WO2020020430A1

WO2020020430A1 - Management of distributed and centralised self organising network functions

Info

Publication number: WO2020020430A1
Application number: PCT/EP2018/069921
Authority: WO
Inventors: Liam Fallon; Sven VAN DER MEER
Original assignee: Telefonaktiebolaget LM Ericsson AB
Current assignee: Telefonaktiebolaget LM Ericsson AB
Priority date: 2018-07-23
Filing date: 2018-07-23
Publication date: 2020-01-30
Anticipated expiration: 2021-01-23

Abstract

Management of distributed and centralised Self Organising Network functions A method for coordinating management of distributed and centralised implementations of SON functions operable to interact with a network is disclosed. An implementation of a SON function is associated with a function context comprising data items used by the implementation to perform its function, and centralised implementations of a SON function use a first coordination mechanism to share their function contexts. The method comprises maintaining a mapping between: individual context data items comprised within the contexts of implementations of SON functions, and distributed implementations of SON functions that include the context data items in their function context (510). The method further comprises propagating changes made to the mapped context data items between the first coordination mechanism of the centralised implementations of SON functions and individual distributed implementations of SON functions in accordance with the mapping (530).

Description

Management of distributed and centralised Self Organising Network functions

Technical Field

The present disclosure relates to a method for coordinating management of distributed and centralised implementations of Self Organising Network (SON) functions, which implementations are operable to interact with a network. The present disclosure also relates to a management coordinator and to a computer program product configured, when run on a computer, to carry out a method for coordinating management of distributed and centralised implementations of SON functions.

Background

Self Organising Network (SON) is a concept for the management of communication networks according to which one or more instances of network functions (SON functions) independently perform network management tasks. A SON function instance collects data relevant to its management task, including for example measurements of network parameters or Key Performance Indicators (KPIs), calculates updated values of one or more configuration parameters for the network, and causes the calculated values to be deployed on the network. The set of data items used by a SON function instance, including both collected and configured data items, is referred to as the context of the SON function instance. The Third Generation Partnership Project (3GPP) identifies three categories of SON functions, including Self-Configuration, Self-Optimisation and Self-Healing. Examples of SON functions include Automatic Neighbour Relation, Mobility Load Balancing, Mobility Robustness Optimisation, Energy Saving, Cell Outage Compensation, etc. A deployment of SON function instances may be centralised, distributed or hybrid, as discussed in further detail below.

Figure 1 illustrates a Centralised SON (C-SON) deployment 100 comprising n centralised implementations 102 of n SON functions. Each C-SON function implementation operates on its domain (neighbour relation, energy saving etc.). The illustrated deployment is coordinated, as each C-SON function implementation shares its context with the other C-SON functions via a Context Coordination mechanism 104. Different C-SON functions may monitor and/or seek to configure the same network parameters for different purposes, giving rise to the possibility of conflict between different C-SON function instances. The Context Coordination mechanism 104 enables such conflicts to be detected, mitigated, and in some cases completely eliminated. WO 2018/024348 discloses a distributed network management method which may be used to realise the Context Coordination mechanism 104.

The Context Coordination Mechanism 104 interacts with the network 108 via a Context Mediation function 106. The Context Mediation function 106 provides interfaces to the network 108 for the reading and setting of data. Some such interfaces may be standard interfaces such as Integration Reference Points (IRPs) specified in 3GPP TS 32.150 version 15.0.0, Management Information Bases (MIBs) specified in the Internet Engineering Task Force (IETF) Request for Comments (RFC) 1213, or Management and Orchestration for Network Functions Virtualisation (MANO) interfaces specified by the European Telecommunications Standards Institute (ETSI) in ETSI GS NFV-MAN 001 v1 .1.1 . Proprietary interfaces for controlling distributed implementations of SON functions may also be supported by the Context Mediation function 106. The Context Mediation function 104 provides mediation between the centralised deployment of SON functions and the network 108. The distributed network management method of WO 2018/024348 is an example of a method which may be used to realise the Context Mediation function 104.

Figure 2 illustrates a hybrid SON deployment 200 comprising coordinated C-SON implementations and uncoordinated Distributed SON (D-SON) implementations. The deployment 200 comprises C-SON implementations 202, Context Coordination mechanism 204, Context Mediation 206 and a network 208. The deployment 200 also comprises a plurality of D-SON implementations 210. D-SON functions are typically implemented in and across nodes in the network. The D-SON functionality in different network nodes communicates directly to optimise some aspect of the network such as handovers, energy saving, or relationships between nodes. D-SON functions are often proprietary and“black box”. The network features the functions act on and the controls for the D-SON function are known and may be standardised. However, the internal algorithms and manner of operation of the D-SON functions are not generally known by or published to other D-SON functions. The distributed implementations 210 of Functions 1 , 2 and n in the deployment 200 are not therefore aware of each other.

Figure 3 illustrates a real world example 300 of the hybrid SON deployment of Figure 2. The deployment 300 comprises three SON functions: COC (Cell Outage Compensation), ANR (Automatic Neighbour Relation), and ES (Energy Saving). A centralised implementation 302a, 302b, 302c of each function is running in the centralised deployment, with coordination between the centralised implementations provided by the Context Coordination mechanism 304 and interfaces to the network 308 provided by the Context Mediation function 306. A number of distributed implementations 310 of these functions are also running within the network 308. It can be observed that Vendor 1 has deployed ES and COC D-SON function implementations 310a, 310c, Vendor 2 has deployed ANR and COC D-SON function implementations and Vendor 3 has deployed a COC D-SON function implementation 310c.

The Vendor 1 , Vendor 2 and Vendor 3 COC D-SON functions 310c are unaware of each other. Some vendors provide coordination across the different D-SON functions they provide, meaning the Vendor 1 ES and COC D-SON functions 310a and 310c in Figure 3 may coordinate across each other to detect, mitigate, and eliminate conflicts. However, the potential for conflict between the centralised and distributed implementations of the same functions (such as C-SON ES 302a and D-SON ES 310a), and between distributed implementations of the same functions from different vendors (such as Vendor 1 , 2 and 3 COC 310c) still exists.

Figure 4 illustrates one manner in which ad-hoc coordination can be integrated into a centralised SON deployment to enable coordination with distributed SON function implementations in a hybrid situation. As illustrated in Figure 4, an adaptor 412 is written for each C-SON function 402 towards each D-SON implementation 410. As Functions 1 and 2 only have one distributed implementation each running in the network 408, only a single adaptor 412a, 412b is written for each centralised implementation of these functions. However, there are three distributed implementations 410c of Function n running in the network 408. Three separate adaptors 412c1 , 412c2 and 412c3 are therefore written for the centralised implementation of Function n, one adaptor for each distributed implementation of the function. This approach is feasible if there are only a few C-SON and D-SON function implementations. As the number of C-SON and D-SON function implementations increases, the number of adapters required increases exponentially. Another drawback of this approach is that it only works for each separate SON function. It cannot detect, mitigate, or eliminate conflicts across SON function domains, for example between COC and ANR.

Summary It is an aim of the present invention to provide a method, apparatus and computer readable medium which at least partially address one or more of the challenges discussed above.

According to a first aspect of the present disclosure, there is provided a method for coordinating management of distributed and centralised implementations of SON functions operable to interact with a network, wherein an implementation of a SON function is associated with a function context comprising data items used by the implementation to perform its function, and wherein centralised implementations of a SON function use a first coordination mechanism to share their function contexts. The method comprises maintaining a mapping between: individual context data items comprised within the contexts of implementations of SON functions, and distributed implementations of SON functions that include the context data items in their function context. The method further comprises propagating changes made to the mapped context data items between the first coordination mechanism of the centralised implementations of SON functions and individual distributed implementations of SON functions in accordance with the mapping.

