GB2349780A - Transmitting mobility data between microcellular and macrocellular networks via an internet connection - Google Patents

Abstract

A method and apparatus for facilitating communications with a roaming mobile subscriber unit 58 which roams beyond a microcellular communication network 14, 16 such as a Digital Electronic Cordless Telephone (DECT) system. A first signaling device is coupled to the microcellular network, the first signaling device for encapsulating microcellular-generated data into Internet protocol data. A second signaling device is coupled to a macrocellular network 12 for de-encapsulating the Internet protocol data, when received thereat. An Internet communication channel formed between the first signaling device and the second signaling device and forming a communication path therebetween permits communication between the macrocellular network 12 and the microcellular network 14, 16.

Description

MOBILITY MANAGEMENT METHOD AND APPARATUS FOR WISS CC1NICATION SYSTBN The present invention relates generally to mobility management of a mobile subscriber unit operable in a microcellular communication network, such as a Digital Electronic Cordless Telephone (DECT) system or other Private Telephone Network (PTN). More particularly, the present invention relates to a method, and associated apparats, for facilitating communications to and from the mobile subscriber unit pursuant to the microcellular communication network when the mobile subscriber unit roams into an area encompassea by a communication network other than the Shome microcellular communication network in which the mobile subscriber unit is regularly registered.

The microcellular communication networks are interface with a macrocellular communication network, such as a Global System for Mobile communications (GSM) or other Public Land Mobile Network (PLMN). Wide-area, mobility management functions existent in the macrocellular cowmunication network are utilized by the rnicrocellular communication network to provide wide-area mobility management to the microcellular communication network. wide-area mobility of the mobile subscriber unit is permitted a the wide-area mobility management fonctions of the macrocellular communication network are used to facilitate the communication with the mobile subscriber. unit. Hhen the atobile subscriber unit roams beyond an area encompassed by the microcellurar communication network in which the mobile subscriber unit is regularly registered, calls can still be routed to and from the mobile 6ubscriber unit.

When the macrocellular communication network is formed of a GSM network, a mobility server positioned in the micrecellular comaunication network is coupled to the GSM network and appears to the GSM network as a mobile services switching center IMSC) thereof. The wide-area, mobility management functions are used by the mobility servers of both the subscriber unit's'home"network and the visitedw network into which the subscriber unit roams thereby to provide wide-area mobility to the mobile subscriber unit.

Communications between the microcellular and macrocellular communLcation networks are also permitted to be effectuated by way of the internent. Data to be communicated between the networks is encapsulated according to an Internet protocol, or the like.

BACKGROUND OF THE INVENTION Advancements in the fields of electronics and communications have permitted the introduction and commercialization of many new types of communication systems. Information can be affordably communicated tc locations and in manners previously not possible or affordable.

The field of cellu} ar telephony is exemplary of a communication system that has been made possible due to such advancements. A fixed, wireline connection is not required between a transmitting station and a receiving station in a cellular, or other radiotelephonic, communication 6y8te to effectuate communications between the stations. Because a'wireless"coxznection is formed between the transma. tting statioa and the receiving station, use of such a communication system is particularly advantageous to effectuate communications when a wireline connection cannot be conveniently or practically formed.

Various different types of cellular, and other radiotelephonic, communication systems have been implemented and others have been propose. In many parts of the world, for instaz : ce, macrocellular commuaication networks have been installe. Such networks permit mobile subscriber units positioned anywhere within the area encompassed ty the macrocellular networks to communicate pursuant to the macrocellular communication network. A macrocellular communication network typically inclues a large number of base stations positioned at spaced-apart locations throughout a geographic area. As a mobile subscriber unit moves throughout the geographical area, communications with the mobile subscriber unit are 'handed-off"to successive ones of the base stations. In one type of cellular communication system, a Global System for Mobile (GSM) communications system, control circuitry, including mobile services switching centers (MSCs) and base stations controllers (BSCs), controls communications between the base stations and the mobile subscriber unit.

And, location registers, including a home location register (HLR) associated with the mobile subscriber unit, maintain a registry of the positioning of the mobile subscriber unit in a network.

