Satellite signal propagation delay variation compensation

Abstract

SOLUTION: A method for detecting satellite signal propagation delay variation includes: transmitting ephemeris data of a satellite and cell measurement window specifications to a terminal; receiving an indication from the terminal that a cell measurement signal will arrive at the terminal outside of a time frame defined by the cell measurement window specifications; modifying the cell measurement window specifications based on a difference in propagation delay between a serving cell, which defines the cell measurement window specifications, and a neighboring cell, which transmits the cell measurement signal, so that the cell measurement signal will arrive at the terminal within the time frame defined by the cell measurement window specifications, the satellite providing communication with the terminal for at least one of the serving cell and the neighboring cell; and transmitting modified cell measurement window specifications to the terminal.EFFECT: Satellite signal propagation delay variation can be compensated.SELECTED DRAWING: Figure 2A

Description

Background Art

[0001] While a terminal is connected to a serving cell of a network, a window of time during which the terminal can perform measurements on neighboring cell measurement signals is provided to the terminal. Some neighboring cells may utilize satellites for communication.

[0002] Due to the movement of the satellite, the propagation delay of the signal including the measurement signal sent to the terminal constantly changes. Such a delay can also change over time with the movement of the satellite for a given terminal. Due to this movement, the measurement signal timing also drifts.

[0003] If the terminal cannot perform measurements on neighboring cells, the terminal cannot report neighboring cell measurement results or cannot perform handover condition evaluation, which may affect handover performance.

Brief Description of the Drawings

[0004] FIG. 1A and FIG. 1B are schematic diagrams of a system for compensating for satellite signal propagation delay variations according to at least one embodiment of the present invention.

[0005] FIG. 2A and FIG. 2B are diagrams showing the relative timing between a measurement window and a measurement signal according to at least one embodiment of the present invention.

[0006] FIG. 3 is an operation flow for detecting satellite signal propagation delay variations according to at least one embodiment of the present invention.

[0007] FIG. 4 is an operation flow for reporting satellite signal propagation delay variations according to at least one embodiment of the present invention.

[0008] FIG. 5 is an operation flow for compensating for satellite signal propagation delay variations according to at least one embodiment of the present invention.

[0009] Figure 6 shows the relative timing between a measurement window and a measurement signal with a modified duration according to at least one embodiment of the present invention.

[0010] Figure 7 shows the relative timing between the measurement window and the measurement signal with a modified offset according to at least one embodiment of the present invention.

[0011] Figure 8 shows the relative timing between a measurement window with modified periodicity and a measurement signal according to at least one embodiment of the present invention.

[0012] Figure 9 shows the initial measurement window, additional measurement windows, and relative timing between measurement signals as defined in at least one embodiment of the present invention.

[0013] Figure 10 shows an operation flow for further compensating for satellite signal propagation delay variations according to at least one embodiment of the present invention.

[0014] Figure 11 shows a further operational flow for compensating for satellite signal propagation delay variations according to at least one embodiment of the present invention.

[0015] Figure 12 is a block diagram of an exemplary hardware configuration of a serving cell for satellite signal propagation delay variation compensation according to at least one embodiment of the present invention.

[0016] Figure 13 is a block diagram of an exemplary hardware configuration of a terminal for satellite signal propagation delay variation compensation according to at least one embodiment of the present invention.

[0017] Figures 14 to 30 are from U.S. Provisional Patent Application No. 63 / 140,578, for which this application claims priority. [Modes for carrying out the invention]

[0018] The following disclosure provides many different embodiments or examples for implementing different features of the subject matter provided. Specific examples of components, values, operations, materials, arrangements, etc., are set forth below for the sake of simplicity in this disclosure. These are, of course, merely examples and are not intended to be limiting. Other components, values, operations, materials, arrangements, etc., are also possible. In addition, this disclosure may repeat reference numbers and / or letters in various examples. This repetition is for the purpose of simplicity and clarity and does not, in itself, define the relationships between the various embodiments and / or configurations discussed.

[0019] During a terminal handover from a serving cell to a neighboring cell, the terminal can perform measurements to properly synchronize and connect to the neighboring cell. In some embodiments, such as when the serving cell and neighboring cell operate on different carrier frequencies, the terminal cannot communicate with the serving cell and synchronize and connect to the neighboring cell simultaneously. Therefore, in some radio technologies, such as 5G NR, the network provides a measurement gap that allows the terminal to perform appropriate measurements with the neighboring cell in order to synchronize and connect to it. In some embodiments, such as 5G NR, the terminal performs measurements on the neighboring cell's Synchronization Signal Block (SSB) during the measurement gap. In some embodiments, the network provides the timing of the neighboring cell SSB using an SSB-based Radio Resource Management (RRM) Measurement Time Configuration (SMTC) protocol.

[0020] While the terminal is connected to the serving cell, the network provides the terminal with an SMTC specification that defines a window of time during which the terminal can perform measurements on the neighboring cell SSB. The SMTC specification includes the periodicity, offset, and duration of the window and is based on the timing of the serving cell (also referred to as the primary cell (PCell)). The SMTC window periodicity (also referred to as the Measurement Gap Repetition Period (MGRP)) is, for example, 5, 10, 20, 40, 80, or 160 ms, and the SMTC window duration is, for example, 1, 2, 3, 4, or 5 ms. The serving cell does not schedule communication with the terminal during the measurement gap. The network ensures that SSBs from the neighboring cell are sent during the measurement gap so that the terminal can measure the intensity and quality of the neighboring cell SSB. In some embodiments, the terminal generates neighboring cell measurement results at standardized intervals.

[0021] In a Low Earth Orbit (LEO) Non-Terrestrial Network (NTN) scenario, the propagation delay of the nearest satellite cell SSB to the terminal constantly changes due to the movement of the satellite cell. The delay differs based on the relative position of the terminal on the ground. The nearest satellite cell delay also changes over time for the terminal as the satellite cell moves. Due to this movement, the nearest satellite cell SSB timing measured by the terminal also drifts. Although the terminal also moves, the effect of the terminal's movement on the ground is negligible compared to the satellite's speed.

[0022] In the NTN scenario, the terminal encounters different propagation delays between the serving satellite cell and the neighboring satellite cell. In some situations, the SMTC window configuration and SSB reception time differ for different satellite cells, such as between satellite cells at different locations. Reducing the measurement gap size allows more time to be spent communicating with the serving cell rather than measuring the neighboring cell. However, due to the small measurement gap size, there is a higher risk that the terminal will not be able to acquire the SSB of the neighboring satellite cell for Radio Resource Management (RRM) measurements for neighboring cells at different or the same frequency. The SMTC window duration is at most 5ms, and depending on the initial position of the neighboring satellite cell's SSB within the SMTC window, a statically configured SMTC window cannot accommodate larger variations in propagation delay. Measuring the neighboring satellite cell is challenging with current SMTC configuration options because the terminal is not required to monitor the SSB outside the configured SMTC window.

[0023] Variations in propagation delay exist for handovers between LEO satellites orbiting at the same altitude, are more pronounced for handovers between LEO satellites orbiting at different altitudes, and are even more pronounced for handovers between LEO satellites and geostationary Earth orbit (GEO) satellites. Furthermore, due to differences in position, each terminal experiences different variations in propagation delay over the same time period between the same satellites. As described in R2-2010795 below, the SMTC window should be improved for NTN systems because it needs to accommodate delay variations between serving and neighboring cells / satellites. "In the typical case of a TN system, the SSB burst signal generated by a neighboring cell is always detectable within the corresponding SMTC window configured via the serving cell. Outside the configured corresponding SMTC window, the UE does not need to measure the SSB burst signal. However, for NTN systems, analysis reveals that the SSB burst signal generated by a neighboring cell may be outside the corresponding SMTC window configured via the serving satellite. If the UE has the ability to capture the difference in propagation delay between the serving and neighboring satellites, even if the SSB burst signal is outside the configured corresponding SMTC window, the UE can still know when to detect the actual SSB burst signal generated by the neighboring cell. If RAN2 does not want improvements to the SMTC configuration for NTN, the UE should be allowed to search for the SSB burst signal generated by the neighboring cell even outside the configured corresponding SMTC window." The SMTC window for SSB measurements established by the serving cell should attempt to account for all possible SSB delays for all connected terminals.

[0024] Figures 1A and 1B are schematic diagrams of a system for compensating satellite signal propagation delay variations according to at least one embodiment of the present invention. Figure 1A shows the system at an earlier time, and Figure 1B shows the system at a later time.

[0025] In Figures 1A and 1B, satellite 120A, flying in LEO, is currently providing communications for NTN Gateway 110A, which is the serving cell of Terminal 100, while satellite 120B, flying in LEO at a higher altitude than satellite 120A, is providing communications for NTN Gateway 110B, which is a potential target neighbor cell. In this scenario, satellite 120A is moving away from Terminal 100 along orbit 122A, and satellite 120B, on a different orbit 122B, is moving towards Terminal 100. The propagation delay between satellite 120A and Terminal 100 is expressed as dSAT1-UE(t) (i.e., a function of time t), and the delay between satellite 120B and Terminal 100 is expressed as dSAT2-UE(t). In some embodiments, satellites 120A and 120B do not support the NR protocol and instead simply relay signals from the ground gateways, NTN Gateway 110A and NTN Gateway 110B, respectively. Such satellites are described as "transparent" in some examples. In some embodiments with transparent satellites, the propagation delay also depends on the relative positions of the gateway cells, which are NTN gateways 110A and 110B in some embodiments. In some embodiments, satellite 120A includes a serving cell of the cellular network, and satellite 120B includes a neighbor cell of the cellular network. Both fully support the NR protocol and function as satellite cells. Satellite 120A is moving toward the connected NTN gateway 110A, and satellite 120B is moving toward the connected NTN gateway 110B. Figure 1A shows the relative positions of the satellites at the first time t1, and Figure 1B shows the relative positions of the satellites at the second time t2. Figure 1B shows that at time t2, satellite 120A has moved a distance of 124A, and satellite B has moved a distance of 124B. The propagation delays between the satellite and the gateway are dSAT1-GW1(t) and dSAT1-GW2(t), respectively.

