WO2020244786A1

WO2020244786A1 - Defining warning areas in emergency situations

Info

Publication number: WO2020244786A1
Application number: PCT/EP2019/068902
Authority: WO
Inventors: Zeki BILGIN; Mehmet Akif ERSOY
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2019-06-06
Filing date: 2019-07-12
Publication date: 2020-12-10

Abstract

There is provided a method performed by a node of a network. The method comprises acquiring (102) coordinates that define a warning area having a first shape. The warning area comprises an area in which to warn users about an emergency situation. The method comprises approximating (104) the warning area to a second shape based on the acquired coordinates. The second shape is sized to completely enclose the first shape and is a simplified geometric shape compared to the first shape. The method comprises transmitting (106), towards one or more user equipments, parameters that define a perimeter of the second shape.

Description

DEFINING WARNING AREAS IN EMERGENCY SITUATIONS

Technical Field

The disclosure relates to methods for defining warning areas in emergency situations and a node and user equipment configured to operate in accordance with the methods.

Background

The third generation partnership project (3GPP) standard TS 123 041 describes a cell broadcast short message service (CBS) for the global system for mobile communications (GSM), the universal mobile telecommunications system (UMTS), and the public warning system (PWS) for GSM in the second-generation (2G) of wireless mobile telecommunications technology, UMTS in the third-generation (3G) of wireless mobile telecommunications technology, the evolved universal mobile telecommunications service terrestrial radio access network (E-UTRAN) in the fourth- generation (4G) of wireless mobile telecommunications technology, and the next generation radio access network (NG-RAN) in the fifth-generation (5G) of wireless mobile telecommunications technology. According to this standard, CBS messages including warning messages are sent to multiple subscribers in a specified geographical area at the same time. The purpose of sending warning messages is to notify users about an emergency situation, such as earthquake, tsunami etc.

PWS enables the distribution of warning messages on behalf of a public authority. The 3GPP standard TS 123 041 describes a warning message delivery procedure for 2G, 3G, 4G and 5G. In this procedure, a user equipment (UE) determines whether it is inside or outside warning area coordinates. The UE makes this determination through computational geometry and, specifically, by using a point-in-polygon (PI P) algorithm. There are several existing PI P algorithms that can be used of which a person skilled in the art will be aware including, for example, a ray casting algorithm, a grid algorithm, a sum of angle algorithm, a swath algorithm, a sign of offset algorithm, a sum of area algorithm, an orientation algorithm, and a wedge algorithm. However, regardless of which of these existing PIP algorithms is adopted, there is a heavy computational burden on the UE to run the algorithm. According to the 3GPP standard TS 123 041 , whenever a UE receives a CBS warning message containing warning area coordinates, it performs computations to determine if it is inside or outside the warning area defined by the warning area coordinates in the warning message. The warning area coordinates are determined by the cell broadcast centre (CBC) for E-UTRAN (4G) and by the cell broadcast centre function (CBCF) for NG-RAN (5G) based on operator policy. However, there currently exist several problems.

One problem is that there is no regulation or definition in the standard regarding the manner in which warning area coordinates are selected to identify a region of interest. As such, there is no certainty in the number of geographical coordinates that will be determined. The lack of specification regarding the determination of warning area coordinates in warning message delivery procedures results in user equipments (UEs) having to employ computationally inefficient or expensive algorithms to determine whether they are inside or outside a warning area. More specifically, since the warning area coordinates are not determined by certain pre specified rules, there is uncertainty and thus ambiguities occur. This makes it difficult to develop and restricts the design of an efficient algorithm for UEs to employ to determine whether they are inside or outside a region of interest.

While there are some algorithms developed for this purpose, the computational complexity of these algorithms depends on the size of the input (i.e. the number of coordinates provided). Moreover, one algorithm may perform better with a smaller number of coordinates defining an area, whereas another algorithm may perform better with a larger number of coordinates. Since the manner in which to determine warning area coordinates is not specified, the result is usually that non-optimized general-purpose algorithms are implemented on UEs, which means that performance is often suboptimal.

Thus, in summary, there exist algorithms aimed at solving the issues with the PI P algorithms. However, all of these existing algorithms result in an additional computational burden on UEs. Moreover, the complexity of the computation is still dependent on both the algorithm that is implemented and the input of that algorithm (i.e. the warning area coordinates). As such, there is a need for an improved technique, which is aimed at addressing the problems of existing algorithms. Summary

It is thus an object to obviate or eliminate at least some of the above disadvantages associated with existing techniques and provide a technique for defining a warning area in an emergency situation.

Therefore, according to an aspect, there is provided a method performed by a node of a network. The method comprisesacquiring coordinates that define a warning area having a first shape. The warning area comprises an area in which to warn users about an emergency situation. The method comprises approximating the warning area to a second shape based on the acquired coordinates. The second shape is sized to completely enclose the first shape and is a simplified geometric shape compared to the first shape. The method comprises transmitting, towards one or more user equipments (UEs), parameters that define a perimeter of the second shape.

The idea thus provides a technique for defining a warning area in an emergency situation. As the second shape is sized to completely enclose the first shape, there is no detrimental effect on warning users about an emergency situation since all UEs covered by the original warning area will still be covered by the newly approximated warning area. The newly approximated warning area advantageously covers the intended warning area completely. Moreover, as the warning area is approximated to a simplified geometric shape compared to the first shape, bandwidth can be conserved by the transmission of parameters that define a perimeter of the simplified geometric shape, rather than the transmission of the coordinates of the original more complex shape. For example, the size of warning messages that may include the parameters can be reduced, which can speed up the delivery of those warning messages. This can be useful given the strict delivery duration requirement for warning messages specified by the standard, especially during an emergency situation.

The fact that the warning area is approximated to a simplified geometric shape compared to the first shape also means that the computations a UE needs to perform in order to determine whether it is inside or outside the shape are less complex. Thus, the computations can be performed more easily, more efficiently, and with fewer resources. The previous ambiguity in the definition of the warning area is eliminated since the warning area is defined in a more precise manner (in particular, the warning area is approximated to a particular geometric shape), which means that it is possible to design less complex and less computationally heavy algorithms to be performed on UEs for the UEs to determine whether they are outside the warning area. This has the effect that energy is conserved, which can be particularly useful in the case of an emergency situation.

In some embodiments, the second shape may be a circle. In some of these embodiments, the parameters that define the perimeter of the second shape may comprise coordinates of a centre of the second shape and a radius of the second shape. Thus, the parameters that are transmitted comprise only coordinates of the centre of the second shape and the radius of the second shape, which makes the transmission more efficient and also conserves bandwidth.

In some embodiments, approximating the warning area to the second shape may comprise approximating the warning area to the second shape using a smallest-circle algorithm, such that the second shape contains all of the acquired coordinates. Alternatively, in some embodiments, approximating the warning area to the second shape may comprise approximating the warning area to a square or rectangle and approximating the warning area to the second shape, such that the centre of the second shape is the centre of the square or rectangle and the radius of the second shape is half of the distance between two diagonally opposite corners of the square or rectangle. In these ways, the warning area can be approximated to the second shape in a simple and efficient manner in order to conserve computational resources.

In some embodiments, the second shape may be a square or a rectangle. In some of these embodiments, the parameters that define the perimeter of the second shape may comprise coordinates of at least two diagonally opposite corners of the second shape or coordinates of at least three corners of the second shape. Thus, the parameters that are transmitted comprise only the minimum number of coordinates necessary for a UE to determine whether it is inside or outside the second shape, which makes the transmission more efficient and also conserves bandwidth.

In some embodiments, approximating the warning area to the second shape may comprise identifying an outermost one of the acquired coordinates in each of four cardinal directions and approximating the warning area to the second shape, such that each side of the second shape passes through a different identified outermost one of the acquired coordinates. In this way, the warning area can be approximated to the second shape in a simple and efficient manner in order to conserve computational resources.

In some embodiments, the acquired coordinates may be coordinates of a coordinate system having two perpendicular coordinate axes and the warning area may be approximated to the second shape, such that two sides of the second shape are parallel to one of the two perpendicular coordinate axes and another two sides of the second shape are parallel to the other one of the two perpendicular coordinate axes. In this way, the computations that a UE needs to perform to determine whether it is inside or outside the warning area can be simplified even further to ease the computational burden on the UE and make the computations even more efficient.

