measurement start time may be later than the set measurement gap or the start time of the SMTC window(s) by the absolute value of the timing offset.

When the timing offset has a negative value, the measurement start time may be earlier than the set measurement gap or the start time of the SMTC window(s) by the absolute value of the timing offset.

The measurement management method adds, when the timing offset is applied to the SMTC window(s), reporting information on the SMTC window(s) that are not measured within the set measurement gap due to the timing offset to the base station. can be included as

The message including the information on the timing offset may further include information indicating whether the timing offset is applied only to the set measurement gap or whether the timing offset is also applied to the set SMTC window(s).

Another embodiment of the present invention for achieving the above object is a measurement management method performed by a terminal in NTN, and configuration information for a measurement gap from a satellite base station and SMTC window(s) included in the measurement gap receiving; determining a timing offset to be applied to the SMTC window(s) within the set measurement gap; and performing measurement within the measurement gap by applying the timing offset to the set SMTC window(s).

The timing offset may be calculated based on the location information of the terminal and the location information of the satellite base station.

The timing offset has a positive value or a negative value according to the elevation angle of the satellite base station with respect to the terminal, and the measurement start time is obtained by applying the timing offset to the start time of the set SMTC window(s). can be decided.

When the timing offset has a positive value, the measurement start time may be later than the start time of the set SMTC window(s) by the absolute value of the timing offset.

When the timing offset has a negative value, the measurement start time may be the later of the set measurement gap start time and the set SMTC window(s) start time.

In the measurement management method, when the actual measurement interval according to the measurement start time deviates from the set measurement gap, transmitting a first message for reporting the fact that the actual measurement interval deviates from the set measurement gap to the base station may additionally include.

The first message is a cell identifier (cell ID) of the satellite base station or a synchronization signal block (SSB) identifier of the satellite base station, the timing offset, and/or the delay time between the terminal and the satellite base station calculated by the terminal. may include information about

An embodiment of the present invention for achieving the above other object, as a terminal operating in NTN, a processor; a memory in electronic communication with the processor; and instructions stored in the memory, wherein, when executed by the processor, the instructions enable the terminal to: Receive configuration information for a measurement gap and SMTC window(s) included in the measurement gap from a satellite base station to do; determining a timing offset to be applied to the SMTC window(s) within the set measurement gap; and performing the measurement within the measurement gap by applying the timing offset to the set SMTC window(s).

The timing offset may be calculated based on the location information of the terminal and the location information of the satellite base station.

The timing offset has a positive value or a negative value according to the elevation angle of the satellite base station with respect to the terminal, and the measurement start time is obtained by applying the timing offset to the start time of the set SMTC window(s). can be decided.

When the timing offset has a positive value, the measurement start time may be later than the start time of the set SMTC window(s) by the absolute value of the timing offset.

When the timing offset has a negative value, the measurement start time may be the later of the set measurement gap start time and the set SMTC window(s) start time.

When the actual measurement interval according to the measurement start time deviates from the set measurement gap, the commands transmit a first message for the terminal to report the fact that the actual measurement interval is out of the set measurement gap to the satellite base station can be performed additionally.

According to embodiments of the present invention, it is possible to reflect a timing offset according to a large variable delay time in the NTN measurement, and to efficiently update and manage the timing offset. Accordingly, it is possible to reduce the signaling overhead between the satellite base station and the terminal and increase the accuracy of the measurement result. Through this, the effect of improving the performance of the overall system can be obtained.

1A and 1B are conceptual diagrams illustrating a communication environment to which embodiments of the present invention are applied.
2 is a conceptual diagram for explaining the concepts of a common delay time and a differential delay time according to a location of a terminal in long-distance communication.
3 is a conceptual diagram for explaining a concept in which a common delay time is defined for a specific beam.
4 is a conceptual diagram for explaining various common delays existing in a non-terrestrial network environment.
5 is a flowchart illustrating a measurement management method according to an embodiment of the present invention.
6 is a flowchart illustrating a measurement management method according to another embodiment of the present invention.
7 is a conceptual diagram for explaining cases in which a measurement gap/SMTC window(s) set by a base station and a timing offset according to embodiments of the present invention are applied.
8 is a block diagram illustrating an embodiment of a communication node according to 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 an element is referred to as being “connected” or “connected” to another element, it is understood that it may be directly connected or connected to the other element, but other elements may exist in between. it should be On the other hand, when it is said that a certain element is "directly connected" or "directly connected" to another element, it should be understood that the other element does not exist in the middle.

