WO2021099923A1

WO2021099923A1 - Smf-supported application-specific ue group mobility

Info

Publication number: WO2021099923A1
Application number: PCT/IB2020/060790
Authority: WO
Inventors: Bernhard Wegmann; Klaus Negle; Michael JARSCHEL; Klaus Hoffmann
Original assignee: Nokia Solutions and Networks GmbH and Co KG
Current assignee: Nokia Solutions and Networks GmbH and Co KG
Priority date: 2019-11-21
Filing date: 2020-11-16
Publication date: 2021-05-27
Anticipated expiration: 2022-05-21

Abstract

An apparatus and a method are provided, the method comprising: detecting whether at least one mobile device of a group of mobile devices served by a first network element moves into an area served by a second network element, the group of mobile devices being controlled by an application linked to the first network element, establishing a connection between the second network element and the first network element, instructing the first network element to maintain control of the group of the mobile devices until all mobile devices of the group of user mobile devices have moved to the area served by the second network element, and instructing the first network element and the second network element to forward traffic related to the application via the connection until all mobile devices of the group of user mobile devices have moved to the area served by the second network element.

Description

SMF - SUPPORTED APPLICATION-SPECIFIC UE GROUP MOBILITY

Field of the Invention

The present invention relates to an apparatus, a method and a computer program product for supporting an application specific group mobility of group of mobile devices such as UEs.

Related background Art

The following meanings for the abbreviations used in this specification apply:

AF: Application Function

AMF: Access and Mobility Management Function

DNAI Data Network Access Identifier

EC: Edge Cloud

FIO: Flandover

IoT : Internet of Things

MEC: Multi-access Edge Cloud

NEF: Network exposure Function

NG: Next Generation

PCF: Policy Control Function

PDU: Packet Data Unit

PSA: PDU Session Anchor

RAN: Radio Access Network

SMF: Session Management Function

S-e/gNB : Source evolved/next generation NodeB

S-UPF: Source User Plane Function

S-EC: Source Edge Cloud

TA: Tracking Area

T-EC: Target Edge Cloud

T-e/gNB: Target evolved/next generation NodeB

T-UPF: Target User Plane Function

UE: User Equipment

UL CL: Uplink Classifier

UPF: User Plane Function

UL-CL: Uplink Classifier V2X: V ehicle-to-Every thing

Example embodiments, although not limited to this, relate to modern 5G cellular mobile communication systems enabling multi-access edge cloud (MEC) IoT applications with low-latency requirements for controlling a group of UEs which is treated as one unit, e.g., the controlling of a platoon of trucks.

In such a situation, care has to be taken when UEs of such a group are moving such that they move into an area served by a different MEC unit.

Summary of the Invention

Example embodiments of the present invention address this situation and aim to provide measures to enable a smooth control of a group of UEs even when the group moves into an area served by a different MEC unit.

According to a first aspect, an apparatus is provided which comprises at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform: detecting whether at least one mobile device of a group of mobile devices served by a first network element moves into an area served by a second network element, the group of mobile devices being controlled by an application linked to the first network element, establishing a connection between the second network element and the first network element, instructing the first network element to maintain control of the group of the mobile devices by the application linked to the first network element until ah mobile devices of the group of user mobile devices have moved to the area served by the second network element, and instructing the first network element and the second network element to forward traffic related to the application via the connection until all mobile devices of the group of user mobile devices have moved to the area served by the second network element.

According to a second aspect, a method is provided which comprises: detecting whether at least one mobile device of a group of mobile devices served by a first network element moves into an area served by a second network element, the group of mobile devices being controlled by an application linked to the first network element, establishing a connection between the second network element and the first network element, instructing the first network element to maintain control of the group of the mobile devices by the application linked to the first network element until all mobile devices of the group of user mobile devices have moved to the area served by the second network element, and instructing the first network element and the second network element to forward traffic related to the application via the connection until all mobile devices of the group of user mobile devices have moved to the area served by the second network element.

The first and second aspects may be modified as follows:

The connection between the second network element and the first network element may be released after all mobile devices of the group of mobile devices have moved to the area served by the second network element.

The application may be relocated from the first network element to the second network element after all mobile devices of the group of mobile devices have moved to the area served by the second network element.

It may be detected whether the at least one mobile device moving into the area served by the second network element is a mobile device of the group of mobile devices by receiving a message including information about the group of the mobile devices upon before selecting a network element for serving the mobile device.

The connection between the second network element and the first network element may be established by instructing the first network element and the second network element to establish the connection via an interface defined between the network elements.

The first network element and the second network element may perform a user plane function with respect to the mobile devices.

The application may be carried out in an edge cloud unit linked to the first network element until all mobile devices of the group of mobile devices have moved to the area served by the second network element, and the application may be carried out in an edge cloud unit linked to the second network element after all mobile devices of the group of mobile devices have moved to the area served by the second network element. According to a third aspect, an apparatus, in a first network element, is provided, the apparatus comprising: at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform: establishing a connection to a second network element based on an instruction received from a network control device, maintaining control of a group of mobile devices by an application linked to the first network element until all mobile devices of the group of the mobile devices have moved from an area served by the first network element to an area served by the second network element, and forwarding traffic concerning the group of mobile devices related to an application linked to the first network control element via the connection until all mobile devices of the group of mobile devices have moved to the area served by the second network element.