According to another aspect of the idea, there is provided a node configured to operate in accordance with the method described earlier in respect of the node. In some embodiments, the node may comprise processing circuitry and at least one memory for storing instructions which, when executed by the processing circuitry, cause the node to operate in accordance with the method described earlier in respect of the node. The node thus provides the advantages discussed earlier in respect of the method performed by the node.

According to another aspect of the idea, there is provided a method performed by a user equipment (UE) of a network. The method comprises receiving parameters that define a perimeter of a second shape to which a warning area having a first shape is approximated. The warning area comprises an area in which to warn users about an emergency situation and the second shape is sized to completely enclose the first shape and is a simplified geometric shape compared to the first shape. The method comprises determining whether a location of the UE is inside or outside the second shape based on the received parameters.

The fact that the warning area is approximated to a simplified geometric shape compared to the first shape means that the computations a UE needs to perform in order to determine whether it is inside or outside the shape are less complex. Thus, the computations can be performed more easily, more efficiently, and with fewer resources. The previous ambiguity in the definition of the warning area is eliminated since the warning area is defined in a more precise manner (in particular, the warning area is approximated to a particular geometric shape), which means that the UE can employ less complex and less computationally heavy algorithms to determine whether they are outside the warning area. The UE can easily determine whether they are inside or outside the approximated area without performing heavy computations. The computational burden on the UE is minimized. This provides energy efficiency for the UE, which is especially important in the case of an emergency situation. Even UEs outside the warning area can benefit from these improvements as they are not aware that they are outside the warning area until they perform computations to compute this and these computations can now be performed more easily, more efficiently, and with fewer resources.

In some embodiments, the second shape may be a circle. In some of these embodiments, the parameters that define the perimeter of the second shape may comprise coordinates of a centre of the second shape and a radius of the second shape. Thus, the parameters that are received comprise only coordinates of the centre of the second shape and the radius of the second shape, which makes the transmission more efficient and also conserves bandwidth.

In some embodiments, determining whether a location of the UE is inside or outside the second shape may comprise comparing a distance from the location of the UE to the centre of the second shape to the radius of the second shape. In some embodiments, if the distance from the location of the UE to the centre of the second shape is less than or equal to the radius of the second shape, it may be determined that the location of the UE is inside the second shape. In some embodiments, if the distance from the location of the UE to the centre of the second shape is greater than the radius of the second shape, it may be determined that the location of the UE is outside the second shape. In some embodiments, the distance from the location of the UE to the centre of the second shape may comprise a Euclidean distance. In this way, the UE can determine whether it is inside or outside the second shape in a simple and efficient manner with only a minimum number of comparisons in order to conserve computational resources.

In some embodiments, the second shape may be a square or a rectangle. In some of these embodiments, the parameters that define the perimeter of the second shape may comprise reference coordinates, wherein the reference coordinates may comprise coordinates of at least two diagonally opposite corners of the second shape or coordinates of at least three corners of the second shape. Thus, the parameters that are received comprise only the minimum number of coordinates necessary for a UE to determine whether it is inside or outside the second shape, which makes the transmission more efficient and also conserves bandwidth.

In some embodiments, determining whether a location of the UE is inside or outside the second shape may comprise comparing coordinates of the location of the UE to the reference coordinates. In some embodiments, if an x-coordinate of the location of the UE is between a smallest x-coordinate of the reference coordinates and a largest x- coordinate of the reference coordinates and a y-coordinate of the location of the UE is between a smallest y-coordinate of the reference coordinates and a largest y- coordinate of the reference coordinates, determining that the location of the UE is inside the second shape. Alternatively, in some embodiments, if an x-coordinate of the location of the UE is less than a smallest x-coordinate of the reference coordinates, an x-coordinate of the location of the UE is greater than a largest x-coordinate of the reference coordinates, a y-coordinate of the location of the UE is less than a smallest y-coordinate of the reference coordinates, or a y-coordinate of the location of the UE is greater than a largest y-coordinate of the reference coordinates, determining that the location of the UE is outside the second shape. In these ways, the UE can determine whether it is inside or outside the second shape in a simple and efficient manner with only a minimum number of comparisons in order to conserve computational resources.

In some embodiments, the method may comprise, if the location of the UE is determined to be inside the second shape, initiating an indication to warn a user of the UE about an emergency situation. Thus, the relevant users can be warned about an emergency situation in the most efficient manner.

According to another aspect of the idea, there is provided a UE configured to operate in accordance with the method described earlier in respect of the UE. In some embodiments, the UE may comprise processing circuitry and at least one memory for storing instructions which, when executed by the processing circuitry, cause the UE to operate in accordance with the method described earlier in respect of the UE. The UE thus provides the advantages discussed earlier in respect of the method performed by the UE.

According to another aspect of the idea, there is provided a system comprising at least one node as described earlier and at least one UE as described earlier. The system thus provides the advantages discussed earlier in respect of the method performed by the node and the UE. Also, since warning messages are broadcast at repeated intervals, any warning messages comprising the parameters defining the perimeter of the second shape will have an advantageous effect on the overall performance of the system. For example, there may be a large number of UEs receiving warning messages and performing computations to determine whether they are inside or outside the second shape, which means that the accumulated energy improvements in the system can be considerable.

According to another aspect of the idea, there is provided a computer program comprising instructions which, when executed by processing circuitry, cause the processing circuitry to perform the method described earlier. The computer program thus provides the advantages discussed earlier in respect of the method performed by the node and the UE.

According to another aspect of the idea, there is provided a computer program product, embodied on a non-transitory machine-readable medium, comprising instructions which are executable by processing circuitry to cause the processing circuitry to perform the method described earlier. The computer program product thus provides the advantages discussed earlier in respect of the method performed by the node and the UE.

Therefore, an advantageous technique for defining a warning area in an emergency situation is provided.

Brief description of the drawings

For a better understanding of the idea, and to show how it may be put into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a block diagram illustrating a node according to an embodiment;

Figure 2 is a block diagram illustrating a method performed by a node according to an embodiment;

Figure 3 is a block diagram illustrating a user equipment according to an embodiment;

Figure 4 is a block diagram illustrating a method performed by a user equipment according to an embodiment;

Figure 5 is a signalling diagram illustrating an exchange of signals in an embodiment;

Figure 6 is a simplified schematic of a warning area according to an embodiment;

Figure 7 is a simplified schematic of a warning area according to an embodiment;

Figure 8 is a simplified schematic of a warning area according to an embodiment; Figure 9 is a simplified schematic of a warning area according to an embodiment;

Figure 10 is a block diagram illustrating a node according to an embodiment; and

Figure 11 is a block diagram illustrating a user equipment according to an embodiment.

Detailed Description

Figure 1 illustrates a node 10 in accordance with an embodiment. The node 10 is for defining a warning area. A warning area comprises an area in which to warn users about an emergency situation. The node 10 is a node of a network. The network can be any network including, but not limited to, a second generation (2G) network, a third generation (3G) network, a fourth generation (4G) network, a fifth generation (5G) network, or any other generation network. As illustrated in Figure 1 , the node 10 comprises processing circuitry (or logic) 12. The processing circuitry 12 controls the operation of the node 10 and can implement the method described herein in respect to the node 10. The processing circuitry 12 can comprise one or more processors, processing units, multi-core processors or modules that are configured or programmed to control the node 10 in the manner described herein. In particular implementations, the processing circuitry 12 can comprise a plurality of software and/or hardware modules that are each configured to perform, or are for performing, individual or multiple steps of the method described herein.

Briefly, the processing circuitry 12 of the node 10 is configured to acquire coordinates that define a warning area having a first shape. The processing circuitry 12 of the node 10 is configured to approximate the warning area to a second shape based on the acquired coordinates. The second shape is sized to completely enclose the first shape and is a simplified geometric shape compared to the first shape. The processing circuitry 12 of the node 10 is configured to transmit, towards one or more user equipments (UEs), parameters that define a perimeter of the second shape.

As illustrated in Figure 1 , the node 10 may optionally comprise a memory 14. The memory 14 of the node 10 can comprise a volatile memory or a non-volatile memory. In some embodiments, the memory 14 of the node 10 may comprise a non-transitory media. Examples of the memory 14 of the node 10 include, but are not limited to, a random access memory (RAM), a read only memory (ROM), a mass storage media such as a hard disk, a removable storage media such as a compact disk (CD) or a digital video disk (DVD), and/or any other memory.

