Methods and devices enhancing the public warning system notification in non-terrestrial network cells

Abstract

Alert-related methods and devices save power used by user equipments (UEs) in a non-terrestrial network (NTN) cell for processing detailed alert information. A method (900) performed by a UE (102), receiving services via an NTN cell (124) includes receiving (944) a first message including a first public warning system (PWS) indication and coarse alert area information indicating a first PWS area within the NTN cell. The UE then determines the UE is in the first PWS area based on a UE's current position and the coarse alert area information. The UE then selectively acquires (956) a second message including first alert details related to the first PWS indication when the UE is in the first PWS area. The first PWS area (534) geographically covers a first alert area (430) associated with the first PWS indication.

Description

Attorney Docket No.: 0683-121 -WOMETHODS AND DEVICES ENHANCING THE PUBLIC WARNING SYSTEM NOTIFICATION IN NON-TERRESTRIAL NETWORK CELLSFIELD OF THE DISCLOSURE

[0001] This document generally describes methods and devices operating in wireless communication systems such as (but not limited to) the ones described in 5G standard documents, known as 3GPP communication systems. More specifically, the techniques embodied in various methods and devices reduce, to a relevant subset, the number of user equipments (UEs) acquiring a public warning system (PWS) alert message from a non-terrestrial network (NTN) cell.BACKGROUND

[0002] This background description is provided for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.

[0003] A wireless communication system includes network entities (such as, a base station (BS), a core network (CN) device, etc.) enabling communication for a mobile communication device (referred to as a user equipment (UE)). Each BS covers one or more cells to provide services to UEs located in cell coverage area. Conventional wireless communication systems and network selection techniques are mostly terrestrial networks. However, the 3rdGeneration Partnership Project (3GPP) organization has extended the use of non-terrestrial networks (NTNs) to 3GPP communication systems using 5G new radio (NR) technologies and Long-Term-Evolution (LTE) technologies tailored for the Narrowband Internet-of-Thing (NB-loT) or the enhanced Machine Type Communication (eMTC). An NTN refers to a network, or segment of networks, using radio frequency (RF) resources on board an NTN node such as spaceborne or airborne vehicles. The term “airborne vehicles” covers unmanned aircraft systems (UAS), High-Attorney Docket No.: 0683-121 -WOAltitude Platform Systems (HAPS), balloons, dirigibles, winged vehicles such as airplane or drones, etc. The term “spaceborne vehicles” covers Geostationary Earth Orbit (GEO) satellites (sometimes also referred to as geosynchronous orbit (GSO) satellites), Low Earth Orbit (LEO) satellites, Medium Earth Orbit (MEO) satellites, Highly Elliptical Orbit (HEO) satellites, etc. The NTN nodes may form constellations. For simplicity, the discussion below refers to all such apparatuses as satellites or NTN nodes.

[0004] A GSO satellite can communicate with one or several sat-gateways deployed over a satellite targeted coverage area (e.g. a region or even a continent). A non-GSO satellite at different times can communicate with one or several serving satellite gateways (sat-gateways). A sat-gateway is land-based equipment intermediating communication between terrestrial NEs and the satellite via a feeder link. The NTN is designed to provide service and feeder link communications between successive serving sat-gateways, with sufficient overlap time to proceed with mobility anchoring and hand-over.

[0005] A satellite may provide a transparent or a regenerative (with on board processing) payload and, typically, generates several beams for a given service area (NTN cell) bounded by the field of view. The footprints of the beams have an elliptic shape on a flat surface and depend on the on-board antenna configuration and the elevation angle. For a transparent payload embodiment, the satellite may apply radio frequency (RF) filtering, frequency conversion, and amplification, but does not change the waveform of the signal. For a regenerative payload embodiment, the satellite may apply RF filtering, frequency conversion, amplification, demodulation and decoding, routing, and coding / modulation. This regenerative payload approach implements most of the BS’s functions (e.g., of an eNB).

[0006] The NB-loT and eMTC technologies are expected to be particularly suitable for loT devices operating in remote areas with limited or no terrestrial connectivity. Such loT devices can be used in a variety of industries including, for example: transportation (maritime, road, rail, air) and logistics; solar, oil, and gas harvesting; utilities; farming; environmental monitoring; and mining. In order to ensure the requiredAttorney Docket No.: 0683-121 -WOloT connectivity, the NTN deployments provide coverage complementary to the terrestrial deployments.

[0007] A public warning system (PWS) is a system that delivers (e.g., broadcasts) notifications (i.e. , PWS messages) to UEs in an alert area through a 3GPP network. The term “PWS” covers a commercial mobile alert system (CMAS) and an Earthquake and Tsunami Warning system (ETWS). PWS messages notify users in the alert area of an event (e.g., an earthquake) that may affect them. A BS typically broadcasts PWS messages to the UEs in a cell via a terrestrial network (TN) (for example, via a tower) or an NTN network using a satellite. Because the coverage of a NTN cell is usually much larger than the alert area associated with the PWS message, many UEs located inside the NTN cell, but far from the alert area, may waste power and time to acquire, decode, and assess PWS information not actually relevant to them. Usually, for most the UEs in an NTN cell, the alert is not relevant because they are outside the alert area, thereby wasting UE power to acquire and decode further information. At times, more than one alert is applicable within an NTN cell. Applying the PWS mechanism separately, for each alert, is inefficient and time consuming, which wastes UE power and communication resources and may also delay the presentation of a relevant alert by the UE.SUMMARY

[0008] In order to reduce, to a relevant subset, the number of UEs within an NTN cell that acquire and process PWS messages, a BS communicating via a satellite provides coarse alert area information concurrently with a PWS indication. The BS may transmit the coarse alert area information and the PWS indication using a paging message, a system information block type 1 (SIB1), or another type of downlink message. The coarse alert area information may indicate subdivision PWS areas of the NTN cell (e.g., quadrants or other cell subdivisions, state / province, multicast-broadcast areas) or may define one or more PWS areas (e.g., indicating a radius and center coordinate) within the NTN cell.Attorney Docket No.: 0683-121 -WO

[0009] A UE receiving the coarse alert area information and the PWS indication selectively acquires and decodes a PWS message including alert details depending on whether the UE’s current location is within a PWS area (which covers the alert area defined in the detailed information) indicated via the coarse alert area information.

[0010] Alternatively or additionally, a BS communicating via a satellite selects a proper subset of (i. e. , less than all) a satellite’s beams. The proper subset includes the available satellite beams serving an area that overlaps an alert area. The BS uses only that subset of satellite beams to transmit PWS-related messages.

[0011] In some embodiments, the PWS message carries detailed alert information corresponding to plural PWS indications.BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate one or more embodiments and, together with the description, explain these embodiments.

[0013] Fig. 1 is a block diagram of a wireless communication system in which a UE and a BS perform methods according to various embodiments.

[0014] Fig. 2 is a block diagram illustrating an NTN arrangement with transparent payload embodiment.

[0015] Fig. 3 is a block diagram illustrating an NTN arrangement with regenerative payload embodiment.

[0016] Fig. 4 illustrates a conventional setup in which a PWS message is broadcasted via a TN cell and an NTN cell.

[0017] Figs. 5A and 5B illustrate different ways of conveying coarse alert area information.

[0018] Figs. 6A and 6B illustrate UE’s behavior upon receiving a paging message including a PWS indication and coarse alert area information according to an embodiment.Attorney Docket No.: 0683-121 -WO

[0019] Figs. 7A and 7B illustrate LIE’S behavior upon receiving a downlink control message including a PWS indication and coarse alert area information according to an embodiment.

