A communication system

Field of the Invention

0001The present invention relates to a communication system, and in particular, but not exclusively, to provision of information that associates with an equipment in communication via the system and/or with communication between at least two entities of the system.

Background of the Invention

0002Communication systems are known. A communication system enables communication between two or more entities such as user equipment and/or nodes implemented in the system. Communication systems typically operate in accordance with a given standard or specification which sets out what the various elements of the system are permitted to do and how that should be achieved. For example, the standard or specification may define if the user, or more precisely user equipment or terminal is provided with a circuit switched service and/or a packet switched service. Communication protocols and/or parameters which shall be used for the connection may also be defined. In other words, a specific set of "rules" on which the communication can be based on needs to be defined to enable communication in the system.

0003Communication systems providing wireless communication for the user terminals or other nodes are also known. An example of the wireless systems is a cellular network. In cellular systems, a base transceiver station (BTS) or similar serves mobile stations (MS·)· or similar wireless user equipment (UE) via an air or radio interface between these entities. A base station provides a radio access entity that is typically but not exclusively referred to as a cell. The operation of the base station apparatus and other apparatus required for the communication can be controlled by one or several control entities. The various control entities may be interconnected. One or more gateway nodes may also be provided for connecting the cellular network to other networks, e.g. to a public switched telephone network (PSTN) and other communication networks such as an IP (Internet Protocol) and/or other packet switched networks.

0004A cellular communication system may be adapted to provide packet switched (PS) services for a mobile stations. Example of-systems enabling packet switched services include the General Packet Radio Service (GPRS), the Enhanced Data rate for GSM Evolution (EDGE) mobile data network, the third generation (3G) telecommunication systems such as the Universal Mobile Telecommunication System (UMTS), i-phone or IMT-2000 (International Mobile Telecommunications) and the TErrestrial Trunked Radio (TETRA) system.

0005For example, in the current third generation (3G) architectures it is assumed that several different servers are used for handling functions required by various stages of processing of communication between two entities. These functions include different call state control functions (CSCFs) such as a proxy call state control function (P-CSCF), interrogating call state control function (I-CSCF), and serving call state control function (S-CSCF). Control f-unctions may also be provided by entities such as a home subscriber server (HSS) and various application servers.

0006From the above mentioned servers the home subscriber server HSS is for storing subscriber related information such as the registration identities (ID) of the subscriber or the terminals and so on. The home subscriber server HSS can be queried by other function entities during call or other session set-up procedures, e.g. for locating a subscriber. The term "session" refers to any communication such as to a call communication, data communication (e.g. web browsing) an so on.

0007However, the home subscriber server does not store dynamically any call related information or other information that relates to the status of a subscriber. In particular the current network systems are not provided with means for storing dynamically call related information or other information that relates to the status of a subscriber. For example, the home subscriber server HSS does not provide indication whether a subscriber is busy. Furthermore, e.g. in the packet switched environment a subscriber may have simultaneously one or more multimedia connections that are handled by different and from each other independent servers. The home subscriber server does not know if the subscriber is already having one or more of multimedia connections.

0008However, various network entities and/or services or other users may require information regarding the status of a certain subscriber or a call for their operation. An example of such a service/entity is the so called presence service/presence server.

0009In addition to "internal" clients, i.e. entities that are located within the network, the status information could be found useful by external clients. A client could be, for example, a user of a terminal or an entity that belongs to another network. For example, a user may want to know the status (e.g. availability) of another user (B-party). The user may find this information useful e.g. before trying to make a call to the B-party.

0010At present, for example in the GSM, the status of the B-pasty is checked over air interface. That is, a message is transmitted over the air interface to the B-subscriber mobile station. If the B-party mobile station receives the message it subsequently signals a response regarding the status thereof back to the network over the air interface.

0011A single network entity (e.g. the serving call state control function) may provide overall control for a connection. That is, the connection control can be "anchored" to and be provided by a serving network entity. This serving entity could be used to provide information that associates with a connection controlled by said entity. However, the inventors have found that this is not possible in the present network designs where the control functions of the multimedia or any other services may be distributed to be handled by different entities.

