Patent Application
20070032235
The invention relates to a telecommunications system and method for supporting mobility of mobile telecommunications terminals in such a system..
The invention is based on a priority application, EP 05291697.0, which is hereby incorporated by reference.
The invention relates to a method for supporting mobility of at least one mobile telecommunications terminal in operative connection with a telecommunications network having a plurality of telecommunications resources accessible via a plurality of access networks and associated access technologies in operative connection with the telecommunications network, wherein the mobile telecommunications terminal is provided with information about access networks and access technologies available at least at its present geographic location for choosing an access to the telecommunications network via one of the respective access networks and associated access technologies in accordance with specifications of at least one telecommunications resource requested by the mobile telecommunications terminal, and wherein the information are provided independently of the access networks by means of a mobility service broker system in operative connection with a plurality of access networks.
Furthermore, the present invention relates to a telecommunications system, comprising:
Additionally, the invention relates to a mobility service broker system for use in a telecommunications system of the above-mentioned type.
In the following, the term “telecommunications resources” refers to a variety of network data and media services. A non-exhaustive enumeration would include internet telephony, messaging, conferencing, voice mail, search services, portable digital device operation and media playback, entertainment, games, etc. In order to be able to use services of this kind, a (mobile) user must access the telecommunications network comprising said resources via access networks which are operated by respective access network providers/operators on a commercial basis and which are associated with certain available access technologies (see below), e.g. in the form of interfaces or data protocols. The quality of service depends on parameters such as maximal packet delay, packet jitter, bandwidth etc.
In state-of-the-art telecommunications systems mobile telecommunications terminals (in the following also simply referred to as “terminals”) access a telecommunications network via radio access networks with mobility support and by means of suitable access technologies (providing access to e.g. WiFi, WIMAX, GMS, UMTS; incl. combined heterogeneous technologies, as e.g. Bluetooth at DSL) available in association with a given access network and/or a given access network operator (multiple fixed/mobile/private). Furthermore, the terminals can switch over to other base stations/access points, which allow alternative access to said given access network. This happens if the required connection quality parameters for an active connection to a given access network by means of a particular access technology cannot be satisfied by the old base station/access point (provided that a better suited base station/access point is available), e.g. when a bandwidth required for a given telecommunications resource, such as receiving a video data stream, is not available by means of the old base station/access point. Usually, such a handover decision is performed by the access network based on an evaluation of the access situation at the location of the terminal.
As an alternative to the aforementioned handover to a base station/access point of the same access network, a terminal could also handover to another (wireless or wire-line) access network using an alternative access technology—provided that the terminal is capable of using that alternative access technology, and that the alternative technology offers a better connection quality or is preferred in accordance with a given rule set comprised in the base station/access point and/or the terminal. This is also referred to as “heterogeneous access management”.
For specific connection parameters, there are known prior art approaches disclosing a functional element in the access network which provides the terminal with the required information. Due to commercial reasons and to the disadvantage of the user, this solution as well as other known network based solutions addressing the heterogeneous access management issue will obviously be restricted to the offer of a choice between alternative access networks and associated access technologies provided by the same operator (or by a group of commercially linked operators) as said functional element is part of the access network owned by said operator. On the contrary, for pricing reasons the user argues for an access via a plurality of competitive operators as well as via proprietary networks.
Besides this, concepts are known which describe multi radio technology terminals wherein the terminal itself autonomously scans the availability of radio access networks using built-in radio technologies and uses this self-explored alternative access network information to switch over to an alternative network if connection quality parameters of the active connection fall below the requirements for this type of connection, e.g. bandwidth or quality of service. This approach suffers from the inherent lack of respective mechanisms for providing information about the full range of the different radio access networks and technologies available at the actual location of the mobile telecommunications terminal and for subsequently choosing one of the available access networks and/or access technologies. However, such mechanisms would be important in order to achieve the required connection quality parameters in an actual situation, which is changing dynamically with respect to the actual location and actual telecommunications resources being used, etc., without continuously having to run computing and communication resource intensive mechanisms and decision procedures proprietary to the mobile telecommunications terminal. Particularly, mobile terminals' power consumption is a critical parameter, such that for instance scanning of potential communication channels and other such mechanisms and procedures have to be avoided.
It is the object of the invention to provide a method for supporting mobility of at least one mobile telecommunications terminal in operative connection with a telecommunications network having a plurality of telecommunications resources accessible via a plurality of access networks and associated access technologies in operative connection with the telecommunications network, which obviates the disadvantages of the above-mentioned prior art approaches, e.g. by avoiding that mobile telecommunications terminals continuously have to run proprietary computing and communication resource intensive mechanisms and decision procedures in order to find available access networks and technologies.
