(12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)
`
`(19) World Intellectual Property Organization
`International Bureau
`
`(43) International Publication Date
`11 October 2001 (11.10.2001)
`
` (10) International Publication Number
`
`WO 01/76154 A2
`
`(51) International Patent Classification’:
`29/06, 12/66
`
`HO4L 12/56,
`
`(21) International Application Number:
`
`=PCT/CA01/00377
`
`(22) International Filing Date:
`
`27 March 2001 (27.03.2001)
`
`(25) Filing Language:
`
`(26) Publication Language:
`
`English
`
`English
`
`(74) Agents: BEAUCHESNE,Sandraet al.; Ericsson Canada
`Inc., 8400 Decarie Boulevard, Town of Mount Royal,
`Québec H4P 2N2 (CA).
`
`(81) Designated States (national): AL, AG, AL, AM, AT, AU,
`AZ, BA, BB, BG,BR, BY, BZ, CA, CH, CN, CO, CR, CU,
`CZ, DE, DK, DM,DZ, EE, ES, FI, GB, GD, GE, GH, GM,
`HR, HU,ID,IL, IN,IS, JP, KE, KG, KP, KR, KZ, LC, LK,
`LR, LS, LT, LU, LV, MA, MD, MG, MK, MN, MW, Mx,
`MZ, NO, NZ, PL, PT, RO, RU, SD, SE, SG, SI, SK, SL,
`TJ, TM, TR, TT, TZ, UA, UG, US, UZ, VN, YU, ZA, ZW.
`
`(30) Priority Data:
`09/541 ,529
`
`(84) Designated States (regional): ARIPO patent (GH, GM,
`KE, LS, MW, MZ, SD, SL, SZ, TZ, UG, ZW), Eurasian
`patent (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), European
`(71) Applicant (for all designated States except US): TELE-
`patent (AT, BE, CII, CY, DE, DK, ES, FI, FR, GB, GR,IE,
`FONAKTIEBOLAGET LM_ERICSSON=(publ)
`
`[SE/SE]; $-126 25 Stockholm (SE).
`IT, LU, MC, NL, PT, SE, TR), OAPI patent (BF, BJ, CF,
`CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG).
`
`3 April 2000 (03.04.2000)
`
`US
`
`(72) Inventor; and
`(75) Inventor/Applicant (for US only): MARCHAND,Lau-
`rent [CA/CA]; 1656 Place Victor-Hugo, Montreal, Québec
`H3C 4N9 (CA).
`
`Published:
`without international search report and to be republished
`upon receipt of that report
`
`[Continued on next page]
`
`(54) Title: AD-HOC NETWORK AND GATEWAY
`
`35
`
`3G WIRELESS
`IP NETWORK
`
`
`
`O01/76154A2
`
`
`
`BLUETOOTH/IP/JINI
`AD-HOC NETWORK
`
`34
`
`(57) Abstract: A Bluetooth Piconet (30) includes a plurality of devices (31-33) having Bluetooth chipsets that are linked by a Blue-
`tooth radio link. The Piconet is extended into an Internet Protocol (IP) wireless LAN (35) in orderto utilize JINI technology for the
`sharing of services between devices in the Piconet. A Lookup Service (22) is implemented to make services available to the plurality
`of devices in the Piconet. A mobile phone (33) is configured as a gateway that providesa call-control interface between the wireless
`IP network (35) and the devices in the Piconet(30).
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`—_IMINIIMTUININOTAIATIAA
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`For two-letter codes and other abbreviations, refer to the "Guid-
`ance Notes on Codes andAbbreviations" appearing at the begin-
`ning ofeach regularissue ofthe PCT Gazette.
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`AD-HOC NETWORK AND GATEWAY
`
`BACKGROUNDOFTHE INVENTION
`
`Technical Field of the Invention
`
`This inventionrelates to telecommunication systems and, moreparticularly,
`
`to an ad-hoc network and a gateway that provides an interface between external
`
`wireless IP networks and devices in the ad-hoc network.
`
`Description of Related Art
`Around the world, people are connecting more than ever. Cellular phones,
`personal digital assistants (PDAs), and Internet-enabled computers are commonplace
`
`in both businesses and homes. Even where a formal networkis not recognized, users
`
`want their devices to communicate, and they wanteasy accessto the services made
`possible by network technology. For example, there are networks in the home
`
`connecting audio/visual equipment suchastelevisions and stereo equipment to home
`
`15
`
`office computers. There are also devices to control networks such as security
`
`surveillance systems and temperature-control thermostats.