According to examples of the present disclosure, interaction between a centralised or distributed SON function and the network may comprise monitoring and updating, by the SON function, of one or more network parameters. Interaction between a centralised or distributed SON function and the network may be direct or may be indirect. Indirect interaction may involve an intermediary, such as for example the monitoring and updating of network parameters by invoking interfaces provided by a mediation function.

According to examples of the present disclosure, maintaining a mapping may comprise, on instantiation of a centralised or distributed implementation of a SON function, obtaining metadata describing data items comprised within the function context of the function implementation and creating an entry in the mapping for context data items described by the metadata for which an entry in the mapping does not already exist. Maintaining a mapping may further comprise, on instantiation of a distributed implementation of a SON function, associating a reference to the distributed implementation with mapping entries corresponding to context data items in the context of the distributed implementation. According to examples of the present disclosure, maintaining a mapping may further comprise, on instantiation of a distributed implementation of a SON function, obtaining metadata describing mechanisms for monitoring and setting values for data items in the context of the distributed implementation, and generating an instance of a function mapper for the distributed implementation on the basis of the metadata, wherein the function mapper instance is operable to monitor at least one parameter relating to the distributed implementation and to issue instructions to the distributed implementation.

According to examples of the present disclosure, the function mapper instance may be operable to issue instructions to the distributed implementation via a Context Mediation function that is configured to provide interfaces to the network for reading and setting of data by SON functions.

According to examples of the present disclosure, generating an instance of a function mapper for a distributed implementation of a SON function on the basis of obtained metadata may comprise retrieving a function mapper template corresponding to an interface provided by the Context Mediation function which will be used by the distributed implementation of a SON function, and configuring the retrieved template using the obtained metadata to generate a function mapper instance for the distributed implementation of a SON function.

According to examples of the present disclosure, associating a reference to the distributed implementation with mapping entries corresponding to context data items in the context of the distributed implementation may comprise writing a reference to the function mapper of the distributed implementation against mapping entries for context data items in the context of the distributed implementation.

According to examples of the present disclosure, propagating changes made to the mapped context data items may comprise establishing that a change has been made to a mapped context data item and, for changes made by a centralised implementation of a SON function, propagating the changed value of the context data item to distributed implementations of SON functions mapped to that context data item, and, for changes made by a distributed implementation of a SON function, propagating the changed value of the context data item to the first coordination mechanism of the centralised implementations of SON functions and to distributed implementations of SON functions mapped to that context data item. According to examples of the present disclosure, for changes made by a distributed implementation of a SON function, the change may be propagated to all mapped distributed implementations excluding the distributed implementation that caused the change.

According to examples of the present disclosure, establishing that a change has been made to a mapped context data item may comprise at least one of detecting a change to the context item in the first coordination mechanism of the centralised implementations of SON functions, detecting a change to the context item via monitoring or polling of the network, and/or receiving a notification of a change to the context item.

According to examples of the present disclosure, propagating changes made to the mapped context data items may comprise detecting a change to a context data item in the first coordination mechanism of the centralised implementations of SON functions, sending the changed value of the context data item to function mappers for which a reference is written against the entry for the changed context data item in the mapping; and propagating, by function mappers receiving the changed value, the changed value of the context data item to distributed implementations of a SON function corresponding to the function mappers.

According to examples of the present disclosure, propagating changes made to the mapped context data items may comprise establishing that a change has been made to a mapped context data item by a distributed implementation of a SON function, writing the changed value of the context data item to the first coordination mechanism of the centralised implementations of SON functions, sending the changed value of the context data item to function mappers for which a reference is written against the entry for the changed context data item in the mapping, and propagating, by function mappers receiving the changed value, the changed value of the context data item to distributed implementations of a SON function corresponding to the function mappers.

According to examples of the present disclosure, propagating, by function mappers, the changed value of the context data item to distributed implementations of a SON function corresponding to the function mappers may comprise, in a function mapper, invoking at least one of a command or Application Programming Interface (API) call to propagate the changed value to its corresponding distributed implementation of a SON function. According to examples of the present disclosure, invoking, by a function mapper, at least one of a command or API call to propagate the changed value to its corresponding distributed implementation of a SON function may comprise invoking the command or API on a Context Mediation function configured to provide interfaces to the network for reading and setting of data by SON functions.

According to examples of the present disclosure, the method may be performed by a management coordination function for centralised and distributed SON functions.

According to examples of the present disclosure, the management coordination function for centralised and distributed SON functions may be a Virtualised Network Function (VNF) deployed on a Network Functions Virtualization Infrastructure (NFVI). According to another aspect of the present disclosure, there is provided a method for providing context mediation to distributed and centralised implementations of SON functions operable to interact with a network, wherein an implementation of a SON function is associated with a function context comprising data items used by the implementation to perform its function. The method comprises receiving a notification from a distributed implementation of a SON function of a change made by the distributed implementation to a context data item in its context, and sending a notification to a management coordination function for centralised and distributed SON functions, the notification including the changed value of the context data item. According to examples of the present disclosure, sending a notification may comprise sending the notification to a function mapper within the management coordination function that corresponds to the distributed implementation of a SON function that made the change to the context data item. According to another aspect of the present disclosure, there is provided a computer program comprising instructions which, when executed on at least one processor, cause the at least one processor to carry out a method according to any one of the preceding aspects or examples of the present disclosure. According to another aspect of the present disclosure, there is provided a carrier containing a computer program according to the preceding aspect of the present disclosure, wherein the carrier comprises one of an electronic signal, optical signal, radio signal or computer readable storage medium.

According to another aspect of the present disclosure, there is provided a computer program product comprising non transitory computer readable media having stored thereon a computer program according to a preceding aspect of the present disclosure.

According to another aspect of the present disclosure, there is provided a Management Coordinatorfor coordinating management of distributed and centralised implementations of SON functions operable to interact with a network, wherein an implementation of a SON function is associated with a function context comprising data items used by the implementation to perform its function, and wherein centralised implementations of a SON function use a first coordination mechanism to share their function contexts. The Management Coordinator comprises a processor and a memory, the memory containing instructions executable by the processor such that the Management Coordinator is operable to maintain a mapping between: individual context data items comprised within the contexts of implementations of SON functions, and distributed implementations of SON functions that include the context data items in theirfunction context, and propagate changes made to the mapped context data items between the first coordination mechanism of the centralised implementations of SON functions and individual distributed implementations of SON functions in accordance with the mapping.

According to examples of the present disclosure, the Management Coordinator may be further operable to maintain a mapping by, on instantiation of a centralised or distributed implementation of a SON function, obtaining metadata describing data items comprised within the function context of the function implementation, and creating an entry in the mapping for context data items described by the metadata for which an entry in the mapping does not already exist, and, on instantiation of a distributed implementation of a SON function, associating a reference to the distributed implementation with mapping entries corresponding to context data items in the context of the distributed implementation.

According to examples of the present disclosure, the Management Coordinator may be further operable to maintain a mapping by, on instantiation of a distributed implementation of a SON function, obtaining metadata describing mechanisms for monitoring and setting values for data items in the context of the distributed implementation, and generating an instance of a function mapper for the distributed implementation on the basis of the metadata, wherein the function mapper instance is operable to monitor at least one parameter relating to the distributed implementation and to issue instructions to the distributed implementation.

According to examples of the present disclosure, the Management Coordinator may be further operable to propagate changes made to the mapped context data items by establishing that a change has been made to a mapped context data item, and, for changes made by a centralised implementation of a SON function, propagating the changed value of the context data item to distributed implementations of SON functions mapped to that context data item, and, for changes made by a distributed implementation of a SON function, propagating the changed value of the context data item to the first coordination mechanism of the centralised implementations of SON functions and to distributed implementations of SON functions mapped to that context data item.

According to examples of the present disclosure, the Management Coordinator may be further operable to implement a management coordination function for centralised and distributed SON functions.