0012The inventors believe that services such as the presence service will become more popular among the users. Thus it must be assumed that the new services are generating a lot of new traffic into core network. The amount of traffic over the air interface generated by the new services may become substantially high and the possibility of overloading the air interface capacity may become a problem especially in the currently proposed 3G systems. Thus the inventors have found that an advantage could be provided if the status inquiry could be arranged to occur such that the inquiry is not transmitted over the air interface to the B-party mobile device as this wastes the limited air interface resources.

0013Another way of responding to these queries could ease the capacity problem. However, the inventors have found that the present network arrangements are not capable of providing the information that is required e.g. by the presence service in such a way that it could readily be accessed by an entity requiring the information- The prior art proposes no feasible solution for the storage and dynamic update of the status information and for the provision of this information for clients.

0014<patcit id="pcit0001" dnum="US5901352A"><text>US-A-5,901,352</text></patcit> discloses a system for enabling a network convergence and inter-working between multiple communication network. A subscriber is associated, with a plurality of communication networks each utilising its own schemes, protocols and standards for effectuating communication therein. A main centralised database stores subscription, network, service and location data associated with each of the communication networks.

0015<patcit id="pcit0002" dnum="WO9920065A"><text>WO-A-99/20065</text></patcit> discloses a method of providing information of the status of a call party in the mobile communication system-A new parameter is given which indicates the status of a mobile station as ready to receive a call.

0016<patcit id="pcit0003" dnum="US4313035A"><text>US-A-4,313,035</text></patcit> discloses a method for indicating status of a subscriber in a public switched telephone network.

Summary of the Invention

0017Embodiments of the present invention aim to address one or several of the above problems.

0018According to one aspect of the present invention, there is provided a communication, system comprising: communication means for providing communication media for a plurality of user equipment; a storage entity adapted to store information that is associated with at least one of said user equipment, wherein the storage entity is arranged to receive said information from other entities and to dynamically associate said received information with a respective user equipment; and at least one service provision entity adapted to serve a client based on said information stored in said storage entity, wherein said information comprises connection status information indicating the connection status of the user equipment.

0019According to another aspect of the present invention there is provided a server means for a communication system providing communication media for a plurality of user equipments, said server means comprising: interface means for receiving information associated with at least one of said user equipment adapted for communication via the communication system from at least one entity of the communication system; means for dynamically associating said received information with a respective user equipment; means for storing the information such that the information can be retrieved based on indication of a particular user equipment; and interface means for connection between the server means and at least one service entity, whereby the service entity is adapted to serve a client based on said information from the server means, wherein said information comprises connection status information indicating the connection status of the user equipment.

0020According to another aspect of the present invention there is provided a method in a communication system, said communication system providing communication media for a plurality of user equipment, the method comprising the steps of: generating information associated with at least one of said user equipment in an entity of the communication system; communicating said information to a storage entity; at the storage entity, receiving and dynamically associating said information with a respective user equipment; and providing said information that is associated with a respective user equipment to at least one service provision entity, whereby the service provision entity is enabled to serve a client based on said information from said storage entity, wherein said information comprises connection status information indicating the connection status of the user equipment.

0021The embodiments of the invention may provide an arrangement wherein the clients may readily be provided with information that associates e.g. with the status of a subscriber, communication session and/or an entity of the system. The provision of the information may be centralised in one entity that is functionally separated from those network entities that are required for the provision of communications in the system. The embodiments may also enable secure connections between the Information provision service and the clients. The embodiments may also enable arrangement where there is no need, to give an access for 3^rd parties to specific services and/or registries such as the home subscriber server or a location service. Thus the overall security may be improved. The embodiments may enable e.g. network operators to provide a set of better and richer services.

Brief Description of Drawings

0022For better understanding of the present invention, reference will now be made by way of example to the accompanying drawings in which: <ul id="ul0001" list-style="none" compact="compact"><li><figref idref="f0001">Figure 1</figref> shows a communication network architecture including a server entity in accordance with an embodiment of the present invention;</li><li><figref idref="f0002">Figures 2</figref> and <figref idref="f0003">3</figref> illustrate signalling between various entities of a communication system in accordance with a first and a second embodiment of the present invention; and</li><li><figref idref="f0004">Figure 4</figref> is a flowchart illustrating the operation of one embodiment of the present invention.</li></ul>

Description of Preferred Embodiments of the Invention

0023Reference is made to <figref idref="f0001">Figure 1</figref> which shows a possible network system architecture including a server entity 21 in accordance with an embodiment of the present invention. The exemplifying network system 10 is arranged in accordance with UMTS 3G specifications. The cellular communication system 10 is arranged such that the apparatus thereof is divided between a radio access network (RAN) 2 and a core network (CN) .