It is also an object of the invention to provide a telecommunications system of the above-mentioned type as well as a mobility service broker system for use in said telecommunications system which obviate the above-mentioned disadvantages of prior art systems, e.g. by avoiding that mobile terminals have to scan potential communication channels, thus limiting power consumption.
This object is achieved by means of a method for supporting mobility of at least one mobile telecommunications terminal in operative connection with a telecommunications network having a plurality of telecommunications resources accessible via a plurality of access networks and associated access technologies in operative connection with the telecommunications network, wherein the mobile telecommunications terminal is provided with information about access networks and access technologies available at least at its present geographic location for choosing an access to the telecommunications network via one of the respective access networks and associated access technologies in accordance with specifications of at least one telecommunications resource requested by the mobile telecommunications terminal, and wherein the information are provided independently of the access networks by means of a mobility service broker system in operative connection with a plurality of access networks.
The object is also achieved by means of a telecommunications system of the above-mentioned type in which the mobility service broker system is adapted to provide the mobile telecommunications terminal with information about access networks and access technologies available at least at a present geographic location of the latter for choosing an access to the telecommunications network via one of the respective access networks and associated access technologies in accordance with specifications of the requested telecommunications resource, and in that the mobility service broker system is adapted to provide the information independently of the access networks.
Furthermore, the object is achieved by means of a mobility service broker system for use in a telecommunications system of the above-mentioned type, which is adapted to provide the mobile telecommunications terminal with information about access networks and access technologies available at least at a present geographic location of the latter for choosing an access to the telecommunications network via one of the respective access networks and associated access technologies in accordance with specifications of the requested telecommunications resource, and in that the mobility service broker system is adapted to provide the information independently of the access networks.
Thus, the invention basically solves the above-mentioned tasks by introducing a network-based cross domain mobility service broker system, which is independent from any access operator and/or access technology. Said broker interfaces to the individual resource managing entities of the various access operators, which manage the available telecommunications resources, possibly of more than one access technology, each of said entities within the scope of one access network operator. The mobility service broker system further sets up an information database which has a full view over the access networks of all operators with which it maintains a commercial relation. This database may preferably include even very local, e.g. WLAN or Bluetooth based, access points. The interface between the mobility service broker system and the specific access managing entities is devised to be a generic one, performing an abstraction of parameters which are specific to a particular access technology.
In a preferred embodiment of the inventive method the information is provided to the mobile telecommunications terminal dynamically in accordance with an access request by the mobile telecommunications terminal. This enables an adaptation of active telecommunications service sessions to changing requirements, e.g. increased bandwidth: State-of-the-art session initialization protocols like SIP (Session Initiation Protocol; used e.g. in NGN/IMS/TISPAN networks) allow the change of session quality parameters during the lifetime of a connection (“REINVITE”, “UPGRADE”) which usually changes the required bandwidth and QoS (Quality-of-Service) parameters for the connections concerned. In this context, according to a further development of the inventive method, the information preferably comprises at least one of available network access operator, available network access technology, available communication bandwidth, and available quality of service. Changing the bandwidth and QoS requirements may subsequently require changing the network access, e.g. because the current access does not provide sufficient bandwidth, or the like. In this case the mobility service broker system first evaluates the availability of access networks being able to serve the required bandwidth resource—said available access networks being “under selection”—and actively checks the appropriate quality parameters at the location of the terminal. To this end, the mobility service broker system advantageously sends out dynamic request messages to all of the available access networks, preferably upon reception of a corresponding access and/or service request from the mobile telecommunications terminal, i.e. essentially in real time.
In contrast to the scenario described above, which is based on real time dynamic requests for the demanded access networks and telecommunications resources issued by the mobility service broker system, an alternative approach consists in estimating the current access parameters based on non-real time information comprised in the mobility service broker system. In a further development of the inventive method, the information is therefore provided in accordance with non-real time information comprised in the mobility service broker system.
In order to further enhance mobility support of mobile terminals, hereinafter also referred to as “subscribers”, the mobility service broker system can be adapted to perform a prediction of the subscriber's motion direction and the availability of the access networks under selection for a given telecommunication service during a fraction of time, e.g. up to several minutes. According to a corresponding variant of the inventive method, the latter further comprises the steps of: the mobility service broker system performing a prediction of motion of the mobile telecommunications terminal; and the mobility service broker system proposing at least one suitable access network to the mobile telecommunications terminal in accordance with the predicted motion of the mobile telecommunications terminal. Taking into account said information with respect to the motion of the mobile telecommunications terminal, the mobility service broker system proposes the best suited known access network (as found in a static or dynamic map, see below) to the terminal for selecting an access network.