According to examples of the present disclosure, the management coordination function for centralised and distributed SON functions may be a VNF deployed on a NFVI.

According to examples of the present disclosure, the Management Coordinator may be further operable to carry out a method according to any one of the preceding aspects or examples of the present disclosure.

According to another aspect of the present disclosure, there is provided a Management Coordinatorfor coordinating management of distributed and centralised implementations of SON functions operable to interact with a network, wherein an implementation of a SON function is associated with a function context comprising data items used by the implementation to perform its function, and wherein centralised implementations of a SON function use a first coordination mechanism to share their function contexts. The management coordinator comprises a Context Mapper operable to maintain a mapping between: individual context data items comprised within the contexts of implementations of SON functions, and distributed implementations of SON functions that include the context data items in their function context. The Management Coordinator further comprises a Context Publisher and Function Coordinator operable to propagate changes made to the mapped context data items between the first coordination mechanism of the centralised implementations of SON functions and individual distributed implementations of SON functions in accordance with the mapping.

According to examples of the present disclosure, the Context Mapper may be operable to, on instantiation of a centralised or distributed implementation of a SON function, obtain metadata describing data items comprised within the function context of the function implementation, and create an entry in the mapping for context data items described by the metadata for which an entry in the mapping does not already exist; and, on instantiation of a distributed implementation of a SON function, associate a reference to the distributed implementation with mapping entries corresponding to context data items in the context of the distributed implementation.

According to examples of the present disclosure, the Function Coordinator may be operable to, on instantiation of a distributed implementation of a SON function, obtain metadata describing mechanisms for monitoring and setting values for data items in the context of the distributed implementation, and generate and store an instance of a function mapper for the distributed implementation on the basis of the metadata, wherein the function mapper instance is operable to monitor at least one parameter relating to the distributed implementation and to issue instructions to the distributed implementation.

According to examples of the present disclosure, the function mapper instance may be operable to issue instructions to the distributed implementation via a Context Mediation function configured to provide interfaces to the network for reading and setting of data by SON functions.

According to examples of the present disclosure, the Function Coordinator may be operable to generate an instance of a function mapper for a distributed implementation of a SON function on the basis of obtained metadata by retrieving a function mapper template corresponding to an interface provided by the Context Mediation function which will be used by the distributed implementation of a SON function, and configuring the retrieved template using the obtained metadata to generate a function mapper instance for the distributed implementation of a SON function. According to examples of the present disclosure, the Context Mapper may be operable to associate a reference to the distributed implementation with mapping entries corresponding to context data items in the context of the distributed implementation by writing a reference to the function mapper of the distributed implementation against mapping entries for context data items in the context of the distributed implementation.

According to examples of the present disclosure, the Context Publisher may be operable to detect a change to a context data item in the first coordination mechanism of the centralised implementations of SON functions and send the changed value of the context data item to the Context Mapper. The Context Mapper may be operable to send the changed value of the context data item to function mappers for which a reference is written against the entry for the changed context data item in the mapping maintained by the Context Mapper. The function mappers stored by the Function Coordinator may be operable to propagate a received changed value of a context data item to their corresponding distributed implementations of SON functions.

According to examples of the present disclosure, the function mappers stored by the Function Coordinator may be operable to establish that a change has been made to a mapped context data item by their corresponding distributed implementation of a SON function and send the changed value of the context data item to the Context Mapper. The Context Mapper may be operable to send the changed value of the context data item to the Context Publisher and to function mappers for which a reference is written against the entry for the changed context data item in the mapping maintained by the Context Mapper. The Context Publisher may be operable to write the changed value of the context data item to the first coordination mechanism of the centralised implementations of SON functions. The function mappers stored by the Function Coordinator may be further operable to propagate a received changed value of a context data item to their corresponding distributed implementations of SON functions.

According to examples of the present disclosure, the function mappers stored by the Function Coordinator may be operable to invoke at least one of a command or API call to propagate a changed value of a context data item to their corresponding distributed implementations of SON functions.

According to examples of the present disclosure, the function mappers stored by the Function Coordinator may be operable to invoke the command or API on a Context Mediation function configured to provide interfaces to the network for reading and setting of data by SON functions.

According to examples of the present disclosure, the Management Coordinator may implement a management coordination function for centralised and distributed SON functions.

Brief Description of the Drawings

For a better understanding of the present invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example, to the following drawings in which:

Figure 1 is a block diagram illustrating a Centralised SON (C-SON) deployment;

Figure 2 is a block diagram illustrating a hybrid SON deployment;

Figure 3 is a block diagram illustrating a real world example of the hybrid SON deployment of Figure 2;

Figure 4 is a block diagram illustrating ad-hoc coordination for the hybrid SON deployment of Figure 2;

Figure 5 is a flow chart illustrating process steps in a method for coordinating management of centralised and distributed implementations of SON functions;

Figures 6a, 6b and 6c are flow charts illustrating process steps in another example of a method for coordinating management of centralised and distributed implementations of SON functions;

Figure 7 is a flow chart illustrating process steps in a method for providing context mediation to distributed and centralised implementations of SON functions; Figure 8 is a block diagram illustrating a hybrid SON deployment with management coordinator;

Figure 9 is a block diagram illustrating a real world example of the hybrid SON deployment of Figure 8;

Figure 10 is a block diagram illustrating functional units in a management coordinator;

Figure 1 1 is a block diagram illustrating functional units in another example of management coordinator;

Figure 12 is a block diagram illustrating run-time information flow in the management coordinator of Figure 1 1 ;

Figure 13 is a block diagram illustrating a real world example of the management coordinator of Figure 1 1 ; and

Figure 14 is a block diagram illustrating functional units in another example of management coordinator.

Detailed Description

Aspects of the present disclosure provide a method enabling coordination between distributed and centralised implementations of SON functions. A mapping is maintained between individual context data items comprised within the contexts of implementations of SON functions, and those distributed implementations of SON functions that include the context data items in their function context. Changes made to the mapped context data items are then propagated between a first coordination mechanism of centralised implementations of SON functions and individual distributed implementations of SON functions in accordance with the mapping. In this manner, context data item changes made by a C-SON deployment may be made visible to D-SON function implementations, and changes made by individual D-SON function implementations may be made visible to C-SON as well as to other D-SON function implementations. This coordination is enabled without need for dedicated adaptors for each distributed implementation, and may easily adapt to the instantiation of new SON function implementations during run- time. According to examples of the disclosure, the method may be metadata driven, with metadata describing data items comprised within the function context of a function implementation being obtained on instantiation of the implementation, and appropriate entries being made in the mapping to associate newly instantiated distributed function implementations with mapping entries corresponding to the data context items in their function contexts.

Figure 5 illustrates a first example of a method 500 for coordinating management of distributed and centralised implementations of SON functions operable to interact with a network. According to examples of the method, an implementation of a SON function may be associated with a function context comprising data items used by the implementation to perform its function, and centralised implementations of a SON function may use a first coordination mechanism to share their function contexts. The distributed network management method of WO 2018/024348 may in some examples be used to realise the first coordination mechanism. The method 500 may be carried out by a management coordinator and comprises, in a first step 510, maintaining a mapping between: individual context data items comprised within the contexts of implementations of SON functions, and distributed implementations of SON functions that include the context data items in their function context. The method further comprises, in a step 530, propagating changes made to the mapped context data items between the first coordination mechanism of the centralised implementations of SON functions and individual distributed implementations of SON functions in accordance with the mapping.