`
`A problem arises in today's environmentbecausetraditional networks are much
`
`too complex to set up, expand, and manage. For example, adding hardware or
`
`software to an office environment usually requires a network administrator to load
`
`20
`
`drivers and configure systems. Even in a home environment, connectingall of the
`
`_ components of a homeentertainment system can be a daunting task for the average
`
`consumer. Networks todayare also too brittle and inflexible. A slight change in a
`
`network can cause havocthat can be extremely difficult to fix. From the consumer's
`
`perspective, what is needed is a simple way to connectdigital devices into impromptu,
`
`25
`
`expandable networks for immediate access to a wide variety ofservices.
`
`New technologies are being developed to makeit easier to network multiple
`
`devices. Bluetooth, for example, is a wireless communication technology for data and
`voice. It is based on a low-cost short-range radio link that operates in the unlicensed
`ISM band at 2.4 GHz. Bluetooth is a layer 1 (physical layer) and layer 2 (data link
`
`30
`
`layer) technology that allows one universal short-range radio link to replace many
`
`proprietary cables that are currently required to connect one device to another. The
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`physical layer provides transmissionofsignals and the activation and deactivation of
`
`physical connections, while the data link layer may include signal synchronization,
`
`error correction, sequencing, and flow control. This layer may also provide a data
`
`transmission link across one or several physical connections. Bluetooth, however,
`
`does not have any knowledge of the upper level network, transport, session, or
`
`application layers.
`
`The Bluetooth wireless technology allows users to makeeffortless, wireless,
`
`and instant connections between various communication devices such as mobile
`
`phones and desktop and laptop computers. Transfer of both voice and datais real-
`
`time, and the transmission mode provides security of data and protection from
`
`interference. A small chipset 1s utilized to implement Bluetooth radio technology in
`
`a communication device. Two powerlevels are provided, a lower powerlevelthat is
`
`sufficient to cover the area within a single room, and a higher powerlevel that can
`cover a medium range such as withina home. Each chipset includes software controls
`and identity coding that ensure that only those devices preset by the user can
`
`15
`
`communicate overthe radio link.
`
`A Piconet consists of a collection of devices connected via Bluetooth
`
`technology in an ad-hoc fashion. A Piconet may comprise as few as two connected
`
`devices, such as a computer and a printer, and may comprise as many as eight
`
`20
`
`connected devices (a “master” device and seven “slave” devices). Both point-to-point
`
`and point-to-multipoint connections are supported. Whenfirst establishing a Piconet,
`
`one deviceacts as a master andthe other devices act as slaves for the duration ofthe
`
`Piconet network establishment. Thereafter, the devices behave as peer units. All
`
`devices in the same Piconet havepriority synchronization, but other devices can be set
`
`25
`
`to enter at any time. Multiple independent and non-synchronized Piconets form a
`
`Scatternet.
`
`A JINI system is a Java-technology-centered, distributed software system
`
`designed for simplicity, flexibility, and federation. The JINI architecture provides
`
`30
`
`mechanisms for machinesor programsto enter into a federation where each machine
`or program offers resourcesto other membersofthe federation and uses resourcesas
`needed. The design of the JINI architecture exploits the ability to move Java
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`programminglanguage code from machine to machine,andit unifies, under the notion
`of a service, the user, the software, and the hardware components of the machines
`themselves.
`,
`
`JINI connection technology simplifies
`
`the processes of establishing,
`
`configuring, and controlling a network. From theuser's perspective, JINI technology
`
`makes connecting to new levels of services as simple as turning on a light switch.
`From thetraditionalservice provider's perspective, JINI connection software simplifies
`delivery and managementof services. When a PC connects to a Local Area Network
`
`(LAN), for example, it uses an IP multicast mechanism to find a server. The server
`
`10
`
`then assignsan IP addressto the PC and providesthe address ofa JINI Lookup Service
`(LUS). The LUS containsa list ofavailable services provided by other devices on the
`network. The LUSis also used by the PC to publish the services that it can provide
`
`to other devices on the network. Services are invoked by transferring a small amount
`
`of code written, for example, in Java code. Devices announcenot only value-added
`
`services, but also their attributes and capabilities to the network. JINI technology
`
`“communities” are resilient, and adapt very quickly to changes as users come and go.
