mobile users [3]. The most significant near term impact of reconfigurability is likely to be in the field of service and applications innovation, as a tool to allow rapid ...
Advanced Location Information Management Scheme for Supporting Flexible Service Provisioning in Reconfigurable Mobile Networks Spyridon Panagiotakis, Maria Koutsopoulou, Athanasia Alonistioti National and Kapodistrian University of Athens, Department of Informatics and Telecommunications, Communication Networks Laboratory, 157 84 Athens, Greece Tel: +30 1 72 75 334, emails: {spanag, mkoutsop, nancy}@di.uoa.gr ABSTRACT The urgency for service differentiation, customisation and personalisation in the market of 3G mobile services and applications has boosted the activities of many standards groups and Telecommunication companies and institutions to introduce advanced frameworks and architectures for the support of flexible service provision. Important feature in such architectures is the location information management, key aspect in future mobile systems and networks that enables new approaches in service provision, customisation and personalisation. In the context of developing an innovative open flexible service provision architecture, the advanced location management feature of the platform is introduced in this paper. The location management functionality presented exploits the mobility and location information to provide mobility and location aware service management and provision in 3G networks and beyond. I. INTRODUCTION With the evolution of broadband and 3rd generation (3G) mobile communications as well as the imminence of 4G systems, the reconfigurability concept has been heralded as potentially offering a pragmatic solution for the provision of a wide range of sophisticated services to mobile users [3]. The most significant near term impact of reconfigurability is likely to be in the field of service and applications innovation, as a tool to allow rapid and flexible service customization and new degrees of operator differentiation. Within that scope, the importance of localisation [4] as a primary concept for service customisation, network reconfigurability and operator differentiation has boosted the activities of many Telecommunication companies and institutions to develop or integrate positioning systems into their networks. The exploitation of location information presents a powerful new dimension to the range of information services that can be offered. By combining positional mechanisms with location and mobility specific user information, it is possible to offer truly customized personal communication services through the mobile phone or other mobile devices [4]. Hence, the provision of an integrated framework for the support and management of flexible service provision, reconfigurability control aspects, charging [2] and location information management in a coherent manner is
a very important issue for the emergence of advanced service provision in 3G systems and beyond [2][3][4]. Within that scope, the business models to be adopted in the new era are encompassing the accommodation of third party Value Added Service Providers (VASPs), which will be able to offer their services through open operator’s networks under the respective business agreements. The challenge for network operators is to attract and engage third-party application providers while protecting their networks from harm. By using intelligent service mediation [6] it is envisioned [7] that network operators will be enabled to open their networks safely through policy management techniques, as well as to reduce the complexity involved in delivering applications developed by third parties over public switched and mobile networks. In this paper at first a generic and open framework for intelligent service provision and location information management is introduced and then the functional aspects adopted and the interactions required among its constituent entities to accomplish location aware service deployment and discovery as well as effective locationbased charging are discussed. The proposed entities and framework have partially been developed under the IST project MOBIVAS while respective simulations and trials have been performed. II. A FLEXIBLE FRAMEWORK FOR RECONFIGURABLE SERVICE PROVISIONING AND LOCATION INFORMATION MANAGEMENT To support the demand of future communications for efficient and personalised service provision the standard UMTS infrastructure should be supplemented with intelligent components. Figure 1, depicts the general architecture and an example physical placement of the Reconfiguration Control and Service Provision Platform (RCSPP) to meet requirements for the 3G and beyond era. It is assumed that the independent Value Added Service Providers (VASPs) will offer their Value Added Services (VAS) using the transport service provided by the underlying UMTS network. The RCSPP constitutes an integrated distributed software framework for reconfigurable deployment and management of VAS offered to mobile users as well as charging for their usage [2][3]. The framework introduces several components involved in service provisioning namely, the Reconfiguration Control and Service Provision Manager (RCSPM), the Charging Accounting
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Figure 1. General architecture and example physical placement of the RCSPP framework and Billing (CAB) System and the Metering Devices (MDs). Although business roles may be integrated to one entity (e.g. the RCSPP provider and the network access provider business roles may be undertaken by the mobile operator), we see that the business domains can also be physically separated. In more detail: The RCSP Manager (RCSPM) may reside in a Third Party domain. It co-ordinates the required procedures for dynamic application deployment and personalized, consistent and reconfigurable discovery, provision and execution of VAS to mobile users [3]. For that reason, it maintains a database with information about the services offered by the platform (the Service DB), as well as user profile data. The RCSPM hosts the Reconfiguration and the Location Manager modules. The former is responsible for interacting with other components of the proposed architecture (e.g. MDs) in order to configure them properly as well as to perform reconfiguration actions on them. Reconfiguration actions are based on policies (e.g. QoS or metering policies) tailored to user location, terminal capabilities, user preferences and usage data. On the other hand, the Location Manager interacts with the location information’s sources of the underlying network infrastructure (e.g. the LCS Server) to track the location and mobility of the subscribers. Then, location and mobility data along with user preferences from the user profiles, network performance data from the underlying Basic Network Management Layer and usage data from users and VASPs are processed properly to form new advanced location aware services and policies (e.g. location based charging, address based location retrieval).