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

Unless defined otherwise, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in 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

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. Here, a wireless communication network may be used in the same meaning as a wireless communication system.

Hereinafter, for convenience of description, the term 'satellite base station' is used as a term representing a non-terrestrial base station or a mobile base station. However, the methods and apparatuses described below may be applied not only to a satellite base station but also to a base station using an airborne platform - such as an airship.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

1A and 1B are conceptual diagrams illustrating a communication environment to which embodiments of the present invention are applied.

Referring to FIG. 1A, in a non-terrestrial network environment in which standardization is in progress in 3GPP, the base stations gNB, 112, 113, and 123 are on the ground while the satellites 111, 121, and 122 perform the role of a relay. can That is, in this case, the satellite base station operates as a transparent node defined in 3GPP NTN. Referring to FIG. 1B , central units (CUs) 133 and 142 of the base station may be located on the ground, and distributed units (DUs) of the base station may be located on satellites 131 , 132 and 141 . Alternatively, the base station (gNB) itself may be located in the satellite. That is, in this case, the satellite base station operates as a regenerative node defined in 3GPP NTN. In the following description, a 'satellite base station' is a term that encompasses a node operating as the transparent node or a regenerative node.

One or more NR cells may be defined through one satellite. In addition, one gNB may provide services via more than one satellite. A satellite may be classified as a low earth orbit (LEO) satellite, a medium earth orbit (MEO) satellite, or a geostationary equatorial orbit (GEO) satellite.

In this case, as the cell radius and the height of the base station (eg, the satellite base station) increase, a large difference may occur in signal transmission times according to the locations of the terminals.

2 is a conceptual diagram for explaining the concept of a common delay time and a differential delay time according to a location of a terminal in long-distance communication.

Referring to FIG. 2 , a delay time (ie, common delay time) according to a distance 211 between the terminal 210 and the satellite base station 201 positioned below the vertical direction within the area of the satellite base station 201 . And, delay times (ie, common delay time+differential delay) according to the distance 221 between the terminal 220 and the satellite base station 201 located at various points are shown.

That is, the delay time of the terminal 210 and the delay time of the terminal 220 may have a difference by the differential delay time. In this case, the arrival time of the signal transmitted from the terminal 210 at the satellite base station 201 and the arrival time of the signal transmitted from the terminal 220 at the satellite base station 201 have a difference by the differential delay time. .

That is, the common delay time is the unidirectional delay time of the shortest distance, the average distance, or the longest distance at a specific point in time between the base station and the terminal within the corresponding area, or a specific value defined by the base station (or system) (eg, satellite height) can be

3 is a conceptual diagram for explaining a concept in which a common delay time is defined for a specific beam.

Referring to FIG. 3 , the common delay time is a delay time at the center of a beam of a base station (a point where the elevation angle of the beam is 0 degrees or a point where the gain of the beam is greatest) at a specific point in time in relation to the beam or the corresponding It may also be defined as a delay time for a point having the largest signal to noise ratio (SNR) in the region.

4 is a conceptual diagram for explaining various common delays existing in a non-terrestrial network environment.

Referring to FIG. 4 , at least three types of radio links may exist in a non-terrestrial network environment. At least three types of radio links are a service link 431 between the terminal 410 and the satellite base station 421 , an inter-satellite link (ISL) 441 , and a terrestrial connection to the data network 470 . It may include a feeder link (451, 452) between the gateway 460 and the satellite base stations (421, 422).

In this case, the common delay time ( _DS ) of the service link, the common delay time ( _DI ) of the inter-satellite link, and the common delay time ( _DF ) of the feeder link may exist, and the common delay described in FIGS. 2 and 3 . is mainly corresponding to the common delay ( _DS ) of the service link.

When the terminal knows the type of satellite (eg, LEO, MEO, or GEO) and the orbit of the satellite, it can infer an elevation angle with the satellite and the distance from the satellite. Since the type of satellite and the orbit of the satellite greatly affect the signal delay and signal strength between the terminal and the satellite base station, it is important for the terminal to know the type and orbit of the satellite for initial access, handover, paging ( It is helpful in various control procedures such as paging).