`
`The Session Initiation Protocol (SIP) is an application-layer control protocol
`
`that can establish, modify, and terminate sessions or calls. These multimedia sessions
`
`20
`
`include multimedia conferences, distance learning, Internet telephony, and similar
`applications. H.323 is anothercall control protocol for IP telephony defined by the
`International] Telecommunications Union (ITU).
`
`Utilizing existing technologies, the following scenario can be realized. A user
`creates an ad hoc network based on Bluetooth technology (i.e., a Bluetooth Piconet).
`There are three Bluetooth devicesin the Piconet: a third generation Internet Protocol
`
`25
`
`(3G IP) mobile telephone, a Personal Digital Assistant (PDA), and a multimedialaptop
`
`computer. The mobile phoneis the masterunit, and the PDA andlaptopare slaves to
`
`the mobile phone. Neither the PDAnorthe laptop have a cellular radio modem orcall
`
`control client software (H.323or SIP) installed. Thus, neither the PDA northe laptop
`
`know anything about the cellular IP network. Therefore, a problem arises when the
`
`30
`
`user wantsto establish a videocall from hislaptop.
`
`Today,the only wayto solve this problem is to insure that each device contains
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`a cellular radio modem,a Bluetooth chipset, and a cal! control client. Bluetooth radio
`
`units and baseband are very inexpensive when comparedto cellular radio modems.
`
`Consequently,it is inappropriate, expensive, and cumbersometo instal] a cellular radio
`
`modem in every device in the Bluetooth Piconet. Furthermore, loading the rightcall
`
`contro] mechanism (H.323 or SIP client) into a PDA orlaptop requiresthe user to have
`
`a higherlevel of technical knowledge regarding the characteristics of the 3G wireless
`
`Internet network.
`
`Additionally,it is inefficient from the resource point ofview to require loading
`
`a call control client such as H.323 (about 4 MB) in multiple devices on the Piconet.
`
`Moreover, even if every device had its own cellular radio modem and call control
`
`client, the IP address scheme in the Piconet will certainly be different than the
`
`addressing scheme as currently used in wireless IP networks such as the General
`
`Packet Radio Service (GPRS).
`
`There are no known priorart teachings of a solution to the deficiencies and
`
`shortcomings discussed above. It would be advantageous,therefore, to have an ad-hoc
`networkthat can beefficiently, easily, and inexpensively established for a plurality of
`
`devices, and a gateway that provides access through the ad-hoc network to external
`
`wireless IP networks. The present invention provides such a network and gateway.
`
`10
`
`15
`
`20
`
`SUMMARYOFTHE INVENTION
`
`25
`
`In one aspect, the present invention is a gateway for an ad-hoc network that
`
`provides a call-control interface between an external wireless Internet Protocol(IP)
`network and devices in the ad-hoc network. The gateway includes a first interface
`
`toward the ad-hoc networkthat establishes the gateway as a call-control server for
`
`client devices in the ad-hoc network, and a second interface toward the wireless IP
`network that establishes the gatewayas a call-controlclient for a server in the wireless
`IP network. The ad-hoc network may be a Bluetooth Piconet, and the gatewayis
`preferably implemented in a mobile phone. Thefirst interface may include a private
`
`IP address recognized in the Piconet while the second interface mayinclude a public
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`30
`
`IP address recognized in the wireless IP network.
`
`In another aspect, the present invention is a Bluetooth Piconet comprising a
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`plurality of devices having Bluetooth chipsets, the devices being linked by a wireless
`
`IP network based on Bluetooth technology. The Piconet also includes a JINI Lookup
`
`Service (LUS) for makingservices available to the plurality of devices in the Piconet,
`
`and a gateway which may be implemented in a mobile phone that providesa call-
`
`control interface between an external wireless IP network and the devices in the
`
`Piconet.
