WO2016083524A1

WO2016083524A1 - Self-organizing network engine for mobility load balancing between wi-fi and cellular networks

Info

Publication number: WO2016083524A1
Application number: PCT/EP2015/077812
Authority: WO
Inventors: Alan Law; Tran Le MAI; Andrew Dunkin; Zhanhong Lu
Original assignee: Vodafone Ip Licensing Limited
Priority date: 2014-11-28
Filing date: 2015-11-26
Publication date: 2016-06-02
Also published as: GB201421192D0; GB2532788A

Abstract

The application relates to traffic steering and/or load balancing between Wi-Fi and cellular radio access telecommunications networks. Previous approaches needed traffic steering and load balancing functionality at a Wi-Fi controller which has to be physically connected to the rest of the radio access technologies trough a proprietary interface. As a result, a vast number of proprietary interfaces are present in the telecommunications network and this dramatically increases complexity in the network. This problem is overcome by the present application, in that a centralized self-organizing network, SON, engine (202) is deployed which is connected via an OSS (204) to the Wi-Fi controller (218) and a cellular radio access telecommunications network (216). In this way, the centralized SON engine, after having computed the best parameters for reconfiguring the network, can send the optimized parameters to the OSS which uses them to send corresponding commands via an open, i.e. non-proprietary interface, to the Wi-Fi controller. Thereby a physical connection between the Wi-Fi controller and a cellular network element is avoided.

Description

SELF-ORGANIZING NETWORK ENGINE FOR MOBILITY LOAD BALANCING BETWEEN WI-FI AND CELLULAR NETWORKS

Background

[0001 ] End users increasingly use Wi-Fi to access data services and, in general, use of Wi- Fi for telecommunications is becoming more popular. The use of Wi-Fi is increasing whilst the usage on cellular telecommunications networks is stabilizing. The term Wi-Fi is used here to refer to any local area wireless technology, including but not limited to wireless local area networks based on the IEEE 802.1 1 standards.

[0002] Wi-Fi is moving away from being an isolated technology to becoming a

complementary technology to cellular 2G, 3G and 4G telecommunications. To successfully integrate Wi-Fi with telecommunications technologies a traffic steering or load balancing mechanism is needed between Wi-Fi and cellular.

[0003] The embodiments described below are not limited to implementations which solve any or all of the disadvantages of known traffic steering and/or load balancing mechanisms between Wi-Fi and cellular telecommunications.

Summary

[0004] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

[0005] A computer-implemented method at a self-organizing network engine of a telecommunications network is described. The method comprises receiving Wi-Fi traffic load information from a Wi-Fi controller of the telecommunications network without the need for a direct physical connection between the Wi-Fi controller (or an additional network element connected to the Wi-Fi controller) and cellular network elements of the telecommunications network. Cellular traffic load data is also received. The self-organizing network engine is arranged so that if the Wi-Fi traffic load data, or cellular traffic load data, reaches a threshold, then the self-organizing network engine computes handover parameters to handover user equipment devices between the Wi-Fi network and the cellular network. The self-organizing network sends instructions to the telecommunications network to implement the handover parameters. [0006] According to an aspect of the invention there is provided a computer-implemented method at a self-organizing network engine of a telecommunications network, the method comprising: receiving Wi-Fi traffic load information from a Wi-Fi controller, or an additional network element connected to the Wi-Fi controller, of the telecommunications network without the need for a direct physical connection between the Wi-Fi controller or the additional network element and cellular network elements of the telecommunications network; receiving cellular traffic load information from at least one cellular network of the

telecommunications network; if the Wi-Fi traffic load data or the cellular traffic load data reaches a threshold, then computing handover parameters to handover user equipment devices between the Wi-Fi network and the cellular network; and sending instructions to the telecommunications network to implement the handover parameters. [0007] In an example the method comprises, receiving the cellular traffic load information from a plurality of cellular networks of different technologies.

[0008] In an example the method comprises computing the handover parameters using a mobility load balancing process.

[0009] In an example the method comprises accessing a technology preference type and taking the technology preference type into account during computation of the handover parameters.

[0010] In an example the method comprises receiving the Wi-Fi traffic load information from the Wi-Fi controller via a Wi-Fi operation support system and receiving the cellular traffic load information from a cellular operation support system, where the Wi-Fi controller is connected to the Wi-Fi operation support system but not to the cellular operation support system.

[0011 ] In an example the method comprises receiving the Wi-Fi traffic load information from an operation support system having an open connection to the Wi-Fi controller, an open connection being one which is not proprietary.