Hence, the Location Manager enriches the service provisioning approach adopted by the RCSPP with location aware features enabling better customisation and personalisation of the whole service offering. Location tracking takes place with respect to the user privacy settings included into the user profile [1][5]. Since the RCSPP administratively may be situated on and managed by entities independent to the operator network, interactions among the modules of the platform and Basic Network Elements, such as the HSS, the LCS server [1], the Messaging Server, etc., should take place through open network interfaces. Various industry initiatives, such as OSA [6], PARLAY, and JAIN, address the introduction of open network interfaces to third party providers. Common to all these architectures is the provision of a Basic Network Management Layer by the mobile operator, which acts as gateway (mediator) between Third Parties and provided basic network services [7]. Hence, in order for the RCSPP to access the network services offered by the underlying network infrastructure, interaction with the Basic Network Management Layer provided by the mobile operator is required. By accessing the standard open network interface provided by the Basic Network Management Layer, the RCSPP is then able to build its services based on network features and functionality offered by the network operator. The MDs [2] are dynamically configured by the RCSPM through policies to process and monitor the traffic over the IP layer as well as to meter data about resource consumption in the network (e.g. transmitted volume). In the proposed architecture the MDs are located at the edge
of the Network Access Provider so that they process all traffic between VASPs and the end users. The collected metering data are formatted into appropriate records, the VAS Data Records (VASDRs) and sent to the CAB for further processing [2]. The VASDRs, apart from calculating of charges, are also used by the CAB for the retrieval of statistical information, such as the VAS that a specific user currently executes. The functionality of MDs is under the supervision of the MD Reconfiguration Manager, which is responsible for the policy-based configuration and reconfiguration of the MDs. Since it is likely the MDs to be included into the standard network infrastructure, access to the reconfiguration of MDs should be offered to the RCSPM and other authorised entities through a standard open API provided by the MD Reconfiguration Manager [2]. The MD Reconfiguration Manager mediates between authorised entities and MDs to securely grant the MD services to the respective parties (e.g. VASPs). Since reconfiguration of MDs is policy based, communication with the MDs is built upon the common protocols for policy provisioning such as the COPS or COPS-PR. The MD Reconfiguration Manager maps all incoming calls on the aforementioned open interface to the appropriate COPS/COPS-PR messages for interacting with MDs. The proposed interface for the MD reconfiguration’s purposes includes methods that enable: Creation/Modification/Deletion of Policy Classes (implemented by the monitorIPTrafficReq(), modifyIPTrafficMonitoringReq(), cancelIPTrafficMonitoringReq(), createPolicyReq(), modifyPolicyReq(), cancelPolicyReq() methods). Activation/De-activation of policies (implemented by the directApplyPolicyReq(), directCancelPolicyReq(), directCollectMeteringDataReq() methods ). Creation/Modification/Deletion of Policy Events (implemented by the createPolicyEventReq(), modifyPolicyEventReq(), cancelPolicyEventReq() methods). Registration/Deregistration for event notification (implemented by the registerEventNotificationReq(), cancelEventNotificationReq() methods). Handling of event notification from the network (implemented by the eventNotification() method). Gathering of performance and policy related statistics from the operation of MDs on policy classes and events (implemented by the sentPerformanceDataReq() method). Ability to make service requests from policy enabled VAS e.g., for improved QoS values. The CAB system [2] is responsible for the overall control of the charging process, providing advanced charging, accounting and billing services to VASPs and end users. To elaborate, the CAB collects charging information from both network infrastructure (in the form of Charging Data Records (CDRs) from CGF and CCF) and MDs (in the form of VASDRs), applies the appropriate pricing model, calculates the portions that are due to each business entity and produces a single itemised bill to each subscriber. Additionally, the CAB provides advanced charging services through open APIs in order to enable the RCSPM and independent VASPs to apply pricing policies