According to a fourth aspect, a method, in a first network element, is provided, the method comprising: establishing a connection to a second network element based on an instruction received from a network control device, maintaining control of a group of mobile devices by an application linked to the first network element until all mobile devices of the group of the mobile devices have moved from an area served by the first network element to an area served by the second network element, and forwarding traffic concerning the group of mobile devices related to an application linked to the first network control element via the connection until all mobile devices of the group of mobile devices have moved to the area served by the second network element.

The third and fourth aspects may be modified as follows:

The connection to the second network element may be released after all mobile devices of the group of mobile devices have moved to the area served by the second network element.

The connection to the second network element may be released based on an instruction received from the network control device.

The application may be relocated from the first network element to the second network element based on an instruction received from the network control device. The first network element may be configured to perform a user plane function with respect to the mobile devices.

The application may be carried out in an edge cloud unit linked to the first network element until all mobile devices of the group of mobile devices have moved to the area served by the second network element.

According to a fifth aspect, an apparatus, in a second network element, is provided, the apparatus comprising: at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform: establishing a connection to a first network element based on an instruction received from a network control device, and forwarding traffic concerning a group of mobile devices related to an application linked to the first network control element via the connection until all mobile devices of the group of user mobile devices have moved to the area served by the second network element.

According to a sixth aspect, a method, in a second network element, is provided, the method comprising: establishing a connection to a first network element based on an instruction received from a network control device, and forwarding traffic concerning a group of mobile devices related to an application linked to the first network control element via the connection until all mobile devices of the group of user mobile devices have moved to the area served by the second network element.

The fifth and sixth aspects may be modified as follows:

The connection to the first network element may be released after all mobile devices of the group of mobile devices have moved to the area served by the second network element.

The connection to the first network element may be released based on an instruction received from the network control device.

The application may be relocated from the first network element to the second network element after all mobile devices of the group of mobile devices have moved to the area served by the second network element. The application may be relocated from the first network element to the second network element based on an instruction received from the network control device.

The second network element may perform a user plane function with respect to the mobile devices.

The application may be carried out in an edge cloud unit linked to the second network element after all mobile devices of the group of mobile devices have moved to the area served by the second network element.

According to a seventh aspect of the present invention a computer program product is provided which comprises code means for performing a method according to any one of the second, fourth and sixth aspects and/or their modifications when run on a processing means or module. The computer program product may be embodied on a computer-readable medium, and/or the computer program product may be directly loadable into the internal memory of the computer and/or transmittable via a network by means of at least one of upload, download and push procedures.

According to an eighth aspect an apparatus is provided, which comprises means for detecting whether at least one mobile device of a group of mobile devices served by a first network element moves into an area served by a second network element, the group of mobile devices being controlled by an application linked to the first network element, means for establishing a connection between the second network element and the first network element, means for instructing the first network element to maintain control of the group of the mobile devices by the application linked to the first network element until all mobile devices of the group of user mobile devices have moved to the area served by the second network element, and means for instructing the first network element and the second network element to forward traffic related to the application via the connection until all mobile devices of the group of user mobile devices have moved to the area served by the second network element.

According to a ninth aspect an apparatus is provided, which comprises means for establishing a connection to a second network element based on an instruction received from a network control device, means for maintaining control of a group of mobile devices by an application linked to the first network element until all mobile devices of the group of the mobile devices have moved from an area served by the first network element to an area served by the second network element, and means for forwarding traffic concerning the group of mobile devices related to an application linked to the first network control element via the connection until all mobile devices of the group of mobile devices have moved to the area served by the second network element.

According to a tenth aspect an apparatus is provided, which comprises means for establishing a connection to a first network element based on an instruction received from a network control device, and forwarding traffic concerning a group of mobile devices related to an application linked to the first network control element via the connection until all mobile devices of the group of user mobile devices have moved to the area served by the second network element.

These and other objects, features, details and advantages will become more fully apparent from the following detailed description of example embodiments of the present invention which is to be taken in conjunction with the appended drawings, in which:

Fig. 1A shows an SMF 1 according to an example embodiment,

Fig. IB shows a method carried out by the SMF 1 according to the example embodiment,

Fig. 2A shows a source UPF 2 according to an example embodiment,

Fig. 2B shows a method carried out by the source UPF 2 according to the example embodiment, Fig. 3A shows a target UPF 3 according to an example embodiment,

Fig. 3B shows a method carried out by the target UPF 3 according to the example embodiment,

Fig. 4 shows a group of mobile devices UE1 to UE3 served by a source UPF before moving to an area served by a target UPF,

Fig. 5 shows the group of mobile devices UE1 to UE3 being served by the source UPF and by the target UPF after one mobile device UE3 has moved to the area served by the target UPF,

Fig. 6 illustrates re-routing to previous UPF via N9 according to an example embodiment, Fig. 7 illustrates that the detour and usage of previous UPF is kept until all UEs of group are in the serving area of the new UPF according to the example embodiment,

