lllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllll
`US005602903A
`
`Ulllted States Patent
`LeBlanc et al.
`
`[19]
`
`[11] Patent Number:
`[45] Date of Patent:
`
`5,602,903
`Feb. 11, 1997
`
`[54] POSITIONING SYSTEM AND IVIETHOD
`
`[75]
`
`Inventors: Frederick W. Lelilanc, Arveda;
`Gregory E_ Wilson; Alparsian M_
`Uysal, both of Boulder, all of Colo.
`
`[73] Assignee: US West Technologies, Inc., Boulder,
`C°1°-
`9
`
`[21] Appl. No.:314,477
`[22]
`Filed:
`Sep. 28, 1994
`
`Int. Cl.“ ................................ H04Q 7/22;GO1S 3/02
`(51)
`[52] US. CL
`379/50; 379/59; 342/450;
`342/457
`
`........... 379/53, 59,61,
`[53] Field or Search .....
`379/45. 37. 50, 51; 342/450. 451, 452,
`453. 454» 457, 453, 453; 370/ 5 10-11 455/57-1.
`33-1
`
`[56J
`
`References Cited
`U'S_ PATENT DOCUMENTS
`6/1975 Flfilchfir -
`10/1977 Diflabfllds 9‘ 31- -
`1/1989 S‘“‘d""f°‘d' Jr’ C‘ “L '
`5/1989 Palmer et al.
`.
`10/1989 Selby _
`12,1989 Friedman _
`1/1990 Sheffer.
`8/1991 Darnell et al. .
`
`3.389.264
`4-054v38°
`4399962
`4,833,480
`43761738
`4_888_595
`4,891,650
`5,043,736
`
`5,055,851
`
`10/1991 Shefier .
`
`.
`
`3/1992 Cosentino .
`5.097.499
`4/1992 Gilhouscn el al.
`5,103,459
`5-173710 12/1992 K6110)’ Cl 51- -
`5,179,721
`1/1993 Comroe et al. .
`5’2O8'756
`5/1993 S°"g '
`5,216,429
`6/1993 Nakagawa etal..
`5,218,367
`6/1993 Shetfer et al. .
`5,218,629
`6/1993 Dumond‘ Jn at al_ .
`5,221,925
`5/1993 Cross.
`5,223,844
`6/1993 Mansell et al.
`.
`5,280,295
`1/1994 Kelley er. al..
`2/1995 Grimes
`5,388,147
`
`Primary Examiner~—Curtis Kuntz
`Am-,,a,,, Exm,-,,e,_M,-Chaet B_ Chemog
`Azzarngy, Agent, or F;'nn——Brook5 & Kushmgm, RC,
`
`‘WSTRACT
`(571
`An improved positioning system and method for use in a
`wireless communication system including a plurality of base
`stations each having a corresponding coverage area Scaled
`contour shapes are generated having minimum and maxi-
`mum boundaries based upon determined RF measurements
`of each of the base stations. The intersections of thecontour
`shapes define a bounding polygon area that describes the
`osition of a mobile unit in tenns of minimum and maxi-
`1I')num error estimate. Once the bounding polygon area has
`been defined the latitude and longitude of the center of the
`1
`'. . d t
`. Cd
`h
`d.
`t
`I
`po ygon area is c cnnin w ereupon cozrespon ing 5 rec
`addresses may be obtained through reference to one or more
`d3t3b3SCS-
`
`19 Claims, 20 Drawing Sheets
`
`Detarminlnut-1F measurements for each (time
`base stations as asqatco contour shape having
`minimum and maximum bnundrias which Is
`capable at being pmiected on /1 digital
`ortndpndtograph
`
`
`
`
`
`,9?
`
`Ni
`
`Determining which of the base stations are
`neighbursolthemobtle unit
`
`
`
`
`
`
`19,;
`
`corresponding
`the
`Determining where
`contours or
`the neighbor base stations
`tntersactsn asto dsilneatmundtn poly on
`‘L area that describes the position oft emu lte
`unittntermsotaminimumandmaximumerror
`estimate
`
`
`
`
`198
`
`the bounding
`Determining the center oi
`polygon area termed by the intersection in the
`sta ons
`prdktectad contours at the neighbor hase
`
`
`
`calculating the latitude and longitude tor the
`center oithahounding polygon
`
`
`Appletnc.
`
`Exhibit1011
`
`Page1
`
`202
`
`
`
`Determining in cooperation with a run-time
`
`database. the exact street addresses contained
`wilhinthehuundingpalygon area
`
`
`
`

