Communication network

Abstract

After the one or more repeater devices have connected to the apparatus, the apparatus of the non-terrestrial radio access network assigns a signature to the one or more repeater devices, and broadcasts location information regarding a location of the one or more repeater devices and an indication of the signature of the one or more repeater devices. The user equipment detects at least one specific change with respect to a burst received by the user equipment, compares the one or more predetermined signatures to the at least one specific change, and if a predetermined signature of the one or more predetermined signatures corresponds to the at least one specific change, transmits the one or more predetermined signatures to the user equipment. A connection to a non-terrestrial radio access network is represented via a repeater device that has been assigned a predetermined signature.

Description

Technical Field

[0001] At least some example embodiments relate to communication networks, and in particular non-terrestrial networks (NTNs). Background Art

[0002] In most cellular systems, several users can be connected to one base station, as they can be assigned different time and frequency resources. In order to ensure that the signals from different users do not interfere with each other in the uplink (UL) and do not overflow in time and frequency into the resources allocated to other users, the user equipment (UE) is required to be synchronized, i.e., time and frequency are aligned with each other.

[0003] In terrestrial networks (TNs), where the frequency deviation experienced by users is typically not significant, the difference in propagation time of signals arriving at the base station when sent by different UEs can vary significantly depending on their relative locations with respect to the base station. To compensate for this, the UEs are required to perform timing advance. After the random access procedure, the gNB estimates the timing advance to be applied to each individual UE. After this point, the network can issue timing advance commands to maintain the UEs' time alignment.

[0004] However, before random access, conventional UEs do not know the size of the propagation delay, so no timing advance is applied. Therefore, random access (RA) resources are generally more robust to time and frequency impairments, and they utilize a set of predefined preamble sequences to enable more robust reception by the base station side.

[0005] In NTN (Non-Terrestrial Network), the common delays observed between UE and satellite at distances of hundreds of kilometers are much larger than those typically observed in TN. Therefore, the RA preamble and RACH procedures as from TN are not designed to support correct detection of RA attempts and proper round-trip delay estimation. In addition, for LEO (Low Earth Orbit) satellite types (at an altitude of 300-1500km), the observed very high speeds - of the order of about 7.5 km / s - result in rapid variations in delay. Therefore, delay correction cannot be managed by conventional procedures and more advanced delay estimation procedures are required; in addition, the amount of timing advance commands required to maintain such a connection will generate a huge overhead in physical layer resources.

[0006] In order to allow delay estimation before and after the random access procedure, it has been decided to use the GNSS (Global Navigation Satellite System) in conjunction with the UE. The corresponding protocol instructs the UE to determine the satellite position through the ephemeris information broadcast by the base station and estimate the delay to the UE position obtained via the GNSS. The protocol includes but is not limited to: The UE may derive one or more of the following based on its GNSS implementation: Its location o Reference time and frequency • And, based on one or more of these elements together with additional information signaled by the network (e.g., serving satellite ephemeris or timestamp), the UE can calculate timing and frequency and apply timing advance and frequency adjustment at least for UEs in RRC idle / inactive mode. NTN UEs in RRC_IDLE and RRC_INACTIVE states need to support at least UE-specific TA based on their GNSS acquired position and serving satellite ephemeris calculate. An NTN UE in RRC_CONNECTED state needs to support UE-specific TA calculation based at least on its GNSS acquired position and serving satellite ephemeris.

[0007] NTN is expected to serve remote and underserved areas and other applications. In this sense, UEs can be located in energy-constrained locations. This makes inefficient use of UE power a serious problem to be solved. In addition, there are several services, the most important of which is IoT over NTN, where several low-cost UEs can be in a given geographical area, such as a container ship, a sensor network in a jungle / island, etc.

[0008] In addition, NTN has been considered by many players as a solution for providing internet access to third countries. This means providing coverage in remote villages, for example, located in underserved areas or areas lacking infrastructure. Installing full cellular towers is too expensive. NTN solutions suffer from the inability to serve indoor users (because GNSS coverage is lacking indoors) and poor data rates for handheld devices.

[0009] Turning on the GNSS RF circuitry to frequently acquire the UE position may result in wasted power, especially considering that the UE may need several seconds to wake up from a deep sleep state before acquiring its position. For example, a GNSS warm start (where the UE has an almanac but no ephemeris) takes about 30 seconds, while a hot start (where the UE has both an almanac and ephemeris) takes 1-5 seconds.

[0010] Low-cost UEs are also affected by the fact that GNSS and cellular modems share RF chain components in several sold devices. Therefore, acquiring a GNSS position means that the UE is not available to receive / send 5G NR signals sent over the NTN. This will further increase the amount of time required for the UE to wake up to complete an operation cycle. In addition, the UE may not be able to operate GNSS and 3GPP radios at the same time. List of abbreviations 3GPP Third Generation Partnership Project 5G Fifth Generation C-Plane Control Plane DL Downlink gNB 5G Node B, next generation Node B GNSS Global Navigation Satellite System GW Gateway IoT MIB Master Information Block NCR Network Control Repeater NR New Radio NTN Non-Terrestrial Network OTA in the air OTDOA Observed Time Difference of Arrival PDP Power Delay Profile PSS Primary Synchronization Signal RA Random Access RF Radio Frequency RRC Radio Resource Control RSRP Reference Signal Received Power SI System Information SIB System Information Block SSB Synchronous Signal Block SSS Secondary synchronization signal TN Terrestrial Network UE User Equipment UL Uplink U-PlaneUser Plane Summary of the invention

[0011] At least some example embodiments are directed to eliminating UE dependence on GNSS for UE pre-compensation of time and frequency in NTNs.