[0020] Figs. 8A and 8B illustrate UE’s behavior upon receiving a paging message including a PWS indication and a bitmap or an ID list indicating a subset of preconfigured areas according to an embodiment.

[0021] Fig. 9 is a flowchart of a UE method for determining whether a UE is within at least one PWS area indicated by the coarse alert area information according to an embodiment.

[0022] Fig. 10 is a flowchart of a UE method for determining whether to acquire the PWS related system information, based on UE’s location, a coarse alert area using a reference location, and a bitmap included in the paging message or in the PDCCH, according to an embodiment.

[0023] Fig. 11 is a flowchart of another UE method for determining whether to acquire the alert details based on UE’s location and coarse alert area information that specifies center coordinates and a radius of a PWS area, according to an embodiment.

[0024] Fig. 12 is a flowchart of a UE method for determining whether to acquire the detailed alert information based on a coarse alert area configuration, according to an embodiment.

[0025] Fig. 13 is a flowchart of a UE method for acquiring system information upon detecting that the UE has moved into a coarse alert area after initially deferring to acquire the information, according to an embodiment.

[0026] Fig. 14 is a flowchart of a UE method for acquiring the configuration for a broadcast or multicast service area, upon detecting that the UE has moved into an area intended for a broadcast or multicast service, according to an embodiment.

[0027] Fig. 15 illustrates a proper subset of the available satellite beams that cover PWS area(s) overlapping an alert area within an NTN cell.Attorney Docket No.: 0683-121 -WO

[0028] Fig. 16 is a flowchart of a BS method for transmitting the alert indication and alert details through a subset of the available satellite beams, according to an embodiment.

[0029] Fig. 17 illustrates a conventional scenario according to which the BS serving an NTN cell signals each alert separately.

[0030] Fig. 18 is a signal diagram corresponding to the conventional scenario in Fig.17.

[0031] Fig. 19 illustrates a scenario with plural alerts signaled simultaneously in an NTN cell according to an embodiment.

[0032] Fig. 20 is a signal diagram corresponding to the scenario in Fig. 19.

[0033] Fig. 21 is a flowchart of a BS method according to an embodiment.DETAILED DESCRIPTION OF THE DRAWINGS

[0034] Methods and devices described in this section embody techniques related to methods and devices enhancing PWS notification in NTN cells. The embodiment descriptions in this section refer to the accompanying drawings. The same reference numbers in different drawings identify the same or similar elements. The detailed descriptions do not preclude other embodiments within the scope of the appended claims. The embodiments are not limited to the described configuration but may be extended to other arrangements.

[0035] Before describing various embodiments, Fig. 1 illustrates a wireless communication system 100 that includes a UE 102, a base station (BS) 104, a BS 106, and a core network (CN) 110. The BSs 104 and 106 are connected to the CN 110 via radio access network (RAN) 105. The CN 110 may be or include an evolved packet core (EPC) 111 and / or a fifth generation (5G) core (5GC) 160. The CN 110 may also be or include a sixth generation (6G) core (not illustrated in Fig. 1).

[0036] The BS 104 covers an NTN cell 124, and the BS 106 covers a TN cell 126. If the BS 104 is a gNB, the NTN cell 124 is an NR cell. If the BS 104 is an ng-eNB or eNB,Attorney Docket No.: 0683-121 -WOthe NTN cell 124 is an evolved universal terrestrial radio access (E-UTRA) cell.Similarly, if the BS 106 is a gNB, the TN cell 126 is an NR cell, and if the BS 106 is an ng-eNB or eNB, the TN cell 126 is an E-UTRA cell. The cells 124 and 126 may belong to the same Radio Access Network Notification Areas (RNA) or different RNAs. In general, a RAN such as the RAN 105 may include any number of BSs, and each of the BSs may cover one, two, three, or any other suitable number of TN / NTN cells. The UE 102 may communicate via a 5G NR (or simply, “NR”) and / or E-UTRA air interface with the BSs 104 and 106. Each of the BSs 104 and 106 connect to the CN 110 via an interface (e.g., an S1 or an NG interface). The BSs 104 and 106 may be interconnected via an interface (e.g., an X2 or an Xn interface). The cells 124 and 126 partially overlap, so that the UE 102 can select, reselect, or hand over from one of the cells 124 and 126 to the other.

[0037] Among other components, the EPC 111 typically includes a Mobility Management Entity (MME) 112, a Serving Gateway (SGW) 114, and a Packet Data Network Gateway (PGW) 116. The MME 112 is configured to manage authentication, registration, paging, and other related functions. The SGW 114 is configured to transfer user-plane packets related to audio calls, video calls, Internet traffic, etc. The PGW 116 provides connectivity from the UE to one or more external packet data networks (e.g., an Internet network and / or an Internet Protocol (IP) Multimedia Subsystem (IMS) network). The 5GC 160 typically includes at least one instance of Access and Mobility Management Function (AMF) 162, a Session Management Function (SMF) 164, and a User Plane Function (UPF) 166. The AMF 162 is configured to manage authentication, registration, paging, and other related functions, the SMF 164 is configured to manage PDU sessions, and the UPF 166 is configured to transfer user-plane packets related to audio calls, video calls, Internet traffic, etc. The CN 110 can connect to any suitable number of BSs supporting NR cells and / or EUTRA cells.

[0038] As discussed in detail below, the UE 102 and / or the BS 104 may use the paging techniques described below when the radio connection between the UE 102 and the RAN 105 is suspended, e.g., when the UE 102 operates in an inactive or idle state of the protocol for controlling radio resources between the UE 102 and the RAN 105.Attorney Docket No.: 0683-121 -WO

[0039] The BS 104 is typically equipped with processing hardware 130 that includes one or more processors (e.g., central processing units (CPUs) and / or special-purpose processing units (SPUs)) and a non-transitory computer-readable memory storing instructions that the one or more processors execute. The processing hardware 130 illustrated in Fig. 1 includes a processor 132 to process data that the BS 104 transmits in the downlink (DL) direction, and / or data that the BS 104 receives in the uplink (UL) direction. The processing hardware 130 also includes a transmitter 136 configured to transmit data in the DL direction and a receiver 134 configured to receive data in the UL direction. As discussed later and illustrated in Figs. 2 and 3, the BS 104 may be on the ground communicating via satellite 103 with the UE 102, or on the satellite 103. The BS 106 includes generally similar components as the BS 104. In this document, the combination transceiver and receiver is sometimes called transceiver.

[0040] The UE 102 is equipped with processing hardware 150 that includes one or more processors such (as CPUs and SPUs) and non-transitory computer-readable memory storing machine-readable instructions executable on the one or more processors. The processing hardware 150 includes a processor 152 to process data that the UE 102 transmits in the UL direction, and / or data that the UE 102 receives in the DL direction. The processing hardware 150 also includes a transmitter 156 configured to transmit data in the DL direction and a receiver 154 configured to receive data in the UL direction.

