(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2002/0065065 A1
`
`Lunsford et al.
`(43) Pub. Date:
`May 30, 2002
`
`US 20020065065A1
`
`(54) METHOD AND SYSTEM FOR APPLYING
`LINE OF SIGHT IR SELECTION OFA
`RECEIVER TO IMPLEMENT SECURE
`TRANSMISSION OF DATA TO A MOBILE
`COMPUTING DEVICE VIAAN RF LINK
`
`(76)
`
`Inventors: E. Michael Lunsford, San Carlos, CA
`(US); Stove Parker, Centerville, UT
`(US); David Kammer, Seattle, WA
`(US); David Moore, Riverton, UT (US)
`
`Correspondence Address:
`WAGNER, MURABITO & HAO LLP
`Two North Market Street
`Third Floor
`San Jose, CA 95113 (US)
`
`(21) Appl. No.:
`
`09/727,983
`
`(22)
`
`Filed:
`
`Nov. 30, 2000
`
`Publication Classification
`
`....... H04Q 7/00
`Int. Cl.7 ......
`(51)
`
`
`455/500; 455/556
`(52) US. Cl.
`...........................
`
`ABSTRACT
`(57)
`A Wireless communication method for secure transmission
`
`of data between mobile computing devices. The method
`includes the step of transmitting a line of sight beam from a
`first device to a second device to mutually identify the first
`device and the second device out of a plurality of devices.
`Once identified, the first and second devices establish an RF
`communications link between the identified first device and
`the identified second device. Using the RF communications
`link, the data transfer is then performed between the first
`device and the second device. The line of sight beam to
`select a secure transmission method for the RF communi—
`cations link can be an IR communications beam. The RF
`communications link can be a secure RF communications
`link recognizable only by the first and second devices output
`of the plurality of devices. The RF communications link can
`be compatible with a version of the Bluetooth specification.
`The secure transmission method can be an encryption
`method for the RF communications link. At least one of the
`first and second mobile computing device can be a PlD
`(personal information device). At least one of the first and
`second mobile computing devices can be a cellular tele-
`phone. Upon completion of the data transfer, a confirmation
`can be presented to the user.
`
`TODISPLAY
`
`DISPLAY
`INPUT
`12.
`
`DISPLAY
`OUTPUT
`fl
`
`‘
`
`USER INTERFACE
`'
`ClRCIJlTRY
`1Q
`
`.
`
`PROCESSOR / CONTROLLER
`.
`29.
`
`IKDA
`
`.
`
`RF
`
`.
`
`.
`
`STACK
`
`MEMORY 4_o
`REMOTE CONTROL
`LOADING APPLICATION
`
`DATA STORAGE
`. 8 -
`'
`
`12
`
`APPLE 1010
`
`APPLE 1010
`
`1
`
`

`

`Patent Application Publication May 30, 2002 Sheet 1 0f 7
`
`US 2002/0065065 A1
`
`r’
`
`\O p
`
`PID
`
`FIG;1
`
`2
`
`

`

`Patent Application Publication May 30, 2002
`
`Sheet 2 0f 7
`
`US 2002/0065065 A1
`
`
`
`JOZEOOmFOSNE
`
`
`
`zDF<o§mm<02.30..
`
`Mm
`
`@5652
`
`
`
`mo<m0._.w<._.<D
`
`>Snma
`
`
`
`Bah—DO5&2.
`
`><.._n_m_o
`
`mmMm
`
`m0<mmm._.2_mum:
`
`
`
`>m._._30w=0.
`
`mm
`
`3
`
`

`

`Patent Application Publication May 30, 2002
`
`Sheet 3 0f 7
`
`US 2002/0065065 A1
`
`
`
`moz<IUXmSwamo
`
`
`
`same585%.
`
`
`E<o~d40005mmzop<E<o<
`
`mw....
`
`
`DZ<401F200v.2....2900.—
`
`
`
`.
`
`mm|
`
`
`
`
`>mm>oomamo_>mmm..6528>zozam4mk
`
`
`Emmy480.6%..22%;”.$0.:685%.
`
`
`
`
`
`3.2.:AOOOHOmn—mm0<z<_2xz...
`
`
`
`
`
`
`
`..Nm..85«5.65200v.2:oz<mmm<m
`
`m.0.“—
`
`4
`
`
`
`
`
`
`
`
`
`