The processing circuitry 12 of the node 10 can be connected to the memory 14 of the node 10. In some embodiments, the memory 14 of the node 10 may be for storing program code or instructions which, when executed by the processing circuitry 12 of the node 10, cause the node 10 to operate in the manner described herein in respect of the node 10. For example, in some embodiments, the memory 14 of the node 10 may be configured to store program code or instructions that can be executed by the processing circuitry 12 of the node 10 to perform the method described herein in respect of the node 10. Alternatively or in addition, the memory 14 of the node 10 can be configured to store any parameters, requests, responses, indications, information, data, notifications, signals, or similar, that are described herein. The processing circuitry 12 of the node 10 may be configured to control the memory 14 of the node 10 to store any parameters, requests, responses, indications, information, data, notifications, signals, or similar, that are described herein.

In some embodiments, as illustrated in Figure 1 , the node 10 may optionally comprise a communications interface 16. The communications interface 16 of the node 10 can be connected to the processing circuitry 12 of the node 10 and/or the memory 14 of node 10. The communications interface 16 of the node 10 may be operable to allow the processing circuitry 12 of the node 10 to communicate with the memory 14 of the node 10 and/or vice versa. The communications interface 16 of the node 10 can be configured to transmit and/or receive any parameters, requests, responses, indications, information, data, notifications, signals, or similar, that are described herein. In some embodiments, the processing circuitry 12 of the node 10 may be configured to control the communications interface 16 of the node 10 to transmit and/or receive any parameters, requests, responses, indications, information, data, notifications, signals, or similar, that are described herein.

Although the node 10 is illustrated in Figure 1 as comprising a single memory 14, it will be appreciated that the node 10 may comprise at least one memory (i.e. a single memory or a plurality of memories) 14 that operate in the manner described herein. Similarly, although the node 10 is illustrated in Figure 1 as comprising a single communications interface 16, it will be appreciated that the node 10 may comprise at least one communications interface (i.e. a single communications interface or a plurality of communications interface) 16 that operate in the manner described herein.

It will also be appreciated that Figure 1 only shows the components required to illustrate an embodiment of the node 10 and, in practical implementations, the node 10 may comprise additional or alternative components to those shown.

Figure 2 is a flowchart illustrating a method performed by a node in accordance with an embodiment. The method is for defining a warning area. As mentioned earlier, a warning area comprises an area in which to warn users about an emergency situation.

The node 10 described earlier with reference to Figure 1 is configured to operate in accordance with the method of Figure 2. The method can be performed by or under the control of the processing circuitry 12 of the node 10. As mentioned earlier, the node 10 is a node of a network. The network can be any network including, but not limited to, a 2G network, a 3G network, a 4G network, a 5G network, or any other generation network.

With reference to Figure 2, at block 102, coordinates (e.g. geographic coordinates) that define a warning area having a first shape are acquired. More specifically, the processing circuitry 12 of the node 10 acquires coordinates that define a warning area having a first shape. The coordinates may also be referred to herein as warning area coordinates. In some embodiments, each side of the first shape may comprise a line joining two of the acquired coordinates. The first shape can be any form of polygon, such as a convex polygon, a concave polygon, an irregular polygon, etc. The acquired coordinates define a perimeter of the first shape.

Although not illustrated in Figure 2, in some embodiments, a request to broadcast a warning message may be received by the node 10 or, more specifically, by the processing circuitry 12 of the node 10 (e.g. via the communications interface 16 of the node 10). In some of these embodiments, the request may comprises the coordinates that define the warning area having a first shape and the processing circuitry 12 of the node 10 may be configured to identify the coordinates in the received request. Thus, in some embodiments, the coordinates may be acquired by the processing circuitry 12 of the node 10 in this way. That is, the coordinates may be acquired from a warning message according to some embodiments.

At block 104 of Figure 2, the warning area is approximated to a second shape based on the acquired coordinates. More specifically, the processing circuitry 12 of the node 10 approximates the warning area to a second shape based on the acquired coordinates. The second shape is sized to completely enclose (e.g. the acquired coordinates of the warning area having) the first shape and is a simplified geometric shape compared to the first shape. The second shape thus has a particular geometric relationship to the first shape, which means that any computations performed by a UE to determine whether they are inside or outside the second shape will be more straightforward and efficient. The second shape can, for example, be a circle, a square or a rectangle. The second shape is an imaginary shape. The shape can be the minimal shape needed to completely enclose (e.g. the acquired coordinates of the warning area having) the first shape.

In some embodiments where the second shape is a square or a rectangle, the parameters that define the perimeter of the second shape can comprise coordinates of at least two diagonally opposite corners of the second shape. Alternatively, in some embodiments where the second shape is a square or a rectangle, the parameters that define the perimeter of the second shape can comprise coordinates of at least three corners of the second shape. In some of these embodiments, the parameters that define the perimeter of the second shape can comprise coordinates (an x-coordinate and a y-coordinate) of a first corner of the second shape, only an x-coordinate of a second corner of the second shape and only a y-coordinate of a third corner of the second shape, where the first, second and third corners are different. In other embodiments, the parameters that define the perimeter of the second shape may comprise all four coordinates of the second shape. Thus, in this example, the parameters are (corner) coordinates of the second shape 502. The warning area is in effect defined using new coordinates.

In some embodiments where the second shape is a square or a rectangle, the warning area may be approximated to the second shape by identifying an outermost one of the acquired coordinates in each of four cardinal directions (i.e. north, south, east and west) and approximating the warning area to the second shape, such that each side of the second shape passes through a different identified outermost one of the acquired coordinates. In some embodiments, where the acquired coordinates are coordinates of a coordinate system having two perpendicular coordinate axes, the warning area may be approximated to the second shape, such that two sides of the second shape are parallel to one of the two perpendicular coordinate axes and another two sides of the second shape are parallel to the other one of the two perpendicular coordinate axes. Thus, in embodiments where the second shape is a square or rectangle, the second shape can comprise straight sides. In this way, computations for UEs to determine whether they are inside or outside the second shape can be reduced further. In some embodiments where the acquired coordinates are coordinates of a coordinate system having two perpendicular coordinate axes, lines of latitude (parallels) and lines of longitude (meridians) may be the two perpendicular axes of such a coordinate system as in geographical coordinate systems. In embodiments where the second shape is a circle, the parameters that define the perimeter of the second shape can comprise coordinates of a centre of the second shape and a radius of the second shape. In some of these embodiments, the warning area may be approximated to the second shape by approximating the warning area to the second shape using a smallest-circle algorithm, such that the second shape contains (or covers) all of the acquired coordinates. Thus, according to some embodiments, a smallest-circle algorithm may be used to find a minimum (or smallest) circle that contains (or covers) all of the acquired coordinates and this minimum (or smallest) circle is the second shape. A person skilled in the art will be aware of various smallest-circle algorithms that can be used.

In another of these embodiments, the warning area may be approximated to the second shape by initially approximating the warning area to a square or rectangle (e.g. in the manner described earlier) and approximating the warning area to the second shape, such that the centre of the second shape is the centre of the square or rectangle and the radius of the second shape is half of the distance between two diagonally opposite corners of the square or rectangle. The centre of the square or rectangle is a point at which a line from two pairs of diagonally opposite corners of the square or rectangle meet. Thus, in some embodiments, the square or rectangle can be converted into a circle, which is centred at the centre of the square or rectangle with a diameter equal to a diagonal of the square or rectangle.

In some embodiments, the processing circuitry 12 of the node 10 may be configured to determine a shape (e.g. circle, rectangle or square) to select for the second shape. For example, in some embodiments, the processing circuitry 12 of the node 10 may be configured to approximate the warning area to any two or more shapes (e.g. two or more of a circle, rectangle and square in the manner described earlier) and select one of the two or more shapes as the second shape. In some of these embodiments, the smallest of the two or more shapes may be selected as the second shape, e.g. the shape that has the smallest area may be selected as the second shape. This can ensure that the second shape has an optimum size. For example, if the perimeter of the warning area having the first shape extends over a long, narrow region, then it may be more feasible to approximate the first shape to a rectangle as the second shape because approximating the first shape to a circle as the second shape may yield an unnecessarily large area in this case. On contrary, if the perimeter of the warning area having the first shape extends similar distances in both a vertical direction and a horizontal direction, then it may be more feasible to approximate the first shape to a circle as the second shape.

