WO2001041464A1

WO2001041464A1 - A system and a method relating to microcellular telecommunication networks

Info

Publication number: WO2001041464A1
Application number: PCT/SE2000/002317
Authority: WO
Inventors: Staffan SJÖDIN
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 1999-12-01
Filing date: 2000-11-24
Publication date: 2001-06-07
Also published as: AU1908801A; SE9904347D0; SE9904347L; SE517354C2

Abstract

The present invention relates to a private microcellular telecommunications network comprising a number of network nodes (10, 20, 30, 40) serving as home location nodes and/or visited nodes for a number of cordless telephones. The network nodes comprise means for obtaining information about which is the home location node for a number of cordless telephones (A, B) such that when a calling party (A) wants to make an outgoing call to another cordless telephone, a called party (B), the node (10) serving the calling party comprises a functionality for sending an enquiry message (1) to the home location node (30) of the called party over a separate connection (25), e.g. an IP-network. The home location node (30) of the called party (B) comprises a functionality of sending a response message (2), e.g. over the IP-network (25), to the node (10) serving the calling party (A) containing service profile data of the called party (B). The invention also relates to a method of, in a private microcellular network, setting up a call from a node serving a calling party to another (called) party including the steps of sending an enquiry message to the home location node of the called party to obtain service profile data using signalling on a separate network and receiving a response message from the home location node of the called party containing service profile data.

Description

Title: A SYSTEM AND A METHOD RELATING TO MICROCELLULAR TELECOMMUNICATION NETWORKS

FIELD OF THE INVENTION The present invention relates to private microcellular telecommunication networks comprising a number of network nodes serving as home location nodes and/or visited nodes for a number of cordless telephones of the network. The invention also relates to a method of, in a private microcellular network, setting up a call from a node serving a calling party of the private network to a called party of the private network.

STATE OF THE ART

A microcellular network generally comprises a number of network nodes such as for example PBXres (Private Branch Exchanges) or mobility serving means, or particularly mobility servers, which also may include a functionality of serving as a PBX or communicating with a PBX. A microcellular communications network may be comprised in a Digital European Cordless Telephone system (DECT) . The DECT telephone system is for example described in ETSI Standard 301 175 (Radio Equipment and System: Digital Cordless European Telephone, Common Interface) . Each cordless telephone in a microcellular network has one of the network nodes as its home location containing data relating to the cordless telephone, such as the current location and authentication keys. A microcellular network thus comprises a number of network nodes into which users of cordless telephones can roam. For network nodes comprising mobility serving means, particularly so called mobility servers, as for example discussed in US patent applications 08/786,552 and 08/948,552, the contents of which herewith are incorporated herein by the reference thereto, include a feature called personal number. The service feature provides the user with the possibility to be reached from one single number independently of where the user actually is located. The feature thus consists in a number of different service profiles for at least a number of users. As an example such profiles may contain or relate to a list of different destinations to call at different locations where the user may be. An example may for example be, for a new call, a first call attempt should be directed to the cordless telephone, for example a DECT telephone, a second call attempt may relate to a cellular mobile telephone, such as for example a GSM telephone (or a cellular telephone of any other cellular communication system) and a third alternative may be a public switched telephone or a fixed telephone and finally, if there is no answer of any of the telephone terminals, the call could be routed to a voice mail box. Thus such a profile may contain different options. Examples on a profile may for example be in office, out of office, absent, at home etc.

However, in state of the art systems, a call from a cordless user is always setup or switched to the home location node of the called party. The home location node then calls the called party (the B-party) according to the current profile. This means that a single call actually at least results in two calls, one call from the calling party to the home node of the called party and a second call from the home node of the called party to the final destination. If the calling party is located in a visited node of the system, often a call also has to made from the calling partys current (visited) location, i.e. the node currently serving the calling party, over the home location node of the calling party. From the calling party home location node is then the call to the called party generated which means that there may be three different call setups instead of one.

If for example neither a calling party nor a called party are at their home location nodes, the procedure in state of the art system is as follows: A calling party makes of hook, a call is established between the node visited by the calling party and the home location node of a calling party. Then the calling party then dials the number of a party to be called; a new call is setup from the home location node of the calling party to the home location node of the called party. Finally a call is setup from the home location node of the called party to the visited node of the called party. It is obvious that such a procedure is very disadvantageous and the number of switched connections are high and it is the home location of the called party that actually has to set up calls according to the service profile of the called party.

