Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W76/00—Connection management
  • H04W76/20—Manipulation of established connections
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M2207/00—Type of exchange or network, i.e. telephonic medium, in which the telephonic communication takes place
  • H04M2207/18—Type of exchange or network, i.e. telephonic medium, in which the telephonic communication takes place wireless networks
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M3/00—Automatic or semi-automatic exchanges
  • H04M3/22—Arrangements for supervision, monitoring or testing
  • H04M3/2227—Quality of service monitoring
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M7/00—Arrangements for interconnection between switching centres
  • H04M7/006—Networks other than PSTN/ISDN providing telephone service, e.g. Voice over Internet Protocol (VoIP), including next generation networks with a packet-switched transport layer
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M7/00—Arrangements for interconnection between switching centres
  • H04M7/12—Arrangements for interconnection between switching centres for working between exchanges having different types of switching equipment, e.g. power-driven and step by step or decimal and non-decimal
  • H04M7/1205—Arrangements for interconnection between switching centres for working between exchanges having different types of switching equipment, e.g. power-driven and step by step or decimal and non-decimal where the types of switching equipement comprises PSTN/ISDN equipment and switching equipment of networks other than PSTN/ISDN, e.g. Internet Protocol networks
  • H04M7/1225—Details of core network interconnection arrangements
  • H04M7/123—Details of core network interconnection arrangements where the packet-switched network is an Internet Protocol Multimedia System-type network

Definitions

• the invention relates to a method for switching between two telephony services, for example a video telephony service and a voice telephony service.
• a cellular telephone system for example the third generation UMTS network
• the radio coverage area of the UMTS access network is divided into a plurality of cells, each provided with its own "NodeB" (node B) provided with 'a transceiver and intended to communicate with the mobile terminals located in its cell.
• nodeB node B
• the network detects the moment from which the transmission signal between the terminal and the "NodeB" to which it is connected is weakened and finds another available "NodeB” so to change the cell terminal.
• the terminal changes the "NodeB" to which it is connected while maintaining the communication in progress, without interrupting it.
• This inter-cellular transfer mechanism is commonly called the "handover".
• a mobile at each point of the territory must receive signals from at least two "NodeB” in order to be able to change cells (to a cell for which the received signal has better quality) .
• Third generation cell phone systems including UMTS
• the first solution is based on the "multicall" service, defined in Release 99 of UMTS. This functionality allows a user to establish and maintain two parallel telephone calls simultaneously through circuit switched sections of the third generation cellular telephone network. A mobile terminal with the "multicall” service can thus establish parallel video and voice communication simultaneously. It is planned to use the "multicall" service to implement the switching service previously mentioned:
• the terminal can make a call by the voice telephony service to the terminal with which it previously communicated in video mode. After establishing voice communication, video communication can be released.
• This solution has various drawbacks.
• the first drawback results from the fact that voice communication requires a certain establishment time, perceptible by the user, during which video communication, maintained in parallel, is degraded. During the delay in establishing voice communication, the quality of the communication may therefore not be satisfactory from the point of view of the user.
• the second drawback is linked to the fact that this solution can only be implemented between terminals supporting and having the "multicall" service.
• this service is not defined for the terminals of the fixed telephone network.
• this service is not yet currently supported by the mobile terminals offered to users and does not appear in the forecasts of the manufacturers of mobile terminals either.
• a third drawback lies in the fact that the implementation of the "multicall" service requires an adaptation of the MSCs (switches of the mobile service) of the core network of the UMTS system, which is not yet provided by the manufacturers.
• the second solution is based on the "service change", defined in Release 5 of UMTS.
• This service makes it possible, during a telephone call between two terminals, to switch from video mode to voice mode, and vice versa, insofar as the characteristics of the two communication modes were specified during the establishment of the call and where they are supported by the two terminals. It is envisaged to use this service to implement the switching service previously mentioned as follows: When the telephone communication in video mode between two terminals deteriorates, one of the terminals can request that the communication be switched voice mode. This solution nevertheless has certain drawbacks. On the one hand, the implementation of the "service change" requires modifications in all the elements of the UMTS communication chain: mobile terminals, RNC (access network controllers) and MSC (switches in the mobile service). However, these modifications are not yet envisaged by the equipment manufacturers.
• a terminal with the "service change” offered by its operator will not be able to benefit from this service when it is roaming abroad, or "roaming”, if the partner operator of "roaming" has not adapted its network for the "change” service, or when it communicates with a terminal of another mobile operator, if this interconnection partner operator has not adapted its network for the "service change”.