Microcellular communication networks have also been developed and iwplemented. A Digital Electronic Cordless Telephone (DECT) system is exemplary of a microcellular communication network. A microcellular commwnication network, analogous to a macrocellular communication network, also permits wireless communications to be effectuated with a mobile subscriber unit. The area encompassed by a microcellular communication network is, however, typically much smaller than the area encompassed by a macrocellular communication network.

The costs associated with a microcellular communication network are generally less than the costs associated with a macrocellular cormunication network.

However, because microcellular communication networks generally encompass limited areas, a single business, or other operator, might be required to construct more than one microcellular communication network to encompass a desired area in which mxcrocellular cormunications are to be permitted.

For instance, a microcellular communication network might be constructed to provide microcellular communication coverage encompassing a sxngle building.

A mobile subscriber unit regularly registered to communicate purauant to the microcellular communication network must be within the building, i. e., the area encompassed by the microcellular cowmunication network, to communicate therethrough.

It is sometimes desirable to permit a mobile subscriber unit, regularly registered in one microcellular communication network (the "home" network), also to c icate in another microcellular communication network (the "visited" network). For instance, a business might have separate office locations, requiring separate microcellular networks to be installe for each of the separate office locations. It is sometimes desirable, in such instances, to permit personnel regularly located at one of the office locations to be able to cornmunicate by way of a microcelllar comsunication network even when the personnel are temporari1y positioned at the other one of the office locations.

By praviding commNnication links between the separate microcellular networks, registration, and other, information pertaining to the mobile subscriber unit stored at the"home"microcellular communication network can be used to permit communications with the mobile subscriber unit, even when the mobile subscriber unit is positioned in an area encompassed by the Svìsitedz microcellular communicaticn network. various proposas have been set forth to form communication links between microcellular networks by way of a macrocellular communication network. Such proposas, however, have generally been set fort for purposes of call control und not for purposes of mobility management.

Viz. existing proposals for intercoupling the networks have not generally pertained to providing wide-area mobility to mobile subscriber units of microcellular communication networks.

Additionally, existing proposas generally require direct connections between the microcellular and macrocellular communication networks. As the operators of the macrocellular and microcellular communication networks might well be different entities, the conventional requirement for direct connections between the microcellular communication networks might sometimes be problematical.

A manner by which better to provide wide-area mobility to a mobile subscriber unit to increase the mobility permitted of the mcbile subscriber unit would be advantageous.

Additionally, a manner by which to provide for the communication of mobility management information between a microcellular and macrocellular commwnication network without requiring direct connections therebetween would also be advantageous.

It is in light of this background information related to mobility management in a cellular communication system that the significant improvements of the present invention have evolved.

SUMMARY OF THE INVENTION The present invention advantageously provides a method, and associated apparats, for facilitating communications to and from a mobile subscriber unit Operable in a microcellular communication network when the mobile subscriber unit roams into an area encompassed by a wvisited"microcellular comzunication network other than the "home" network in which the mobile subscriber unit is regularly registered.

Vide-are mobility management functions available in a macrocellular network are provided to microcellular networks by coupling the microcellular networks to the macrocellular network. Wide-area aobility is thereby provided to a mobile subscriber unit operable in a microcellular communication network. The wide-area management functions provided to the microcellular communication network permits a mobile subscriber unit to communicate by way of a microcellular communication network even when it roams into an area encompassed by a avisited network.

When the macrocellular communication network is formed of a Global System for Mobile communications (GSM) network, the microcellular communication networks include the mobility servers which appear, to the GSM network, to be mobile services switching centers (MSCs) of the GSM network. Mobility management normally provided to the mobile services switching centers of the GSM network are provided to the mobility servers of the microcellular networks. Signaling between the mobility server and the macrocellular communication network permit, for example, calls to be placed to and from a mobile subscriber unit when the subscriber unit roams beyond the microcellular communication network in which the subscriber unit is regularly registered. Location updating of the position at which the subscriber unit roams is similarly also effectuated.