[0012] According to at least some example embodiments, this is achieved by the method, apparatus and non-transitory computer-readable storage medium specified by the appended claims.

[0013] At least some example embodiments provide cost-effective solutions including indoor coverage.

[0014] According to at least some example embodiments, tracking of satellite movement and signals, high transmission power in uplink, limited indoor / jungle coverage due to lack of GNSS support, excessive use of GNSS, etc. may be avoided, thereby alleviating stringent power consumption on NTN users.

[0015] At least some example embodiments enable a new framework for NTN UEs that minimizes reliance on GNSS.

[0016] At least some example embodiments do not change the behavior of legacy UEs and UEs that decide to ignore information provided by the gNB.

[0017] According to at least some example embodiments, the overhead in the physical interface is very small.

[0018] Some example embodiments will be described hereinafter with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Flowcharts are shown illustrating Process 1 and Process 2 according to at least some example embodiments.

[0020] Figure 2 A diagram showing a NTN scenario.

[0021] Figure 3 A signaling diagram illustrating signaling according to at least some example embodiments is shown.

[0022] Figure 4 A flow chart illustrating a UE process for identifying an NTN-NCR is shown according to at least some example embodiments.

[0023] Figure 5 Diagrams illustrating different scenarios for applying at least some example embodiments are shown.

[0024] Figure 6 A diagram illustrating NTN-NCR identification is shown according to at least some example embodiments.

[0025] Figure 7 A diagram illustrating NTN-NCR identification is shown according to at least some example embodiments.

[0026] Figure 8 A schematic block diagram showing a configuration of a control unit in which example embodiments may be implemented. DETAILED DESCRIPTION

[0027] In at least some example embodiments, repeater devices such as RF repeaters that have been used in, for example, 2G, 3G, and 4G deployments to improve network coverage are utilized.

[0028] According to at least some example embodiments, the repeater device is a non-regenerative type of relay node that amplifies and retransmits transmissions it has received. According to at least some example embodiments, the repeater device is a full-duplex node.

[0029] According to at least some example embodiments, a repeater device is a terrestrial device that provides transmission repetition.

[0030] According to at least some example embodiments, a repeater device relays NTN signals in a given area, such as a village in a remote location, a village outside a terrestrial network grid, a container ship, or an area monitored by sensors on a protected jungle / forest.

[0031] Hereinafter, the repeater device is also referred to as "NTN intelligent repeater" or NTN-NCR (Network Controlled Repeater).

[0032] Reference now Figure 1 , which shows a flow chart showing process 1 and process 2 according to at least some example embodiments. Process 1 will be described below, and process 2 will be described later.

[0033] According to at least some example embodiments, process 1 is performed by a device of a non-terrestrial radio access network. According to at least some example embodiments, the device is a base station located at a satellite or gateway of the NTN, such as an eNB, gNB.

[0034] According to at least some example embodiments, process 1 is triggered when a repeater device is connected to the apparatus and / or the repeater device is configured.

[0035] After the process 1 is triggered, it proceeds to step S1101, in which a signature is assigned to the repeater device after the repeater device has been connected to the apparatus. Then, the process 1 proceeds to step S1103.

[0036] In step S1103, location information about the location of the repeater device is broadcasted along with an indication of the signature assigned to the repeater device in step S1101. Process 1 then ends.

[0037] According to at least some example embodiments, in step S1103 , polarization information about a polarization configuration associated with a repeater device is broadcast.

[0038] According to at least some example embodiments, process 1 is performed for several or more repeater devices.

[0039] According to at least some example embodiments, the signature is unique to each of the one or more repeater devices associated with the apparatus.

[0040] According to at least some example embodiments, the signature includes a pattern of downlink transmissions to be performed by the one or more relay devices, the pattern of downlink transmissions being repetitions of transmissions received by the one or more relay devices from the apparatus.

[0041] According to at least some example embodiments, the signature includes an on / off pattern for downlink transmissions for each of the one or more repeater devices.

[0042] According to at least some example embodiments, for each of the one or more repeater devices, the signature includes an on / off pattern of downlink transmissions to be performed by the one or more repeater devices, the downlink transmissions being repetitions of transmissions received by the one or more repeater devices from the device, the on / off pattern being associated with at least one of: a full time slot, a subframe, a symbol, a bandwidth portion, a subset of a bandwidth portion, or any downlink reference structure including at least one of a synchronization signal block, a primary synchronization signal, a secondary synchronization signal, or channel state information.

[0043] According to at least some example embodiments, for each of the one or more repeater devices, the signature includes a sequence of downlink transmissions to be performed by the one or more repeater devices, the downlink transmissions being repetitions of transmissions received by the one or more repeater devices from the apparatus, wherein according to the sequence, at some predefined occasions, the repetitions will be turned off.

[0044] According to at least some example embodiments, the indication of the signature includes a list of repeater devices, each repeater device being associated with its location information and a unique signature.

[0045] According to at least some example embodiments, the one or more repeater devices include a radio frequency signal repeater.

[0046] According to at least some example embodiments, one or more repeater devices include analog repeaters.

[0047] According to at least some example embodiments, one or more repeater devices are terrestrial.

[0048] According to at least some example embodiments, one or more of the repeater devices are stationary and the location information includes a single location.

[0049] According to at least some example embodiments, the one or more repeater devices are mobile, and the location information includes at least one location and a time corresponding to the at least one location.

[0050] According to at least some example embodiments, one or more repeater devices are used to provide repetition of transmissions.