[0026] For satellite movement, the propagation delay varies with time. Table 1 provides numerical examples based on the estimated elevation angles between satellite cells and ground objects in one embodiment where satellite 120A is flying at an altitude of 600 km, satellite 120B is flying at an altitude of 1500 km, and both satellite 120A and satellite 120B are transparent.

Table 1

[0027] The timing of terminal 100 is based on the serving cell (NTN gateway 110 communicating through satellite 120A in FIGS. 1A and 1B). For this reason, terminal 100 is exposed to the drift of the SSB from satellite 120B.

[0028] Based on the geometric arrangements shown in FIG. 1 and Table 1, the total propagation delay between NTN gateway 110A and terminal 100 varies from about 5.1 ms to about 6.1 ms, and the total propagation delay between NTN gateway

[0029] 110B and terminal 100 decreases from about 13.4 ms to about 10.6 ms. Thus, the difference in the total propagation delay between the connection through satellite 120A and the connection through satellite 120B observed by terminal 100 varies from 8.3 ms at t1 to 5.5 ms at t2. Thus, the SSB from NTN gateway 110B adjusted to reach at t1 within the SMTC window according to the configuration established by NTN gateway 110A is actually outside the SMTC window at t2.

[0029] FIGS. 2A and 2B are diagrams showing the relative timing between a measurement window and a measurement signal according to at least one embodiment of the present invention. FIG. 2A shows the relative timing at a previous time such as t1 in FIG. 1A, and FIG. 2B shows the relative timing at a later time such as t2 in FIG. 1B.

[0030] Figure 2A shows the intended timeline 236 when the measurement windows and measurement signals are adjusted. As a result of the adjustment, measurement window 230A opens at time 232A, and measurement signal 237A sent at time 238A is received before measurement window 230A closes. Similarly, measurement window 230B opens at time 232B, and measurement signal 237B sent at time 238B is received before measurement window 230B closes.

[0031] Figure 2B shows the resulting timeline 236 for the changes in propagation delay caused by the satellite orbits shown in Figures 1A and 1B. Because the total propagation delay between NTN Gateway 110A (serving cell) and Terminal 100 changes from approximately 5.1 ms to approximately 6.1 ms, the measurement window 230A begins at time 232A after a 1 ms delay 233A. Because the total propagation delay between NTN Gateway 110B (neighboring cell) and Terminal 100 changes from approximately 13.4 ms to approximately 10.6 ms, the measurement signal 237A begins at time 238A with a 2.8 ms forward 239A. This results in the measurement signal 237A reaching Terminal 100 outside of the measurement window 230A. Unless compensated, Terminal 100 will not receive the measurement signal 237A. The measurement window 230B and the measurement signal 237B are substantially affected in a similar manner.

[0032] Figure 3 shows an operation flow for detecting satellite signal propagation delay variations according to at least one embodiment of the present invention. In some embodiments, the operation flow provides a method for detecting satellite signal propagation delay variations by a serving cell communicating with a terminal. In some embodiments, the operation is performed by a detection section or a subsection of the serving cell communicating with the terminal.

[0033] In S340, the detection section or its subsections send satellite orbit data and cell measurement window specifications to the terminal. If multiple terminals are connected to the serving cell, the detection section sends orbit data and cell measurement window specifications to all connected terminals. In situations like those shown in Figures 1A and 1B, where multiple serving cells and neighboring cells are using the satellite to communicate with the terminal, orbit data for each satellite is sent to the terminal.

[0034] In some embodiments, the cell measurement window specification includes periodicity, duration, and offset. In some embodiments where cell measurements are performed according to the SMTC protocol, the serving cell defines the cell measurement window specification to which neighboring cells send cell measurement signals. In these embodiments, the cell measurement window specification includes periodicity mgrp, gap duration mgl, gap timing advance mgta, and offset gapOffset. In these embodiments, since the measurement window is a time frame within a gap with non-transmission time on either side, the gap duration mgl effectively sets the duration of the measurement window. Also, in embodiments of the SMTC protocol, the offset gapOffset is in the range of 0 to 1 times smaller than the periodicity mgrp. For example, if mgrp is 80, the range of gapOffset is from 0 to 79. In the SMTC protocol and other embodiments, the cell measurement window specification is transmitted through radio resource control (RRC) signaling as part of MeasConfig.

[0035] In some embodiments, orbital data represents satellite position, satellite velocity, and reference position. In some embodiments where the satellite is transparent, the orbital data further represents the gateway position. In some embodiments, orbital data is also transmitted via RRC signaling. In these and some other embodiments, the range and resolution of each value in the orbital data may affect spectral efficiency and accuracy. In some embodiments, satellite position is three coordinate values ​​utilizing 84 bits with a range of ±50,000 km and a resolution of 0.4 m, satellite velocity is three scalar values ​​utilizing 60 bits with a range of ±8 km / s and a resolution of 0.015 km / s, and reference position is three coordinate values ​​utilizing 75 bits with a range of ±6,500 km and a resolution of 0.4 m. In the SMTC protocol and other embodiments, orbital data is transmitted via Radio Resource Control (RRC) signaling as part of MeasObjectNR.

[0036] In some embodiments, the detection section further sends one or more report conditions. In some embodiments, the report conditions include delayed report periodicity, delay difference threshold, and gap sequence value. In some embodiments, the delayed report periodicity is significantly greater than the measurement window periodicity (e.g., greater than 1000 ms). In some embodiments, the delay difference threshold can be used to determine whether the terminal sends a report or whether the report includes a suggestion. In some embodiments, two delay difference thresholds are used so that an alert is issued when the delay difference exceeds a higher threshold between 1 ms and 1000 ms, and the alert remains active until the delay difference falls below a lower threshold between 1 ms and 1000 ms. Having a higher activation threshold and a lower deactivation threshold leads to a reduction in false positives and false negatives. In some embodiments, the gap sequence determines which neighboring cells send in the same gap period or in which gap within the measurement window. In some embodiments where the terminal performs more analysis, the report condition is the terminal's determination that the measurement signal arrives at the terminal outside the time frame defined by the cell measurement window specification. In some embodiments, the detection section instructs the terminal to send a report in all cases. In the SMTC protocol and other embodiments, report conditions are sent via radio resource control (RRC) signaling as part of MeasObjectNR.

[0037] In S342, the detection section or its subsection receives an indication from the terminal that the cell measurement signal will arrive at the terminal outside the time frame defined by the cell measurement window specification. In some embodiments, the indication is received via RRC signaling. In some embodiments, the indication includes information representing the offset between the measurement window and the measurement signal as detected by the terminal that sent the indication, information enabling the serving cell to determine the offset between the measurement window and the measurement signal as detected by the terminal that sent the indication, or any other information that can be used by the serving cell to determine appropriate compensation. In some embodiments, the indication includes confirmation that the cell measurement signal will arrive at the terminal within the time frame defined by the cell measurement window specification. In some embodiments, the indication includes a delay difference value representing the difference in propagation delay between the serving cell and neighboring cells in the cellular network. In situations where several of the neighboring cells are using satellites to communicate with the terminal, multiple indications may be received from the terminal. If multiple terminals are connected to the serving cell, the detection section may receive one or more indications from each connected terminal. In some embodiments, the indication includes the geographical location of the terminal, and in some of these embodiments, there is no other information.

[0038] In S344, the detection section or its subsection determines whether all suggestions have been received, in accordance with the measurement window specification and the transmission of trajectory data. In some embodiments, the detection section refers to a time limit within which the terminal must send a suggestion or other criteria for determining whether all suggestions to be considered have been received. In some embodiments, the terminal sends a suggestion regardless of whether the cell measurement signal reaches the terminal within the time frame defined by the cell measurement window specification, and the detection section waits until a suggestion is received from each connected terminal. If the detection section determines that all suggestions have been received according to the criteria, the operation flow proceeds to S346 to continue the detection process. If the detection section determines that the criteria have not been met, the operation flow returns to S342 to receive further suggestions.

[0039] In S346, the detection section or its subsection determines the relative timing between the measurement window detected by the connected terminal and the measurement signals of any neighboring cells. In some embodiments, the connected terminal directly provides the relative timing in the suggestion received in S342. In some embodiments, the detection section determines whether there is overlap based on other information provided by the terminal in the suggestion received in S342. In some embodiments, where the suggestion received in S342 includes the geographical location of the terminal, the detection section performs all calculations necessary to make a determination for each terminal for each neighboring cell. If the detection section determines that all measurement signals detected by the terminals in all received suggestions are received within the measurement window, the operation flow ends without further operations for compensation. If the detection section determines that the measurement signals are received outside the measurement window of the connected terminal, the operation flow proceeds to S360 to perform compensation. In some embodiments, the decision in S346 is not based on whether a single measurement signal reaches a single terminal outside the measurement window, but rather on threshold amounts such as terminals, neighboring stations, and some weighted element criteria.

[0040] In S360, the serving cell compensation section compensates for measurement signals that reach the terminal outside the measurement window defined by the measurement window specification sent in S340. In some embodiments, the compensation section or its subsections modify the cell measurement window specification so that the cell measurement signals sent from the satellite reach the terminal within the time frame defined by the cell measurement window specification. Several embodiments of the compensation operation in S360 are described in more detail with reference to Figure 5.

[0041] Figure 4 shows an operation flow for reporting satellite signal propagation delay variations according to at least one embodiment of the present invention. In some embodiments, the operation flow provides a method for reporting satellite signal propagation delay variations by a terminal connected to a serving cell. In some embodiments, the operation is performed by a reporting section or a subsection of the terminal.

[0042] In S450, the report section or its subsection receives satellite orbit data and cell measurement window specifications from the cellular network's serving cell. The satellite orbit data and cell measurement window specifications are substantially the same as those described in relation to S340 in Figure 3. In some embodiments, the report section also receives report conditions, such as the report conditions described in relation to S340 in Figure 3, or commands to send a report in any case.