Figures 6a, 6b and 6c illustrate another example of a method 600 for coordinating management of distributed and centralised implementations of SON functions operable to interact with a network. The method 600 of Figures 6a, 6b and 6c illustrates one way in which the steps of the method 500 of Figure 5 may be subdivided and supplemented to achieve the above discussed and additional functionality. As for the method 500 of Figure 5, according to examples of the method, an implementation of a SON function may be associated with a function context comprising data items used by the implementation to perform its function, and centralised implementations of a SON function may use a first coordination mechanism to share their function contexts. The first coordination mechanism may in some examples be realised using a management method such as that disclosed in WO 2018/024348. The method 600 may be carried out by a management coordinator. Referring to Figure 6a, the step 510 in method 500 of maintaining a mapping may involve updating the mapping each time a new centralised or distributed implementation of a SON function is instantiated. An initial mapping may be generated when a new deployment is placed in the field, with the substantially simultaneous instantiation of multiple centralised and/or distributed implementations, and the mapping may be updated during operation as individual implementations are instantiated, updated or removed from service. As illustrated in Figure 6a, steps to maintain the mapping may be triggered by the instantiation of a centralised or distributed implementation of a SON function at step 602. In the case of a centralised implementation, the method 600 may comprise obtaining metadata describing data items comprised within the function context of the function implementation in step 612, and creating an entry in the mapping for context data items described by the metadata for which an entry in the mapping does not already exist. Context data items may include all network parameters and/or Key Performance Indicators (KPIs) which are either measured or adjusted by the SON function in order to execute its purpose. On instantiation of a subsequent implementation of a function which already has one or more implementations running, entries may already exist in the mapping for all context data items in the context of the new implementation. However, if any context data item in the context of the new implementation is not already present in the mapping, an entry may be created for it at step 614.

On instantiation of a distributed implementation of a SON function, the method comprises obtaining metadata describing data items comprised within the function context of the new implementation at step 616 and creating an entry in the mapping for context data items described by the metadata for which an entry in the mapping does not already exist in step 618. These steps are substantially the same as steps 612 and 614 carried out for a new centralised implementation. In the case of a new distributed implementation, the method further comprises associating a reference to the distributed implementation with mapping entries corresponding to context data items in the context of the distributed implementation at step 620. This may comprise writing a reference to a function mapper for the distributed implementation against appropriate context data item mapping entries, as discussed in further detail below. The step 620 ensures that the mapping reflects the relationships between individual context data items and the distributed implementations of SON functions to which they are relevant. Thus a mapping may contain entries for n different context data items, only some of which will be of relevance to any one individual distributed SON function implementation. The mapping ensures that the propagation of changes to SON functions, discussed in detail below, is carried out between only those distributed implementations of SON functions for which the changed context data items are relevant (that is they appear in the implementation’s function context either as a data item for monitoring or a data item which the function may act upon to change its value).

For a newly instantiated distributed function implementation, the method further comprises the step 622 of obtaining metadata describing mechanisms for monitoring and setting values for data items in the context of the newly instantiated distributed SON function implementation. On the basis of this metadata, the method further comprises the step 624 of generating an instance of a function mapper for the distributed implementation, the function mapper operable to monitor at least one parameter relating to the distributed implementation and to issue instructions to the distributed implantation. As discussed in further detail below, the instructions may be issued via a Context Mediation function. A Context Mediation function may be configured to provide interfaces to the network for reading and setting of data by SON functions, as discussed above.

The process of generating an instance of a function mapper for a distributed implementation of a SON function is illustrated in further detail in Figure 6b. Referring to figure 6b, in a first step 624a, generating a function mapper comprises retrieving a function mapper template corresponding to an interface provided by a Context Mediation function which will be used by the distributed implementation of a SON function. In step 624b, generating a function mapper further comprises configuring the retrieved template using the obtained metadata to generate a function mapper instance for the newly instantiated distributed implantation of a SON function.

Referring again to Figure 6a, steps 612 to 624 illustrate one way in which a mapping as described above may be maintained between individual context data items and distributed implementations of SON functions for which those context data items are relevant. A context data item may be considered to be relevant to a SON function implementation if the context data item appears in the function context of the implementation.

Referring now to Figure 6c, the method 600 further comprises establishing that a change has been made to a mapped data context item in step 626. This step may be accomplished in different ways depending upon whether the change was made by a centralised or distributed implementation of a SON function. In the case of a change made by a centralised implementation of a SON function, the change may be detected in a first coordination mechanism of centralise implementations of SON functions at step 626a. In the case of a change made by a distributed implementation of a SON function, the change may be detected via monitoring or polling of the network at step 626b. In further examples, a change made by a distributed implementation of a SON function may be notified, for example by a Context Mediation function, which notification may be received at step 626c.

Following establishment of a change to a mapped context data item, that change is propagated according to the maintained mapping. In the case of a change made by a centralised implementation of a SON function, the changed value is propagated to distributed implementations of SON functions mapped to that context data item in step 632. This may comprise sending the changed value of the context data item to function mappers for which a reference is written against the entry for the changed context data item in the mapping in step 636. Function mappers receiving the changed value may then propagate the changed value of the context data item to the distributed implementations of a SON function to which they are corresponding in step 638.

In the case of a change made by a distributed implementation of a SON function, the changed value is propagated to the first coordination mechanism of the centralised implementations of SON functions and to distributed implementations of SON functions mapped to that context data item in step 634. In this manner, coordination is effected not just between the centralised and distributed deployments but also between individual distributed implementations of SON functions, which may otherwise be completely unaware of each other. Step 634 may comprise writing the changed value of the context data item to the first coordination mechanism of the centralised implementations of SON functions in step 640. Sep 634 may further comprise sending the changed value of the context data item to function mappers for which a reference is written against the entry for the changed context data item in the mapping in step 642 and propagating, by function mappers receiving the changed value, the changed value of the context data item to distributed implementations of a SON function corresponding to the function mappers in step 644.

It will be appreciated that the steps involved in maintaining the mapping between context data items and distributed function implementations, and in establishing and propagating a change to a mapped context value, may be carried out substantially independently. Thus, the mapping may be updated each time a new implementation is instantiated, and changes may be propagated between the centralised first coordination mechanism and individual distributed implementations of SON functions as they are established. Examples of the method 600 allow for full coordination across SON function domains and between centralised and distributed deployments of SON functions, detecting and mitigating the effects of potential conflicts between function implementations which may be operating in different domains and/or be provided by different vendors. The method 600 is metadata driven and hence flexible, with context and function mappings being defined at run time and updated as new implementations are deployed.

It will also be appreciated that it may in some circumstances be desirable to run certain SON function implementations independently of the management coordination described in the present disclosure. If such implementations are not isolated from a part of the network in which examples of the above described methods are running, then conflict between these uncoordinated SON function implementations and those implementations coordinated by the above described methods may occur. It may therefore be desirable to isolate any uncoordinated SON function implementations in a separate zone of the network.

As discussed above, in some examples a management coordinator performing the method 500 or 600 may be notified of a change made to a mapped context data item by a Context Mediation function. Figure 7 illustrates a method 700 for providing context mediation to distributed and centralised implementations of SON functions operable to interact with a network, wherein an implementation of a SON function is associated with a function context comprising data items used by the implementation to perform its function. The method 700 comprises, in a first step 710, receiving a notification from a distributed implementation of a SON function of a change made by the distributed implementation to a context data item in its context. The method further comprises, in step 720, sending a notification to a management coordination function for centralised and distributed SON functions, the notification including the changed value of the context data item. As illustrated in Figure 7, sending a notification may comprise sending the notification to a function mapper within the management coordination function that corresponds to the distributed implementation of a SON function that made the change to the context data item. Figure 8 illustrates a hybrid SON deployment 800 in which a management coordinator 820, which may carry out examples of the method 500 and/or 600, is operating. The hybrid deployment 800 comprises C-SON function implementations 802 and a first context coordination mechanism 804 used by the C-SON function implementations 802 to share their function contexts. The deployment 800 further comprises a network 808 and a context mediation function 806 which provides interfaces to the network 808 for the reading and setting of data. The deployment 800 also comprises a plurality of D- SON function implementations 810. The D-SON functions may be implemented in and across nodes in the network, with the D-SON functionality in different network nodes communicating directly to carry out the SON function. Each D-SON function implementation coordinates its own data, and there may be some minimal coordination between D-SON function implementations supplied by the same vendor. Alternatively, the distributed implementations 810 of Functions 1 , 2 and n in the deployment 800 may be completely unaware of each other. The management coordinator 820 performs SON conflict detection and mitigation according to examples of the method 500, 600 illustrated above. The coordination performed by the management coordinator 820 allows the various centralised and distributed SON function implementations 802, 810 to read and operate on SON data seamlessly. By reading and writing changes to context data items directly from/to the first coordination mechanism 804 of the centralised SON function implementations 802, the management coordinator 820 acts as, and appears to the centralised SON function implementations to be, another C-SON function implementation. As discussed above, the management coordinator 820 may use both standard and proprietary interfaces provided by the context mediation function 806 to monitor and control SON data in each D-SON function that uses and sets SON data.