0024In general terms, a communication system can be described by a model in which the functions of the system are divided in several hierarchically arranged function layers. <figref idref="f0001">Figure 1</figref> shows three different function layers, i.e. a service layer, an application layer and a transport layer. The solid lines indicate actual data communication between various entities and networks. The dashed lines indicate signalling traffic between the network entities. The signalling is required for management and/or control functions of the network, such as for call session set-up, charging and so on.

0025It shall be appreciated that the layered model is shown only in order to illustrate the relationships between the various functions of a data communication system. In a physical i.e. real implementation the entities (e.g. servers or other nodes) are typically not arranged in a layered manner.

0026A plurality of user equipment 1 is served by a 3G radio access network (RAN) 2 over a wireless interface. Hence the user equipment will be referred to in the following by the term mobile station. The radio access network function is hierarchically located on the transport layer. It shall be appreciated that although <figref idref="f0001">Figure 1</figref> shows only one radio access network for clarity reasons, a typical communication network system comprises a number or radio access networks.

0027The 3G radio access network (RAN) 2 is shown to be physically connected to a serving general packet radio service support node (SGSN) entity 3. The SGSN 3 is a part of the core network. In the functional model the entity 3 belongs to the transport layer. The operation of a typical cellular network and the various transport level entities thereof is known by the skilled person and will thus not be explained in more detail herein.

0028An application layer 20 is shown to be located on top of the transport layer. The application layer 20 may include several application level functions. <figref idref="f0001">Figure 1</figref> shows two call state control entities (CSCFs) 22 and 23. From these the call state server 22 is a so called serving call state control function (S-CSCF). That is, the server 22 is currently serving at least one of the mobile stations 1 and is in control of the status of said at least one mobile station.

0029The application layer is also shown to comprise a home subscriber server (HSS) entity 24 and media gateway control function server entity 25. The home subscriber server HSS 24 is for storing the registration identities (ID) and similar information that relates to the users 1. The home subscriber server can be queried during a session set-up procedures.

0030In accordance with a preferred embodiment of the present invention the queries are served by a core network entity 21 that is adapted to centrally store the information in the core network. The following description will call this entity as a subscriber status server (SSS).

0031In <figref idref="f0001">Figure 1</figref> the subscriber status server (SSS) 21 is hierarchically located on the application layer 20. The subscriber status server 21 is adapted to store predefined call and/or subscriber related information. The information preferably includes status information. For example, the subscriber status server 21 may be adapted to dynamically store and provide an indication whether a user is busy or not. The information may be provided for any authorised client requesting for such information. More detailed examples of the-operation of the subscriber status server 21 will be discussed with reference to <figref idref="f0002">Figures 2</figref> and <figref idref="f0003">3</figref>.

0032In the preferred embodiment the subscriber status server entity 21 is adapted to dynamically store information associated with the status of the subscriber. That is, the status server 21 is connected to relevant network entities that provide the server 21 with information based on which the server 21 can provide status information for the clients. The information may be provided for the server 21 either via a direct connection between a network entity and the server or via one or more intermediate nodes. The information provision signalling may be based on any appropriate protocol. Preferably a protocols used by the network entity for communication with at least one other entity is used for the communication with the server 21.

0033The subscriber status server may receive information from various sources. For example, in <figref idref="f0002">Figure 2</figref> the status server is shown to receive information from two call state control function entities 22 and 23. The serving call state control function S-CSCF may provide information regarding the call state, e.g. whether the caller is busy or available.

0034The subscriber status server could also receive information related to other activities the user may have. That is, the information does not need to relate to communication sessions the subscriber is involved with. As an example, a subscriber status server may be provided with information that a user is having streaming video connection. This kind of information may be provided e.g. by one of the operator's servers.