[0051] According to at least some example embodiments, an apparatus of a non-terrestrial radio access network obtains the location of one or more relay devices, for example directly from the one or more relay devices, via a core network, or via a location and management function of the core network.

[0052] According to at least some example embodiments, an apparatus of a non-terrestrial radio access network determines a location of one or more repeater devices based on a positioning method.

[0053] According to at least some example embodiments, an apparatus of a non-terrestrial radio access network determines a location of one or more repeater devices based on an Observed Time Difference of Arrival (OTDOA).

[0054] According to at least some example embodiments, an apparatus of a non-terrestrial radio access network receives an update of a location from one or more repeater devices.

[0055] According to at least some example embodiments, an apparatus of a non-terrestrial radio access network configures the one or more repeater devices when the one or more repeater devices are being connected to the apparatus.

[0056] According to at least some example embodiments, an apparatus of a non-terrestrial radio access network configures a signature for the one or more repeater devices when the one or more repeater devices are being connected to the apparatus.

[0057] According to at least some example embodiments, when the one or more repeater devices are being connected to the apparatus, the apparatus of the non-terrestrial radio access network configures the one or more repeater devices by setting a transmission power for repetitions of transmissions to the apparatus and one or more user devices to be performed by the one or more repeater devices, the transmissions being received by the one or more repeater devices.

[0058] According to at least some example embodiments, in step S1101 of process 1, after the NTN smart repeater is connected and configured to the NTN base station (e.g., gNB), the NTN base station obtains the location of the NTN smart repeater and assigns a signature (hereinafter also referred to as a "repeater signature") to the NTN smart repeater. The repeater signature is unique for each NTN smart repeater associated with the NTN base station.

[0059] According to at least some example embodiments, the signature is a repeated on / off pattern (of gNB transmissions) from a full time slot or subframe or from a specific resource. According to at least some example embodiments, the NTN smart repeater has a repeated "puncturing pattern" (hereinafter also referred to as "puncturing pattern") on a synchronization block (SSB), i.e., in some predefined occasions, the repetition of the synchronization block will be turned off.

[0060] According to at least some example embodiments, in step S1103 of process 1, the base station includes location information of (multiple) NTN smart repeaters and an indication of the signature in a broadcast SI message.

[0061] Then, a clever UE implementation can use the information from the NTN smart repeater that is repeated and broadcast by the base station so that the UE can identify the presence of the NTN smart repeater and use this information to refine positioning (e.g., by assuming the location of the NTN smart repeater). The specific details of how the UE identifies the presence of the NTN smart repeater based on the smart repeater signature will be described later.

[0062] Note that process 1 does not deactivate the NTN smart repeater or any other function thereof for legacy UEs that do not know the meaning of the broadcast information, since the NTN smart repeater is not visible to the UE in principle. However, legacy UEs still have to rely on GNSS to obtain pre-compensation parameters. The set of UE actions and UE implementation for identifying the signature will be described later.

[0063] Figure 2 A diagram illustrating an NTN scenario addressed by at least some example embodiments is shown, and Figure 3 A signaling diagram illustrating signaling according to at least some example embodiments is shown.

[0064] As a starting point, UE( Figure 2 The UE shown in Figure 3 The UE(s) 30 shown in FIG. 1 are unaware of the presence of the NTN smart repeater (in Figure 2 is indicated as a "repeater" in Figure 3 Indicated as "Repeater 10" in FIG. Figure 2 As shown, at a base station located at a satellite or a gateway (GW) (according to Figure 3 There is ongoing signaling between the base station 20) and the NTN smart repeater. However, the NTN smart repeater cannot modify the content of the encapsulated message (e.g., on the UE control plane and user plane) that it repeats (i.e., amplifies and forwards).

[0065] exist Figure 3 In step S301, the repeater 10 sends a connection request to the base station 20, and in step S302, the repeater 10 is configured. In other words, in steps S301 and S302, the repeater 10 establishes a connection with the base station 20. For example, via Figure 2 The SmRe (Smart Receiver) control plane shown establishes the connection.

[0066] After the repeater 10 is configured, the repeater 10 is already able to repeat and amplify UL and DL transmissions between the base station 20 and (multiple) UEs 30 (step S303), as a TN repeater would do. At this point, UL transmissions are only available to UEs in connected mode, which are able to gain access by acquiring positioning information from other sources (e.g., GNSS) and are unaware of the presence of the NTN smart repeater 10.

[0067] For example, the base station 20 obtains the location of the NTN intelligent repeater 10 by issuing a positioning request (step S304) and receiving a positioning parameter report (step S305), for example, by using Figure 2 The signaling of the SmRe control plane is shown.

[0068] The method used to obtain the location report may vary and use one or more of the following: · The Location and Management Function (LMF) is responsible for obtaining and managing the NTN intelligent repeater locations. Alternatively, the location is stored locally in the eNB / gNB which is connected to a satellite providing coverage in the area of ​​the NTN smart repeater. The positioning parameter report includes the position of the NTN smart repeater, which can be obtained by the NTN smart repeater through different components (GNSS, external sources, hard coding, etc.). • Positioning parameter reports contain measurements reported as converted into positions by base stations (eg, for some network-based positioning methods).

[0069] For example, the NTN smart repeater indicates to the network that it is stationary (e.g. if it is located in a fixed position in a village). Therefore, the position is exchanged only once and not when the next satellite provides coverage in the area. If the NTN smart repeater is moving (e.g. if it is installed on a ship), the NTN smart repeater has to trigger a location update to the network, which will then have to update the broadcasted SI.