Returning back to Figure 2, at block 106, parameters that define the perimeter of the second shape are transmitted towards one or more UEs. More specifically, the processing circuitry 12 of the node 10 transmits (e.g. via a communications interface 16 of the node 10) parameters that define a perimeter of the second shape towards one or more UEs. In some embodiments, the processing circuitry 12 of the node 10 can be configured to determine the parameters that are transmitted.

Thus, it is possible to identify a warning area approximately, such as by only two (diagonally opposite), three, or four coordinates representing corners of a rectangle or by only a centre and radius of a circle. The benefit of this transformation is that the specific computations that UEs need to perform in order to determine whether they are inside or outside the warning area is computationally less complex and thus energy improvements can be achieved, which is particularly useful during an emergency situation. Also, as there may be a large number of UEs receiving warning messages and performing such computations, the accumulated energy improvements can be considerable. Moreover, as a warning area is usually defined loosely, i.e. there is no strict boundary framing the warning area, there is no detrimental effect to approximating the warning area in the manner described herein. For example, in the case of flooding, it is normally impossible to set a strict border for the affected area. A significant amount of energy improvements can be obtained on many UEs in the warning area, without compromising safety.

Figure 3 illustrates a user equipment (UE) 20 in accordance with an embodiment. The UE 20 is for determining whether a location of the UE 20 is inside or outside a warning area. As mentioned earlier, a warning area comprises an area in which to warn users about an emergency situation. The UE 20 is a UE of a network. The network can be any network including, but not limited to, 2G network, a 3G network, a 4G network, a 5G network, or any other generation network.

As illustrated in Figure 3, the UE 20 comprises processing circuitry (or logic) 22. The processing circuitry 22 controls the operation of the UE 20 and can implement the method described herein in respect to the UE 20. The processing circuitry 22 can comprise one or more processors, processing units, multi-core processors or modules that are configured or programmed to control the UE 20 in the manner described herein. In particular implementations, the processing circuitry 22 can comprise a plurality of software and/or hardware modules that are each configured to perform, or are for performing, individual or multiple steps of the method described herein.

Briefly, the processing circuitry 22 of the UE 20 is configured to receive parameters that define a perimeter of a second shape to which a warning area having a first shape is approximated. The second shape is sized to completely enclose the first shape and is a simplified geometric shape compared to the first shape. The processing circuitry 22 of the UE 20 is configured to determine whether the UE is inside or outside the second shape based on the received parameters.

As illustrated in Figure 3, the UE 20 may optionally comprise a memory 24. The memory 24 of the UE 20 can comprise a volatile memory or a non-volatile memory. In some embodiments, the memory 24 of the UE 20 may comprise a non-transitory media. Examples of the memory 24 of the UE 20 include, but are not limited to, a random access memory (RAM), a read only memory (ROM), a mass storage media such as a hard disk, a removable storage media such as a compact disk (CD) or a digital video disk (DVD), and/or any other memory.

The processing circuitry 22 of the UE 20 can be connected to the memory 24 of the UE 20. In some embodiments, the memory 24 of the UE 20 may be for storing program code or instructions which, when executed by the processing circuitry 22 of the UE 20, cause the UE 20 to operate in the manner described herein in respect of the UE 20. For example, in some embodiments, the memory 24 of the UE 20 may be configured to store program code or instructions that can be executed by the processing circuitry 22 of the UE 20 to perform the method described herein in respect of the UE 20.

Alternatively or in addition, the memory 24 of the UE 20 can be configured to store any parameters, requests, responses, indications, information, data, notifications, signals, or similar, that are described herein. The processing circuitry 22 of the UE 20 may be configured to control the memory 24 of the UE 20 to store any parameters, requests, responses, indications, information, data, notifications, signals, or similar, that are described herein.

In some embodiments, as illustrated in Figure 3, the UE 20 may optionally comprise a communications interface 26. The communications interface 26 of the UE 20 can be connected to the processing circuitry 22 of the UE 20 and/or the memory 24 of UE 20. The communications interface 26 of the UE 20 may be operable to allow the processing circuitry 22 of the UE 20 to communicate with the memory 24 of the UE 20 and/or vice versa. The communications interface 26 of the UE 20 can be configured to transmit and/or receive any parameters, requests, responses, indications, information, data, notifications, signals, or similar, that are described herein. In some embodiments, the processing circuitry 22 of the UE 20 may be configured to control the communications interface 26 of the UE 20 to transmit and/or receive any parameters, requests, responses, indications, information, data, notifications, signals, or similar, that are described herein.

Although the UE 20 is illustrated in Figure 3 as comprising a single memory 24, it will be appreciated that the UE 20 may comprise at least one memory (i.e. a single memory or a plurality of memories) 24 that operate in the manner described herein. Similarly, although the UE 20 is illustrated in Figure 3 as comprising a single communications interface 26, it will be appreciated that the UE 20 may comprise at least one communications interface (i.e. a single communications interface or a plurality of communications interface) 26 that operate in the manner described herein.

It will also be appreciated that Figure 3 only shows the components required to illustrate an embodiment of the UE 20 and, in practical implementations, the UE 20 may comprise additional or alternative components to those shown.

Figure 4 is a flowchart illustrating a method of performed by a UE in accordance with an embodiment. The method is for determining whether the UE is inside or outside a warning area. As mentioned earlier, a warning area comprises an area in which to warn users about an emergency situation.

The UE 20 described earlier with reference to Figure 3 is configured to operate in accordance with the method of Figure 4. The method can be performed by or under the control of the processing circuitry 22 of the UE 20. As mentioned earlier, the UE 20 is a UE of a network. The network can be any network including, but not limited to, a 2G network, a 3G network, a 4G network, a 5G network, or any other generation network.

With reference to Figure 4, at block 202, parameters that define a perimeter of a second shape to which a warning area having a first shape is approximated are received. More specifically, the processing circuitry 22 of the UE 20 receives (e.g. via a communications interface 26 of the UE 20) parameters that define a perimeter of a second shape to which a warning area having a first shape is approximated. The second shape is sized to completely enclose the first shape and is a simplified geometric shape compared to the first shape. At block 204, it is determined whether a location of the UE is inside or outside the second shape based on the received parameters. More specifically, the processing circuitry 22 of the UE 20 determines whether the location of the UE is inside or outside the second shape based on the received parameters.

As described earlier, in some embodiments, the second shape may be a circle. In some of these embodiments, the parameters that define the perimeter of the second shape may comprise coordinates of a centre of the second shape and a radius of the second shape. In some embodiments where the second shape is a circle, determining whether a location of the UE 20 is inside or outside the second shape may comprise comparing a distance from the location of the UE 20 to the centre of the second shape to the radius of the second shape. More specifically, the processing circuitry 22 of the UE 20 may be configured to perform this comparison.

In some of these embodiments, if the distance from the location of the UE 20 to the centre of the second shape is less than or equal to the radius of the second shape, it may be determined that the location of the UE 20 is inside the second shape. More specifically, the processing circuitry 22 of the UE 20 may be configured to make this determination. Alternatively, in some of these embodiments, if the distance from the location of the UE 20 to the centre of the second shape is greater than the radius of the second shape, it may be determined that the location of the UE 20 is outside the second shape. More specifically, the processing circuitry 22 of the UE 20 may be configured to make this determination. In some embodiments, the distance from the location of the UE 20 to the centre of the second shape may comprise a Euclidean distance.

As also described earlier, in other embodiments, the second shape may be a square or a rectangle. In some of these embodiments, the parameters that define the perimeter of the second shape may comprise reference coordinates. The reference coordinates can comprise coordinates of at least two diagonally opposite corners of the second shape or coordinates of at least three corners of the second shape. In some embodiments where the second shape is a square or a rectangle, determining whether a location of the UE 20 is inside or outside the second shape may comprise comparing coordinates of the location of the UE 20 to the reference coordinates. More specifically, the processing circuitry 22 of the UE 20 may be configured to perform this comparison.

In some of these embodiments, if an x-coordinate of the location of the UE 20 is between a smallest x-coordinate of the reference coordinates and a largest x- coordinate of the reference coordinates and a y-coordinate of the location of the UE 20 is between a smallest y-coordinate of the reference coordinates and a largest y- coordinate of the reference coordinates, it may be determined that the location of the UE 20 is inside the second shape. Otherwise, it may be determined that the location of the UE 20 is outside the second shape. More specifically, the processing circuitry 22 of the UE 20 may be configured to make this determination. Alternatively, in some of these embodiments, if an x-coordinate of the location of the UE 20 is less than a smallest x-coordinate of the reference coordinates, an x-coordinate of the location of the UE 20 is greater than a largest x-coordinate of the reference coordinates, a y- coordinate of the location of the UE 20 is less than a smallest y-coordinate of the reference coordinates, or a y-coordinate of the location of the UE 20 is greater than a largest y-coordinate of the reference coordinates, it may be determined that the location of the UE 20 is outside the second shape. Otherwise, it may be determined that the location of the UE 20 is inside the second shape. More specifically, the processing circuitry 22 of the UE 20 may be configured to make this determination.