`

`Patent Application Publication May 30, 2002 Sheet 4 0f 7
`
`US 2002/0065065 A1
`
`
`
`FIG.'4
`
`L
`
`5%!
`'9
`
`IC
`
`D:
`
`E S
`
`80
`
`5
`
`

`

`Patent Application Publication May 30, 2002
`
`Sheet 5 0f 7
`
`US 2002/0065065 A1
`
`OE
`
`.8
`
`
`
`E052...
`
`III-IIIIIIcIlIlIIlllll'llllllllllll’llalullllllll.I.I."
`
`on
`
`GE
`
`mwmdmmzs
`
`QEon.
`
`mmjomkzoo
`
`aw....
`
`.wéfifo/GU
`
`:32:avuva.735
`
`dam.
`
`mzo_._.<o_..mm<
`
`.3xll.
`
`moéos<20
`
`8.
`
`6
`
`
`
`
`
`
`
`
`

`

`Patent Application Publication May 30, 2002 Sheet 6 0f 7
`
`US 2002/0065065 A1
`
`Phon'
`
`\53
`
`b\‘\
`
`7,\\ilXXH
`
`\ 5‘9
`
`USc
`
`“if”
`
`I
`
`51
`
`\Se
`
`\\
`\\
`.
`\Sd
`
`Pager
`
`FIG. 6A
`
`
`
`7
`
`

`

`Patent Application Publication May 30, 2002 Sheet 7 0f 7
`
`US 2002/0065065 A1
`
`the
`
`Initiate a data transfer operation
`using a GUI of a PD
`
`Establish a line-of-sight iFt
`communication link with an
`
`intended recipient
`
`Confirm the identity of the
`recipient with respect to the
`devices within RF
`
`communications range
`
`Set up a secure RF
`communications link with the
`
`identified recipient
`
`Execute the data transfer
`
`Present a confirmation of the
`
`completed data transfer to the
`
`user via the GUI 'ls's
`
`7. 1M
`
`TM»
`
`FIG. 7
`
`8
`
`