[0070] In step S306, the base station 20, for example, Figure 2 The SmRe control plane is shown assigning a repetition signature to the NTN smart repeater 10 .

[0071] According to at least some example embodiments, a repetition signature is a pattern of DL transmissions (or repetitions) performed at the NTN smart repeater 10. According to at least some example embodiments, a signature is an "on / off" pattern of the repeater 10.

[0072] According to at least some example embodiments, based on the signature, one SSB index or a subset of SSB indices of a cell is uniquely associated with the NTN smart repeater 10. No other NTN smart repeater can repeat that SSB index / these SSB indices, nor can the NTN smart repeater 10 repeat other SSBs.

[0073] According to at least some example embodiments, the signature is a puncturing pattern over subframes. For example, every second subframe is blanked (not repeated) at the NTN smart repeater 10. Alternatively, the puncturing pattern provides a formula for indicating which subframes are not repeated.

[0074] According to at least some example embodiments, the signature is a puncture pattern on the PSS resource and the SSS resource. For example, similar to the above, the signature is a pattern indicating at what occasions the PSS resource and the SSS resource are repeated or not repeated.

[0075] According to at least some example embodiments, the signature is a puncturing pattern on the SSB (SIB). For example, a satellite will broadcast SSBs with one period, while the NTN smart repeater 10 broadcasts with a different, longer period, i.e., it does not repeat all SSBs from the satellite.

[0076] According to at least some example embodiments, based on the signature, one bandwidth portion or a subset of bandwidth portions is repeated by the NTN smart repeater 10, while other bandwidth portions or subsets of bandwidth portions are not repeated. According to at least some example embodiments, this is performed by the repeater 10 statically or dynamically over time based on the signature assigned by the base station 20.

[0077] Then, as shown in step S307, DL transmissions in the case where the NTN smart repeater 10 is "on" (the puncturing mode is indicated as active) are repeated, whereas as shown in step S308, DL transmissions in the case where the NTN smart repeater 10 is "off" are not repeated, and are available to the UE 30 only if the UE 30 is able to listen to signals sent directly from the base station 20 via the satellite.

[0078] Note that uplink transmissions of a UE 30 in connected mode are carried by the relay 10 as normal (eg amplified and forwarded), ie no signature (puncturing pattern) is applied.

[0079] In step S309, the base station 20 sends an SI (system information) update indication to inform the UE 30 that it wishes to update the SI.

[0080] In the next modification window, the SI is updated (S310). According to at least some example embodiments, the base station 20 includes the location and puncturing pattern of the NTN intelligent repeater 10 in the new version of the SI.

[0081] According to at least some example embodiments, the information is included in the NTN SI, a new SI (eg, the NTN smart repeater SI), or any other SI (eg, for applications outside the NTN).

[0082] According to at least some example embodiments, the information (parameters) includes a list of NTN smart repeaters, each NTN smart repeater being associated with a different NTN smart repeater signature.

[0083] On the UE side, after the UE receives the SI transmission, the UE is aware of the presence of the NTN smart repeater. At this point, a smart UE implementation can use this information to gather more (or refined) information about its location. It allows indoor UEs one more chance to gain connectivity, while energy-constrained UEs can use this information to decide on a more conservative / thrifty use of GNSS.

[0084] According to at least some example embodiments, a new framework for NTN UEs with minimized reliance on GNSS is implemented. Furthermore, the above solution does not change the behavior of legacy UEs and UEs that decide to ignore the information provided by the gNB (base station). Furthermore, the overhead in the physical interface is very small.

[0085] Now refer to it again Figure 1 and process 2 performed by a user equipment (UE). For example, process 2 is initiated when the UE is turned on or a specific application of the UE is started.

[0086] In step S1201, at least one specific change in a burst received by a user equipment is detected.Then, process 2 proceeds to step S1203.

[0087] In S1203, one or more predetermined features are compared with at least one specific change. Then, process 2 proceeds to step S1205.

[0088] In S1205 , it is determined whether a predetermined signature among the one or more predetermined signatures corresponds to at least one specific change.

[0089] In the case that a predetermined signature in the one or more predetermined signatures corresponds to at least one specific variant (yes in S1205), process 2 proceeds to S1207, where a connection to a non-terrestrial radio access network via a repeater device to which the predetermined signature has been assigned is identified. Then, process 2 ends.

[0090] If no match is found in S1205 (No in S1205), process 2 ends.

[0091] According to at least some example embodiments, the at least one specific change includes at least one of: a power change, a power delay profile change, and a polarization change.

[0092] According to at least some example embodiments, in the case where the specific change is a burst power change, in S1201 , a predetermined signature is detected based on a burst received power level change.

[0093] According to at least some example embodiments, in the case where the specific change is a power delay profile change, in S1201 , a predetermined signature is detected by associating a delay difference between bursts with one or more predetermined signatures.

[0094] According to at least some example embodiments, in a case where the specific change is a polarization change, in S1201 , a predetermined signature is detected based on the polarization of the burst.

[0095] According to at least some example embodiments, a burst is associated with at least one of: a full time slot, a subframe, a symbol, a bandwidth portion, a subset of a bandwidth portion, or any downlink reference structure including at least one of a synchronization signal block, a primary synchronization signal, a secondary synchronization signal, or channel state information.

[0096] According to at least some example embodiments, each of the one or more predetermined signatures includes a pattern of downlink transmissions to be performed by a repeater device that has been assigned the predetermined signature, the downlink transmissions being repetitions of transmissions received by the repeater device from an apparatus of the non-terrestrial radio access network.

[0097] According to at least some example embodiments, the predetermined signature includes an on / off pattern of downlink transmissions.