[0012] In an example the method comprises computing the handover parameters using a mobility load balancing process in an idle mode enabling camping users one of the cellular networks according to network load. [0013] In an example the method comprises computing the handover parameters using a mobility load balancing process in a connected mode.

[0014] In an example the method is repeated in a closed loop manner with variable cycle times. [0015] In another aspect of the invention there is provided a self-organizing network engine of a telecommunications network, the engine configured to automatically: receive Wi-Fi traffic load information from a Wi-Fi controller of the telecommunications network without the need for a direct physical connection between the Wi-Fi controller or an additional network element connected to the Wi-Fi controller, and cellular network element of the telecommunications network; receive cellular traffic load information from at least one cellular network of the

telecommunications network; if the Wi-Fi traffic load data or the cellular traffic load data reaches a threshold, then compute handover parameters to handover user equipment devices between the Wi-Fi network and the cellular network; and send instructions to the telecommunications network to implement the handover parameters.

[0016] For example, the engine is configured to receive the cellular traffic load information from a plurality of cellular networks of different technologies.

[0017] For example, the engine is configured to compute the handover parameters using a mobility load balancing process.

[0018] For example, the engine is configured to access a technology preference type and taking the technology preference type into account during computation of the handover parameters.

[0019] For example, the engine is configured to receive the Wi-Fi traffic load information from the Wi-Fi controller via a Wi-Fi operation support system and receive the cellular traffic load information from a cellular operation support system, where the Wi-Fi controller is connected to the Wi-Fi operation support system but not to the cellular operation support system.

[0020] For example, the engine is configured to receive the Wi-Fi traffic load information from an operation support system having an open connection to the Wi-Fi controller, an open connection being one which is not proprietary. [0021 ] For example, the engine is configured to compute the handover parameters using a mobility load balancing process in an idle mode enabling camping users one of the cellular networks according to network load.

[0022] For example, the engine is configured to compute the handover parameters using a mobility load balancing process in a connected mode.

[0023] For example, the engine is configured to operate in a repeating closed loop manner with variable cycle times.

[0024] In another aspect of the invention there is provided computer program code which when run on a computer causes the computer to perform a method according to any combination of the method examples mentioned above.

[0025] In another aspect of the invention there is provided a computer program product comprising computer readable code according to the example above.

[0026] In another aspect of the invention there is provided a carrier medium carrying computer readable code which when run on a computer causes the computer to perform a method according to any combination of the method examples mentioned above.

[0027] In another aspect of the invention there is provided a telecommunications network comprising:

[0028] a plurality of cellular networks of different radio access technologies;

[0029] a wireless local area network having a controller connected to a plurality of access points;

[0030] a self-organizing network engine as described in any of the paragraphs above about self-organizing network engines.

[0031 ] For example, the controller is connected to a wireless operation support system which is separate from an operation support system of the cellular networks.

[0032] For example, the controller is connected to an operation support system of the wireless local area network and the cellular networks, by an open, non-proprietary connection.

[0033] The methods described herein may be performed by software in machine readable form on a tangible storage medium e.g. in the form of a computer program comprising computer program code means adapted to perform all the steps of any of the methods described herein when the program is run on a computer and where the computer program may be embodied on a computer readable medium. Examples of tangible (or non-transitory) storage media include disks, thumb drives, memory cards etc. and do not include propagated signals. The software can be suitable for execution on a parallel processor or a serial processor such that the method steps may be carried out in any suitable order, or simultaneously.

[0034] This acknowledges that firmware and software can be valuable, separately tradable commodities. It is intended to encompass software, which runs on or controls "dumb" or standard hardware, to carry out the desired functions. It is also intended to encompass software which "describes" or defines the configuration of hardware, such as HDL (hardware description language) software, as is used for designing silicon chips, or for configuring universal programmable chips, to carry out desired functions.

[0035] The preferred features may be combined as appropriate, as would be apparent to a skilled person, and may be combined with any of the aspects of the invention. Brief Description of the Drawings

[0036] Embodiments of the invention will be described, by way of example, with reference to the following drawings, in which:

[0037] Figure 1 is a schematic diagram of a telecommunications network comprising a Wi-Fi controller and one or more cellular radio access technologies; [0038] Figure 2 is a schematic diagram of the telecommunications network of Figure 1 with an additional network element which orchestrates a Wi-Fi controller and one or more cellular radio access technologies;

[0039] Figure 3 is a schematic diagram of the telecommunications network of Figure 1 with a centralized self-organizing network node and OSS(operation support system) node; [0040] Figure 4 is a schematic diagram of self-organizing interworking procedure between a self-organizing network engine, an operation support system and telecommunications network;