`
`In anotheraspect, the present invention is an integrated network comprising a
`
`wireless IP network and a Bluetooth Piconet. The wireless IP network includesa call-
`
`control server and a Home Subscriber Server (HSS)that stores location information
`
`for mobile subscribers, and stores bearer capabilities and application capabilities for
`
`IP devices registered with the network. The Bluetooth Piconet includesaplurality of
`
`devices having Bluetooth chipsets that are linked by a Bluetooth radio link. The
`Piconet also includes a JINI LUS for making services available to the plurality of
`devices in the Piconet, and a gatewaythat providesa ca]]-control interface between the
`
`wireless IP network and the devices in the Piconet.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The invention will be better understood and its numerous objects and
`
`advantages will become more apparentto those skilled in the art by reference to the
`
`20
`
`following drawings, in conjunction with the accompanying specification, in which:
`
`FIG. 1 (Prior Art) is an illustrative drawing of an existing Bluetooth ad-hoc
`
`network;
`
`FIG.2 is an illustrative drawing illustrating a protocol stack for a Bluetooth
`
`Piconet that has been extended into an IP wireless LAN implementing JINI and Java
`
`25
`
`technologies in accordance with the teachings of the present invention;
`FIG.3 is an illustrative drawing ofan ad-hoc networkutilizing Bluetooth, IP,
`and JINI technologies in accordance with the teachings of the present invention to
`
`enable the use of a gateway mobile phone; and
`
`FIG. 4 is a simplified functional block diagram of a connection between a
`
`30
`
`laptop computer and a mobile phoneutilizing the ad-hoc networkofFIG.3.
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`DETAILED DESCRIPTION OF EMBODIMENTS
`
`The present invention relies on several technologies. First, a wireless IP
`
`networkis established between devices utilizing Bluetooth technology. Then, JINI
`
`(Java) technology is utilized to publish and share services betweenthe devices, and to
`establish a client/serverrelationship betweenthe devices and one ofthe devices having
`
`acellular radio modem andacall control chent. Finally SIP and/or H.323are utilized
`
`to implementthe call control client. The use of SIP is preferred, but the invention may
`
`utilize H.323 technology as well.
`
`FIG. 1 is an illustrative drawing of an existing Bluetooth ad-hoc network 10.
`
`10
`
`A laptop computer 11, a printer 12, and an office telephone 13 are each equipped with
`
`a Bluetooth chipset that enables them to communicate over the Bluetooth radio link
`
`14. The office phone must contain an H.323 or SIP client connected via Asychronous
`
`Digital Subscriber Line (ADSL) or cable modem.
`FIG.2 is an illustrative drawingillustrating a protocol stack for a Bluetooth —
`
`15
`
`Piconet that has been extended into an IP wireless LAN implementing JINI and Java
`
`technologies in accordance with the teachings of the present invention. The layers
`
`include a physical layer 15 andalink layer 16 which, together, are provided in the
`
`present invention by the Bluetooth Piconet. On topofthat, a network transport layer
`17 is implemented using the Internet Protocol (IP). After an operating system layer
`
`20 ©
`
`18, a Java technology layer 19 and a JINI technology layer 20 implement the JINI
`
`technology providing the capability for an application 21 to discover, join, and
`
`downloadservices 22 from a JINI LUS.
`
`In the present invention, a mobile phoneis equipped with a Bluetooth chipset.
`Thus, the mobile phone can simultaneously be connected to a cellular network and to
`an ad-hoc Buletooth Piconet. Additionally, the Piconet is extendedinto an IP wireless
`
`25
`
`LANinorderto utilize JINI technology for the sharing of services between devicesin
`
`the Piconet. Moreover,
`
`the mobile phone includes an interface/Application
`
`Programming Interface (API) which is an abstraction of a SIP and/or H.323 call
`
`controlclient. Just prior to execution, this API is downloadedto the Bluetooth device
`
`30
`
`involved in an external wireless call in order to have the device behave as a slave —
`
`device toward the mobile phone which is the master. The API is downloaded only to
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`the device involved in the call since the other Bluetooth devices that are not making
`
`the call do notneed this particular code. The present invention also anticipates the fact
`
`that many consumerproducts will be modified to provide multimedia and telephony
`
`for example, will soon contain
`capabilities. Multimedia laptop computers,
`microphones,speakers, and video cameras. PDAswill also have similar features and
`
`potentially act as hands-free phones, etc.
`
`FIG.3 is an illustrative drawing of an ad-hoc network30 utilizing Bluetooth,
`
`IP, and JINI technologies in accordance with the teachings of the present invention to
`
`enable the use of a gateway mobile phone. A laptop computer 31, printer 32, and
`
`mobile phone 33 are all Bluetooth-compliant and JINI/Java-capable, enabling JINI
`
`APIs to be transported between the devicesutilizing the Bluetooth radio link 34.