`

`US 2002/0065065 A1
`
`May 30, 2002
`
`METHOD AND SYSTEM FOR APPLYING LINE OF
`SIGHT IR SELECTION OF A RECEIVER TO
`IMPLEMENT SECURE TRANSMISSION OF DATA
`TO A MOBILE COMPUTING DEVICE VIA AN RF
`LINK
`
`TECHNICAL FIELD
`
`invention relates to a system and
`[0001] The present
`method by which a mobile computing device may more
`easily send and receive data. In particular,
`the present
`invention relates to a system and method for secure linking
`of a first mobile computing device to a second mobile
`computing device to enable wireless data transfer.
`
`BACKGROUND ART
`
`[0002] Personal Information Devices include the class of
`computers, personal digital assistants and electronic orga-
`nizers that tend both to be physically smaller than conven-
`tional computers and to have more limited hardware and
`data processing capabilities. PIDs include, for example,
`products sold by Palm, Inc. of Santa Clara, Calif., under
`such trademark as Pilot, and Pilot 1000, Pilot 5000, PalmPi-
`lot, PalmPilot Personal, PalmPilot Professional, Palm, and
`Palm III, Palm V, Palm VII, as well as other products sold
`under such trade names as WorkPad; Franklin Quest, and
`Franklin Convey.
`
`[0003] PIDs are generally discussed, for example, in US.
`Pat. Nos. 5,125,0398; 5,727,202; 5,832,489; 5,884,323;
`5,889,888; 5,900,875; 6,000,000; 6,006,274; and 6,034,686,
`which are incorporated herein by reference. PIDs typically
`include a screen and data processor, allowing the PID user
`to operate a substantial variety of applications relating to, for
`example: electronic mail, a calendar, appointments, contact
`data (such as address and telephone numbers), notebook
`records, expense reports, to do lists, or games. PIDs also
`often include substantial electronic memory for storing such
`applications as well as data entered by the user. Due to their
`substantial variety of applications and uses, personal infor-
`mation devices are becoming increasingly widely used.
`
`[0004] One popular application of personal information
`devices is their ability to easily share information with other
`properly equipped personal
`information devices. For
`example, many types of user information such as electronic
`mail, calendar events, appointments, contact data, and the
`like exist in the form of digital data files stored within the
`memory of the personal information device. When equipped
`with communications hardware/software,
`the data files
`embodying the user information can be easily transferred
`from one personal
`information device to another. For
`example, one such application involves the transferring of
`electronic “business cards” from one personal information
`device to another, allowing their respective users to easily
`exchange contact information.
`
`Infrared (IR) communications technology is one
`[0005]
`popular means for enabling the wireless transfer of digital
`data files between personal information devices. When prop-
`erly configured, one device can transfer selected user infor-
`mation (e.g., electronic business cards) to another device
`quickly and wirelessly. For example, the user can access a
`menu of user information Via a graphical user interface
`(GUI) of the personal information device. The user selects
`one or more items for transfer and beams the data file to the
`
`other personal information device. The use of IR commu-
`nications technology to effect such transfers is well known.
`
`[0006] RF communications technology provides another
`method for enabling the wireless transfer of digital data files
`between personal information devices. RF communications
`function in a manner similar to IR communications, in that
`when devices are properly equipped, one device can transfer
`selected user information (business cards, etc.) to another
`device wirelessly. Data selection and beaming can be con-
`trolled via GUI menus of the personal information device.
`
`[0007] However, RF communications beaming techniques
`are not readily suited for privacy. For example, due to the
`broadcast nature of RF transmissions, data beamed from a
`transmitting device tends to be available to other devices
`over a wide area. A transmitting device can have a large
`number of potential receiving devices within communica-
`tions range of the RF transmission. Thus, RF based trans-
`missions from one device to another are not as secure as a
`similar IR transmission from one device to another. The
`range and line of sight requirements/restrictions provide a
`relatively large degree of security.
`
`[0008] Thus, what is required is a solution that allows the
`secure wireless transfer of data between personal informa-
`tion devices without imposing constant line of sight restric-
`tions. What is required is a solution that allows secure data
`transfer between personal
`information devices without
`imposing constant, very short-range distance requirements.
`The required solution should be secure and determinative
`with respect to selecting the intended recipient in compari-
`son to prior art wireless beaming techniques. The present
`invention provides a novel solution to the above require-
`ments.
`
`SUMMARY OF THE INVENTION
`
`[0009] The present invention is a method and system for
`a method and system for applying line of sight IR selection
`of a receiver to implement secure transmission of data to a
`mobile computing device Via an RF link. The present
`invention provides a solution that allows the secure wireless
`transfer of data between personal information devices with-
`out imposing constant line of sight restrictions. The present
`invention provides a solution that allows secure data transfer
`between personal
`information devices without
`imposing
`constant, short-range distance requirements. Additionally,
`the solution of the present invention is secure and determi-
`native with respect to selecting the intended recipient in
`comparison to prior art wireless beaming techniques.
`
`In one embodiment, the present invention is imple-
`[0010]
`mented as a wireless communication method for secure
`
`transmission of data between mobile computing devices.
`The method includes the step of transmitting a line of sight
`beam from a first device to a second device to mutually
`identify the first device and the second device out of a
`plurality of devices. Once identified, the first and second
`devices establish an RF communications link between the
`identified first device and the identified second device.
`
`Using the RF communications link, the data transfer is then
`performed between the first device and the second device.
`The line of sight beam to select a secure transmission
`method for the RF communications link is an IR commu-
`nications beam. The RF communications link is a secure RF
`
`communications link recognizable only by the first and
`
`9
`
`