[0041 ] Figure 5 is a schematic diagram of the arrangement of figure 4 where the telecommunications network comprises a Wi-Fi controller connected to the operation support system by an open interface; [0042] Figure 6 is a schematic diagram of the arrangement of figure 4 where the telecommunications network comprises a Wi-Fi controller connected to a Wi-Fi operation support system and where cellular elements are connected to a separate operation support system; [0043] Figure 7 is a flow diagram of a method at a self-organizing network engine to carry out traffic load balancing between Wi-Fi and cellular;

[0044] Figure 8 is a schematic diagram of a computing device implementing a self- organizing network engine;

[0045] Common reference numerals are used throughout the figures to indicate similar features.

Detailed Description

[0046] Embodiments of the present invention are described below by way of example only. These examples represent the best ways of putting the invention into practice that are currently known to the Applicant although they are not the only ways in which this could be achieved. The description sets forth the functions of the example and the sequence of steps for constructing and operating the example. However, the same or equivalent functions and sequences may be accomplished by different examples.

[0047] The inventors have found that it is possible to improve traffic steering and/or load balancing between Wi-Fi and cellular radio access telecommunications networks by using a self-organizing network engine and without the need for a direct physical connection between a Wi-Fi controller and cellular network elements of the telecommunications network, or between an additional network element, which orchestrates a Wi-Fi controller, and cellular network elements of the telecommunications network. The self-organizing network engine is able to select the most appropriate technology (2G/ 3G/ 4G or Wi-Fi). By having better traffic steering and/or load balancing overall telecommunications performance is improved and faults and the need for maintenance is reduced. By using a self-organizing network engine the telecommunications network operator has better control over traffic steering and load balancing between Wi-Fi and cellular than previously possible. By removing the need for a direct physical connection between a Wi-Fi controller (or an additional network element which orchestrates the Wi-Fi controller) and cellular network elements a simpler deployment is given than was previously possible and multi-vendor environments can be easily accommodated.

[0048] Previous approaches to traffic steering and/or load balancing between Wi-Fi and cellular have needed traffic steering and load balancing functionality at a Wi-Fi controller (or an additional network element) which has to be physically connected to the rest of the radio access technologies (2G/3G/4G) through a proprietary interface. As a result a vast number of proprietary interfaces are present in the telecommunications network and this dramatically increases complexity within the network. [0049] Many previous approaches to traffic steering and/or load balancing between Wi-Fi and cellular use applications or clients installed at the user equipment (UE). These UE (also referred to as terminal) based approaches make it hard for the network operator to control load balancing between Wi-Fi and cellular.

[0050] A Wi-Fi controller is a communications network node which manages a plurality of wireless access points, either via wireless or wired connections with the wireless access points. For example, by managing handover of a user equipment between the plurality of wireless access points. A wireless access point is a node which connects between a wireless local area network and one or more wireless user equipment devices which are within its range. [0051 ] A self-organizing network (SON) engine comprises computer-implemented functionality for executing an optimization algorithm which uses efficient methods to search huge numbers of combinations of possible values of parameters of a telecommunications network (such as a 2G, 3G, 4G mobile radio access network), to find solutions which are optimal according to one or more assessment metrics. For example, the parameters include but are not limited to hand-over parameters, antenna tilt, pilot transmission power, common channel transmission power, automatic neighbor relations, network load and others. The assessment metric may comprise thresholds and or criteria to be met by telecommunications network performance data. Examples of telecommunications network performance data include but are not limited to key performance indicators such as dropped call rate, call setup failure rate. Self-organizing network engine functionality may be centralized or distributed through a telecommunications network. Hybrid deployments using a mix of centralized and distributed SON technology may also be used. SON has been defined in 3GPP release 8 and other onwards specifications (e.g. release 9 and 10).

[0052] An operation support system (OSS) is computer-implemented apparatus interfacing between a SON engine and telecommunications infrastructure. An example OSS is described in more detail below. OSS collects network data such as configuration

measurement data, performance measurement data and fault measurement data from telecommunications networks, and forwards these data to SON engine to evaluate the network performance and provide optimized radio network parameters. [0053] The Third Generation Partnership Project (3GPP) introduced into Release 8 the concept of a Self-Organizing Network (SON), an intelligent platform that automatically optimizes 2G, 3G and 4G networks, and defined a set of use cases that govern a network including the planning, deployment, optimization and maintenance activities. 3GPP does not specify how to implement these use cases: SON vendors may implement the use cases using their own proprietary algorithms. The use cases include Automatic Neighbor Relations (ANR), Coverage and Capacity Optimization (CCO), Mobility Load Balancing (MLB), Mobility Robustness Optimization (MRO).