• the "multicall" service and the “service change” are certainly defined in Release 99 and in Release 5 of UMTS respectively, but neither the mobile terminals nor the current infrastructure of the mobile network are adapted to be able to implement provides these services.
• the two solutions explained above for carrying out a switching service from the video telephony service to the voice telephony service aiming to avoid a total interruption of the communication between the two terminals during video communication due to a degradation of that therefore, cannot be made operational in the short term.
• the problem of the invention therefore consists in proposing an alternative to these two solutions, the implementation of which would require only limited modifications to the communication chain. It will be noted here that the invention originates from a switching problem between the video telephone service and the voice telephone service. However, the invention is not limited to this particular case but more generally applies to a switching problem between two telephony services.
• the invention relates to a method of switching from a first telephone service to a second telephone service, in which, two terminals communicating with each other by the first service through a network, the procedure is carried out. switching from the first to the second telephone service so that the two terminals continue to communicate with each other via the second telephone service, characterized in that, in order to switch from the first to the second telephone service, a transformer of telephony service - interrupts the communication using the first telephony service between the two terminals, - calls in parallel the two terminals by the second telephony service then - connects the two terminals by abutment of the two communications established between, on the one hand, the transformer and, on the other hand, the two terminals respectively, in order to establish communication between the two termi by the second telephone service.
• the invention therefore consists in voluntarily cutting off the communication by the first telephony service between the two terminals, in initiating two communications between a transformer and the two terminals respectively by the second telephony service, then in abutting these in order to link the two terminals so that they communicate with each other by the second telephone service.
• the implementation of this process requires only a few modifications of the communication chain. Indeed, it suffices to add a transformer, placed in call cutoff between the two terminals.
• the first telephone service is a video telephone service and the second service is a voice telephone service.
• the method of the invention makes it possible to pass from a video communication to a communication by voice between two terminals, for example when one of them moves and passes in an area not covered by the service of video telephony.
• the network routes this call to the transformer so as to establish a communication by the first telephone service between the calling terminal and the transformer, ii) on reception of the call from the calling terminal, the transformer calls the called terminal in order to '' establish a communication with it by the first telephony service, then connects the two terminals by abutting the two respective communications between the calling terminal and the transformer, on the one hand, and between the transformer and the called terminal, on the other hand, in order to establish communication by the first telephone service between the two terminals.
• the invention also relates to a telephone service transformer for a network comprising i) call interruption means intended to interrupt a communication using the first telephony service between two terminals, ii) call means arranged to call in parallel the two terminals in order to establish with them two respective communications by the second telephone service and iii) abutment means arranged to connect the two terminals by abutting the two communications between the transformer, on the one hand, and the two terminals respectively, on the other hand, in order to establish communication between them by the second telephone service.
• the invention finally relates to a call routing device characterized in that it comprises means for identifying the telephone service used for communication between two terminals during the establishment of the latter and switching means intended at direct the call sent by one of the terminals, the "calling terminal”, and intended for the other terminal, the "called terminal”, to a telephony service transformer previously defined, in the case where it is a predefined telephone service.
• FIG. 1 shows a schematic view of UMTS cells allowing voice telephony service on all their covers and video telephone service on only part of their covers
• FIG. 2A represents the elements of a communication chain of a cellular telephone system of FIG. 1, in the case of an outgoing call, according to a first alternative embodiment
• FIG. 2B represents the elements of a communication chain of a cellular telephone system of FIG.
• FIGS. 2A and 2B represent a third generation mobile telephony system, in this case UMTS (universal system for communication with mobiles), integrating a video telephony service, or "videophone", allowing users to communicate between them by video (ie voice and moving pictures) and a voice telephone service, allowing users to communicate with each other only by voice.
• UMTS universal system for communication with mobiles
• This system comprises, in a known manner, a plurality of "NodeB" (nodes B) 1, RNC (access network controllers) 2, MSC 3 (switches for the mobile service) and G-MSC 4 playing the role of gateways between the UMTS network and the external switched telephone network, which includes the ISDN network (Digital Service Integration Network) 9.
• NodeB 1 is provided with a transceiver ensuring radio coverage of a cell, which includes a central part C1 and a peripheral part C2 ( Figure 1).
• the video telephone service and the voice telephone service are operational in the central part C1 of the cell, while only the voice telephone service is operational in the peripheral part C2 of the cell.
• FIG. 1 nodes B
• RNC access network controllers
• MSC 3 switching for the mobile service
• G-MSC 4 playing the role of gateways between the UMTS network and the external switched telephone network, which includes the ISDN network (Digital Service Integration Network) 9.