[0043] In S452, the report section or its subsections determines the propagation delay of each neighboring cell. In some embodiments, the report section determines the difference in propagation delay between the serving cell and neighboring cells of the cellular network based on orbital data and the geographical location of the terminal. In some embodiments, the determination section obtains the geographical location from a Global Positioning System (GPS) chip in the terminal, direct user input, or other methods that do not use the cellular network. Thus, the report section makes a determination without providing the geographical location of the terminal to the cellular network or enabling the cellular network to obtain the geographical location of the terminal. In some embodiments, the report section does not make determinations other than differences in propagation delay, such as those based on reporting conditions based on differences in propagation delay. In some embodiments, the report section also reports propagation delay variations because the propagation delay may differ in the time it takes for the measured signal to reach the terminal. In some embodiments, the serving cell is a non-terrestrial gateway that communicates with the terminal via satellite. In some of these embodiments, the report section further determines the difference in propagation delay based on the geographical location of the non-terrestrial gateway.

[0044] In some embodiments, the reporting section uses propagation delay to further determine, for example, whether the cell measurement signal arrives outside the time frame defined by the cell measurement window specification, depending on the reporting conditions based on such determination. In some situations, the reporting section determines that the cell measurement signal arrives outside the time frame defined by the cell measurement window specification.

[0045] In S454, the report section or its subsection determines whether the report conditions are met. In some embodiments, the report section refers to report conditions or report instructions received from the serving cell along with the cell measurement window specification and trajectory data. In some embodiments, the report section refers to internal report conditions. In some embodiments, where the report condition is a delay difference threshold, the report section determines, for each neighboring cell, whether the difference in propagation delay between the neighboring cell and the serving cell exceeds the delay difference threshold. If the report section determines that the report conditions are met, the operation flow proceeds to S456 to send the report. If the report section determines that the report conditions are not met, the operation flow ends without sending a report.

[0046] In S456, the report section or its subsections sends a report to the serving cell. In some embodiments, the report is sent via RRC signaling. In some embodiments, the report section sends a suggestion to the serving cell that the cell measurement signal was received outside the window defined by the cell measurement window specification. In some embodiments, the report includes a suggestion that the difference in propagation delay between neighboring cells and the serving cell exceeds a delay difference threshold. In some embodiments, the report suggests that the reporting conditions were not met, such as when the serving cell instructs the terminal to send a report under any circumstances.

[0047] Figure 5 shows an operation flow for compensating satellite signal propagation delay variations according to at least one embodiment of the present invention. In some embodiments, the operation flow provides a method for compensating satellite signal propagation delay variations by a serving cell. In some embodiments, the operation is performed by a compensation section or a subsection of the serving cell.

[0048] In S562, the compensation section or its subsection modifies the cell measurement window specification. In some embodiments, the compensation section modifies at least one of the periodicity, duration, and offset. In some embodiments, the compensation section specifies additional measurement window specifications, such as an additional measurement window having periodicity, duration, and offset. In some embodiments, the compensation section determines a modification to ensure that at least one measurement signal from all neighboring cells reaches all connected terminals within a time frame defined by the measurement window specification. In some embodiments, the compensation section determines a modification to ensure that at least one measurement signal from most neighboring cells reaches most connected terminals within a time frame defined by the measurement window specification. In some embodiments, the compensation section determines another modification for each neighboring cell, each communication channel, or each frequency band.

[0049] In S564, the compensation section or its subsection determines the spectral efficiency of the cell measurement window specification modified in S562. In some embodiments, spectral efficiency is the result of measuring the amount of bandwidth consumed by a terminal for the purpose of establishing and maintaining network communication. In some embodiments, where neighboring cells communicate on different frequencies from the serving cell, this directly relates to the amount of time required to establish and maintain network communication, such as the waiting time for receiving the measurement signal. In some embodiments, the compensation section determines a different spectral efficiency for each neighboring cell, each communication channel, or each frequency band.

[0050] In S566, the compensation section or its subsection determines whether the spectral efficiency is acceptable. In some embodiments, the compensation section determines whether the spectral efficiency of the cell measurement window specification modified in S564 is acceptable by comparing the spectral efficiency with a spectral efficiency threshold. If the compensation section determines that the spectral efficiency of the cell measurement window specification modified in S564 is acceptable, the operation flow proceeds to the transmission of the modified measurement window specification in S568. If the compensation section determines that the spectral efficiency of the cell measurement window specification modified in S564 is not acceptable, the operation flow proceeds to further modification of the measurement window specification in S562.

[0051] As the iterations of S562, S564, and S566 progress, different modifications are attempted until an acceptable spectral efficiency is achieved. In some embodiments where spectral efficiency is compared to a spectral efficiency threshold, modifying the cell measurement window specification includes determining that the spectral efficiency of the modified cell measurement window specification exceeds the spectral efficiency threshold. In some embodiments, an algorithm or formula is used to determine the modification that has the greatest spectral efficiency. In some embodiments, an algorithm or formula is used to determine a modification of the cell measurement window specification that balances spectral efficiency with the reception of measurement signals. For example, a modification that allows at least one measurement signal from all neighboring cells to reach all connected terminals significantly reduces spectral efficiency, especially in situations where many connected terminals are present.

[0052] In S568, the compensation section or its subsection sends the cell measurement window specification modified in S562 to the connected terminal. In some embodiments, the modified cell measurement window specification is sent via RRC signaling. In some embodiments, the modified cell measurement window specification is substantially the same as that sent in S340 in Figure 3, but without trajectory data and report conditions. In some embodiments, the modified cell measurement window specification includes further modifications for each neighboring cell, each communication channel, or each frequency band.

[0053] Figure 6 shows the relative timing between a measurement window and a measurement signal with a modified duration according to at least one embodiment of the present invention. The timeline 636 includes the relative timing at a later time, such as t2 in Figure 1B. Similar to the description with respect to Figure 2B, the total propagation delay between the NTN gateway 110A (serving cell) and terminal 100 changes from about 5.1 ms to about 6.1 ms, so the measurement window 630A begins at time 632A after a 1 ms delay 633A. The total propagation delay between the NTN gateway 110B (neighboring cell) and terminal 100 changes from about 13.4 ms to about 10.6 ms, so the measurement signal 637A begins at time 638A with a 2.8 ms forward 639A. However, instead of the measurement signal 637A reaching terminal 100 outside of the measurement window 630A, the cell measurement window specification is modified by the serving cell to have a longer duration. Because of this change, the measurement window 630A still begins at time 632A, but is open long enough to include time 638B when the measurement signal 637B reaches terminal 100.

[0054] In some embodiments, the measurement signal is brought forward and the measurement window is delayed from the terminal's perspective. The increase in the duration of the measurement window ensures that subsequent measurement signals fall within the measurement window. In such cases, unless the sum of the measurement signal forwarding and the measurement window delay is greater than half of the periodicity, the increase in the duration used to capture subsequent measurement signals reduces spectral efficiency to below 50%. In other words, the terminal consumes more than half of its connection time or bandwidth simply to maintain network connectivity. A spectral efficiency of below 50% may be unacceptable in many embodiments, and modifying the cell measurement window specification to increase the duration has a higher probability of resulting in acceptable spectral efficiency in other situations. For example, in some embodiments where the measurement signal is delayed and the measurement window is brought forward from the terminal's perspective, modifying the cell measurement window specification to increase the duration has a higher probability of resulting in acceptable spectral efficiency.

[0055] Figure 7 shows the relative timing between the measurement window and the measurement signal with a modified offset according to at least one embodiment of the present invention. The timeline 736 includes the relative timing at a later time, such as t2 in Figure 1B. Similar to the description with respect to Figure 2B, the total propagation delay between the NTN gateway 110B (neighboring cell) and terminal 100 changes from about 13.4 ms to about 10.6 ms, so the measurement signal 737A starts at time 738A by being brought forward by 2.8 ms 739A. The total propagation delay between the NTN gateway 110A (serving cell) and terminal 100 changes from about 5.1 ms to about 6.1 ms. However, with the modification, an offset 731A is introduced in the cell measurement window specification. As a result, the measurement window 730A starts at time 732A after the offset 731A, so the measurement window 730A includes time 738B when the measurement signal 737B reaches terminal 100.

[0056] In some embodiments, from the terminal's perspective, the measurement signal is brought forward and the measurement window is delayed. The introduction of an offset in the measurement window, which is also a substantial increase in the offset from zero to a positive value, ensures that subsequent measurement signals fall within the measurement window. Since the duration and periodicity of the measurement window are constant and no other windows are introduced, the spectral efficiency is also constant. In other words, the terminal does not consume more connection time or bandwidth just to maintain network connectivity than before the offset was introduced. The invariant spectral efficiency after changing the cell measurement window specification is more likely to be acceptable than the reduced spectral efficiency. However, in some embodiments where many terminals are connected to a serving cell where many neighboring cells communicate via satellite, the relative timing between the measurement signal and the measurement window from the perspective of different connected terminals is brought forward and delayed by different amounts in different directions. Therefore, changes in the cell measurement window specification to introduce or increase the offset are less likely to significantly increase the amount of neighboring cells sending at least one measurement signal to reach connected terminals in embodiments involving many terminals, many satellites, or both.

[0057] Figure 8 shows the relative timing between a modified periodicity measurement window and a measurement signal according to at least one embodiment of the present invention. The timeline 836 includes the relative timing at a later time, such as t2 in Figure 1B. Similar to the description with respect to Figure 2B, the total propagation delay between the NTN gateway 110A (serving cell) and terminal 100 changes from about 5.1 ms to about 6.1 ms, so the measurement window 830A begins at time 832A after a 1 ms delay 833A. The total propagation delay between the NTN gateway 110B (neighboring cell) and terminal 100 changes from about 13.4 ms to about 10.6 ms, so the measurement signal 837A begins at time 838A with a 2.8 ms forward 839A. However, instead of the measurement signal 837A reaching terminal 100 outside a certain measurement window, the cell measurement window specification is modified by the serving cell to have a shorter periodicity. Due to this change, the measurement window 830A still begins at time 832A and ends before the measurement signal 837B reaches terminal 100, but due to the decrease in periodicity, another measurement window 834B is open when the measurement signal 837B reaches terminal 100.