[0054] Automatic Neighbor Relations (ANR) is designed to optimize the neighbor relations by adding missing neighbor relations, deleting redundant neighbor relations, and prioritizing neighbor relations, in order to reduce the number of user calls dropped due to missing or incorrect neighbor relations. Correct and up-to-date neighboring lists will increase the number of successful handovers and minimize the number of dropped calls.

[0055] Coverage and Capacity Optimization (CCO) aims to optimize parameters relating to transmission power, antenna tilting and handover in order to balance the network coverage, capacity and quality. Specific examples of parameters to be optimized during CCO include antenna remote electronic tilt (RET), primary CPICH (Common Pilot Channel) power, BCH (Broadcast Channel) power, AICH (Acquisition Indicator Channel) power, PCH (Paging Channel)power, PICH (Paging Indication Channel) power, idle mode inter-RAT reselect threshold, idle mode inter-frequency reselect threshold, inter-RAT handover threshold, intra- frequency mobility parameters, and HSDPA (High Speed Downlink Packet Access) power.

[0056] Mobility Load Balancing (MLB) seeks to optimize the pilot transmission power, common channels power, and handover parameters to balance traffic or network load between different sites, different frequency layers, and different Radio Access Technologies (RAT) (2G/3G/LTE). MLB allows cells suffering congestion to transfer load to other cells which have spare resources, and includes load reporting to exchange information about load level and available capacity. In case of inter-RAT MLB, a load reporting protocol may be used to transfer information between base stations of different radio access technologies, so that the capacities of the different technologies can be compared and weighed against each other.,

[0057] MRO (Mobility Robustness Optimization) is a solution for automatic detection and correction of errors in the mobility configuration, and is designed to optimize the handover parameters to reduce the Radio Link Failure (RLF) due to handover occurring too early, too late, to an incorrect cell, and due to the so-called "ping-pong effect". Specific examples of parameters to be optimized during MRO include cell individual offset (CIO), time to trigger (TTT), trigger thresholds, hysteresis value for ping-pong control, neighbor list relation, speed- dependent parameters, antenna RET, and idle mode parameters to avoid immediate handover trigger when transitioning from idle to active states.

[0058] Figure 1 is a schematic diagram of a telecommunications network comprising a Wi- Ficontroller 102 and one or more cellular radio access technologies (2G/3G/4G). In this example, thousands of end users are at a stadium 108 for a sports event or concert. The end users have individual user equipment devices which are able to receive services over the telecommunications network 100. A plurality of Wi-Fi access points (AP) 106 are present at the stadium 108 and are controlled by Wi-Fi controller 102 by wired or wireless connections. A user equipment device at the stadium is able to receive services either via Wi-Fi AP 106 or via a nearby base station 104 of one of the cellular radio access technologies.

[0059] Figure 2 is a schematic diagram of the telecommunications network of Figure 1 with an additional network element 200 which orchestrates the Wi-Fi controller 102 and one or more cellular radio access technologies (2G/3G/4G). The additional network element has a direct physical connection between the Wi-Fi controller and cellular network elements 100 to enable it to orchestrate the different elements of the telecommunications network

(2G/3G/4G/Wi-Fi).

[0060] In various embodiments described in this document, a self-organizing network engine automatically controls traffic steering and/or load balancing between the Wi-Fi controller and the base station 104 which improves the user experience. For example, the self-organizing network engine controls whether a given user equipment connects to the Wi-Fi controller or to the base station 104. The self-organizing network engine achieves this without the need for a direct physical connection between the Wi-Fi controller (or an additional network element) 102 and network elements of the individual radio access technologies. The self-organizing network engine is centralized functionality connected to a telecommunications network operation support system (OSS) and managing both Wi-Fi and cellular networks. Figure 3 is a schematic diagram of the telecommunications network of Figure 1 with a centralized self- organizing network engine 202. The centralized self-organizing network engine 202 is connected to telecommunications infrastructure 200 of the telecommunications network 100 via an operation support system 204. The centralized self-organizing network engine 202 is computer-implemented using, for example, a server or a group of servers. Figure 8 shows an example of a computing-based device implementing a self-organizing network engine.