[0041] Fig. 2 illustrates a transparent payload NTN deployment 200, which involves a satellite gateway 202 and a “transparent” satellite 103. The satellite 103 may be configured to perform a frequency conversion and an RF amplification in both the UL and DL directions. In such a transparent payload NTN deployment, the satellite 103 generally operates similarly to an analogue RF repeater. As a result, the satellite 103 repeats a signal received on the feeder link (between the NTN gateway and the satellite) to the service link (between the satellite and the UE) in the DL direction and vice versa in the UL direction. The Satellite Radio Interface (SRI) on the feeder link is a Uu interface, and the NTN gateway 202 supports all necessary functions to forward the signal of the Uu interface. The NTN gateway 202 may be collocated with the BS 104 or may be connected to the BS 104 via a wired link. The BS 104 may be connected toAttorney Docket No.: 0683-121 -WOmore than one NTN gateway. Different transparent satellites may be connected to the same BS on the ground, via the same NTN gateway, or via different NTN gateways. In addition, as the UE 102 needs to know its position in order to compensate the time and frequency drift while transmitting data / signal to a moving satellite, the UE 102 also needs to obtain / measure the signal emitted from at least one Global Navigation Satellite System (GNSS) satellite 208.

[0042] Fig. 3 illustrates a regenerative payload NTN deployment 300, which involves a satellite gateway 302 and a “regenerative” satellite 103 with the BS 104 and, optionally, also a part of the MME 112 (i.e. , split-MME) or the entire MME 112 installed on it. The service link between the satellite 103 and the UE 102 carries the signals of the Uu interface. When only the BS 104 is located on the satellite, the Satellite Radio Interface (SRI) on the feeder link carries also the S1 or NG interface besides the Uu interface. That is, the NTN gateway 302 placed at one end of the SRI / feeder link serves as an intermediate node forwarding the S1 / NG traffic between the BS 104 and the CN 110. In some examples of the regenerative satellite payload architecture, the part of the MME 112 or the entire MME 114 also installed on the “regenerative” satellite, and hence feeder link does not carry either the S1 interface or NG interface (it only carries the internal interface within a core network node). Different regenerative satellites can connect to the same CN 110 on the ground, via the same NTN gateway, or via different NTN gateways.

[0043] The techniques of this disclosure apply to both transparent payload and regenerative payload deployment.

[0044] 3GPP communication systems introduced Commercial Mobile Alert System (CMAS) and Earthquake and Tsunami Warning System (ETWS) as Public Warning System (PWS) services utilizing the cell broadcast capability. Through the CMAS and ETWS, the authority or the government can broadcast text-based alerts and warnings to the public in an alert area covered by a single or multiple cells. UEs within the alerting area receive and may display the alert to the user (if the UEs are enabled to receive warning messages and can act accordingly). As satellite is by nature a broadcast medium, it can quickly reach very large coverage areas even when terrestrial networksAttorney Docket No.: 0683-121 -WO(TN) are down. 3GPP decided to develop the broadcasting of emergency messages via NTN cells because delivery of the same data to a very large number of UEs in the alert area via Unicast is not scalable. Thus, supporting broadcast of PWS messages for NB-loT re-using the LTE mechanisms has become a subject (objective) of further developments. Solutions developed for NTN cells may be applied to TN. Support for indication of intended service area for ETWS is considered for NR NTN cells.

[0045] Fig. 4 illustrates a conventional setup 400 in which an alert-related message (e.g., CMAS-related SIB12 in LTE, ETWS-related SIB10 or SIB11 in LTE, or PWS-related SIB8 in 5G) is broadcasted via an NTN cell 124 and a TN cell 126. When warning UEs becomes necessary (e.g., an emergency situation occurs), a Cell Broadcast Entity (CBE) 472 formats alert-related information (including, if necessary, splitting of an alert-related message) and then transmits the alert-related message(s) to a Cell Broadcast Center (CBC) 474. The CBC 474 then packs the alert-related message(s) generated by the CBE 472 and transmits these packed messages to the MME 112 (or AMF 162 in 5G). The CBC 474 allocates serial numbers to thealert-related message(s) and determines the cells which to broadcast the alert-related messages, for how long to broadcast the alert-related message(s), and how frequent to broadcast the alert-related message(s). The MME 112 then transmits the alert-related message(s) to the BS 106 (e.g., an E-UTRAN BS, that is, an eNB) of a terrestrial network. In response to the alert message(s), the eNB 106 repeatedly broadcasts a paging message containing an alert (or PWS) indication (e.g., cmas-lndication) in the entire TN cell 126, and concurrently also broadcasts system information blocks (i.e. , SIB10 / 11 / 12 in LTE or SIB8 in 5G) carrying alert details (i.e., the alert message(s)).

[0046] Upon receiving the paging message including the alert (PWS) indication, the UE 102 proceeds to acquire SIB12 (and SIB1, before acquiring SIB12) and extracts the detailed information related to the alert from the SIB12. If the geo-fencing information (e.g., warnmgAreaCoordinatesSegment) is included in SIB12, the UE 102 is able to determine whether to react (e.g., to display the alert message(s) that may also be conveyed via SIB12 or may be otherwise predefined) based on UE’s current location and the geo-fencing information. The geo-fencing information in SIB12 here includes the coordinates (e.g., latitude and longitude) of five vertices defining a pentagonAttorney Docket No.: 0683-121 -WOmapping the alert area 430. In Fig. 4, the UE 102 is outside the alert area 430 (which covers only about half of the TN cell 126) and thus does not need to react to the alert message.

[0047] However, the MME 112 may (alternatively or additionally to transmitting the alert message to BS 106) transmit the alert message(s) to a RAN 105 node (i.e., BS 104) onboard the satellite 103. The MME may choose this alternative when most of the ground BSs are not available due to the disaster and the feeder-link between the NTN gateway 402 and the satellite 103 is still available. In response to receiving the alert message(s), the BS 104 onboard the satellite 103 repeatedly broadcasts a paging message containing an alert indication (e.g., cmas-lndication') in the entire NTN cell 124, and concurrently also broadcasts the system information (e.g., SIB12 indicated by SIB1) carrying the detailed alert information. Conventionally, the paging message includesand the SIB12 includes

[0048] Because the area of the NTN cell 124 is much larger than that of the TN cell 126, most of the UEs within the NTN cell 124 do not need to react to the alert message, as they are outside the alert area 430. However, as these UEs (within the NTN cell 124 but outside the alert area) still receive the paging message including the alert indication, they further acquire SIB12 to determine whether to react. Note that time required forAttorney Docket No.: 0683-121 -WOacquiring the entire SIB12 could be very long due to the segmentations of SIB12. The aggregate power used by all the UEs that do not need the detailed alert information is significant and wasted.

[0049] To alleviate the UE power waste, the simplest solution seems to be conveying the geo-fencing information (e.g., warningAreaCoordinatesSegmenf) also via the paging message. However, the geo-fencing information may be large because it may include coordinates of up to 100 vertices. Including such a large amount of information in the paging message may cause significant signaling overhead considering that the paging message is broadcasted repeatedly in each paging frame. To achieve a good tradeoff between saving UE power and overhead signaling, according to the following embodiments, the paging message may include coarse alert area information indicating a PWS area covering the alert area defined by the geo-fencing information. The coarse alert area information ensures that UEs in the alert area are warned and requires less communication resources (bits) than the geo-fencing information would. Based on the coarse alert area information, the UE is able to assess whether to acquire the detailed alert information (e.g., SIB12). The number of UEs acquiring the detailed alert information is thus substantially reduced.

