WO2021038277A1

WO2021038277A1 - Broadcast service

Info

Publication number: WO2021038277A1
Application number: PCT/IB2019/057263
Authority: WO
Inventors: Péter SZILÁGYI
Original assignee: Nokia Technologies Oy
Priority date: 2019-08-28
Filing date: 2019-08-28
Publication date: 2021-03-04

Abstract

There is disclosed an apparatus. The apparatus comprises means for performing: receiving data to be broadcast and a broadcast area definition in a same user-plane packet; using the broadcast area definition to determine one or more base stations to send the broadcast data to; and sending the broadcast data to the one or more base stations.

Description

BROADCAST SERVICE

Field

This disclosure relates to communications, and more particularly to communications in a wireless communication system. More particularly the present disclosure relates to a programmable broadcast service for 5G.

Background

A communication system can be seen as a facility that enables communication between two or more devices such as user terminals, machine-like terminals, base stations and/or other nodes by providing communication channels for carrying information between the communicating devices. A communication system can be provided for example by means of a communication network and one or more compatible communication devices.

A communication system and associated devices typically operate in accordance with a given standard or specification which sets out what the various entities associated with the system are permitted to do and how that should be achieved. Communication protocols and/or parameters which shall be used for the connection are also typically defined. Non-limiting examples of standardised radio access technologies include GSM (Global System for Mobile), EDGE (Enhanced Data for GSM Evolution) Radio Access Networks (GERAN), Universal Terrestrial Radio Access Networks (UTRAN) and evolved UTRAN (E-UTRAN). An example communication system architecture is the long-term evolution (LTE) of the Universal Mobile Telecommunications System (UMTS) radio-access technology. The LTE is standardized by the third Generation Partnership Project (3GPP). The LTE employs the Evolved Universal Terrestrial Radio Access Network (E-UTRAN) access and a further development thereof which is sometimes referred to as LTE Advanced (LTE-A).

Since the introduction of fourth generation (4G) services, increasing interest has been paid to the next, or fifth generation (5G) standard. 5G may also be referred to as a New Radio (NR) network.

Summary

According to a first aspect, there is provided an apparatus comprising means for performing receiving data to be broadcast and a broadcast area definition in a same user-plane packet; using the broadcast area definition to determine one or more base stations to send the broadcast data to; and sending the broadcast data to the one or more base stations. According to some examples, the means are further configured to perform receiving the data to be broadcast and the broadcast area definition from an application function on an N6 user-plane connection.

According to some examples, the means are further configured to perform using the broadcast area definition to determine one or more base stations to forward the broadcast data to by obtaining base station address information.

According to some examples, the means are further configured to obtain the base station address information from an entity which stores cell identifier and base station address pairs.

According to some examples, the means are further configured to directly query the entity for the base station address information.

According to some examples the entity is stored in a local cache of the apparatus.

According to some examples, the means are further configured to query a session management function which stores the entity for the base station address information.

According to some examples the means are further configured to perform generating a list of unique base station internet protocol addresses by removing any duplicates.

According to some examples, the means are further configured to perform receiving and storing an authentication token at the apparatus.

According to some examples, the authentication token defines one or more of the following parameters: a geographical area which the broadcast data may potentially be broadcast to; a time period.

According to some examples, the means are further configured to perform checking the authentication token before sending the broadcast data to the one or more base stations.

According to some examples the broadcast data is dropped at the apparatus when there is no valid authentication token for the broadcast data.

According to some examples, the apparatus comprises a user plane function.

According to some examples, the means comprises at least one processor; and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

According to a second aspect, there is provided 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: receiving data to be broadcast and a broadcast area definition in a same user-plane packet; using the broadcast area definition to determine one or more base stations to send the broadcast data to; and sending the broadcast data to the one or more base stations.

According to some examples, the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform: receiving the data to be broadcast and the broadcast area definition from an application function on an N6 user-plane connection.

According to some examples, the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform: using the broadcast area definition to determine one or more base stations to forward the broadcast data to by obtaining base station address information.

According to some examples, the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform: obtaining the base station address information from an entity which stores cell identifier and base station address pairs.

According to some examples, the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform: directly querying the entity for the base station address information.

According to some examples, the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform: querying a session management function which stores the entity for the base station address information.

According to some examples, the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform: receiving and storing an authentication token at the apparatus.

According to some examples, the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform: checking the authentication token before sending the broadcast data to the one or more base stations.

According to some examples, the apparatus comprises a user plane function.

According to a third aspect there is provided an apparatus comprising: receiving circuitry for receiving data to be broadcast and a broadcast area definition in a same user-plane packet; using circuitry for using the broadcast area definition to determine one or more base stations to send the broadcast data to; and sending circuitry for sending the broadcast data to the one or more base stations. According to a fourth aspect there is provided a method comprising: receiving data to be broadcast and a broadcast area definition in a same user-plane packet; using the broadcast area definition to determine one or more base stations to send the broadcast data to; and sending the broadcast data to the one or more base stations.

According to some examples, the method comprises receiving the data to be broadcast and the broadcast area definition from an application function on an N6 user-plane connection.

According to some examples, the method comprises using the broadcast area definition to determine one or more base stations to forward the broadcast data to by obtaining base station address information.

According to some examples, the method comprises obtaining the base station address information from an entity which stores cell identifier and base station address pairs.

According to some examples, the method comprises directly querying the entity for the base station address information.

According to some examples, the method comprises querying a session management function which stores the entity for the base station address information.

According to some examples, the method comprises generating a list of unique base station internet protocol addresses by removing any duplicates.

According to some examples, the method comprises receiving and storing an authentication token at the apparatus.

According to some examples, the method comprises checking the authentication token before sending the broadcast data to the one or more base stations.

According to some examples, the method comprises dropping the broadcast data at the apparatus when there is no valid authentication token for the broadcast data.

According to some examples, the apparatus comprises a user plane function.