`

`US 2002/0065065 A1
`
`May 30, 2002
`
`second devices output of the plurality of devices. The RF
`communications is compatible with a version of the Blue-
`tooth specification. The secure transmission method is an
`encryption method for the RF communications link. Typi-
`cally, one of the mobile computing devices is a PID or a
`cellular telephone. Upon completion of the data transfer, a
`confirmation can be presented to the user.
`
`In this manner, the transmitting device can perform
`[0011]
`secure data transfers to the receiving device without being
`constrained by the constant
`line-of-sight and distance
`requirements of IR communication. Distance and line-of-
`sight need be within specified IR tolerances only for the
`initial identification and selection of secure transmission
`
`the two device need
`method. Once mutually identified,
`merely stay within RF communcations range. Thus, the user
`obtains the benefits of the wide, non-line-of—sight coverage
`of RF based communcation while retaining the security of
`point-to-point, line-of-sight IR based communication.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`invention is illustrated by way of
`[0012] The present
`example and not by way of limitation in the figures of the
`accompanying drawings, in which like reference numerals
`refer to similar elements, and in which:
`
`[0013] FIG. 1 is a diagram illustrating an exemplary
`preferred embodiment of the present system.
`
`[0014] FIG. 2 is a block diagram illustrating the layers of
`a radio frequency protocol stack used in the PID of FIG. 2.
`
`[0015] FIG. 3 shows a stack layer diagram illustrating the
`layers of an RF protocol stack in accordance with one
`embodiment of the present invention.
`
`[0016] FIG. 4 is a stack layer diagram illustrating layers
`of an Infrared Data Association protocol stack used in the
`PID of FIG. 2.
`
`[0017] FIG. 5 is a block diagram of the system of FIG. 1.
`
`[0018] FIG. 6A shows a diagram of a multiple recipient
`data transfer operation in accordance with one embodiment
`of the present invention.
`
`[0019] FIG. 63 shows a first GUI dialog box in accor-
`dance with one embodiment of the present invention.
`
`[0020] FIG. 6C shows a second GUI dialog box in accor-
`dance with one embodiment of the present invention.
`
`[0021] FIG. 7 is a flowchart illustrating an exemplary
`method for the system of FIG. 6A to execute data transfers
`to a single recipient or multiple recipients in accordance
`with one embodiment of the present invention.
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`
`In the following detailed description of the present
`[0022]
`invention, a method and system for applying line-of—sight IR
`selection of a receiver to implement secure transmission of
`data to a mobile computing device via an RF link, numerous
`specific details are set forth in order to provide a thorough
`understanding of the present invention. However, it will be
`obvious to one skilled in the art that the present invention
`may be practiced without these specific details. In other
`instances well known methods, procedures, components,
`
`and circuits have not been described in detail as not to
`obscure aspects of the present invention unnecessarily.
`
`[0023] Some portions of the detailed descriptions which
`follow are presented in terms of procedures, logic blocks,
`processing, and other symbolic representations of operations
`on data bits within a computer memory. These descriptions
`and representations are the means used by those skilled in
`the data processing arts to convey most effectively the
`substance of their work to others skilled in the art. A
`procedure,
`logic block, process, step, etc.,
`is here, and
`generally, conceived to be a self-consistent sequence of steps
`or instructions leading to a desired result. The steps are those
`requiring physical manipulations of physical quantities.
`Usually, though not necessarily, these quantities take the
`form of electrical or magnetic signals capable of being
`stored,
`transferred, combined, compared, and otherwise
`manipulated in a computer system. It has proven convenient
`at times, principally for reasons of common usage, to refer
`to these signals as bits, values, elements, symbols, charac-
`ters, terms, numbers, or the like.
`
`It should be borne in mind, however, that all of
`[0024]
`these and similar terms are to be associated with the appro-
`priate physical quantities and are merely convenient labels
`applied to these quantities. Unless specifically stated other—
`wise as apparent from the following discussions, it is appre-
`ciated that throughout the present invention, discussions
`utilizing terms such as “implementing,’"‘transferring,”“ex-
`ecuting,"“configuring,"“initializing,” or the like, refer to the
`actions and processes of an embedded computer system, or
`similar embedded electronic computing device, that manipu-
`lates and transforms data represented as physical (electronic)
`quantities within the computer system’s registers and memo-
`ries into other data similarly represented as physical quan-
`tities within the computer system memories or registers or
`other such information storage,
`transmission or display
`devices.
`
`[0025] The present invention is a method and system for
`a method and system for applying linc-of—sight IR selection
`of a receiver to implement secure transmission of data to a
`mobile computing device via an RF link. The present
`invention provides a solution that allows the secure wireless
`transfer of data between personal information devices with-
`out imposing constant line-of-sight restrictions. The present
`invention provides a solution that allows secure data transfer
`between personal
`information devices without
`imposing
`constant, very short-range distance requirements. Addition-
`ally,
`the solution of the present invention is secure and
`determinative with respect to selecting the intended recipient
`in comparison to prior art wireless beaming techniques.
`Embodiments of the present invention and its benefits are
`further described below.
`
`It should be noted that the method and system of
`[0026]
`the present invention can be configured to enable secure
`wireless communication between a number of types of
`mobile computing devices. Such mobile computing devices
`include, for example, personal information devices (PIDs),
`handheld cellular telephones (cellphones) and other types of
`mobile telephones, alphanumeric paging devices, and the
`like.
`
`[0027] FIG. 1 shows an exemplary embodiment of a
`system 10 in accordance with one embodiment of the
`present invention. The system 10 includes a handheld PID
`
`10
`
`10
`
`