[0050] Figs. 5A and 5B illustrate different ways of conveying coarse alert area information. In discussing various embodiments, geo-fencing information (which is part of the detailed alert information) defines an alert area like 430 in Figs. 5A and 5B, while the coarse alert area information indicates or defines a PWS area (i.e. , a coarse alert area, e.g., quadrant III in Fig. 1 A and 534 in Fig. 5B) that overlappingly covers the alert area and it is smaller than the NTN cell. In the scenario 500 illustrated in Fig. 5A, the NTN cell 124 is divided into four quadrants (labeled as I, II, III, and IV) around a reference location 531. Although the sub-dividers of the NTN cell are shown based on the latitude and longitude of the reference location, other sub-dividers may be implemented. These include state / province or other geopolitical subdivisions. The paging message carrying the alert indication also includes a N-bit long bitmap (here N=4 but this value is illustrative, not intended to be limiting) indicating whether any alert area is present within the quadrants. The four quadrants are mapped to 1st, 2nd, 3rd, and 4thbit in the bitmap, respectively; a bit value T or ‘true’ indicates a presence of at leastAttorney Docket No.: 0683-121 -WOan alert area in the corresponding quadrant, while a bit value ‘0’ or ‘false’ indicates no alert area in the corresponding quadrant. The reference location 531 may also be specified in the paging message, but the UE 102 may alternatively also obtain the coordinates of the reference location from information conveyed via another message (e.g., SIB31). In the scenario 500, the alert area 430 is included in quadrant III, and therefore, the values of the bitmap are {0, 0, 1 , 0}. Note that the alert area may have portions in more than one quadrant, and the bitmap may contain multiple T. The paging message for this scenario is

[0051] In the scenario 550 illustrated in Fig. 5B, the paging message carrying the alert (PWS) indication (e.g., cmas ndication) also specifies a PWS area 534 by including the coordinate(s) of this area’s center 532 and the area’s radius. In one embodiment, the size (e.g., big, small, medium) of the PWS area 534 is signaled (instead of the radius of the PWS area 534) in the paging message to further reduce the signaling overhead. The definition of the size (e.g., big, small, medium) must be commonly understood (interpreted in the same way) between the network and the UEs. Thus, the paging message for this scenario is

[0052] Figs. 6A, 6B, 7A, 7B, 8A, and 8B illustrate UE’s behavior upon receiving coarse alert area information together with an alert indication (i.e., a PWS indication thatAttorney Docket No.: 0683-121 -WOmay be a CMAS or an ETWS indication). Similar events (i.e. , actions or signals) in these figures are labeled with reference numbers that have the same lower-order digits. For example, event 644 is similar to events 744 and 844, and event 650 is similar to event 850. Events with the same label may occur in multiple figures, which implies that there are no significant differences between the different instances. For brevity, similar events are not described in detail for each instance, and events carrying the same label are described only with reference to one (first) instance. The time flows from top to bottom, events illustrated higher in a figure occurring earlier than events illustrated lower therein.

[0053] Figs. 6A and 6B illustrate LIE’S behavior upon receiving a paging message including a PWS indication and coarse alert area information. That is, the UE 102 determines whether to acquire a PWS message including detailed alert information based on the coarse alert area information in the paging message. In both the scenario 600A illustrated in Fig. 6A and the scenario 600B illustrated in Fig. 6B, the UE 102 is initially 642 in an RRC_CONNECTED, an RRCJDLE, or an RRCJNACTIVE state. Thus, the UE 102 connects to or synchronizes with the BS 104 via the satellite 103. The BS 104 may be installed onboard the satellite 103 (i.e., the regenerative payload deployment as illustrated in Fig. 3) or may be on the ground connected to the satellite gateway 202 (i.e., a transparent payload deployment as illustrated in Fig. 2).

[0054] If the UE 102 is in the RRC_CONNECTED state, the UE 102 then monitors a Paging Occasions (PO) once per System Information Modification Period, and determines to acquire 644 a Paging message scheduled by the PDCCH within the PO that the UE 102 monitors. If the UE 102 is in the RRCJDLE or RRCJNACTIVE state, the UE 102 monitors and acquires 644 the Paging message in UE’s PO once per paging cycle, where UE’s PO is calculated and determined based on UE’s identity (e.g., an international mobile subscriber identity (IMSI), or a 5G shortened temporary mobile subscriber identity (5G-S-TMSI)) and other paging configurations. If the UE 102 is an NB-loT UE, it receives a Paging-NB message instead of a Paging message.

[0055] The Paging message includes an alert indication (e.g., a PWS, a CMAS or an ETWS alert) and coarse alert area information. The coarse alert area informationAttorney Docket No.: 0683-121 -WOindicates at least one PWS area overlapping the alert area(s) specified in detail, for example, in the later-received SIB12 or SIB8. However, the PWS area is indicated or defined using just a few bits of the Paging message. As previously described relative to Fig. 5A, the coarse alert area information may include a reference location and a bitmap. The reference location is used to divide the NTN cell into 4 quadrants, for example, separated by East-to-West and Noth-to-South imaginary lines crossing at the reference location. The bitmap is used to indicate which quadrant(s) is / are affected by the alert. If the reference location is not specified as part of the coarse alert area information, the UE 102 may infer the reference location from SIB31 information because SIB31 conveys ephemeris data for the satellite position and velocity. The coarse alert area information may specify multiple PWS areas, with each PWS area being described using center coordinates and a pre-defined size (e.g., big, medium, or small) or a radius (e.g., in kilometers).

[0056] After receiving 644 the Paging (or Paging-NB) message from the BS 104, the UE 102 identifies 650 the PWS area(s) (that cover the alert area(s)) based on the coarse alert area information. Figs. 5A and 5B illustrate two techniques of defining and thus conveying information about the PWS area(s), but other techniques are not precluded. The UE 102 also obtains 652 UE GNSS coordinates (e.g., latitude and longitude values) from UE’s GNSS module. Although event 652 is illustrated after event 650 in Figs. 6A, 6B, 7A and 7B, event 652 may alternatively occur before or simultaneously with event 650. In the scenario 600A, the UE then 102 determines 654, based on the UE GNSS coordinates and the identified area(s), that the UE 102 is not within any PWS area. The UE then disregards 656 the PWS indication taking no further action. The UE 102 may then “go back to sleep” (i.e. , switch to a low power state) if the UE 102 has been at 642 in the RRCJDLE or RRCJNACTIVE state and the UE’s identifier does not appear in another paging message.

[0057] In the scenario 600B illustrated in Fig. 6B, after events 650 and 652, the UE 102 determines 653, based on the UE GNSS coordinates and the identified PWS area(s), that the UE is within at least one PWS area. In view of 653, the UE 102 acquires 658 SIB1 and SIB12 (or SIB 10 or SIB 11 , or SIB8 in case of a 5G communication system) that include the detailed alert information. The BS transmitsAttorney Docket No.: 0683-121 -WO657 SIB1 that schedules upcoming SIB12 and then transmits 659 SIB12. The UE 102 may then display 660 the alert message based on the information in SIB12. In one embodiment, the UE 102 determines to display an alert message extracted from SIB12 because the UE is within the alert area determined based on the geo-fencing information (e.g., IE warningAreaCoordinatesSegment) included in SIB12, or because the geo-fencing information is not included in S IB 12. In another embodiment, the UE 102 determines not to display the alert message carried in SIB12 as the UE is not within the alert area identified based on the geo-fencing information included in SIB 12. If the UE 102 is an NB-loT UE, the UE 102 acquires SIB1-NB and SIB10-NB / SIB11 -NB / SIB12-NB instead of acquiring SIB1 and SIB10 / 11 / 12.