Fig. 8 illustrates releasing of the detour and routing the application traffic to closely linked EC in combination with application relocation according the example embodiment,

Fig. 9 illustrates a roaming 5G system architecture - local breakout scenario in a reference point (Fig. 4.2.4-4 of 3GPP 5G TS 23.501),

Fig. 10 illustrates a roaming 5G system architecture - home routed scenario in reference point representation (Fig. 4.2.4-6 of 3GPP 5G TS 23.501),

Fig. 11 illustrates a non-roaming architecture for Network Exposure Function in reference point (Fig. 4.2.3-5 of 3GPP 5G TS 23.501),

Fig. 12 illustrates processing AF requests to influence traffic routing for Sessions not identified by a UE address (Fig. 4.3.6.2-1 of TS 23.502),

Fig. 13 illustrates a notification of user plane management event (Fig. 4.3.6.3-1 of TS 23.502),

Fig. 14 illustrates a simultaneous change of Branching Point or UL-CL and additional PSA for a PDU Session (Fig. 4.3.5.7-1 of TS 23.502),

Fig. 15 illustrates an inter NG-RAN node N2 based handover, preparation phase (Fig. 4.9.1.3.2-1 of TS 23.502),

Fig. 16 illustrates an inter NG-RAN node N2 based handover, execution phase (Fig. 4.9.1.3.3-1 of TS 23.502), and

Fig. 17 illustrates a home routed roaming 5G system architecture for V2X communication over PC5 and Uu reference points - home routed scenario (Fig. 4.2.1.2-2 of TS 23.287).

Detailed Description of example embodiments In the following, description will be made to example embodiments of the present invention. It is to be understood, however, that the description is given by way of example only, and that the described example embodiments are by no means to be understood as limiting the present invention thereto.

Before describing example embodiments in detail, the problem underlying the present application is described in some more detail.

As mentioned above, some example embodiments, although not limited to this, relate to multi-access edge cloud (MEC) IoT applications with low-latency requirements for controlling a group of UEs which is treated as one unit, e.g., the controlling of a platoon of trucks.

Even though the UEs making up the group may be subscribed to different operators, the entire group has to communicate with one common application at the edge which could either be hosted by one of the operators or a third party. In order to fulfil the delay requirements for communication between group members and the application, the application should move jointly with the group, i.e., the application instance must be moved to another edge computing (EC) platform in order to maintain the low-latency conditions.

The problem description is based on the automotive use case “platooning” where several trucks are grouped to together into one unit and are communicating with, e.g., a MEC-based application. In general, it could be any group of users which may even belong to different operators (roaming is possible) and must be associated to an application with a common context. The problem exists also without the multi-operator aspect, but the multi-operator case provides more opportunities of latency-optimized UPF / EC changes.

The problem results from the fact that the UEs making up a platoon are typically spatially farther separated than the spatial decorrelation distance of the 2D slow fading (or shadowing) situation, i.e., the radio links of at least two UEs (namely with high probability for the first and last truck) belonging to the platoon (user group) require independent radio triggered cell changes / handovers. Therefore, it can happen that at least one UE is connected to a different cell than the other UEs, and thus to another group of cells being linked to another UPF / EC unit which provides a better latency range with the dedicated application instance, e.g., located on a MEC host connected to the UPF. If the cells serving the platoon are associated to one and the same UPF / MEC unit, the application works properly as shown in Fig. 4. In particular, Fig. 4 illustrates an example, in which a movement of a group (platoon) of trucks is illustrated, which moves in the diagram from left to right (as indicated by times tO, tl and t2). The trucks are examples for group UEs, and are denoted by UE1, UE2 and UE3. Two UPF /MEC units are shown, the first unit comprising an UPF U1 and an edge cloud (MEC) ECl, and the second unit comprising an UPF U2 and an edge cloud (MEC) EC2. In this example, it is assumed that the edge clouds ECl and EC2 are operated by two different operators Opl and Op2. The first UPF U1 serves an area served by base stations (eNBs) Ul-Bl and U1-B2, and the second UPF U2 serves an area served by base stations (eNBs) U2-B1 and U2-B2.

As mentioned above, in the situation shown in Fig. 4, at the time tl, the application hosted on the edge cloud of operator Opl provides the shortest distance to control the complete platoon.

The situation changes as shown in Fig. 5 for an exemplary time instance t2, where one truck (UE), namely UE3, needs to be served by a cell (U2-B1) which is linked to another UPF/MEC unit (U2 and EC2) that may even be under the management of a different operator. Since the network is per se application-agnostic and the radio-triggered handover of each UE is very time-sensitive and has to be triggered individually for each UE, the problem of MEC application consistency arises.

The Radio Access Network (RAN) does not know that certain UEs belong to a group, which means that each UE is treated individually. This means that a new application instance will be created in the new UPF / MEC unit and the UE is assigned to this application, which causes the problem addressed here. Namely, that the application context of the platoon is split, and the platoon is associated to two separate application instances. This in turn leads to high complexity in keeping the state of the two application in sync with a milli-second resolution. For one plain single UE that is not part of a platoon, this is not a problem. However, this leads to the unwanted and unfavourable scattering of the UEs’ contexts of the application across different edge cloud locations. Therefore, an application specific group handover is needed which guarantees that the group is always associated to one single MEC-App which meets the required latency threshold.