[0098] According to at least some example embodiments, the on / off mode is associated with at least one of: a full time slot, a subframe, a symbol, a bandwidth portion, a subset of a bandwidth portion, or any downlink reference structure including at least one of a synchronization signal block, a primary synchronization signal, a secondary synchronization signal, or channel state information.

[0099] According to at least some example embodiments, each of the one or more predetermined signatures comprises a sequence of downlink transmissions to be performed by a repeater device to which the predetermined signature has been assigned, the downlink transmissions being repetitions of transmissions received by the repeater device from an apparatus of the non-terrestrial radio access network, wherein according to the sequence, in some predefined occasions, the repetitions will be turned off.

[0100] A UE implemented using the process of process 2 can use the information of the specific puncturing pattern of the SSB burst and the information of the GNSS coordinates of the NTN-NCR as described above to obtain / refine its positioning solution by identifying the presence of the NTN-NCR. In addition, the solution does not deactivate the NTN-NCR or any other function thereof for legacy UEs that do not know the meaning of the broadcast parameters, because in principle the NTN-NCR is not visible to the UE. However, legacy UEs still have to rely on GNSS to obtain pre-compensation parameters. At least some example embodiments focus on NR implementations, but the process will also be valid for LTE systems, where LTE synchronization signal blocks are repeated in a puncturing pattern at the NTN-NCR.

[0101] Figure 4 A UE procedure for identifying a NTN-NCR is shown according to at least some example embodiments.

[0102] In step (1), it is assumed that the UE is in RRC idle or inactive mode when entering this UE procedure, and the UE will have to know its GNSS position before attempting to establish a connection to the gNB. Thus, if an idle UE can obtain GNSS information from the NTN-NCR, it can save some power since it does not have to track its own position and can keep its GNSS receiver turned off, or alternatively, the UE may not even utilize a GNSS receiver.

[0103] In step (2), the UE will wait for the next NTN SSB burst.

[0104] In step (3), the UE decodes the SIB (or similar message) to determine whether it contains some of the following information, as described above: -NCR SSB perforation mode; - NCR GNSS coordinates; -NCR polarization changes.

[0105] Note that at this point the UE knows that there is at least one NTN-NCR in the coverage area of ​​the cell, but since NTN cells are large (50km diameter or more), the UE will not know if it is close enough to the NTN-NCR to communicate via it. If the UE knew its own location, the UE could compare to the broadcasted NTN-NCR GNSS coordinates, but at least some example embodiments avoid this kilometer consumption step.

[0106] In step (4), the UE will identify the presence of the NTN-NCR using one or more of the following techniques, which will be described in more detail later: -SSB power change; -SSB PDP changes; -SSB polarization change.

[0107] In step (5), the UE will monitor the SSB pattern and utilize one or more of the techniques from step (4) to determine whether it is connected via the NTN-NCR.

[0108] If the UE determines that it is connected via NTN-NCR (yes in step (5)), the process proceeds to step (6).

[0109] If the UE determines that it is not connected via NTN-NCR (No in step (5)), the process proceeds to step (7).

[0110] In step (6), the UE determines whether it has received the GNSS coordinates of the identified NTN-NCR.

[0111] If the GNSS coordinates of NTN-NCR are known (yes in step (6)), the process proceeds to step (8).

[0112] If the GNSS coordinates of NTN-NCR are unknown (No in step (6)), the process proceeds to step (7).

[0113] In step (7), if the NTN-NCR is not identified or the GNSS coordinates of the identified NTN-NCR are not received, then the UE will have to rely on the traditional NTN connection process and its own GNSS coordinates.

[0114] In step (8), the UE has identified the NTN-NCR and its GNSS coordinates, and can now perform the NTN connection procedure via the NTN-NCR using the GNSS coordinates of the NTN-NCR.

[0115] According to at least some example embodiments, the NTN UE may be able to identify the presence of the NTN-NCR by one or more of the following methods: - Linking a specific known puncturing pattern to the power variations of the received SSB bursts; - Linking a specific known puncturing pattern to the PDP changes of the received SSB bursts; -Links a specific known puncturing pattern to the polarization changes of the received SSB burst.

[0116] These three techniques for detecting the presence of NTN-NCR are described in more detail below. The nuances of the use of these techniques depend on the characteristics of the scenario. Consider also Figure 5 Three possible scenarios are shown in FIG.

[0117] exist Figure 5 In the first scenario shown, UE#1 is located in a valley with no NTN-NCR coverage and will only receive NTN SSB from the satellite link (this is considered legacy operation).

[0118] In the second scenario, UE#2 is outside a mountain village covered by NTN-NCR and will be able to receive NTN SSBs from both the satellite link and the NTN-NCR link.

[0119] In the third scenario, UE#3 is inside a building in a mountain village, which is covered by NTN-NCR and will only be able to receive NTN SSBs from the NTN-NCR link. Detection of SSB puncture pattern using power level variation

[0120] For UEs close to an NTN-NCR, the power level of the NTN SSB repeated by the NTN-NCR will be higher, so the change in the received power level of the SSB signal can be used to detect the puncturing pattern and identify the presence of a specific NTN-NCR. Figure 6 , where UE#2 and UE#3 will detect the NTN-NCR and rely on the GNSS coordinates of the NTN-NCR. In this way, UE#2 and UE#3 will be able to connect via the NTN even if it is outside of GNSS coverage or if it is not implemented with a GNSS receiver and thus does not know its own location. Detection of SSB puncture pattern using PDP variation

[0121] Due to the increased distance of the NTN-NCR link, the PDPs of the NTN SSBs repeated by the NTN-NCR will be slightly delayed compared to those received directly from the satellite, as shown in Figure 7 This detection method requires that the UE can receive both the NTN satellite link and the NTN-NCR link, and is therefore only valid for use case #2 (second scenario).