[0058] In some embodiments, from the terminal's perspective, the measurement signal is brought forward and the measurement window is delayed. The decrease in the periodicity of the measurement window, which is a substantial increase in the ratio of the measurement window with respect to time, reduces spectral efficiency because connected terminals spend more time waiting for the measurement signal. However, in some embodiments where many terminals are connected to a serving cell where many neighboring cells communicate via satellite, a change in the cell measurement window specification to double the ratio of the measurement window has a greater potential to significantly increase the number of neighboring cells sending at least one measurement signal to the connected terminal than a change that does not increase the amount of time spent waiting for the measurement signal on connected terminals.

[0059] Figure 9 shows the initial measurement window, additional measurement window, and relative timing between measurement signals as configured in at least one embodiment of the present invention. The timeline 936 includes relative timing at times after t2, etc., in Figure 1B. Similar to the description with respect to Figure 2B, as the total propagation delay between NTN Gateway 110A (serving cell) and Terminal 100 changes from about 5.1 ms to about 6.1 ms, the measurement window 930A begins at time 932A after a 1 ms delay 933A. As the total propagation delay between NTN Gateway 110B (neighboring cell) and Terminal 100 changes from about 13.4 ms to about 10.6 ms, the measurement signal 937A begins at time 938A with a 2.8 ms forward 939A. However, instead of the measurement signal 937A reaching Terminal 100 outside of a certain measurement window, the cell measurement window specification is modified by the serving cell to have an additional measurement window specification. In some embodiments, the additional window measurement specification includes periodicity, duration, and offset having different values ​​in addition to the periodicity, duration, and offset of the initial window measurement specification. Due to this modification, the measurement window 930A still begins at time 932A and ends before the measurement signal 937B reaches terminal 100, but the additional window measurement specification opens another measurement window 935 when the measurement signal 937B reaches terminal 100.

[0060] In some embodiments, the measurement signal is brought forward and the measurement window is delayed from the terminal's perspective. An additional window measurement specification that effectively adds a measurement window reduces spectral efficiency because connected terminals spend more time waiting for the measurement signal. However, in some embodiments where many terminals are connected to a serving cell where many neighboring cells communicate via satellite, a modification of the cell measurement window specification to add a measurement window has a greater potential to significantly increase the number of neighboring cells sending at least one measurement signal to the connected terminal than a modification that does not increase the amount of time spent waiting for the measurement signal on the connected terminal.

[0061] Figure 10 shows an operation flow for further compensating for satellite signal propagation delay variations according to at least one embodiment of the present invention. In some embodiments, the operation flow provides a method for compensating for satellite signal propagation delay variations by a terminal connected to a serving cell. In some embodiments, the operation is performed by a compensation section or a subsection of the terminal.

[0062] In S1070, the compensation section or its subsection receives the modified window measurement specification from the serving cell. In some embodiments, the modified window measurement specification is received through RRC signaling. In some embodiments, the modified cell measurement window specification is modified as described in S562 of Figure 5.

[0063] In S1072, the compensation section or its subsection determines whether the measurement signal of any neighboring cell reaches outside the measurement window defined by the modified cell measurement window specification. Some connected terminals determine that the modified cell measurement window specification results in measurement signals from one or more neighboring cells reaching outside the measurement window, because the modification to the cell measurement window specification to ensure that at least one measurement signal from all neighboring cells reaches all connected terminals results in unacceptable spectral efficiency in some situations. If the compensation section determines that the measurement signals from one or more neighboring cells reach outside the measurement window, the operation flow proceeds to the individual measurement window configuration in S1074. If the compensation section determines that at least one measurement signal from all neighboring cells reaches within the measurement window, the operation flow ends without performing individual measurement configurations.

[0064] In S1074, the compensation section or its subsections constitute individual measurement windows. In some embodiments, the compensation section constitutes individual measurement window specifications that define one or more time frames in which only the individual terminal waits for the arrival of the measurement signal. During the time frames defined by the individual measurement window specifications, the serving does not communicate with the terminal but continues to communicate with other terminals. Thus, individual measurement window specifications result in significantly less reduction in spectral efficiency for cells and other terminals than terminals that constitute individual measurement window specifications. In some embodiments, the measurement signal is brought forward and the measurement window is delayed from the perspective of the terminal, the compensation section constitutes individual measurement windows similar to the measurement window 935 in Figure 9. In some embodiments, individual measurement window specifications include periodicity, duration, and offset, which may be configured to receive multiple measurement signals from different neighboring cells. In some embodiments, only the individual measurement window specifications include a start time and duration, and the individual measurement window specifications result in a single individual measurement window, which has a higher potential to result in higher spectral efficiency in embodiments that result in multiple individual measurement windows but allow for the reception of fewer measurement signals.

[0065] In S1076, the compensation section or its subsection sends a report of individual measurement window specifications to the serving cell. In some embodiments, individual measurement window specifications are sent via RCC signaling.

[0066] In S1078, the compensation section or its subsection receives confirmation from the serving cell. In some embodiments, the confirmation received from the serving cell confirms that the serving cell will not communicate with the terminal during any time frame defined by the individual measurement window specifications. In other words, the serving cell provides a measurement gap for the terminal that coincides with any time frame defined by the individual measurement window specifications. In some embodiments, the confirmation is received via RCC signaling.

[0067] In some embodiments, the serving cell may perform operations S1072, S1074, S1076, and S1078. In some of these embodiments, the computational load on the serving cell increases, leading to the serving cell utilizing more computational resources. In some of these embodiments, the terminal sends more detailed information to the serving cell regarding the measurement window and the relative timing of the measurement signals, for example, during the transmission of a propagation delay report similar to operation S456 in Figure 4. In some of these embodiments, the serving cell sends individual cell measurement window specifications to each terminal during the transmission of a modified cell measurement window specification similar to operation S568 in Figure 5.

[0068] Figure 11 shows a further operation flow for compensating satellite signal propagation delay variations according to at least one embodiment of the present invention. In some embodiments, the operation flow provides a method for compensating satellite signal propagation delay variations by a terminal connected to a serving cell. In this embodiment, the operation is performed by a system including a serving cell 1110 and a terminal 1100 connected to the serving cell 1110. In some embodiments, the transmission between the serving cell 1110 and the terminal 1100 is performed through RRC signaling.

[0069] Serving cell 1110 sends measurement window specifications and orbital data 1140 to terminal 1100. In some embodiments, serving cell 1110 also sends reporting conditions. Terminal 1100 receives the window specifications and orbital data 1140 and determines the delay propagation for each cell communicating with terminal 1100 through the satellite. Depending on whether it determines a significant difference in delay propagation between serving cell 1110 and any neighboring cell, or whether it determines that other reporting conditions specified by the serving cell are met, terminal 1100 sends a delay propagation report 1156 to the serving cell. In some embodiments, the delay propagation report includes more detailed information than the propagation delay value, such as the measurement window and relative timing of the measurement signals as seen from terminal 1100. Serving cell 1110 receives the delay propagation report 1156 and modifies the cell measurement window specifications in response to the delay propagation report 1156, which includes an indication that the measurement signals of one or more neighboring cells do not reach terminal 1100 during any of the time frames defined by the cell measurement window specifications. In some embodiments, the serving cell 1110 attempts to modify the cell measurement window specification so that at least one measurement signal from all neighboring cells reaches the measurement window as seen from terminal 1100, but no modification is made that achieves this with acceptable spectral efficiency. The serving cell 1110 sends a modified cell measurement window specification 1168 to terminal 1100 that prevents measurement signals from all neighboring cells from reaching the measurement window as seen from terminal 1100. Upon receiving the modified cell measurement window specification 1168, terminal 1100 configures individual cell measurement window specifications 1176 to define a measurement window for receiving at least one measurement signal from any neighboring cell that does not reach within any time frame defined by the modified cell measurement window specification 1168. Terminal 1100 sends the individual cell measurement window specifications 1176 to the serving cell 1110. Serving cell 1110 responds by sending a synchronization measurement gap 1169 that confirms that serving cell 1110 provides a measurement gap that is synchronized with the time frame defined by the individual cell measurement window specification 1176.

[0070] In some embodiments of the system, the serving cell 1110 does not send orbital data, does not collect propagation delay reports, or does not receive individual cell measurement window specifications. Instead, in these embodiments, each connected terminal, such as terminal 1100, sends its geographical location to the serving cell 1110. In some of these embodiments, the serving cell 1110 makes all decisions based on this information, including determining whether a change in the cell measurement window specification is necessary, determining changes to the cell measurement window specification, and determining individual cell measurement window specifications. In such embodiments, the serving cell 1110 utilizes more computing resources than the connected terminals, resulting in greater energy efficiency for the connected terminals. However, in some embodiments where the connected terminals perform more decisions, energy consumption is balanced more than in some embodiments where the serving cell 1110 performs all decisions. Also, in some embodiments where terminal 1100 is located in a geographical area where network collection of individual geographical locations is prohibited, terminal 1100 may not have the ability to send its geographical location to the serving cell 1110. Furthermore, in some embodiments where only connected terminals send geographical location information, it is not possible to use reporting conditions that require terminal determination, which require all terminals to send geographical location information at all times, not only when the delay becomes significant or exceeds a threshold.

[0071] Figure 12 is a block diagram of an exemplary hardware configuration of a serving cell for satellite signal propagation delay variation compensation according to at least one embodiment of the present invention. The exemplary hardware configuration includes a serving cell 1210A that communicates with terminal 1200 and neighboring cells 1210B, 1210C, 1210D, and 1210E through a cellular network 1226.

[0072] The serving cell 1210A includes a controller 1212, a storage unit 1214, and a communication interface 1216. In some embodiments, the controller 1212 and the storage unit 1214 are part of a client computer, a computer system including multiple computers, or a server mainframe that connects directly to the serving cell 1210A.

[0073] In some embodiments, the controller 1212 is a processor or programmable circuit that executes instructions causing a processor or programmable circuit to perform an operation according to those instructions. In some embodiments, the controller 1212 is an analog or digital programmable circuit, or any combination thereof. In some embodiments, the controller 1212 consists of physically separate storage or circuitry that interact through communication. In some embodiments, the storage unit 1214 is a non-volatile computer-readable medium capable of storing executable and non-executable data for access by the controller 1212 during instruction execution. The communication interface 1216 sends and receives data to and from the network 1226.