SUMMARY OF THE INVENTION What is needed is therefore a private microcellular telecommunication network as initially referred to wherein calls can be setup according to a service profile in an easy manner. Particularly a network is needed in which calls can be setup according to a service profile without requiring a plurality of switched speech connections or call setups. Particularly a network is needed through which the number of calls needed to reach a called party of the private network irrespectively of where the user actually is located can be reduced considerably as compared to in hitherto known networks. Particularly a private network is needed through which a call setup to a cordless telephone of the network from another cordless telephone of the network according to the service profile of the called telephone in such a manner that resources can be saved. Therefore also a method is needed for, in a private microcellular network, setup a call from a node serving a calling party to a called party of the private network through which the above mentioned objects can be met. Even more particularly a method is needed through which also the other objects referred to above can be met.

Therefore a private microcellular telecommunications network as initially referred to is provided wherein the network nodes comprise means obtaining and/or storing information about which is the home location for a number cordless telephones of the microcellular network. When a cordless telephone, also called a calling party, which currently is served by a network node, i.e. its home location node or a node that it currently visits, wants to make an outgoing call to another cordless telephone of the private microcellular network, also referred to as a called party, the node serving the calling party comprises a functionality for sending an enquiry message to the home location node of the called party over a separate connection, particularly an IP network, e.g. an intranet or Internet, and the node acting as a home location for the called party comprises a functionality of sending a response message, e.g. over the IP network, to the node serving the calling party, which response message at least contains service profile data of the called party. Advantageously the service profile of the called party is executed in the node currently serving the calling party, i.e. the serving node comprises means for setting up a call as according to the service profile of the called party. According to one implementation the functionality is included in the home location node of the calling party (A-party) , thus the home location node executes the service profile of the called party. In an alternative embodiment the calling party is in a visited node and the visited node comprises the functionality for obtaining and executing the service profile of the called party (also called the B-party) .

In a particular implementation the service profile data of a party contains information relating to setting up a call to the party according to a number of different alternatives. Particularly the service profile information data relating to call set up contains a list of destinations of where to switch an incoming call. Particularly the service profile contains a number of options such as e.g. one or more of private network cordless telephone, cellular telephone, fixed telephone, voice-mail box etc. e.g. relating to in office, within private network, out of office, absent. Thus the service profile contains a list of different alternatives and specifies the order in which the alternatives should be tried or under which circumstances. Preferably it also specifies when a particular alternative should be proceeded to; i.e. the time to wait for an answer etc.

In a particular implementation the node serving the calling party is able to set up a call directly to the relevant destination according to the service profile of the called party, e.g. using the private network to the node currently serving the called party if it is within the private network, using PSTN to a fixed telephone or via PSTN to a cellular communication system. Particularly, if the network node serving the calling party has no PSTN connection, the call is switched to a network node having a PSTN connection for a call to a fixed telephone or to a cellular telephone according to the service profile.

Particularly at least some of the nodes comprise a broadcasting functionality, and in order to obtain location information of a called party, a broadcast message is sent to all nodes with identity information about the called party, the home location node of the called party then sending a response message particularly including service profile data of the called party. Thus, this advantageous implementation is based on mobility management as discussed in the copending patent application "System and method relating to private telecommunication systems" filed on the same date and by the same applicant as the present application, the contents of which herewith is incorporated herein by reference. This thus means that no separate inquiry has to be sent out in order to obtain the profile data. In an alternative implementation location information is obtained according to the document referred to and still a separate inquiry message is sent out to the home location node of the called party to obtain the service profile of the called party. Alternatively home location information of the called party is stored in a table in the node in a conventional manner.

The network nodes, or some of them, may comprise PBX:es (Private Branch Exchanges). In an alternative implementation at least some of the network nodes comprise mobility serving means, e.g. mobility servers communicating with PBX:es or including a PBX functionality. Still further, at least some of the network nodes, particularly mobility servers, support a personal number functionality which support a service of enabling a user to be reached from single number irrespectively of where the user is located.