`

`US 2002/0065065 A1
`
`May 30, 2002
`
`12 and a PID 14. As described above, the preferred embodi-
`ment utilizes a PID 12 communicatively coupled to a second
`PID 14. However, many electronic devices, such as digital
`cameras, limited feature pagers, laptop computers, and the
`like, are similar to many PIDs in that they can exchange and
`make use of the scheduling information contained within a
`user PID. Limited-feature devices may also be enhanced by
`coupling the devices with a PID in accordance with the
`present invention to exchange and view data stored on the
`PID.
`
`[0028] As shown in FIG. 1, the PID 12 of the present
`system 10 includes a wireless port, or transceiver, 16 (used
`herein to mean some combination of a receiver and/or
`transmitter). The PID 14 has a corresponding wireless port,
`or transceiver, 18 such that a wireless link 20 is established
`between the PID of 14 and PID 12.
`
`In one preferred embodiment, the wireless ports 16,
`[0029]
`18 cach includc a short-range radio frcqucncy (RF) trans-
`ceiver. The wireless transceiver 16, 18 establish an RF link,
`such as that defined by the Bluetooth communications
`specification. Additionally,
`the link 20 can also include
`support for other modes of communication, including an
`infrared communication links such as that as defined by the
`Infrared Data Association (IrDA).
`
`[0030] FIG. 2 is a function block diagram showing an
`exemplary embodiment of the PID 12 that can communicate
`with the PID 14 or other such devices. The link interface
`circuitry 26 illustrates, but is not limited to, two alternative
`link interfaces for establishing a wireless link to another
`device. One wireless link interface (or more than two link
`interfaces) may, of course, be used with the present system
`10.
`
`[0031] The PID 12 includes a processor, or controller, 28
`that is capable of executing an RF stack 30 and an erA
`stack 32. The stacks 30, 32 communicate with data interface
`circuitry 26 through a bus 34. The processor 28 is also
`connected through the bus 34 to user interface circuitry 36,
`a data storage module 38 and memory 40. As used herein,
`the data storagc modulc 38 and memory 40 may both
`generally be referred to as part of the PID memory 41.
`
`[0032] The memory 40 may contain a specific remote
`control loading application 42. The remote control loading
`application 42 may operate, for example, after the processor
`28 receives a message for the user to establish a wireless link
`with the PID 14 in the nearby environment. Alternatively,
`the remote control loading application 42 may operate in a
`PID default mode.
`
`in this
`[0033] The data interface circuitry 26 includes,
`exemplary embodiment, a first and second port, such as,
`infrared and RF interface ports. The first wireless link
`interface, the RF link interface, may include first connection
`44 which includes radio-frequency (RF) circuitry 46 for
`converting signals into radio-frequency output and for
`accepting radio-frequency input. The RF circuitry 46 can
`send and receive RF data communications via a transceiver
`
`that are part of the communication port 16. The RF com-
`munication signals received by the RF circuitry 46 are
`converted to electrical signals and relayed to the RF stack 30
`in processor 28 via the bus 34.
`
`link 20 between the PID 12 and PID 14 may be implemented
`according to the Bluetooth specification, described at www-
`.bluetooth.com, which is incorporated in its entirety into this
`document.
`
`[0035] Bluetooth is the protocol for a short-range radio
`link intended to replace the cable(s) connecting portable
`and/or fixed electronic devices. Bluetooth technology fea—
`tures low power, robustness, low complexity and low cost.
`It operates in the 2.4 Ghz unlicensed ISM (Industrial,
`Scientific and Medical) band. Devices equipped with Blue—
`tooth are capable of exchanging data at speeds up to 720
`kbps at ranges up to 10 meters. It should be noted that higher
`power devices other than the typical Bluetooth enabled PID,
`such as, for example, a network access point, may commu-
`nicate via Bluetooth with an RF-enabled PID over a greater
`range, such as, for example, approximately 100 meters.
`
`[0036] A frequency hop transceiver is used to combat
`interface and fading. A shaped, binary FM modulation is
`applied to minimize transceiver complexity. A slotted chan-
`nel is applied with a nominal slot length of 625 ,us. For full
`duplex transmission, a Time Division Duplex scheme is use.
`On the channel, information is exchanged through packets.
`Each packet is transmitted in a different hop frequency. A
`packet nominally covers a single slot, but can be extended
`to cover up to five slots.
`
`[0037] The Bluetooth protocol uses a combination of
`circuit and packet switching. Slots can be reserved for
`synchronous packets. Bluetooth can support an asynchro-
`nous data channel, up to three simultaneous voice channels,
`or a channel,
`that simultaneously supports asynchronous
`data and synchronous voice. Each voice channel supports a
`64 kb/s synchronous (voice) channel in each direction. The
`asynchronous channel can support maximum 723.2 kb/s
`asynchronous, or 433.9 kb/s symmetric.
`
`[0038] The Bluetooth system consists of a radio unit, a
`link control unit, and a support unit for link management and
`host terminal interface functions. The link controller carries
`out the baseboard protocol and other low—level routines.
`
`[0039] The Bluetooth system also provides a point-to-
`point connection (only two Bluetooth units involved) or a
`point-to-multipoint connection. In point-to-multipoint con-
`ncctions, thc channcl is sharcd among several Bluctooth
`units. Two or more units sharing the same channel form a
`piconet. One Bluetooth unit acts as the master of the piconet,
`whereas the other units act as slaves. Up to seven slaves can
`be active in a piconet.
`
`[0040] The Bluetooth link controller has two major states:
`STANDBY and CONNECTION.
`In addition,
`there are
`scvcn substances: pagc, pagc scan, inquiry, inquiry scan,
`master response, slave response, and inquiry response. The
`substances are interim states that are used to add new slaves
`
`to the piconet.
`
`[0041] The STANDBY state is the default state in the
`Bluetooth unit. In this state,
`the Bluetooth unit is in a
`low-power mode. The controller may leave the STANDBY
`state to scan for page or inquiry messages, or to page or
`inquiry itself. When responding to a page message, the unit
`enters the CONNECTION state as a master.
`
`[0034] The PID 14 includes a corresponding port, or
`transceiver, 18 for RF signals. Thus, the RF 24 and wireless
`
`In order to establish new connections, the inquiry
`[0042]
`procedures and paging are used. The inquiry procedures
`
`11
`
`11
`
`