[0074] The controller 1212 includes a detection section 1280 and a compensation section 1282. The storage unit 1214 includes orbital data 1284, cell measurement window specifications 1286, and compensation parameters 1288.

[0075] The detection section 1280 is a circuit or command of the controller 1212 that detects whether a connected terminal, such as terminal 1200, has measurement signals from neighboring cells, such as 1210B, 1210C, 1210D, and 1210E, that reach the connected terminal within a time frame defined by the cell measurement window specification. In some embodiments, the detection section 1280 utilizes information in the storage unit 1214, such as trajectory data 1284 and the cell measurement window specification 1286. The detection section 1280 may include subsections for performing additional functions, as described in the flowchart above. Such subsections may be represented by names associated with their functions.

[0076] The compensation section 1282 is a circuit or instruction of the controller 1212 that performs satellite signal propagation delay variation compensation. In some embodiments, the compensation section 1282 modifies the cell measurement window specification to increase the reception of neighbor cell measurement signals with acceptable spectral efficiency. While performing compensation, in some embodiments, the compensation section 1282 utilizes information in the storage unit 1214, such as the cell measurement window specification 1286 and compensation parameters 1288. The compensation section 1282 may include subsections for performing additional functions, such as those described in the flowchart above. Such subsections may be represented by their functions and associated names.

[0077] In other embodiments, the serving cell includes, or can directly communicate with, other devices capable of handling the logical functions for performing the operations herein. In some embodiments, the controller and the storage unit share a circuit or one or more computer-readable media rather than being entirely separate devices. In some embodiments, the storage unit may be a hard drive that stores both computer-executable instructions and data accessed by the controller, and the controller may be a combination of a central processing unit (CPU) and RAM to which all or some of the computer-executable instructions may be copied for execution by the CPU during the performance of the operations herein.

[0078] In embodiments where a serving cell utilizes a computer to perform the operations described herein, a program installed on the computer causes the computer to function as an operation associated with the serving cell of the embodiment described herein, or to perform such an operation. In some embodiments, such a program may be executed by a processor to cause the computer to perform specific operations associated with some or all of the blocks in the flowchart and block diagram described herein.

[0079] Figure 13 is a block diagram of an exemplary hardware configuration of a terminal for satellite signal propagation delay variation compensation according to at least one embodiment of the present invention. The exemplary hardware configuration includes a terminal 1300 that communicates with serving cell 1310A and neighboring cells 1310B, 1310C, 1310D, and 1310E through a cellular network 1326.

[0080] The terminal 1300 includes a controller 1302, a storage unit 1304, and a communication interface 1306. In some embodiments, the terminal 1300 is a mobile phone, a smartphone, a tablet, a notebook computer, or any other device having a cellular network communication interface.

[0081] In some embodiments, the controller 1302 is a processor or programmable circuit that executes instructions causing a processor or programmable circuit to perform an operation according to those instructions. In some embodiments, the controller 1302 is an analog or digital programmable circuit, or any combination thereof. In some embodiments, the controller 1302 consists of physically separate storage or circuitry that interact through communication. In some embodiments, the storage unit 1304 is a non-volatile computer-readable medium capable of storing executable and non-executable data for access by the controller 1302 during instruction execution. The communication interface 1306 sends and receives data to and from the network 1326.

[0082] The controller 1302 includes a report section 1390 and a compensation section 1392. The storage unit 1304 includes orbital data 1394, cell measurement window specifications 1396, and compensation parameters 1398.

[0083] The report section 1390 is a circuit or instruction of the controller 1302 that reports whether or not the measurement signals of any neighboring cells, such as neighboring cells 1310B, 1310C, 1310D, and 1310E, reach terminal 1300 during a time frame defined by the cell measurement window specification. In some embodiments, the report section 1390 utilizes information in the storage unit 1304, such as trajectory data 1394 and the cell measurement window specification 1396. The report section 1390 may include subsections for performing additional functions, as described in the flowchart above. Such subsections may be represented by names associated with their functions.

[0084] The compensation section 1392 is a circuit or instruction of the controller 1302 that performs satellite signal propagation delay variation compensation. In some embodiments, the compensation section 1392 constitutes individual cell measurement window specifications for receiving measurement signals from any neighboring cells that would not be received by the cell measurement window specification. While performing compensation, in some embodiments, the compensation section 1392 utilizes information in the storage unit 1304, such as the cell measurement window specification 1396 and compensation parameters 1398. The compensation section 1392 may include subsections for performing additional functions, such as those described in the flowchart above. Such subsections may be represented by names associated with their functions.

[0085] In other embodiments, the terminal includes other devices capable of processing the logical functions necessary to perform the operations herein. In some embodiments, the controller and the storage unit share a circuit or one or more computer-readable media rather than being entirely separate devices. In some embodiments, the storage unit may be a hard drive that stores both computer-executable instructions and data accessed by the controller, and the controller may be a combination of a central processing unit (CPU) and RAM, to which all or some of the computer-executable instructions may be copied for execution by the CPU during the performance of the operations herein.

[0086] In embodiments where a terminal utilizes a computer processor to perform the operations described herein, a program installed on the terminal causes the terminal to function as or perform the operations of the embodiments described herein. In some embodiments, such a program may be executed by the computer processor to cause the terminal to perform specific operations related to some or all of the blocks in the flowcharts and block diagrams described herein.

[0087] Various embodiments of the present invention are described with reference to flowcharts and block diagrams, where each block may represent (1) a processing step in which an operation is performed or (2) a section of a controller responsible for executing the operation. Specific steps and sections are implemented by dedicated circuits, programmable circuits supplied with computer-readable instructions stored on a computer-readable medium, and / or processors supplied with computer-readable instructions stored on a computer-readable medium. In some embodiments, the dedicated circuits may include digital and / or analog hardware circuits, and may include integrated circuits (ICs) and / or discrete circuits. In some embodiments, the programmable circuits may include reconfigurable hardware circuits such as field-programmable gate arrays (FPGAs) and programmable logic arrays (PLAs), which include logical AND, OR, XOR, NAND, NOR, and other logic operations, flip-flops, registers, memory elements, and the like.

[0088] Various embodiments of the present invention include systems, methods, and / or computer program products. In some embodiments, the computer program product includes a computer-readable storage medium (or medium) having computer-readable program instructions for causing a processor to perform aspects of the present invention.

[0089] In some embodiments, the computer-readable storage medium includes a tangible device capable of holding and storing instructions for use by an instruction execution device. In some embodiments, the computer-readable storage medium includes, but is not limited to, electronic storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination thereof. A non-exhaustive list of more specific examples of computer-readable storage media includes: portable computer diskettes, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disk read-only memory (CD-ROM), digital multipurpose disks (DVDs), memory sticks, floppy disks, mechanically encoded devices such as punch cards or raised structures in grooves on which instructions are recorded, and any suitable combination thereof. The computer-readable storage medium used herein is not interpreted as a transient signal itself, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a wave guide or other transmission medium (e.g., light pulses passing through a fiber optic cable), or electrical signals transmitted through a wire.

[0090] In some embodiments, the computer-readable program instructions described herein are downloadable from a computer-readable storage medium to each computing / processing device, or downloadable to an external computer or external storage device via a network such as the Internet, a local area network, a wide area network, and / or a wireless network. In some embodiments, the network may include copper transmission cables, optical transmission fibers, wireless transmissions, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and transfers the computer-readable program instructions for storage in a computer-readable storage medium within each computing / processing device.

[0091] In some embodiments, the computer-readable program instructions for performing the aforementioned operations are assembler instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including smalltalk, object-oriented programming languages ​​such as C++, and conventional procedural programming languages ​​such as the C programming language or similar programming languages. In some embodiments, the computer-readable program instructions are executed entirely on the user's computer, partially on the user's computer as a standalone software package, partially on the user's computer and partially on a remote computer, or fully on a remote computer or server. In some embodiments, in the latter scenario, the remote computer is connected to the user's computer through any type of network, including a local area network (LAN) or wide area network (WAN), or the connection may be to an external computer (e.g., via the Internet using an Internet Service Provider). In some embodiments, for example, an electronic circuit including a programmable logic circuit, a field-programmable gate array (FPGA), or a programmable logic array (PLA) executes a computer-readable program instruction by customizing the electronic circuit to perform aspects of the present invention using state information of the computer-readable program instruction.

[0092] Although embodiments of the present invention have been described, the technical scope of the claimed subject matter is not limited to the embodiments described above. It will be apparent to those skilled in the art that various modifications and improvements can be made to the embodiments described above. It will also be apparent from the scope of the claims that such modified or improved embodiments are included in the technical scope of the invention.

[0093] The operations, procedures, steps, and stages of each process performed by the apparatus, system, program, and method shown in the claims, embodiments, or figures may be performed in any order, unless the order is indicated by “before,” “prior,” etc., and unless the output from a previous process is used in a later process. The use of phrases such as “first” or “next” to describe a process flow in the claims, embodiments, or figures does not necessarily mean that the processes must be performed in that order.

[0094] According to at least one embodiment of the present invention, satellite signal propagation delay variations can be compensated by: sending satellite orbit data and cell measurement window specifications to the terminal, providing communication with the terminal to at least one of the serving cell and neighboring cells; receiving an indication from the terminal that the cell measurement signal will arrive at the terminal outside the time frame defined by the cell measurement window specifications; modifying the cell measurement window specifications based on differences in propagation delay between the serving cell defining the cell measurement window specifications and the neighboring cell sending the cell measurement signal, so that the cell measurement signal arrives at the terminal within the time frame defined by the cell measurement window specifications; and sending the modified cell measurement window specifications to the terminal.

[0095] Some embodiments include instructions in a computer program, methods performed by a processor that executes the instructions in the computer program, and a serving cell that performs the methods. In some embodiments, the serving cell includes a controller which includes circuitry configured to perform the operations in the instructions.

[0096] According to at least one embodiment of the present invention, satellite signal propagation delay variations can be compensated by receiving satellite orbit data and cell measurement window specifications from a serving cell of a cellular network, determining whether the cell measurement signal sent from a neighboring cell is received outside the time frame defined by the cell measurement window specifications based on the difference in propagation delay between the serving cell and neighboring cells, and sending a suggestion to the serving cell that the cell measurement signal is received outside the window defined by the cell measurement window specifications.