According to a fifth aspect there is provided a computer program comprising instructions for causing an apparatus to perform at least the following: receiving data to be broadcast and a broadcast area definition in a same user-plane packet; busing the broadcast area definition to determine one or more base stations to send the broadcast data to; and sending the broadcast data to the one or more base stations

According to a sixth aspect there is provided a computer program comprising instructions stored thereon for performing at least the following: receiving data to be broadcast and a broadcast area definition in a same user-plane packet; using the broadcast area definition to determine one or more base stations to send the broadcast data to; and sending the broadcast data to the one or more base stations

According to a seventh aspect there is provided a non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the following: receiving data to be broadcast and a broadcast area definition in a same user-plane packet; using the broadcast area definition to determine one or more base stations to send the broadcast data to; and sending the broadcast data to the one or more base stations

According to an eighth aspect there is provided a non-transitory computer readable medium comprising program instructions stored thereon for performing at least the following: receiving data to be broadcast and a broadcast area definition in a same user-plane packet; using the broadcast area definition to determine one or more base stations to send the broadcast data to; and sending the broadcast data to the one or more base stations.

According to a ninth aspect there is provided an apparatus comprising means for performing: sending data to be broadcast and a broadcast area definition in a same user-plane packet to a user plane function.

According to some examples, the means are further configured to perform sending the data to be broadcast and the broadcast area definition to a user-plane function on an N6 user-plane connection.

According to some examples, the broadcast area definition comprises a list of cell identifiers.

According to some examples, the means are further configured to perform obtaining an authentication token.

According to some examples the authentication token is obtained from a network exposure function.

According to some examples, the means are further configured to perform sending the authentication token to the user plane function in the same user plane packet as the data to be broadcast and the broadcast area definition. According to some examples, the apparatus comprises an application function.

According to a tenth aspect there is provided 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: sending data to be broadcast and a broadcast area definition in a same user-plane packet to a user plane function.

According to some examples, the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform: sending the data to be broadcast and the broadcast area definition to a user-plane function on an N6 user-plane connection.

According to some examples, the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform obtaining an authentication token.

According to some examples, the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform: sending the authentication token to the user plane function in the same user plane packet as the data to be broadcast and the broadcast area definition.

According to some examples, the apparatus comprises an application function.

According to an eleventh aspect, there is provided an apparatus comprising: sending circuitry for sending data to be broadcast and a broadcast area definition in a same user-plane packet to a user plane function.

According to a twelfth aspect, there is provided a method comprising: sending data to be broadcast and a broadcast area definition in a same user-plane packet to a user plane function.

According to some examples, the method comprises sending the data to be broadcast and the broadcast area definition to a user-plane function on an N6 user-plane connection.

According to some examples, the broadcast area definition comprises a list of cell identifiers. According to some examples, the method comprises obtaining an authentication token.

According to some examples, the method comprises obtaining the authentication token from a network exposure function.

According to some examples, the method comprises sending the authentication token to the user plane function in the same user plane packet as the data to be broadcast and the broadcast area definition.

According to some examples, the apparatus comprises an application function.

According to a thirteenth aspect, there is provided a computer program comprising instructions for causing an apparatus to perform at least the following: sending data to be broadcast and a broadcast area definition in a same user-plane packet to a user plane function.

According to a fourteenth aspect, there is provided a computer program comprising instructions stored thereon for performing at least the following: sending data to be broadcast and a broadcast area definition in a same user-plane packet to a user plane function.

According to a fifteenth aspect, there is provided a non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the following: sending data to be broadcast and a broadcast area definition in a same user-plane packet to a user plane function.

According to a sixteenth aspect, there is provided a non-transitory computer readable medium comprising program instructions stored thereon for performing at least the following: sending data to be broadcast and a broadcast area definition in a same user-plane packet to a user plane function.

According to a seventeenth aspect, there is provided an apparatus comprising means for performing: storing one or more cell-identifier and base station address pairs in a database; and sending a base station address to a user plane function in response to a query from the user plane function, the query comprising a cell-identifier.

According to some examples, the base station address comprises an internet protocol address.

According to some examples, the apparatus is pre-configured with the cell-identifier and base station address pairs.

According to some examples, the means are further configured to perform learning the cell- identifier and base station address pairs by collecting the information from a user equipment initiated protocol data unit session establishment procedure. According to some examples, the means are further configured to perform obtaining timestamp information during the protocol data unit session establishment procedure, and subsequently using the timestamp information to cancel cell-identifier base station address pairs which have not been used for a predetermined amount of time.

According to some examples, the apparatus comprises a session management function.

According to an eighteenth aspect, there is provided 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: storing one or more cell-identifier and base station address pairs in a database; and sending a base station address to a user plane function in response to a query from the user plane function, the query comprising a cell-identifier.

According to some examples, the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform: learning the cell- identifier and base station address pairs by collecting the information from a user equipment initiated protocol data unit session establishment procedure.

According to some examples, the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to perform: obtaining timestamp information during the protocol data unit session establishment procedure, and subsequently using the timestamp information to cancel cell-identifier base station address pairs which have not been used for a predetermined amount of time.

According to a nineteenth aspect, there is provided an apparatus comprising storing circuitry for storing one or more cell-identifier and base station address pairs in a database; and sending circuitry for sending a base station address to a user plane function in response to a query from the user plane function, the query comprising a cell-identifier. According to a twentieth aspect, there is provided a method comprising storing one or more cell-identifier and base station address pairs in a database; and sending a base station address to a user plane function in response to a query from the user plane function, the query comprising a cell-identifier.

According to some examples, the method comprises learning the cell-identifier and base station address pairs by collecting the information from a user equipment initiated protocol data unit session establishment procedure.

According to some examples, the method comprises obtaining timestamp information during the protocol data unit session establishment procedure, and subsequently using the timestamp information to cancel cell-identifier base station address pairs which have not been used for a predetermined amount of time.

According to a twenty first aspect, there is provided a computer program comprising instructions for causing an apparatus to perform at least the following: storing one or more cell-identifier and base station address pairs in a database; and sending a base station address to a user plane function in response to a query from the user plane function, the query comprising a cell-identifier.

According to a twenty second aspect, there is provided a computer program comprising instructions stored thereon for performing at least the following: storing one or more cell-identifier and base station address pairs in a database; and sending a base station address to a user plane function in response to a query from the user plane function, the query comprising a cell-identifier.

