FR2743251A1 - SYSTEM AND METHOD FOR RADIO TELECOMMUNICATIONS WHICH ALLOW FOR A MANAGEMENT OF NOMADISM STRUCTURED IN LAYERS AND EXTENDING OVER A LARGE AREA - Google Patents

Abstract

A telecommunications system (10) includes a wide area transmission network (12) and any number of local transmission networks. The wide area transmission network (12) has any number of switching centers (18), and each local transmission network has at least one mobile switching center (28). Multimode subscriber units (20) can operate on either of these types of networks. Roaming management services are provided to mobile unit switching centers (28) receiving roaming contacts from nomadic subscriber units (20) through the wide area transmission network (12). For any local transmission network, roaming management services are provided through a single switching center (18), regardless of the switching center included within the transmission network over a wide area (12) which constitutes the home node for the nomadic subscriber unit (20).

Description

The present invention relates generally to the provision of services

  defects in nomadic management (that is to say movement of subscriber units outside their home centers) in radio telecommunications systems. Subscriber units used in connection with tele-

  radio communications are often recorded with a connection system

  but it is possible to use them on some other systems when

  agreements have previously been made between system service providers

  temes. To attract subscribers, these agreements must have been concluded with

  service providers located in all areas where subscribers

  born want to move. Since subscribers can potentially move

  cer on all the Earth, many similar previous agreements can be

  necessary to satisfy subscribers.

  It is said about a subscriber unit that it makes radio nomadism

  telephone when operating on one of these other systems in which previous agreements have been made. To treat nomadism, certain services

  management plans for trips outside the headquarters have been planned. The ser-

  Nomadic management vices include operations to maintain

  maintain valid location information of subscriber units, so that the system in respect of which a subscriber unit is on the move can be identified. Communications which are addressed to the "nomadic" subscriber unit

  can then be redirected to the appropriate system in response to this information.

  The nomadism management services also include operations making it possible to maintain information concerning the subscriber, whose role is to carry out authorizations and credit checks. So when a unit

  roaming subscriber tries to register or make a call through

  diary of a system with which the subscriber unit is not registered, the system

  may obtain assurances that it will receive payment for the services requested.

  Typically, telecommunication switching nodes

  Radio stations treat each other on an equal basis to provide each other with nomadic management services. In other words, each switching node has an egalitarian status vis-à-vis the provision of nomadic management services. For example, GSM (Global System for

  Mobile communications) assigns subscriber units to switching centers

  of mobile home units (MSC). A register of connecting places

  ment (HLR) is established for each subscriber unit in the home MSC of the subscriber unit. The HLR contains a complete profile of the subscriber and the subscriber unit. The HLR also stores location data that identifies any MSC to

  in respect of which the HLR subscriber unit is in a radio nomadic situation

  telephone. When a nomadic (i.e. nomadic) subscriber unit registers

  registered for the first time with a nomadism MSC, the nomadism MSC contacts the attached MSC to inform the latter of the nomadic nomadism status and its current geographical position. The home MSC can provide authorization and, or alternatively, certify the nomad's authentication in order to appreciably verify the value of the nomad's credit for the nomadic MSC. If nomadism is authorized, the MSC of nomadism establishes

  a register of places of visit (VLR) for the nomad. Communications (i.e.

  say those addressed to the subscriber unit) are first sent to the nomadic home MSC in response to the nomadic telephone number, his MIN or some other identification (ID). These communications are then redirected to the nomadic MSC by the home MSC, so that the

  Nomadism MSC can establish communication with the nomad.

  While the conventional technique has proven effective in providing nomadic management services, it has serious drawbacks as the number of radio telecommunications switching nodes increases. In addition, the number of these switching nodes continues to increase due to the expansion of radio telecommunications services. These increases are the result of the extension of radio telecommunications services to new areas and the provision of new radio telecommunications services in areas

  already covered by existing systems.

  If "N" represents the number of systems wishing to provide roaming management services to each other, then the number of potential contacts conventionally necessary to enable roaming between the N systems is (N-1) 2. In addition, (N-1) 2 legal contracts must be signed between the different service providers, and each service provider must be in accordance with the laws, prices, rights (in particular the attributions in

  carrier frequencies), and regulations related to the establishment of

  communications with the N-1 other service providers. In addition, service providers use equipment of various types. The conventional technique requires that each of the N systems is compatible with all types of equipment. By

  Consequently, traditional nomadic management services cause difficulties.

  expensive and complex cultures when the number of radio telecommunications service providers increases and nomadic management services

  are insured on a growing number of telecommunication systems

radio.

  There is therefore a need for a nomadic management system that is both global, less complex and less expensive.

  The following description, intended to illustrate the invention, aims

  to allow a better understanding of its characteristics and advantages; it is based on the appended drawings listed below, in which identical reference numbers designate identical elements in all the figures:

  FIG. 1 represents, at a higher level, the diagram of an environment

  inside which a radio telecommunications system can operate

  to argue; FIG. 2 represents, on a smaller scale, a diagram of such an environment; Figure 3 is a block diagram showing the hardware equipment used in a multimode type subscriber unit; Figure 4 is a flow diagram of an activation process; Figure 5 is a flow diagram of a process used in a multimode subscriber unit; Figure 6 is a flow diagram of a process used in a local switching node; Figure 7 is a flow diagram of a process used in a switching node operating over a large area; and

  FIG. 8 is a flow diagram of a request process for

  arrival mutation (from the recipient point of view), which is included in the process

  used in a switching node operating over a large area.