[0061 ] At least one Wi-Fi controller 218 is connected to the telecommunications

infrastructure 200 and manages a plurality of access points 218. [0062] The operation support system 204 is also computer-implemented and is arranged to interface with telecommunications infrastructure 200 comprising different types of telecommunications network nodes. These include base stations, switches, and routers. Telecommunications infrastructure 200 is in communication with base stations of a cellular telecommunications network such as base stations 210, 212, 216, each base station having a footprint indicated schematically in the figure as a hexagonal cell. User equipment devices 214 are able to receive services from the telecommunications network 100 such as voice, video and other services.

[0063] The operation support system 204 is configured to receive data from the

telecommunications network such as performance statistics, traffic loads, and other data.

The operation support system 204 may compute higher level statistics from the performance data it receives, for example, by aggregating data after filtering out outliers. The operation support system 204 may probe the telecommunications network to obtain the performance data in some examples. The operation support system 204 comprises interfaces for interoperating with various different types of telecommunications network node, such as base stations and/or other nodes in the telecommunications infrastructure. In this way the operation support system is able to issue commands to telecommunications network nodes in order to control the behavior of those nodes.

[0064] In some examples a policy node 206 is present, although this is not essential. The policy node comprises a store holding profiles, records or policy data. For example, there may be profiles for any one or more of: individual users, groups of users, specified types of service. A profile may comprise quality of service requirements such as thresholds or criteria which network performance statistics are to meet.

[0065] Figure 4 shows a telecommunications network 400 which outputs network performance statistics data 410, including configuration management data, performance management data, fault management data, and user measurement data to an operation support system 204. The operation support system 204 calculates higher level performance data 402, for example by aggregating and/or filtering the data 410. The operation support system sends the higher level performance data 402 to a SON engine 202. The SON carries out an optimization to search for a best set of values of radio parameters, or other network parameters 406 for reconfiguring the telecommunications network 400. The SON sends the optimized parameters 406 to the OSS which uses them to send commands 408 to nodes of the telecommunications network so that the reconfiguration is implemented.

[0066] Figure 5 is a schematic diagram of the arrangement of figure 4 where the telecommunications network comprises a Wi-Fi controller 508 connected to the cellular operation support system 504 by an open interface. An open interface is one which is not proprietary and which may be used by different vendors. The Wi-Fi controller 508 is itself connected to a plurality of access points 506.

[0067] The telecommunications network comprises a plurality of different types of cellular network element. A non-exhaustive list of examples is: small cell gateway 510, base station controller (BSC) 512, radio network controller (RNC) 514 and an end node B (eNB) 516. Each of the cellular network elements is connected to the cellular operation support system (OSS) 504.

[0068] The OSS is connected to a centralized self-organizing network engine 500 in this example, via a standard northbound interface (such as Itf-N 502).

[0069] In the arrangement of figure 5, because the connection between the Wi-Fi controller and the OSS is an open connection the complexity of previous approaches using proprietary connections is removed. Also, because the connection between the Wi-Fi controller and the OSS is open there is no need for physical connection to link the Wi-Fi controller (or an additional network element) to each cellular network element such as small cell gateway 510, BSC 512, RNC 514 and eNB 516.

[0070] Traffic load statistics and/or other network statistics and performance data are collected by the Wi-Fi controller and the cellular network elements 510, 512, 514, 516. For example, these traffic load statistics include radio receiving/sending rate, single user uplink/downlink rate from Wi-Fi controller, and network code load, power load, resource block usage etc. from cellular network elements. This traffic load data and/or network performance data are sent to the OSS 504. The OSS forwards the data to the centralized SON server so that the SON server has information about traffic load and other performance in Wi-Fi and cellular networks. In some examples the OSS may filter the traffic load statistics and/or other network performance data to remove errors or outliers. In some examples the OSS may aggregate the traffic load statistics or compute higher level statistics from the data it receives.

[0071 ] The SON 500 is able to use the network statistics to carry out mobility load balancing in real time and to send commands to the Wi-Fi controller and cellular network elements. This is described in more detail with reference to figure 7 below. [0072] The architecture of figure 5 is suited for single vendor scenarios where the Wi-Fi controller is connected to the same cellular vendor OSS. However, as there is an open interface between the Wi-Fi controller and the cellular OSS, this potentially can be used for multi-vendor deployments. [0073] Figure 6 shows another embodiment where two separate OSSs are used: a Wi-Fi OSS 600 and a cellular OSS 504. In this example, it is not essential to have an open interface between the Wi-Fi controller 508 and the Wi-Fi OSS 600. However, by using two separate OSSs, each having access to the SON, it is possible for the SON to automatically control traffic steering and/or load balancing between Wi-Fi and cellular without the need for direct connections between the Wi-Fi controller and cellular network elements.

