Devices and methods for radio resource pool selection for sidelink communication based on tessellations of 2D and 3D space

TECHNICAL FIELD

In general, the present invention relates to the field of sidelink communication. More specifically, the present invention relates to devices and methods for radio resource pool selection for sidelink communication, in particular a sidelink communication device, a network management entity as well as corresponding methods.

BACKGROUND

V2X (Vehicle-to-Everything) services can be provided directly via a so-called PC5 interface - also known as sidelink or device-to-device (D2D) communication - and/or indirectly via an LTE-Uu interface (also known as uplink/downlink), as specified in 3GPP TS 36.300, "LTE; Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2". Support of V2X services via the PC5 interface is provided by V2X sidelink communication, which is a communication mode in which User Equipments (UEs), such as vehicles, can communicate with each other directly via the PC5 interface. This communication mode is supported when the UE is served by E-UTRAN and when the UE is outside of E-UTRA coverage.

A UE supporting V2X sidelink communication can operate in two modes for sidelink radio resource allocation: in a first mode, known as scheduled resource allocation, a UE requests transmission radio resources from a base station, also known as Evolved Node B (eNB), and the base station allocates dedicated transmission radio resources to the UE. In a second mode, known as UE autonomous resource selection, the UE on its own selects radio resources from (pre)configured resource pools.

In order to ensure low interference among V2X sidelink transmissions when using UE autonomous resource selection (also known as "sidelink transmission mode 4"), two features are introduced in specification 3GPP TS 36.331 "Radio Resource Control (RRC)". The first feature relates to zones : the world is divided into geographical zones, wherein a zone is a periodically repeating geographic region (in longitude and latitude). The UE selects a radio resource pool based on the zone in which it is located. The second feature relates to sensing : based on channel sensing within the selected radio resource pool, the UE selects specific sidelink radio resources within that pool for transmission.

Each radio resource pool is associated with an identifier zonelD identifying the zone in which the pool may be used. Based on its location, a UE derives the identity of the zone in which it is located on the basis of the following equation: wherein v _x and v ₂ are defined by the following equations:

wherein x denotes the distance between the current location of the UE and a reference point (0, 0) in longitude, y denotes the distance between the current location of the UE and a reference point (0, 0) in latitude, L denotes the zone length ( zoneLength ), W denotes the zone width ( zoneWidth ), N _x c/enotes the number of zones configured with respect to longitude (zoneldLongiMod) and N _y denotes the number of zones configured with respect to latitude ( zoneldLatiMod ).

The location of the reference point (0, 0) and the parameters L, w, N _x and N _y can be configured by the network operator or preconfigured in the UE. The UE then selects a radio resource pool configured with the corresponding zonelD.

Figure 1 shows a schematic diagram illustrating an exemplary conventional zone configuration with N _x = N _y = 3 and L = W according to a square tiling (i.e., tessellation) of the Euclidean plane, wherein filled squares correspond to zone 0.

However, the zone concept proposed in specification 3GPP TS 36.331 has the limitation that the square tiling of the plane is not the densest way to arrange circles in two dimensions. Instead, the closest packing of circles is achieved by the hexagonal tiling, resulting in the highest possible spectral efficiency per unit area. Furthermore, the zone concept proposed in specification 3GPP TS 36.331 is limited to 2- dimensional (2D) regions (longitude, latitude). Some applications (e.g., drones) may benefit from considering the vertical dimension (elevation) as well, i.e., 3-dimensional (3D) regions (longitude, latitude, elevation).

In light of the above, there is a need for improved devices and methods for radio resource pool selection for sidelink communication on the basis of more efficient tessellations of 2- dimensional (2D) and 3-dimensional (3D) space.

SUMMARY

It is an object of the invention to provide improved devices and methods for radio resource pool selection for sidelink communication on the basis of more efficient tessellations of 2- dimensional (2D) and 3-dimensional (3D) space.