  The invention provides a method of providing roaming management services over a wide area for radio telecommunications units, the method comprising the following operations: a) establishing a transmission network over a wide area which has a home switching node and a "remote located" switching node; b) assigning a subscriber unit to the home switching node of the transmission network over a wide area; c) receiving a roaming contact from a subscriber unit at a local transmission network switching node; d) contacting, from the local transmission network switching node, the "remote" switching node of the transmission network over a wide area in order to assess the nomadic contact; and e) contacting the connecting node of the transmission network over a wide area from the switching node "located remotely" from the transmission network over a wide area in order to assess the contact.

nomadism.

  The subscriber unit may be a multimode unit and the method may further comprise the following operations: following a first transmission protocol in order to establish a transmission session between the subscriber unit and the transmission network over a extended area; and follow a second transmission protocol to establish a transmission session between the subscriber unit and the

local transmission network.

  The operation of following the first transmission protocol may include the operation of determining the geographic location

of the subscriber unit.

  The method may further include the operation of:

  mine, in the remote switching node which belongs to the transmission network over a wide area, if it is necessary to start a transmission session

  with the subscriber unit using the first or second transmission protocol

if we.

  The determination operation may include the following operations

  vantes: record data describing whether a previous transmission session

  with the subscriber unit used the first or second trans-

  mission; start a transmission session with the subscriber unit by

  using the first transmission protocol when the first transmission session

  mission with the subscriber unit used the first transmission protocol; and initiating a transmission session with the subscriber unit using the second transmission protocol when the previous transmission session

  with the subscriber unit used the second transmission protocol.

  The method may further include the step of locating the remote switching node which belongs to the transmission network

  over an extended area near the switching node of the transmission network

local mission.

  The method may further include the step of receiving data in the switching node of the local transmission network from the subscriber unit, the data indicating that the subscriber unit is

  assigned to a node included in the transmission network over a wide area.

  The method may further comprise the operation of arranging the transmission network over a large area and the local area network so that the area

  covered by the local network is included in the area covered by the trans-

mission over a large area.

  The invention further provides a method of providing nomadic management services over a wide area for radio telecommunications units, the method comprising the following operations: a) establishing a transmission network over a wide area which has a first multiplicity switching nodes and a radio coverage area of the network which extends substantially over the entire surface of the Earth; b) distribute connecting assignments for

  a second multiplicity of multimode subscriber units among the first multi-

  plicity of switching nodes of the transmission network over a wide area;

  c) locating a selected node of the first multiplicity of com nodes

  mutation near a local switching node of a local network; d) receiving roaming contacts from part of the second multiplicity of subscriber units in the local switching node; e) contact,

  from the local switching node, the selected node of the transmission network

  mission over a large area to assess nomadic contacts; and (f) contacting various nodes of the first multiplicity of switching nodes from the selected node to evaluate the roaming contacts, the various nodes of the first multiplicity of switching nodes being identified by

  response to the connecting assignments that were distributed in operation b).

  FIG. 1 shows a diagram, at a higher level, and FIG. 2 a diagram at a lower level, of an environment inside which a radio telecommunications system 10 can operate. As shown in Figures 1 and 2, the system 10 includes a wide area transmission network (WACM) 12 and any number of local transmission networks (LCN) 14. In the preferred embodiment, the WACN 12 is a transmission network using satellites. WACN 12 provides a radio network coverage area over a wide area, which extends substantially over the entire surface of the Earth through the use of a constellation of nodes.

  switching placed in vehicles of the satellite type, i.e. satellites

  lites, (SV) 16 arranged in space. For clarity, Figures 1 and 2 do not

  show that a small number of these satellites 16.

  Inside the WACN 12, the satellites 16 communicate with devices placed on the ground, by means of a number, which can range up to several hundreds, of nodes acting as central exchanges (CSO) 18, of which Figures 1 and 2 show only a small number, and of a number which can go up to several million units of multimode subscribers 20, of which Figures 1 and 2 show only a small number. The CSOs 18 and the subscriber units 20 can be placed anywhere on or near the Earth's surface. However, the CSOs 18 are preferably arranged so as to take account of geopolitical considerations. For example, each CSO 18 can control transmissions by WACN for the country in which the CSO 18 is placed. However, large countries may have more than one CSO 18, and small countries may share

CSOs with neighboring countries.

  Terrestrial transmission systems, for example conventional LCNs 14 and other components of the global public telecommunications network (PSTN) 26, can access WACN 12 via CSOs 18. Desirably, the satellite constellation 16 is configured so that at least one of the satellites 16 is at all times in sight of each of the points on the surface of the Earth. Consequently, the WACN 12 can establish, via the satellite constellation 16, a transmission circuit between any two subscriber units 20, between any subscriber unit 20 and a CSO 18,

  or between any two CSOs 18. Other telephone and trans-

  mission can be coupled to these circuits via CSO-PSTN interfaces. As shown in Figures 1 and 2, the satellites 26 communicate with satellites

  adjacent via cross links 33.

  WACN 12 can be thought of as a higher layer transmission network. Conversely, LCN 14 can be considered as transmission networks forming lower layers. The systems of

  Classic terrestrial cell transmissions represent a form of LCN 14.

  Various similar systems are known to those skilled in the art under the names of GSM, CDMA, JDC, USDC, AMPS, etc. Each LCN 14 has a local radio coverage area that is covered by, or included in, the WACN 12 radio coverage area. Up to several thousand LCN 14 can be produced worldwide, and there is no requirement that LCN 14 belong to a common type. Each LCN 14 is controlled by a local mobile unit switching center (MSC) 28. Any number of base stations 30 are coupled to a local MSC 28 and provide radio transmitters and receivers (not shown) through which radio transmissions can take place with multimode subscriber units 20 located within the LCN radio coverage area. A number of these systems allow roaming between LCNs using network roaming standards, such as GSM or IS-41. These standards allow nomadism only between LCN who use a

  common standard and have direct transmissions from one MSC to another.