According to a twenty third aspect, there is provided a non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the following: storing one or more cell-identifier and base station address pairs in a database; and sending a base station address to a user plane function in response to a query from the user plane function, the query comprising a cell-identifier.

According to a twenty fourth aspect, there is provided a non-transitory computer readable medium comprising program instructions stored thereon for performing at least the following: storing one or more cell-identifier and base station address pairs in a database; and sending a base station address to a user plane function in response to a query from the user plane function, the query comprising a cell-identifier. It will thus be understood that embodiments provide an in-band, programmable broadcast service for 5G, provided by the UPF to an AF over the N6 interface. The in-band programmability means that the AF may send a U-plane packet to the UPF for broadcasting without any a priori control plane broadcast session establishment procedure, because the N6 interface is extended to accept packets that are self-contained combinations of the broadcast area and the broadcast data itself. As opposed to the prior art, the embodiments disclosed is an improvement in the technical field as the proposed embodiments may be fully provided within the Release- 15 5G network functions, without having to create/integrate additional ones (such as from the MBMS architecture). Also, the embodiments use 5G NR gNB instead of E-UTRA/ng-eNB in the RAN.

Brief description of Figures

Some embodiments will now be described in further detail, by way of example only, with reference to the following examples and accompanying drawings, in which:

Figure 1 shows a schematic example of 5G MBMS architecture;

Figure 2 schematically shows architecture for broadcast/multicast/group delivery;

Figure 3 schematically shows an in-band architecture according to an example;

Figure 4 is a signalling diagram showing a method according to an example;

Figure 5 schematically shows user-plane broadcast packet transmission according to an example;

Figure 6 schematically shows a user plane protocol stack according to an example;

Figure 7 is a signalling diagram schematically showing an address resolution procedure according to an example;

Figure 8 is a signalling diagram schematically showing an alternative address resolution procedure according to an example;

Figure 9 is a signalling diagram schematically showing SMF functionality according to an example;

Figure 10 is a flow-chart of a method according to an example;

Figure 11 schematically shows parts of a wireless communication device according to an example;

Figure 12 schematically shows parts of a control apparatus according to an example;

Figure 13 schematically shows a method according to an example; Figure 14 schematically shows a method according to an example;

Figure 15 schematically shows a method according to an example.

Detailed description

As briefly mentioned above, the present disclosure is related to broadcasting in 5G systems. The broadcast framework is not standardized in 5G yet. The present disclosure takes in to account a realization that there is an opportunity to develop a simple and flexible broadcast framework for 5G, rather than for example just replicating LTE eMBMS / SC-PTM (Single Cell to Multipoint) solutions.

There is a problem that Application Functions (AF), such as the V2X (Vehicle to Every thing/ Any thing) Application Server (V2X-AS), may require a combination of unicast and broadcast mode of data delivery to send information to multiple UEs efficiently. In network based V2X communication, the decision whether a given packet (V2X message) is transferred with unicast (to a dedicated UE, using dedicated UE-specific resources) or with broadcast (to multiple UEs under a given coverage area) may need to be arbitrated dynamically in real-time, on a packet-by-packet basis. Based on this requirement, it has been realised in this disclosure that the following technical problems exist in current 5G systems:

The decision about unicast or broadcast needs to be made by the V2X-AS, which is an AF.

The delivery mode (unicast or broadcast) may need to be arbitrated on a per packet level, in real-time. Due to the end-to-end low latency requirement of V2X communication, there is no time for C-plane negotiation between the V2X-AS and the rest of the 5G system when suddenly broadcast mode is required for a U-plane packet that is ready to be transferred from the V2X- AS to the 5G system.

In broadcast mode, the area (e.g., list of cells) where a given packet is to be broadcasted may need to be tailored specifically based on the content of the packet (which defines the list of UEs that need to receive the packet, and the location of those UEs further defines the geo-area of interest). Such dynamic and flexible broadcast scheme enables a single V2X-AS instance to serve and distribute V2X messages over a large area, where each message has only relevance for a unique list of other UEs and where the optimal broadcast area may change from message to message. Therefore, cell level broadcast area granularity needs to be supported by the 5G system, where a given message can be broadcasted in any combination of one or more cells. Such broadcast area granularity means that the potential number of different broadcast areas (cell groups) is extremely large. For example, each cell is a potential one member group by itself; every combination of two cells form two-member groups; every combination of three cells form additional three -member groups; etc.). This may make pre -definition of broadcast areas completely infeasible. For example, a new broadcast area would need to be defined, via C-plane (control-plane) between the V2X-AS and the 5G system, before the V2X-AS may transfer the next U-plane message).

Another technical problem is how to specify the broadcast area by the AF. According to 3GPP TS 23.285 section 4.3.3, the V2X-AS may collect Cell IDs from UEs (e.g., via the V 1 interface, that is, from the V2X application in the UE, which is out of scope of 3GPP) and thus may be aware of each UE’s location at cell level. The V2X-AS could also collect Cell IDs via the AMF’s UE mobility event notification (using the service -based interface directly or via the NEF). Fiowever, there is a question that, if the V2X-AS wanted to use the collected Cell IDs to specify the broadcast area of a given U- plane message, which network function would be able to interpret the Cell IDs and map them into specific RAN nodes (gNBs) where the broadcast should happen. In the MBMS (Multimedia Broadcast Multicast Service) architecture, the BM-SC (Broadcast-Multicast Service Centre) in principle could take Cell IDs from the V2X-AS as broadcast area specification. However, relying on BM-SC would require “lift-and-drop” replication and integration of the whole legacy MBMS architecture into 5G. Without that, it is open how the 5G system can interpret Cell IDs received from the AF and perform broadcast selectively only in the requested cells.