0035<figref idref="f0003">Figure 3</figref> shows an embodiment where a home subscriber server 24 HSS provided the subscriber status server 21 with information. The HSS information may e.g. indicate whether a certain subscriber is on-line or off-line. The home subscriber server HSS 24 may also provide information regarding the aliases used by the subscriber and so on.

0036<figref idref="f0003">Figure 3</figref> shows also a gateway mobile location centre GMLC 26 of a location service (LCS). The location service may provide information regarding the geographical location of the mobile station. The skilled person is familiar with the location service and it will thus not be explained in any great detail herein. It is sufficient to note that the location service is a service that is arranged to provide geographical location information regarding a mobile station. The modern communication systems are capable of providing a location services. The data based on which the location information is generated may be measured by one of more of elements (not shown) that can be considered to be a part of the communication system or by external sources such as the known GPS (Global Positioning System).

0037The information is preferably signalled from the various entities towards the status server 21 without any specific information requests by the status server. For example, the serving call state control function 22 may be adapted to signal a message to the status server 21 whenever the status of a mobile station under its control changes.

0038It is also possible that the status server 21 periodically generates and transmits an inquiry for information. This may be signalled to all predefined entities or only to selected entities. The inquiry may regard a specific mobile station. The inquiry may also be a more general request for information regarding all mobile stations that are currently controlled by a specific entity.

0039Instead of or in addition to the periodic check the status server 21 may also transmit an inquiry to one or more entities in response to an information request from a client.

0040The subscriber status server 21 may thus receive information from various sources. The server is provided with appropriate processor means 32 so that it may process the information in order to associate the received information with respective mobile stations.

0041The information may be stored in appropriate memory means 33. The memory means may operate based on any appropriate arrangement, such as a database, a table, a record, a directory, and so on. The skilled person is familiar with possible means for the provision of the storage function, and these will thus not be described in more detail.

0042The identification of the mobile stations for the association may be based on, for example, the international mobile subscriber identity (IMSI) code, mobile subscriber integrated digital services number (MSISDN) code or temporary IMSI (TIMSI) code. New type of identifiers consisting of a data network address such as a public address in a SIP URL (Session Initiation Protocol Uniform Resource Locator) or a NAI URL (network access identifier URL) may also be used. An example of the first mentioned is <i>'sip:user@multimedia_operator.com'.</i> The latter could be, for example '<i>user</i>@<i>domain</i>'.

0043The subscriber status server 21 may offer the information to one ore more clients. For example, the information may be provided to any operator hosted session initiation protocol (SIP) application network element. The client may be a server such as a presence server (PS) 28 or a rich call server 29 or any other element of the communication system that may find the status information useful.

0044The information may also be provided to a client such a subscriber. The subscriber may, for example, wish to receive a status of another subscriber. The information may be useful e.g. when making a decision whether to try to make a call to the other subscriber. The subscriber may also wish to receive information regarding the status and location of another subscriber from one source.

0045It is also possible to arrange the location services to operate such that instead of querying the location service node 26, the subscriber may request location information from the subscriber status server 21 or from the presence server 28. Some operators or subscribers may find this type of operation useful e.g. due to security and/or usability reasons.

0046The information may be provided on request by the client. Alternatively, the status server 21 may provide the information periodically e.g. based on a timer function 31 implemented in the server. The information may also be provided in response to an event. For example, the information provision may be triggered by a message from the call state control function 22 indicative of a change in the status of a specified user equipment.

0047The signalling between the subscriber status server 21 and clients may be based on a protocol or protocols that are already used by the clients. For example, without limiting to these, the information may be signalled based on protocols such as the SIP, LDAP (lightweight directory access protocol), HTTP/XML or HTTP/HTML and so on. Signalling with clients such as the mobile station 1 is advantageously but not necessarily based on a protocol the mobile station is already adapted to use. A protocol that has been designed especially for the presence service may also be employed for the signalling.

0048<figref idref="f0002">Figure 2</figref> illustrates signalling for two exemplifying scenarios in which the information provided by the status server 21 can be useful. These scenarios are explained for a situation where mobile stations MS1 and MS2 are already having an established communication connection via appropriate network elements. This communication connection is indicated by the two headed arrow 30 between the stations MS1 and MS2. The communication is controlled by call state control function 22.