  In a typical scenario, a subscriber will wish to communicate via any available LCN 14 rather than via WACN 12, since transmission services, including

  transmission of nomadism, will be very likely to be less expensive. Any-

  times, WACN 12 is available on substantially the entire surface of the Earth

  to multimode subscriber units 20 when an LCN 14 is not available. Natu-

  In reality, the preference for an LCN 14 is not a requirement of the invention.

  tion, and nothing prevents a multimode subscriber unit 20 from communicating through WACN 12 even when and where an LCN 14 is available for

  provide transmission services.

  Transmissions by WACN of subscriber units 20 take place via radio frequency (RF) transmission links 32 with satellites 16. Communications by LCN of subscriber units take place via

  RF 34 transmission links with base stations 30. Desirably

  table, the RF transmission links 32 and 34 use transmission protocols

  sufficiently different to minimize interference within common radio coverage areas. A transmission protocol represents the rules relating to the times, frequencies, and / or codings, procedures, forms and conventions that two devices follow to communicate

  together. Therefore, RF transmission links 32 employ a proto

  communication school which will hereinafter be called protocol A, and the links of

  RF transmission 34 employ a transmission protocol which will be called here

  after protocol B. The particular nature of protocols A and B is irrelevant

  tance in the context of the invention.

  According to the preferred embodiment of the invention, nomadism management services are provided by WACN 12 to any number of LCNs 14, in relation to any multimode subscriber unit 20, in a simple and efficient manner. . CSOs 18 and MSCs 28 are substantially conventional radio telecommunications switches. These switches perform processing operations, which will be discussed below, under software control. Generally, a multimode subscriber unit 20 is assigned to a CSO 18, which

  subsequently adopts, for this subscriber unit, the role of a "connecting node"

  ment "within WACN 12. Out of the entire population of CSO 18 and subscriber units 20, connecting assignments are distributed among the CSO 18 of WACN 12. Any CSO 18 which is not not the attachment node can play, for a subscriber unit 20, the role of a node "located remotely" inside the WACN 12. By way of example, FIGS. 1 and 2 show a CSO 18 ' as

  home node and an 18 "CSO as a remote node.

  Similarly, a subscriber unit 20 can be assigned to a local home MSC 28, which has been agreed to store subscription records in the home location register of the CSO 18. When a

  subscriber unit 20 attempts to communicate through some

  conch local MSC 28 other than the local home MSC, there is a nomadic situation. In the context of the present example, FIG. 1 refers to a

  Home local MSC 28 which is MSC 28 ', and Figures 1 and 2 refer to

  Refer to a local nomadism 28 MSC, which is the MSC 28 ". In case of nomadism on the MSC 28", nomadism management services are preferably provided exclusively via the CSO 18 placed near the MSC 28 ". , if this CSO 18 is a home CSO 18 'or a remote CSO 18 ", the local nomadism MSC 28" follows the same process to obtain nomadism management services. Figures 1 and 2 show only a single local MSC of nomadism 28 "associated with a single CSO 18. However, any number of local MSC

  28 "nomadism can be associated with a single CSO 18.

  This process involves contacting, or, otherwise, establishing a transmission link 36 with the CSO "located at distance" 18 "being nearby. The local nomadic MSC 28" does not need to contacting home nodes to provide roaming services to subscriber units 20. Thus roaming management services are provided by establishing agreements with only WACN 12 providers instead of

  either with a multitude of potential "connecting" service providers.

  Likewise, the local nomadism MSC 28 "needs only to satisfy interface requirements with a single CSO 18 instead of a plurality of interface requirements imposed by any number of diverse switching centers. In addition, by supplying the appropriate set of standards for exchange functions between equipment from different manufacturers, any CSO 18 can connect to numerous MSCs 28 capable of each using a different number of support interfaces. nomadism. In addition, in most cases nomadism LCN 14 does not need to be concerned with meeting transmission requirements between different geopolitical jurisdictions, including rules and regulations and payment of fees, for obtaining roaming management services Figure 3 shows a block diagram of a multimode subscriber unit 20. The subscriber unit 20 has a signal control and processing section 38. The section 38 is coupled to transceivers 40 and 42 belonging to the respective types A and B, to a memory 44 and to an input / output (I / O) section 46. Section 38 includes a microprocessor or other control components and associated peripheral devices in addition

  components used to process communications traffic. The part of com-

  command of section 38 causes the subscriber unit 20 to execute processing operations defined by computer software contained in the memory 44. The memory 44 contains

  in addition tables, databases, variables, and other structures

  storage structures which are used during the operation of the subscriber unit 20. The I / O section 46 contains all kinds of user or electronic interfaces between the subscriber unit 20 and the world, outside the subscriber unit 20. These interfaces may include a keyboard, a display, a microphone, a speaker, etc. The software stored in memory 44 includes a program 48 associated with protocol A, a program 50 associated with protocol B and a program

  general 52. Program 48 associated with protocol A contains software allowing

  as long as operating the multimode subscriber unit 20 on the WACN 12 (see FIGS. 1 and 2) via the RF transmission links 32 (see FIG. 2) using protocol A. The transceiver 40 processes the communications which take the link 32 using the protocol A. The program 50 associated with the protocol B contains software which allows the multimode subscriber unit 20 to operate on an LCN 14 (see FIGS. 1 and 2) via an RF 34 transmission link (see the

  FIG. 2) using protocol B. The transceiver 42 processes the communications

  tions using link 34 and using protocol B. There is no requirement that the transceivers 40 and 42 be similar to each other as regards

  frequencies, modulation formats, coding techniques, etc. The pro-

  general gram 52 contains common software for operation according to protocol A or B or independent of such operation. This software controls the I / O section 46 and determines whether to execute the program 48 associated with protocol A or the program 50 associated with protocol B. FIG. 4 is a flow diagram of an activation process 54. Generally, the process 54 is performed to customize the system 10 and a newly acquired multimode subscriber unit 20 so that the newly acquired subscriber unit 20 can be used on the system 10. While Figure 4 shows a sequencing particular of tasks, the skilled person understands

  dra that the tasks do not necessarily have to follow the indicated sequence.