Therefore also a method as initially referred is provided which comprises the steps of; finding the home location node of the called party; sending an inquiry message to the home location node of the called party to obtain service profile data relating to the called party using signalling on a separate network; sending a response message containing service profile data of the called party from the home location node of the called party to the node serving the calling party over the separate network; executing the service profile of the called party in the node currently serving the calling party; setting up a call to the called party according to the service profile. Particularly the separate network used for signalling is an IP-network, e.g. an intranet or Internet.

In a particular implementation the method includes the step of; storing information on home location node for a number of cordless telephones and finding information about the called party in the storing means. Alternatively the method includes the steps of, looking up the home location node of a called party in a table in the node. In a particular implementation the invention comprises the step of, for finding the home location node of a called party, sending, via broadcast, an inquiry message to all nodes of the private network which message contains information relating to the identity of the called party; receiving a response message from the home location node of the called party containing both location information and service profile data in the node currently serving the calling party.

In an alternative implementation the method includes the steps of; a calling party dialling the number of a called party; analysing the number of the called party to establish if the dialled number relates to a cordless telephone of the private network, if yes; analysing if the node serving the calling party is the home location also of the called party, if yes; executing the call according the service profile of the called party, otherwise; sending an enquiry message to the home location node of the called party to obtain service profile data of the called party; setting up one of more calls according to the service profile once service profile data is received. Particularly the method includes the steps of; using the private network for a call setup within the private network directly to the node currently serving the called party if the call is to be made to the cordless telephone of the called party; setting up the call to an external PSTN connection if the call is to be made to a public, fixed or cellular, network.

It is an advantage of the invention that the number of switched speech connections are reduced to a minimum. Particularly it is an advantage that a call can be set up directly from the node serving a calling party and that said node is able to execute the service profile of the called party without having to set up calls also via intermediate nodes except when a call is to be set up to a cellular telephone or a fixed telephone etc. or to a cordless telephone of another private network.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will in the following be further described in a non- limiting manner and with reference to the accompanying drawings in which:

Fig. 1 schematically illustrates a microcellular network for which the inventive concept is implemented,

Fig. 2 is a figure similar to that of Fig. 1 exemplifying messaging and call connections for a given service profile,

Fig. 3 schematically illustrates the signalling relating to messages for carrying out the invention,

Fig. 4 is a flow diagram describing a call to a cordless telephone of the microcellular network, Fig. 5 is a flow diagram illustrating the home location node of a called party receiving a request for a profile data, and

Fig. 6 is a flow diagram describing an implementation of the inventive concept.

DETAILED DESCRIPTION OF THE INVENTION

Fig. 1 very schematically illustrates a microcellular network comprising network nodes NN 10,20,30,40. Two cordless telephones A, B are also illustrated. It is here supposed that NN 10 is a network node currently serving cordless telephone A, i.e. the network node serving the area that A currently visits. NN 20 is supposed to be the home location node of cordless telephone A. NN 30 is supposed to be the home location node of cordless telephone B whereas cordless telephone B currently visits NN 40. The network nodes may for example be PBX:es or mobility serving means, particularly mobility servers. A mobility server may also include the functionality of a PBX or it may be associated with a PBX, e.g. arranged between the PBX and a number of radio exchanges. According to one embodiment the private network 5 is used for calls within the private network. PSTN 15 is used for calls to a public network or a mobile cellular network (not shown) . Used for the signalling relating to request messages relating to service profile and response messages containing service profile data is an IP network 25, e.g. an intranet or Internet which uses TCP/IP, Transmission Control Protocol/Internet Protocol. Thus IP network 25 is at least used for signalling relating to requesting service profile data and sending of service profile data between the network nodes. In a particular embodiment as further discussed in the co-pending patent application "System and method relating to private telecommunication system" an IP network or a data communication network in general, e.g. ATM or Packet Frame Relay can also be used for providing distributed home location databases .