[0097] Some embodiments include instructions in a computer program, methods performed by a processor that executes the instructions in the computer program, and a terminal that performs the methods. In some embodiments, the terminal includes a controller that includes circuitry configured to perform operations in the instructions.

[0098] The above outlines some features of embodiments to enable those skilled in the art to better understand aspects of the disclosure. Those skilled in the art will understand that the disclosure can be used as a basis for designing or modifying other processes and structures to perform the same purposes and / or achieve the same advantages as the embodiments shown herein. Furthermore, those skilled in the art will recognize that such equivalent structures do not deviate from the spirit and scope of the disclosure, and that various changes, substitutions, and modifications can be made without deviating from the spirit and scope of the disclosure.

[0099] This application claims priority to U.S. Provisional Patent Application No. 63 / 137,916, filed on 15 January 2021, and U.S. Provisional Patent Application No. 63 / 140,578, filed on 22 January 2021, each described below and incorporated herein by reference in whole.

[0100] U.S. Provisional Patent Application No. 63 / 137,916

[0101] 3GPP TSG-RAN WG2 Meeting #113-e

[0102] E-Meeting: January 25th ~ February 5th, 2021

[0103] Agenda item: 8.10.3.3

[0104] Source: Rakuten Mobile

[0105] Title: SMTC and Measurement Gap Configuration for NTN

[0106] Document purpose: Discussion and decision-making

[0107] 1. Introduction The challenges to UE measurement caused by differences in propagation delay between satellites remain a subject of debate. The following agreements were reached during the offline discussions

[0106] [NTN]SMTC and Gap (Round 2): agreement: 1. Proposal 1: NTN's SMTC and gap configuration will be configured based on PCell timing. 2. RAN2 understands that, similar to the principles in TN, UEs are not compelled to detect SSB bursts outside the corresponding SMTC window configured in NTN. 3. Similar to TN, UEs should have a consistent understanding of measurement gaps to avoid unsynchronized behavior between UEs and networks, along with the network in NTN. This paper addresses an open problem and proposes a solution for SMTC window / gap configurations for SSB / CSI-RS measurement of neighboring cells (with fluctuating latency) when the network does not have accurate UE location information.

[0108] 2. Discussion

[0109] 2.1. Opinions on the existing proposal (R2-2010795) First, we would like to offer our views on existing proposals that require discussion. Proposal 2-1: RAN2 understands that the impact of inter-satellite latency differences on the SMTC configuration should be addressed by NTN. FFS: Is improvement of the SMTC configuration necessary at NTN? As described later in R2-2010795, the SMTC window should be improved for NTN systems because it needs to accommodate delay variations between serving and neighboring cells / satellites. "In the typical case of a TN system, the SSB burst signal generated by a neighboring cell is always detectable within the corresponding SMTC window configured via the serving cell. Outside the configured corresponding SMTC window, the UE does not need to measure the SSB burst signal. However, for NTN systems, analysis reveals that the SSB burst signal generated by a neighboring cell may be outside the corresponding SMTC window configured via the serving satellite. If the UE has the ability to capture the difference in propagation delay between the serving and neighboring satellites, even if the SSB burst signal is outside the configured corresponding SMTC window, the UE can still know when to detect the actual SSB burst signal generated by the neighboring cell. If RAN2 does not want improvements to the SMTC configuration for NTN, the UE should be allowed to search for the SSB burst signal generated by the neighboring cell even outside the configured corresponding SMTC window."

[0110] Proposal 1: The SMTC window should be improved for NTN systems because it needs to accommodate delay variations between serving and neighboring cells / satellites. Proposal 2-2: RAN2 first identifies the scenarios and discusses the severity of the impact before beginning improvements to the SMTC configuration at NTN.

[0111] Proposal 2: Improvements to NTN's SMTC configuration should be addressed in detail. Proposal 4: Due to NTN's SMTC window configuration, RAN2 cannot assume that the network always has accurate location information for the UE. Due to security and privacy concerns, even if satellites can obtain precise location data, national regulatory bodies may prohibit network providers from obtaining UE location data. Thus, it is unlikely that all networks always have the precise location of the UE.

[0112] Proposal 3: Agree with Proposal 4 in R2-2010795: Due to the SMTC window configuration at NTN, RAN2 cannot assume that the network always has accurate location information for the UE. Proposal 6-1: RAN2 understands that the impact of inter-satellite delay differences on the measurement gap configuration should be addressed by NTN. FFS: Is improvement of the measurement gap configuration necessary at NTN? If R2-2010795 demonstrates that improvements to the measurement gap configuration are necessary in NTN systems, the following options may be considered. Option 1: Extend the length of the measurement gap to ensure that the length is greater than or equal to the SSB periodicity. Option 2: Reuse the current signaling for measurement gap configuration (i.e., configure a measurement gap for each frequency), and the timing of the configured measurement gaps references the timing at the satellite or NTN GW. Based on the configured measurement gap, it is up to the UE / NW to acquire the measurement gap on the UE side, based on its position and the candidate satellite's orbit. Since the actual timing of the SMTC window on the UE side for cells on other satellites changes over time based on the satellite's movement, the NW needs to acquire the actual timing of the measurement gap on the UE side, based on the UE's position and the candidate satellite's orbit. Note: In this example, the measurement gap is maintained per satellite. Option 3: Configure multiple measurement gaps for each frequency, and the timing of the configured measurement gaps references the PCell timing on the UE side. Option 4: To prevent the UE from losing track of nearby satellite SSB bursts, extend the measurement gap length based on the difference in maximum propagation delay between the serving and nearby satellites. Option 5: Periodically apply measurement gap timing advance to detect all possible SSBs. Regarding Option 1, data cannot be scheduled during the measurement gap period, and extending the measurement gap period reduces spectral efficiency; therefore, extending the measurement gap should not be a priority discussion. A method is proposed for determining the measurement gap for a UE even when the gNB does not have UE location information, which can also be effectively used for other options such as Option 2 and Option 3. Assumption: 1) Based on Proposal 6-1 Option 2: "It is up to the UE / NW to obtain the measurement gap on the UE side based on its position and the candidate satellite's orbit. Since the actual timing of the SMTC window on the UE side for cells on other satellites changes over time based on the satellite's movement, the NW needs to obtain the actual timing of the measurement gap on the UE side based on the UE's position and the candidate satellite's orbit. Note: In this example, the measurement gap is maintained per satellite." 2) By agreement reached at RAN1 Meeting #103, it can be assumed that UEs always have their location information via GNSS.

[0113] Proposal 4: Agree on the following method for determining the measurement gap for a UE even when the gNB does not have UE location information. 1. gNB needs to send the trajectory of neighboring cells to the UE in RRC signaling as part of MeasObjectNR RRC. 2. The UE can calculate the propagation delay of nearby cells / satellites based on its position and nearby satellite orbits. 3. If the UE detects a significant RTD (> "X" ms) between the serving and nearby satellites, it notifies the gNB via an RRC message. 4. gNB constitutes a measurement gap for each neighborhood, or extends the measurement gap based on UE feedback. 5. The UE calculates the RTD for the neighbors after a pre-configured period "Y" indicated by the gNB, and if the RTD change for the neighbors is greater than "Z", it should report the RTD to the serving cell via an RRC message. Proposal 6-2: RAN2 first identifies the scenarios and discusses the severity of the impact before beginning to improve the measurement gap configuration at NTN. While the severity of the impact can be assessed in RAN2, it should be agreed that a solution is required to provide an appropriate configuration of the measurement gap / SMTC for detecting SSB / CSI-RS.

[0114] Proposal 5: A solution is required to provide a suitable configuration of the measurement gap / SMTC for detecting SSB / CSI-RS. Proposal 7: Due to NTN's measurement gap configuration (20 / 5), RAN2 cannot assume that the network always has accurate location information for the UE.

[0115] Proposal 6: Agree on Proposal 7 in R2-2010795: Due to NTN's measurement gap configuration, RAN2 cannot assume that the network always has accurate location information for the UE. Proposal 8: More discussion is needed in RAN2 before sending the LS to RAN4 to clarify the requirements for the measurement SMTC / gap configuration (16 / 6) at NTN.

[0116] Proposal 7: Agree on Proposal 8 in R2-2010795: More discussion is needed in RAN2 before sending LS to RAN4 to clarify the requirements for measurement SMTC / gap configuration at NTN.

[0117] U.S. Provisional Patent Application No. 63 / 140,578

[0118] 1. Introduction The challenges to user instrument (UE) measurements caused by differences in propagation delay between satellites remain a subject of debate. During the offline discussion

[0106] [NTN] on measurement timing configuration (SMTC) and gap based on synchronization signal (SS) / physical broadcast channel (PBCH) (Round 2), the following agreement was reached: agreement: 1. Proposal 1: NTN's SMTC and gap configurations are configured based on the timing of the primary cell (PCell). 2. Wireless access network 2 (RAN2) understands that, similar to the principle in terrestrial networks (TN), UEs are not required to detect SSB bursts outside the corresponding SMTC window configured by NTN. 3. Similar to TN, UEs should have a consistent understanding of measurement gaps to avoid unsynchronized behavior between UEs and networks, along with the network in NTN. 4. Rel-17 supports New Radio (NR) NTN, which can obtain at least one of its position, reference time, and frequency based on its Global Navigation Satellite System (GNSS) implementation. Radio Access Network 1 (RAN1) 102e.