0049In the first scenario a mobile station MS3 intends to make a call to the mobile station MS2. The control entity 22 has informed the status server 21 of the existing call between the stations MS1 and MS2. Before the controller entity 23 continues further with the call set-up signalling to establish a call between stations MS3 and MS2, it sends an inquiry to the status server 21. The status server 21 responds with an indication that the station MS2 is busy. Based on this indication the control entity 23 may stop the call set-up procedure and signal an indication for the mobile station MS3 that the mobile station MS2 is busy.

0050In another scenario the user of a mobile station MS4 wants to receive information regarding the status of the mobile station MS2. The user transmits a request for the status information to a presence server entity 28. The presence server may then request for the information further from the status server 21.

0051As above, the control entity 22 has informed the status server 21 of the existing call between the stations MS1 and MS2. Thus the status server 21 responds with an indication that the station MS2 is busy. Based on this indication the presence server may signal an indication for the mobile station MS4 that the mobile station MS2 is busy.

0052The above operation is also illustrated by the flowchart of <figref idref="f0004">Figure 4</figref>.

0053The subscriber status server function entity may be integrated with a call state control function entity CSCF. Alternatively, as shown by <figref idref="f0002">Figure 2</figref>, the subscriber status server function may be located in a separate server entity 21. The separately located server may be provided with direct or indirect access to other entities, such as to the call state control function entity 22, home subscriber server 24, gateway mobile location centre (GMLC) 26, and application servers.

0054The operators may find the information provided by the status server 21 useful since it enables the communication network operators to offer e.g. better presence service than what the more conventional service providers (such as the internet search engine providers) are capable of offering.

0055The subscriber status server may be located behind a secure interface. The interface may be provided by a security server between the application requesting the status information and the subscriber status server. The subscriber status server itself may be adapted to offer a secure interface to trusted parties. The secure interfaces may be based on standardised secure interfaces.

0056The communication network system may be connected to several other networks, such as networks 4 to 6 of <figref idref="f0001">Figure 1</figref>. These connections may be provided by means of appropriate gateway nodes 7. The provision of these connections as such is not an essential part of the invention and will not be described in more detail herein.

0057The external networks may also communicate with function entities of the network 10 that are implemented on the layers on top of the transport layer. The communication signalling may occur either directly between an entity of the external network and an entity e.g. in the application layer or via an appropriate signaling gateway (SGW). Thus the application layer subscriber status server 21 may also serve entities that are a part of external communication systems or other clients that access the communication system via an external network.

0058The data to be communicated by means of an active connection may be so called packet data. In alternative embodiments of the invention the data may be sent in any suitable format. Correspondingly, the above referenced to packet switched systems but any other appropriate communication system may also be used. The embodiments are intended to run on top of a data communication system, such as a packet data system. Thus it shall be understood that the selection of the data communication system is not of essential as the data communication system is for the transport for e.g. multimedia (SIP protocol) signalling.

0059The embodiments may enable the operators to have better and richer service set e.g. an improved presence service. There is no need to give 3^rd party access to any other entities to the communication systems, such as the home subscriber server or the location service entities since the relevant information is stored in the subscriber status server. The subscriber status server may be assigned to have the sole responsibility for responding to any status enquiries.

0060The embodiments of the present invention has been described in the context of a 3G UMTS system. This invention is also applicable to any other standard where similar advantages may be obtained. For example, the embodiments are applicable for any system defined by the Internet Engineering Task Force (IETF) or any other standardisation body. The network system may also be, for example, based on a local area network (LAN), wireless LAN (WLAN ), a cable network, a xDSL based network, a GSM based system or any other network that is based on dial-up networking.

0061It should be appreciated that whilst embodiments of the present invention have been described in relation to mobile stations, embodiments of the present invention are applicable to any other suitable type of user equipment.

0062The above describes in detail a subscriber status server entity. However any entity in the network, such as the home subscriber server may be adapted to act as the subscriber status server.

0063It is also noted herein that while the above describes exemplifying embodiments of the invention, there are several variations and modifications which may be made to the disclosed solution without departing from the scope of the present invention as defined in the appended claims.