`
`Thepresent invention positions the mobile phone 33 as a gateway between the
`
`ad-hoc network and a 3G wireless IP network 35 such as the General Packet Radio
`
`Service (GPRS) network. The mobile phone receives IP packets from the GPRS
`
`15
`
`networkthroughits public IP address, and forwardsthe received packets to the private
`
`‘IP address of the destination device in the Piconet.
`
`It also translates in the other
`
`direction for data going out of the Piconet to the GPRS network. With this invention,
`
`‘any Bluetooth-compliant device in a Piconet that is multimedia capable is able to
`
`establish a call as long as one of the devices in the Piconet(e.g., the mobile phone)
`
`20
`contains a cellular radio modem andacall control client, and is connected to the
`
`wireless IP network. The cellular radio modem maybe, for example, a Wideband
`Code Division Multiple Access (WCDMA) modem, an EDGEradio access modem,
`or equivalent. Any Bluetooth-compliant device entering into the Piconetutilizes JINI
`
`technology in order to discover and publish lookup services that the device can receive
`
`25
`
`or offer to other devices in the Piconet.
`
`FIG.4 is a simplified functional block diagram of a connection between two
`
`devices such as the laptop computer 3 land the mobile phone 33 utilizing the ad-hoc
`
`network 30 of FIG. 3. The present invention establishes three new interfaces or
`
`Application ProgrammingInterfaces (APIs) between the slave device placing thecall
`
`30
`
`and the master mobile phone, and enhances the H.323 and/or SIP clients in the mobile
`
`phoneto act as a server application. The interfaces are preferably implementedas JINI
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`services. The first interface/APIis an abstraction of a SIP and/or H.323 call control
`
`client 41. This interface enables any ofthe Bluetooth devices on the Piconet to behave
`
`as a slave device toward the mobile phone which is the master. This allows the
`
`establishment of voice calls in a simple fashion regardless of the. call control
`
`mechanism supported in the mobile phone or network. The secondinterface/APIis
`
`a SIP client 42 which enables the use of the full SIP client capabilities. The SIP client
`
`interfaces via SIP signaling with a SIP proxyserver43 in the 3G wireless IP network.
`
`The third interface/API is an H.323 client 44 which enablesthe use ofthe full H.323
`
`client capabilities. The H.323 client interfaces via H.323 signaling with an H.323
`
`10
`
`gatekeeper 45.
`
`_ Utilizing the JINI Lookup Service (LUS) 46, the gateway mobile phone 33
`
`must "publish" in the Bluetooth Piconet, the call control services that it offers. The
`
`other Bluetooth devices on the Piconet perform an add-in protocol called “discovery
`
`15
`
`and join”to locate the LUS and uploadall ofits services’ interfaces, including the call
`control services. The H.323 and/or SIP clients in the mobile phone are enhanced to
`behaveas a server application in order for Bluetooth compliant devicesto talk to other
`
`devices that contain a SIP and/or an H.323 client.
`
`In addition to defining a set of protocols for discovery, join, and lookup, JINI
`
`technology also definesa leasing and transaction mechanism to provide resiliencein
`
`20
`
`a dynamic networked environment. The technology and services architecture is
`
`powerful enough to support a fully distributed system on a network of workstations,
`
`while small enough to build a community of devices out of simple devices such as
`
`homeentertainment devices or mobile phones.
`Devices in a network employing JINI technology may be tied together using
`Java Remote MethadInvocation (RMI). By using the Java programming language,
`a JINI connection architecture is secure. The discovery andjoin protocols, as well as
`the lookup service depend onthe ability to move Java objects, including their code,
`
`between Java virtual machines.
`
`Alternatively, JINI call control APIs may be transmitted to and from the call
`control server in the mobile phone with the Internet Inter-ORB Protocol (IOP). An
`ORB is an Object Request Broker utilized in the Common Object Request Broker
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`
`Architecture (CORBA).
`
`CORBA is a strategy, a set of specifications, an
`
`infrastructure, and a set oftools that enables reusable programmingobjects to be used
`
`by manyapplications in a platform-independent manner. The architecture provides
`
`general services and request and response capabilities at a low level, independent of
`
`theupper level architecture. The distribution of a variety of programming languages
`is supported.
`.