As described above, the types of satellites can be largely classified into geostationary orbiting satellites (GEO) and non-geostationary orbiting satellites (MEO/LEO). Compared to a geostationary orbit satellite whose service area does not change over time, a non-geostationary orbit satellite has a characteristic that the service area changes over time. The service area that is changed due to the mobility of the non-geostationary orbit satellite is divided into two types, an earth fixed beam and a moving beam. In the case of the terrestrial fixed beam, even if the satellite moves, the terrestrial cell is not changed, and in the mobile beam, the cell information is changed together with the moving satellite.

The satellite communication delay may vary depending on the position of the satellite, the position of the ground station, and the position of the terminal. First, delay variation may occur according to satellite mobility in a terminal in a fixed location. In the case of GEO, a maximum of 16 ms is expected, and in the case of LEO serving at 1200 km, a maximum of 6.44 ms is expected. A delay difference may occur depending on the location of the terminal in the beam serviced by the satellite at the same time. The value may have a large difference depending on the size of the beam. Finally, the distance between the satellite and the ground station may vary depending on the time of the ground station connected to the satellite, and if the LOS environment is not supported, the ground station may be connected to the ground station through connection with other satellites. These connections may change according to satellite deployment. In summary, in the case of the transparent mode, the satellite communication delay is defined as the delay considering the location between the terminal and the satellite, and in the case of the regenerative mode, it is defined as the delay considering the location between the satellite and the ground station as well as the delay considering the location between the terminal and the satellite. should be

As described above, since various transmission delays according to the altitude of the satellite and changes in transmission delay due to the mobility of the terminal and the satellite occur, a fixed measurement gap setting and SMTC (synchronization signal block (SSB) )-based RRM measurement timing configuration), it is difficult to measure adjacent cells of intra/inter frequency.

According to the existing standard, the measurement gap may be set UE-specifically, and the SMTC window may be set per UE or per frequency range 1 (FR1)/frequency range 2 (FR2). For example, the measurement gap may be set to a duration and a period including the SMTC window(s) to be measured. Specifically, the start subframe of the measurement gap may be determined by Equation 1 below.

However, unlike the existing terrestrial cellular communication, in NTN, due to the fast mobility of the satellite, when the preset measurement gap and SMTC information are used, as the delay time between the terminal and the adjacent cells changes, the terminal performs measurement on the adjacent cells. There may be problems that cannot be performed. Alternatively, when the altitudes of the satellites or vehicles are different from each other, since the delay times for the satellites or the vehicles have a large difference according to the arranged altitudes, it may be difficult to measure them all in one measurement gap. In particular, since transmission (reception) to/from the serving cell of the UE is stopped during the measurement gap, a method for efficiently setting the measurement gap in consideration of the above matters should be provided. Hereinafter, embodiments of a measurement gap operation method for NTN are described.

Setting up multiple measurement gaps

According to the altitude of the satellite, the delay time between the terminal and the satellite, or the type of the satellite (geostationary orbit satellite, low orbit satellite), the base station may set two or more measurement gaps for the terminal. For example, two or more measurement gaps are the measurement gap for cell/beam/BWP formed by geostationary orbiting satellites with little delay time change and the measurement gap for cell/beam/BWP formed by low orbiting satellites having similar delay times may include

To this end, the base station and the terminal may define MeasGapConfig in the form of a list, and assign a MeasGapConfig Id to each configuration. For example, in an implicit way, the ID for the first MeasGapConfig defined in the list may be defined as (MeasGapConfig Id = 0) and IDs may be assigned in the order included in the list. MeasGapConfig Id may be defined for each MeasGapConfig in the list in an explicit way.

In this case, measId may be mapped to and set to MeasGapConfig Id. Table 1 below shows examples of MeasIdToAddMod information elements according to an embodiment of the present invention.

MeasIdToAddMod
{
measId ::= INTEGER (1..maxMeasId[32])
measObjectId ::= INTEGER (1..maxObjectId[32])
reportConfigId ::= INTEGER (1..maxReportConfigId[32])
measGapConfigId ::= INTEGER (1..maxGapId[])
}

The terminal may optionally include a function to support multi-measurement gap configuration. When the terminal transmits information on the UE capability to the base station, it may include whether a multi-measurement gap setting function is supported. When it is confirmed that the terminal supports the multi-measurement gap setting function, the base station may configure the multi-measurement gap for the terminal.