[0058] Figs. 7A and 7B illustrate UE’s behavior upon receiving a downlink control message including an alert indication and coarse alert area information according to an embodiment. That is, unlike in scenarios 600A and 600B illustrated in Figs. 6A and 6B, in scenarios 700A and 700B in Figs. 7Aand 7B, the BS 104 transmits 744 the alert indication and coarse alert area information in a control message via a Physical Downlink Control Channel (PDCCH, which may be a machine type communication (MTC) PDCCH (MPDCCH) or a narrow band PDCCH (NPDCCH)) to the UE 102. The UE monitors and receives 744 the control message on PDCCH. The control message schedules a Paging message if at least one UE is being paged. If the UE 102 is an enhanced MTC (eMTC) UE, the UE monitors and receives 744 the control message scheduling as a Paging-NB message on MPDCCH. If the UE 102 is an NB-loT UE, the UE monitors and receives 744 the control message scheduling as a Paging-NB message on an NPDCCH. The control message received on PDCCH, MPDCCH, or NPDCCH further includes an alert indication and coarse alert area information. The UE 102 then identifies 650 the PWS areas and the scenarios 700A and 700B continue with the same events as the scenarios 600A and 600B respectively.

[0059] Figs. 8A and 8B illustrate UE’s behavior upon receiving a paging message including an alert indication and a bitmap or an ID list indicating a subset of preconfigured areas according to an embodiment. Figs. 8A and 8B illustrate scenarios 800A and 800B in which the UE 102 is (as the previously described scenarios) initially 642 in the RRC_CONNECTED, RRCJDLE, or RRCJNACTIVE state. The UE 102Attorney Docket No.: 0683-121 -WOthen receives 843 system information (e.g., a new SIB not yet defined in 3GPP technical specifications) including a PWS area configuration. The PWS area configuration specifies center coordinates, a radius, and an index (or an identifier (ID)) for each configured PWS area. The PWS area configuration may not provide explicitly the indexes, but they are implicit in the order / sequence in which the PWS area configuration specifies the PWS areas. The BS may transmit the PWS area configuration to the UE 102 via a dedicated radio resource control (RRC) message (e.g., an RRC Connection Reconfiguration message) instead of via the system information. In one implementation, the geographical areas and the associated identities / indices configured for other purpose (e.g., the intended areas for the broadcast or multicast service (MBS), or the TN areas) can be used and referred as the PWS areas.

[0060] The UE 102 then receives 844 a Paging (or a Paging-NB) message including an alert indication and a bitmap or a list of IDs. The bitmap or the list of IDs indicates one or more of the configured PWS area(s) affected by the alert. In some other embodiments, the BS 104 includes the alert indication and the bitmap or the list of IDs in a control message transmitted on a PDCCH, MPDCCH, or NPDCCH. In the bitmap, the value T or ‘true’ in the kthbit indicates that the alert affects the kthconfigured PWS area, while the value ‘0’ or ‘false’ in the same position indicates that the alert does not affect the kthconfigured PWS area. The UE 102 then obtains 652 the UE GNSS coordinates from the GNSS module and identifies 850 a configured PWS area where the UE 102 is located. In the scenario 800A, the UE 102 then determines 854 that the configured PWS area where the UE 102 is located is not among the PWS area(s) affected by the alert (according to the bitmap or the list of IDs). As in scenarios 600A and 700A, the UE 102 then disregards 656 the alert indication and may “go back to sleep” if the UE 102 is originally in the RRCJDLE or RRCJNACTIVE state and the UE ID does not appear in the Paging (or Paging-NB) message.

[0061] In the scenario 800B, the UE 102 determines 853 that the UE is located in one of the PWS areas affected by the alert. Therefore, the UE 102 acquires 658 the SIB1 (or SIB1-NB) and the SIB including detailed alert information (e.g., SIB10 / 11 / 12, or SIB10-NB / SIB11-NB / SIB12-NB) transmitted by the BS 104 (657 and 659). As describedAttorney Docket No.: 0683-121 -WOrelative to Fig. 6B, the UE 102 may the display 660 the alert message based on the information in SIB10 / 11 / 12 (or SIB10-NB / SIB11-NB / SIB12-NB).

[0062] Fig. 9 is a flowchart of a UE method 900 for determining whether a UE is within any PWS area indicated by the coarse alert area information, according to an embodiment. Initially, the UE operates 942 in the RRC_CONNECTED, RRCJDLE, or RRCJNACTIVE state and connects to or synchronizes with a BS (e.g., 104) via a satellite (103). The BS may be on the ground or on the satellite. The UE optionally receives 943, from the BS, the system information including a PWS area configuration configuring a set of PWS areas. Alternatively, the PWS area configuration can be predetermined. The PWS area configuration associates an index number or an identity to each PWS area (explicitly or implicitly). The UE then receives 944, from the BS, a Paging message or a PDCCH (or MPDCCH or NPDCCH) including an alert indication and coarse alert area information which may refer to the PWS areas configured at 943.

[0063] The UE obtains 952 the UE GNSS position (e.g., UE’s GNSS coordinates) from the GNSS module (after, concurrently or before 944). The UE then determines 955, based on the UE GNSS position, whether the UE is within one of the PWS area(s) indicated by the coarse alert area information that corresponds to the alert indication. If the UE determines that the UE is not in an alert affected area (i.e. , the “NO” branch of 955), the UE disregards 956 the alert indication (and may then switch to a low power state if the UE was initially in the RRCJDLE or RRCJNACTIVE state). If however, the UE determines that the UE is in an alert affected area (i.e., the “YES” branch of 955), the UE proceeds to acquire 958 the relevant system information blocks (e.g., SIB1 and SIB10 / 11 / 12) in response to the alert indication.

[0064] Fig. 10 is a flowchart of a UE method 1000 for determining whether to acquire the system information carrying alert details, based on UE’s location and coarse alert area information included in the paging message or a control message transmitted on the Physical Downlink Control Channel (PDCCH) according to an embodiment. The UE receives 1044, from the BS, a Paging message (or a Paging-NB message, if the UE is an NB-loT UE) or a PDCCH including an alert indication and coarse alert area information including a bitmap indicating affected areas. The UE determines 1045Attorney Docket No.: 0683-121 -WOwhether the coarse alert area information specifies a reference location. If the UE determines that the coarse alert area information does not specify a reference location (i.e., the “NO” branch of 1045), the UE then obtains 1047 the reference location from SIB31 (i.e., ephemeris information about the satellite 103). After step 1047, if the UE determines that the coarse alert area information specifies the reference location (i.e., the “YES” branch of 1045), the UE identifies 1050 the alert affected area(s) based on the reference location, NTN cell sub-dividers, and the bitmap. Further, the UE obtains 952 the UE GNSS position (e.g., UE’s GNSS coordinates) from the GNSS module, and then determines 1055 whether the UE is within one of the alert affected area(s). If the UE determinates that the UE is not within any of the alert affected area(s) of (i.e., the “NO” branch of 1055), the UE disregards 956 the alert indication and switches to a low power state if the UE was initially in the RRCJDLE or RRCJNACTIVE state. If, however, the UE determines that the UE is within at least one of the alert affected area(s) (i.e., the “YES” branch of 1055), the UE proceeds to acquire 958 the relevant system information blocks (e.g., SIB1 and SIB10 / 11 / 12).