`

`US 2002/0065065 A1
`
`May 30, 2002
`
`enable a unit to discover which units are in range, and what
`their device address and clocks are during an inquiry sub-
`state,
`the discovering unit collects the Bluetooth device
`addresses and clocks of all units that respond to the inquiry
`message. It can then, if desired, make a connection to any
`one of them. The inquiry message broadcasted by the source
`does not contain and information about the source. However,
`it may indicate which class of devices should respond.
`
`[0043] There is one general inquiry access code (GIAC) to
`inquire for any Bluetooth device, and a number of dedicated
`inquiry access codes (DIAC) that only inquire for a certain
`type of devices. Aunit that wants to discover other Bluetooth
`units enters an inquiry substate. In this substance, it con-
`tinuously transmits the inquiry message (which is an iden-
`tification packet) at different hop frequencies. A unit that
`allows itself to be discovered, regularly enters the inquiry
`scan substance to respond to inquiry messages.
`
`[0044] Asccond connection 46 includes infrared circuitry
`48 for converting signals into infrared output and for accept-
`ing infrared input. Thus, the wireless link 28 can include an
`infrared interface. The infrared circuitry 48 can send and
`receive infrared data communications via the port, or trans-
`ceiver, 16.
`
`Infrared communication signals received by infra-
`[0045]
`red circuitry 48 are converted into electrical signal that are
`relayed to the IrDA stack 32 in the processor, or controller,
`28 via the bus 34. The PID 14 may include a corresponding
`infrared transceiver. The infrared circuitry 48 operates
`according
`to
`the
`IrDA specifications
`available
`at
`www.IrDA.org.
`
`It should be noted that the specific format of the
`[0046]
`two link interfaces described above can be altered in accor-
`
`dance with the specific needs of the user, and as such,
`additional means for implementing the interface between a
`PID and telephone or other such device may be utilized. In
`the present embodiment, the RF (Bluetooth) link is wide
`area, non-line-of-sight and the IR (IrDA) link is point-to-
`point,
`line-of-sight. The two wireless links are used to
`implement
`the secure data transmission method of the
`present invention.
`
`[0047] User interface circuitry 36 in the PID 12 included
`hardware and software components that provide user input
`and output resources for functions in the processor 28. The
`user interface circuitry 36 includes display output 50, dis-
`play input 52, and additional input/output interface circuitry
`54.
`
`[0048] The display output 50 preferably receives digital
`information representing graphical data from the processor
`28 and converts the information to a graphical display, such
`as text and or/images, for display on a display screen. The
`display input 52 may receive data inputs, such as graphical
`data inputs, from a user of the PID 12. The graphical data
`inputs are preferably entered by the user with a stylus on a
`pressure sensitive display screen, and may include text,
`drawings, or other objects that are capable of being graphi-
`cally presented.
`
`[0049] Typically, the additional input/output interface 54
`permits user input and commands to be input
`through
`buttons and similar devices on the PID, e.g., buttons for
`scrolling through data entries and activating applications.