Furthermore, in a particular implementation, a public network for example using TLDN (Temporary Location Designation Number) as more thoroughly discussed in a patent application "A system, an arrangement and a method relating to interconnection of telecommunication network arrangement" which was filed on October 14, 1999 by the same applicant which is herewith incorporated herein by reference, or alternatively a private ISDN-Q is used for connection of calls etc. ISDN-Q is described in ECMA/143 "Basic Call" ECMA/165 "Generic functions", and ETSI EN 301 172 Ver. 1.4.1 and ETS 300 239, Second edition. In other networks DPNSS may be used which relates to the British Telecom Standard BTNR 188. This however merely relates to a particular embodiment. This application is applicable irrespectively of in which way calls are set up in other respects. It is also applicable irrespectively of how information about which is the home location node of a particular party is obtained. Thus, a microcellular network comprises a number of nodes NN 10-40 into the area of which users having a cordless telephone can roam in a particularly advantageous implementation relates to a case in which such nodes comprise mobility servers although the invention is not restricted thereto. A feature that is provided in a mobility server is the personal number which is a feature giving a user a possibility to be reached with one single number independently of where the user is located. This feature comprises a number of service profiles for each user. Mainly such profiles contain lists for different destinations to call in a given order under particular circumstances etc. One example on a service profile may for example be that for a new call a first call attempt is a cordless telephone of the private network, e.g. a DECT telephone, a second alternative may be a cellular telephone such as for example a GSM telephone, a third alternative may be a public telephone and if there is no answer on any of the terminals, the call can be routed to a voice-mail box. Such an example on a profile may for example relates to in office, out of office, at home, absent etc.

It is for example supposed that the A-party is located in the visited node NN 10 whereas NN 20 is the home location node of the A-party, the B-party is located in visited node NN 40, NN 30 being the home location node of the B-party. It is now supposed that the A-party wants to make a call to the B-party. In a particular embodiment this can be done through one single call and this is further discussed in the co-pending patent application "System and method relating to a private telecommunications system" using the IP network 25 for signalling. However, this merely relates to one advantageous embodiment of the invention the main thing being that the service profile of the B-party can be executed in the node visited by the A-party, NN 10 and thus a direct call to the node visited by the B-party, NN 20 can be done. Thus, according to the invention (cf. Fig. 2) when the A-party dials the number of the B- party, the visited node of the A-party, NN 10, sends an inquiry message to the home location node of the B-party, NN 30, requesting profile data of the B-party (1) . Profile data is then sent in a message from the home location node, NN 30, of the B- party to the visited node NN 10 of the A-party (2) the IP network 25. Execution of the service profile is then performed in the node visited by the A-party, NN 10. If the call should be made to the cordless telephone of the B-party, the call is set up directly to the B-party over the private network 5 (3a) .

If a call should be made to the public network, a call is set up directly to an external line in NN 10 to PSTN (3b) , or if NN 10 does not have any appropriate PSTN connection, this is done via another network node having a suitable PSTN connection (not shown in the figure) . It should be clear that this was merely one particular example of a service profile, a number of other alternatives are of course being possible. In all the cases however, the number of switched speech connections are reduced to a minimum.

Fig. 3 is a simple signalling diagram illustrating a request for a service profile (1) being sent from NN 10, the node visited by the A-party, to NN 30, being the home location node of the B-party. This means that, when NN 10 analyses the number dialed by the A- party, it establishes that the dialled number is a user with a home location in NN 30. The inquiry message of the profile request is then sent to NN 30 requesting information about a personal number profile. NN 30 then sends a profile response message (2) to NN 10 containing information about how the B-party can be located. NN 10 then executes the service function according to the received profile and it may for example set up a call to NN 40 which is the node visited by the B-party or alternatively a call may be set up to NN 40 which is visited by the B-party via NN 30 being the home location of the B-party and if no answer is received, the service profile is followed.

Fig. 4 illustrates in the form of a flow diagram the same procedure. I.e., first the A-party dials a number, 100. It is first established if the dialled number relates to a cordless telephone of the private network, 110. If not, a call is set up in a conventional manner, or whatever is done, 110A, this not being relevant for the functioning of the present invention. If however it was established that the dialled number relates to a cordless telephone, it is subsequently established if the node serving the calling party, i.e. NN 10, also is the home location node of the called party, 120. If yes, the call is executed according to the service profile of the B-party, 120A since the service profile data already is available in the node. If not, an enquiry message is sent to the home location node of the called party, i.e. of the B-party, 130, since it is supposed that the node currently serving the calling party in some way knows or has obtained information about which is the home location node of the called party. Then a response is awaited, illustrated through a dashed line in the flow diagram, and as such arrives, here a response message containing service profile data of the B-party, 140, it is analysed and executed in the node currently serving the A-party. Thus, one or more calls is/are set up in agreement with the service profile, 150.