In one aspect of the present invention, location information related to the position of a mobile subscriber unit is updated when the mobile subscriber unit roams into an area encompassed by a microcellular communication network other than the network in which the subscriber unit is regularly registered. A mobility server of such "visited"microcellular network receives indications of the positioning of the subscriber unit and provides information indicative thereof to a home location register (HLR) of the macrocellular communication network, The home location register (HLR) provides the visited mobility server with subscriber data related to the mobile subscriber unit and orders the "home" mobility server of the subscriber unit's home network to deregister the subscriber unit therefrom.

In an another aspect of the present invention, calls originated at a Public Switched Telephone Network (PASTIS) to be termlnated to a mobile subscriber unit of the'home' microcellular communication network are routed to the subscriber unit when the Rubscriber unit roams beyond the ShomeX network and into a visited network. In one exemplary routing method, the call is routed via the home microcellular communication neework to a gateway mobile services switching center (GMSC) of the macrocellular communication network, and the GMSC interrogates the home location register of the macrocellular network to obtain routing information to route the call to the roaming, subscriber unit. The HLR requests and receives information from the mobility server of the"roaming' microcellular network. Such information is provided to the GMSC, and the call is routed to the mobile subscriber unit, to be terminated thereat.

In another aspect of the pressent invention, a call originated at a roaming, subscriber unit is routed to a subscriber unit registered in the macrocellular communication network. And, in yet another aspect of the present invention, calls are placed between a mobile subscriber unit positioned in a'home"microcellular network to a mobile subscriber unit roaming in a'visitedF microcellular communication network. And, in yet another aspect of the present invention, the mobile subscriber unit forms a dual-mode subscriber unit. operable in both a microcellular network and a macrocellular network.

Calls are placed, or received, by the subscriber unit when the subscriber unit is positioned in its Shome microcellular network, a visited microcellular network, or within an rea encotpas9ed only by the macrocellular network.

The present =vention further advantageously permits communications between the microcellular and macrocellular communication networks by way of an Internet communication channe. Mobility management information, for example, is encapsulated according to an Internet protocol, or the like, and thereafter communicated by way of the Internet forcing a connection between the microcellular and macrocellular communication networks. Because communications between the microcellular and macrocellular communication networks are effectuated by way of the Internet, direct connections between the separate networks are not required. The Internet, already existent and readily accessible, can thereby be utilized both to facilitate data communications and also telephony communications.

In these and other aspects, therefore, mobilityenhancing apparats for a first mobility server facilitates communication with a mobile subscriber unit.

The mobile subscriber unit is operable in a first microcellular communication network of a communication system having a macrocellular communication network and at least the first microcellular communication network.

The first microcesllular communication network inclues the first mobility server. The mobility-enhancing apparats facilitates communication with the mobile subscriber unit, operable in the first microcellular communication network, in a communication network other than the first wicrocellular communication network. A storage device stores location information representative of positioning of the mobile subscriber unit. A mobility manager is coupled to the storage device and to the macrocellular network. The mobility manager at least updates the location information stored in the storage device to indicate whether the mobile subscriber unit is positioned within range of the first microcellular communication network. The mobility manager further receives macrocellular network-generated data related to the mobile subscriber unit, and the network-generated data is used for the updating of the location information.

A more complete appreciation of the present invention and the scope thereof can be obtained from the accompanying drawings which are briefly summarized below, the following detailed description of the presently- preferred embodiments of the invention, and the appende claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE I illustrates a functional block diagram of a communication system which inclues an embodiment of the present invention as a portion thereof.

FIGURE 2 illustrates a functional block diagram of a portion of the communication systecrt shown in FIGURE 1 used dring operation of an embodiment of the present invention to update the location of a mobile subscriber unit when the mobile subscriber unit roams into an area enconlpassed by a microcellular communication network other than the"home"microcellular network in which the subscriber unit is regularly registered.

FIGURE 3 illustrates a functional block diagram of a portion of the communication system shown in FIGURE 1 used during operation of an embodiment of the present invention when the mobie subscriber unit roams into an area encompassed by a mlcrocellular communication network other than the'home network in which the subscriber unit is regularly registered.