In some embodiments, the method may comprise, if the location of the UE 20 is determined to be inside the second shape, initiating an indication (e.g. an alert, a message, etc.) to warn a user of the UE 20 about an emergency situation. More specifically, the processing circuitry 22 of the UE 20 may be configured to initiate the indication if the location of the UE 20 is determined to be inside the second shape.

Figure 5 is a signalling (or call flow) diagram illustrating an exchange of signals in an example embodiment. The exchange of signals is in a network.

The network illustrated in this example is a 5G network or, more specifically, a next generation radio access network (NG-RAN). However, it will be understood that this is merely one of many examples of a network and, in other examples, the network can be any other generation (e.g. a 2G, a 3G, a 4G, etc.) network, e.g. an evolved universal mobile telecommunications service terrestrial radio access network (E-UTRAN) in 4G, and so on. With other generation networks, similar steps will be understood to apply.

The network comprises the node 10 described earlier and the UE 20 described earlier. The node 10 is as described earlier with reference to Figures 1 and 2 and the UE 20 is as described earlier with reference to Figures 3 and 4. For the purpose of this 5G example, the node 10 is a cell broadcast centre function (CBCF) node or a public warning system inter-working function (PWS-IWF) node. However, it will be understood that the node 10 may be an equivalent node in other generation networks, e.g. a cell broadcast centre (CBC) node in 4G and so on.

In the illustrated example embodiment of Figure 5, the network also comprises three other nodes 30, 40, 50. For the purpose of this 5G example, the other nodes 30, 40, 50 comprise a cell broadcast entity (CBE) node 30 (e.g. a regulator or any other information source), an access management functions (AMF) node 40, and an NG- RAN node 50. However, it will be understood that these other nodes may alternatively be equivalent nodes of any other generation network.

With reference to Figure 5, at block 302, registration procedures are performed.

As illustrated by arrow 304 of Figure 5, the CBE node 30 sends a request to the CBCF node 10. The request 304 is a request to initiate a warning message delivery procedure. The request 304 may be referred to as an emergency broadcast request. The request 304 can be a message. The CBCF node 10 is configured to operate in the manner described earlier with reference to Figure 1. That is, the processing circuitry 12 of the CBCF node 10 is configured to acquire coordinates that define a warning area having a first shape, approximate the warning area to a second shape based on the acquired coordinates (where the second shape is sized to completely enclose the first shape and is a simplified geometric shape compared to the first shape) and transmit parameters that define a perimeter of the second shape towards one or more UEs 20. The transmission of the parameters can be directly towards one or more UEs 20 or indirectly towards one or more UEs 20, such as via one or more other nodes. For example, the transmission of the parameters may be via the AMF node 40 and one or more NG-RAN nodes 50 as in this example embodiment.

In more detail, as illustrated by arrow 306 of Figure 5, the CBCF node 10 sends a request to the AMF node 40. The request 306 contains a warning message to be broadcast to UEs in the warning area and one or more delivery attributes. The delivery attributes usually comprise coordinates that define the warning area having the first shape. That is, the delivery attributes usually comprise warning area coordinates. However, in the example embodiment, the delivery attributes instead comprise the parameters that define the perimeter of the second shape to which the first shape is approximated. Examples of other delivery attributes that the warning message may comprise include, for example, a message identifier, a serial number, a tracking area identifier (ID) list, a warning area, an operation maintenance (OMC) ID, a concurrent warning message (CWM) indicator, a send write-replace-warning- indication, a global radio access node (RAN) ID, or any other delivery attributes, or any combination of delivery attributes. The request 306 may be referred to as a write-replace-warning request. The request 306 can be a message.

As illustrated by arrow 308 of Figure 5, the AMF node 40 sends a response to the CBCF node 10. The response indicates that that the AMF node 40 has started to distribute the warning message to NG-RAN nodes. The response 308 may be referred to as a write-replace warning confirm response. The response 308 can be a message. As illustrated by arrow 310 of Figure 5, upon receipt of the response 308 from the AMF node 40, the CBCF node 10 may send a response to the CBE node 30. The response 310 confirms to the CBE node 30 that the distribution of the warning message has started. The response 310 may be referred to as an emergency broadcast response. The response 310 can be a message.

As illustrated by arrow 312 of Figure 5, the AMF node 40 forwards the write-replace- warning request (illustrated by arrow 306) to one or more NG-RAN nodes 50. The write-replace-warning request 312 comprises the parameters that define the perimeter of the second shape to which the first shape is approximated. At block 314 of Figure 5, the one or more NG-RAN nodes 50 broadcast the warning message to one or more UEs 20. As illustrated by arrow 316 of Figure 5, the one or more NG-RAN nodes 50 return a response to the AMF node 40. The response 316 may be referred to as a write-replace-warning response. The response 316 can be a message.

At block 318 of Figure 5, the UE 20 activates reception of broadcast warning messages, such that it may receive the broadcast warning message. In some embodiments, the UE 20 may only activate reception of broadcast warning messages if it is configured to receive warning messages. For example, in some embodiments, the UE 20 may only activate reception of broadcast warning messages if it is configured to accept warning messages on that public land mobile network (PLMN). The UE 20 determines whether it is located inside or outside the warning area in order to decide whether to indicate the contents of the warning message to a user. The UE 20 is configured to operate in the manner described earlier with reference to Figure 3 in order to make this determination. Thus, in order for a UE 20 to determine whether it is located inside or outside the warning area, the processing circuitry 22 of the UE 20 receives the parameters that define the perimeter of the second shape to which the warning area having the first shape is approximated and determines whether the UE 20 is located inside or outside the second shape based on the received parameters.

If the parameters that define the perimeter of the second shape to which the warning area having the first shape is approximated are not present, the UE 20 indicates the contents of the warning message to the user. If the parameters are present and if the UE 20 is unable to determine its location, the UE 20 indicates the contents of the warning message to the user. If the parameters are present and the UE 20 determines it is inside the second shape, the UE 20 indicates the contents of the warning message to the user. Thus, in these cases, the UE 20 initiates an indication to warn a user of the UE 20 about an emergency situation. If the parameters are present and the UE 20 determines it is outside the second shape, the UE 20 does not indicate the contents of the warning message to the user. Thus, in this case, the UE 20 does not initiate an indication to warn a user of the UE 20 about an emergency situation.

As illustrated by arrow 320 of Figure 5, the AMF node 40 may optionally forward broadcast scheduled area lists in one or more indications to the CBCF node 10. The one or more indications can be referred to as one or more write-replace warning indication. The one or more indications can be one or more messages. At block 322 of Figure 5, the AMF node 40 may determine the success or failure of the delivery from the one or more indications. The AMF node 40 may also create a trace record.

Figure 6 is a simplified schematic of an example warning area according to an embodiment. As mentioned earlier, the warning area comprises an area in which to warn users about an emergency situation.

As illustrated in Figure 6, the example warning area has a first shape 400. In this illustrated example, the first shape 400 is a concave polygon, which has nine sides. However, it will be understood that the first shape 400 may instead be a convex polygon according to other examples and/or may have a different number of sides. The first shape 400 is illustrated in a coordinate system having two perpendicular coordinate axes, namely a y-axis (i.e. a vertical axis) and an x-axis (i.e. a horizontal axis). Thus, the coordinates are of a coordinate system having two perpendicular coordinate axes. In some embodiments, lines of latitude (parallels) and lines of longitude (meridians) may be the two perpendicular coordinate axes of such a coordinate system as in geographical coordinate systems. The perimeter of the first shape is defined by a plurality of coordinates (xi , yi), (x2, yå), (X3, y3), (X4, y4), (xs, ys), (x₆, y₆), (X7, ), (xe, ye), (xg, yg).