The focus of example embodiments is not on group handover but on ensuring that group of UEs served and controlled from one single application instance remains controlled from one single edge cloud application during UE mobility while still fulfilling the latency requirements. Hereto, the path switching on core network side has to be considered.

The corresponding core network aspects of the 5G system (5GS) are specified in 3GPP 5G TS 23.501. In the following, some excerpts of the standard related to some example embodiments are briefly described. These excerpts show the 5GS architecture which provides means which allows forwarding data from one UPF and UPF (interface N9), in order to be able to change radio cells while staying with the UPF. Furthermore, the capability of core functions (e.g. AF) in terms of traffic routing is briefly recapped, showing that quite some mechanisms to tackle this problem are already existing. However, a holistic method which ensures keeping a group of UEs assigned to one MEC which is linked to a particular UPF is missing. The instruction on how to use it is topic of this invention. In particular, Fig. 9 illustrates a roaming 5G system architecture - local breakout scenario in a reference point (Fig. 4.2.4-4 of 3GPP 5G TS 23.501), and Fig. 10 illustrates a roaming 5G system architecture - home routed scenario in reference point representation (Fig. 4.2.4-6 of 3GPP 5G TS 23.501). The following table is Table 5.6.7-1: Information element contained in AF request, of chapter 5.6.7 "Application Function influence on traffic routing" of 3GPP 5G TS 23.501.

It is noted that DNAI (Data Network Access Identifier) is representing potential location of application.

NEF (Network Exposure Function) allows the exposure of capabilities and events, like location of the UEs and/or group of UEs via the interface N33, as shown in Fig. 11. Fig. 11 illustrates a non roaming architecture for Network Exposure Function in reference point (Fig. 4.2.3-5 of 3GPP 5G TS 23.501).

Fig. 12 illustrates processing AF requests to influence traffic routing for Sessions not identified by a UE address (Fig. 4.3.6.2-1 of TS 23.502). Fig. 13 illustrates a notification of user plane management event (Fig. 4.3.6.3-1 of TS 23.502). Fig. 14 illustrates a simultaneous change of Branching Point or UF-CF and additional PSA for a PDU Session (Fig. 4.3.5.7-1 of TS 23.502). Fig. 15 illustrates an inter NG-RAN node N2 based handover, preparation phase (Fig. 4.9.1.3.2-1 of TS 23.502). Fig. 16 illustrates an inter NG-RAN node N2 based handover, execution phase (Fig. 4.9.1.3.3-1 of TS 23.502).

Fig. 17 illustrates a roaming 5G system architecture for V2X communication over PC5 and Uu reference points - home routed scenario. This is taken from Fig. 4.2.1.2-2 of TS 23.287 Architecture enhancements for 5G System (5GS) to support Vehicle-to-Everything (V2X) services (Release 16).

In the following, a general overview of some example embodiments is described by referring to Figs. 1A, 1B. 2A, 2B, 3 A and 3B.

Fig. 1 A shows an SMF 1 as an example for a network control device according to the present example embodiment. The network control device may be a device such as a session management function (SMF), but can be any kind of network control device capable of carrying out the functions described in the following. A procedure carried out by the SMF 1 is illustrated in Fig. IB.

The SMF 1 comprises at least one processor 11 and at least one memory 12 including computer program code. The at least one processor 11, with the at least one memory 12 and the computer program code, is configured to cause the apparatus to perform: detecting (as shown in Sll of Fig. IB) whether at least one mobile device (e.g., a UE) of a group of mobile devices (e.g., UEs) served by a first network element (e.g., source UPF 2 shown in Fig. 2A) moves into an area served by a second network element (e.g., target UPF 3 shown in Fig. 3 A), the group of mobile devices being controlled by an application linked to the first network element, establishing (as shown in S12 of Fig. IB) a connection between the second network element and the first network element, instructing (as shown in S13 of Fig. IB) the first network element to maintain control of the group of the mobile devices by the application linked to the first network element until all mobile devices of the group of user mobile devices have moved to the area served by the second network element, and instructing (as shown in S14 of Fig. IB) the first network element and the second network element to forward traffic related to the application via the connection until all mobile devices of the group of user mobile devices have moved to the area served by the second network element.

Fig. 2A shows a source user plane function (UPF) 2 as an example for a first network element according to the present example embodiment. The first network element is not limited to a user plane function but may be any suitable network element capable of carrying out the corresponding functions. A procedure carried out by the source UPF 2 is illustrated in Fig. 2B.

The UPF 2 comprises at least one processor 21 and at least one memory 22 including computer program code. The at least one processor 21, with the at least one memory 22 and the computer program code, is configured to cause the apparatus to perform: establishing (as shown in S21 of Fig. 2B) a connection to a second network element (e.g., target UPF shown in Fig. 3A) based on an instruction received from a network control device (e.g., the SMF 1 shown in Fig. 1A), maintaining control (as shown in S22 of Fig. 2B) of a group of mobile devices by an application linked to the first network element until all mobile devices of the group of the mobile devices have moved from an area served by the first network element to an area served by the second network element, and forwarding (as shown in S23 of Fig. 2B) traffic concerning the group of mobile devices related to an application linked to the first network control element via the connection until all mobile devices of the group of mobile devices have moved to the area served by the second network element.