FIGURE 4 illustrates a portion of the communication system shown in FIGURE 1, used during operation of an embodiment of the present invention to route a call originated ty a mobile subscriber unit when the mobile subscriber unit is positioned in an area encompassed by a microcellular communication network other than the homew network in which the subscriber unit is regularly registered.

FIGURE 5 illustrates a portion of ede communicstion system shown in FIGURE 1 used during operation of an embodiment of the pressent invention to route a call between subscriber units positioned in different microcellular communication networks.

FIGURE 6 illustrates a functional block diagram of a communication system which inclues another embodiment of the present invention.

DETAtI13D DESCRIPTION Referring first to FIGURE l, a communication system, shown generally at 10, includes an edbodiment of the present invention as a portion thereof. The communication system 10 is a multi-network communication system, here shown to include a macrocellular communication network 12, a first microcellular communication network 14, and a second microcellular communication network 16.

The microcellular communication network 12, for purposes of illustration, in the exemplary embodiment, is formed of a Global Systems for mobile communications (GSM) network. In other embodiments, the macrocellular communication network 12 is alternatively formed of another type of Public Land Mobile Network (PLMN).

Analogously, the first and second microcellular communication networks 14 and 16, respectively, are, in the exemplary embodiment,. ormed of Dlgital Electronic Cordless Telephone (DECT) systems. The microcellular networks 14 and 16 shall, at times, be referred to as DECT systems. In another embodiment, the networks 14 and 16 are alternatively formed of other types of Private Telephonic Networks (PTNs).

The macroceliular communication network 12 encompasses a macrocellular-region throughout which wireless communications by way of the network 12 are permitted. In conventional manner, the network 12 inclues a plurality of spaced-apart base stations, of which two base stations 18 are illustrated in the figure.

Each base station le encovpasses an area defining a cell 20. The cells 20 defined bv the base stations 18 collectively form the region encompassed by the network 12.

The base stations are coupled by way of base station controllers 22 to mobile services switching centers (MSCs), such as the mobile services switching centers 24 and 26. The base station controllers 22 are operable, inter alia, to control operation of the base stations 18 coupled thereto. Control operations, such as hand-off decisions and channel allocations, are performed at the controllers 22. Operation of the base station controllers 22, and the mobile services switching centers 24 and 26 of the exemplary embodiment corresponds generally with operation of such devices in existing standards specifications.

The mobile services switching centers 24 and 26 shown in the figure are inter-coupled, here indicated by the lines 28. The MSCs 24 and 26 are further coupled to a Public Switched Telephone Network (PSTN). Such couplings are illustrated by lines 32 and 34, respectively, in the figure.

The GSM network 12 further inclues location registers including the home location register (HLR) 36.

The HLR 36 is coupled to the MSCs 24 and 26 by way of lines 38 and 42, respectively. The KLR 36 is operable in the GSM communication network 12, inter alia, to perfore wide-area mobility management functions to facilitate call routing to and from mobile subscriber units operable to communicate by way of the communication network 12. Such mobility management functions inclue, for instance, ehe maintenance of a subscriber registry. The subscriber registry contais information relating to the subscriber obits whereabouts and statuts.

The HIR 36 is further coupled, by way of lines 44 and 46, respectively, to mobility servers 48 and 52 of the DECT systems 14 and l , respectively. In an exemplary ernbodiment, the mobility servers 48 and 52 are based on MD 110 hardware components. Services supported therefrom are developed on an Erlang platform. Services performed by the mobility servers 48 and 52 include those which are conventionally provided by mobility servers of conventional DECT systems.

The mobility server 48 is coupled to radio exchange equipment 54 by way of lines 56. The radio exchange equipment 54 inclues transceiver circuitry permitting communication with mobile subscriber units, such as the mobile subscriber unit 58. Similarly, the mobility server 52 is coupled to radio exchange equipment 62 by way of lines 64. Analogous to the radio exchange equipment 54, the radio exchange equipment 62 inclues transceiver circuitry permitting wireless communications with mobile subscriber units positioned within the area encompassed by the DECT system 16.