The foregoing and other objects are achieved by the subject matter of the independent claims. Further implementation forms are apparent from the dependent claims, the description and the figures.

Generally, embodiments of the present invention can select radio resource pools for sidelink communication (e.g., V2X sidelink communication) based on several different space-filling tessellations of 2-dimensional and/or 3-dimensional Euclidean space. More specifically, a sidelink communication device according to embodiments can determine the identity of the zone in which it is located, within the corresponding space-filling tessellation, and select a radio resource pool accordingly.

Thus, according to a first aspect, the invention relates to a sidelink communication device, wherein the sidelink communication device comprises: a communication interface configured to communicate with another sidelink communication device using one or more radio resources of at least one radio resource pool of a plurality of radio resource pools; and a processing unit configured to determine a zone identity on the basis of a spatial position of the sidelink communication device, and select the at least one radio resource pool of the plurality of radio resource pools on the basis of the zone identity; wherein the zone identity identifies a zone comprising one or more regions, in particular tessellation elements, having one or more of the following shapes: in case of a 2-dimensional zone, at least one of a triangle or a hexagon; in case of a 3-dimensional zone, a space-filling polyhedron, in particular a parallelohedron.

Thus, an improved sidelink communication device is provided, allowing for radio resource pool selection for sidelink communication on the basis of more efficient tessellations of 2- dimensional (2D) and 3-dimensional (3D) space.

In a further possible implementation form of the first aspect, the shape depends on the spatial position of the sidelink communication device.

In a further possible implementation form of the first aspect, the zone comprises at least three regions, in particular equidistant regions, wherein the regions are non-adjacent.

In a further possible implementation form of the first aspect, the zone identity is calculable by the following equation:

where

with the axes a, given by

and a contour line function k,- given by

where

where wherein x denotes a longitude component of the spatial position of the sidelink communication device, y denotes a latitude component of the spatial position of the sidelink communication device, L denotes the diameter of the incircle of a tessellation element (hexagon) and N denotes a radio resource pool reuse distance, expressed as a number of contiguous tessellation elements.

In a further possible implementation form of the first aspect, the (x, y) frame of reference is translated and/or rotated with respect to the geographic coordinate (longitude/latitude) frame of reference of the sidelink communication device.

In a further possible implementation form of the first aspect, the zone identity is calculable by the following equation:

where

wherein x denotes a longitude component of the spatial position of the sidelink communication device, y denotes a latitude component of the spatial position of the sidelink communication device, z denotes an elevation component of the spatial position of the sidelink communication device, L, W and D denote, respectively, the dimensions of a tessellation element (cuboid) in longitude, latitude and elevation, and N _x , N _y and N _z denote radio resource pool reuse distances with respect to longitude, latitude and elevation, respectively, expressed as a number of contiguous tessellation elements.

In a further possible implementation form of the first aspect, the zone identity is calculable by the following equation:

where

with the axes a,· given by

and a contour line function given by

where

where

wherein x denotes a longitude component of the spatial position of the sidelink communication device, y denotes a latitude component of the spatial position of the sidelink communication device, z denotes an elevation component of the spatial position of the sidelink communication device, L and D denote, respectively, the diameter and height of the incylinder of a tessellation element (hexagonal prism), N denotes a horizontal radio resource pool reuse distance and N _z denotes a radio resource pool reuse distance with respect to elevation, expressed as a number of contiguous tessellation elements.

In a further possible implementation form of the first aspect, the zone identity is calculable by the following equation:

where

with the axes a _; given by

and a contour surface function K, given by

wherein x denotes a longitude component of the spatial position of the sidelink communication device, y denotes a latitude component of the spatial position of the sidelink communication device, z denotes an elevation component of the spatial position of the sidelink communication device, L denotes the diameter of the insphere of a tessellation element (rhombic dodecahedron) and N denotes a radio resource pool reuse distance, expressed as a number of contiguous tessellation elements.