Figure 1 shows a potential 5G-MBMS architecture 100 outlined in 3GPP TR 23.786 Solution B1 (Annex B). The architecture of Figure 1 considers utilizing E-UTRAN (Evolved UMTS Terrestrial Radio Access Network), providing multicast/broadcast as specified in TS 36.440, since NG-RAN (Next Generation RAN) is composed of ng-eNB (providing E-UTRA user plane and control plane protocol) and gNB (providing NR user plane and control plane protocol). The architecture of Figure 1 proposes to adopt existing MBMS architecture principle and procedure in EPS (Evolved Packet System). Therefore, this is not a native 5G solution for broadcast but relies on continued use of an ng-eNB integrated with the 5GC (5G Core Network). Also, reusing the MBMS principles in 5G introduces high complexity and network functions (BMSC-UPF, BMSC-CPF, MB-UPF, MB-SMF, MCE) dedicated for broadcast, with complex procedures related to group management and MBMS session management. This may mean the flexibility requirements cannot be realized with this architecture.

Another known system architecture 200 discussed in 3GPP TR 23.786 Solution B2 (Annex B) is shown in Figure 2. This architecture considers that the RAT (Radio Access Technology) is E-UTRA; consequently, the RAN node is ng-eNB. Therefore, this is not a native 5G solution either. Additionally, the architecture of Figure 2 is not flexible (regarding the per packet broadcast area requirement) due to the following assumptions:

In the CN (Core Network), the G-SMF (Session Management Function) establishes an IP Multicast connection between the selected Group-UPF (User Plane Function) and (R)AN nodes involved in the group communication (GC) session. This means that for every new broadcast area (with different set of RAN nodes), a separate IP multicast session needs to be established. This causes significant delays when first broadcasting in new areas (which may be quite a frequent case when the data is coming from V2X-AS). Also, the management of IP multicast sessions is an additional complexity.

Group Session establishment procedure (including RAN, AMF, G-UPF, G-SMF, NEF, AF) is to be executed before transfer of group session data. A Groups Session is also tied to a set of UPF/RAN nodes, meaning that it has a fixed broadcast area (defined by the coverage of the corresponding RAN nodes). Such signaling per Group Session prevents per packet broadcast area flexibility.

For at least these reasons, the present disclosure provides alternative proposals for broadcasting in 5G systems.

Some embodiments will first be explained with respect to Figure 3. Figure 3 schematically shows some parts of a wireless telecommunications system 300, according to one example. The system 300 comprises UEs 302, 304, 306 and 308. UEs 302 and 304 are in communication with gNB 310, and UEs 306 and 308 are in communication with gNB 312. A UPF is shown at 316. gNB 310 and gNB 312 are part of Radio Access Network (RAN) 324. The UPF is in communication with gNBs 310 and 312. UPF 316 is also in communication with SMF 314 and AF 318. Communication between the UPF and the AF is over the N6 interface. Communication between the UPF 316 and the SMF 314 is over the N4 interface.

The disclosure relates to an in-band programmable broadcast service for 5G, provided by the UPF 316 to the AF 318 over the N6 interface. By “in-band” is meant that control information is sent on the same channel or band as data, such as voice or video data (e.g., in the payload of IP packets). The in- band programmability feature means that the AF 318 may send a U-plane (user plane) packet to the UPF 316 for broadcasting without any prior C-plane (control plane) broadcast session establishment procedure. This is because the N6 interface is extended to accept packets that are self-contained combinations of broadcast area information and the broadcast data itself. In-band programmability also ensures that the broadcast area may be arbitrated (i.e. changed) from packet to packet, again without any control plane procedure between the AF 318 and the UPF 316. As opposed to the architectures shown in Figures 1 and 2, the proposed service is fully provided within the Release-15 5G network functions, without having to create/integrate additional ones (such as from the MBMS architecture). Also, the proposed service uses 5G NR gNB instead of E-UTRA/ng-eNB in the RAN.

The disclosure can be further understood from the procedure schematically shown in Figure 3. At SI, the AF 318 sends a combination of broadcast data and a broadcast area definition via N6 bi plane connection to the UPF 316. The broadcast data is transparent to the 5G system. By “transparent” is meant that the 5G system does not need to understand the information that is broadcast to the UEs, the 5G system just needs to understand where/how to broadcast it. In examples the data is sent to UEs within the broadcast area without interpretation or modification by the system. In some examples, the broadcast area definition comprises a list of Cell IDs. In some examples the broadcast area definition enumerates or lists the RAN cells where the data should be broadcasted. In some examples the broadcast data comprises vehicle related information such as V2X CAM (cooperative awareness message). In other, non-V2X specific cases the broadcast data may even comprise voice and/or video data.

At S2 (further described below as S2a and S2b), the UPF 316 needs to translate the Cell IDs to a gNB transport layer IP address usable in the U-plane (N3 interface) to access those gNBs that are hosting one or more of the cells in the broadcast area (e.g. gNBs 310 and 312).

Thus, as shown at S2a, a service is provided by the SMF 314 to the UPF 316 over N4. The service may be considered an address resolution service. Thus, in this example, the service may be considered a “Cell ID to gNB N3 address resolution service”.

At S2b, the UPF 316 accesses the address resolution service of SMF 314 over N4. This enables the UPF 316 to map the broadcast area Cell IDs to gNB IP addresses (e.g. addresses of gNBs 310 and/or 312) on the N3 interface.

At S3, for each gNB that hosts one or more of the broadcast area Cell IDs, the UPF 316 sends the broadcast data and those Cell IDs that belong to the addressed gNB. That is, each involved gNB receives the broadcast data and one or more of its own Cell IDs.

At S4, each gNB broadcasts the received broadcast data in its designated cells over Uu. For example, gNB 310 broadcasts the received data to UEs 302 and 304, and/or gNB 312 broadcasts the received data to UEs 306 and 308.

Some implementation details will now be explained in more detail.

In some examples, the AF 318 comprises a MEC platform service (providing flexible broadcast/unicast service to MEC applications), or a MEC application implementing such broadcast/unicast functionality directly. In some examples, the AF 318 comprises functionality for sending or relaying messages between vehicles. More particularly the AF 318 may comprise V2X-AS (V2X application server) functionality, which relays V2X messages between vehicles in a V2N connectivity service. The V2X-AS may decide for example, for each V2X message, whether broadcast is more efficient than unicast, and if so, which are the cells where the broadcast needs to take place. In some examples the V2X-AS may learn the ID of the cell currently serving each vehicle from the vehicle itself. For example, the vehicle may embed this information in V2X messages sent to the V2X-AS to be relayed to other vehicles, or in separate messages to be consumed by the V2X-AS itself. The collection of Cell IDs by the V2X-AS is in-line with the 3GPP TS 23.285 clause 4.3.3.