In one embodiment, the mobile subscriber unit 58 forms a dual-mode subscriber unit, selectively operable to communicate with both the GSM network 12 and the microcellular networks 14 and 16.

The mobility server 48 inclues a mobility manager 66 capable of communicating inf ormation with the HLR 36.

The mobility manager 66 is further coupled to a storage device 68 which also forms a portion ouf the mobility server 48. Similarly, the mobility server 52 inclues a mobility manager 72 which is capable of communicating information with the HLR 36. The mobility manager is further coupled to a storage device 74 which also fonts a portion of the mobility server 52. The mobility server 48 is further coupled to the MSC 24, here indicated by lines 76. And, the mobility server 52 is further coupled to the MSC 26, here indicated by the liners 78. Both the móbility servers 48 and 52 are further coupied to a PSTN and provide cnnventional call routing of calls between the PSTN and mobile subscriber units which are regularly registered in the respective communication networks 14 and 16.

The storage devices 68 and 74 store location information related to subscriber units operable in the respective networks associated with the mobility servers 48 and 52, respectively. As shall be described below, such location information can be updated during operation of an embodiment of the present invention. In one embodiment, the storage devices 68 and 74 further store service subscription information related to service subscriptions to which the subscriber units are subscribed.

During operation of an embodiment of the present invention, the wide-area mobility management functions provided by the GSM network 12 are further utilized by the DECT systems forming the microcellular networks 14 and 16.

Such utilization provides wide-area mobility to mobile subscriber units operable in the networks 14 and 16.

Thereby, communications with mobile subscriber units of the networks 14 and 16 are permitted when such subscriber units roam beyond the areas encompassed by the networks in which the subscriber units are regularly registered, viz., the subscriber units''home"network. For instance, when the mobile subscriber unit 58 roams beyond the microcellular network 14 and into, for instance, the microcellular network 16, the wide-area mobility management functions provided by the GSM network 12 are utilized to facilitate communications with the Zroamingb mobile subscriber unit. In an embodiment having dual-mode subscriber units, the wide-area mobility management functions provided by the GSM network are utilized by the subscriber units when comntunicating by way of the networks 14 and 16 and also when communicating by way of the GSM network 16.

Mobile application part (MAP) interfaces are introduced into the mobility servers 48 and 52, respectively. In one embodiment, *five MAP operations are supporte by the MAP interface. Namely, update location, insert subscriber data, delete subscriber data, cancel location, and provide roaming number operations are supporte by the MAP interface. Such operations are performed, as necessary, to permit communications with the subscriber unit when the subscriber unit roams beyond its home network.

Subscription information associated with mobile subscriber units, such as the subscriber unit 58, operable in the DECT network 14 are stored not only in the mobility server 48 but also in the HLR 36. Services pursuant to the subscription in the HLR 36, however, need not be defined. But, the subscriber unit 58 inclues an MSISDN number and an IMSI number allocated thereto. The subscription for the subscriber unit in the HLR 36 is based on such numbers.

The mobility servez 48 contains tables permitting transformation between a DECT identity, used to identify the subscriber unit in the DECT system 14 an the MSISDN and IMSI numbers, used to identify the subscriber unit in the GSM network 12.

The DECT identity, the IMSI, and the MSISDN allocated to the subscriber unit 58 are further defined in each mobility server, such as the mobility server 52, in each DECT system 16, or other PTN, in which the subscriber unit 58 is permitted to roam. Such information is predefined in the mobility servers. Such predefined information further inclues a predefined service profile which, in one embodiment, is not otherwise transEerred from the subscriber unit'58 home mobility server, here server 48, to a visited mobility server, here server 52. Each mobility server further inclues a series or roaming numbers which are defined in manners similar to the r6aming numbers defined in a mobile services switching center or location register of a conventional GSM network.

Signaling between the MSCs 24 and 26 and the HLR 36 is routed by using a global title (GT) and subsystem number (SSN). Thereby, the mobility servers 48 and 52 appear to the HLR 36 as mobile services switching centers, similar to the switching centers 24 and 26. The mobility servers further include unique MSC/VLR adresses, similar to the MSC/VLR addresses which identify the MSCs of the macrocellular network 12.