dynamically, to retrieve statistical information concerning the VAS usage (e.g. the users that currently execute a specific VAS, or the VAS that are currently executed by a specific user), to add content based charges and to be informed about current status of their VAS revenues. III. INTERACTIONS AND IMPLEMENTATION DETAILS FOR MOBILITY AND LOCATION AWARE SERVICE PROVISIONING A. Location aware Service Deployment With the proposed architecture, third party VASPs of RCSPP have the ability to offer their VAS in the form of downloadable applications. A VAS cannot be made available to mobile users before it is registered with the VAS provision platform by the corresponding VASP [3]. This is accomplished through a Web-like open API provided by the RCSPP to the authorised VASPs that facilitates and automates service deployment making it transparent to the VASPs. Through the aforementioned open API third party VASPs are provided with the ability to register new VAS with the platform, as well as to delete and update existing VAS. The RCSPM then performs all re-configuration actions that are necessary to accommodate the new or updated VAS. These actions comprise the storage of the service data in the Service DB and the configuration/reconfiguration of the MDs for monitoring the IP traffic flows concerning access to the registered VAS. During the VAS registration process the requesting VASP provides the RCSPM with an XML document including all the required information for supporting provision of the VAS to the end users. The XML document includes the necessary service identification information (VAS name, VASP identifier), as well as data needed for discovering (category, keywords, language, valid location), accessing (available service versions, service client location, minimum terminal capabilities and QoS required) and managing (application server IP address and port(s), tariffs, pricing model) the VAS. The “Valid location” field in this XML document expresses the geographical area or coverage extent in which a VAS is offered. By including location information in the VAS records, the RCSPM becomes aware of the location characteristics of registered VAS. Hence, whenever a user requests the RCSPM for service discovery the RCSPM is able to match the location of the requesting user with the valid location area of the available VAS to provide him with a listing of only those VAS that are offered at his current location. Furthermore, implicit location information is included in the XML document as part of the location based charging service offering described later in the paper. More specifically, this information comprises a statement whether a VAS is offered through location based charging, along with the applicable pricing policies that are associated with the usage of that VAS from within Home Zones or out of them.
B. Location and Mobility aware Service Discovery and Provision Taking into consideration the huge range of services available to the mobile users of the forthcoming 3G and 4G networks and the competitive nature of the new era, the demand for providing mobile subscribers with an efficient and simple mechanism for personalised VAS discovery and provision is rapidly raising [3][4]. Hence, the RCSPP provides users with the ability to discover and choose the VAS they wish to access by requesting VAS listings through a personalized, webportal like user interface, offered by the service discovery client. The VAS listings are presented to the requesting users after filtering the Service DB records according to the applicable terminal device’s capabilities, the current user location and the applicable user preferences specified in the user profile [3][4]. The retrieval of the terminal capabilities, the user preferences and the user location by the RCSPP takes place through the open interfaces provided by the Basic Network Management Layer for accessing the associated network servers (e.g. the Location Server, and the HSS) of the underlying network infrastructure. Each VAS in the service discovery listings is associated with a short description and indicative tariffing information, so that the user may choose VAS based on reduced cost criteria. Following the service discovery phase the user is able to select the desired service client and to download it to his terminal. Additionally to the VAS discovery mechanism, which takes into consideration the location of the user, the User Profile information [5] should also be location sensitive. By discriminating user preferences according to the location (e.g., Home, office, vacation) of the user and the time of the day and by maintaining different user profiles for each instance (e.g., Home-, office-, vacationdependent Profiles), better personalisation and customisation can be achieved during the service provision [4]. To this end, each subscriber upon registration with the RCSPP specifies his favorites Location-specific Zones (known as Home Zones) along with the applicable user preferences for VAS usage from within them. In such a case the service discovery function takes into account only the profile that better applies to the current location and status of the user, customising the VAS filtering and provision accordingly. During service access, the RCSPP tracks the location of the user in order to perform the required reconfiguration actions induced by the mobility of the user. Hence, upon entrance in or exit from a Home Zone an appropriate notification is sent to the user, notifying him for the new Home Zone or radio environment he entered, the new local VAS offered and the applicable pricing rates in there. At the same time, the applicable user preferences in the new Home Zone are retrieved from the HSS in order for the RCSPP to tailor the service offering accordingly. While the VAS is executed VASDRs from MDs and CDRs from UMTS network nodes (e.g. the CGF) are forwarded to the CAB so that the appropriate charges are included in the user bill.