Measurement gap setting using the location information of the terminal

The terminal in the measurement report (measurement report) its own location information (eg, GPS reception function, A-GNSS (Assisted Global Navigation Satellite System), or OTDOA (Observed Time Differential Of Arrival) location information measured by the location information, or Including Enhanced Cell ID (E-CID), it may be transmitted periodically or aperiodically (eg, when a specific condition is satisfied) to the base station. The base station identifies adjacent cells or beam/BWP to be measured using location information of the terminal, ephemeris information of satellites, and synchronization signal block (SSB) period information, and measurement object information (SMTC period, etc.) After determining, the measurement gap configuration in which the determined measurement object information is reflected may be transmitted to the terminal through the RRCReconfiguration message.

In order to reflect the delay time variation due to the mobility of the satellite, the base station periodically or aperiodically receives the location information report of the terminal, and uses the location information and feeder link delay of the satellites related to the terminal's neighboring cells. Thus, a new measurement gap and SMTC can be set. However, this method may have a disadvantage of increasing signaling overhead due to frequent change of measurement settings according to the mobility of the satellite and the terminal.

Alternatively, the base station determines a timing offset (positive or negative value) for reflecting the delay time variation due to mobility for a previously set measurement gap, and transmits the determined timing offset to the terminal through a dedicated channel/dedicated message can be set to For example, a new parameter (eg, Gap Timing offset) may be defined in the GapConfig information element (IE) of the RRCReconfiguration message. Alternatively, a MAC control element (CE) including the timing offset (eg, gap timing offset) may be defined. For example, the base station may determine a new timing offset applied to a preset measurement gap using the location information of the terminal, the location information of the satellite, and the feeder link delay. Upon receiving the new timing offset, the UE may pull or delay the start time of the next measurement gap by the timing offset. In this case, if the GapConfig (eg, gapoffset, measurement gap length, measurement gap period, etc.) set by RRCReconfiguration is not reset, the measurement gap may be determined by reflecting the new timing offset in the existing values. Through this, the terminal and the base station can manage the same measurement gap timing.

The UE may optionally include a function of supporting a timing offset for setting a dynamic measurement gap. When the terminal transmits information on the UE capability to the base station, it may include whether a function supporting a timing offset for dynamic measurement gap configuration is supported. When it is confirmed that the terminal supports the function of supporting the timing offset for setting the dynamic measurement gap, the base station may periodically receive the location information of the terminal from the terminal and provide a timing offset for the measurement gap.

Meanwhile, the same timing offset may be applied to the SMTC window included in the measurement gap. That is, like the measurement gap setting, the timing offset may also be reflected in the SMTC window setting set by the base station. The terminal and the base station can know the orbit information of the satellite through SIB2/3 and the satellite ephemeris information. Since the movement speed of the satellite base station is much faster than the movement speed of the terminal, the number of cells that the terminal can move from the currently serving cell can be compressed into one or two. That is, since the next cell in the current service area may be specified, the value of the timing offset applied to the measurement gap may be equally applied to the SMTC window. To support this, the base station transmits information on the timing offset and a parameter (boolean value) indicating whether the timing offset can be equally applied to the SMTC window belonging to the measurement gap to the terminal using RRC or MAC CE. can Meanwhile, an SMTC window that cannot be received within the measurement gap may be generated due to the influence of the timing offset. In this case, the terminal can provide the base station with information on the unreceived SMTC window by delivering measId or measObjectId corresponding to the unreceived SMTC window to the base station using a dedicated message.

5 is a flowchart illustrating a measurement management method according to an embodiment of the present invention.

Referring to FIG. 5 , the terminal 510 may receive a measurement gap and configuration information on the SMTC window(s) included in the measurement gap from the satellite base station 520 ( S510 ). In this case, the configuration information for the measurement gap and the SMTC window(s) included in the measurement gap may be configured by the GapConfig IE of the RRCReconfiguration message described above.

Next, the terminal 510 may periodically or aperiodically report its location information to the base station 520 ( S520 ). Next, the satellite base station 520 may transmit a message including information on the timing offset determined based on the location information of the terminal to the terminal, and the terminal 510 may receive a message including information on the timing offset. There is (S530). In this case, the timing offset may be determined in consideration of the location information of the terminal, location information of the satellite base station, and feeder link delay for the satellite base station as described above. In addition, the message including information on the timing offset may further include information indicating whether the timing offset is applied only to the set measurement gap or whether the timing offset is also applied to the set SMTC window(s). .

Finally, the UE may perform measurement by applying the timing offset to the measurement gap and/or the SMTC window(s) set through the configuration information (S540).