[0122] The puncturing pattern is detected by associating those delay differences with the puncturing pattern, as shown in Table 1, for the second use case (second scenario), where rt is the reference time of the SSB received from the satellite. Table 1:

[0123] If the UE is very close to the NCR, the delay difference between the SSB received from the satellite and the NCR can of course be very small. Only UEs with very high sampling rates will be able to use this technique to detect the presence of the NCR, other UEs will have to rely on one or both of the other techniques. Detection of SSB punching patterns using polarization changes

[0124] Assuming that the satellite and NTN-NCR use different polarizations, the polarization of the received NTN SSB can also be used to detect the NTN-NCR. Thus, if the satellite uses circular polarization, the NTN-NCR can be configured for linear polarization and vice versa.

[0125] For three different use cases (scenarios), the puncturing pattern is detected by correlating those polarization differences with the puncturing pattern as shown in Table 2. Use cases #1 and #3 (first and third scenarios) require that the polarization information of the satellite and / or NTN-NCR is included in the MIB / SIB. Table 2:

[0126] Reference now Figure 8, which shows a simplified block diagram of a control unit 40 and a control unit 80 suitable for practicing at least some example embodiments. According to an implementation example, Figure 1 The process 1 is implemented by the control unit 40, and Figure 1 Process 2 is implemented by the control unit 80.

[0127] Control unit 40 includes processing resources (eg, processing circuitry) 41 , memory resources (eg, memory circuitry) 42 , and interfaces (eg, interface circuitry) 43 coupled via a wired or wireless connection 44 .

[0128] The control unit 80 includes processing resources (eg, processing circuitry) 81 , memory resources (eg, memory circuitry) 82 , and an interface (eg, interface circuitry) 83 coupled via a wired or wireless connection 84 .

[0129] According to an example implementation, memory resources 42 and memory resources 82 are of any type suitable for the local technical environment and are implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and removable memory. As non-limiting examples, processing resources 41 and processing resources 81 are of any type suitable for the local technical environment and include one or more of a general-purpose computer, a special-purpose computer, a microprocessor, a digital signal processor (DSP), and a processor based on a multi-core processor architecture.

[0130] According to an implementation example, memory resource 42 and memory resource 82 include one or more non-transitory computer-readable storage media storing one or more programs that, when executed by processing resource 41, processing resource 81, enable control unit 40, 80 to act as a base station of a non-terrestrial access network as described above.

[0131] Typically, a mobile device may be a user equipment (UE) such as a cellular phone, a smart phone, a laptop, a handheld device, a tablet, a vehicle, etc. A mobile device may also be a module, a modem on a module, a system in a package, or a system on a chip that can be connected to or inserted into a user device. A user device may be a fixed shape, or it may be used in different form factors.

[0132] Furthermore, as used in this application, the term "circuitry" refers to one or more or all of the following: (a) Hardware circuit implementation only (such as implementation in analog and / or digital circuitry only) as well as (b) to a combination of circuitry and software (and / or firmware), as applicable: (i) to a combination of processor(s) or (ii) portions of processor / software (including digital signal processor(s), software and memory(s) which work together to enable the device (such as a mobile phone or server) to perform various functions) and (c) to an electrical circuit such as a microprocessor(s) or a portion of a microprocessor(s), It requires software or firmware for operation, even if the software or firmware is not physically present.

[0133] This definition of "circuitry" applies to all uses of this term in this application, including in any claims. As another example, as used in this application, the term "circuitry" would also cover an implementation of only a processor (or multiple processors) or a portion of a processor and its (or their) accompanying software and / or firmware. The term "circuitry" would also cover, for example and if applicable to a particular claim element, a baseband integrated circuit or an application processor integrated circuit for a mobile phone or a similar integrated circuit in a server, cellular network device, or other network device.

[0134] According to at least some example embodiments, there is provided an apparatus of a non-terrestrial radio access network, the apparatus comprising: means for assigning a signature to one or more repeater devices after the one or more repeater devices have been connected to the apparatus; and • Means for broadcasting location information regarding the location of one or more repeater devices and an indication of a signature of the one or more repeater devices.

[0135] According to at least some example embodiments, there is provided a user equipment comprising: means for detecting at least one specific change with respect to a burst received by a user equipment; means for comparing one or more predetermined characteristics to at least one specific variation; as well as • Means for identifying, in case a predetermined signature of the one or more predetermined signatures corresponds to at least one specific change, a connection to a non-terrestrial wireless access network via a repeater device to which the predetermined signature has been assigned.

[0136] It should be understood that the above description is illustrative and should not be interpreted as limiting the scope of protection. Various modifications and applications may occur to those skilled in the art without departing from the true spirit and scope defined by the appended claims.

Claims

1. A method for use by an apparatus of a non-terrestrial radio access network, the method comprising: assigning a signature to one or more repeater devices after the one or more repeater devices have connected to the apparatus; as well as Location information regarding the location of the one or more repeater devices and an indication of the signature of the one or more repeater devices are broadcasted. 2 . The method of claim 2 , wherein the signature is unique to each of the one or more repeater devices associated with the apparatus.

3. A method according to claim 1 or 2, wherein the signature includes a pattern of downlink transmissions to be performed by the one or more repeater devices, the downlink transmissions being repetitions of transmissions received by the one or more repeater devices from the apparatus. 4 . The method according to claim 1 , wherein the signature comprises an on / off pattern of downlink transmissions for each of the one or more repeater devices.