In a further possible implementation form of the first aspect, the ( x, y, z ) frame of reference is translated and/or rotated with respect to the geographic coordinate

(longitude/latitude/elevation) frame of reference of the sidelink communication device.

In a further possible implementation form of the first aspect, the zone identity is determined by finding the nearest of a plurality of lattice points.

In a further possible implementation form of the first aspect, the processing unit is configured to determine the zone identity on the basis of the spatial position of the sidelink communication device and on the basis of zone configuration information provided by a network management entity or preconfigured in the sidelink communication device, wherein the zone configuration information comprises any of the following: a frame of reference, in particular a translation and/or rotation with respect to the geographic coordinate (longitude/latitude/elevation) frame of reference, one or more tessellation element size parameters (L, w, D), one or more lattice points, one or more radio resource pool reuse distance parameters (N _x , N _y , N _z , N), information specifying a tessellation type.

In a further possible implementation form of the first aspect, the processing unit is configured to select the at least one radio resource pool of the plurality of radio resource pools on the basis of the zone identity and on the basis of resource pool configuration information provided by a network management entity or preconfigured in the sidelink communication device, wherein the resource pool configuration information comprises information about the respective radio resource pools of the plurality of radio resource pools allocated to each zone identity.

According to a second aspect, the invention relates to a method for operating a sidelink communication device, wherein the method comprises: determining a zone identity on the basis of a spatial position of the sidelink communication device; selecting at least one radio resource pool of a plurality of radio resource pools on the basis of the zone identity; and communicating with another sidelink communication device using one or more radio resources of the at least one selected radio resource pool; wherein the zone identity identifies a zone comprising one or more regions, in particular tessellation elements, having one or more of the following shapes: in case of a 2-dimensional zone, at least one of a triangle or a hexagon; in case of a 3-dimensional zone, a space-filling polyhedron, in particular a parallelohedron.

Thus, an improved method is provided, allowing for radio resource pool selection for sidelink communication on the basis of more efficient tessellations of 2-dimensional (2D) and 3-dimensional (3D) space.

According to a third aspect, the invention relates to a network management entity, in particular a base station or cloud server. The network management entity comprises a processing unit configured to generate zone configuration information, wherein the zone configuration information comprises any of the following: a frame of reference, in particular a translation and/or rotation with respect to the geographic coordinate

(longitude/latitude/elevation) frame of reference, one or more tessellation element size parameters (L, w, D), one or more lattice points, one or more radio resource pool reuse distance parameters (N _x , N _y , N _z , N), information specifying a tessellation type; and/or resource pool configuration information, wherein the resource pool configuration information comprises information about one or more radio resource pools of a plurality of radio resource pools allocated to one or more zone identities. The network management entity further comprises a communication interface configured to provide the zone configuration information and/or resource pool configuration information to the sidelink communication device. A zone identity identifies a zone comprising one or more regions, in particular tessellation elements, having one or more of the following shapes: in case of a 2-dimensional zone, at least one of a triangle or a hexagon; in case of a 3-dimensional zone, a space-filling polyhedron, in particular a parallelohedron.

Thus, an improved network management entity is provided, allowing for radio resource pool selection for sidelink communication on the basis of more efficient tessellations of 2- dimensional (2D) and 3-dimensional (3D) space.

According to a fourth aspect, the invention relates to a method for allocating radio resource pools to a sidelink communication device. The method comprises the following steps: generating zone configuration information and/or resource pool configuration information, wherein the resource pool configuration information comprises information about one or more radio resource pools of a plurality of radio resource pools allocated to one or more zone identities; and providing the zone configuration information and/or resource pool configuration information to the sidelink communication device; wherein a zone identity identifies a zone comprising one or more regions, in particular tessellation elements, having one or more of the following shapes: in case of a 2-dimensional zone, at least one of a triangle or a hexagon; in case of a 3-dimensional zone, a space-filling polyhedron, in particular a parallelohedron.

Thus, an improved method for allocating radio resource pools to a sidelink communication device is provided.