[0074] As with figure 5, the telecommunications network of figure 6 comprises a plurality of different types of cellular network element. A non-exhaustive list of examples is: small cell gateway 510, base station controller (BSC) 512, radio network controller (RNC) 514 and an end node B (eNB) 516. Each of the cellular network elements is connected to a cellular operation support system (OSS) 504. A Wi-Fi controller 508, connected to a plurality of access points 506, is connected to Wi-Fi OSS 600. Each OSS 600, 504 is connected to the SON for example, via a standard northbound interface (such as Itf-N 602 and Itf-N 502).

[0075] The deployment of figure 6 is particularly suited to multi-vendor scenarios. It is beneficial where a Wi-Fi controller cannot be connected directly to a cellular OSS system.

The Wi-Fi OSS is introduced to connect the Wi-Fi system to a SON engine/server. The Wi-Fi OSS has similar functionality to a cellular OSS, but it manages Wi-Fi networks only. This architecture is more flexible and makes multi-vendor implementations feasible. The SON engine may send commands to both the cellular OSS and the Wi-Fi OSS. [0076] Figure 7 is a flow diagram of a method at a self-organizing network engine. This method may be used with the deployment of figure 5 or the deployment of figure 6. Traffic load statistics 700 are received from the Wi-Fi controller. For example, these statistics may comprise one or more of: user equipment throughput, number of user equipment devices, signal quality). The Wi-Fi traffic load statistics 700 are input to the Wi-Fi OSS 600 where that is available. The Wi-Fi traffic load statistics 700 may be input to the OSS 504 where a single OSS is used (such as in the deployment of figure 5).

[0077] 2G traffic load statistics 702 are received from 2G network elements where 2G network elements are present. For example, 2G traffic load statistics may comprise one or more of: circuit switch traffic in Erlangs, circuit switch traffic in volumes). [0078] 3G traffic load statistics 704 are received from 3G network elements where 3G network elements are present. For example, 3G traffic load statistics may comprise one or more of: code load, hardware load, and power load. [0079] 4G traffic load statistics 706 are received from 4G network elements where 4G network elements are present. For example, 4G traffic load statistics may comprise percentage of physical resource blocks (PRBs) being used.

[0080] The OSS 504 and the Wi-Fi OSS 600 forward the received traffic load data to the SON 500 (after aggregation, filtering or computing higher level statistics in some examples). The SON then checks 708 whether the Wi-Fi load reaches a threshold. If not, then no action is taken by the SON. If yes, then the SON checks 712 which cellular network is available. This is done by assessing the traffic load statistics received from the cellular network elements. [0081 ] If cellular network traffic load is not reaching the threshold and can accommodate more users, the SON them computes 714 optimized handover parameters to handover more users from Wi-Fi to cellular networks that it identified as being available at step 712. The optimized handover parameters are sent to the OSS (Wi-Fi OSS 600 and/or OSS 504) and used to implement the handover in the telecommunications network. This handover may be referred to as a reconfiguration of the telecommunications network.

[0082] In some examples the SON computes 714 the optimized handover parameters by running mobility load balancing functionality automatically according to the real traffic load in real time. In some examples the mobility load balancing functionality is run in idle mode. In some examples the mobility load balancing functionality is run in connected mode. In idle mode, the optimized parameters enable camping users at an optimal network layer (i.e. 2G, 3G, LTE and Wi-Fi) according to network load. In connected mode, the mobility load balancing functionality optimizes network parameters such as pilot power and handover parameters, to handover users between cellular and Wi-Fi networks. This may be achieved intelligently and automatically in a closed-loop manner with variable cycle times from daily, hourly down to 15 minutes. The SON proceeds to measure 716 cellular and Wi-Fi network key performance indicators (KPIs) by asking the OSS 504 and/or Wi-Fi OSS 600 for KPI data. The SON uses the KPI data to check 718 whether the network performance in both Wi-Fi and cellular networks are improved or not. If the optimized handover parameters result in a detriment in KPI data, then the SON commands the OSS (and Wi-Fi OSS) to roll back the most recent reconfiguration of the network to the previous configuration.

[0083] If no roll back occurs the optimized handover parameters are kept 720 and used for a complete optimization cycle (such as 15 minutes or other time interval).

[0084] The method of figure 7 may be adapted for cellular to Wi-Fi load balancing. [0085] In some examples, the SON engine also has access to technology preference type data. It may be arranged to use the technology preference type data to influence the mobility load balancing process so that user equipment devices are steered to particular technologies. This allows generic user equipment devices to be released, and the SON engine can control the user equipment device connection behavior or even remotely change this in the field as the network develops.