• Each NodeB 1 is provided with a transceiver ensuring radio
• the system further comprises call routers 5 and telephone service transformers 6.
• each transformer 6 is connected to several call routers 5 and, conversely, each router 5 is connected to several transformers 6.
• each transformer could be connected to a single router.
• the number of call routers 5 and the number of transformers 6 depend on the importance of video telephony traffic, on the one hand, and on the call processing capacities of the equipment 5 and 6, on the other hand. From the outset, it will be noted that: - an "outgoing call” designates a call on the initiative of a mobile terminal (to another mobile terminal or a fixed terminal) and - an "incoming call” designates a call to a mobile terminal (on the initiative of another mobile terminal or a fixed terminal).
• the UMTS communication chain comprises, in order, with reference to FIG. 2A: the mobile terminal calling T1, a "NodeB" 1, an RNC 2, an MSC 3, a call router 5 and a transformer 6.
• the UMTS communication chain comprises, in order, with reference to FIG. 2B: a G-MSC 4, a call router 5 , a transformer 6, an MSC 3, an RNC 2, a "NodeB" 1 and the mobile terminal called T2.
• a call router 5 is a device intended to route, in other words route, to the transformer 6 the calls coming from a "calling" terminal intended for a "called” terminal, when they are calls using video phone service.
• a module 50 for identifying the nature of the call intended to determine the telephony service used for the identified call
• a routing module 51 intended to direct the call either to the transformer 6 or directly to the called terminal, depending on whether it is a call by the video telephony service or a call by another telephony service, for example by the voice telephony service.
• the identification module 50 is intended to identify the type of service used by each call from a calling terminal to a called terminal, when at least one of the two terminals is a mobile terminal of the UMTS network.
• the identification module 50 analyzes the content of the 'Other Rate Adaptation' and 'FNUR' fields, appearing in the description of the support capabilities ("ISDN Bearer Capability") contained in the IAM message ( Initial Address Message) transmitted by the MSC 3 to the called terminal on receipt of the call setup CC-Setup message from the calling mobile terminal and initiating the communication.
• the identification module 50 analyzes the content of the 'Other Rate Adaptation' and 'FNUR' fields, appearing in the description of the support capacities ("ISDN Bearer Capability") contained in the IAM (Initial Address Message) message transmitted by the ISDN network 9 to the G-MSC 5.
• the referral module 51 is intended to direct the call identified by the module 50 to the transformer 6, if it is a video telephony call, or directly to the called terminal, if not.
• the transformer 6 is intended to transform the telephony service used between two terminals during communication. In the mobile telephone system represented in FIGS.
• the transformer 6 comprises - a module 60 for receiving a call set-up message containing the calling number and the called number, a module 61 for detecting a degradation in the quality of the communication between two terminals, a call cut module 62 arranged to interrupt a video communication in progress between two terminals, a call module 63 arranged for call terminals, - an abutment module 64 arranged to connect two terminals by abutting two communications between the transformer 6, on the one hand, and the two terminals respectively, on the other hand. a memory 65 for storing the calling and called numbers.
• the reception module 60 is arranged to - receive a call set-up message containing the calling number and the called number, in this case an IAM (Initial Address Message) message, originating either from an MSC 3, in the in the case of an outgoing video call (FIG. 2A), that is to say from a G-MSC 4, in the case of an incoming video call (FIG. 2B), and transmitted via a call router 5, and extract the two numbers, calling and called, from the IAM message and save them in memory 65 by associating them with one another.
• the detection module 61 is arranged to detect a degradation in the quality of the video communication between two terminals, here by analysis of the H.263 video coding protocol frames which transport the packets of coded video data between the two terminals.
• the detection module 61 determines the moment from which the quality of the video communication between two terminals becomes insufficient to be able to be continued properly.
• the quality of the video communication can become unsatisfactory for example because one of the two terminals, mobile, moves and passes inside an area located on the periphery of a "NodeB" cell, in which the video phone service is not operational.
• the call interruption module 62 is arranged to interrupt a video communication in progress between two terminals, on command of the detection module 61, when the quality of the video commumcation becomes insufficient, and to signal to the two terminals that a communication using voice telephony service will be established.
• the call module 63 is arranged to make calls, on the one hand, during the establishment of a video call between two terminals respectively "calling" and “called” and, on the other hand, after interruption by the call cut-off module 62 of a video commumcation in progress between two terminals: -
• the router 5 routes the call to the transformer 6.
• the call module 62 is arranged to, on receipt of this video call, call the terminal called by the video telephony service by inserting the identity of the calling terminal, by cash his call number, in a caller identification field transmitted to the called terminal.