Figure 9 illustrates a real world example 900 of the hybrid SON deployment of Figure 8. It will be appreciated that the example hybrid deployment 900 of Figure 9 resembles that of Figure 3, with the difference that a management coordinator 920 carrying out examples of the method 500 and/or 600 is operating. Metadata 922 for the Energy Saving (ES), Automatic Neighbour Relation (ANR) and Cell Outage Compensation (COC) SON functions provided by Vendors 1 , 2 and 3 is obtained by the management coordinator 920 and used to maintain a mapping between context data items and distributed SON function implementations. The obtained metadata may also be used in some examples to generate function mappers for each of the distributed function implementations. The coordination performed by the management coordinator 920 ensures that the C-SON ES, ANR, and COC functions 902 interact and cooperate with, and do not interfere with, the Vendor 1 , Vendor 2, and Vendor 3 D-SON implementations of those functions 910. The coordination of the management coordinator is performed using the first context coordination mechanism 904 of the centralised function implementations 902 and the network context mediation function 906 as discussed above.

Figure 10 is a block diagram illustrating functional modules in an example of a management coordinator 1020, which may perform examples of the methods 500 and/or 600 as discussed above, for example according to computer readable instructions received from a computer program. The management coordinators 820, 920 discussed above may comprise the functional modules of the management coordinator 1020. It will be understood that the modules of management coordinator 1020 are functional modules and may be realised in any appropriate combination of hardware and/or software. The term module may have conventional meaning in the field of electronics, electrical devices and/or electronic devices and may include, for example, electrical and/or electronic circuitry, devices, processors, processing circuitry, memories, logic, solid state and/or discrete devices, computer programs or instructions for carrying out respective tasks, procedures, computations, outputs, and/or displaying functions, and so on, as such as those that are described in the present disclosure. The modules may be integrated to any degree.

Referring to Figure 10, the management coordinator 1020 comprises a context mapper 1030 operable to maintain a mapping between: individual context data items comprised within the contexts of implementations of SON functions, and distributed implementations of SON functions that include the context data items in their function context. The management coordinator further comprises a context publisher 1040 and function coordinator 1050 operable to propagate changes made to the mapped context data items between the first coordination mechanism of the centralised implementations of SON functions and individual distributed implementations of SON functions in accordance with the mapping. The management coordinator further comprises interfaces 1060.

Figure 1 1 is a block diagram illustrating functional units in another example of management coordinator 1 120. Figure 1 1 illustrates in greater detail how the functional units of the management coordinator 1020 of Figure 10 may operate. According to examples of the present disclosure, the context mapper 1 130 controls the coordination of context data items that are visible to C-SON to D-SON functions. The context publisher 1 140 publishes those context data items and their reads and writes into the first context coordination mechanism 1 104 of the centralised SON functions. As discussed above, the first context coordination mechanism 1 104 may be realised using a method as disclosed in WO 2018/024348. The function coordinator 1 150 manages coordination of SON data for each D-SON function that exists in a hybrid deployment (or for each D- SON function that is being coordinated by the management coordinator 1 120).

The context mapper 1 130 manages the mapping between context data items and D- SON functions. The context data items that should be mapped and the D-SON functions they should be mapped to are described in metadata 1 122 and are initialised in the context mapper 1 130 when the metadata is loaded.

The function coordinator 1 150 contains a collection of D-SON function mappers 1 152. A function mapper template is developed for each type of interface (standard and proprietary) supplied by the context mediation function 1 106. A template function mapper reads KPIs and counters and issues commands or API calls in whatever vernacular the context mediation function 1 106 uses for the particular interface for which the template is developed. An appropriate function mapper template may then be configured with metadata for a specific D-SON function implementation when the implementation is instantiated, so generating a function mapper specific to the particular implementation. In one example, a Vendor 1 function mapper template may be developed that applies to all D-SON function implementations supplied by Vendor 1 . For a COC function implementation, this mapper template would be initiated with metadata that specifies a certain set of KPIs and counters that must be monitored and a certain set of commands and API calls that must be used to control the Vendor 1 COC D-SON function. For ANR, another instance of the same function mapper would be initiated with different metadata that specifies the KPIs, counters, commands and API calls for the Vendor 1 ANR D-SON function. Similar templates may be developed for other Vendors.

The context publisher 1 140 propagates C-SON changes (that is changes carried out by C-SON function implementations and written into the first context coordination mechanism 1 104) to the context data items being managed by the context mapper 1 130. The context publisher also propagates changes to context data items managed by the context mapper 1 130 to the first context coordination mechanism 1 104. Figure 12 is a block diagram illustrating run-time information flow in the management coordinator 1 120 of Figure 1 1 , referred to in Figure 12 as management coordinator 1220. In the example situation illustrated in Figure 12, n context data items are being co- ordinated between C-SON and three D-SON Function implementations. Changes to Context Item 1 are propagated between C-SON and the three D-SON function implementations using an entry in the context mapper 1230 with three references, one reference to each of the three D-SON functions mappers corresponding to the three D- SON function implementations. Each D-SON function mapper maps changes from and to its D-SON function implementation. Changes to Context Item 2 are propagated between C-SON and two of the three D-SON function implementations using an entry in the context mapper 1230 with references to the relevant two function mappers. Changes to the remaining context items are propagated in a corresponding manner.

Figure 13 is a block diagram illustrating a real world example of the management coordinator of Figure 1 1 . In the illustrated example, it is assumed that a single context data item exists for each SON function. It will be appreciated that in other examples, multiple context data items may exist for each SON function implementation and may be handled in accordance with examples of the methods 500 and./or 600.

An example distribution of the steps carried out according to examples of the methods 500 and/or 600 between the different functional modules of the management coordinator 1320 is described below.

Maintaining a mapping:

1 . Metadata for the three SON functions (COC, ANR, and ES) and the six D-SON function implementations (three for COC, two for ANR, and one for ES) is loaded into the management coordinator 1320.

2. The management coordinator 1320 reads the metadata for the SON shared data and creates an entry for each SON context data item in the context mapper 1330.

3. The management coordinator 1320 reads the metadata for each D-SON implementation of a SON function and creates a D-SON function mapper instance for each implementation in the function co-ordinator 1350.

4. The management coordinator 1320 records references to the function mapper instances in the context mapper 1330 in accordance with the context data items that are present in the function context of each D-SON function implementation. Thus, a reference to the function mapper for each of the COC D-SON function implementations is written next to the entry for the COC context data item. Similarly, a reference to the function mapper for each of the ANR D-SON function implementations is written next to the entry for the ANR context data item etc.

Propagating changes from C-SON to D-SON:

1 . The context publisher 1340 detects a change in a context data item in the first context coordination mechanism 1304 and sends the new value for the context data item to the context mapper 1330.