  In task 56, data describing the newly acquired subscriber unit 20 and the subscriber himself is collected. This data contains

  information regarding the identification of the subscriber unit, information

  identifying subscriber identification, billing information, software packages to be activated, and other information ordinarily collected during the activation of conventional radiotelephones. In addition, a task 58 is executed to assign a node acting as home CSO 18 'for the subscriber unit 20 within WACN 12, and a task 60 is performed to assign to the subscriber unit subscriber 20 a subscriber unit identification (ID) on the WACN. Desirably, the subscriber unit identification ID which is assigned during task 60 is consistent with the assignment made during task 58 for the home CSO node 18 '. Other WACN nodes 12 can uniquely identify a home CSO node 18 'of the subscriber unit by evaluating the identification

Subscriber unit ID.

  A task 62 stores a subscriber profile in a home locations register (HLR) 64 (see FIG. 2) located in the home CSO 18 '. The subscriber profile is a relatively complete record of information concerning the subscriber and the subscriber unit 20. A task 65 stores in the subscriber unit the subscriber unit identification ID on the WACN . As discussed in detail below, subscriber unit 20 uses its subscriber unit identification ID on the WACN to identify itself when operating on an LCN 14 or on WACN 12. Task 66 is optional. Task 66 repeats, for a particular chosen LCN 14, the assignments of identification and identification ID. So,

  through task 66, subscriber unit 20 can have a rat LCN

  spot 14 and an identification ID which identifies the subscriber unit 20 for the home LCN 14. Task 66 is optional since nothing prevents any LCN 14 wishing to be the home LCN of a multimode subscriber unit 20 to adopt, on its own initiative, the activation of WACN. In this case, a multimode subscriber unit 20 uses its identification ID on the WACN to

  operate on LCN 14 and WACN 12. Figure 5 is a flow diagram of process 68 followed by a unit

  multimode subscriber. Desirably, substantially all of the multimode subscriber units 20 carry out a process analogous to that described in Figure 5. Process 68 is defined via software stored in memory 44 (see Figure 3).

  The process 68 includes a task 70 which identifies the networks

  available for the provision of transmission services. Specifically, the task determines whether WACN 12, LCN 14, or these two networks are available when and where task 70 is performed. Task 70 checks the transmission channels of the predetermined protocols A and B in order to identify the available networks. Then, an interrogation task 72 determines whether an LCN 14 will be used in the continuation of the transmission services. According to a typical scenario, any LCN 14 will be preferred to WACN 12 since transmission charges are less costly there. However, this is not an obligation. Precise selection criteria

  used in task 72 are irrelevant in the context of this description

  tion. When task 72 determines that an LCN 14 is used, a task 74 selects protocol B. The selection of protocol B has the effect that the sessions

  transmitting devices will use transceiver 42 and be controlled

  dees by the program 50 associated with protocol B (see FIG. 3). Next, a task 76 establishes roaming contact with LCN 14, assuming that subscriber unit 20 is not already registered to operate on LCN 14 and that subscriber unit 20 is, in fact , a nomadic unit. The nomadic contact is made by sending a registration request message to a local MSC 28 (see Figure 2). The registration request message is sent using the RF transmission link 34 and protocol B via a base station (see Figures 1 and 2). The registration request message includes the identification ID on the WACN of the subscriber unit. Although this is not shown in Figure 5, if the subscriber unit 20 is already registered on LCN 14, task 76 can be omitted. If the subscriber unit 20 is not a mobile unit, then any contact or message sent to an MSC 28 can be considered as a home contact and not as a roaming contact. A nomadic contact registration request message may contain the identification

  ID on the WACN of the subscriber unit, but this is not a necessity.

  After task 76, an interrogation task 78 determines whether or not access to the network is granted. The process 68 can remain stationed on the task 78 until a message is received from the contacted network, which performs its determination. However, additional tasks (not shown) can be provided to prevent the control of the program from remaining stationed on task 78 in the event that no return message is sent. The return message must indicate whether the registration request has been accepted (i.e. if

  access has been granted) or has been denied.

  If access has not been granted, then a task 80 performs an appropriate error handling process. Task 80 can for example inform the user of the problem, repeat the registration request message a number of times, etc. After task 80, the program command loops on the

  task 70 in order to continue to identify available networks.

  When task 78 determines that access to the contacted network has been granted, an interrogation task 82 determines whether or not a communication start (send) event is occurring. A communication start event can occur when, for example, a user dials a telephone number on a dial to make outgoing communication. If a communication start is occurring, a task 84 performs a communication start process. Task 84 has

  classic communication establishment, communication control activities

  cation, and communication interruption. After task 84, the command to

  program loop on task 70 in order to continue to identify available networks

  targets. When task 82 determines that no outgoing communication occurs, a polling task 86 determines whether an incoming event

  (outcome) of communication is or is not happening. An event-

  Communication termination may occur when, for example, a third party attempts to call a subscriber unit 20. In this situation, the network on which the subscriber unit 20 is currently registered will send a message. paging at subscriber unit 20. The paging message will include identification data which substantially designates subscriber unit 20. Thus, a task 86 determines whether a similar paging message addressed to subscriber unit 20 may or may not have been received. If a communication arrival is occurring, a task 88 performs a process

  communication arrival. Task 88 includes the classical activities of

  communication failure, communication control and communication interruption. After task 88, the program command loops over the task in order to continue to identify available networks. Likewise, when task 86 determines that no communication arrival is being

  occur, program command loops to task 70.