C. Location and Mobility based Charging Location and Mobility based charging [8] is a flexible, location and mobility aware, charging model that takes location information by the network to provide subscribers with a personalised and customised charging/billing scheme. More specifically, with mobility and location based charging the RCSPP provider enables subscribers to define their own Home Zones according to the procedure described in the preceding section. Location information is then compared against Home Zones established for the users, so that subscribers are charged, for example, the same low “Home Zone” flat rate when they use their mobiles within Home areas. Outside Home Zones they will be billed at a higher rate, while different tariffs may be applied in different zones based on the time of day or week [8]. As subscribers move or cross predefined charging zones, or the applicable rate changes, it is required subscribers to be notified of their locationbased charging service offering indicating either "in" or "out" of zone, while a session is in progress or prior to its initiation. Information relevant to the location based charging offering of each VAS is included into the XML document describing a VAS. The user preference related to the location based charging activation/deactivation is included into the user profile [5]. Hence, in case that the location based charging feature has been enabled by a user into his user profile, the RCSPM shall apply this advanced charging scheme onto all activated sessions by the user that concern the usage of VAS. Furthermore, location based charging may be invoked upon initial registration with a VAS, while subscribers shall be able to activate/deactivate this feature by using specific feature’s codes of their VAS subscription profiles kept in their user profile. The Location and mobility based charging service is offered to VAS and other authorised entities through the open API provided by the Location Manager of the RCSPM (implemented by the activateLocationBasedChargingReq() and the cancelLocationBasedChargingReq() methods). The Message Sequence Chart (MSC) in Figure 2 (derived from the simulations that have been performed following the SDL specification of the RCSPP functionality) depicts the required interactions among components of the proposed architecture in case that Location based charging activation has been requested to the Location Manager of the RCSPM. More specifically: 1. Upon invocation by an authorised entity (e.g. an internal module of the RCSPM, or a VAS) of the ActivateLocationBasedChargingReq method the Location Manager of the RCSPM sends an appropriate notification to the specified user asking his confirmation for enabling location based charging and tracking his location. 2. On positive response the Location Manager retrieves the current location of the user in order to identify the originating Home Zone of the user.
3.
Then, the Location Manager invokes to the LCS server of the network a Mobile Terminated Deferred and Periodic Location Request [1] specifying as response event the crossing of the applicable Home Zones by the targeting User Equipment (UE). This information enables RCSPM to track the charging zones that the user visits while location based charging offering is enabled.
uses these records to charge the subscriber for the VAS usage in the associated Home Zone. In case that per user activation of the location based charging has been requested, the RCSPM at first requests the CAB to find out the VAS that the specified user currently executes (by invoking the directCollectIPFlowiInfoReq method offered by the CAB) and then instructs the MDs to close and send to the CAB the associated VASDRs. 5. The RCSPM notifies the subscriber about the new applicable pricing rates for the active VAS in his current geographical Zone. 6. Steps 4, 5 are repeated until the authorised entity that activated the Location based charging feature on step 1 invokes the CancelLocationBasedChargingReq method. When it happens the Location Manager interacts with the LCS server of the network to cancel [1] the Mobile Terminated Deferred and Periodic Location Request invoked on step 3. IV. Conclusions This paper presented the general architecture and the functional entities for location information management and exploitation of an advanced, open, flexible service provision platform for reconfigurable networks. The open APIs offered by the proposed architecture as well as the implementation details and the interactions required to accomplish location and mobility aware service deployment, service discovery and charging/billing were also discussed. REFERENCES
Figure 2. Interactions regarding Location and mobility based charging/billing 4. Following the notification by the LCS Server that the requested UE has entered into a new Home Zone or has gone out of them, the RCSPM instructs the MD (calling the directCollectMeteringDataReq method) to close and send to the CAB the VASDRs that are associated with the specified user and concern the usage of VAS within the previous charging zone. The RCSPM incorporates into the aforementioned request the geographical area (Home Zone or not) that the requesting user currently exited, along with the cause that triggered this method call (e.g. “In Home Zone Billing” or “Out Home Zone Billing”) so that MD includes this information into the VASDRs that it generates. The MD Reconfiguration Manager maps this incoming method call to the appropriate COPSPR messages to stimulate MDs to close and send to the CAB the requested VASDRs. The CAB, in turn,
[1] 3GPP TS 23.271: “Functional stage 2 description of LCS”. [2] M. Koutsopoulou, N. Alonistioti, E. Gazis, A. Kaloxylos, “Adaptive Charging Accounting and Billing system for the support of advanced business models for VAS provision in 3G systems”, Invited paper at the PIMRC 2001, San Diego, USA. [3] S. Panagiotakis, N. Houssos, N. Alonistioti, "Integrated Generic Architecture for Flexible Service Provision to Mobile Users", Invited paper at the PIMRC 2001, San Diego, USA. [4] At. Alonistioti, S. Panagiotakis, N. Houssos, A. Kaloxylos, "Issues for the provision of Locationdependent services over 3G networks", Invited paper at the 3GIS 2001, Athens, Greece. [5] 3GPP 23.240: “3GPP Generic User ProfileArchitecture, stage 2”. [6] 3GPP TS 29.198: “Open Service Access (OSA); Application Programming Interface (API); Part 112”. [7] M. Grech, R. McKinney, S.Sharma, J. Stanaway, D. Varney, K. Vemuri, “Delivering seamless services in open networks using intelligent service mediation”, Bell Labs technical journal, July-September 2000. [8] 3GPP TS 22.071: “Location Services (LCS); Service description, Stage 1”.