2. The context mapper 1330 propagates the change to each D-SON function mapper for which a reference is written next to the context data item whose value has changed.

3. Each D-SON function mapper invokes the appropriate commands and API calls on the context mediation function 1306 to propagate the change down to its D-SON function.

Propagating changes from D-SON function implementation to C-SON and rest of D-SON (notification example):

1 . A D-SON function implementation changes a value of a context data item and notifies the context mediation function 1306.

2. The context mediation function notifies the appropriate D-SON function mapper in the function coordinator 1350.

3. The function mapper notifies the context mapper 1330 of the change to the context data item value.

4. The context mapper 1330 uses the context publisher 1340 to change the value of the appropriate context data item in the first context coordination mechanism 1304 of the centralised SON function implementations (so propagating the change to C-SON).

5. The context mapper propagates the change to the other D-SON function mappers for which a reference is written in the context mapper 1330 against the changed context data item.

6. Those other D-SON function mappers invoke the appropriate commands and API calls on context mediation to propagate the change down to their D-SON function implementations. Propagating changes from D-SON function implementation to C-SON and rest of D-SON (monitoring example):

1 . A D-SON function implementation changes a value and notifies the context mediation function 1306.

2. The function mapper for the D-SON function implementation notices the change using KPI or counter monitoring or polling.

5. The D-SON context mapper propagates the change to the other D-SON function mappers for which a reference is written in the context mapper 1330 against the changed context data item.

6. Those other D-SON function mappers invoke the appropriate commands and API calls on context mediation to propagate the change down to their D-SON function implementations.

Figure 14 is a block diagram illustrating functional units in another example of management coordinator 1420. The management coordinator 1420 may implement the methods 500, 600 according to examples of the present disclosure, for example on receipt of suitable instructions from a computer program 1500. Referring to Figure 14, the management coordinator comprises a processor or processing circuitry 1470, a memory 1480 and interfaces 1460. The memory 1480 contains instructions, for example in the form of a computer program, executable by the processor 1470 such that the management coordinator is operative to conduct the steps of the method 500 and/or 600. The instructions may also include instructions for executing one or more telecommunications and/or data communications protocols. The instructions may be stored in the form of the computer program 1500. In some examples, the processor or processing circuitry 1470 may include one or more microprocessors or microcontrollers, as well as other digital hardware, which may include digital signal processors (DSPs), special-purpose digital logic, etc. The processor or processing circuitry 1470 may be implemented by any type of integrated circuit, such as an Application Specific Integrated Circuit (ASIC), Field Programmable Gate Array (FPGA) etc. The memory 1480 may include one or several types of memory suitable for the processor, such as read-only memory (ROM), random-access memory, cache memory, flash memory devices, optical storage devices, solid state disk, hard disk drive etc.

It will be appreciated that the management coordinators described above may in some examples be deployed in a cloud infrastructure. The functional modules of a management coordinator may be implemented as Virtualised Network Functions, and may be deployed on a Network Functions Virtualization Infrastructure. In further examples, the methods 500 and/or 600 may be implemented in alternative functional elements deployed on a cloud infrastructure.

As discussed above, examples of the methods 500 and 600, as implemented in any of the above discussed examples of management coordinator, are driven by the use of metadata. Metadata may be used to specify what context data items are shared between C-SON and D-SON functions and to specify how this data is monitored and set in each D-SON function. Metadata may be loaded, amended, and removed at run time to change the way mappings work during operation of the management coordinator.

The code block below shows an example structure of metadata which may be used according to examples of the present disclosure:

^"SONCDMMetadata^" : {

^"ContextMappings^": [

{

^"ContextObjectID^" : ^"<Context Co-Ordination Object/^', "FunctionMapperlD^": ^"<D-S0N Function Mapper ID>^"

],

^"FunctonCoordi nation^": [

{

"FunctionMapperlD^": ^"<D-S0N Function Mapper ID>^",

^"ContextObjectID^": ^'/Context Co-Ordination Object/^',

^"MapperType^" : ^'/Mapper that handles mappings for this type of mediation/^',

^"Mediator ID^": ^'/Context Mediation Mediator Reference/^', "Monitor ingDi recti ves^": ^'/Monitoring directives understood by a mapper of

This Mapper Type/^',

^"Sett ingDi recti ves^": ^'/Setting directives understood by a mapper of this

Mapper Type> ]

The ContextMappings section maps a ContextObjectID that is known by and controlled by the first context coordination mechanism of the centralised SON function implementations to a function mapper of the management coordinator, the function mapper having a given ID. There may be multiple instances of the same ContextObjectID, one for each D-SON function to which it is being mapped. However, each FunctionMapperlD should be unique. An entry appears in the FunctionCoordination section of the metadata for each function mapper. The entry is keyed by the FunctionMapperlD. The FunctionCoordination entry also contains a ContextObjectID reference because the function mapper should have a reference to the context item it is acting on. The MediatorlD reference is a reference to the context mediation module being used for receiving and sending to the network.

The MapperType reference tells the management coordinator which type of mapper to load for this mapping. Mappers are written as plugins for the management coordinator and handle the mappings of arbitrary context items to context mediation. For example, there may be a standard 3GPP mapper for handling 3GPP mediation of context items to 3GPP IRP interfaces. There may also be individual mappers for specific vendors; for example one mapper for Vendor 1 proprietary mediation and a separate mapper for Vendor 2 proprietary mediation etc. The mapper type for a particular type of mediation takes the ContextObjectID reference and the MediatorlD reference and handles the mapping to and from the mediation system for the context item.

The mapper monitors a D-SON function by interpreting and applying the MonitoringDirectives directives supplied to it. Likewise it controls and sets values in a D-SON function by interpreting and applying the SettingDirectives directives supplied to it.

The following example shows the structure of the metadata for four D-SON functions:

"SONCDMMetadata" : {

"ContextMapp i ngs" : [

{

"ContextObject I D" : "ContextCOCObject",

"Funct i onMapper I D" : "Vendor 1 _C0C"

} , {

ContextOb ject I D^" : ^"ContextCOCOb ject^",

Funct i onMapper ID^" : ^"Vendor2_C0C^"

} ,

{

ContextOb ject I D^" : ^"ContextCOCOb ject^",

Funct i onMapper ID^" : ^"Vendor3_C0C^"

} ,

{

ContextOb ject I D^" : ^"ContextANROb ject^",

Funct i onMapper ID^" : ^"Vendor 1_ANR^"

} ,

{

ContextOb ject I D^" : ^"ContextANROb ject^",

Funct i onMapper ID^" : ^"Vendor2_ANR^"

} ,

{

ContextObjectID^" : ^"ContextESObject^",

Funct i onMapper ID^" : ^"Vendor 1_ES^"

} ,

{

ContextOb ject I D^" : ^"ContextMLBOb ject^",

Funct i onMapper ID^": ^"3GPP_MLB^" ]

FunctonCoordi nation^": [

{

^"Funct i onMapper ID^" : ^"Vendor 1_C0C^",

^"ContextO OCOb ject^",

^"MapperTy etaryMapper^",

^"Med i ator

etaryMed i ator^",

^"Monitor ingDI recti ve^": ^"ContextCOCOb ject. Cel 1123. outageCount = VendorlPropr i etaryMed i ator. Cel 1123. outages^",

^"Sett ingDI recti ve^": ^"if (ContextCOCOb ject. Cel 1123. outageCount > 4)

{VendorlPropr i etaryMed i ator. Cel 1123. d i sab I e () } ^"

} ,

{

^"Funct i onMapper ID^" : ^"Vendor2_C0C^",

^"ContextO OCOb ject^",

^"MapperTy etaryMapper^",

^"Med i ator

etaryMed i ator^",

^"Monitor ingDI recti ve^": ^"ContextCOCOb ject. Cel 1456. outageCount = Vendor2Propr i etaryMed i ator. Cel I456. shutdowns +