  We return to task 72. When task 72 decides that an LCN 14 is not used, a task 90 selects protocol A. The selection of the proto-

  cole Has caused subsequent transmission sessions to use the transmitter-

  receiver 40 and will be controlled by the program 48 associated with the protocol A (see FIG. 3). Then, an interrogation task 92 determines whether or not a registration event has occurred. In the preferred embodiment, a registration event occurs when a subscriber unit 20 has moved a predetermined distance since its last registration with WACN 12 or if a predetermined duration has passed since the last recording of

  subscriber unit 20 to WACN 12. When no record event-

  ment has occurred, the program command proceeds to task 82 to check whether or not communication start and end events are being

happen.

  When task 92 determines that a registration event has occurred, task 94 sends a registration request message to WACN 12. The registration request message is sent using the transmission link. RF 32 and protocol A via satellite 16 (see Figures 1 and 2). The registration request message includes the identification ID of the subscriber unit to the WACN. After task 94, or in connection with it, task 96 performs a location determination process in order to determine

  the current geographic location of the subscriber unit 20. In the real-time mode

  In a preferred embodiment, task 96 checks position information broadcast by signaling satellites 16 and assesses the Doppler propagation and signal propagation delays in transmissions carried out with WACN 12 for

  determine the location. As a result of task 96, WACN 12 finds the location

  tion of the subscriber unit. After task 96, program control changes to

  task 78 to assess whether access has been granted to WACN 12.

  Therefore, the subscriber unit 20 operates in modes

  multiples ensuring communication with multiple transmission networks.

  When nomadic contacts have been established towards an LCN 14, the subscriber unit 20 identifies itself using its identification ID on the WACN. From this identification ID on WACN, LCN 14 can conclude that the subscriber unit

  has a home node in WACN 12.

  Figure 6 is a flow diagram of a process 98 used by a local switching node. The process 98 is executed by a local MSC 28, or else by a local MSC 28 associated with its base stations 30 (see FIG. 2). Desirably, substantially all local MSCs 28 and their base stations 30 perform a process similar to that depicted in FIG. 6. All transmissions are made with a subscriber unit 20 which takes place through of an MSC 28 are compatible with protocol B. Process 98 has many sub-processes. A nomadic contact process, a communication request process 102

  arrival (from the recipient point of view) and a process 104 for requesting

  outgoing munication (from the transmitting point of view) are included among these

  process. For the sake of clarity, many other processes, carried out by the

  MSC 28, as a connecting contact process, is not shown.

  The nomadic contact process 100 is performed when a nomadic contact is received from a subscriber unit 20. A nomadic contact occurs when a subscriber unit 20 attempts to register to obtain transmission services on the LCN 14. The process 100 takes place for all the subscriber units 20 which have an identification ID on the WACN independently

  CSO 18 (see Figures 1 and 2) which are the attachments of the subscriber units.

  The process 100 includes a task 106 which evaluates the identification ID

  of the subscriber unit on the WACN. In response to task 106, an interrogation task

  gation 108 determines whether the subscriber unit has a convenient home node

  taken from WACN 12. If the identification ID of the subscriber unit does not indicate a home node included within WACN 12, then task 110 performs an appropriate error handling process. If task 110 is being performed, the subscriber unit making a roaming contact may have a home node on any network other than WACN 12. Provided that LCN 14 has entered into previous agreements with this other network, task 110 can carry out conventional procedures making it possible to obtain nomadism management services. If no previous agreement has been made, task 110 can simply ignore the nomadic contact, or, preferably, send a refusal of access message. After task 110, the program command leaves the

  process 100. When task 108 determines that a nomadic contact pro-

  comes from a subscriber unit 20 having its attachment in WACN 12, a task 112 establishes a transmission session with the node CSO "located at a distance" 18 "which is assigned to the MCS 28" (see FIG. 2) performing the process 100. The transmission session can be established using land line links 36 formed via the PSTN 26 (see FIG. 2). As discussed above, the assigned CSO node 18 "is desirably located near the MSC 28" relative to the domain of WACN 12. The assigned MSC 28 "desirably remains the same regardless of the home CSO 18 of the subscriber unit, so each

  MSC 28 follows a unique process for obtaining noma management services

  say with respect to all subscriber units 20, and all CSOs 18 pre-

  feel like a single node for each local MSC 28.

  After task 28 has made contact with the assigned "remote located" CSO 18, task 114 transmits the registration request from the subscriber unit to the "remote located" node of WACN 12 in order to evaluating the nomadism contact This registration request includes the identification ID of the subscriber unit The nomadism contact is evaluated via the reception of nomadism management services relative to the requesting subscriber unit. Then, an interrogation task 116 determines whether or not access is granted to the nomadic subscriber unit.The process 100 can remain stationed on task 116 until a message is received from the CSO located at 18 "distance that was contacted, before it made its determination. However, additional tasks (not shown) can be provided, which prevent the program command from remaining stationed on task 116 if no return message is sent. If access is not granted, then task 118 performs an appropriate error handling process. Task 118 can for example send a message denying access to the requesting subscriber unit 20 via the RF transmission link 34 (see FIG. 2). After task 118, the program command leaves the

process 100.

  When task 116 determines that access has been granted, a task constructs a visitor location register (VLR) 122 (see Figure 2) for the nomadic subscriber unit 20. VLR 122 contains, among other things, a

  subset of information from the HLR 64 (see Figure 2) of the nomad.

  This information is sent back to the nomadism 28 "MSC from WACN 12. In addition, task 120 can assign a temporary identification ID to

  the nomadic subscriber unit 20 while it is in a nomadic situation vis-

opposite the MSC 28 ".