[0086] The method of figure 7 may be used for massive events handling in some examples. For example, in the stadium scenario of figure 1 the method of figure 7 may be used with the architecture of figures 5 or 6 to automatically balance the traffic load between Wi-Fi and cellular. This improves end user experience.

[0087] Figure 8 illustrates various components of an exemplary computing-based device 800 which may be implemented as any form of a computing and/or electronic device, and in which embodiments of a self-organizing network engine may be implemented.

[0088] Computing-based device 800 comprises one or more processors 802 which may be microprocessors, controllers or any other suitable type of processors for processing computer executable instructions to control the operation of the device in order to receive data from an OSS and compute optimized parameters of a telecommunications network. In some examples, for example where a system on a chip architecture is used, the processors 802 may include one or more fixed function blocks (also referred to as accelerators) which implement a part of the method of figure 7 in hardware (rather than software or firmware).

Platform software comprising an operating system 804 or any other suitable platform software may be provided at the computing-based device to enable application software to be executed on the device. Software comprising a self-organizing network engine 808 may be provided at the computing-based device and data store 810 may hold telecommunications network parameters, network performance data, user measurement data or other data.

[0089] The computer executable instructions may be provided using any computer-readable media that is accessible by computing based device 800. Computer-readable media may include, for example, computer storage media such as memory 812 and communications media. Computer storage media, such as memory 812, includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Computer storage media includes, but is not limited to, RAM, ROM, EPROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information for access by a computing device. In contrast, communication media may embody computer readable instructions, data structures, program modules, or other data in a modulated data signal, such as a carrier wave, or other transport mechanism. As defined herein, computer storage media does not include communication media. Although the computer storage media (memory 812) is shown within the computing-based device 800 it will be appreciated that the storage may be distributed or located remotely and accessed via a network or other communication link (e.g. using communication interface 814).

[0090] The computing-based device 800 also comprises an input/output controller 816 arranged to output display information to a display device 818 which may be separate from or integral to the computing-based device 800. The display information may provide a graphical user interface. The input/output controller 816 is also arranged to receive and process input from one or more devices, such as a user input device 820 (e.g. a mouse or a keyboard). This user input may be used to set thresholds or criteria, configure optimization algorithms, and view optimization results. In an embodiment the display device 818 may also act as the user input device 820 if it is a touch sensitive display device. The input/output controller 816 may also output data to devices other than the display device, e.g. a locally connected printing device.

[0091 ] The term 'computer' is used herein to refer to any device with processing capability such that it can execute instructions. Those skilled in the art will realize that such processing capabilities are incorporated into many different devices and therefore the term 'computer' includes PCs, servers, mobile telephones, personal digital assistants and many other devices.

[0092] Those skilled in the art will realize that storage devices utilized to store program instructions can be distributed across a network. For example, a remote computer may store an example of the process described as software. A local or terminal computer may access the remote computer and download a part or all of the software to run the program.

Alternatively, the local computer may download pieces of the software as needed, or execute some software instructions at the local terminal and some at the remote computer (or computer network). Those skilled in the art will also realize that by utilizing conventional techniques known to those skilled in the art that all, or a portion of the software instructions may be carried out by a dedicated circuit, such as a DSP, programmable logic array, or the like.

[0093] Any range or device value given herein may be extended or altered without losing the effect sought, as will be apparent to the skilled person.

[0094] It will be understood that the benefits and advantages described above may relate to one embodiment or may relate to several embodiments. The embodiments are not limited to those that solve any or all of the stated problems or those that have any or all of the stated benefits and advantages.

[0095] Any reference to 'an' item refers to one or more of those items. The term 'comprising' is used herein to mean including the method blocks or elements identified, but that such blocks or elements do not comprise an exclusive list and a method or apparatus may contain additional blocks or elements.

[0096] The steps of the methods described herein may be carried out in any suitable order, or simultaneously where appropriate. Additionally, individual blocks may be deleted from any of the methods without departing from the spirit and scope of the subject matter described herein. Aspects of any of the examples described above may be combined with aspects of any of the other examples described to form further examples without losing the effect sought.

[0097] It will be understood that the above description of a preferred embodiment is given by way of example only and that various modifications may be made by those skilled in the art. Although various embodiments have been described above with a certain degree of particularity, or with reference to one or more individual embodiments, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the spirit or scope of this invention.