According to a fifth aspect, the invention relates to a computer program comprising program code for performing the method of the second aspect or the method of the fourth aspect when executed on a computer.

The invention can be implemented in hardware and/or software.

BRIEF DESCRIPTION OF THE DRAWINGS

Further embodiments of the invention will be described with respect to the following figures, wherein:

Figure 1 shows a schematic diagram illustrating an exemplary zone configuration according to the prior art;

Figure 2 shows a schematic diagram illustrating a sidelink communication device according to an embodiment and a network management entity according to an embodiment;

Figure 3 shows a schematic diagram illustrating 2-dimensional spatial regions used by a sidelink communication device according to an embodiment;

Figure 4 shows a schematic diagram illustrating the variables used for calculating the contour line function in the (x,y) frame of reference;

Figure 5 shows a schematic diagram illustrating 3-dimensional spatial regions used by a sidelink communication device according to an embodiment; Figure 6 shows a schematic diagram illustrating 3-dimensional spatial regions used by a sidelink communication device according to an embodiment;

Figure 7 shows a schematic diagram illustrating 3-dimensional spatial regions used by a sidelink communication device according to an embodiment;

Figure 8A shows a schematic diagram illustrating the axes a _;· and the contour surface used for calculating the zone identity by a sidelink communication device according to an embodiment;

Figure 8B shows a schematic diagram illustrating the orthogonal projection of the contour surface of figure 8A onto the (u,·, v,·) -plane perpendicular to each of the axes a _;· , and the variables used for calculating the contour surface function KJ in the (x, y, z) frame of reference;

Figure 9 shows a diagram illustrating a method for operating a sidelink communication device according to an embodiment; and

Figure 10 shows a diagram illustrating a method for allocating radio resource pools to a sidelink communication device according to an embodiment.

In the various figures, identical reference signs will be used for identical or at least functionally equivalent features.

DETAILED DESCRIPTION OF EMBODIMENTS

In the following description, reference is made to the accompanying drawings, which form part of the disclosure, and in which are shown, by way of illustration, specific aspects in which the present invention may be placed. It will be appreciated that other aspects may be utilized and structural or logical changes may be made without departing from the scope of the present invention. The following detailed description, therefore, is not to be taken in a limiting sense, as the scope of the present invention is defined by the appended claims.

For instance, it will be appreciated that a disclosure in connection with a described method may also hold true for a corresponding device or system configured to perform the method and vice versa. For example, if a specific method step is described, a

corresponding device may include a unit to perform the described method step, even if such unit is not explicitly described or illustrated in the figures.

Moreover, in the following detailed description as well as in the claims, embodiments with different functional blocks or processing units are described, which are connected with each other or exchange signals. It will be appreciated that the present invention covers embodiments as well, which include additional functional blocks or processing units that are arranged between the functional blocks or processing units of the embodiments described below.

Finally, it is understood that the features of the various exemplary aspects described herein may be combined with each other, unless specifically noted otherwise.

Figure 2 shows a schematic diagram illustrating a communication network 200 comprising a sidelink communication device 201 according to an embodiment and a network management entity 231 according to an embodiment. The sidelink communication device 201 is configured to communicate with another sidelink communication device (not shown in figure 2) via a sidelink (or D2D) communication channel and communicate with the network management entity 231 via an uplink/downlink communication channel. In an embodiment, the network management entity 231 can be part of a cellular communication network comprising a plurality of base stations. In an embodiment, the network management entity 231 can be implemented as a part of such a base station. In an embodiment, the uplink/downlink communication channel can be provided by a 5G communication network.

In the embodiment shown in figure 2, the sidelink communication device 201 could be implemented in the form of a vehicle or a communication module of a vehicle. However, it will be appreciated that embodiments of the invention apply to sidelink communication devices other than vehicles as well, such as mobile phones and the like.