On the other hand, the timing offset has a positive value or a negative value according to the elevation angle of the satellite base station with respect to the terminal, and the measurement starts by applying the timing offset to the start time of the set SMTC window(s) The timing may be determined. For example, when the timing offset has a positive value, the measurement start time may be determined to be later than the set measurement gap or the start time of the SMTC window(s) by the absolute value of the timing offset. Meanwhile, when the timing offset has a negative value, the measurement start time may be determined to be earlier than the set measurement gap or the start time of the SMTC window(s) by the absolute value of the timing offset.

Meanwhile, in the measurement management method, when the timing offset is applied to the SMTC window(s), the terminal transmits information on the SMTC window(s) that are not measured within the set measurement gap due to the timing offset to the base station A step of reporting (S550) may be additionally performed.

Update measurement gap settings using SMTC timing offset

Several measurement objects may exist in the measurement gap, and these measurement objects must be set to be efficiently included in the measurement gap. As described above, even when the base station applies the timing offset to the measurement gap or does not apply the timing offset, the terminal applies the self-determined SMTC timing offset to the SMTC window(s) within the set measurement gap and uses location information Thus, by updating the SMTC timing offset, it is possible to correct the amount of change in delay time due to the mobility of the satellite. Through this, signaling overhead for resetting the measurement gap and the SMTC window can be reduced.

Hereinafter, a procedure for a method of updating the measurement gap setting using the SMTC timing offset will be described.

The base station may provide configuration information of the measurement gap and the SMTC window to the terminal through RRCReconfiguration.

A function supporting the SMTC timing offset may be provided as an option in the terminal and the base station. If the terminal supports the function to support the SMTC timing offset, the terminal may inform the base station of whether the SMTC timing offset is supported through an RRC message (eg, UE capability). The base station may set whether to use the SMTC timing offset support function for the terminal as true or false through an RRC message (eg, MeasConfig).

The UE supporting the SMTC timing offset may determine the actual start time of the SMTC window(s) within the set measurement gap as an offset (ie, the SMTC timing offset) in subframes, slots, or symbols. As an example of a method of determining the SMTC timing offset, the terminal receives the cell ID (cell ID) provided as a measurement object by the base station, ephemeris information of the satellite serving the cell corresponding to the cell ID (received through the SIB of the serving cell) or ephemeris information stored in the terminal), the SMTC timing offset may be calculated using the location information of the terminal.

Since the SMTC timing offset depends on an elevation angle between the UE and the satellite, it may have a positive value or a negative value. For example, when the SMTC timing offset has a positive value, the UE may receive the SSB of the neighboring cell/beam/BWP at a time later than the set SMTC reception start timing by the SMTC timing offset. In this case, the UE may finish the measurement at the earlier of the SMTC duration (end time) and the end time of the measurement gap. If a tuning offset for RF tuning before and after measurement is set within the measurement gap, the terminal is earlier by the tuning offset from the earlier of the SMTC duration (end time) and the end time of the measurement gap The measurement should be terminated at When the SMTC timing offset has a negative value, the UE may start the measurement at the later of the configured SMTC reception start timing and the start time of the measurement gap. If the tuning offset for RF tuning before and after the measurement is set within the measurement gap, the UE starts the measurement after a time delayed by the tuning offset from the later of the set SMTC reception start timing and the start time of the measurement gap shall. That is, the UE may perform measurement only within the measurement gap, and may apply an offset reflecting the changing delay time to match the measurement object reception timing.

If the SMTC timing offset is changed as the position of the satellite and the position of the terminal change, the number of measurement objects (measurement objects (SSB/CSI-RS, etc.)) that the terminal can receive within the measurement window may be reduced. , and thus the accuracy of the measurement may be lowered. The base station may request the terminal to report this to the base station when the SMTC window set by the base station is out of the measurement gap due to the SMTC timing offset. For example, a corresponding field indicating the request may be added to a measurement report config.