`Alternatively, the input/output interface 54 may allow the
`
`PID 12 to accept audio data as well as other types of
`non-graphical data. For example, audio data signals (or
`picture telephone video input) may be entered through the
`additional input/output interface 54.
`
`[0050] FIG. 3 shows a diagram illustrating the layers of
`the Bluetooth (RF) protocol stack 60 in accordance with one
`embodiment of the present invention. An RF protocol stack
`is implemented at each end of the connection endpoints of
`an RF link. For example, a PID 12 and a telephone 14 could
`each implement an RF stack to enable a link. The required
`layers of the RF link using the Bluetooth system are the
`Baseband layer 62, the Link Manager Protocol Layer (LMP)
`64,
`the Logical Link Control and Adaptation Layer 68,
`RFCOMM Layer 70, Service Discovery Protocol Layer 72,
`and Object Exchange Protocol (OBEX) layer 74.
`
`[0051] FIG. 4 is a protocol diagram 80, illustrating the
`layers of the IrDA protocol stack that may be used with the
`system 10. For example, the PID and the telephone 41 each
`implement an IrDAprotocol stack to enable the wireless link
`20.
`
`[0052] The rcquircd layers of an IrDA protocol stack arc
`the physical layer 82, the IrLMP layer 84, the IrLMP layer
`86 and the LAS layer 88. The physical layer 82 specifies
`optical characteristics if the link, encoding of the data, and
`framing for various speeds. The IrLAP (Link Access Pro-
`tocol) layer 84 establishes the basic reliable connection
`between the two ends of the link. The IrLMP (Link Man—
`agement Protocol) layer 86 multiplexes services and appli-
`cations on the IrLAP connection. The IAS (Information
`Access Service) layer 88 provides a directory of services on
`an IrDA device.
`
`[0053] The IrDA protocol also specifies a number of
`optional protocol layers, these protocol layers being TINY
`TP90, IrOBEX 92, IrCOMM 94 and IrLAN 96. TINY TP
`(Tiny Transport Protocol) 90 adds per-channel flow control
`to keep traffic over the link 20 moving smoothly. IrOBEX
`(Infrared Object Exchange Protocol) 92 provides for the
`easy transfer of files and other data objected between the
`IrDA devices at each end of the applications that use serial
`and parallel communications to use IrDA without change.
`IrLAN (Infrared Object Exchange Protocol) 92 provides for
`the easy transfer of files and other data objects between the
`IrDA devices at each end of the link 20. IrCOMM 94 is a
`
`serial and parallel communications to use IrDA without
`change. IrLAN (Infrared Local Area Networks) 96 enables
`walk-up infrared LAN access.
`
`[0054] The use of the optional layers depends upon the
`particular application in the IrDA device. The IrDA protocol
`stack is defined by such standard documents as “IrDA Serial
`Infrared Physical Layer Link Specification”,
`“IrDA
`‘IrCOMM’: Serial and Parallel Port Emulation over IR (wire
`replacement)”, “IrDA Serial Infrared Link Access Protocol
`(IrLAP)”,
`“IrDA Infrared Link Management Proto-
`col(IrLMP)”, and “IrDA ‘TINY TP”: A Flow-Control
`Mechanism for use with IrLMP, and related specification
`published by the IrDA. Such documents are available at
`www.irda.org/standards/specifications.asp and are incorpo-
`rated in their entirety in this document.
`
`the PID 12 may include
`[0055] As shown in FIG. 5,
`resident applications 100,. such as, for example, a schedul-
`ing program 101 for managing schedule information. The
`
`12
`
`12
`
`