Figure 4 shows a procedure which may be carried out before the AF 318 may start to use the in-band programmable broadcast service to perform a broadcast service authentication. Thus, the procedure of Figure 4 may be considered a pre -cursor to the procedure (SI to S4) shown in Figure 3. In examples the method of Figure 4 is executed between the AF and the 5G system before the AF becomes eligible to submit broadcast packets to the UPF. In examples the relationship between the AF and the 5G system, established in Fig 4, is valid for many broadcast packets (not just for one packet).

Figure 4 shows UPF 316 and AF 318. A Network Exposure Function (NEF) 320 is communicatively located between UPF 316 and AF 318. The UPF 316 comprises or is in communication with an authentication (AUTFi) database 322.

At SI the AF 318 contacts the NEF 320 and sends a Broadcast Authentication Request with the N6 IP address of the AF 318 (which is used to transfer IP packets on the N6 interface - could be a public Internet IP address for example). Optionally the AF 318 sends the NEF 320 a geo-area. Optionally the AF 318 sends the NEF 320 a time. The geo-area may be a geographical area defined with a shape such as a circle, oval or polygon; or a map region name (e.g., a city); or any other way of defining a geographical area. The time may be a time interval (e.g., from 2019-01-01 9:00 CET to 2019- 06-3023:59 CET); or a periodic time interval definition (e.g., “weekdays between 9:00-17:00”), or any other time definition. The geo-area and time may be used by the system (NEF and UPF) to limit the authorized broadcast to the specified geo-area and/or time.

It is further to be noted that the geographical area (geo-area) is not necessarily the broadcast area. For example, the geo-area may define a largest possible broadcast area, though it may be expected that the actual broadcast area of a given broadcast packet will be much smaller. For example, a geo area may be a whole city (e.g., Budapest), meaning that the AF becomes authorized to send packets to be broadcasted anywhere within Budapest (i.e., for a given packet, listing a few cell IDs that physically reside in Budapest). Flowever, packets will not necessarily be broadcast throughout Budapest. In this example packets with a broadcast area outside of Budapest will be discarded by the UPF.

At S2, the NEF 320 evaluates the request and, if it is acceptable, generates an authentication (AUTFI) token. In some examples the AUTFI token is an unpredictable unique identifier (e.g., random number). The grant (i.e. AUTFI token) is sent from the NEF 320 to the AF 318. According to examples the communication between the NEF 320 and the AF 318 is secure. Therefore, the AUTFI token remains a secret between the NEF 320 and the AF 318. In some examples the NEF 320 may also transfer an UPF UDP port number to the AF 318, if the UPF 316 accepts U-plane broadcast packets over UDP on a given port on N6. At S3 the NEF 320 also transfers the AUTH token to the UPF(s) 316 which serve the geo-area specified in the initial request (or all UPFs if there was no geo-area). The NEF 320 also transfers the AF N6 IP address and the time (if time was provided by the AF) to the UPF(s) 316.

At S4 the UPF(s) 316 store the AUTH token, AF N6 IP address and (optionally) time and (optionally) geo-area in the AUTH database 322. As mentioned, the AUTH database may be implemented within the UPF 316 or may be a database provided by a database/storage server accessible by the UPF.

After authorization is completed, the AF 318 may start sending U-plane packets to the UPF 316 without any additional C-plane (e.g. NEF) procedure. The end-to-end U-plane packet transfer is shown in Error! Reference source not found., showing the relevant logical content of a packet at every interface (N6, N3, and Uu). Shown in Figure 5 are AF 318; UPF 316; RAN 324 (e.g. comprising gNBs 310 and 312) and UE 302 (of course in examples there may be more UEs).

On the N6 interface

The AF 318 may be required to provide the AUTH token to the UPF 316 with every piece of broadcast data, so that the UPF 316 may check (in real-time) whether the broadcast is authorized (and facilitate the broadcasting of the data only if the authorization is established). More details of this authorization are given later in the discussion of Error! Reference source not found.. In order to protect the AUTH token on the N6 interface, the AF 318 and the UPF 316 (in some examples with the mediation of the NEF 320) may establish a security context to cypher/authenticate the packet header and content. For example the security context may be a one-time -pad (OTP) security context (e.g., using AES- 128 counter mode).

The packet contains the Broadcast Area Definition, which may be a list of Cell IDs.

The packet contains the Broadcast data, which is transparent to the network and will be ultimately delivered to the UEs located in the Cell IDs provided in the broadcast area definition.

The UPF removes the AUTH token and checks its validity. Unauthorized packets will be discarded (details provided later with Error! Reference source not found.). Other packets are forwarded on the N3 interface.

On the N3 interface

The UPF 316 obtains the list of gNBs (and their respective N3 IP address) that own one or more of the Cell IDs listed in the Broadcast Area Definition. The implementation discussion of this procedure is provided further below with respect to Figure 7 and Figure 8. The UPF 316 forwards, to each gNB, a Limited Broadcast Area Definition. By “limited” is meant that it includes only those Cell IDs that are owned by the gNB(s) in the list.

The UPF 316 forwards the broadcast data without any change to the gNB(s) in the list.

On the Uu interface

Each gNB broadcasts the broadcast data in the cells listed in the Limited Broadcast Area Definition to UE(s) (e.g. UE 302) over the Uu interface.

Figure 6 shows the protocol stack on the N3 and N6 interfaces. One implementation option uses GTP-U on the N6 interface, leveraging the GTP-U Extension Header capability to include the AUTH token and the list of Cell IDs in the GTP-U header, and provide the broadcast data in the packet payload. The UDP port at which the UPF accepts broadcast packets may be configured in the AF 318 by the NEF 320 as part of the broadcast service authorization procedure (Error! Reference source not found.). On the N3 interface, the same GTP-U protocol stack may be used, with GTP (GPRS Tunnelling Protocol) Extension Header to convey the Cell IDs. On the N3 interface, the broadcast packets may be differentiated from the regular PDU session packets by using a different UDP port, or based on the GTP-U Extension Header presence, or based on other packet marking mechanism.