Fig. 5 is a very schematical flow diagram describing the reception of a request message for the service profile of a called party in the home location node of said called party, i.e. the B-party, 200. The node being the home location of the B-party contains service profiles of not only the B-party but of all the cordless telephones having the node as its home location node (and actually having implemented the service profile feature or having a personal number, which may be optional) reads e.g. from a database, the current profile for the called party, the B-party, 210. Then the home location node of the B-party sends a response message to the enquiring node which may be the node a calling party visits or the node serving as a home location node for the calling party. The message that is sent contains the service profile data of the B-party, 220, and the response message is sent over an IP network. To find out the relevant data of the calling party, the PUN (Personal Unit Number) is particularly sent with the request such that the home location node of the B-party can recognize and find the relevant service profile data.

Fig. 6 is a flow diagram describing the whole procedure with one example on a service profile. Thus it is supposed that a profile request is sent from a node serving an A-party to the home location of a B-party, 300. It is thereupon supposed that the response message containing profile data is received in the node serving the A-party, 310, as already discussed above. The service profile data is then analysed in the node serving the A-party, 320. According to the particular service profile, a first call attempt is to be done to the node visited by the B-party. A call is then set up directly (or indirectly) to the node visited by the B-party, 330. An answer is awaited and if the answer arrives within a given time interval, for example 20 seconds, the call set up procedure proceeds in a conventional manner, 340. If the answer is not received within the predetermined time interval; the service profile says that a call is to be set up to a GSM mobile telephone which is done via PSTN, 350. Again an answer is awaited to see if it arrives within a given time interval which may be the same as above or another, for example 18 seconds, 360. If the B- user answers, a call set up proceeds in a conventional manner, if however there is no answer, the next alternative answer of the profile is here supposed to be that the voice mail box should be called. The voice mail box is located at the home location node of the B-party and preferably the voice mail box is called directly, 370. It should however be clear that this merely relates to one particular example on a service profile, that the different options etc. of the service profile are not relevant for the functioning of the present invention, it essentially being that the service profile actually can be executed in the node visited by a calling party and that a data communication network, particularly an IP network is used for the signalling. Instead of an IP network may e.g. a network implementing ATM (Assynchronous Transfer Mode) or Packet Frame Relay be used.

Also in other aspects the invention is not limited to the explicitely illustrated embodiment but it can be varied freely in a number of ways without departing from the scope of the appended claims .

Claims

1. A private cellular telecommunications network comprising a number of network nodes (10,20,30,40) serving as home location nodes and/or visited nodes for a number of cordless telephones (A,B), c h a r a c t e r i z e d i n that the network nodes comprise means for obtaining and/or storing information about which is the home location node for a number of cordless telephones such that when a cordless telephone, a calling party (A), currently served by a network node (10) wants to make an outgoing call to another cordless telephone, a called party (B) , of the private network, the node (10) serving the calling party comprises a functionality for sending an enquiry message to the home location node (30) of the called party (B) over a separate connection (25), e.g. an IP-network or another data communication network, and in that the node (30) acting as a home location for the called party comprises a functionality of sending a response message over the data communication network, e.g. over the IP-network (25), to the node (10) serving the calling party (A) at least containing service profile data of the called party.

2 . A network according to claim 1 , c h a r a c t e r i z e d i n that the service profile of the called party (B) is executed in the node (10) currently serving the calling party (A), which comprises means for interpreting and setting up calls according to the service profile.

3. A network according to claim 2, c h a r a c t e r i z e d i n that the node currently serving the calling party is the home location node of the calling party.

4. A network according to claim 2, c h a r a c t e r i z e d i n that the node currently serving the calling party (A) is a visited node (10), i.e. the node visited by the calling party.