[0119] background: During a UE handover from a serving cell to a neighboring cell, the UE needs to perform measurements to properly synchronize and connect to the neighboring cell. In some embodiments, such as when the serving cell and neighboring cell operate on different carrier frequencies, the UE cannot simultaneously transmit and receive with the serving cell and synchronize and connect with the neighboring cell. Therefore, in some radio technologies, such as 5G NR, a measurement gap is a time period provided by the network that allows the UE to perform appropriate measurements with the neighboring cell in order to synchronize and connect to it. In some embodiments, such as 5G NR, the UE performs measurements about the neighboring cell's SSB during the measurement gap. In some embodiments, the network provides the timing of the neighboring cell SSB using SMTC. In connected mode, the network provides the UE with an SMTC that defines a window of time during which the UE can perform measurements on a neighboring cell SSB. The SMTC consists of a window periodicity, offset, and window duration, and is based on the timing of the primary cell (PCell) (also referred to as the “serving cell”). The window periodicity (measurement gap) can be configured as 5, 10, 20, 40, 80, or 160 ms, and the SMTC window duration can be configured as 1, 2, 3, 4, or 5 ms. Figure 1 below (Figure 14 in this application) illustrates several SMTC / measurement gap configurations according to certain embodiments. In some embodiments, a measurement gap is configured if, based on the capabilities of the UE, the UE is unable to measure SSB for neighboring cells and cannot simultaneously monitor the serving cell. In some embodiments, the serving cell does not schedule the UE during the measurement gap. The network ensures that SSB from neighboring cells is transmitted during the measurement gap so that the UE can measure the intensity and quality of neighboring cell SSB. In some embodiments, the UE needs to generate neighboring cell measurement results at appropriate intervals to satisfy the requirements of TS 38.133, which is incorporated herein by reference in its entirety. Figure 2 (Figure 15 in this application) illustrates details of measurement gap / SMTC configurations according to some embodiments.

[0120] Exemplary problems that can be resolved by disclosure: In the low Earth orbit (LEO) NTN scenario, the propagation delay at which the nearby cell SSB reaches the UE constantly changes due to satellite movement. Therefore, the SMTC / measurement gap configuration must account for this delay variation. The delay can differ based on the relative position of the UE on the ground, as illustrated below for user equipment 1 (UE1) and user equipment 2 (UE2). The window for SSB measurements should consider all possible nearby cell SSB delays, i.e., all possible delays between UE1 and UE2. The nearby cell delay also changes over time for the UE as the satellite moves. In Figure 3 (Figure 16 in this application), the propagation delay at which the UE touches the satellite at the position of UE1 changes to the propagation delay at which the UE touches the satellite at the position of UE2 as the satellite beam moves on the ground. Due to this movement, the nearby cell SSB timing measured by the UE also drifts. Although the UE also moves, its effect is negligible compared to the satellite's speed, so the effect of UE movement is almost negligible. Figure 4 (Figure 17 in this application) illustrates variations in propagation delay in LEO NTN according to several embodiments. If the UE is unable to perform SSB measurements for neighboring cells, the UE may be unable to report neighboring cell measurement results or perform handover condition evaluation. This negatively impacts handover performance and could lead to unexpected disconnections of the UE connection. Handover is critical in LEO NTN scenarios for satellite movement. In NTN, the UE is exposed to different propagation delays between the serving cell and neighboring cells. The SMTC configuration and SSB reception window may differ for different cells (e.g., between satellite cells at different locations, as shown in Figure 4). The UE may consist of only one measurement gap, with a maximum measurement gap length of 6 ms. Thus, for neighboring cells at different or the same frequency, the configured measurement gap may not work, and the UE may not be able to acquire the SSB of the neighboring cell for radio resource management (RRM) measurements, as shown in Figure 5 (Figure 18 in this application). A basic scenario is illustrated where SAT1[LEO600] is currently providing the serving cell for the UE, and SAT2[LEO1500] is a potential target neighbor cell. In the scenario considered, SAT1 is moving away from the UE, and SAT2, which is potentially in a different orbit, is moving towards the UE. The propagation delay between SAT1 and the UE is given by dSAT1-UE(t) (i.e., a function of time t), and the delay between SAT2 and the UE is given by dSAT2-UE(t). In the transparent satellite scenario, the propagation delay also depends on the relative position of the ground NTN gateway. In this example, SAT1 is moving towards the connected NTN-GW1, and SAT2 is moving towards the connected NTN-GW2. The propagation delays between the satellite and the gateway, respectively, are dSAT1-GW1(t) and dSAT1-GW2(t). Due to satellite movement, propagation delay varies over time. Figure 19 provides a numerical example based on the estimated elevation angles between UE and SAT1 / SAT2, and between NTN-GW1 and SAT1, and NTN-GW2 and SAT2. In this example, it is assumed that the LEO satellite is orbiting at an altitude of 600 km. According to the recent RAN2 agreement listed in the introduction, the timing of the UE is based on the serving cell (SAT1 in this example). Therefore, the UE is tangent to the SSB drift from the neighboring cell (SAT2). Based on the assumed geometric arrangement of the scenarios in Figure 4 and Table 1, the propagation delay between NTN-GW1 and UE varies from 5.1 ms to 6.1 ms, and the propagation delay between NTN-GW2 and UE decreases from approximately 13.4 ms to approximately 10.6 ms. Thus, the delay difference between the two connections observed by the UE varies from 18.5 ms at T1 to 16.7 ms at T2. The maximum SMTC window duration is 5 subframes, and depending on the initial temporal position of the SSB in the SMTC window of SAT2, a statically configured window may not be able to accommodate the variation in propagation delay. Since RAN2 agreed that UEs are not required to monitor SSBs outside the configured SMTC window, measurements for neighboring cells are challenging, at least for (quasi)static SMTC configurations, with the current SMTC configuration options. Due to the delay difference, dynamically adjusting the gap configuration is essential. The SMTC window follows the dynamically determined gap configuration. The challenges are even more pronounced in the case of LEO and geostationary orbit (GEO). 38.811: See Figure 20.

[0121] 2. Discussion

[0122] 2.1. Opinions on the existing proposal (R2-2010795) First, I will present my views on existing proposals that require discussion, which are referenced in their entirety in this book. Proposal 2-1: RAN2 understands that the impact of inter-satellite latency differences on the SMTC configuration should be addressed by NTN. FFS: Is improvement of the SMTC configuration necessary at NTN? As described later in R2-2010795, the SMTC window should be improved for NTN systems because it needs to accommodate delay variations between serving and neighboring cells / satellites. "In the typical case of a TN system, the SSB burst signal generated by a neighboring cell is always detectable within the corresponding SMTC window configured via the serving cell. Outside the configured corresponding SMTC window, the UE does not need to measure the SSB burst signal. However, for NTN systems, analysis reveals that the SSB burst signal generated by a neighboring cell may be outside the corresponding SMTC window configured via the serving satellite. If the UE has the ability to capture the difference in propagation delay between the serving and neighboring satellites, even if the SSB burst signal is outside the configured corresponding SMTC window, the UE can still know when to detect the actual SSB burst signal generated by the neighboring cell. If RAN2 does not want improvements to the SMTC configuration for NTN, the UE should be allowed to search for the SSB burst signal generated by the neighboring cell even outside the configured corresponding SMTC window." Assumption: 1) Based on Proposal 6-1 Option 2: "It is up to the UE / network (NW) to obtain the measurement gap on the UE side based on its position and the candidate satellite's orbit. Since the actual timing of the SMTC window on the UE side for cells on other satellites changes over time based on the satellite's movement, the NW needs to obtain the actual timing of the measurement gap on the UE side based on the UE's position and the candidate satellite's orbit. Note: In this example, the measurement gap is maintained per satellite." 2) By agreement reached at RAN1 Meeting #103, it can be assumed that UEs always have their location information via GNSS. Exemplary Embodiment: A method for determining a measurement gap for a UE even when a 5G wireless node (gNB) does not have UE location information. 1. gNB sends the trajectory of the neighboring cell to the UE in radio resource control (RRC) signaling as part of MeasObjectNR RRC. 2. The UE can calculate the propagation delay of nearby cells / satellites based on the UE's position and the orbit of nearby satellites. 3. If the UE detects a significant round-trip delay (RTD) (> "Delta RTD" ms) between the serving and nearby satellites, it notifies the gNB via an RRC message. 4. gNB constitutes a measurement gap for each neighborhood, or extends the measurement gap based on UE feedback. 5. The UE calculates the RTD for the neighbors after a pre-configured period "Delay report periodicity" indicated by the gNB, and reports the RTD to the serving cell via an RRC message if the RTD change for the neighbors is greater than "Delta RTD Act". See Figure 21. 6. When the UE reports a neighboring delay difference threshold smaller than "Delta RTD deAct", the measurement gap is invalidated. RTD: Round-trip delay Delta RTD: Round-trip delay between a serving cell and a neighboring cell. Step 1: In some embodiments of Step 1, the transmission of the trajectory of a neighboring cell to the UE is performed in the MeasObjectNR RRC. MeasConfigNR RRC Initially, gNB constitutes only one measurement gap. mgrp (measurement gap repeating period) is the periodicity (ms) of the measurement gap repeating. Periodicities of 20, 40, 80, and 160 ms are defined in NR. `gapOffset` is the gap offset of the gap pattern. There are 160 offset values ​​in total, but not all periodicities are applicable. The offset value specifies the starting subframe within the period, so its range is from "0" to "mgrp-1". For example, if the periodicity is 40ms, the offset range is from "0" to "39". mgl (measurement gap length) is the length of the measurement gap in milliseconds (ms). Measurement gap lengths of 1.5, 3, 3.5, 4, 5.5, and 6 ms are specified in NR. mgta (Measurement Gap Timing Advance). When this is configured, the UE starts the measurement mgta (ms) before the occurrence of the gap subframe. That is, the measurement gap starts at a time that is mgta (ms) ahead of the end of the most recent subframe occurring immediately before the measurement gap. The amount of the timing advance may be 0.25 ms (FR2) or 0.5 ms (FR1). See Figure 22. Step 2: In some embodiments of step 2, the UE calculates the nearby transmission delay based on the nearby satellite orbit reported by the UE. I. If any of the reported vicinitys are outside the SMTC window of the measurement configuration (see Figure 24). Note: The satellite transmission delay calculation mechanism is still being discussed in RAN1. Step 3: In one embodiment of Step 3, the UE trigger event "Delay A1" is measured for a nearby delay delta > "Threshold X". Step 4: In one embodiment of step 4, the gNB configures an additional MeasGap via RRC Reconfiguration. See Figure 25. Note: gNB constitutes an additional gap measurement only if neighboring cell SSBs are not detected by changing mgl, mgrp, mgta, or SMTC window size / offset. Step 5: In some embodiments of step 5, the UE configures an additional gap measurement. See Figure 26. Step 6: If the UE measures a delay difference smaller than the “delay threshold X” between neighboring cells and serving cells In some embodiments of Step 6, the UE trigger event "Delay A2" is measured near the delay delta < "Delay Threshold X". Some advantages of the scheme: 1) The UE location on the network is not required. 2) The SMTC measurement window does not need to be extended beyond 5 ms (a long SMTC window degrades spectral efficiency). 3) The scheme can work at any time for nearby satellite types LEO600-LEO1500-GEO. 4) The gap is dynamically configured to improve spectral efficiency. 5) Since the gNB has delay information from nearby satellites, the gap configuration can be minimized. 6) Acquiring delay information from nearby satellites improves RACH and HO performance. 7) Provide gNB with the flexibility to choose between "gap periodic implementation complexity" and "optimal resource utilization."