FIGURE 2 illustrates again the HLR 36 of the GSM network 12 and the mobility servers 48 and 52 of the DECT systems 14 and 16, respectively. Lines 44 and 46 are again shown to couple the M. R 36 with the mobility servers 48 and 52, respectively. And, the radio exchange equipment 54 and 62 are again shown to be coupled to the respective mobility serves 48 and 52. When a mobile subscriber unit, here subscriber unit 58, roams out of the microcellular network 14, its home network, and into the microcellular network 16, the subscriber unit 58 registers with the mobility server 52. The roaming of the subscriber unit is indicated in the figure by the arrow 84. The identity of the subscriber unit 58 in indexed against a list of subscriber units permitted to roam. A subscriber unit 58 is assumed to be listed on such list and a transformation between the DECT identity of the subscriber unit 58 and its corresponding IMSI nuiber is performed by the mobility manager 72.

Second, as indicated by the arrow 86, the mobility server 52 updates the location information of the subscriber unit with the EMJT 36. Then, and as indicated by the arrow 88, the HLR 36 provides the mobility server 52 with subscriber data, namely the INSU and MSISDN numbers, stored in the ELR 36. And, as indicated by the arrow 92, the HLR 36 causes the mobility server 48 to deregister the old registration of the subscriber unit 58 in the network 14. Thereby, the location of the subscriber unit 58 is updated to indicate its location in the area encompassed by the microcellular network 16, not the microcellular network 14.

FIGURE 3 illustrates operation of an embodiment of the present invention by which a call is routed to the subscriber unit 58, regularly registered at the network 14, when the subscriber unit 58 roams into the network 16..

Elements of the communication system 10 utilized in the exemplary operation of call routing to the roaming, subscriber unit 58 are shown in FIGURE 3 and identifie by the same reference numerals used to identify such elements in FIGURE 1.

When the mobility server 48 receives a call, such as a call originated at the PSTN to be terminated at the mobile subscriber unit, the identity ouf té subscriber unit is indexed against a list of subscriber units permitted to roam. The subscriber unit 58 is assumed to be on the list and marked as being roaming beyond the network 14. The mobility manager of the mobility server 48 translates the DECT identity of the subscriber unit into an MSISDN number, and the call is routed to the MSC 24, here forming a gateway MSC (GMSC). Such routing is indicated in the FIGURE by the arrow 102. Then, and as indicated by the arrow 104, the MSC 24 interrogates the HLR 36 for routing information to route the call to the roaming, subscriber unit.

Responsive to the interrogation, the HLR 36 requests a roaming I1X, MSRN, from the mobility server 52, as indicated by the arrow 106. The mobility server 52 returns the roaming number allocated to the subscriber unit 58 to the HLR 36, as indicated by the arrow 108. The HLR 36 thereafter, and as indicated by the arrow 112, returns the roaming number allocated to the subscriber unit SB to the MSC 24. Once the roaming number is received at the MSC 24, the call is routed to the roaming, subscriber unit 58, as indicated by the arrows 114, by utilizing the roaming number. The MSC 24, in one embodiment, generates both a transit call data record and a roaming call forwarding record, for billing purposes, if desired.

FIGURE 4 illustrates operation of an embodiment of the present invention by which the wide-area management functions provided by the GSM network 12 of the communication system 10 are utilized to facilitate routing of a call originated at a roaming subscriber unit, here subscriber unit 52 to a mobile subscriber unit operable in the GSM network. Again, elements of the communication system 10 utilized during such operation are identified with the same reference numerals utilized to identify such elements in FIGURE 1.

The subscriber unit 58 originates a call, indications of which are received by the radio exchange equipment 62.

The call request is provided to the mobility server 52 and the mobility manager 72 thereof indexes the identity of the roaming, subscriber unit against a listing of subscriber units permitted to roam. The subscriber unit is assumed to be on the list and the predefined service profile associated therewi. h is used for the subscriber unit 58.

