Public warning system (PWS) reception by aerial user equipment (UE)
Embodiments include methods for a user equipment (UE) configured to receive public warning system (PWS) messages from a radio access network (RAN) comprising a plurality of cells. Such methods include receiving, via a first cell having a first ground coverage and a first aerial coverage, a PWS message having a relevant area within a second ground coverage of a second cell but not within the first ground coverage. Such methods include determining whether the PWS message is applicable to the UE based on a first indication of the relevant area, a second indication of relevant altitudes for the PWS message, a third indication of applicability of the PWS message to aerial UEs, and/or a type of signaling by which the PWS message is received. Other embodiments include complementary methods for RAN nodes and core network (CN) nodes, as well as UEs and network nodes configured to perform such methods.
1 . A method for a user equipment (UE) configured to receive public warning system (PWS) messages from a radio access network (RAN) comprising a plurality of cells, the method comprising:
receiving, via a first cell having a first ground coverage and a first aerial coverage, a PWS message having a relevant area within a second ground coverage of a second cell but not within the first ground coverage; and
determining whether the PWS message is applicable to the UE based on a first indication of the relevant area and on one or more of the following:
a second indication of relevant altitudes for the PWS message, and
a third indication of applicability of the PWS message to aerial UEs,
wherein the first indication comprises one or more indices of respective one or more beams having coverage areas that overlap with the relevant area, and determining whether the PWS message is applicable to the UE comprises:
determining that the PWS message is applicable to the UE when the PWS message is received via a beam having one of the indices comprising the first indication; and
determining that the PWS message is not applicable to the UE when the PWS message is received via a beam having an index other than the indices comprising the first indication.
2 . The method of claim 1 , wherein:
the third indication indicates that the PWS message is applicable to aerial UEs based on one of the following: being included in the PWS message, or having a particular value in the PWS message; and
when the third indication indicates that the PWS message is applicable to aerial UEs, determining whether the PWS message is applicable to the UE is further based on one of the following: the UE's capability as an aerial UE, or the UE's current operation as an aerial UE.
3 . The method of claim 1 , wherein:
the second indication comprises one of the following: an altitude threshold, or one or more altitude ranges; and
when the second indication is included in the PWS message, determining whether the PWS message is applicable to the UE comprises:
determining the UE's current altitude;
determining that the PWS message is applicable to the UE when the current altitude meets a condition related to the second indication; and
determining that the PWS message is not applicable to the UE when the current altitude does not meet the condition related to the second indication,
wherein the condition related to the second indication is one of the following: less than the altitude threshold, greater than the altitude threshold, within a particular one of the altitude ranges, or within any of the altitude ranges.
4 . The method of claim 3 , wherein determining whether the PWS message is applicable to the UE further comprises determining that PWS message is applicable to the UE based on either of the following: the second indication is not included in the PWS message, or inability to determine the UE's current altitude.
5 . A method for a radio access network (RAN) node to provide public warning system (PWS) messages to user equipment (UEs), the method comprising:
transmitting a PWS message via a first cell of the RAN, wherein:
the first cell has a first ground coverage and a first aerial coverage;
the PWS message has a relevant area within a second ground coverage of a second cell of the RAN, but not within the first ground coverage;
the PWS message indicates applicability to receiving UEs based on a first indication of the relevant area and on one or more of the following:
a second indication of relevant altitudes for the PWS message, and
a third indication of applicability of the PWS message to aerial UEs;
the first indication comprises one or more indices of respective one or more beams having coverage areas that overlap with the relevant area; and
the first indication indicates that the PWS message is applicable to each particular UE based on the particular UE receiving the PWS message via a beam having one of the indices.
6 . The method of claim 5 , wherein:
the third indication indicates that the PWS message is applicable to aerial UEs based on one of the following: being included in the PWS message, or having a particular value in the PWS message; and
the third indication further indicates whether the PWS message is applicable to each particular UE that receives the PWS message, based on one of the following: the particular UE's capability as an aerial UE, or the particular UE's current operation as an aerial UE.
7 . The method of claim 5 , wherein:
the second indication comprises one of the following: an altitude threshold, or one or more altitude ranges; and
when the second indication is included in the PWS message, the second indication further indicates that the PWS message is applicable to each particular UE that receives the PWS message based on the particular UE's current altitude meeting a condition related to the second indication, wherein the condition is one of the following: less than the altitude threshold, greater than the altitude threshold, within a particular one of the altitude ranges, or within any of the altitude ranges.
8 . The method of claim 7 , wherein exclusion of the second indication from the PWS message indicates that the PWS message is applicable to all UEs that receive the PWS message.
9 . The method of claim 5 , wherein:
the method further comprises receiving flight path information for an aerial UE from an Unmanned Aircraft Systems Traffic Management (UTM) system;
the flight path information includes at least one location in the first aerial coverage and a corresponding time; and
the PWS message is transmitted to the aerial UE via unicast signaling at approximately the corresponding time.
10 . The method of claim 5 , further comprising receiving the PWS message from a node or function of a core network (CN) coupled to the RAN.
11 . A method for a core network (CN) node to provide public warning system (PWS) messages to user equipment (UEs) via a radio access network (RAN), the method comprising:
determining a relevant area for an incident, wherein the relevant area is within a second ground coverage of a second cell of the RAN;
determining one or more additional cells of the RAN that have respective ground coverage areas proximate to the relevant area, wherein the additional cells include a first cell that has a first ground coverage area and a first aerial coverage area; and
sending a PWS message, pertaining to the incident, to one or more RAN nodes for transmission to UEs via the second cell and the one or more additional cells, wherein:
the PWS message indicates applicability to receiving UEs based on a first indication of the relevant area and on one or more of the following: a second indication of relevant altitudes for the PWS message, and a third indication of applicability of the PWS message to aerial UEs;
the first indication comprises one or more indices of respective one or more beams having coverage areas that overlap with the relevant area; and
the first indication indicates that the PWS message is applicable to each particular UE based on the particular UE receiving the PWS message via a beam having one of the indices.
12 . The method of claim 11 , wherein:
the third indication indicates that the PWS message is applicable to aerial UEs based on one of the following: being included in the PWS message, or having a particular value in the PWS message; and
the third indication further indicates whether the PWS message is applicable to each particular UE that receives the PWS message, based on one of the following: the particular UE's capability as an aerial UE, or the particular UE's current operation as an aerial UE.
13 . The method of claim 11 , wherein:
the second indication comprises one of the following: an altitude threshold, or one or more altitude ranges;
when the second indication is included in the PWS message, the second indication further indicates that the PWS message is applicable to each particular UE that receives the PWS message based on the particular UE's current altitude meeting a condition related to the second indication; and
the condition related to the second indication is one of the following: less than the altitude threshold, greater than the altitude threshold, within a particular one of the altitude ranges, or within any of the altitude ranges.
14 . The method of claim 13 , wherein exclusion of the second indication from the PWS message indicates that the PWS message is applicable to all UEs that receive the PWS message.
15 . A user equipment (UE) comprising communication interface and processing circuitry that are operatively coupled and are configured to perform the method of claim 1 .
16 . A radio access network (RAN) node comprising communication interface circuitry and processing circuitry that are operatively coupled and are configured to perform the method of claim 5 .
17 . A core network (CN) node comprising communication interface circuitry and processing circuitry that are operatively coupled and are configured to perform the method of claim 11 .