Fig. 3A shows a target UPF 3 as an example for a second network element according to the present example embodiment. The second network element may be a user plane function, or any other suitable network element capable of carrying out the corresponding functions. A procedure carried out by the target UPF 3 is illustrated in Fig. 3B.

The UPF 3 comprises at least one processor 31 and at least one memory 32 including computer program code. The at least one processor 31, with the at least one memory 32 and the computer program code, is configured to cause the apparatus to perform: receiving (as shown in S31 of Fig. 3B) an instruction from a network control device (e.g., the SMF 1 shown in Fig. 1A) to establish a connection to a first network element (e.g., the source UPF 2 shown in Fig. 2A), and forwarding (as shown in S32 of Fig. 3B) traffic concerning a group of mobile devices related to an application linked to the first network control element via the connection until all mobile devices of the group of user mobile devices have moved to the area served by the second network element.

The SMF 1 may further comprise an I/O unit 13, which is capable of transmitting to and receiving from other network elements, the source UPF 2 may further comprise an I/O unit 23, which is capable of transmitting to and receiving from other network elements, and, likewise, the target UPF 3 may further comprise an I/O unit 33, which is cable of transmitting to and receiving from network elements.

The connection between the target UPF 3 (the second network element) and the source UPF 2 (the first network element) may be released after all mobile devices of the group of mobile devices have moved to the area served by the second network element. Releasing the connection may be carried out based on an instruction sent from the SMF 1 to the UPFs 2 and 3. The application may be relocated from the source UPF 2 (first network element) to the target UPF 3 (the second network element) after all mobile devices of the group of mobile devices have moved to the area served by the second network element. The relocation of the application may be performed based on an instruction sent either from the SMF 1 to the UPFs 2 and 3 or from the AF via the SMF 1 to the UPFs 2 and 3. The application may be carried out in an edge cloud unit linked to the source UPF 2 (the first network element) until all mobile devices of the group of mobile devices have moved to the area served by the target UPF 3 (the second network element), and the application may be carried out in an edge cloud unit linked to the second network element after all mobile devices of the group of mobile devices have moved to the area served by the second network element.

Thus, according to example embodiments, the following advantages are achieved: it is possible to maintain control of a group of mobile devices by the application linked to the first (source) network element (source UPF) until all mobile devices of the group of mobile devices have moved to the area served by the second (target) network element. In this way, advantageously, it is ensured that also applications with low-latency requirements with respect to the group of mobile devices may be reliably carried out.

In the following, this is further described by referring to some further detailed embodiments.

According to some example embodiments, a new procedure is proposed which ensures an “en bloc” relocation of a group of UEs contexts between two edge cloud (EC) instances of a stateful application they are associated to. This is achieved by re-routing of the UPF-EC linkage via the N9 interface when at least one UE of the group has been already handed over to a radio cell served by another UPF, which belongs to another UPF serving area (as shown in Fig. 6 described in the following). For this purpose, a UE group location information regarding the UPF serving area is used to instruct the newly connected UPF to establish a route via the N9 interface to the UPF linked to the edge cloud hosting the application instance that the remaining UEs of the group are associated to. This “detour” remains established until all UEs of the group are served by new UPF (as shown in Fig. 7 described in the following). Then, application (state) movement to the new hosting EC, linked to new UPF, is carried out in combination with a path switch to the new hosting EC and release of the N9 interface connection (as shown in Fig. 8 described in the following).

The procedure described above is described in the following by referring to Figs. 6 to 8 as described above. The basic scenario is similar to that as described above with respect to Figs. 4 and 5. That is, a movement of a group (platoon) of trucks denoted by UE1 to UE3 is illustrated, wherein a first area including two cells served by base stations Ul-Bl and U1-B2 is served by a first UPF Ul, and a second area including two cells served by base stations U2-B 1 and U2-B2 is served by a second UPF U2. The UPFs Ul and U2 are linked to edge clouds ECl and EC2, respectively.

As shown in Fig. 6, the truck UE3 has made a handover from U1-B2 to U2-B1 and is thus in an area served by the UPF U2. According to the present embodiment, a re-routing to the previous UPF Ul via N9 is performed. As shown in Fig. 7, the detour and usage of the previous UPF Ul is kept until all UEs of the group are in the serving area of the new UPF U2. As shown in Fig. 8, after all UEs of the group are in the serving area of the new UPF U2, the detour is released and the application traffic is now routed to the closely linked EC (EC2) in combination with the application relocation.

In the following, some more details of example embodiments are described.