The call is set up by way of the MSC 26, here forming a gateway MSC (GMSC) and the DECT identity of the subscriber unit 58 is used as an A-number. The cals vis thereafter routed, in conventional fashion pursuant to the GSM network, to be terminated at the mobile subscriber, here a mobile subscriber 122. That is to say, the MSC 26 interrogates the HLR, as indicated by the arrow 124, for routing information. Such routing information is received at the HLR 36 from the MSC 24, as indicated by the arrow 126, and a visited location register lnot shown) associated therewith. The routing information is provided to the MSC 26, as indicated by the arrow 128. Responsive to the routing information, the call is routed from the MSC 20-, to the MSC 24, as indicated by the arrow 130, and thereafter to the appropriate base station 18, as indicated by the arrow 132. The call is thereafter terminated at the mobile station 122, as indicated by the arrow 134.

FIGURE S illustrates oderation of an embod4-ment of the present invention whicn permits routing of a call originated by a roaming, subscriber unit, here subscriber unit 58, to another subscriber unit, here subscriber unit 136, positioned in another DECT network, here DECT network 14. The roaming, subscriber unit 58 generates a call to the subscriber unit 136. The identity of the subscriber unit 58 is indexed against a list of permitted roaming subscriber units. The subscriber unit 58 is assumed to be listed on the list, and a predefined profile is allocated to the subscriber unit. The identity of the subscriber unit 136 is also indexed against a list of permitted roaming, subscriber units. Hure, the subscriber unit 136 is assumed rut-tao be listed upon the list of subscriber units permitted to roam. The call is thereby routed as an ordinary call between two DECT networks.

FIGURE fi illustrates a communication system, shown generally at 200, of another embodiment of the présent invention. The communication systecn 200 is, analogous to the communication system 10 shown in FIGURE 1, a mXlti- network camunication sys. em, again including a macrocellular communication network 12 and at least two microcellular communicaXion networks, here communication networks 14 and 16. The networks 12, 14 and 16 include the same elements as those previously shown in FIGURW I.

Such corresponding elements are again identt Eied by the same reference numerals as those used in FIGURE 1.

Again, the macrocellular communication r~etwork 12 foras a GSM communication network having base stations 18, each ow which defìnes a cell 20. The base stations 18 are coupled via the base station controllers 22 to mobile services switching centers (MSCs), such as the MSC 24 and 26. The MSCs-24 and 26 are connecte together by way of lwnes 28.

The MSCs 24 and 26 are also coupled to a PSTN, here indicated by ray ouf lines 32 and 34, respectively. The MSCs 24 and 26 are further coupled to an HLR 3 6 hy way of lines 38 and 4z, respectively.

T.-. e network 14 inclues a mcbility sezver 48, and the network 16 includes a rnobility server 52. The mobility server 48 is coupled to radio exchange equipment 54 which inclues radio transceivers for communicating with mobile subscriber units, such as the mobile subscriber unit 58.

And, radio exchange equipment 62 is coupled to the mobility server 52 by way of lines 64.

The mobility server 48 is again shown to inclue a mobility manager 66 and a storage device 68. And, the mobility server 52 is agais shown to include a mobility manager 72 and a storage device 74. The mobility server 48 is coupled to the MSC 24 by way of lines 76, and the mobility server 52 is coupled to the MSC 26 by way of lines 78.

In the communication system 200, the HLR 36 is not directly coupled to the mobility servers 48 and 52.

Rather, the FILER 36 is indirectly coupled to the mobility servers by way of the Internet 242 which here forms an internet communication channel indirectly connecting the HLR 36 and the mobility servers 48 and 52. The Internet 242 forms a connection between the HLR 36 and the mobility serveurs.