A functionality of the disclosed UPF 316 is ability to map the Cell IDs received from the AF 318 to gNB N3 IP addresses (e.g. IP address of gNB 310 or 312). This is enabled by a new service provided by the SMF 314 to the UPF 316 via N4. The service is described with respect to Figure 7. The SMF 314 implements a Cell-IP database 315. The Cell-IP database 315 stores key-value pairs, the keys being Cell IDs and the values being gNB N3 IP addresses. The UPF 316 may query the SMF 314 to resolve a Cell ID to an IP address. A “database” is one example of how the Cell ID and base station address pairs may be stored. It will thus be understood that the Cell ID and base station address pairs (gNB N3 IP addresses) may be considered more generally to be stored in an entity.

Thus, as shown in Figure 7, at SI the UPF 316 sends an address resolution service request (for Cell ID) to SMF 314.

At S2 the SMF 314 sends a Cell ID query to the Cell-IP database 315.

At S3 the Cell-IP database 315 responds to the SMF 314 with the IP address.

At S4 the SMF 314 sends the address resolution response (i.e. the IP address) to the UPF 316.

An alternative implementation instead of the N4 procedure of Figure 7 is to share the Cell-IP database between the SMF and the UPF, so that the UPF may directly query the database instead of going through an N4 procedure. In some examples this implementation is better from performance point of view. The implementation is shown in Error! Reference source not found, which shows shared Cell-IP database 315 between UPF 316 and SMF 314.

As shown at SI, the UPF 316 can send a Cell ID query directly to Cell-IP database 315.

As shown at S2, the UPF can receive the IP address response directly from the Cell-IP database

315.

Regardless of whether the implementation alternative of Error! Reference source not found, or Error! Reference source not found, is used, the SMF 314 has to collect Cell ID and gNB N3 IP address pairs. In one implementation, this information may be pre-configured in the SMF 314 or may be obtained from an inventory database. In one alternative implementation the SMF 314 learns such pairs without any pre-configuration. In some examples the SMF 314 performs such learning by collecting the information from the UE initiated PDU Session Establishment procedure (the standard procedure is described in 3GPP TS 23.502). Within this procedure, the SMF 314 obtains, as per Release- 15 standard, the User Location Information and the AN (Access Network) Tunnel Information during every protocol data unit (PDU) Session Establishment procedure. The User Location Information is equivalent with the Cell ID; the AN Tunnel Information is equivalent to the gNB N3 IP address. By storing these two pieces of information linked in a Cell-IP database 315, the SMF learns about every cell of a given gNB through which a PDU session is established.

Referring to Figure 9, the relevant messages of the Release- 15 standard PDU Session Establishment procedure are shown that convey the User Location Information or the AN Tunnel Information to the SMF. At the end of the procedure (i.e. afterS 15), in a new part of the procedure shown as S16, the SMF 314 writes the Cell ID - gNB N3 IP address pair into the Cell-IP database 315. In a further implementation, a timestamp may also be added to the data record in the Cell-IP database 315 indicating the latest time when a PDU session has been established in the given cell. This could be used to age out Cell ID - gNB N3 IP associations that have not been used for a predetermined (e.g. long) time. Via this automated information collection the SMF will naturally obtain information from under its supervised area, i.e., about those gNBs that it is serving via the attached UPFs. This automatically focuses the information collection within a large 5G deployment, which could not be handled by pre -configuration.

An alternative implementation to that shown in Error! Reference source not found, is that in SI 6a of the Release- 15 PDU Session Establishment procedure (not shown in Error! Reference source not found, but part of 3GPP TS 23.502 figure 4.3.2.2.1-1), when the SMF 314 provides the AN Tunnel Info to the UPF 316 in N4 Session Modification Request, the SMF 314 also provides the User Location Information to the UPF 316. Therefore, the UPF 316 receives both Cell ID and gNB N3 IP address. The UPF 316 then manages its own Cell-IP database without having to query the SMF 314 via N4. Figure 10 is a flow-chart depicting operation of UPF 316 during broadcast of a packet.

At SI, the UPF 316 receives a U-plane packet on the N6 interface. The U-plane packet contains an AF N6 IP address, an AUTH token, one or more cell IDs, and broadcast data.

At S2 the UPF 316 queries the authorization record stored by the NEF 320 for the AUTH token received in the packet.

As shown at S3, if there is no record, it means that the AF 318 has not obtained authorization from the NEF 320 and the packet is dropped. If the record shows authorization for a different AF N6 IP address, or there has been an authorized time specification which does not include the current time (i.e., the packet has arrived outside of the authorized time intervals), the packet is also dropped.

Thus, as shown at the decision block of S4, if the record does not exist, or the record does not match, or the current time is not within the record’s time, then the flow proceeds to S5 and the packet is dropped.

Otherwise, as shown at S6, the UPF 316 obtains the gNB N3 IP addresses that own the Cell IDs listed by the packet by querying the SMF 314. The flowchart of Figure 10 shows an implementation where the SMF 314 provides the Cell ID to gNB N3 address resolution service via N4 (see Error! Reference source not found.). Other implementations may also be supported with small adaptation in the flow (e.g., querying the Cell-IP database directly instead of via the SMF).

The UPF 316 has to unify the list of the gNB N3 IPs because broadcast may have been requested by the AF 318 in multiple cells that belong to the same gNB, therefore a simple query for gNB N3 IPs based on Cell IDs may return the same gNB N3 IP multiple times. Therefore as shown at S7 the UPF 316 creates a unique list of gNB N3 IP addresses.