Vendor2Propr i etaryMed i ator. Cel I456. sleeps^",

^"Sett ingDI recti ve^": ^"if (ContextCOCObject. Cel 1456. outageCount >

4)

{Vendor2Propr i etaryMed i ator. Cel 1456. shutdown ()} } ,

{

^"Funct i onMapper ID^" : ^"Vendor3_C0C^",

^"ContextObjectID^": ^"ContextCOCObject^",

^"MapperType^": ^"Vendor3Propr i etaryMapper^",

^"Med i ator I D^" : ^"Vendor3Propr i etaryMed i ator^",

"MonitoringDIrective^": ^"ContextCOCObject. Cel 1789. outageCount = Vendor3Propr i etaryMed i ator. getOutageCount () ^",

^"Sett ingDI recti ve^": ^"if (ContextCOCObject. Cel 1789. outageCount > 4)

{Vendor3Propr i etaryMed i ator. stop (¥^"Ce 11789¥^") } ^"

} ,

{

^"Funct i onMapper ID^" : ^"Vendor 1_ANR^",

^"ContextO ontextANRObject^",

^"MapperTy l Propr i etaryMapper^",

^"Med i ator l Propr i etaryMed i ator^",

"Monitori

: ^"for (nei ghbourRe I at ion in

Vendorl Propr i etaryMed i ator. ne i ghbourRe I at i onL i st)

{ContextANRObject. addNe i ghbourRe I at i on (ne i ghbourRe I at i on) } ^",

^"Sett ingD I recti ve^": ^"for (nei ghbourRe I at ion in

ContextANRObject. getRe I at i onL i st) {

if

(Vendorl Propr i etaryMed i ator. getRe I at i on (ne i ghbourRe I at i on)

. getStrength < 2)

{Vendor 1 Propr i etaryMed i ator . de I eteRe I at i on (ne i ghbourRe I at i on) } } ^"

} ,

{

^"Funct i onMapper ID^" : ^"Vendor2_ANR^",

^"ContextObjectID^": ^"ContextANRObject^",

^"MapperType^": ^"Vendorl Propr i etaryMapper^",

^"Med i ator I D^" : ^"Vendor2Propr i etaryMed i ator^",

"MonitoringDIrective^": ^"for (nei ghbourRe I at ion in

Vendor2Propr i etaryMed i ator. getRe I at i ons)

{ContextANRObject. addNe i ghbourRe I at i on (ne i ghbourRe I at i on) }

"Sett ingD I recti ve^": ^"for (nei ghbourRe I at ion in

ContextANRObject. getRe I at i onL i st)

{Vendor2Propr i etaryMed i ator. de I eteLowStrengthRe I at i ons (2) }

} ,

{

"Funct i onMapper ID^": ^"Vendor2_ANR^",

^"ContextO NRObject^",

^"MapperTy etaryMapper^",

^"Med i ator

etaryMed i ator^", ^"MonitoringDIrective^": ^"for (neighbourRelation in Vendor2Propr i etaryMed i ator. getRe I at i ons)

{ContextANROb ject. addNe i ghbourRe I at i on (ne i ghbourRe I at i on) } ^",

^"Sett ingD I recti ve^": ^"for (neighbourRelation in

ContextANROb ject. getRe I at i onL i st)

{Vendor2Propr i etaryMed i ator. de I eteLowStrengthRe I at i ons (2) } ^"

} ,

{

^"Funct i onMapper ID^" : ^"Vendor 1_ES^",

^"ContextO ESObject^",

^"MapperTy i etaryMapper^",

^"Med i ator i etaryMed i ator^",

^"Monitori

(baseStation in

Vendorl Propr i etaryMed i ator. getBaseStat i ons)

{ContextESObject. getBaseStat i on (baseStat i on. getName () )

. setPowerUsage (baseStat i on. getPowerUsage () ) } ^",

^"Sett ingDI recti ve^": ^"for (baseStation in

ContextESObject. getBaseStat i ons)

{VendorlPropr i etaryMed i ator. shutdown (baseStat i on. getName () ) } ^"

} ,

{

^"Funct i onMapper I D^" : ^"3GPP_MLB^",

^"ContextO textMLBObject^",

^"MapperTy er^",

^"Med i ator ator ^",

^"Monitori

^"m I b. setAI I (3GPPMediator. getMLBData () ^", "Sett ingDI recti ve^": ^"3GPPMediator. setAI I (ContextMLBObject) ^"

]

Aspects of the present disclosure thus provide methods and apparatus enabling coordination across boundaries between C-SON and D-SON functions. Examples of the present disclosure enable the propagation of changes made to context data items between centralised and distributed SON function deployments, rendering changes made in one of the centralised or distributed domains visible to relevant function implementations in the other domain. Examples of the present disclosure are driven by metadata, which may be used to describe the context data items for coordination as well as the way in which SON data should be transferred and read in distributed SON function implementations. When the metadata is loaded into a management coordinator, it initiates a coordination component for each D-SON domain and starts mapping of context items between C-SON context coordination the D-SON domains, enabling C- SON and D-SON to interact. Conflicts between C-SON and D-SON, and between individual D-SON function implementations can in this manner be identified and mitigated across C-SON and multiple D-SON functions, so allowing for seamless deployment and use of C-SON and D-SON functions in a hybrid arrangement, as well as seamless deployment of D-SON functions from different vendors in the same network. The methods and apparatus of the present disclosure enable C-SON and D-SON coordination without the need for bespoke adaptors to mediate between each individual C-SON and D-SON function implementation. In addition, adaptation to changing deployments is possible, as metadata may be loaded at run time to enable coordination with newly instantiated SON function implementations, or to adapt to changes made to an existing function deployment. Thus, support for new D-SON functions or D-SON proprietary implementations can be deployed and spun up on the fly.

The methods of the present invention may be implemented in hardware, or as software modules running on one or more processors. The methods may also be carried out according to the instructions of a computer program, and the present invention also provides a computer readable medium having stored thereon a program for carrying out any of the methods described herein. A computer program embodying the invention may be stored on a computer-readable medium, or it could, for example, be in the form of a signal such as a downloadable data signal provided from an Internet website, or it could be in any other form.

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

Claims

1. A method for coordinating management of distributed and centralised

implementations of Self Organising Network, SON, functions operable to interact with a network, wherein an implementation of a SON function is associated with a function context comprising data items used by the implementation to perform its function, and wherein centralised implementations of a SON function use a first coordination mechanism to share their function contexts; the method comprising:

maintaining a mapping between: individual context data items comprised within the contexts of implementations of SON functions and distributed implementations of SON functions that include the context data items in their function context; and

propagating changes made to the mapped context data items between the first coordination mechanism of the centralised implementations of SON functions and individual distributed implementations of SON functions in accordance with the mapping.

2. A method as claimed in claim 1 , wherein maintaining a mapping comprises: on instantiation of a centralised or distributed implementation of a SON function: obtaining metadata describing data items comprised within the function context of the function implementation; and

creating an entry in the mapping for context data items described by the metadata for which an entry in the mapping does not already exist; and

on instantiation of a distributed implementation of a SON function:

associating a reference to the distributed implementation with mapping entries corresponding to context data items in the context of the distributed

implementation.

3. A method as claimed in claim 2, wherein maintaining a mapping further comprises:

on instantiation of a distributed implementation of a SON function:

obtaining metadata describing mechanisms for monitoring and setting values for data items in the context of the distributed implementation; and

generating an instance of a function mapper for the distributed implementation on the basis of the metadata, wherein the function mapper instance is operable to monitor at least one parameter relating to the distributed implementation and to issue instructions to the distributed implementation.