According to the example embodiments, it is suggested that some parts of the group application re allocation shall be performed via a new cooperation procedure between the AF and the mobile core (e.g. SMF), where the core network topology connects during the handover process the source e/gNB (S-e/gNB) (e.g. U1-B2) via the source UPF (S-UPF) (e.g., Ul) to the source EC (S-EC) (e.g., ECl), but the target e/gNB (T-e/gNB) (e.g. U2-B1) via the target UPF (T-UPF) (e.g., U2) to the target EC (T-EC) (e.g., EC2). This implies the usage of the N2 handover procedure as described in chapter 4.9.1.2.3 of TS 23502.

Even though one UE of the group has been handed over to a RAN area linked to the new T-UPF, the application instance associated with the UE group is kept in the previous S-UPF / S-EC, as described above with respect to Figs. 6 to 8. This requires intervening already during the UE handover procedure to simultaneously consider the need to have a new UPF acting as the UL-CL UPF due to split of the UE group into different RAN areas, until all group UEs are handed over to the T-e/gNBs assigned to the T-UPF.

Based on the existing chart, as already specified in TS 23.502 Figure 4.9.1.3.2-1. (N2 HO preparation), as shown in Fig. 15, it is suggested that the SMF on receipt of the message “Nsmf_PDUSession_UpdateSMContext“ in procedure 4 for the selection of the UPF in procedure 5 shall check whether the involved UE is a member of, e.g., a “platoon group” or rather more generalized a member of an application group, which requires synchronized re-allocation of the group application.

If the UE is not member of such an application group, the SMF starts selection and relocation/insertion of UL-CL UPF and EC as before. See clarification in chapter 4.3.5.7. of TS 23502 VI 6.1.0 that UL-CL and PSA can be changed during Xn HO, N2 HO and service request procedure simultaneously.

That means that for the T-e/gNB the corresponding T-UPF and UL-CL UPF is selected and connected to the old PSA UPF anchor to reach the old S-EC and simultaneously reach the T-EC from the UL-CL PSA2 by splitting/merging of traffic to/from S-EC and T-EC. Since the T-e/gNB is associated with T-EC, the T-UPF/UL-CL is to be inserted to reach the new T-EC and to reach the old S-EC via S-UPF. For a single UE there is no need for synchronized group application relocation.

However, if the SMF detects that the UE is a member of an application group (e.g. a platoon), the SMF shall suppress the insertion of the UL-CL UPF, and suppress the split of the traffic to the T-EC and suppress the merging of traffic from the T-EC at the UL-CL UPF, until all the UEs of the platoon are reaching the application at the old S-EC via the T-UPF. In that case, instead the SMF shall either insert the UL-CL UPF but without splitting/merging the traffic via filtering rules or without activating the UL-CL functionality at all. However, only after all the UEs of the application group (platoon) are connected via T-UPF and S-UPF with the application at S-EC , the SMF shall modify the filtering rules or activate ULCL functionality for all UEs of the group in order to relocate from S-UPF/S-EC to T-UPF/T-EC in accordance with the existing AF early/late notification procedure for a coordinated synchronized relocation of group application and UPFs.

According to an alternative example embodiment, a more recent version of TS23.502 is considered, in which in chapter 4.3.5.7 the insertion of the UL-CL during N2 HO procedure is deprecated and it is now recommended to relocate the application simply after the handover procedure has been successfully completed.

In that case, according to the alternative example embodiment, it is suggested that a corresponding new solution shall look like the following: Since the newly recommended/specified procedure in the TS 23.502 does not split (/merge) the traffic during the execution of the handover procedure at all, there is no need to suppress any traffic towards the T-EC at all. However, the SMF needs to keep track of all UEs to only start the relocation from the S-UPF to the T-UPF, once all UEs have connectivity with S-EC from the T-e/gNB.

The above-described example embodiments are only examples and may be modified.

For example, some of the example embodiments were described in the framework of 5G cellular mobile communication system. However, procedures described above can be applied to any kind of cellular mobile communication system in which a group of mobile devices may move between an area served by a first network element to an area served by a second network element.

According to example embodiments described above, the SMF instructs the source UPF to release the connection after all UEs have moved to the target UPF. For this, the SMF may subscribe to the AMF to get notified about new location of the UEs (gNB ID, TA (Tracking area, etc ). The SMF decides on the UPF, based on handling of UPF relocation, change, and release of the UPF. The existing 5G procedures already notify the AF about new location of the UPF. The SMF notifies the AF about the fact that it is now save to relocate all the contexts of the Group. Then, after the AF has been notified about the association of the complete group at the UPF, the AF may initiate the relocation of the contexts. However, example embodiments are not limited to this. For example, the source UPF (first network element) and/or the target UPF (second network element) may detect that all UEs have moved to the area served by the target UPF, and may then release the connection, and may also relocate the application.

Thus, according to example embodiments, the following advantages are achieved:

According to example embodiments, an application specific group handover or movement between two areas served by different UPFs is provided, which guarantees that the group is always associated to one single MEC-App which meets the required latency threshold. Thus, it is possible to maintain control of a group of mobile devices by the application linked to the first (source) network element (source UPF) until all mobile devices of the group of mobile devices have moved to the area served by the second (target) network element. In this way, it is ensured that also applications with low- latency requirements with respect to the group of mobile devices may be reliably carried out.