As illustrated in figure 2, the sidelink communication device 201 comprises a

communication interface 203 configured to communicate with another sidelink

communication device using one or more radio resources of at least one radio resource pool of a plurality of radio resource pools. In an embodiment, the communication network is a 5G communication network and the radio resources are provided by the 5G communication network.

Furthermore, the sidelink communication device 201 comprises a processing unit 205. As will be described in more detail in the context of figures 3 to 8, the processing unit 205 is configured to determine a zone identity on the basis of a spatial position of the sidelink communication device 201 and select the at least one radio resource pool of the plurality of radio resource pools on the basis of the zone identity, wherein the zone identity identifies a zone comprising one or more regions, in particular tessellation elements, having one or more of the following shapes: in case of a 2-dimensional zone, at least one of a triangle or a hexagon; in case of a 3-dimensional zone, a space-filling polyhedron, in particular a parallelohedron.

A parallelohedron is a polyhedron that can tessellate 3-dimensional space with face-to- face contacts via translations. This requires all opposite faces be congruent.

Parallelohedra can only have parallelogonal faces, either parallelograms or hexagons with parallel opposite edges. There are five such parallelohedra: the cube, hexagonal prism, elongated dodecahedron, rhombic dodecahedron, and truncated octahedron.

In an embodiment, the shape depends on the spatial position of the sidelink

communication device 201 . In an embodiment, a zone comprises at least three regions, in particular equidistant regions, wherein the regions are non-adjacent.

As can be taken from figure 2, the network management entity 231 comprises a processing unit 235 configured to generate zone configuration information, wherein the zone configuration information comprises any of the following: a frame of reference, in particular a translation and/or rotation with respect to the geographic coordinate

(longitude/latitude/elevation) frame of reference, one or more tessellation element size parameters (L, w, D), one or more lattice points, one or more radio resource pool reuse distance parameters (N _x , N _y , N _z , N), information specifying a tessellation type.

Moreover, the processing unit 235 can be further configured to generate resource pool configuration information comprising information about one or more radio resource pools of a plurality of radio resource pools allocated to one or more zone identities. A zone identity identifies a zone comprising one or more regions, in particular tessellation elements, having one or more of the following shapes: in case of a 2-dimensional zone, at least one of a triangle or a hexagon; in case of a 3-dimensional zone, a space-filling polyhedron, in particular a parallelohedron.

The network management entity 231 further comprises a communication interface 233 configured to provide the zone configuration information and/or resource pool

configuration information to the sidelink communication device 201 via the downlink channel.

The processing unit 205 of the sidelink communication device 201 can be further configured to determine the zone identity on the basis of the spatial position of the sidelink communication device 201 and on the basis of the zone configuration information provided by the network management entity 231 or preconfigured in the sidelink communication device 201 .

Moreover, the processing unit 205 is further configured to select the at least one radio resource pool of the plurality of radio resource pools on the basis of the zone identity and on the basis of the resource pool configuration information provided by the network management entity 231 or preconfigured in the sidelink communication device 201 .

Under reference to figures 3 to 8, details about various tessellations of 2-dimensional and 3-dimensional spatial regions used by the sidelink communication device 201 will be introduced in the following, wherein tessellation elements of these tessellations include hexagons (in two dimensions) and cuboids, hexagonal prisms as well as rhombic dodecahedra (in three dimensions). As will be shown in the following embodiments, the sidelink communication device 201 , for instance, in the form of a vehicle, can identify a zone within which the vehicle may use a certain radio resource pool for V2X sidelink communication. The sidelink communication device 201 , by way of example, can be a car or a drone and can be provided with the following information either via preconfiguration or by a network management entity 231 , such as a base station or cloud server: a frame of reference, in particular a translation and/or rotation with respect to the geographic coordinate (longitude/latitude/elevation) frame of reference, one or more tessellation element size parameters (L, w, D), one or more radio resource pool reuse distance parameters (N _x , N _y , N _z , N), and information specifying a tessellation type. Alternatively, the sidelink communication device can be provided with a plurality of lattice points. Based on its current location and the provided information, the sidelink communication device 201 can determine the zone in which it is located. In particular, it can determine the zone identity by finding the nearest of the plurality of lattice points. In addition, the sidelink communication device is provided with a mapping of radio resource pools to zone identities. The sidelink communication device then selects the appropriate radio resource pool on the basis of the zone in which it is located.