4. A method as claimed in claim 3, wherein the function mapper instance is operable to issue instructions to the distributed implementation via a Context Mediation function that is configured to provide interfaces to the network for reading and setting of data by SON functions.

5. A method as claimed in claim 4, wherein generating an instance of a function mapper for a distributed implementation of a SON function on the basis of obtained metadata comprises:

retrieving a function mapper template corresponding to an interface provided by the Context Mediation function which will be used by the distributed implementation of a SON function; and

configuring the retrieved template using the obtained metadata to generate a function mapper instance for the distributed implementation of a SON function.

6. A method as claimed in any one of claims 3 to 5, wherein associating a reference to the distributed implementation with mapping entries corresponding to context data items in the context of the distributed implementation comprises:

writing a reference to the function mapper of the distributed implementation against mapping entries for context data items in the context of the distributed implementation.

7. A method as claimed in any one of the preceding claims, wherein propagating changes made to the mapped context data items comprises:

establishing that a change has been made to a mapped context data item; and for changes made by a centralised implementation of a SON function:

propagating the changed value of the context data item to distributed implementations of SON functions mapped to that context data item; and

for changes made by a distributed implementation of a SON function:

propagating the changed value of the context data item to the first coordination mechanism of the centralised implementations of SON functions and to distributed implementations of SON functions mapped to that context data item.

8. A method as claimed in claim 7, wherein establishing that a change has been made to a mapped context data item comprises at least one of: detecting a change to the context item in the first coordination mechanism of the centralised implementations of SON functions;

detecting a change to the context item via monitoring or polling of the network; receiving a notification of a change to the context item.

9. A method as claimed in claim 6, or claim 7 or 8 when dependent on claim 6, wherein propagating changes made to the mapped context data items comprises: detecting a change to a context data item in the first coordination mechanism of the centralised implementations of SON functions;

sending the changed value of the context data item to function mappers for which a reference is written against the entry for the changed context data item in the mapping; and

propagating, by function mappers receiving the changed value, the changed value of the context data item to distributed implementations of a SON function corresponding to the function mappers.

10. A method as claimed in claim 6, or any one of claims 7 to 9 when dependent on claim 6, wherein propagating changes made to the mapped context data items comprises:

establishing that a change has been made to a mapped context data item by a distributed implementation of a SON function;

writing the changed value of the context data item to the first coordination mechanism of the centralised implementations of SON functions;

1 1 A method as claimed in claim 9 or 10 wherein propagating, by function mappers, the changed value of the context data item to distributed implementations of a SON function corresponding to the function mappers comprises:

in a function mapper: invoking at least one of a command or Application Programming Interface, API, call to propagate the changed value to its corresponding distributed

implementation of a SON function.

12. A method as claimed in claim 11 , wherein invoking, by a function mapper, at least one of a command or API call to propagate the changed value to its

corresponding distributed implementation of a SON function comprises invoking the command or API on a Context Mediation function configured to provide interfaces to the network for reading and setting of data by SON functions.

13. A method as claimed in any one of the preceding claims, wherein the method is performed by a management coordination function for centralised and distributed SON functions.

14. A method as claimed in claim 13, wherein the management coordination function for centralised and distributed SON functions is a Virtualised Network Function, VNF, deployed on a Network Functions Virtualization Infrastructure, NFVI.

15. A method for providing context mediation to distributed and centralised implementations of Self Organising Network, SON, functions operable to interact with a network, wherein an implementation of a SON function is associated with a function context comprising data items used by the implementation to perform its function, the method comprising:

receiving a notification from a distributed implementation of a SON function of a change made by the distributed implementation to a context data item in its context; and

sending a notification to a management coordination function for centralised and distributed SON functions, the notification including the changed value of the context data item.

16. A method as claimed in claim 15, wherein sending a notification comprises sending the notification to a function mapper within the management coordination function that corresponds to the distributed implementation of a SON function that made the change to the context data item.

17. A computer program comprising instructions which, when executed on at least one processor, cause the at least one processor to carry out a method according to any one of the preceding claims.

18. A carrier containing a computer program as claimed in claim 17, wherein the carrier comprises one of an electronic signal, optical signal, radio signal or computer readable storage medium.

19. A computer program product comprising non transitory computer readable media having stored thereon a computer program as claimed in claim 17.

20. A Management Coordinator for coordinating management of distributed and centralised implementations of Self Organising Network, SON, functions operable to interact with a network, wherein an implementation of a SON function is associated with a function context comprising data items used by the implementation to perform its function, and wherein centralised implementations of a SON function use a first coordination mechanism to share their function contexts; the Management Coordinator comprising a processor and a memory, the memory containing instructions executable by the processor such that the Management Coordinator is operable to:

maintain a mapping between: individual context data items comprised within the contexts of implementations of SON functions, and distributed implementations of SON functions that include the context data items in their function context; and

propagate changes made to the mapped context data items between the first coordination mechanism of the centralised implementations of SON functions and individual distributed implementations of SON functions in accordance with the mapping.

21. A Management Coordinator as claimed in claim 20, wherein the Management Coordinator is further operable to maintain a mapping by:

on instantiation of a centralised or distributed implementation of a SON function: obtaining metadata describing data items comprised within the function context of the function implementation; and

on instantiation of a distributed implementation of a SON function: associating a reference to the distributed implementation with mapping entries corresponding to context data items in the context of the distributed

implementation.

22. A Management Coordinator as claimed in claim 21 or 22, wherein the

Management Coordinator is further operable to maintain a mapping by:

on instantiation of a distributed implementation of a SON function:

23. A Management Coordinator as claimed in any one of the preceding claims, wherein the Management Coordinator is further operable to propagate changes made to the mapped context data items by:

for changes made by a distributed implementation of a SON function:

24. A Management Coordinator as claimed in any one of the preceding claims, wherein the Management Coordinator is further operable to implement a management coordination function for centralised and distributed SON functions.

25. A Management Coordinator as claimed in claim 24, wherein the management coordination function for centralised and distributed SON functions is a Virtualised Network Function, VNF, deployed on a Network Functions Virtualization Infrastructure, NFVI.

26. A Management Coordinator as claimed in any one of the preceding claims, wherein the management coordinator is further operable to carry out a method according to any one of claims 2 to 14.

27. A Management Coordinator for coordinating management of distributed and centralised implementations of Self Organising Network, SON, functions operable to interact with a network, wherein an implementation of a SON function is associated with a function context comprising data items used by the implementation to perform its function, and wherein centralised implementations of a SON function use a first coordination mechanism to share their function contexts; the management coordinator comprising:

a Context Mapper operable to maintain a mapping between: individual context data items comprised within the contexts of implementations of SON functions, and distributed implementations of SON functions that include the context data items in their function context; and

a Context Publisher and Function Coordinator operable to propagate changes made to the mapped context data items between the first coordination mechanism of the centralised implementations of SON functions and individual distributed

implementations of SON functions in accordance with the mapping.

28. A Management Coordinator as claimed in claim 27, wherein the Context Mapper is operable to:

on instantiation of a centralised or distributed implementation of a SON function: obtain metadata describing data items comprised within the function context of the function implementation; and

create an entry in the mapping for context data items described by the metadata for which an entry in the mapping does not already exist; and

on instantiation of a distributed implementation of a SON function:

associate a reference to the distributed implementation with mapping entries corresponding to context data items in the context of the distributed

implementation.

29. A Management Coordinator as claimed in claim 27 or 28, wherein the Function Coordinator is operable to:

on instantiation of a distributed implementation of a SON function: obtain metadata describing mechanisms for monitoring and setting values for data items in the context of the distributed implementation; and

generate and store an instance of a function mapper for the distributed implementation on the basis of the metadata, wherein the function mapper instance is operable to monitor at least one parameter relating to the distributed implementation and to issue instructions to the distributed implementation.