`

`US 2002/0065065 A1
`
`May 30, 2002
`
`PID 12 may include as well, for example, an events man-
`agement program 109 for recording the start time and stop
`time of special events, a calendar program 102 for assisting
`in managing scheduling and events, and a user preferences
`program 104 for configuring PID 12 in accordance with the
`requirements of the user.
`
`[0056] PID 12 and PID 14 implement the secure commu-
`nication method of the present invention. PID 12 uses a
`line-of-sight IR communication with PID 14 in order to
`mutually select each other and set up the parameters (e.g.,
`encryption, coding, etc.) for implementing a secure trans-
`mission of data via an RF link 20. In the present embodi-
`ment, the IR communication is in accordance with the IrDA
`protocols described above, and the RF communication is in
`accordance with the Bluetooth specifications described
`above.
`
`[0057] Referring still to FIG. 5, with the advent of short—
`range RF data transmission enabled by by the Bluetooth
`standard comes a benefit that can also be a problem. Blue-
`tooth allows RF data transmission without the line-of-sight
`required for IR data transmissions. In most situations, the
`non-line-of—sight characteristics of RF data transmission are
`beneficial. RF data transmission enables the “beaming” of
`data without users having to point their devices (e. g., PID 12
`and PID 14) directly at each other. However, there are times
`when a user will want
`to select the device intended for
`
`receipt of RF data by manually pointing to the receiving
`device. For example, imagine that a user wants to RF-beam
`“e-cash” to a cash register, or RF-beam confidential infor-
`mation to a previously unknown/unrecognized Bluetooth
`enabled Network Access Point. It is important that the e-cash
`not be beamed to the wrong cash register and the confiden-
`tial information not be beamed to an unintended recipient.
`The secure data transmission method of the present inven-
`tion solves this problem by using a line-of-sight IR link to
`identify an intended recipient and set up the param