5. A method according to any one of claims 1 to 4, wherein for each of the one or more repeater devices, the signature includes an on / off pattern of downlink transmissions to be performed by the one or more repeater devices, the downlink transmissions being repetitions of transmissions received by the one or more repeater devices from the device, and the on / off pattern is associated with at least one of: a full time slot, a subframe, a symbol, a bandwidth portion, a subset of a bandwidth portion, or any downlink reference structure including at least one of a synchronization signal block, a primary synchronization signal, a secondary synchronization signal, or channel state information.

6. A method according to any one of claims 1 to 5, wherein for each of the one or more repeater devices, the signature comprises a sequence of downlink transmissions to be performed by the one or more repeater devices, the downlink transmissions being repetitions of transmissions received by the one or more repeater devices from the apparatus, wherein according to the sequence, the repetitions are turned off in some predefined occasions.

7. The method according to any one of claims 1 to 6, wherein the indication comprises a list of the repeater devices, each of the repeater devices being associated with its location information and a unique signature.

8. The method according to any one of claims 1 to 7, wherein at least one of the following applies: The one or more repeater devices include a radio frequency signal repeater; The one or more repeater devices include an analog repeater; The one or more repeater devices are terrestrial; The one or more repeater devices are stationary and the location information comprises a single location; The one or more repeater devices are mobile, and the location information includes at least one location and a time corresponding to the at least one location; The one or more repeater devices are used to provide repetition of transmissions.

9. The method according to any one of claims 1 to 8, further comprising at least one of the following: obtaining the locations of the one or more repeater devices; obtaining the locations of the one or more repeater devices directly from the one or more repeater devices; obtaining, via a core network, the locations of the one or more repeater devices; Acquiring the location of the one or more relay devices via a location and management function of a core network; determining the location of the one or more repeater devices based on a positioning method; determining the location of the one or more repeater devices based on an observed time difference of arrival (OTDOA); receiving an update of the location from the one or more repeater devices; configuring the one or more repeater devices when the one or more repeater devices are connected to the apparatus; configuring the signature for the one or more repeater devices when the one or more repeater devices are connected to the apparatus; The one or more repeater devices are configured by setting a transmission power for repetitions of transmissions to the device and one or more user devices to be performed by the one or more repeater devices when the one or more repeater devices are being connected to the device, the transmissions being received by the one or more repeater devices.

10. The method according to any one of claims 1 to 9, further comprising: Polarization information regarding a polarization configuration associated with the one or more repeater devices is broadcasted.

11. A method for use by a user device, the method comprising: detecting at least one specific change with respect to a burst received by the user equipment; comparing one or more predetermined signatures to the at least one specific change; as well as In case a predetermined signature of the one or more predetermined signatures corresponds to the at least one specific change, a connection to a non-terrestrial radio access network via a repeater device to which the predetermined signature has been assigned is identified.

12. The method of claim 11, wherein the at least one specific change comprises at least one of: a power change, a power delay profile change, and a polarization change.

13. The method according to claim 12, comprising: In case the specific change is the power change of the burst, detecting the predetermined signature based on a change in the received power level of the burst; in case the specific change is a change in the power delay profile, detecting the predetermined signature by correlating the delay difference between the bursts with the one or more predetermined features; as well as In case the specific change is the polarization change, the predetermined signature is detected based on the polarization of the burst.

14. A method according to any one of claims 11 to 13, wherein the burst is associated with at least one of: a full time slot, a subframe, a symbol, a bandwidth part, a subset of a bandwidth part, or any downlink reference structure including at least one of a synchronization signal block, a primary synchronization signal, a secondary synchronization signal, or channel state information.

15. The method according to any one of claims 11 to 14, wherein at least one of the following applies: each of the one or more predetermined signatures comprising a pattern of downlink transmissions to be performed by the repeater device to which the predetermined signature has been assigned, the downlink transmissions being repetitions of transmissions received by the repeater device from apparatus of the non-terrestrial radio access network; The predetermined signature includes an on / off mode of the downlink transmission; The on / off pattern is associated with at least one of: a full time slot, a subframe, a symbol, a bandwidth part, a subset of a bandwidth part, or any downlink reference structure including at least one of a synchronization signal block, a primary synchronization signal, a secondary synchronization signal, or channel state information; Each of the one or more predetermined signatures comprises a sequence of downlink transmissions to be performed by the repeater device to which the predetermined signature has been assigned, the downlink transmissions being repetitions of transmissions received by the repeater device from an apparatus of the non-terrestrial radio access network, wherein according to the sequence, the repetitions will be switched off in some predefined occasions.

16. A non-transitory computer-readable storage medium storing a program, which, when executed by a computer, causes the computer to at least perform: assigning a signature to the one or more repeater devices after the one or more repeater devices have connected to the apparatus of the non-terrestrial radio access network; and Location information regarding the location of the one or more repeater devices and an indication of the signature of the one or more repeater devices are broadcasted.

17. A non-transitory computer-readable storage medium storing a program, which, when executed by a computer, causes the computer to at least perform: detecting at least one specific change with respect to a burst received by a user equipment; comparing one or more predetermined signatures to the at least one specific change; and In case a predetermined signature of the one or more predetermined signatures corresponds to the at least one specific change, a connection to a non-terrestrial radio access network via a repeater device to which the predetermined signature has been assigned is identified.