According to a another preferred embodiment of the inventive method, the mobility service broker system proposes at least one access network to the mobile telecommunications terminal in accordance with a prediction of motion of the mobile telecommunications terminal, wherein the prediction is obtained by means of a global map comprised in the mobility service broker system, in particular a digital road map. In this way an additional improvement of the motion prediction can be achieved, since the fastest movements of a typical subscriber are normally achieved on public roads, i.e. a mobile telecommunications terminal carried on board a car. In this context, the term “global” refers to a situation in which the mobility service broker system itself is in (static) possession of all the data necessary to map and predict the motion of the mobile telecommunications terminal, i.e. by means of pre-configured information.
Additionally or alternatively to using said pre-configured information, the mobility service broker system can gather signal strength measurement results received at earlier times from the same or other subscribers from different locations, e.g. different road positions, and categorize route segments with equal signal quality. In terms of the inventive method, the mobility service broker system therefore proposes at least one access network to the mobile telecommunications terminal in accordance with a prediction of motion of the mobile telecommunications terminal, the method further comprising the steps of: the mobility service broker system gathering communication signal quality measurements from the mobile telecommunications terminal and/or other mobile telecommunications terminals in relation with a present motion of the mobile telecommunications terminal; and categorizing areas on a global map comprd in the mobility service broker system, in particular route segments on a digital road map, according to the measured signal quality, said category information being used for proposing an access network. The size of the areas (route segments) depends on the signal quality variation. If the signal quality remains within the same category for several hundred meters, then the road segment size will be of the same order of magnitude.
This requires that—according to the invention—entities of the mobility service broker system, which are related to different subscribers, exchange quality records to generate said global maps. In other words: Signal quality information related to different mobile telecommunications terminals are exchanged within the mobility service broker system to generate a global map owned by the mobility service broker system for predicting motion of the mobile telecommunications terminal and for proposing at least one access network to the mobile telecommunications terminal in accordance with the predicted motion of the mobile telecommunications terminal. The information exchange is preferably carried out in an anonymized way, i.e. without revealing the identity of a given subscriber to the mobility service broker system. As more and more mobile terminals will be equipped with built-in GPS based localization systems, the exact location information of these systems can be used to further enhance the delivery of precise data tupels (position, signal strength, access network, provider, . . . ) to the mobility service broker system.
As an alternative to the above-described approach, which relies on the presence of a global map owned by the mobility service broker system, the latter can dynamically collect fragments of said signal quality information from operator specific databases, which are linked to intra-domain mobility management, or from third party databases. Correspondingly, in another variant of the inventive method signal quality information related to different mobile telecommunications terminals are gathered from access network operator owned and/or third party databases by the mobility service broker system to dynamically predict motion of the mobile telecommunications terminal and for proposing at least one access network to the mobile telecommunications terminal in accordance with the predicted motion of the mobile telecommunications terminal.
Advantageously, according to a further development of the inventive method a handover of the mobile telecommunications terminal between different access networks is supported by delivering information related to the mobile telecommunications terminal to an access network available at a future location of the mobile telecommunications terminal. In this way a fast and smooth handover of the subscriber to said access network is possible. In order to ensure seamless connectivity, a proactive handover can also be realized in consistency with the present invention (“make before break” across access network domains).
In order to limit power consumption of the mobile telecommunications terminal, the inventive method optimizes the radio access across operator domains by enabling the terminal to perform a handover to another provider and/or radio access technology which offer a required service quality at lower power consumption on the subscriber side by further comprising the step of changing to a different access network and/or access technology for access of the mobile telecommunications terminal to the telecommunications network if the respective access network or access technology offers a service quality required by the mobile telecommunications terminal at lower power consumption than a respective current access network or access technology. To this end, the information provided by the mobility service broker system can include a list of proposed access options based on current situation and service requirements.
In order to optimize the inventive method and the inventive telecommunications system with respect to subscriber costs, the mobility service broker system assures that a currently used service is always transported via the cheapest available access technology. In terms of the inventive method and in a preferred development, the method therefore comprises the step of changing to a different access network and/or access technology for access of the mobile telecommunications terminal to the telecommunications network if the respective access network or access technology offers a service required by the mobile telecommunications terminal at a lower cost. At times when the subscriber does not use any service, the mobility service broker system enables the terminal to automatically switch over to the cheapest available access network and/or technology. As soon as an subsequent incoming connection or the subscriber itself request a connection which requires a higher service quality than the one that is currently being used, the mobility service broker system initiates a handover to an appropriate access network and/or technology prior to establishing said connection. Correspondingly, a variant of the inventive method further comprises the step of changing to a different access network and/or access technology for access of the mobile telecommunications terminal to the telecommunications network if the respective current access network or access technology cannot offer a service or a service quality required by the mobile telecommunications terminal.