• the call module 63 is arranged to call the two terminals in parallel in order to establish with them two respective communications by the voice telephony service.
• the abutment module 64 is arranged for, after interruption of a video communication between two terminals and establishment of two voice communications between the transformer 6 and the two terminals respectively, to terminate the communication between the transformer 6 and one of the terminals and the communication between the transformer 6 and the other termmal, that is to say end to end these two communications, in order to put the two terminals in communication by the voice telephony service.
• the method of switching from the video telephone service to the voice telephone service, corresponding to the operation of the call routers 5 and of the transformer 6, will now be described.
• the MSC 3 sends an IAM message (E3) to the terminal T2.
• the call router 5 intercepts the IAM message and identifies that it is a video call (c (i.e.
• the transformer 6 receives the IAM message, extracts the calling and called numbers therefrom and stores them in memory by associating them with one another. Then, the transformer 6 calls on the one hand the terminal called T2 and on the other hand finalizes the establishment of the communication with the calling terminal Tl, in the following manner: To call the terminal T2, the transformer 6 transmits to it ci a new IAM message (E5) by inserting the identity of the calling terminal Tl, constituted here by the call number of Tl, in the identification field of the caller.
• E5 a new IAM message
• the call is routed from the calling terminal T1 to the terminal called T2, via the transformer 6, by means of two IAM messages originating respectively from the MSC 3 (E3) and from the transformer 6 (E5) and both containing the number of the calling terminal Tl in the caller identification field.
• the origin of the call received is the terminal calling T1 and not the transformer 6.
• an ACM (Address Complete Message) message from the ISDN User Part (E6) layer is transmitted from the terminal called T2 to the transformer 6.
• an ANM (Answer Message) message (E8) is transmitted to the transformer 6 and a video telephone communication is then established between the terminal T2 and the transformer 6.
• the process of establishing communication between the calling terminal Tl and the transformer 6 ends as follows:
• the message ACM (E6) indicating that the terminal called T2 has been alerted by a ring tone and is retransmitted to MSC 3 by transformer 6 _E6).
• This information is transmitted to the calling terminal T1 by the MSC 3 by means of a message.
• CC Alerting (E7).
• the message ANM (E8) indicating that the called terminal T2 has picked up is retransmitted to the MSC 3 by the transformer 6 C 38) and this information is transmitted to the calling terminal by the MSC 3 by means of a CC Connect message ( E9).
• the calling terminal Tl then sends to the MSC 3 a CC Connect Ack message (E10) to confirm the establishment of the communication.
• a video telephone communication between the calling terminal T1 and the transformer 6 is then established. After establishment of the two video communications between, on the one hand, the transformer 6 and, on the other hand, the two terminals T1 and T2 respectively, the transformer 6 abuts the two communications in order to put the two terminals T1 and T2 in contact by video phone service.
• the two terminals T1 and T2 are thus put into communication by the video telephone service, via the transformer 6. However, the intervention of the transformer 6 is visible neither by the calling terminal and nor by the called terminal. After connection, the terminals T1 and T2 communicate by the video telephone service.
• This number is used to route the IAM message from the G-MSC 5 to the recipient MSC 3 (E3 ').
• the IAM message is intercepted by a call router 5 which identifies that it is a video call by analyzing the content of the 'Other Rate Adaptation' and 'FNUR' fields.
• the router 5 then routes the call to the transformer 6 with which it is associated, by retransmitting to it the received IAM message (E4 ').
• the transformer 6 receives the IAM message, extracts the calling and called numbers therefrom and stores them in memory by associating them with one another. Then, it calls the mobile terminal called 72 and finalizes the establishment of the communication with the fixed terminal calling T1, as follows: To call the terminal T2, the transformer 6 transmits to the MSC 3 to which the terminal
• the call 72 is connected to a new IAM message (E5 ′) by inserting therein the identity of the calling terminal Tl, constituted here by its number, in the identification field of the caller.
• the call is routed to the called terminal 72, via the transformer 6, by means of two IAM messages originating respectively from the ISDN network 9 (E1 ') and from the transformer 6 (E5') and both containing the number of the calling terminal Tl in the caller identification field.
• the origin of the received call is indeed the calling terminal T1 and not the transformer 6.
• the call establishment process between the transformer 6 and the mobile terminal T2 is continues in a known manner: on receipt of the IAM message, the MSC 3 sends a CC-Setup message (E6 ') to the terminal 72 which, on receipt of this message, sends it a CC-Call Confirmed (ET) message.