Figure 3 shows a schematic diagram illustrating 2-dimensional spatial regions used by the sidelink communication device 201 according to a hexagonal tessellation in an embodiment, wherein the radio resource pool reuse distance N is 3 and the filled hexagons correspond to zone 0. The hexagonal tiling or hexagonal tessellation is a regular tiling of the Euclidean plane, in which three hexagons meet at each vertex. The hexagonal tessellation is the densest way to arrange circles in two dimensions.

The area of a square of side length L \s A _s = L ² , while the area of a hexagon with inradius

L/2 (as shown in figure 3) is A _h —L ² . Assuming a uniform distribution of sidelink communication devices 201 on the Euclidean plane, the average number of sidelink communication devices 201 in a square cell is 2/V3 times that in a hexagonal cell. As a result, for a given reuse distance d = NL, the spectral efficiency per unit area of the hexagonal tessellation is 2/V3 times that of the square tessellation (-15% higher). This is also the highest possible spectral efficiency per unit area in two dimensions (under the assumption of uniformly distributed traffic demand), since it corresponds to the densest circle-packing.

Each radio resource pool is configured with a zone identity identifying the zone in which the pool may be used. More specifically, in this embodiment, the sidelink communication device 201 is first configured to determine a zone identity on the basis of a spatial position (x,y) of the sidelink communication device 201 on the basis of the following equation:

where

with the axes a, given by

and a contour line function k,- given by where

where

wherein x denotes a longitude component of the spatial position of the sidelink communication device 201 , y denotes a latitude component of the spatial position of the sidelink communication device 201 , L denotes the diameter of the incircle of a tessellation element (hexagon) and N denotes a radio resource pool reuse distance, expressed as a number of contiguous tessellation elements.

Figure 4 shows a schematic diagram illustrating the variables / and m used for calculating the contour line function in the (x,y) frame of reference.

The (x,y) frame of reference may be translated and/or rotated with respect to the geographic coordinate (longitude/latitude) frame of reference of the sidelink

communication device 201 .

After determining the zone identity, the sidelink communication device 201 can select a radio resource pool configured with the corresponding zone identity. The diameter L of the incircle of the hexagonal element and the radio resource pool reuse distance N can be configured by the network operator or preconfigured in the sidelink communication device 201 .

Figure 5 shows a schematic diagram illustrating 3-dimensional spatial regions used by the sidelink communication device 201 according to a cubic tessellation in an embodiment, wherein the radio resource pool reuse distances with respect to longitude, latitude and elevation N _x , N _y and N _z are 3, the dimensions L, W, D of a tessellation element in longitude, latitude and elevation are equal, and the filled cubes correspond to zone 0. The cubic tessellation (or cubic honeycomb) is the only regular space-filling tessellation in 3- dimensional Euclidean space. In this embodiment, the sidelink communication device 201 is configured to determine a zone identity on the basis of a spatial position of the sidelink communication device 201 on the basis of the following equation:

where

wherein x denotes a longitude component of the spatial position of the sidelink

communication device 201 , y denotes a latitude component of the spatial position of the sidelink communication device 201 , z denotes an elevation component of the spatial position of the sidelink communication device 201 , L, W and D denote, respectively, the dimensions of a tessellation element (cuboid) in longitude, latitude and elevation, and N _x , N _y and N _z denote radio resource pool reuse distances with respect to longitude, latitude and elevation, respectively, expressed as a number of contiguous tessellation elements.