`
`Fixed telecommunications protocols such as ANSI-41 or SS7 have a problem
`
`when a new parameter is added to an existing message, or a new message is added
`
`because existing applications maynot be able to handle the changes. The applications
`
`then do not work when a nodein the network is updated with the latest revision of the
`
`protocol. As noted above, the present invention overcomesthis problem by using a
`
`solution that is more closely aligned with the approach developed by the computer
`
`industry. The solution is more API-centric in that, rather than defining a large set of
`protocols, an API is published toward an application, and the application uses the API
`as a client. Of course, the API, which may be a small piece of Java code, is
`
`transmitted as messages over the wire; but rather than having a large number of
`
`distinct messages, the present invention usesa call control client such as a SIP client
`in the mobile phonethat can only generatea few generic messagessuch as Get, Send,
`Receive,etc.
`
`20
`
`In the present invention,a JINI call control API 47is published by the mobile
`
`phone 33 and enables the applications 21 in the laptop and other devicesin the Piconet
`
`to make use ofthe facilities of, for example, the SIP client 42 in the mobile phone.
`
`The JINIcall control API is an abstraction of both SIP and H.323sinceatthis timeit
`
`is not known whetherSIP or H.323 will be the accepted standard. Once a standardis
`
`25
`
`determined, the API may be constructed as an abstraction of one or the other, or an
`
`equivalent call control protocol.
`
`©
`
`Assumingthat the preferred standard is SIP, whenthe user desires to send a
`
`call, he is actually instructing the mobile phone to send a SIP INVITE message, which
`
`is the initial SIP messageto establish a call. The mobile phone, regardless of whether
`
`30
`
`it supports SIP or H.323 generatesthe right sequence of messagesto SIP the call. This
`
`approachis substantially simpler than the direct utilization of these protocols, and it
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`decouplesall the applications from the underlying infrastructure.
`
`Manyuseful networkactivities are possible with the network architecture of
`the present invention. For example, a user with a Bluetooth-compliant mobile phone
`
`may walk into a room that has a printer and a laptop computer, both of whicharealso
`
`Bluetooth-compliant. However, in this example,there is no WCDMAor EDGEradio
`
`access modem inthe laptop. Regardlessofthis fact, with the present invention, he can
`
`still print a file from the laptop onthe printer, and canalsoestablish a voice or video
`
`call from the laptop. Today, the user would have to purchase a SIP client and install
`
`10
`
`the SIP client in the laptop in order to do so. Sinceinstalling the SIP client involves
`configuring the laptop to get a static or dynamic IP address, and many other
`specialized tasks, it is beyond the capability of most consumers.
`In the present invention,the laptop uses the mobile phoneas a gateway toward
`
`the wireless IP network. When all these Bluetooth devices are located within
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`approximately 10 meters of each otherfor a low power Bluetooth Piconet, or within
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`approximately 100 meters of each other for a high power Bluetooth Piconet, the
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`mobile phone connects to the Bluetooth Piconet as well as to the wireless network.
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`Atthat point,all of the devices on the Piconet publish the services they can provide
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`to the other devices through the JINI LUS. Ifa visitor with a communication device
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`such as a PDA comesto the office location and wants to send somee-mail, but does
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`not have a connection, he mayregister with the Piconet and use the call control client
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`that the host’s mobile phoneis providing. He can then send and receive his e-mail
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`through the host’s mobile phone. A password maybe required to accessthe services
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`available in the Piconet.
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`The services menuon the laptop indicatesall services available on the Piconet.
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`Whentheuserplacesa call from the laptop, the SIP client in the mobile phone sends
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`an API to the laptop that is used to route the call through the mobile phoneto the
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`wireless IP network. The SIP client in the mobile phone behaves as a server
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`application for the Piconet, and another API is downloadedto the laptop in order to
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`connect to the server. The phoneacts as a server application toward the laptop, and
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`acts as a client and gateway toward the wireless IP network.
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`In the preferred embodiment, the mobile phone has twoIP addresses: a public
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`IP address recognized by the wireless IP network such as an external GPRSnetwork,
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`and a private IP address recognized by the other devices on the Piconet. The use of
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`private IP addresses on the Piconet is beneficial in two ways. First, security is
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`enhanced on the Piconet since outside entities do not know the private IP address of
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`each device and therefore cannot gain direct access to those devices. Second, the use
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`ofprivate IP addresses helps with the problem of the depletion of public IP address.
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`The mobile phone has a radio access modem and a Bluetooth chipset,so it has
`two interfaces. The two physical interfaces may appear with the samelogical IP
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`address, butthis is not preferred since the other Bluetooth devices would then require
`public IP addresses as well.