  After task 120, task 124 sends an access agreement message to the mobile subscriber unit 20. The access agreement message is sent according to protocol B. At this time, the unit d subscriber 20 can operate on LCN 14 in

  as a nomad. After task 124, the program command exits the program

stopped 100.

  The incoming call request process 102 is performed in order to process a communication establishment which is being directed to a subscriber unit, such as the mobile subscriber unit 20. The request to making a call succeed in the subscriber unit can be received in the MSC 28 from the node located at a distance 18 "from the WACN 12, but it can also come from the PSTN 26. The process 102 is carried out in a conventional manner,

  that is to say performs a person search targeting the subscriber unit 20 identi-

  trusted in the request using protocol B transmissions, determines whether or not to respond to the communication, controls any communication to which it

  is answered, and interrupts the communication once it has ended.

  The outgoing communication request process 104 is carried out so as to process a communication establishment request sent in a registered subscriber unit, for example a nomadic subscriber unit 20. The outgoing communication request is received in the MSC 28 on the part of the subscriber unit 20 via communications according to the protocol B. Conventional processes are used to establish the communication via the PSTN 26. However, according to another embodiment, the communication is established via WACN 12. Process 104 establishes communication, monitors communication, and terminates communication upon completion. Figure 7 is a flowchart showing a process 126 used in a switching node operating over a large area. Process 126 is performed by a WACN CSO 18 12. Desirably, substantially

  all the CSOs 18 carry out a process similar to that described in FIG. 7.

  Process 126 has many sub-processes. A trial-

  sus 128 of reception registration request, an arrival communication request process 130 and a communication request request process 132

  departure are included among these sub-processes. In order not to complicate a name-

  many other processes performed by CSO 18 have been omitted. The 128 process of

  reception registration request is made when a registration request

  trement is received from a subscriber unit 20. The registration request can arrive at CSO 18 via an RF transmission link 32 (see Figure 2) operating according to protocol A, and a satellite 16. According to Another possibility is that the registration request can reach CSO 18 via an LCN 14 using protocol B, an RF transmission link 34 (see Figure 2) and an MCS 28 performing the process 100 (see Figure 6). The CSO 18 receiving the registration request can either be an attachment CSO 18 ', associated with the unit

  subscriber 20 requesting, or a CSO located at 18 "distance.

  Process 128 includes an interrogation task 134 which determines whether the registration request received from a subscriber unit 20 has arrived via an LCN 14. If the registration request has not arrived via an LCN 14, it was then received directly from the subscriber unit 20 according to a protocol A. In the event of reception according to the protocol A, a task 136 clears a "local network" flag in order to record data which describe the protocol that the subscriber unit 20 uses for this transmission session and the subsequent sessions. The transmission protocol used by subscriber unit 20 for subsequent transmission sessions is normally, by default, that according to which data was recorded during a transmission session

  anterior. Next, a task 138 performs a location determination process.

  reading. Task 138 complements task 96 (see Figure 5). During task 138, transmissions according to protocol A take place to identify the location of subscriber unit 20. When task 134 determines that the registration request arrives via an LCN 14, a task 140 sets the "local area network" flag in order to record data which describes the protocol that the subscriber unit 20 is using for this session and the subsequent transmission sessions. In addition, when multiple LCNs 14 are assigned to CSO 18 performing process 128, task 140 can register the identity of LCN 14 through which the registration request was received so that future communications which will result in subscriber unit 20 are routed through

this LCN 14.

  After tasks 138, and, alternatively, 140, an interrogation task 142

  determines whether or not CSO 18 performing process 128 is CSO 18 of rat-

  subscriber unit spotting 20. Task 142 can make this determination by evaluating the subscriber unit identification ID on the WACN, which includes the

  registration request. If the CSO 18 considered is not the connection node

  ment, it is therefore a node located at a distance from WACN for subscriber unit 20.

  When the CSO 18 considered is a remotely located node, a task 144 sends

  a registration request message and location information

  rante concerning the subscriber unit 20 at the node of attachment of the subscriber unit in order to evaluate the nomadic contact. For the attachment node, the identity of the CSO 18 considered can depend on the location information. These credentials will tell a home node how

  contact subscriber unit 20 in the future.

  After task 144, an interrogation task 146 determines whether or not access has been granted to subscriber unit 20. Process 128 can remain stationed on task 146 until a message is received from the home CSO 18 contacted, before the determination is made. However, additional tasks (not shown) may be included in order to prevent the program command from remaining parked on task 146 if no return message is sent. If access is not granted, then a task 148 performs an appropriate error handling process. Task 148 can for example return a message denying access to the requesting subscriber unit. This message is returned according to the protocol through which the registration request was received. Protocol A transmissions are returned via a satellite 16 and Protocol B transmissions are returned via an LCN 14. When task 148 determines that access has been granted, a task establishes a visitor location register (VLR ) 152 (see Figure 2) for

  the nomadic subscriber unit 20. The VLR 152 contains a subset of the information

  tions contained in the nomad's HLR 64 (see Figure 2). This information is obtained from the home CSO 18 in a message which responds to the registration request message. Task 150 is optional, insofar as protocol B transmissions are used, since the nomadic MCS 28 "(see Figure 2) will maintain its own VLR 132 (see Figure 2) to support a subscriber unit nomadic. However, we can improve the

  performance by establishing a VLR 152 even if it may not be absolute

* necessary. This task is not optional when transmissions following

protocol A are used.