As described earlier, the processing circuitry 12 of the node 10 acquires (e.g. from a warning message) the coordinates that define the warning area having the first shape 400 and approximates the warning area to a second shape 402 based on the acquired coordinates. As illustrated in Figure 6, the second shape 402 is sized to completely enclose the first shape 400 and is a simplified geometric shape compared to the first shape 400. More specifically, in this illustrated example, the second shape 402 is a rectangle, which has four sides. The second shape 402 is illustrated in the coordinate system having the two perpendicular coordinate axes, namely the y-axis (i.e. the vertical axis) and the x-axis (i.e. the horizontal axis). In this illustrated example, the warning area having the first shape 400 is approximated to the second shape 402, such that two sides of the second shape are parallel to one of the two perpendicular coordinate axes (e.g. the y-axis) and another two sides of the second shape are parallel to the other one of the two perpendicular coordinate axes (e.g. the x-axis). Thus, the first shape 400 is transformed into an approximated stra ight-sided rectangle 402, which is actually defined by four new coordinates at the corners.

As described earlier, the processing circuitry 12 of the node 10 transmits parameters that define a perimeter of the second shape 402 towards one or more UEs 20. In the example illustrated in Figure 6, the parameters that define the perimeter of the second shape 402 can comprise coordinates of at least two diagonally opposite corners of the second shape, such as (x_ai ,y_a-i) and (x_a3,y_a3) or (x_a2,y_a2) and (x_a ,y_a4). Alternatively, in the example illustrated in Figure 6, the parameters that define the perimeter of the second shape 402 can comprise coordinates of at least three corners of the second shape, such as (x_ai ,y_a-i), (x_a2,y_a2) and (x_a3,y_a3) or coordinates of any other three or more corners. In some embodiments, the parameters that define the perimeter of the second shape 502 can comprise coordinates of a first corner of the second shape 502, only the x-coordinate of a second corner of the second shape 502 and only the y-coordinate of a third corner of the second shape 502, where the first, second and third corners are different. Thus, in the example of Figure 6, the parameters are coordinates of the second shape 402.

Figure 7 is a simplified schematic of an example warning area according to an embodiment. As mentioned earlier, the warning area comprises an area in which to warn users about an emergency situation.

As illustrated in Figure 7(a), the example warning area has a first shape 500. In this illustrated example, the first shape 500 is a convex polygon, which has eight sides. However, it will be understood that the first shape 500 may instead be a concave polygon according to other examples and/or may have a different number of sides. The first shape 500 is illustrated in a coordinate system having two perpendicular coordinate axes, namely a y-axis (i.e. a vertical axis) and an x-axis (i.e. a horizontal axis). Thus, the coordinates are of a coordinate system having two perpendicular coordinate axes. In some embodiments, lines of latitude (parallels) and lines of longitude (meridians) may be the two perpendicular coordinate axes of such a coordinate system as in geographical coordinate systems. The perimeter of the first shape is defined by a plurality of coordinates (xi , y-i), (x2, y_å), (x3, y3), (x4, y4), (xs, ys), (x6, y6), (x7, y?), (xe, ye). Thus, the warning area having a first shape is defined by eight coordinates in this example.

As described earlier, the processing circuitry 12 of the node 10 acquires the coordinates that define the warning area having the first shape 500 and approximates the warning area to a second shape 502 based on the acquired coordinates. As illustrated in Figure 7, the second shape 502 is sized to completely enclose the first shape 500 and is a simplified geometric shape compared to the first shape 500. More specifically, in this illustrated example, the second shape 502 is a rectangle, which has four sides. However, it will be understood that the second shape 502 may alternatively be a square in other examples.

As illustrated in Figures 7(b) and (c), in this example, the warning area having the first shape 500 is approximated to a second shape 502 by identifying an outermost (or extreme) one of the acquired coordinates in each of four cardinal directions, which are the circled coordinates in Figure 7(b). The identified outermost ones of the acquired coordinates are (X2,y2), (X4,y4), (xe.ye) and (xe,ye) in this example. These identified outermost ones of the acquired coordinates can be referred to as the extreme coordinates. The extreme coordinates comprise the northernmost coordinate (x₂,y2), the easternmost coordinate (X4,y4), the southernmost coordinate (cb,gb), and the westernmost coordinate (xe.ye). If there were only three coordinates in the original set of coordinates, one of these three coordinates naturally represents two extreme points.

As described earlier and as illustrated in Figure 7(c), the processing circuitry 12 of the node 10 approximate the warning area having the first shape 500 to the second shape 502, such that each side of the second shape 502 passes through a different identified outermost one of the acquired coordinates, namely a different one of (C_Ϊ,U_Ϊ), (X4,y4), (X₆,y₆) and (xe.ye). Also, in this illustrated example, the warning area having the first shape 500 is approximated to the second shape 502, such that two sides of the second shape are parallel to one of the two perpendicular coordinate axes (e.g. the y- axis) and another two sides of the second shape are parallel to the other one of the two perpendicular coordinate axes (e.g. the x-axis). The second shape 502 is an approximated straight-sided rectangle with four new coordinate pairs representing the corners. The second shape 502 can be considered as the minimal outer rectangle of the original warning area.

As described earlier, the processing circuitry 12 of the node 10 transmits parameters that define a perimeter of the second shape 502 towards one or more UEs 20. In the example illustrated in Figure 7, the parameters that define the perimeter of the second shape 502 can comprise coordinates of at least two diagonally opposite corners of the second shape 502, such as (x_ai ,y_ai) and (x_a3,y_a3) or (x_a2,y_a2) and (x_a4 , y_a4 ) as illustrated in Figure 7(d).

Alternatively, in the example illustrated in Figure 7, the parameters that define the perimeter of the second shape 502 can comprise coordinates of at least three corners of the second shape 502, such as (x_ai ,y_ai), (x_a2,y_a2) and (x_a3,y_a3) as illustrated in Figure 7(d) or coordinates of any other three or more corners illustrated in Figure 7(d). In some embodiments, the parameters that define the perimeter of the second shape 502 can comprise coordinates (an x-coordinate and a y-coordinate) of a first corner of the second shape 502, only the x-coordinate of a second corner of the second shape 502 and only the y-coordinate of a third corner of the second shape 502, where the first, second and third corners are different. With this combination of coordinates, all remaining coordinates are known when the second shape 502 is a rectangle (or square). For example, the coordinates of the first corner may be (x_ai ,y_ai ), the x-coordinate of a second corner may be x_a2 and the y-coordinate of the third corner may be y_a4. All remaining coordinates are known when the second shape 502 is a rectangle (or square) since x_ai = x_a4, y_ai = y_a2, x_a2 = x_a3, and y_a4 = y_a3. In some embodiments, the parameters that define the perimeter of the second shape 502 can comprise all four coordinates of the second shape 502. Thus, in this example, the parameters are (corner) coordinates of the second shape 502. The warning area is in effect defined using new coordinates.

It can be assumed that a warning area is defined by a set of coordinates, as follows:

S = {(Xi,yi)} for i = 1 ,2. k and k > 3, or equivalently s = {(Xi ,yi), (X2.Y2), (Xa.ya) . (Xk,y )} where (c,,g) represents a geographical coordinate.

An approximation function f can be defined, as follows:

where S’ is composed of four new coordinates (i.e. S’= {(x_ai ,y_ai ), (x_a2,y_a2), (x_a3,y_a3), (X_a4 , y_a4 )} ) . For completeness, it is noted that, when the second shape is a circle, S’ is instead composed of coordinates of a centre of the circle and a radius of the circle. The coordinates in S’ represent the corners of a straight rectangle covering the warning area in the context of the example illustrated in Figure 6. The coordinates in the S’ have the following properties because it is a straight rectangle:

Xa1 ^— Xa4

Ya1 = Ya2

y_a3 = y_a4

Without loss of generality, the process can be illustrated with an example for k = 8. Figure 7 illustrates a geometric location of such a set of coordinates for k=8. The warning area is defined by a set of coordinates, which yields the first shape as a polygon. The polygon can be convex or concave. For this example, it is assumed that the coordinates represent the locations illustrated in Figure 7. The processing circuitry 12 of the node 10 may be configured to find a minimal straight rectangle that covers all the original coordinates by determining four new coordinates as the corners of an approximated rectangular area. After this transformation, only coordinates of two diagonally opposite corners of the approximated rectangular area or only three (or four) corner coordinates of the approximated rectangular area need to be transmitted toward the UEs 20. Thus, bandwidth is conserved and the UEs can more easily determine whether they are inside or outside the rectangular area by performing a minimum number of computations, e.g. at most four comparisons. In an example, with reference to Figure 7, it is assumed that the parameters received by the processing circuitry 22 of a UE 20 comprise a set of approximated area coordinates, as follows:

S’ = {(Xa1 ,yal ), (Xa2,Ya2), (Xa3,Ya3), (Xa4 ,Ya4)} ·

Here, x_ai = x_a4, x_a2 = Xa3, y_ai = Ya2, and y_a3 = Ya₄ due to the geometric relationship between the coordinates. In this example, the location of UE is denoted as (XUE.YUE). The UE 20 can, for example, perform the following operations: if XUE < Xai _, then UE is outside the warning area, and do not indicate the contents of the "warning message" to the user;

else if XUE > x_a2 _, then UE is outside the warning area, and do not indicate the contents of the "warning message" to the user;

else if XUE > y_ai . then UE is outside the warning area, and do not indicate the contents of the "warning message" to the user;

else if XUE < y_a4 _, then UE is outside the warning area, and do not indicate the contents of the "warning message" to the user; and

else: you are inside the warning area, and do indicate the contents of the "warning message" to the user.