Furthermore, the mobility service broker system can be authorized to negotiate and organize payment (based on rules reflecting preferences of the individual subscriber). Particular business scenarios based on dynamic access costs can be supported by this kind of broker concept. The principles described above can be extended to multi-homed solutions, taking benefit from multiple access links which are active at the same time.
The present invention generally provides increased benefit for the end user of the terminal as the latter is always connected in an optimum way in terms of defined priorities such as power saving, service cost, bandwidth/QoS, etc. In order to achieve this, the inventive concept counts on the existence of a customer authorized operator independent broker system, i.e. in the form of said network based broker entities, having standardized interfaces to control entities of the individual access networks. By this means, an access selection and an operator selection, respectively, can be performed while taking into account the specific needs of the customer/subscriber. Furthermore, the subscriber is constantly informed with respect to the availability of network and/or technology accesses, which could not be discovered by the terminal itself, either due to technical limitations or for avoiding network scanning (in order to save energy and to stay continuously connected for incoming data).
Further advantages and characteristics of the present invention can be gathered from the following description of preferred embodiments with reference to the enclosed drawings. The features mentioned above as well as below can be used in accordance with the invention either individually or in conjunction. The embodiments mentioned are not to be understood as an exhaustive enumeration but rather as examples with regard to the underlying concept of the present invention.
Furthermore, the system 1 comprises a number of mobile telecommunications terminals 5.1-5.3 (“terminals”), e.g. cellular phones, accessing the network 2 via one of the plurality of access networks 4.1-4.3 and a specific associated access technology 4.1a,b-4.3a,b for requesting and subsequently using a service provided by at least one of the resources 3.1-3.6. Each of the terminals 5.1-5.3 comprises a decision unit 5.1a-5.3a for choosing between a plurality of available access networks 4.1-4.3 and/or a plurality of available access technologies 4.1a,b-4.3a,b, as will be explained in more detail below.
However, in accordance with the basic concept of the invention, the terminals do not communicate directly with one of the access networks 4.1-4.3. Instead, the system 1 comprises a mobility service broker system 6 (“broker”) in operative connection with the access networks 4.1-4.3, i.e. the terminals 5.1-5.3 indirectly communicate with the access networks 4.1-4.3 via the broker 6. It is an important feature of the present invention that the broker 6 be independent from the access network operators. In this way, a user sends a service request to the broker 6 by means of a terminal 5.1-5.3. The broker 6 then proposes one or several locally available access networks 4.1-4.3 and/or access technologies 4.1a,b-4.3a,b to the respective terminal 5.1-5.3, which meet certain service related communication requirements, e.g. bandwidth. The choice is then made by the respective decision unit 5.1a-5.3a based on a set of rules provided or approved by the terminal user.
To this end, with reference to
In order to improve mobility support, particularly at range limits, broker 6 (
In contrast to the above-described pre-configured information, the broker system can gather signal strength measurement results received earlier from the same or other subscribers, e.g. terminal 5.2 (“{circle around (x)}”) in
This feature of the inventive method can advantageously be used for ensuring smooth handovers by prematurely changing an access network and/or technology, e.g. switching from BA6 to BA7 already in segment SE2 or at the boundary of segments SE1 and SE2 instead of waiting until the boundary of segments SE2 and SE3 is reached and BA6 abruptly is no longer available. Such an early handover is also advantageous for reducing power consumption (traffic load) in the telecommunications terminal. Furthermore, the broker is capable of making a well-founded decision regarding the handover, since besides signal quality information, the direction of motion of the terminal can be taken into account, thus reducing the number of handovers. As stated before, base station BA7, i.e. the corresponding access network, will be informed by the broker prior to the actual handover.
Although in
In order to be able to generate said global digital maps gDM, broker entities 6.6a,b,c (
As an alternative to the above-described approach, which relies on the presence of a global map gDM owned by the broker, the latter can dynamically collect fragments of said signal quality information from operator specific databases, which are linked to intra-domain mobility management, or from third party databases. Correspondingly, the broker 6 (
In this way, it is possible to change to a different access network and/or access technology if the said different access network or access technology offers a service quality required by the mobile terminal at lower power consumption or at a lower cost than the current access network or access technology. Also, the present access network and/or access technology can be changed if the respective current access network or access technology cannot offer a service or a service quality required by the mobile terminal, e.g. due to a limitation of available bandwidth.
| Number | Date | Country | Kind |
|---|---|---|---|
| 05291697.0 | Aug 2005 | EP | regional |