  We now return to task 142. When the CSO node 18 of WACN 12 which receives a registration request message from a subscriber unit is the home node, a task 154 performs a process

  authorization. For example, task 154 applies an authentication algorithm.

  appropriate fication in response to a cryptographic key which has been transmitted to the home CSO 18 via the registration request. In addition, task 154 may examine billing records to determine the credit value of subscriber unit 20. If a record request has been sent to the home CSO 18 from a remote CSO 18, task 154 desirably returns the results of the authorization process to this CSO

  located at distance 18, the CSO located at a distance then being waiting in sta-

  operation on task 146, after which it stops (this is not shown). Assuming that authorization is obtained, a task 156 updates the HLR 64 of the subscriber unit (see Figure 2) using a current indication of the

location of the subscriber unit.

  After each of tasks 148, 150 and 156 has been completed, the pro-

  cessus 128 performs a task 158. The task 158 returns to the subscriber unit 20 an access agreement or access refusal message. Access is granted or denied depending on the authorization process performed in the home CSO 18 during task 154. If the registration request arrived via an LCN 14, then task 158 returns to the local MCS 28 via the link 36 (see FIG. 2) the message of agreement or refusal of access. This message will be returned to subscriber unit 20 according to protocol B during tasks 118 or 124 (see Figure 6). If the registration request arrived via satellite 16, then task 158 returns the message of agreement or refusal of access via satellite 16 to subscriber unit 20, to

  using protocol A. After task 158, process 28 ends.

  FIG. 8 is a flow diagram of the process 130 for the request for an incoming call, which is carried out by a CSO "located remotely" and, alternatively, "home" 18 of the WACN 12. The process 130 generally attempts to succeed a communication to a subscriber unit 20. The process includes an interrogation task 160, which determines whether or not the CSO 18 carrying out the process 130 is the home node of the called subscriber unit, in the WACN 12. If the CSO 18 carrying out the process 130 is the attachment node, a task 162 provides the current location of the subscriber unit 20, by searching the HLR 64 (see FIG. 2). An update of the

  localization is performed each time the subscriber unit 20 re-registers.

  However, this location data does not need to define the location of

  more precisely than by providing the identity of a CSO 18 through

  diary of which the subscriber unit 20 can be reached. After the task 162, a task 164 transmits the incoming communication request to the CSO 18 which is associated with the current location of the subscriber unit 20. If the current location of the unit

  subscriber 20 is the home CSO 18, then task 164 is transmitted simple-

  the incoming call request to itself. Otherwise, task 164

  transmits the incoming communication request to a remote CSO 18.

  After task 164, when task 160 has determined that the CSO 18 performing the process 130 is not the home CSO 18, an interrogation task 166 determines whether a location register (LR), for example an HLR 64 or a VLR 152 (see Figure 2), is active with respect to the called subscriber unit 20. If a location register is active, then an attempt to find the called subscriber unit 20 must be attempted via this CSO 18. However, if no location register is active, then a task 168 addresses the request for

  incoming communication to the home CSO 18 of the called subscriber unit.

  Of course, if the CSO 18 performing task 168 is the home CSO 18 of the called subscriber unit, then an appropriate error handling process can be performed. After task 168, the program command leaves the

process 130.

  When task 166 determines that an HLR or VLR is active with respect to the subscriber unit called 20, an interrogation task 170 determines whether the "local area network" flag is set with respect to the unit subscriber 20

  called. The "local network" flag was set or erased during an inquiry

  previous registration during tasks 140 or 136 (see Figure 7). If the flag

  "local network" is positioned, a task 172 transmits the communication request

  from the recipient point of view to the appropriate MSC 28. MSC 28 will search for the subscriber unit called via process 102 (see Figure 6) using protocol B transmissions. If the "local network" flag is cleared, a task 174 will search for the subscriber unit called 20 via satellite 16 using protocol A transmissions. After tasks 172 or 174, program control exits process 130 after performing

  other conventional inbound call request tasks, which relate

  relate to communication establishment activities, community control

  communication notification and interruption.

  Returning now to FIG. 7. The delay communication request process 132 is performed to process a communication establishment request originating from a registered subscriber unit 20. The outgoing call request is received in CSO 18 from a subscriber unit via transmissions according to protocol A or B. Des

  conventional treatments are used to establish communication through

  diary of PSTN 26. Process 132 establishes communication

  tion, monitors the communication and interrupts it once it is completed.

  In summary, the invention proposes an improved system and method of radio telecommunications allowing layered management of nomadism over a large area. Nomad management services are provided for the entire Earth by a single contact from a local area network switch. In addition, roaming management services are provided for the various modes of multimode subscriber units by a single contact from a local area network switch. In addition, a large transmission network provides nomadic management services for any number of local transmission networks that may be inside.

of the extended area.

  The invention has been described above in connection with embodiments.

  sation preferred. However, those skilled in the art will recognize that modifications and changes can be made to these preferred embodiments without departing from the scope of the invention. For example, the transmission network over a large area need not be global. Similarly, the management services of

  nomadism can be provided for more than two layers of trans-

  mission. Those skilled in the art will also understand that the processes and tasks currently identified can fall into categories and be organized differently in the manner described herein, while providing results.

equivalent.

  Of course, those skilled in the art will be able to imagine, from the

  systems and processes whose description has just been given simply

  illustrative and in no way limitative, various variants and modifications not coming out

of the scope of the invention.