Due to the SMTC timing offset applied by the UE, when the SMTC window (ie, the SMTC window for actually performing measurement; 'real measurement window' in a drawing to be described later) is out of the measurement gap set by the base station, it is an RRC message or MAC The CE may be used to report to the base station through a dedicated channel. For example, when using an RRC measurement report message, information such as a cell ID (or SSB ID), an applied SMTC timing offset, and/or a delay time between the terminal and the base station calculated by the terminal is included in the message and reported to the base station can be If necessary, the base station receiving the message determines a new measurement gap and SMTC window(s) for the terminal by using the above-described method or information provided by the terminal, and may transmit a reset message to the terminal. Until receiving the corresponding message from the base station, the terminal may perform measurement using the existing configuration and the SMTC timing offset, and may transmit the report message according to a reporting condition. Upon receiving the reset message from the base station, the terminal may apply the measurement gap setting included in the reset message to the next measurement gap, and apply the reset SMTC timing offset.

6 is a flowchart illustrating a measurement management method according to another embodiment of the present invention.

Referring to FIG. 6 , the terminal 510 may receive a measurement gap and configuration information on the SMTC window(s) included in the measurement gap from the satellite base station 520 ( S610 ). In this case, the configuration information for the measurement gap and the SMTC window(s) included in the measurement gap may be configured by the GapConfig IE of the RRCReconfiguration message described above.

Next, the terminal 510 may determine a timing offset to be applied to the SMTC window(s) within the set measurement gap (S620). As described above, the timing offset may be calculated based on the location information of the terminal and the location information of the satellite base station.

Finally, the terminal 510 may perform measurement within the measurement gap by applying the timing offset to the set SMTC window(s) (S630).

The timing offset has a positive value or a negative value according to the elevation angle of the satellite base station with respect to the terminal, and the measurement start time is obtained by applying the timing offset to the start time of the set SMTC window(s). can be decided. For example, when the timing offset has a positive value, the measurement start time may be determined to be later than the start time of the set SMTC window(s) by the absolute value of the timing offset. Meanwhile, when the timing offset has a negative value, the measurement start time may be determined to be the later of the set measurement gap start time and the set SMTC window(s) start time.

On the other hand, when the actual measurement period ('real measurement window' in a drawing to be described later) according to the measurement start time is out of the set measurement gap, the terminal reports the fact that the measurement start time is out of the set measurement gap to the base station message can be transmitted (S640).

7 is a conceptual diagram for explaining cases in which a measurement gap/SMTC window(s) set by a base station and a timing offset according to embodiments of the present invention are applied.

7 (a) shows the configuration of the measurement gap set by the satellite base station and the SMTC window(s) included in the measurement gap. That is, in step S510 of FIG. 5 and step S610 of FIG. 6 , a measurement gap configured to the terminal according to the configuration information received from the satellite base station and the SMTC window(s) included in the measurement gap are shown. Meanwhile, an RF tuning offset for RF tuning may be set before and after the SMTC window(s) within the measurement gap.

7 (b) shows a configuration in which only the SMTC timing offset (smtc Offset) is applied to the SMTC window(s) within the set measurement gap, and in FIG. 7 (c), the measurement gap timing offset for the set measurement gap A configuration in which (MG Offset) is applied and an SMTC timing offset (smtc Offset) is applied to the SMTC window(s) in the measurement gap is shown.

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

The communication node illustrated in FIG. 8 may be a terminal or a satellite base station according to embodiments of the present invention. Referring to FIG. 8 , the communication node 800 may include at least one processor 810 , a memory 820 , and a transceiver 830 connected to a network to perform communication. In addition, the communication node 800 may further include an input interface device 840 , an output interface device 850 , a storage device 860 , and the like. Each of the components included in the communication node 800 may be connected by a bus 870 to communicate with each other.

The processor 810 may execute a program command stored in at least one of the memory 820 and the storage device 860 . The processor 810 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 820 and the storage device 860 may be configured as at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory 820 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, etc. alone or in combination. The program instructions recorded on the computer-readable medium may be specially designed and configured for the present invention, or may be known and available to those skilled in the art of computer software.

Examples of computer-readable media may include hardware devices specially configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions may 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.

In addition, the above-described method or apparatus may be implemented by combining all or part of its configuration or function, or may be implemented separately.

Although the above has been described with reference to preferred embodiments of the present invention, those skilled in the art can variously modify and change the present invention within the scope without departing from the spirit and scope of the present invention as set forth in the claims below. You will understand that it can be done.