[0065] Fig. 11 is a flowchart of a UE method 1100 for determining whether to acquire the alert details based on UE’s location and coarse alert area information that specifies center coordinates and a radius of a PWS area, according to an embodiment. In this method, the UE receives 1144, from the BS, a Paging message (or a Paging-NB message, if the UE is an NB-loT UE or a control message on PDCCH, MPSCCH or NPDCCH) including an alert indication and coarse alert area information. The coarse alert area information includes the center coordinate(s) and radius(s) of alert affected area(s) (as in the scenario 550 in Fig. 5B). The UE identifies 1150 the alert affected area(s) based on the coarse alert area information (i.e., the center coordinate(s) and radius(s) of alert affected area(s)) and, as in methods 900 and 1000, the UE obtains 952 the UE GNSS position (e.g., UE’s GNSS coordinates) from the GNSS module. The UE then continues with steps 1055 followed by 956 or 958 as described relative to the method 1000.

[0066] Fig. 12 is a flowchart of a UE method 1200 for determining whether to acquire detailed alert information, based on a PWS area configuration and a bitmap of a list of ID(s) included in the paging message and specifying alert affected area(s) among theAttorney Docket No.: 0683-121 -WOconfigured areas. Here, the UE receives 1243, from a BS, system information including a PWS area configuration that includes center coordinates, a radius, and an index (or an ID) for each PWS (i.e. , configured) area. The UE then receive 1244, from the BS, a Paging message (or a Paging-NB message, if the UE is an NB-loT UE) or a control message on PDCCH including an alert indication and a bitmap or a list of ID(s). The UE then identifies 1250 the alert affected area(s) based on the PWS area configuration and the bitmap or the list of ID(s) included in the Paging message or in the PDCCH.

[0067] Similar to the previously described methods, the UE then obtains 952 the UE GNSS position (e.g., UE’s GNSS coordinates) from the GNSS module, and then continues with steps 1055, and 956 or 958 previously described.

[0068] Fig. 13 is flowchart of a UE method 1300 for acquiring detailed alert information upon detecting that the UE has moved into an alert area after initially deferring to acquire the detailed alert information, according to an embodiment. After the previously described steps 942, 944, the UE obtains 1352A a first UE GNSS position from the GNSS module and determines 1354 that the first UE GNSS position is outside (alert affected) PWS area(s) indicated by the coarse alert area information. The UE then disregards 956 the alert indication.

[0069] The moving UE later obtains 1352B a second UE GNSS position from the GNSS module. Based on the second UE GNSS position, the UE determines 1353 that the UE is within one of the (alert affected) PWS area(s) indicated by the coarse alert area information. The UE then acquires 1357 SIB1 (even if the UE remains in the same NTN cell and no system information update procedure has been triggered). That is, unlike conventional UEs that do not acquire SIB1 / SIB12 while in the same cell and not being paged, here the UE acquires SIB1 / SIB12 again when the UE enters a PWS area even if the UE remains in the same cell. The UE then determines whether the SIB1 schedules an SIB (e.g., SIB12 or SIB8) that includes alert details. If indeed the SIB1 indicates such an upcoming SIB (i.e., the “YES” branch of 1355), the UE acquires 1359 this SIB, otherwise the UE takes 1356 no further action.

[0070] Fig. 14 is a flowchart of a UE method 1400 for acquiring a broadcast or multicast service configuration selectively detailed service information. Initially, the UEAttorney Docket No.: 0683-121 -WOreceives 1444, from a BS, system information including a channel configuration fora broadcast or multicast service and geo-fencing information indicating a broadcast or multicast service area. The channel configuration for the broadcast or multicast service may be a multicast control channel (MCCH) and multicast traffic channel (MTCH) configuration for a Multicast-Broadcast Service (MBS) included in SIB20 (in NR) and the geo-fencing information is the intended area information included in another SIB. The UE then obtains 1452 a UE GNSS position from the GNSS module, and determines 1455, based on the UE GNSS position, whether the UE is inside the broadcast or multicast service area. If the UE is outside the broadcast or multicast service area (i.e., “NO” branch of 1455), the UE disregards 1456 the channel configuration for the broadcast or multicast service. However, if the UE is inside a broadcast or multicast service area (i.e., “YES” branch of 1455), the UE acquires 1459 relevant system information blocks (e.g., SIB1 and SIB12) to receive detailed alert information.

[0071] Figs. 15 and 16 describe a BS-centric technique of reducing the number of UEs acquiring detailed alert information. The scenario 1500 illustrates a subset of the satellite beams useable for the NTN cell 124, with each satellite beam in the subset serving area(s) collectively and overlappingly covering an alert area 430. Here, the satellite 103 is part of RAN 105 that include a BS (not shown, may be located on the ground or on the satellite as illustrated in Figs. 2 and 3) serving UEs within the NTN cell 124 using plural satellite beams. When the RAN node (i.e., the BS) receives a PWS alert message from a CN node (e.g., an MME or an AMF), the RAN node identifies the alert area 430 based on the geo-fencing information associated with the alert. The RAN node also determines a proper subset of the available satellite beams, the beams in the subset being directed to areas 1531, 1532, 1533, 1534, and 1535 that collectively and overlappingly include the alert area 430. The satellite then transmits the alert indication and the alert detailed information using only the NTN beams in the subset, thereby, the alert indication and the alert detailed information being received only by UEs in the areas 1531 , 1532, 1533, 1534, and 1535, and not by all the UEs in the NTN cell 124.

[0072] Fig. 16 is a flowchart of a BS method 1600 for transmitting the alert indication and alert details through a subset of the available satellite beams according to an embodiment. The BS initially transmits 1641 a first SIB1 via all the beams covering theAttorney Docket No.: 0683-121 -WONTN cell (this is an optional step as suggested by the dashed line). The BS then receives 1670, from a CN node, a CN-to-BS message including an alert message and geo-fencing information for the alert. The CN-to-BS message may be an NG Application Protocol (NGAP) message or a S1 Application protocol message (S1AP) message. In some embodiments, the CN-to-BS message is a WRITE-REPLACE WARNING REQUEST message.

[0073] The BS then identifies 1672 at least one beam, which covers less than the full NTN cell, that covers an area identified by the geo-fencing information and then transmits 1644 the Paging message (or the MPDCCH / NPDCCH) including an alert indication and only through the at least one beam. The BS then transmits 1657 a second SIB1 using only the at least one beam. This second SIB1 schedules the system information block (e.g., SIB12) that carries the alert details. At the scheduled timing indicated in the second SIB1, the BS transmits 1659 the system information block with the alert details using only the at least one beam. The at least one beam is a proper subset of the plurality of beams that form the full NTN cell. The base station may use a tag value to indicate whether an SIB1 is the first SIB transmitted via all the satellite beams or the second SIB1 transmitted via the at least one beam.