18. An apparatus of a non-terrestrial radio access network, the apparatus comprising at least one processor and at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processor, cause the apparatus to at least: assigning a signature to one or more repeater devices after the one or more repeater devices have connected to the apparatus; and Location information regarding the location of the one or more repeater devices and an indication of the signature of the one or more repeater devices are broadcasted.

19. The apparatus of claim 18, wherein the signature is unique to each of the one or more repeater devices associated with the apparatus.

20. The apparatus of claim 18 or 19, wherein the signature comprises a pattern of downlink transmissions to be performed by the one or more repeater devices as repetitions of transmissions received by the one or more repeater devices from the apparatus.

21. The apparatus of any one of claims 18 to 20, wherein the signature comprises an on / off pattern of downlink transmissions for each of the one or more relay devices.

22. An apparatus according to any one of claims 18 to 21, wherein for each of the one or more repeater devices, the signature includes an on / off pattern of downlink transmissions to be performed by the one or more repeater devices, the downlink transmissions being repetitions of transmissions received by the one or more repeater devices from the apparatus, the on / off pattern being associated with at least one of: a full time slot, a subframe, a symbol, a bandwidth portion, a subset of a bandwidth portion, or any downlink reference structure including at least one of a synchronization signal block, a primary synchronization signal, a secondary synchronization signal, or channel state information.

23. An apparatus according to any one of claims 18 to 22, wherein for each of the one or more repeater devices, the signature comprises a sequence of downlink transmissions to be performed by the one or more repeater devices, the downlink transmissions being repetitions of transmissions received by the one or more repeater devices from the apparatus, wherein according to the sequence, the repetitions are turned off in some predefined occasions.

24. An apparatus according to any one of claims 18 to 23, wherein the indication comprises a list of the repeater devices, each of the repeater devices being associated with its location information and a unique signature.

25. The device according to any one of claims 18 to 24, wherein at least one of the following applies: The one or more repeater devices include a radio frequency signal repeater; The one or more repeater devices include an analog repeater; The one or more repeater devices are terrestrial; The one or more repeater devices are stationary and the location information comprises a single location; The one or more repeater devices are mobile, and the location information includes at least one location and a time corresponding to the at least one location; The one or more repeater devices are used to provide repetition of transmissions.

26. The apparatus according to any one of claims 18 to 25, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, cause the apparatus to further perform at least one of the following: obtaining the locations of the one or more repeater devices; obtaining the locations of the one or more repeater devices directly from the one or more repeater devices; obtaining, via a core network, the locations of the one or more repeater devices; Acquiring the location of the one or more relay devices via a location and management function of a core network; determining the location of the one or more repeater devices based on a positioning method; determining the location of the one or more repeater devices based on an observed time difference of arrival (OTDOA); receiving an update of the location from the one or more repeater devices; configuring the one or more repeater devices when the one or more repeater devices are connected to the apparatus; configuring the signature for the one or more repeater devices when the one or more repeater devices are connected to the apparatus; The one or more repeater devices are configured by setting a transmission power for repetitions of transmissions to the device and one or more user devices to be performed by the one or more repeater devices when the one or more repeater devices are being connected to the device, the transmissions being received by the one or more repeater devices.

27. The apparatus according to any one of claims 18 to 26, wherein the at least one memory and the computer program code are configured to, with the at least one processor, further cause the apparatus to: Polarization information regarding a polarization configuration associated with the one or more repeater devices is broadcasted.

28. A user equipment comprising at least one processor and at least one memory comprising computer program code, the at least one memory and the computer program code being configured to, together with the at least one processor, cause the user equipment to at least: detecting at least one specific change with respect to a burst received by the user equipment; comparing one or more predetermined signatures to the at least one specific change; and In case a predetermined signature of the one or more predetermined signatures corresponds to the at least one specific change, a connection to a non-terrestrial radio access network via a repeater device to which the predetermined signature has been assigned is identified.

29. The user equipment according to claim 28, wherein the at least one specific change comprises at least one of: a power change, a power delay profile change, and a polarization change.

30. The user equipment of claim 29, wherein the at least one memory and the computer program code are configured to, together with the at least one processor, further cause the user equipment to: In case the specific change is the power change of the burst, detecting the predetermined signature based on a change in the received power level of the burst; in case the specific change is a change in the power delay profile, detecting the predetermined signature by correlating the delay difference between the bursts with the one or more predetermined features; as well as In case the specific change is the polarization change, the predetermined signature is detected based on the polarization of the burst.

31. A user equipment according to any one of claims 28 to 30, wherein the burst is associated with at least one of: a full time slot, a subframe, a symbol, a bandwidth part, a subset of a bandwidth part, or any downlink reference structure including at least one of a synchronization signal block, a primary synchronization signal, a secondary synchronization signal, or channel state information.

32. A user equipment according to any one of claims 28 to 31, wherein at least one of the following applies: each of the one or more predetermined signatures comprising a pattern of downlink transmissions to be performed by the repeater device to which the predetermined signature has been assigned, the downlink transmissions being repetitions of transmissions received by the repeater device from apparatus of the non-terrestrial radio access network; The predetermined signature includes an on / off mode of the downlink transmission; The on / off pattern is associated with at least one of: a full time slot, a subframe, a symbol, a bandwidth part, a subset of a bandwidth part, or any downlink reference structure including at least one of a synchronization signal block, a primary synchronization signal, a secondary synchronization signal, or channel state information; Each of the one or more predetermined signatures comprises a sequence of downlink transmissions to be performed by the repeater device to which the predetermined signature has been assigned, the downlink transmissions being repetitions of transmissions received by the repeater device from an apparatus of the non-terrestrial radio access network, wherein according to the sequence, the repetitions will be switched off in some predefined occasions.

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