5. A network according to any one of claims 2-4, c h a r a c t e r i z e d i n that the service profile of a party contains information relating to setting up a call to the party according to a number of different alternatives, in a given order or under given circumstances.

6. A network according to claim 5, c h a r a c t e r i z e d i n that the service profile information relating to call set up contains a list of destinations of where to switch an incoming call.

7. A network according to claim 5 or 6, c h a r a c t e r i z e d i n that the service profile contains a number of options such as e.g. one or more of private network cordless telephone, cellular telephone, fixed telephone, voice-mail box, e.g. relating to in office, within private network, out of office, absent.

8. A network according to claim 7, c h a r a c t e r i z e d i n that the node (10) serving the calling party (A) is able to set up a call directly to the relevant destination according to the service profile of the called party (B) , e.g. to the node (40) currently serving the called party using the private network, using PSTN to a fixed telephone or via PSTN to a cellular communication system.

9. A network according to claim 8, c h a r a c t e r i z e d i n that if the network node serving the calling party has no PSTN connection, the call is switched to a node having a PSTN connection for a call to a public telephone or to a cellular telephone .

10. A network according to any one of the preceding claims, c h a r a c t e r i z e d i n that the nodes comprise a broadcasting functionality and in order to obtain location information of a called party, a broadcast message is sent to all nodes with information about the called party, the home location node (30) of the called party recognizing it sending a response message including service profile data of the called party.

11. A network according to any one of claims 1-9, c h a r a c t e r i z e d i n that home location information relating to the called party is setched from storing means in the node in a conventional manner.

12. A network according to any one of the preceding claims, c h a r a c t e r i z e d i n that at least some of the network nodes comprise PBX:es.

13. A network according to any one of the preceding claims, c h a r a c t e r i z e d i n that at least one of the network nodes comprise mobility serving means (10,20,30,40), e.g. a mobility servers communicating with a PBX or including a PBX-functionality .

14. A network according to claim 12 or 13, c h a r a c t e r i z e d i n that at least some of the network nodes support a Personal Number feature supporting a service of enabling a user to be reached from a single number irrespectively of the location of the user.

15. A method of, in a private microcellular network, setting up a call from a node serving a calling party of the private network to a called party of the private network, c h a r a c t e r i z e d i n that it comprises the steps of: finding the home location node of the called party, sending an enquiry message to the home location node of the called party requesting service profile data relating to the called party using signalling on a separate network, - sending a response message containing service profile data of the called party from the home location node of the called party to the node serving the calling party over the separate network, executing the service profile of the called party in the node currently serving the calling party, setting up call(s) to the called party according to the service profile.

16. A method according to claim 15, c h a r a c t e r i z e d i n that the separate network in an IP-network, e.g. an intranet or Internet, or another data communication network.

17. A method according to claim 15 or 16, c h a r a c t e r i z e d i n that it includes the steps of: storing information on home location node for a number of cordless telephones in storing means, separate or in the respective nodes, and finding information about the called party in the storing means .

18. A method according to claim 15 or 16, c h a r a c t e r i z e d i n that it comprises the step of, for finding the home location node of a called party, performing a look-up in storing means in the node.

19. A method according to claim 15 or 16, c h a r a c t e r i z e d i n that it comprises the step of, for finding the home location node of a called party, - sending via broadcast, an enquiry message to all nodes of the private network containing information relating to identity of the called party, receiving a response message from the home location node of the called party containing both location information and service profile data.

20. A method according to any one of claims 15-18, c h a r a c t e r i z e d i n that it comprises the steps of: - a calling party dialling a number of a called party, analysing the number of the called party to establish if the dialed number relates to a cordless telephone of the private network, if yes, analysing if the node serving the calling party is the home location node of the called party; if yes, executing the call according to the service profile of the called party; otherwise, sending on enquiry message to the home location node of the called party to obtain service profile data of the called party, setting up one or more calls according to the service profile when service profile data is received.

21. A method according to any one of claims 16-21, c h a r a c t e r i z e d i n that it comprises the steps of: using the private network for call set up within the private network, directly to the node currently serving the called party if the call is to be mode to the cordless telephone of the called party, setting up the call to an external PSTN connection if the call is to be made to a public fixed or cellular network.