[0074] Fig. 17 illustrates a conventional scenario 1700 according to which the BS serving an NTN cell signals each alert separately. The conventional BS (not shown, which may be located on the ground or on satellite 103 as illustrated in Figs. 2 and 3) sends separately detailed alert information (e.g., SIB1+SIB12) corresponding to different alerts. In this scenario, there are two simultaneous alert situations, a first alert affecting area 1732 and a second alert affecting area 1734. The BS transmits first detailed alert information (e.g., SIB1+SIB12) related to the first alert, followed by a number of transmission repetitions during the first alert duration. After transmitting all the repetitions related to the first alert, the BS transmits second detailed alert information (e.g., SIB1+SIB12) related to the second alert (and respective transmission repetitions). The UEs (such as UE 102A, UE 102B, and 102C) inside the NTN cell 124, receive and decode / process both the first and the second detailed information as illustrated in the signal diagram 1800 in Fig. 18.Attorney Docket No.: 0683-121 -WO

[0075] In Fig. 18, similar to the LIE behavior illustrated in Figs. 6A, 6B, 7A, 7B, 8A, and 8B, the UEs 102A, 102B, and 102C are initially in an RRC_CONNECTED, RRCJDLE, or RRCJNACTIVE state (1831 A, 1831 B, and 1831C). The BS 104 sends 1844A, via the satellite 103, a Paging message including a first alert indication (related to the alert area 1732) in the NTN cell 124 and also sends 1844B a second Paging message including a second alert indication (related to alert area 1734) in the NTN cell 124. The UEs 102A, 102B, 102C receive the first and the second paging message (but no coarse alert area information). The BS 104 then transmits 1833A an SIB1 signaling an upcoming SIB 12 and then sends 1835A the SIB12 (e.g., related to the alert in area 1732). Upon receiving the SIB12 including detailed alert information (including geofencing information defining area 1732) and obtaining UE 102A’s GNSS position (not shown), the UE 102A determines 1837A that it is within the alert area 1732 and may display 1838A the alert message related to the alert in the area 1732. Meanwhile, upon receiving this SIB12 and obtaining UE 102B’s GNSS position (not shown), the UE 102B determines 1847A that it is not within the alert area 1732 and takes no further action. Similarly, upon receiving this SIB12 and obtaining UE 102C’s GNSS position (not shown), the UE 102C determines 1848A that it is not within the alert area 1732 and takes no further action.

[0076] The BS 104 then transmits 1833B an SIB1 signaling an upcoming SIB12 and then sends 1835B the SIB12 (e.g., related to the alert in area 1734). Upon receiving the SIB12 including alert details (including geo-fencing information defining the area 1734) and obtaining UE 102As GNSS position (not shown), the UE 102A determines 1847B that it is not within the alert area 1734 and takes no further action. Similarly, upon receiving the SIB12 including alert details, and obtaining UE 102C’s GNSS position (not shown), the UE 102C determines 1848B that it is not within the alert area 1734 and takes no further action. Meanwhile, upon receiving this SIB12 and obtaining UE 102B’s GNSS position (not shown), the UE 102B determines 1837B that it is within the alert area 1734 and may display 1838B the alert message related to the alert in the area 1734. Many UEs similar to UE 102C might perform multiple [receive, obtain, no-action] and thus waste considerable time and energy.Attorney Docket No.: 0683-121 -WO

[0077] Fig. 19 illustrates a scenario 1900 with plural alerts (e.g., related to alert areas 1732 and 1734) signaled shortly one after another so their durations overlap, in an NTN cell according to an embodiment. In this scenario 1900, the BS serving the NTN cell (not shown, which may be located on the ground or on satellite 103 as illustrated in Figs. 2 and 3) sends simultaneously detailed alert information (e.g., the same SIB12) corresponding to different alerts. Thus, when there are multiple overlapping alerts (e.g., a first alert affecting area 1732 and a second alert affecting area 1734), the BS transmits both first detailed alert information related to the first alert and the second detailed alert information related to the second alert in the same SIB12 (followed by a number of transmission repetitions). The UEs (such as UE 102A, UE 102B, and UE 102C) inside the NTN cell 124, thus receive and process a single SIB12 with detailed information for both the alert affecting area 1732 and the alert affecting area 1734 as illustrated in the signal diagram 2000 in Fig. 20.

[0078] Unlike in the conventional approach illustrated in Figs. 17 and 18, the BS 104 sends 2035 simultaneously detailed alert information (e.g., in the same SIB12) corresponding to the alert affecting area 1732 and the alert affecting area 1734 (after sending 2033 an SIB1 signaling the upcoming SIB12). Upon receiving this SIB12 and obtaining UE 102A’s GNSS position (not shown), the UE 102A determines 2046A that it is within the alert area 1732 but not within the alert area 1734 (the areas 1732 and the area 1734 being specified by distinct geo-fencing information in SIB12). The UE 102A may then display 1838A the alert message related to the alert area 1732. Similarly, upon receiving the S IB 12 and obtaining UE 102B’s GNSS position (not shown), the UE 102B determines 2046B that it is within the alert area 1734 but not within the alert area 1732 may then display 1838B the alert message related to the alert area 1734. The UEs save power by decoding a single SIB 12 for both alerts, and the signal overhead is reduced by transmitting one instead of two SIB12s (and the preceding SIB1 s). Here, the UE 102C receives and processes a single SIB 12.

[0079] Fig. 21 is a flowchart of a BS method according to an embodiment. The method 2100 includes receiving 1670 a network public warning system, PWS, message including geo-fencing information indicating an alert area within the NTN cell. The method 2100 further includes generating 2174 coarse alert area information indicating aAttorney Docket No.: 0683-121 -WOPWS area geographically covering the alert area based on the geo-fencing information, and transmitting 2144, to a UE in the NTN cell, a first message including a PWS indication and the coarse alert area information. The method 2100 then includes transmitting 2159, to the UE, a second message with details related to an alert associated with the PWS indication and including the geo-fencing information.

[0080] The approach of FIG. 19 may be combined with FIG. 21. For example, the BS receives 1670 multiple network PWS messages with related geo-fencing information and generates 2174 coarse alert area information. The BS then transmits 2144 a paging (or other type of downlink control) message including the coarse alert area information indicating PWS area(s) with corresponding PWS indications. Continuing this example, the BS transmits 2157 a SIB1 and transmits 2159 an extended SIB12 including detailed alert information for multiple alerts.

[0081] Other NTN PWS-related improvements are now described (and further detailed in Annex A. One improvement is to trigger customized mobile terminated (MT) enhanced SOS (eSOS) messaging including a CMAS report. When a UE notes that its GPS location information needs to be updated to a satellite Gateway, the Gateway queries if there is a CMAS report for the specific location. If there is a CMAS report, the satellite gateway sends the UE a customized MT eSOS message with a CMAS report inside. Upon receiving the customized MT eSOS message, a UE performs CMAS decoding and displays the alert message. The advantage of this option is that it is controllable through the satellite Gateway.

[0082] Another improvement is to include multiple CMAS information and geo-fencing information into SIB broadcasting (already mentioned above). Yet another improvement is adding geographic information (e.g., geo-fencing information or coarse alert area information) to SIB1. Another possible improvement is to add country and state information into the detailed alert information (e.g., SIB1, SIB12 or SIB8). One or a combination of these improvements could save UE power without substantially increasing signaling overhead.

[0083] The following comments apply to the description above. The description for one of the above figures may apply to another of the figures. Any event or actionAttorney Docket No.: 0683-121 -WOdescribed above can be optional. For example, an event or action represented using dashed lines is optional. In some embodiments, “message” is used and can be replaced by “information element (IE)”, and vice versa. In some embodiments, “IE” is used and can be replaced by “field”, and vice versa. In some embodiments, “configuration” can be replaced by “configurations” or “configuration parameters”, and vice versa. The “eNB” can be replaced by “base station”, “gNB”, “6G base station”, “evolved gNB” or 6G gNB. “MME” can be replaced by AMF or evolved AMF or 6G AMF. “Core network (CN)” can be replaced by EPC or 5GC or future core network generations. “SIB10”, which refers to LTE SIB Type 10 for ETWS primary alert notifications, can be replaced by NR “SIB6” which serves a similar purpose. LTE “SIB11” which refers to LTE SIB Type 11 for ETWS secondary alert notifications, can be replaced by NR “SIB7”. LTE “SIB12” which refers to LTE SIB Type 12 for CMAS alert notifications, can be replaced by NR “SIB8”. “NPDCCH” or “MPDCCH” can be replaced by the short messages included in the DCI format 1_0 with CRC scrambled by P-RNTI.