Names of network elements, protocols, and methods are based on current standards. In other versions or other technologies, the names of these network elements and/or protocols and/or methods may be different, as long as they provide a corresponding functionality.

In general, the example embodiments may be implemented by computer software stored in the memory (memory resources, memory circuitry) 12, 22, 32 and executable by the processor (processing resources, processing circuitry) 11, 21, 31 or by hardware, or by a combination of software and/or firmware and hardware.

As used in this application, the term "circuitry" refers to all of the following:

(a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and

(b) to combinations of circuits and software (and/or firmware), such as (as applicable): (i) to a combination of processor(s) or (ii) to portions of processor(s)/software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and

(c) to circuits, such as a microprocessor s) or a portion of a microprocessor(s), that require software or firmware for operation, even if the software or firmware is not physically present.

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

The terms "connected," "coupled," or any variant thereof, mean any connection or coupling, either direct or indirect, between two or more elements, and may encompass the presence of one or more intermediate elements between two elements that are "connected" or "coupled" together. The coupling or connection between the elements can be physical, logical, or a combination thereof. As employed herein two elements may be considered to be "connected" or "coupled" together by the use of one or more wires, cables and printed electrical connections, as well as by the use of electromagnetic energy, such as electromagnetic energy having wavelengths in the radio frequency region, the microwave region and the optical (both visible and invisible) region, as non-limiting examples. The memory (memory resources, memory circuitry) 12, 22, 32 may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory, and non-transitory computer- readable media. The processor (processing resources, processing circuitry) 11, 21, 31 may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on a multi core processor architecture, as non-limiting examples.

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

Claims

1. An apparatus, comprising: at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform: detecting whether at least one mobile device of a group of mobile devices served by a first network element moves into an area served by a second network element, the group of mobile devices being controlled by an application linked to the first network element, establishing a connection between the second network element and the first network element, instructing the first network element to maintain control of the group of the mobile devices by the application linked to the first network element until all mobile devices of the group of user mobile devices have moved to the area served by the second network element, and instructing the first network element and the second network element to forward traffic related to the application via the connection until all mobile devices of the group of user mobile devices have moved to the area served by the second network element.

2. The apparatus according to claim 1 , wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to further perform: releasing the connection between the second network element and the first network element after all mobile devices of the group of mobile devices have moved to the area served by the second network element.

3. The apparatus according to claim 1 or 2, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to further perform: relocating the application from the first network element to the second network element after all mobile devices of the group of mobile devices have moved to the area served by the second network element.

4. The apparatus according to any one of the claims 1 to 3, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to further perform: detecting whether the at least one mobile device moving into the area served by the second network element is a mobile device of the group of mobile devices by receiving a message including information about the group of the mobile devices upon before selecting a network element for serving the mobile device.

5. The apparatus according to any one of the claims 1 to 4, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to further perform: establishing the connection between the second network element and the first network element by instructing the first network element and the second network element to establish the connection via an interface defined between the network elements.

6. The apparatus according to any one of the claims 1 to 5, wherein the first network element and the second network element are configured to perform a user plane function with respect to the mobile devices.

7. The apparatus according to claim 6, wherein the application is carried out in an edge cloud unit linked to the first network element until all mobile devices of the group of mobile devices have moved to the area served by the second network element, and the application is carried out in an edge cloud unit linked to the second network element after all mobile devices of the group of mobile devices have moved to the area served by the second network element.

8. An apparatus, in a first network element, comprising: at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform: establishing a connection to a second network element based on an instruction received from a network control device, maintaining control of a group of mobile devices by an application linked to the first network element until all mobile devices of the group of the mobile devices have moved from an area served by the first network element to an area served by the second network element, and forwarding traffic concerning the group of mobile devices related to an application linked to the first network control element via the connection until all mobile devices of the group of mobile devices have moved to the area served by the second network element.

9. The apparatus according to claim 8, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to further perform: releasing the connection to the second network element after all mobile devices of the group of mobile devices have moved to the area served by the second network element.

10. The apparatus according to claim 8 or 9, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to further perform: releasing the connection to the second network element based on an instruction received from the network control device.

11. The apparatus according to any one of the claims 8 to 10, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to further perform: relocating the application from the first network element to the second network element after all mobile devices of the group of mobile devices have moved to the area served by the second network element.

12. The apparatus according to any one of the claims 8 to 11 , wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to further perform: relocating the application from the first network element to the second network element based on an instruction received from the network control device.

13. The apparatus according to any one of the claims 8 to 12, wherein the first network element is configured to perform a user plane function with respect to the mobile devices.

14. The apparatus according to claim 13, wherein the application is carried out in an edge cloud unit linked to the first network element until all mobile devices of the group of mobile devices have moved to the area served by the second network element.

15. An apparatus, in a second network element, comprising: at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform: establishing a connection to a first network element based on an instruction received from a network control device, and forwarding traffic concerning a group of mobile devices related to an application linked to the first network control element via the connection until all mobile devices of the group of user mobile devices have moved to the area served by the second network element.

16. The apparatus according to claim 15, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to further perform: releasing the connection to the first network element after all mobile devices of the group of mobile devices have moved to the area served by the second network element.