Claims

A computer-implemented method at a self-organizing network engine of a telecommunications network, the method comprising: receiving Wi-Fi traffic load information from a Wi-Fi controller, or an additional network element connected to the Wi-Fi controller, of the telecommunications network without the need for a direct physical connection between the Wi-Fi controller or the additional network element and cellular network elements of the

telecommunications network; receiving cellular traffic load information from at least one cellular network of the telecommunications network; if the Wi-Fi traffic load data or the cellular traffic load data reaches a threshold, then computing handover parameters to handover user equipment devices between the Wi-Fi network and the cellular network; and sending instructions to the telecommunications network to implement the handover parameters.

A method as claimed in claim 1 comprising, receiving the cellular traffic load information from a plurality of cellular networks of different technologies.

A method as claimed in claim 1 or claim 2 comprising computing the handover parameters using a mobility load balancing process.

A method as claimed in any preceding claim comprising accessing a technology preference type and taking the technology preference type into account during computation of the handover parameters.

A method as claimed in any preceding claim comprising receiving the Wi-Fi traffic load information from the Wi-Fi controller via a Wi-Fi operation support system and receiving the cellular traffic load information from a cellular operation support system, where the Wi-Fi controller is connected to the Wi-Fi operation support system but not to the cellular operation support system.

A method as claimed in any of claims 1 to 4 comprising receiving the Wi-Fi traffic load information from an operation support system having an open connection to the Wi-Fi controller, an open connection being one which is not proprietary.

7. A method as claimed in any preceding claim comprising computing the handover parameters using a mobility load balancing process in an idle mode enabling camping users one of the cellular networks according to network load.

8. A method as claimed in any preceding claim comprising computing the handover parameters using a mobility load balancing process in a connected mode.

9. A method as claimed in any preceding claim which is repeated in a closed loop

manner with variable cycle times.

10. A self-organizing network engine of a telecommunications network, the engine

configured to automatically: receive Wi-Fi traffic load information from a Wi-Fi controller of the

telecommunications network without the need for a direct physical connection between the Wi-Fi controller or an additional network element connected to the Wi-Fi controller, and cellular network element of the telecommunications network; receive cellular traffic load information from at least one cellular network of the telecommunications network; if the Wi-Fi traffic load data or the cellular traffic load data reaches a threshold, then compute handover parameters to handover user equipment devices between the Wi- Fi network and the cellular network; and send instructions to the telecommunications network to implement the handover parameters.

1 1 . A self-organizing network engine as claimed in claim 10 configured to receive the cellular traffic load information from a plurality of cellular networks of different technologies.

12. A self-organizing network engine as claimed in claim 10 or claim 1 1 configured to compute the handover parameters using a mobility load balancing process.

13. A self-organizing network engine as claimed in any of claims 10 to 12 configured to access a technology preference type and taking the technology preference type into account during computation of the handover parameters.

14. A self-organizing network engine as claimed in any of claims 10 to 13 configured to receive the Wi-Fi traffic load information from the Wi-Fi controller via a Wi-Fi operation support system and receive the cellular traffic load information from a cellular operation support system, where the Wi-Fi controller is connected to the Wi-Fi operation support system but not to the cellular operation support system.

15. A self-organizing network engine as claimed in any of claims 10 to 13 configured to receive the Wi-Fi traffic load information from an operation support system having an open connection to the Wi-Fi controller, an open connection being one which is not proprietary.

16. A self-organizing network engine as claimed in any of claims 10 to 15 configured to compute the handover parameters using a mobility load balancing process in an idle mode enabling camping users one of the cellular networks according to network load.

17. A self-organizing network engine as claimed in any of claims 10 to 15 configured to compute the handover parameters using a mobility load balancing process in a connected mode.

18. A self-organizing network engine as claimed in any of claims 10 to 17 which is

configured to operate in a repeating closed loop manner with variable cycle times.

19. Computer program code which when run on a computer causes the computer to

perform a method according to any of claims 1 to 9.

20. A computer program product comprising computer readable code according to claim 19.

21 . A carrier medium carrying computer readable code which when run on a computer causes the computer to perform a method according to any of claims 1 to 9.

22. A telecommunications network comprising: a plurality of cellular networks of different radio access technologies; a wireless local area network having a controller connected to a plurality of access points; a self-organizing network engine as claimed in any of claims 10 to 18.

23. The telecommunications network of claim 22 wherein the controller is connected to a wireless operation support system which is separate from an operation support system of the cellular networks.

24. The telecommunications network of claim 22 wherein the controller is connected to an operation support system of the wireless local area network and the cellular networks, by an open, non-proprietary connection.