As shown above, there are at most 4 comparisons required to determine whether a UE is inside or outside the second shape. Without the proposed approximation method, a UE is required to perform many more operations to determine whether it is inside or outside the warning area having the first shape.

Thus, the area approximation method described herein takes many coordinates defining a warning area as input, and yields a minimal number of parameters as output. Figure 8 is a simplified schematic of an example warning area according to an embodiment. As mentioned earlier, the warning area comprises an area in which to warn users about an emergency situation.

As illustrated in Figure 8, the warning area has a first shape 600. In this illustrated example, the first shape 600 is a concave polygon, which has nine sides. However, it will be understood that the first shape 600 may instead be a convex polygon according to other examples and/or may have a different number of sides. The first shape 600 is illustrated in a coordinate system having two perpendicu lar coordinate axes, namely a y-axis (i.e. a vertical axis) and an x-axis (i.e. a horizontal axis). Thus, the coordinates are of a coordinate system having two perpendicular coordinate axes. In some embodiments, lines of latitude (parallels) and lines of longitude (meridians) may be the two perpendicular coordinate axes of such a coordinate system as in geographical coordinate systems. The perimeter of the first shape 600 is defined by a plurality of coordinates (xi , y-i), (x2, y_å), (x3, y3), (x4, y4), (xs, ys), (CQ, y6), (X7, y7), (xs, ye), (X9, yg).

As described earlier, the processing circuitry 12 of the node 10 acquires (e.g. from a warning message) the coordinates that define the warning area having the first shape 600 and approximates the warning area to a second shape 602 based on the acquired coordinates. As illustrated in Figure 8, the second shape 602 is sized to completely enclose the first shape 600 and is a simplified geometric shape compared to the first shape 600. More specifically, in the example illustrated in Figure 8, the second shape 602 is a circle. Thus, the first shape 600 is transformed into a circle 602, which is defined by centre coordinates (x_c,y_c) and a radius r. In this illustrated example, the warning area having the first shape 600 is approximated to the circle 602 using a smallest-circle algorithm, such that the circle 602 contains (or covers) all of the acquired coordinates. The circle 602 is illustrated in the coordinate system having the two perpendicular coordinate axes, namely the y-axis (i.e. the vertical axis) and the x-axis (i.e. the horizontal axis).

As described earlier, the processing circuitry 12 of the node 10 transmits parameters that define a perimeter of the circle 602 towards one or more UEs 20. In the example illustrated in Figure 8, the parameters that define the perimeter of the circle 602 comprise the coordinates (x_c,y_c) of the centre C of the circle 602 and the radius r of the circle 602.

Figure 9 is a simplified schematic of an example warning area according to an embodiment. As mentioned earlier, the warning area comprises an area in which to warn users about an emergency situation. As illustrated in Figure 9(a), the example warning area has a first shape 700. In this illustrated example, the first shape 700 is a concave polygon, which has nine sides. However, it will be understood that the first shape 700 may instead be a convex polygon according to other examples and/or may have a different number of sides. The first shape 700 is illustrated in a coordinate system having two perpendicular coordinate axes, namely a y-axis (i.e. a vertical axis) and an x-axis (i.e. a horizontal axis). Thus, the coordinates are of a coordinate system having two perpendicular coordinate axes. In some embodiments, lines of latitude (parallels) and lines of longitude (meridians) may be the two perpendicular coordinate axes of such a coordinate system as in geographical coordinate systems. The perimeter of the first shape 700 is defined by a plurality of coordinates (xi , y-i), (X2, y_å), (X3, y3), (X4, y4), (xs, ye), (X6, y6), (X7, y?), (xe, ye), (X9, y9). Thus, the warning area having a first shape 700 is defined by nine coordinates in this example.

As described earlier, the processing circuitry 12 of the node 10 acquires the coordinates that define the warning area having the first shape 700 and approximates the warning area to a second shape 702 based on the acquired coordinates. As illustrated in Figure 9(c), the second shape 702 is sized to completely enclose the first shape 700 and is a simplified geometric shape compared to the first shape 700. More specifically, in this illustrated example, the second shape 702 is a circle. The circle 702 has a centre C and a radius r.

As illustrated in Figure 9(b) and (c), in this example, the warning area having the first shape 700 is approximated to the circle 702 by initially approximating the warning area to a rectangle 704 (e.g. in the manner described earlier) and approximating the warning area to the circle 702, such that the centre C of the circle 702 is the centre of the rectangle 704 and the radius r of the circle 702 is half of the distance between two diagonally opposite corners of the rectangle 704, e.g. the corners of the rectangle 704 having coordinates (x_a2,y_a2) and (x_a4,y_a4). Thus, the rectangle 704 can be converted to a circle 702, which is centred at the centre of the rectangle 704 with a diameter equal to a diagonal of the rectangle 704. Although the example illustrates the approximation using a rectangle, it will be understood that a square may be used instead of the rectangle according to other examples. An example of the manner in which the coordinates (x_c,y_c) of the centre C of the circle 702 can be calculated from the corner coordinates of the rectangle 704 (or square) is as follows: Xc = (Xa1 + Xa2) / 2 = (X_a3 + Xa4) / 2 = (X_al + X_a3) / 2 = (X_a2 + X_a4) / 2 y_c= (y_ai + y_a4) / 2 = (y_a2 + y_a3) / 2 = (y_ai + y_a3) / 2 = (y_a2 + y_a4) / 2

The radius r of the circle 702 is equal to half of a diagonal of the rectangle 704 (or square), which is equal to a Euclidian distance between the centre C of the circle 702 and any one of the corner points of the rectangle 704 (or square). Thus, for example, the radius r of the circle 702 may be calculated from the corner coordinates of the rectangle 704 (or square) and the coordinates (x_c,y_c) of the centre C of the circle 702 as follows:

where (x,y) is any one of the corner coordinates of the rectangle 704 (or square). As described earlier, the processing circuitry 12 of the node 10 transmits parameters that define the perimeter of the circle 702 towards one or more UEs 20. In the example illustrated in Figure 9, the parameters that define the perimeter of the second circle 702 comprise the coordinates (x_c,y_c) of the centre C of the circle 702 and the radius r of the circle 702, as illustrated in Figure 9(c).

Figure 10 is a block diagram illustrating a node 800 in accordance with an embodiment. The node 800 comprises an acquiring module 802 configured to acquire coordinates that define a warning area having a first shape. The warning area comprises an area in which to warn users about an emergency situation. The node 800 comprises an approximating module 804 configured to approximate the warning area to a second shape based on the acquired coordinates. The second shape is sized to completely enclose the first shape and is a simplified geometric shape compared to the first shape. The node 800 comprises a transmitting module 806 configured to transmit, towards one or more user equipments, parameters that define a perimeter of the second shape. The node 800 may operate in the manner described herein.

Figure 11 is a block diagram illustrating a UE 900 in accordance with an embodiment. The UE 900 comprises a receiving module 902 configured to receive parameters that define a perimeter of a second shape to which a warning area having a first shape is approximated. The warning area comprises an area in which to warn users about an emergency situation and the second shape is sized to completely enclose the first shape and is a simplified geometric shape compared to the first shape. The UE 900 comprises a determining module 904 configured to determine whether a location of the UE is inside or outside the second shape based on the received parameters. The UE 900 may operate in the manner described herein.