• the UMTS network then allocates the necessary resources in the UTRAN, consisting of the NodeB 1 and the RNC 2 to which the terminal 72 is connected, by an assignment RAB procedure (E8 ′).
• a CC-Alerting message (E9 ') is sent to the MSC 3 and relayed by an ACM (Address Complete Message) message (E10') to the transformer 6.
• a message CC-Connect (El l ') is transmitted from terminal 72 to MSC 3 then relayed by an ANM (Answer Message) message (E12') indicating that called party 72 has picked up, sent by MSC 3 to transformer 6.
• a video telephone communication is then established between the terminal called 72 and the transformer 6.
• the process of establishing communication between the calling terminal Tl and the transformer 6 ends as follows: the transformer 6 retransmits to the calling terminal 77 of the ISDN fixed network 9 the ACM message (_E10 ') 5 coming from the terminal called T2 and indicating that the latter has been alerted to the call by ringing, then the ANM message JB12'), coming from the term called 72 and indicating that the termmal called 72 has dropped .
• the video communication between the transformer 6 and the term called T1 is then established.
• the transformer 6 After establishment of the two video communications between, on the one hand, the transformer 6 and, on the other hand, the two terminals T1 and T2 respectively, the transformer 6 connects the two communications in order to connect the two terminals Tl and 72 by the video telephone service.
• the intervention of the transformer 6 is visible neither by the calling terminal Tl, nor by the called terminal 72.
• Process for switching from the video telephone service to the voice telephone service During video communication between the two terminals T1 and 72, at least one of the two terminals belonging to the UMTS network (incoming or outgoing call), the transformer 6 analyzes the H.263 video coding protocol frames which transport coded video data packets transmitted between the two terminals 77 and 72. In the particular example of the description, the transformer 6 monitors the quality of the video communication, by regularly evaluating the number of missing or erroneous data packets.
• the transformer 6 detects the degradation of the quality of the video communication and then interrupts it by transmitting in parallel to each of the two terminals T1 and 72 a warning message, in this case a Userlnputlndication message of the H.245 negotiation protocol. , signaling that a voice communication will be established.
• a warning message in this case a Userlnputlndication message of the H.245 negotiation protocol. , signaling that a voice communication will be established.
• each terminal T1, T2 signals this information to its user, here by displaying a message on the terminal.
• each terminal T1, T2 could stop on the last image displayed for the duration of the interruption of the communication, or send a voice warning message.
• the transformer 6 calls in parallel the two terminals T1 and 72 by the voice telephony service, thus establishing a first voice communication with the terminal T1 and a second voice communication with the terminal 72 then connects the two terminals T1 and 72 by joining the two voice communications.
• a communication between the two terminals Tl and 72 is thus established via the transformer 6 by the voice telephony service.
• the two terminals T1 and 72 continue their communication by the voice telephony service.
• the function of routing video calls to the transformer 6 is integrated into the MSC 3 and the G-MSC 5 of the UMTS network, these devices thus playing the role of call routing device.
• the video call identification module integrated into the MSC 3, is arranged to analyze the content of the 'Other Rate Adaptation' and 'FNUR' fields, appearing in the description part of the support capabilities ("TE Bearer Capability") contained in the CC-Setup call establishment message from the calling terminal and initiating communication.
• the video call identification module integrated in the G-MSC 5 is designed to analyze the content of the 'Other Rate Adaptation' and 'FNUR' fields, shown in the description of the support capabilities ("ISDN Bearer Capability") contained in the IAM message from the ISDN network 9.
• the transformer 6 makes it possible to switch from the video telephony service to the telephony service by the voice.
• the invention could be applied to switching between two telephony services other than those described.

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• Engineering & Computer Science (AREA)
• Computer Networks & Wireless Communication (AREA)
• Signal Processing (AREA)
• Mobile Radio Communication Systems (AREA)
• Telephonic Communication Services (AREA)

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• 2004
  • 2004-06-01 FR FR0451079A patent/FR2871015A1/fr active Pending
• 2005
  • 2005-05-24 EP EP05772969A patent/EP1752013A1/de not_active Withdrawn
  • 2005-05-24 CN CNA2005800204760A patent/CN1973568A/zh active Pending
  • 2005-05-24 US US11/628,348 patent/US20070249357A1/en not_active Abandoned
  • 2005-05-24 JP JP2007514006A patent/JP2008501267A/ja not_active Abandoned
  • 2005-05-24 KR KR1020067027839A patent/KR20070026692A/ko not_active Application Discontinuation
  • 2005-05-24 WO PCT/FR2005/001277 patent/WO2005120115A1/fr active Application Filing

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