The (x, y, z) frame of reference may be translated and/or rotated with respect to the geographic coordinate (longitude/latitude/elevation) frame of reference of the sidelink communication device 201. This also applies to the following embodiments related to different 3-dimensional tessellations.

The sidelink communication device 201 then selects a radio resource pool configured with the corresponding zone identity. The following parameters can be configured by the network operator or preconfigured in the sidelink communication device 201 : the dimensions L, W and D of a tessellation element (cuboid) in longitude, latitude and elevation as well as the radio resource pool reuse distances N _x , N _y and N _z with respect to longitude, latitude and elevation.

Figure 6 shows a schematic diagram illustrating 3-dimensional spatial regions used by the sidelink communication device 201 according to a hexagonal prismatic tessellation in an embodiment, wherein the horizontal radio resource pool reuse distance N as well as the radio resource pool reuse distance with respect to elevation N _z are 3 and the filled hexagons correspond to zone 0. The hexagonal prismatic tessellation (or hexagonal prismatic honeycomb) is a space-filling tessellation in 3-dimensional Euclidean space and the tessellation elements are hexagonal prisms. It can be constructed from a hexagonal tiling extruded into prisms.

In this embodiment, the sidelink communication device 201 is configured to determine a zone identity on the basis of a spatial position of the sidelink communication device 201 on the basis of the following equation:

where

with the axes a, given by

and a contour line function k,- given by

where

where

wherein x denotes a longitude component of the spatial position of the sidelink communication device 201 , y denotes a latitude component of the spatial position of the sidelink communication device 201 , z denotes an elevation component of the spatial position of the sidelink communication device 201 , L and D denote, respectively, the diameter and height of the incylinder of a tessellation element (hexagonal prism), N denotes a horizontal radio resource pool reuse distance and N _z denotes a radio resource pool reuse distance with respect to elevation, expressed as a number of contiguous tessellation elements.

Next, the sidelink communication device 201 selects a radio resource pool configured with the corresponding zone identity. The following parameters can be configured by the network operator or preconfigured in the sidelink communication device 201 : the diameter L and height D of the incylinder of a tessellation element (hexagonal prism), the horizontal radio resource pool reuse distance N and the resource pool reuse distance N _z with respect to elevation.

Figure 7 shows a schematic diagram illustrating 3-dimensional spatial regions used by the sidelink communication device 201 according to a rhombic dodecahedral tessellation in an embodiment, wherein the radio resource pool reuse distance N is 3 and the filled rhombic dodecahedra correspond to zone 0. The rhombic dodecahedral tessellation (or rhombic dodecahedral honeycomb) is a space-filling tessellation in 3-dimensional Euclidean space and the tessellation elements are rhombic dodecahedra. It is the Voronoi diagram of the face-centered cubic (fee) sphere-packing, which has the densest possible packing of equal spheres in ordinary space.

The volume of a cube of side length L while the volume of a rhombic

dodecahedron with inradius L/2 (as shown in figure 7) is V Assuming a uniform

distribution of sidelink communication devices 201 in 3-dimensional space, the average number of sidelink communication devices 201 in a cubic cell is√2 times that in a rhombic dodecahedral cell. As a result, for a given reuse distance the spectral efficiency per unit volume of the rhombic dodecahedral tessellation is√2 times that of the cubic tessellation (-41% higher). It is also the highest possible spectral efficiency per unit volume in three dimensions (under the assumption of uniformly distributed traffic demand), since it corresponds to the densest sphere-packing.

In this embodiment, the sidelink communication device 201 is configured to determine a zone identity on the basis of a spatial position of the sidelink communication device 201 on the basis of the following equation:

where with the axes a, given by

and a contour surface function k,- given by

where

and

where

wherein x denotes a longitude component of the spatial position of the sidelink communication device 201 , y denotes a latitude component of the spatial position of the sidelink communication device 201 , z denotes an elevation component of the spatial position of the sidelink communication device 201 , L denotes the diameter of the insphere of a tessellation element (rhombic dodecahedron) and N denotes a radio resource pool reuse distance, expressed as a number of contiguous tessellation elements.