There is also a system, which can comprise at least one node 10, 800 as described herein and at least one user equipment 20, 900 as described herein.

There is also a computer program comprising instructions which, when executed by processing circuitry (such as the processing circuitry 12 of the node and/or the processing circuitry 22 of the UE described earlier), cause the processing circuitry to perform at least part of the method described herein. There is provided a computer program product, embodied on a non-transitory machine-readable medium, comprising instructions which are executable by processing circuitry (such as the processing circuitry 12 of the node and/or the processing circuitry 22 of the UE described earlier) to cause the processing circuitry to perform at least part of the method described herein. There is provided a computer program product comprising a carrier containing instructions for causing processing circuitry (such as the processing circuitry 12 of the node and/or the processing circuitry 22 of the UE described earlier) to perform at least part of the method described herein. In some embodiments, the carrier can be any one of an electronic signal, an optical signal, an electromagnetic signal, an electrical signal, a radio signal, a microwave signal, or a computer-readable storage medium.

The node functionality described herein can be performed by hardware. Thus, any one or more nodes described herein can be a hardware node. However, it will also be understood that at least part or all of the node functionality described herein can be virtualized. For example, the functions performed by any one or more nodes can be implemented in software running on generic hardware that is configured to orchestrate the node functionality. Thus, in some embodiments, any one or more nodes described herein can be a virtual node. In some embodiments, at least part or all of the node functionality described herein may be performed in a network enabled cloud. The node functionality described herein may all be at the same location or at least some of the node functionality may be distributed.

It will be understood that at least some or all of the method steps described herein can be automated in some embodiments. That is, in some embodiments, at least some or all of the method steps described herein can be performed automatically.

Thus, in the manner described herein, there is advantageously provided a technique for defining a warning area and determining whether a UE is inside or outside that warning area.

It should be noted that the above-mentioned embodiments illustrate rather than limit the idea, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. The word “comprising” does not exclude the presence of elements or steps other than those listed in a claim,“a” or“an” does not exclude a plurality, and a single processor or other unit may fulfil the functions of several units recited in the claims. Any reference signs in the claims shall not be construed so as to limit their scope.

Claims

1. A method performed by a node of a network, the method comprising:

acquiring (102) coordinates that define a warning area having a first shape (400, 500, 600, 700), wherein the warning area comprises an area in which to warn users about an emergency situation;

approximating (104) the warning area to a second shape (402, 502, 602, 702) based on the acquired coordinates, wherein the second shape is sized to completely enclose the first shape and is a simplified geometric shape compared to the first shape; and

transmitting (106), towards one or more user equipments, parameters that define a perimeter of the second shape.

2. A method as claimed in claim 1 , wherein:

the second shape is a circle (602, 702); and

the parameters that define the perimeter of the second shape (602, 702) comprise coordinates of a centre of the second shape (602, 702) and a radius of the second shape (602, 702).

3. A method as claimed in claim 2, wherein:

approximating the warning area to the second shape (602) comprises:

approximating the warning area to the second shape (602) using a smallest-circle algorithm, such that the second shape (602) contains all of the acquired coordinates; or

approximating the warning area to the second shape (702) comprises:

approximating the warning area to a square or rectangle (704); and approximating the warning area to the second shape (702), such that the centre of the second shape (702) is a centre of the square or rectangle (704) and the radius of the second shape (702) is half of a distance between two diagonally opposite corners of the square or rectangle (704).

4. A method as claimed in claim 1 , wherein:

the second shape is a square or a rectangle (402, 502); and the parameters that define the perimeter of the second shape (402, 502) comprise coordinates of at least two diagonally opposite corners of the second shape (402, 502) or coordinates of at least three corners of the second shape (402, 502).

5. A method as claimed in claim 4, wherein:

approximating (104) the warning area to the second shape (402, 502) comprises: identifying an outermost one of the acquired coordinates in each of four cardinal directions; and

approximating the warning area to the second shape (402, 502), such that each side of the second shape (402, 502) passes through a different identified outermost one of the acquired coordinates.

6. A method as claimed in claim 4 or 5, wherein:

the acquired coordinates are coordinates of a coordinate system having two perpendicular coordinate axes; and

the warning area is approximated to the second shape (402), such that two sides of the second shape (402) are parallel to one of the two perpendicular coordinate axes and another two sides of the second shape (402) are parallel to the other one of the two perpendicular coordinate axes.

7. A node (10) configured to operate in accordance with any of claims 1 to 6.

8. A node (10) according to claim 7, wherein the node comprises:

processing circuitry (12); and

at least one memory (14) for storing instructions which, when executed by the processing circuitry (12), cause the node (10) to operate in accordance with any of claims 1 to 6.

9. A method performed by a user equipment of a network, the method comprising: receiving (202) parameters that define a perimeter of a second shape (402, 502,

602, 702) to which a warning area having a first shape (400, 500, 600, 700) is approximated, wherein the warning area comprises an area in which to warn users about an emergency situation and the second shape (402, 502, 602, 702) is sized to completely enclose the first shape (400, 500, 600, 700) and is a simplified geometric shape compared to the first shape (400, 500, 600, 700); and determining (204) whether a location of the user equipment is inside or outside the second shape (402, 502, 602, 702) based on the received parameters.

10. A method as claimed in claim 9, wherein:

the second shape (602, 702) is a circle; and

11. A method as claimed in claim 10, wherein:

determining (204) whether a location of the user equipment is inside or outside the second shape (602, 702) comprises:

comparing a distance from the location of the user equipment to the centre of the second shape (602, 702) to the radius of the second shape (602, 702); and

if the distance from the location of the user equipment to the centre of the second shape (602, 702) is less than or equal to the radius of the second shape (602, 702), determining that the location of the user equipment is inside the second shape (602, 702); or

if the distance from the location of the user equipment to the centre of the second shape (602, 702) is greater than the radius of the second shape (602, 702), determining that the location of the user equipment is outside the second shape (602, 702).

12. A method as claimed in claim 1 1 , wherein:

the distance from the location of the user equipment to the centre of the second shape (602, 702) comprises a Euclidean distance.

13. A method as claimed in claim 9, wherein:

the second shape (402, 502) is a square or a rectangle; and

the parameters that define the perimeter of the second shape (402, 502) comprise reference coordinates, wherein the reference coordinates comprise coordinates of at least two diagonally opposite corners of the second shape (402, 502) or coordinates of at least three corners of the second shape (402, 502).

14. A method as claimed in claim 13, wherein:

determining (204) whether a location of the user equipment is inside or outside the second shape (402, 502) comprises:

comparing coordinates of the location of the user equipment to the reference coordinates; and

if an x-coordinate of the location of the user equipment is between a smallest x-coordinate of the reference coordinates and a largest x-coordinate of the reference coordinates and a y-coordinate of the location of the user equipment is between a smallest y-coordinate of the reference coordinates and a largest y- coordinate of the reference coordinates, determining that the location of the user equipment is inside the second shape (402, 502); or

if an x-coordinate of the location of the user equipment is less than a smallest x-coordinate of the reference coordinates, an x-coordinate of the location of the user equipment is greater than a largest x-coordinate of the reference coordinates, a y-coordinate of the location of the user equipment is less than a smallest y-coordinate of the reference coordinates, or a y-coordinate of the location of the user equipment is greater than a largest y-coordinate of the reference coordinates, determining that the location of the user equipment is outside the second shape (402, 502).

15. A method as claimed in any of claims 9 to 14, the method comprising:

if the location of the user equipment is determined to be inside the second shape (402, 502, 602, 702):

initiating an indication to warn a user of the user equipment about an emergency situation.

16. A user equipment (20) configured to operate in accordance with any of claims 9 to 15.

17. A user equipment (20) according to claim 16, wherein the user equipment comprises:

processing circuitry (22); and

at least one memory (24) for storing instructions which, when executed by the processing circuitry (22), cause the user equipment (20) to operate in accordance with any of claims 9 to 15.

18. A system comprising:

at least one node (10) as claimed in any of claims 7 to 8; and

at least one user equipment (20) as claimed in any of claims 16 to 17.

19. A computer program comprising instructions which, when executed by processing circuitry, cause the processing circuitry to perform the method according to any one or more of claims 1-6 and 9-15.

20. A computer program product, embodied on a non-transitory machine-readable medium, comprising instructions which are executable by processing circuitry to cause the processing circuitry to perform the method according to any one or more of claims 1 -6 and 9-15.