As shown at S8 the UPF replicates the broadcast data for each gNB that is involved in the broadcast (each gNB owns one or more of the listed cells). The UPF 316 creates a separate N3 packet for each gNB, destined to the N3 IP address of the gNB. The gNB also creates a narrowed list of Cell IDs for each gNB, containing only those Cell IDs that are owned by the gNB (corresponding to the Limited Broadcast Area Definition in Error! Reference source not found.).

The packets are then sent to the gNBs via N3, as shown at S9.

A possible wireless communication device will now be described in more detail with reference to Figure 11 showing a schematic, partially sectioned view of a communication device 1100 (which may be equivalent to, for example, the UEs 302, 304, 306 and 308 shown in Figure 3). Such a communication device is often referred to as user equipment (UE) or terminal. An appropriate mobile communication device may be provided by any device capable of sending and receiving radio signals. Non-limiting examples comprise a mobile station (MS) or mobile device such as a mobile phone or what is known as a ’smart phone’, a computer provided with a wireless interface card or other wireless interface facility (e.g., USB dongle), personal data assistant (PDA) or a tablet provided with wireless communication capabilities, or any combinations of these or the like. A mobile communication device may provide, for example, communication of data for carrying communications such as voice, electronic mail (email), text message, multimedia and so on. Users may thus be offered and provided numerous services via their communication devices. Non-limiting examples of these services comprise two-way or multi-way calls, data communication or multimedia services or simply an access to a data communications network system, such as the Internet. Users may also be provided broadcast or multicast data. Non limiting examples of the content comprise downloads, television and radio programs, videos, advertisements, various alerts and other information.

A wireless communication device may be for example a mobile device, that is, a device not fixed to a particular location, or it may be a stationary device. The wireless device may need human interaction for communication, or may not need human interaction for communication. In the present teachings the terms UE or “user” are used to refer to any type of wireless communication device.

The wireless device 1100 may receive signals over an air or radio interface 1107 via appropriate apparatus for receiving and may transmit signals via appropriate apparatus for transmitting radio signals. In Figure 11 transceiver apparatus is designated schematically by block 1106. The transceiver apparatus 1106 may be provided for example by means of a radio part and associated antenna arrangement. The antenna arrangement may be arranged internally or externally to the wireless device.

A wireless device is typically provided with at least one data processing entity 1101, at least one memory 1102 and other possible components 1103 for use in software and hardware aided execution of tasks it is designed to perform, including control of access to and communications with access systems and other communication devices. The data processing, storage and other relevant control apparatus can be provided on an appropriate circuit board and/or in chipsets. This feature is denoted by reference 1104. The user may control the operation of the wireless device by means of a suitable user interface such as key pad 1105, voice commands, touch sensitive screen or pad, combinations thereof or the like. A display 1108, a speaker and a microphone can be also provided. Furthermore, a wireless communication device may comprise appropriate connectors (either wired or wireless) to other devices and/or for connecting external accessories, for example hands-free equipment, thereto.

Figure 12 shows an example of a control apparatus 1200 for a communication system, for example to be coupled to and/or for controlling a station of an access system, such as a RAN node, e.g. a base station, gNB, a central unit of a cloud architecture or a node of a core network such as an MME or S-GW, a scheduling entity such as a spectrum management entity, or a server or host. The control apparatus 1200 may comprise a function such as an AF, UPF, SMF etc.). The control apparatus 1200 may be integrated with or external to a node or module of a core network or RAN. In some embodiments, base stations comprise a separate control apparatus unit or module. In other embodiments, the control apparatus can be another network element such as a radio network controller or a spectrum controller. In some embodiments, each base station may have such a control apparatus as well as a control apparatus being provided in a radio network controller. The control apparatus 1200 can be arranged to provide control on communications in the service area of the system. The control apparatus 1200 comprises at least one memory 1201, at least one data processing unit 1202, 1203 and an input/output interface 1204. Via the interface the control apparatus can be coupled to a receiver and a transmitter of the base station. The receiver and/or the transmitter may be implemented as a radio front end or a remote radio head. For example, the control apparatus 1200 or processor 1201 can be configured to execute an appropriate software code to provide the control functions.

Figure 13 is a flow chart showing a method according to an example. The method of Figure 13 is viewed from the perspective of an apparatus. For example, the apparatus may be a UPF.

At SI, the method comprises receiving data to be broadcast and a broadcast area definition in a same user-plane packet.

At S2, the method comprises using the broadcast area definition to determine one or more base stations to send the broadcast data to.

At S3, the method comprises sending the broadcast data to the one or more base stations.

Figure 14 is a flow chart showing a method according to an example. The method of Figure 14 is viewed from the perspective of an apparatus. For example, the apparatus may be an AF.

At S 1 , the method comprises sending data to be broadcast and a broadcast area definition in a same user-plane packet to a user plane function.

Figure 15 is a flow chart showing a method according to an example. The method of Figure 15 is viewed from the perspective of an apparatus. For example, the apparatus may be an SMF.

At S 1 the method comprises storing one or more cell-identifier and base station address pairs in a database.

At S2 the method comprises sending a base station address to a user plane function in response to a query from the user plane function, the query comprising a cell-identifier.

It will be understood that some of the procedures illustrated may be performed sequentially, in parallel or in an order other than which is described. Some of the procedures described may also be repeated. Also, it should be appreciated that not all of the techniques described are required to be performed, that additional techniques may be added, and that some of the illustrated techniques may be substituted with other techniques.

In general, the various embodiments may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects of the disclosure may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although the disclosure is not limited thereto. While various aspects of the disclosure may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

As used in this application, the term “circuitry” may refer to one or more or all of the following: (a) hardware -only circuit implementations (such as implementations in only analog and/or digital circuitry) and(b) combinations of hardware circuits and software, such as (as applicable): (i) a combination of analog and/or digital hardware circuit(s) with software/firmware and (ii) any portions of hardware processor(s) with 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) hardware circuit(s) and or processor(s), such as a microprocessor s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation. 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 also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and/or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

The embodiments of this disclosure may be implemented by computer software executable by a data processor of the mobile device, such as in the processor entity, or by hardware, or by a combination of software and hardware. Computer software or program, also called program product, including software routines, applets and/or macros, may be stored in any apparatus-readable data storage medium and they comprise program instructions to perform particular tasks. A computer program product may comprise one or more computer-executable components which, when the program is run, are configured to carry out embodiments. The one or more computer-executable components may be at least one software code or portions of it.