17. The apparatus according to claim 15 or 16, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to further perform: releasing the connection to the first network element based on an instruction received from the network control device.

18. The apparatus according to any one of the claims 15 to 17, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to further perform: relocating the application from the first network element to the second network element after all mobile devices of the group of mobile devices have moved to the area served by the second network element.

19. The apparatus according to any one of the claims 15 to 18, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to further perform: relocating the application from the first network element to the second network element based on an instruction received from the network control device.

20. The apparatus according to any one of the claims 15 to 19, wherein the second network element is configured to perform a user plane function with respect to the mobile devices.

21. The apparatus according to claim 20, wherein the application is carried out in an edge cloud unit linked to the second network element after all mobile devices of the group of mobile devices have moved to the area served by the second network element.

22. A method, comprising: detecting whether at least one mobile device of a group of mobile devices served by a first network element moves into an area served by a second network element, the group of mobile devices being controlled by an application linked to the first network element, establishing a connection between the second network element and the first network element, instructing the first network element to maintain control of the group of the mobile devices by the application linked to the first network element until all mobile devices of the group of user mobile devices have moved to the area served by the second network element, and instructing the first network element and the second network element to forward traffic related to the application via the connection until all mobile devices of the group of user mobile devices have moved to the area served by the second network element.

23. The method according to claim 22, further comprising: releasing the connection between the second network element and the first network element after all mobile devices of the group of mobile devices have moved to the area served by the second network element.

24. The method according to claim 22 or 23, further comprising: relocating the application from the first network element to the second network element after all mobile devices of the group of mobile devices have moved to the area served by the second network element.

25. The method according to any one of the claims 22 to 24, further comprising: detecting whether the at least one mobile device moving into the area served by the second network element is a mobile device of the group of mobile devices by receiving a message including information about the group of the mobile devices upon before selecting a network element for serving the mobile device.

26. The method according to any one of the claims 22 to 25, further comprising: establishing the connection between the second network element and the first network element by instructing the first network element and the second network element to establish the connection via an interface defined between the network elements.

27. The method according to any one of the claims 22 to 26, wherein first the network element and the second network element perform a user plane function with respect to the mobile devices.

28. The method according to claim 27, wherein the application is carried out in an edge cloud unit linked to the first network element until all mobile devices of the group of mobile devices have moved to the area served by the second network element, and the application is carried out in an edge cloud unit linked to the second network element after all mobile devices of the group of mobile devices have moved to the area served by the second network element.

29. A method, in a first network element, comprising: establishing a connection to a second network element based on an instruction received from a network control device, maintaining control of a group of mobile devices by an application linked to the first network element until all mobile devices of the group of the mobile devices have moved from an area served by the first network element to an area served by the second network element, and forwarding traffic concerning the group of mobile devices related to an application linked to the first network control element via the connection until all mobile devices of the group of mobile devices have moved to the area served by the second network element.

30. The method according to claim 29, further comprising: releasing the connection to the second network element after all mobile devices of the group of mobile devices have moved to the area served by the second network element.

31. The method according to claim 29 or 30, further comprising: releasing the connection to the second network element based on an instruction received from the network control device.

32. The method according to any one of the claims 29 to 31, further comprising: relocating the application from the first network element to the second network element after all mobile devices of the group of mobile devices have moved to the area served by the second network element.

33. The method according to any one of the claims 29 to 32, further comprising: relocating the application from the first network element to the second network element based on an instruction received from the network control device.

34. The method according to any one of the claims 29 to 33, wherein the first network element is configured to perform a user plane function with respect to the mobile devices.

35. The method according to claim 34, wherein the application is carried out in an edge cloud unit linked to the first network element until all mobile devices of the group of mobile devices have moved to the area served by the second network element.

36. A method, in a second network element, comprising: establishing a connection to a first network element based on an instruction received from a network control device, and forwarding traffic concerning a group of mobile devices related to an application linked to the first network control element via the connection until all mobile devices of the group of user mobile devices have moved to the area served by the second network element.

37. The method according to claim 36, further comprising: releasing the connection to the first network element after all mobile devices of the group of mobile devices have moved to the area served by the second network element.

38. The method according to claim 36 or 37, further comprising: releasing the connection to the first network element based on an instruction received from the network control device.

39. The method according to any one of the claims 36 to 38, further comprising: relocating the application from the first network element to the second network element after all mobile devices of the group of mobile devices have moved to the area served by the second network element.

40. The method according to any one of the claims 36 to 39, further comprising: relocating the application from the first network element to the second network element based on an instruction received from the network control device.

41. The method according to any one of the claims 36 to 40, wherein the second network element performs a user plane function with respect to the mobile devices.

42. The method according to claim 41, wherein the application is carried out in an edge cloud unit linked to the second network element after all mobile devices of the group of mobile devices have moved to the area served by the second network element.

43. A computer program product comprising code means for performing a method according to any one of the claims 22 to 42, when run on a processing means or module.

44. The computer program product according to claim 43, wherein the computer program product is embodied on a computer-readable medium, and/or the computer program product is directly loadable into the internal memory of the computer and/or transmittable via a network by means of at least one of upload, download and push procedures.