Claims (20)

As a measurement management method performed by a terminal in a non-terrestrial network,
Receiving a measurement gap (gap) and configuration information for the SMTC window (s) included in the measurement gap from the satellite base station;
transmitting the location information of the terminal to the satellite base station;
receiving a message including information on a timing offset determined based on the location information of the terminal from the satellite base station; and
Comprising performing measurement by applying the timing offset to the measurement gap and/or the SMTC window(s) set through the configuration information,
How to manage your measurements. The method according to claim 1,
The timing offset is determined in consideration of location information of the terminal, location information of the satellite base station, and a feeder link delay for the satellite base station,
How to manage your measurements. The method according to claim 1,
The timing offset has a positive value or a negative value depending on the elevation angle of the satellite base station with respect to the terminal, and the measurement start time is obtained by applying the timing offset to the start time of the set SMTC window(s). determined,
How to manage your measurements. 4. The method according to claim 3,
When the timing offset has a positive value, the measurement start time is a time later than the set measurement gap or the start time of the SMTC window(s) by the absolute value of the timing offset,
How to manage your measurements. 4. The method according to claim 3,
When the timing offset has a negative value, the measurement start time is a time earlier than the start time of the set measurement gap or SMTC window(s) by the absolute value of the timing offset,
How to manage your measurements. The method according to claim 1,
When the timing offset is applied to the SMTC window(s), further comprising the step of reporting information on the SMTC window(s) that are not measured within the set measurement gap due to the timing offset to the base station,
How to manage your measurements. The method according to claim 1,
The message including the information on the timing offset further includes information indicating whether the timing offset is applied only to the set measurement gap or whether the timing offset is also applied to the set SMTC window(s).
How to manage your measurements. As a measurement management method performed by a terminal in a non-terrestrial network,
Receiving a measurement gap (gap) and configuration information for the SMTC window (s) included in the measurement gap from the satellite base station;
determining a timing offset to be applied to the SMTC window(s) within the set measurement gap; and
Comprising performing measurement within the measurement gap by applying the timing offset to the set SMTC window(s),
How to manage your measurements. 12. The method of claim 11,
The timing offset is calculated based on the location information of the terminal and the location information of the satellite base station,
How to manage your measurements. 9. The method of claim 8,
The timing offset has a positive value or a negative value depending on the elevation angle of the satellite base station with respect to the terminal, and the measurement start time is obtained by applying the timing offset to the start time of the set SMTC window(s). determined,
How to manage your measurements. 11. The method of claim 10,
When the timing offset has a positive value, the measurement start time is a time later than the start time of the set SMTC window(s) by the absolute value of the timing offset,
How to manage your measurements. 11. The method of claim 10,
When the timing offset has a negative value, the measurement start time is the later of the start time of the set measurement gap and the start time of the set SMTC window(s),
How to manage your measurements. 11. The method of claim 10,
When the actual measurement period according to the measurement start time is out of the set measurement gap, further comprising the step of transmitting a first message reporting the fact that the actual measurement period is out of the set measurement gap to the base station,
How to manage your measurements. 14. The method of claim 13,
The first message is a cell identifier (cell ID) of the satellite base station or a synchronization signal block (SSB) identifier of the satellite base station, the timing offset, and/or the delay time between the terminal and the satellite base station calculated by the terminal. containing information about
How to manage your measurements. As a terminal operating in a non-terrestrial network,
processor;
a memory in electronic communication with the processor; and
including instructions stored in the memory;
When executed by the processor, the instructions cause the terminal to:
Receiving a measurement gap (gap) and configuration information for the SMTC window (s) included in the measurement gap from the satellite base station;
determining a timing offset to be applied to the SMTC window(s) within the set measurement gap; and
To perform the step of performing the measurement within the measurement gap by applying the timing offset to the set SMTC window(s),
terminal. 16. The method of claim 15,
The timing offset is calculated based on the location information of the terminal and the location information of the satellite base station,
terminal. 16. The method of claim 15,
The timing offset has a positive value or a negative value depending on the elevation angle of the satellite base station with respect to the terminal, and the measurement start time is obtained by applying the timing offset to the start time of the set SMTC window(s). determined,
terminal. 18. The method of claim 17,
When the timing offset has a positive value, the measurement start time is a time later than the start time of the set SMTC window(s) by the absolute value of the timing offset,
terminal. 18. The method of claim 17,
When the timing offset has a negative value, the measurement start time is the later of the start time of the set measurement gap and the start time of the set SMTC window(s),
terminal. 11. The method of claim 10,
When the actual measurement interval according to the measurement start time deviates from the set measurement gap, the commands transmit, by the terminal, a first message for reporting the fact that the actual measurement interval deviates from the set measurement gap to the satellite base station to additionally perform
terminal.

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