Further in this regard it should be noted that any blocks of the logic flow as in the Figures may represent program steps, or interconnected logic circuits, blocks and functions, or a combination of program steps and logic circuits, blocks and functions. The software may be stored on such physical media as memory chips, or memory blocks implemented within the processor, magnetic media such as hard disk or floppy disks, and optical media such as for example DVD and the data variants thereof, CD. The physical media is a non-transitory media.

The memory 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. The data processors may be of any type suitable to the local technical environment, and may comprise one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASIC), FPGA, gate level circuits and processors based on multi core processor architecture, as non-limiting examples.

Embodiments of the disclosure may be practiced in various components such as integrated circuit modules. The design of integrated circuits is by and large a highly automated process. Complex and powerful software tools are available for converting a logic level design into a semiconductor circuit design ready to be etched and formed on a semiconductor substrate.

The foregoing description has provided by way of non-limiting examples a full and informative description of the exemplary embodiment of this disclosure. However, various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings and the appended claims. However, all such and similar modifications of the teachings of this disclosure will still fall within the scope of this disclosure as defined in the appended claims. Indeed there is a further embodiment comprising a combination of one or more embodiments with any of the other embodiments previously discussed.

Claims

1. An apparatus comprising means for performing: receiving data to be broadcast and a broadcast area definition in a same user-plane packet; using the broadcast area definition to determine one or more base stations to send the broadcast data to; and sending the broadcast data to the one or more base stations.

2. An apparatus according to claim 1, wherein the means are further configured to perform receiving the data to be broadcast and the broadcast area definition from an application function on an N6 user-plane connection.

3. An apparatus according to claim 1 or claim 2, wherein the means are further configured to perform using the broadcast area definition to determine one or more base stations to forward the broadcast data to by obtaining base station address information.

4. An apparatus according to claim 3, wherein the means are further configured to obtain the base station address information from an entity which stores cell identifier and base station address pairs.

5. An apparatus according to claim 4, wherein the means are further configured to directly query the entity for the base station address information.

6. An apparatus according to claim 4, wherein the means are further configured to query a session management function which stores the entity for the base station address information.

7. An apparatus according to any of claims 1 to 6, wherein the means are further configured to perform receiving and storing an authentication token at the apparatus.

8. An apparatus according to claim 7, wherein the authentication token defines one or more of the following parameters: a geographical area which the broadcast data may potentially be broadcast to; a time period.

9. An apparatus according to claim 7 or claim 8, wherein the means are further configured to perform checking the authentication token before sending the broadcast data to the one or more base stations.

10. An apparatus according to any of claims 1 to 9, wherein the apparatus comprises a user plane function.

11. An apparatus according to any of claims 1 to 10, wherein the means comprises at least one processor; and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

12. An apparatus comprising means for performing: sending data to be broadcast and a broadcast area definition in a same user-plane packet to a user plane function.

13. An apparatus according to claim 12, wherein the means are further configured to perform sending the data to be broadcast and the broadcast area definition to a user-plane function on an N6 user-plane connection.

14. An apparatus according to claim 12 or claim 13, wherein the broadcast area definition comprises a list of cell identifiers.

15. An apparatus according to any of claims 12 to 14, wherein the means are further configured to perform obtaining an authentication token.

16. An apparatus according to claim 15, wherein the authentication token defines one or more of the following parameters: a geographical area which the broadcast data may potentially be broadcast to; a time period.

17. An apparatus according to claim 15 or claim 16, wherein the means are further configured to perform sending the authentication token to the user plane function in the same user plane packet as the data to be broadcast and the broadcast area definition.

18. An apparatus according to any of claims 12 to 17, wherein the apparatus comprises an application function.

19. An apparatus according to any of claims 12 to 18, wherein the means comprises at least one processor; and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

20. An apparatus comprising means for performing: storing one or more cell-identifier and base station address pairs in a database; and sending a base station address to a user plane function in response to a query from the user plane function, the query comprising a cell-identifier.

21. An apparatus according to claim 20, the base station address comprising an internet protocol address.

22. An apparatus according to claim 20 or claim 21, wherein the apparatus is pre -configured with the cell-identifier and base station address pairs.

23. An apparatus according to any of claims 20 to 22, wherein the means are further configured to perform learning the cell-identifier and base station address pairs by collecting the information from a user equipment initiated protocol data unit session establishment procedure.

24. An apparatus according to claim 23, wherein the means are further configured to perform obtaining timestamp information during the protocol data unit session establishment procedure, and subsequently using the timestamp information to cancel cell-identifier base station address pairs which have not been used for a predetermined amount of time.

25. An apparatus according to any of claims 20 to 24, wherein the apparatus comprises a session management function.

26. An apparatus according to any of claims 20 to 25, wherein the means comprises at least one processor; and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

27. A method comprising: receiving data to be broadcast and a broadcast area definition in a same user-plane packet; using the broadcast area definition to determine one or more base stations to send the broadcast data to; and sending the broadcast data to the one or more base stations.

28. A method comprising: sending data to be broadcast and a broadcast area definition in a same user-plane packet to a user plane function.

29. A method comprising: storing one or more cell-identifier and base station address pairs in a database; and sending a base station address to a user plane function in response to a query from the user plane function, the query comprising a cell-identifier.

30. A computer program comprising instructions for causing an apparatus to perform at least the following: receiving data to be broadcast and a broadcast area definition in a same user-plane packet; using the broadcast area definition to determine one or more base stations to send the broadcast data to; and sending the broadcast data to the one or more base stations.

31. A computer program comprising instructions for causing an apparatus to perform at least the following: sending data to be broadcast and a broadcast area definition in a same user-plane packet to a user plane function.

32. A computer program comprising instructions for causing an apparatus to perform at least the following: storing one or more cell-identifier and base station address pairs in a database; and sending a base station address to a user plane function in response to a query from the user plane function, the query comprising a cell-identifier.