[0084] A user device in which the techniques of this disclosure can be implemented (e.g., the UE 102) can be any suitable device capable of wireless communications such as a smartphone, a tablet computer, a laptop computer, a mobile gaming console, a point-of-sale (POS) terminal, a health monitoring device, a drone, a camera, a mediastreaming dongle or another personal media device, a wearable device such as a smartwatch, a wireless hotspot, a femtocell, or a broadband router. Further, the user device in some cases may be embedded in an electronic system such as the head unit of a vehicle or an advanced driver assistance system (ADAS). Still further, the user device can operate as an internet-of-things (loT) device or a mobile-internet device (MID). Depending on the type, the user device can include one or more general-purpose processors, a computer-readable memory, a user interface, one or more network interfaces, one or more sensors, etc.

[0085] Certain embodiments are described in this disclosure as including logic or a number of components or modules. Modules may be software modules (e.g., code, or machine-readable instructions stored on non-transitory machine-readable medium) or hardware modules. A hardware module is a tangible unit capable of performing certain operations and may be configured or arranged in a certain manner. A hardware moduleAttorney Docket No.: 0683-121 -WOcan comprise dedicated circuitry or logic that is permanently configured (e.g., as a special-purpose processor, such as a field programmable gate array (FPGA) or an application-specific integrated circuit (ASIC), a digital signal processor (DSP), etc.) to perform certain operations. A hardware module may also comprise programmable logic or circuitry (e.g., as encompassed within a general-purpose processor or other programmable processor) that is temporarily configured by software to perform certain operations. The decision to implement a hardware module in dedicated and permanently configured circuitry, or in temporarily configured circuitry (e.g., configured by software) may be driven by cost and time considerations.

[0086] When implemented in software, the techniques can be provided as part of the operating system, a library used by multiple applications, a particular software application, etc. The software can be executed by one or more general-purpose processors or one or more special-purpose processors. The methods or flowcharts may be implemented in a computer program, software or firmware tangibly embodied in a computer-readable storage medium for execution by a specifically programmed computer or processor.

[0087] Reference throughout this section to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout the specification are not necessarily all referring to the same embodiment. Further, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments.

[0088] Numerical adjectives “first”, “second”, and “third” do not imply any order (are not ordinals) but are markers to distinguish separate instances of similar elements. References to the singular (e.g., “a” or “an”, “the”) should include the plural unless clearly indicated otherwise.

[0089] As used herein, a phrase referring to “at least one of” or “one or more of” a list of items refers to any combination of those items, including single members. For example, “at least one of: a, b, or c” is intended to cover the possibilities of: a only, bAttorney Docket No.: 0683-121 -WOonly, c only, a combination of a and b, a combination of a and c, a combination of b and c, and a combination of a and b and c.

[0090] As discussed in more detail below, a UE and / or a network node of a radio access network (RAN) can use the techniques of this disclosure for managing the delivery and acquisition of the PWS alert message in the NTN environment.

Claims

Attorney Docket No.: 0683-121 -WOWHAT IS CLAIMED IS:

1. An alert communication-related method (900) performed by a user equipment, UE, (102), receiving services via a non-terrestrial network, NTN, cell (124), the method comprising:receiving (944) a first message including a first public warning system, PWS, indication and coarse alert area information indicating a first PWS area (534), which is smaller than the NTN cell, within the NTN cell;determining (955) whether the UE is in the first PWS area based on a UE’s current position and the coarse alert area information; andselectively acquiring (956) a second message including first alert details, including first alert content and first alert geo-fencing information, related to the first PWS indication when the UE is in the first PWS area.

2. The alert communication-related method of claim 1 , wherein the coarse alert area information indicates centre coordinates and a radius of the first PWS area.

3. The alert communication-related method of claim 1 , wherein the coarse alert area information identifies the first PWS area as a subdivision of the NTN cell, the subdivision being defined relative to a reference location of the NTN cell.

4. The alert communication-related method of claim 3, further comprising: receiving a subdivision configuration message defining at least two subdivision areas within the NTN cell.

5. The alert communication-related method of claim 4, wherein the first PWS area is identified using a bitmap corresponding to the at least two subdivision areas.

6. The alert communication-related method of any of claims 1 to 5, wherein the first message is a Paging message as defined in 3GPP technical specifications, aAttorney Docket No.: 0683-121 -WOcontrol message transmitted on a physical downlink control channel, PDCCH, or a system information block, SIB, defined in the 3GPP technical specifications.

7. The alert communication-related method of any of claims 1 to 6, further comprising:obtaining the current UE position from a global navigation satellite system, GNSS, module.

8. The alert communication-related method of any of claims 1 to 7, wherein: the first message includes a second PWS indication and the coarse alert area information indicates a second PWS area within the NTN cell,the determining includes determining whether the UE is in the second PWS area based on the current UE position and the coarse alert area information, andthe selectively acquiring includes acquiring the second message that further includes second alert details, including second alert content and second alert geofencing information, associated with the second PWS indication when the UE is in the second PWS area.

9. An alert communication-related method (2100) performed by a base station, BS, (104) configured to serve at least one user equipment, UE, (102) located in a non-terrestrial network, NTN, cell, the method comprising:receiving (1670) a first network public warning system, PWS, message including a first alert content and first geo-fencing information indicating a first alert area within the NTN cell;generating (2174), based on the first geo-fencing information, coarse alert area information indicating a first PWS area geographically covering the first alert area; transmitting (2144), to a UE in the NTN cell, a first message including a first PWS indication and the coarse alert area information; andtransmitting (2159), to the UE, a second message with first alert content associated with the first PWS indication and including the first geo-fencing information.Attorney Docket No.: 0683-121 -WO10. The alert communication-related method of claim 9, wherein the coarse alert area information indicates centre location coordinates and a radius for the first PWS area.

11. The alert communication-related method of claim 9, wherein the coarse alert area information identifies the first PWS area as a subdivision of the NTN cell defined relative to a reference location of the NTN cell.

12. The method of claim 11 , further comprising:transmitting a subdivision configuration message defining at least two subdivision areas within the NTN cell.

13. The alert communication-related method of claim 12, wherein the first PWS area is identified using a bitmap corresponding to the at least two subdivision areas.

14. The alert communication-related method of any of claims 9 to 13, wherein the first message is a Paging message as defined in 3GPP technical specifications, a control message transmitted on a physical downlink control channel, PDCCH, or a system information block, SIB, defined in the 3GPP technical specifications.

15. An alert communication-related method (1600) performed by a base station, BS, (104) configured to serve at least one user equipment, UE, (102) located in a non-terrestrial network, NTN, cell, the method comprising:receiving (1670), from a network core, a public warning system, PWS, message including geo-fencing information indicating an alert area geographically overlapping with the NTN cell;identifying (1672) among satellite beams covering the NTN cell, at least one satellite beam covering the alert area; andAttorney Docket No.: 0683-121 -WOtransmitting (1644) a PWS-related message using the at least one satellite beam while refraining from transmitting the PWS-related message with at least one other satellite beam covering another area than the alert area in the NTN cell.

16. A wireless communication device (102, 104) comprising a processor (152, 132) and a transceiver (154, 156, 134, 136) configured to cooperatively execute the methods of claims 1 to 15.

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