Figure 8A shows a schematic diagram illustrating the axes a _;· and the contour surface used for calculating the zone identity by the sidelink communication device 201 according to a rhombic dodecahedral tessellation in an embodiment, and figure 8B shows the orthogonal projection of the contour surface of figure 8A onto the ( - plane

perpendicular to each of the axes a _;· .

The and ( components used for calculating the contour surface function KJ

are determined based on corresponding rotations of the coordinate system by ( a -

p/2) and (a/2) respectively, wherein is the acute angle of each rhombic

face.

After determining the zone identity, the sidelink communication device 201 can select a radio resource pool associated with the corresponding zone identity. The diameter L of the insphere of a tessellation element (rhombic dodecahedron) and the radio resource pool reuse distance N can be configured by the network operator or preconfigured in the sidelink communication device 201 .

Figure 9 shows a diagram illustrating a corresponding method 900 for operating the sidelink communication device 201 according to an embodiment. The method 900 comprises a first step of determining 901 a zone identity on the basis of a spatial position of the sidelink communication device 201 , wherein the zone identity identifies a zone comprising one or more regions, in particular tessellation elements, having one or more of the following shapes: in case of a 2-dimensional zone, at least one of a triangle or a hexagon; in case of a 3-dimensional zone, a space-filling polyhedron, in particular a parallelohedron.

The method 900 further comprises the steps of selecting 903 at least one radio resource pool of a plurality of radio resource pools on the basis of the zone identity; and

communicating 905 with another sidelink communication device using one or more radio resources of the at least one selected radio resource pool.

Figure 10 shows a diagram illustrating a corresponding method 1000 for allocating radio resource pools to the sidelink communication device 201 according to an embodiment.

The method 1000 comprises a step of generating 1001 zone configuration information and/or resource pool configuration information, wherein the resource pool configuration information comprises information about one or more radio resource pools of a plurality of radio resource pools allocated to one or more zone identities, and wherein a zone identity identifies a zone comprising one or more regions, in particular tessellation elements, having one or more of the following shapes: in case of a 2-dimensional zone, at least one of a triangle or a hexagon; in case of a 3-dimensional zone, a space-filling polyhedron, in particular a parallelohedron.

The method 1000 further comprises a step of providing 1003 the zone configuration information and/or resource pool configuration information to the sidelink communication device 201.

While a particular feature or aspect of the disclosure may have been disclosed with respect to only one of several implementations or embodiments, such feature or aspect may be combined with one or more other features or aspects of the other implementations or embodiments as may be desired and advantageous for any given or particular application. Furthermore, to the extent that the terms "include", "have", "with", or other variants thereof are used in either the detailed description or the claims, such terms are intended to be inclusive in a manner similar to the term "comprise". Also, the terms "exemplary", "for example" and "e.g." are merely meant as an example, rather than the best or optimal. The terms“coupled” and“connected”, along with derivatives may have been used. It should be understood that these terms may have been used to indicate that two elements cooperate or interact with each other regardless of whether they are in direct physical or electrical contact, or they are not in direct contact with each other. Although specific aspects have been illustrated and described herein, it will be

appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific aspects shown and described without departing from the scope of the present disclosure. This application is intended to cover any adaptations or variations of the specific aspects discussed herein.

Although the elements in the following claims are recited in a particular sequence with corresponding labeling, unless the claim recitations otherwise imply a particular sequence for implementing some or all of those elements, those elements are not necessarily intended to be limited to being implemented in that particular sequence.

Many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the above teachings. Of course, those skilled in the art readily recognize that there are numerous applications of the invention beyond those described herein. While the present invention has been described with reference to one or more particular embodiments, those skilled in the art recognize that many changes may be made thereto without departing from the scope of the present invention. It is therefore to be understood that within the scope of the appended claims and their equivalents, the invention may be practiced otherwise than as specifically described herein.