[0123] Appendix: In NR, cell quality is measured using SSBs. Each SSB has two synchronization signal and physical broadcast channels with longer transmission periodicities compared to the cell reference signal (CRS). The SSB periodicity can be set within the ranges of 5, 10, 20, 40, 80, and 160 ms for each cell. However, terminals do not need to measure cell quality with the same periodicity as the SSB; an appropriate measurement periodicity can be set depending on the channel conditions. This avoids unnecessary measurements and saves terminal power. To inform terminals of the SSB periodicity and timing they must use for cell quality measurement, a new SSB-based Radio Resource Management (RRM) Measurement Time Configuration (SMTC) window has been introduced. The SMTC window periodicity may be set within the same range as the SSB (i.e., 5, 10, 20, 40, 80, and 160 ms), and the window duration may be set to 1, 2, 3, 4, or 5 ms, depending on the number of SSBs sent to the cell being measured. A UE notified of an SMTC window by a gNB detects and measures the SSB within that window and reports the measurement results to the serving base station. The RRM measurement timing configuration or SMTC based on the SS block is measurement window periodicity / duration / offset information for the UE's RRM measurement for each carrier frequency. For intra-frequency connection mode measurements, up to two measurement window periodicities may be configured. For idle mode measurements, a single SMTC is configured for each carrier frequency. For inter-frequency connection mode measurements, a single SMTC is configured for each carrier frequency. See Figure 27. Using the same RF transceiver to measure the quality of neighboring cells or other component carriers, and to send and receive data in the serving cell, can reduce implementation costs. Nevertheless, this means that data cannot be sent or received in the serving cell while other cells or component carriers of different frequencies are being measured. In LTE, UE data transmission in the serving cell is stopped during the measurement gap, giving the UE an opportunity to adjust its RF transceiver to perform measurements of neighboring cell quality or other component carriers of different frequencies. The concept of a measurement gap is used in NR. However, the measurements are performed over SSB, and the measurement gap configuration is improved compared to LTE. In LTE, the measurement gap length (MGL) is fixed, and at least one primary / secondary synchronization signal can be observed within the gap. In LTE, the primary / secondary synchronization signal is sent every 5ms. Therefore, the MGL in LTE is 6ms, with 0.5ms allowed for RF adjustments at the beginning and end of the measurement gap. The terminal detects the synchronization signal within the MGL and identifies the cell ID and reception timing. The terminal then performs measurements on the CRS. In NR, the SMTC window duration can be set to match SSB transmission. However, a fixed MGL can lead to a potential degradation of serving cell throughput. For example, if the SMTC window duration is 2ms and the MGL is 6ms, a 4ms interval is unavailable for data transmission and reception in the serving cell. The measurement gap pattern is characterized by MGRP and MGL. There are 24 gap pattern configurations defined in 38.133 to meet all needs for NR and E-UTRAN measurements. The measurement gap pattern is pre-sent in the table below (Figure 28). Configuration provided by NR RRC In the following cases, NR RRC is responsible for providing the measurement gap pattern configuration to the UE. This is done using the MeasGapConfig IE within the MeasConfig IE and transmitted via the RRC Reconfiguration message. NR RRC is responsible for the following: - Configure the UE with gapUE or gapFR1 in NR standalone operation (single carrier, with NR CA and NR-DC) or NE-DC configuration. • Configure the UE with gapFR2 in any configuration (i.e., NR standalone operation (single carrier, with NR CA and NR-DC) or EN-DC or NE-DC). The MeasGapConfig IE specifies the measurement gap configuration and controls the setup / release of the measurement gap. Details of this IE are given below (Figure 29); *gapOffset: This can be defined as the offset of the gap pattern. There are approximately 160 offset values, but not all values ​​are applicable to all periodicities. The offset value specifies the starting subframe within the period, so its range is from "0" to "mgrp-1". For example, if the periodicity is 20ms, the offset range is from "0" to "19". *Measurement gap length (mgl): This is the length of the measurement gap in ms. The measurement gap length may be 1.5, 3, 3.5, 4, 5.5, and 6 ms. *Measurement gap repetition period (mgrp): This determines the periodicity (ms) of the measurement gap repetition. This can be configured as 20, 40, 80, and 160 ms. *Measurement gap timing advance (Mgta): If this is configured, the UE starts the measurement mgta (ms) before the gap subframe occurs. That is, the measurement gap starts at a time that is mgta (ms) ahead of the end of the most recent subframe that occurs immediately before the measurement gap. The amount of the timing advance may be 0.25 ms (FR2) or 0.5 ms (FR1). See Figure 30. Handling of measurement gaps (from the perspective of Media Access Control (MAC)) During the measurement gap, on the serving cell within the corresponding frequency range (FR) of the measurement gap, the MAC entity performs the following: • Does not perform transmission of HARQ (Hybrid Automatic Repeat Request) feedback, scheduling requests (SRs), and channel status information (CSIs). • Does not report sounding reference signals (SRS). Except for Msg3, do not transmit over the Uplink (UL) Shared Channel (SCH). • Does not receive on the downlink (DL) channel. • Do not monitor the physical downlink control channel (PDCCH) unless the UE is waiting for Msg2 or Msg4 during a random access (RA) procedure. reference: The entire text is incorporated into this book by reference, 3GPP TS38.311 The entire text is incorporated into this book by reference, 3GPP TS38.821 The entire text is incorporated into this book by reference, 3GPP TS38.811 5G Wireless Performance and Management The entire document is referenced in this book by the following source: https: / / www.nttdocomo.co.jp / english / binary / pdf / corporate / technology / rd / technical_journal / bn / vol20_3 / vol20_3_009en.pdf.

Claims

1. A method performed by a terminal connected to a first cell, The orbital data of the satellite providing the second cell and the synchronization signal (SS) / physical broadcast channel (PBCH) block measurement timing configuration (SMTC) indicating the measurement period of the SSB (Synchronization Signal Block) related to the second cell are received from the network providing the first cell. Based at least on the propagation delay for the second cell calculated based on the orbital data, it is recognized that the SSB is received outside the measurement period, Sending information to the network indicating that the SSB is received outside the measurement period, A method for providing this.

2. The method according to claim 1, further comprising receiving an adjusted SMTC in response to the transmission of the information.

3. The method according to claim 1, wherein the SMTC includes at least one of the offset, periodicity, and duration of the cell measurement window.

4. The method according to claim 1, wherein the orbital data includes at least one of the position of the satellite, the velocity of the satellite, and the relative cell positions within the satellite.

5. The method according to claim 1, wherein the network comprises the first cell.

6. The method according to claim 5, wherein the propagation delay comprises a delay difference representing the difference in the propagation delay between the first cell and the second cell.

7. Receiving a measurement period modified based on the spectral efficiency of the first cell, Measuring the SSB during the modified measurement period, The method according to claim 1, further comprising:

8. The second cell is a candidate for the handover of the terminal, The terminal performs a handover evaluation process based on the SSB measured during the modified measurement period. The method according to claim 1.

9. Receiving from the network providing the first cell the orbital data of the satellite providing the second cell and the synchronization signal (SS) / physical broadcast channel (PBCH) block measurement timing configuration (SMTC) indicating the measurement period of the SSB (Synchronization Signal Block) related to the second cell, Based at least on the propagation delay for the second cell calculated based on the orbital data, it is recognized that the SSB is received outside the measurement period, Sending information to the network indicating that the SSB is received outside the measurement period, To cause a terminal connected to the first cell to perform an operation comprising the above, A non-temporary computer-readable medium containing instructions that can be executed by the aforementioned terminal.

10. The computer-readable medium according to claim 9, further comprising the operation receiving a modified SMTC in response to the transmission of the information.

11. The computer-readable medium according to claim 9, wherein the SMTC includes at least one of the offset, periodicity, and duration of the cell measurement window.

12. The computer-readable medium according to claim 9, wherein the orbital data includes at least one of the satellite's position, the satellite's velocity, and the relative cell positions within the satellite.

13. The network comprises the first cell, as described in claim 9, for the computer-readable medium.

14. The computer-readable medium according to claim 13, wherein the propagation delay comprises a delay difference representing the difference in propagation delay between the first cell and the second cell.

15. Receiving from the network providing the first cell the orbital data of the satellite providing the second cell and the synchronization signal (SS) / physical broadcast channel (PBCH) block measurement timing configuration (SMTC) indicating the measurement period of the SSB (Synchronization Signal Block) related to the second cell, Based at least on the propagation delay for the second cell calculated based on the orbital data, it is recognized that the SSB is received outside the measurement period, Sending information to the network indicating that the SSB is received outside the measurement period, A terminal comprising a controller that includes circuitry configured to perform the following actions.

16. The terminal according to claim 15, wherein the controller is further configured to receive a coordinated SMTC in response to the transmission of the information.

17. The terminal according to claim 15, wherein the SMTC includes at least one of the offset, periodicity, and duration of the cell measurement window.

18. The terminal according to claim 15, wherein the orbital data includes at least one of the satellite's position, the satellite's velocity, and the relative cell positions within the satellite.

19. The terminal according to claim 15, wherein the network comprises the first cell.

20. The terminal according to claim 19, wherein the propagation delay comprises a delay difference representing the difference in propagation delay between the first cell and the second cell.

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