Claims (10)

  1. Method for providing nomadic management services over a wide area for radio telecommunications units (20), said method being characterized by the following operations: a) establishing a transmission network (12) over a wide area which   has a connecting switching node (18 ') and a switching node   remotely located (18 "); b) assigning (58) a subscriber unit (20) to said home switching node (18 ') of said transmission network over a wide area (12); c) receiving (100 ) a roaming contact from said subscriber unit (20) at a local transmission network switching node (28 "); d) contacting (112), from said local transmission network switching node (28 "), said switching node located at a distance (18") from said transmission network over a wide area (12) in order to evaluate said contact nomadism; and e) contacting (114) said connecting switching node (18 ') of said transmission network over an extended area (12) from said switching node located (18 ") away from said transmission network over an area   scope (12) in order to evaluate said nomadic contact.   2. Method according to claim 1, o said subscriber unit is a multimode unit, said method being characterized by the following operations: following (90) a first transmission protocol in order to establish a transmission session between said unit subscriber and said transmission network over a wide area; and following (74) a second transmission protocol to establish a transmission session between said subscriber unit and said local transmission network. 3. Method according to claim 1, characterized in that: said operation a) establishes said transmission network on an area   extended so that it has a first multiplicity of switching nodes   tion, comprising said home switch node and said remote switch node; said operation b) distributes attachment assignments for a second multiplicity of subscriber units among said first multiplicity of switching nodes of the transmission network over a wide area; said operation c) receives nomadic contacts from a   part of said second multiplicity of subscriber units at said communication node   local transmission network mutation; said operation d) contacts, from said local transmission network switching node, said switching node "located at a distance" from said transmission network over a wide area in order to evaluate each of said contacts; and   said operation e) contacts various nodes of said first multipli-   city of switching nodes in order to evaluate said nomadic contacts, the-   said various switching nodes being identified according to said assignments   of attachment distributed during said operation b).   4. Radio telecommunications system with management services   nomadism over a wide area arranged in layers, said system being charac-   terified by: a transmission network (12) over a wide area, which has a connecting switching node (18 ') and a remote located switching node (18 ") and which is configured so as to have a large area radio coverage; and a local area network (14) which has a local switching node (28 ") and which is configured to have a local radio coverage area included in said large radio coverage area, said local switching node (28 ") being configured to communicate with said remote located switching node (18") to evaluate a nomadic contact received (100) from a multimode subscriber unit (20) which has an assignment of attachment in   said home switching node (18 ').   5. Radio telecommunications system according to claim 4, characterized in that: said nodes of said transmission network over a wide area are   configured to follow (90) a first transmission protocol to establish   blocking a transmission session with said subscriber unit; and said local switching node of said local area network is configured to follow (74) a second transmission protocol to establish a   transmission session with said subscriber unit.   6. Radio telecommunications system according to claim 4, characterized in that: said transmission network over a wide area has a first multiplicity of switching network transmission nodes over a wide area, which comprises said home switching node and said remote switching node; peg assignments for a second multiplicity of subscriber units are distributed among said first multiplicity of switching nodes; a portion of said second multiplicity of subscriber units makes roaming contacts (100) in said local area network switching node; and said local switching node communicates (114) with said remotely located switching node belonging to said transmission network over a   extended area to assess each of said contacts.   7. Method for providing nomadic management services over a wide area for radio telecommunications units, said method being characterized by the following operations: a) establishing a transmission network (12) over a wide area which has a first multiplicity switching nodes and a network radio coverage area that covers substantially the entire surface of the Earth;   b) distribute connecting assignments for a second multiple   multiplicity of multimode subscriber units (20) among said first multiplicity of transmission network switching nodes over a wide area; c) locating a selected node of said first multiplicity of switching nodes near a local switching node (28 ") of a local network (14); d) receiving (100) roaming contacts from d a part of said second multiplicity of subscriber units (20) to said local switching node (28 "); e) contacting, from said local switching node (28 "), said selected node of said transmission network over a wide area (12) in order to evaluate said nomadic contacts; and f) contacting various nodes of said first multiplicity of nodes switching from said selected node in order to evaluate said contacts of   nomadism, said various switching nodes being identified as a function of-   said connecting assignments distributed during said operation b).   8. Subscriber unit (20), characterized in that it allows a user   of said subscriber unit to carry out roaming within the trans-   mission over a wide area (WACN) (12) or within a local transmission network (LCN) (14), or even both inside said WACN (12) and said LCN (14) said subscriber unit (20) being further characterized by: a radio transceiver (40) for communicating with said WACN (12) and said LCN (14); and a memory (44) for storing a first protocol (48) and a second protocol (50) to enable the subscriber unit (20) to operate   respectively inside said WACN (12) and said LCN (14).   9. Local switching node (LSN) (28 "), characterized in that it is designed to operate within a transmission network over a wide area (WACN) (12) and inside a local transmission network (LCN) (14), said LSN (28 ") being further designed to communicate with a radio telecommunications subscriber unit (20) which operates within said WACN (12), inside said LCN (14) or both inside said WACN (12) and said LCN (14), said LCN (28 ") being further characterized by: a controller that responds to radio transmission from   of said radio telecommunications subscriber unit requesting communication   said control device determining whether said remote subscriber unit   radio communications is or is not registered with said LSN; and in that, if so, said communication is made; and   if this is not the case, a message requesting registration is sent.   WACN audit, which contains a subscriber unit identity number,   bearing to said radio telecommunications subscriber unit.   10. Central switching node (CSO), characterized in that it is designed to operate inside a transmission network over a wide area (WACN) (12) and inside a network local communication (LCN) (14) having a local switching node (LSN) (28 "), said CSO node being further adapted to communicate with a radio telecommunications subscriber unit (20) operating therein said WACN (12), inside said LCN (14) or both inside said WACN (12) and said LCN (14), and with an LSN (28 ") operating inside said LCN (14), said CSO node being further characterized by: a control device which responds to a radio transmission transmitted to its destination via said LSN from said subscriber unit requesting a communication, said control device determining whether said radio telecommunications subscriber unit is registered with said CSO node; and in that, if so, said communication is made; and if this is not the case, a registration request message is sent, which includes a subscriber unit identity number relating to said radio telecommunications subscriber unit, via said WACN, at a different CSO node in which said radio telecommunications subscriber unit is registered.