`In the wireless IP network 35,the existence ofthe laptop 31 is not known. The
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`only IP address that is knownis the public IP address of the mobile phone 33 which
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`is published in the wireless IP network. Al] incoming IP packets toward the mobile
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`phonethat are targeted toward the laptop application 21 are received on the public IP
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`address of the mobile phone and are then pushed to the private IP address of the
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`appropriate device (the laptop) on the Bluetooth Piconet.
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`Several potential problems involving public and private IP addresses are
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`resolved by the API that is sent from the SIP client in the mobile phoneto the laptop.
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`First, the use of private IP addresses in public IP networks can cause problemssince
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`the assignmentofprivate IP addresses is not controlled at a higherlevel, and duplicate
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`private IP addresses can be assignedto different parties. In the present invention, the
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`public IP address of the mobile phone is used for communications in the public
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`network. An additional problem mayarise if a National Access Translator (NAT),as
`proposed by the Internet Engineering Task Force (IETF), is used in an attempt to
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`overcomethe problem ofduplicate private IP addresses. The NAT device temporarily
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`provides a networked device with a global public IP address when the device desires
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`to communicate outside of its private network. However, in real-time applications
`such as Voice-over-IP (VoIP), the IP addresses of the parties are contained in the
`payload itself in addition to the packet headers. The situation mayarise, therefore,
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`when the NAT device changes the source IP address in the header to a temporary
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`public IP address, but the payloadstill identifies the source IP addressasthe private
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`IP address. Thus, there ts an IP address mismatch that creates problems forreal-time
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`applications such as VoIP.
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`In the present invention, the API ensures that this
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`mismatch does not occur.
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`The inventionis not limited to wireless office applications, but has many other
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`potential uses. For example, a user may have a Bluetooth-compliant screen phonein
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`his house, and the phoneis connected to a cable modem. When heenters his house
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`with his Bluetooth-compliant mobile phone, the mobile phone recognizesthat there
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`is already a Bluetooth device on the Piconet that enables the user to place calls. The
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`mobile phone maythen disconnect from the external wireless network while remaining
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`connected to the Bluetooth Piconet. Thereafter, if the user places a call with his
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`mobile phone from within his house, the mobile phone behavesas a cordless phone
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`that is linked to the screen phoneas a base unit. Therefore, the call goes through the
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`screen phonethat is connected to the cable or DSL modem. Thus, the Piconet enables
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`the call to be placed in the most cost-effective manner. Upon exiting the house, the
`mobile phoneloses the Bluetooth connection and re-connectsto the external wireless
`network.
`The mobile phone may connect to multiple independent Piconets since each
`Piconetis limited to eight devices on the network. This configuration requiresthat the
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`mobile phoneutilize a different IP address for each Piconet. Due to the problem ofthe
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`depletion of public IP addresses, these addresses are preferably private IP addresses,
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`althoughthis is not required.
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`The present invention also provides a sending device with the capability to
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`determine the terminalclass and terminal configuration (i.e., bearer capability and
`application capability) ofthe target device. The sending device can then intelligently
`selectthe correct targetdevice to receive a particular application. Forexample, if a
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`first user wants to send both voice and color video to a second user, the connection
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`should not be made to a mobile phone which may only have a 2-line, non-color
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`display. If a multimedia laptop computer is also connectedonaPiconet with the
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`mobile phone,the call should be directed to the laptop instead.
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`In 3G wireless IP networks,
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`the Home Location Register (HLR) 48 is
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`complemented by a Home Subscriber Server (HSS) 49. The HSS addscapabilities to
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`the location register and subscriber database in the HLR making it an IETF
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`Authorization, Authentication, and Accounting (AAA) Server.
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`In the present
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`invention, each timethe user ofthe Piconetregisters an IP device with the Piconet, the
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`terminal class and terminal configuration (bearer capability and the application
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`capability of the IP device) are passed to the HSS. The application capability
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`indicates, for example, whether the device is a 1/4-VGAscreen or a laptop with full
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`VGAscreen, etc. When a party calls the mobile phone which is registered in the
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`Bluetooth Piconet, the HSS returns the public IP address of the mobile phoneto the
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`caller along with an indication ofthe terminal classes and terminal configurations of
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`the devices on the Piconet. The caller can then pick the device ahead of time that
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`makes sense fo