The mobility server 48 is coupled, such as by way of a local area network (not shown in the figure) to a TCP mobile application part (TCP/MAP) 244. The TCP/MAP 244 encapsulates information to be transmitted to the HLR 36 according to an internet protocol (IP), or other appropriate protocol. Similarly, a TCP/MAP 246 encapsulates data to be transmitted to the mobility server 48 according to an internet protocol, or the li. ke. Tke TCP/MAP 244 is further operable to de-encapsulate information transmitted thereto. And, similarly, the TCP/MAP 246 is further operable to de-encapsulate infornation transmitted thereta. In like fashion, TCP/MAPs 288 and 2S2 encapsulate and de-encapsulate data to be trarsmi-tted between the HLR 36 and the mobility server 52 to permit its transmission by way of the internat 242. Because the internet permits communications to be eff-cLuated between the KLR wó and the mobility servers 48 and 52 without requiring that a direct connection be fonmed therebetween, security issues arising when an operator of the network 12 differs with the operator, or operators, of the networks 14 and 16 are avoided. Direct signaling, such as CCITT 7 signaling, is not required to effectuate communication of information needed to provide the networks 14 and 16 with the widearea mobility functions of the network 12.

Operation of the present invention permits wide-area mobility management functions provided by a macrocellular communication network to be utilized by a microcellular communication network to facilitate communication with a mobile subscriber. A mobile subscriber regularly registered in one microcellular communication network can roam to another microcellular communication network and utilize the wide-area mobility permitted in a macrocellular communication network to route calls to the roaming, subscriber unit.

The previous descriptions are preferred examples-for implementing the invention, and the scope of the invention should not necessarily be limited by this description. The scope cf the present invention is defined by the following claims.

Claims (8)

CLAIMS:

1. In a communication system having a macrocellular network and at least a first microcellular network, an improvement of apparats for permitting communication between the macrocellular network and the microcellular network, said apparats comprising: a first signaling device coupled to the microcellular network, the first signaling device for encapsulating microcellular-generated data into Internet protocol data ; a second signaling device coupled to the macrocellular network, the second signaling device for de-encapsulating the Internet protocol data, when received thereat ; and an Internet communication channel formed between said first signaling device and said second signaling device, said Internet communication channel forming a communication path between said first signaling device and said second signaling device, thereby to permit the communication between the macrocellular network and the microcellular network.

2. The apparats of claim 1 wherein said second signaling device further encapsulates macrocellulargenerated data into the Internet protocol data and wherein said first signaling device further deencapsulates the Internet protocol, when received thereat.

3. In a communication system having a macrocellular network and at least a first microcellular network, an improvement of apparats for permitting communication between the macrocellular network and the microcellular network, said apparats comprising: an encapsulator for encapsulating macrocellular-generated data into Internet protocol data, the Internet protocol data of Internet-channeltransmissible characteristics.

4. The apparats of claim 3 further comprising a de-encapsulator for de-encapsulating encapsulated, microcellular-generated data transmitted thereto, the encapsulated, microcellular-generated data of Internetchannel-transmissible characteristics.

S. In a communication system having a macrocellular network and at least a first microcellular network, an improvement of apparats for permitting communication between the macrocellular network and the microcellular network, said apparats comprising: an encapsulator for encapsulating microcellular-generated data into Internet protocol data, the Internet protocol data of Internet-channeltransmissible characteristics.

6. The apparats of claim 5 further comprising a de-encapsulator for de-encapsulating encapsulated, macrocellular-generated data transmitted thereto, the encapsulated, macrocellular-generated data of Internetchannel-transmissible characteristics.

7. In a method for communicating in a communication system having a macrocellular network and at least a first microcellular network, an improvement of a method for facilitating communication between the macrocellular network and the microcellular network, said method comprising the steps of : encapsulating microcellular-generated data into microcellular-Internet protocol data ; transmitting the microcellular-Internet protocol data upon an Internet communication channel to the macrocellular network ; de-encapsulating the microcellular-Internet protocol data once the microcellular-Internet protocol data is received at the macrocellular network.

8. The method of claim 7 comprising the further steps of : encapsulating macrocellular-generated data into macrocellular-Internet protocol data ; transmitting the macrocellular-Internet protocol data upon the Internet communication channel to the microcellular network ; de-encapsulating the macrocellular-Internet protocol data once the macrocellular-Internet protocol data is received at the microcellular network.