`
`U.S. Patent
`
`Feb. 11, 1997
`
`Sheet 1 of 20
`
`5,602,903
`
`PUBLIC
`SWITCHED
`TELEPHONE
`NETWORK
`
`MOBILE TELEPHONE
`SWITCHING CENTER
`
`CONTROL CALL
`PROCESSOR
`
`'
`
`2?? I /flf.’f02‘f'«’~71€7/'
`
`Applelnc.
`
`Exhibit1011
`
`Page2
`
`

`
`U.S. Patent
`
`Feb. 11, 1997
`
`Sheet 2 of 20
`
`5,602,903
`
`RPC1
`
`CALL
`
`“NE
`Rou(«'3t’r\NLc;LANo
`ROUTING AND
`MONITORING
`5W”C”'”G
`MONITORING
`
` RPCn
`
`
`
`MESSAGES
`
`
`
`
`
`“"5
`SW‘T°”'“G
`
`..
`
`
`v/muons
`
`
`‘i’ TRANSPORT
`V
`\\\
`
`
`
`::\§ \
`\
`
`Apple Inc.
`
`Exhibit 1011
`
`Page 3
`
`

`
`U.S. Patent
`
`Feb. 11, 1997
`
`Sheet 3 of 20
`
`5,602,903
`
`52
`
` Radio
`Termination
`
`
`
`Termination
`Type 1
`
`
`
`44
`
`
`
` Radio
`
`Personal
`Terminal
`
`
`
`Appielnc.
`
`Exhibit1011
`
`Page4
`
`

`
`U.S. Patent
`
`Feb. 11, 1997
`
`Sheet 4 of 20
`
`5,602,903
`
`Terminal
`Mobility
`
`Terminal
`Mobility
`Controller
`
`ty
`
`Data-Store 42 Access System
`
`Personal
`Mobility
`Data-Store
`(PMD)
`
`Controller
`
`Apple Inc.
`
`Exhibit 1011
`
`Page 5
`
`

`
`U.S. Patent
`
`Feb. 11, 1997
`
`Sheet 5 of 20
`
`5,602,903
`
`
`
`External Netzuorks
`
`WIRELESS COMMUNICATION
`SYSTEM SUBSCRIBER
`
`93
`
`CONTROL
`
`100
`
`
`
`702
`
`
`
`
`LOCATION
`ADJUNCT
`
`PROCESSOR
`DATABANKN
`
`
`
`
`
`
`
`LOCATIO N
`
`Apple Inc.
`
`ExhibIt1011
`
`Page6
`
`

`
`U.S. Patent
`
`Feb. 11, 1997
`
`Sheet 6 of 20
`
`5,602,903
`
`IIIIIIII IIII I
`
`I
`II
`
`IIIIIIIIIIIII
`
`
`
`LOCATION
`
`,- DATABANK --
`
`STP
`
`Synthesizer
`
`132
`
`Public Safety Answerin
`_
`Poinl (PSAP)
`
`
`
`Public Safety Answering
`Point (PSAP)
`
`/
`
`146'
`
`Public Safety Answering
`Point (PSAP)
`
`132
`
`
`
`
`
`Location
`Adjunct
`Processor
`_,-Database -_
`
`
`Applelnc.
`
`Exhibit1011
`
`Page7
`
`

`
`U.S. Patent
`
`Feb. 11, 1997
`
`Sheet 7 of 20
`
`5,602,903
`
`150
`
`Apple Inc.
`
`Exhibit 1011
`
`Page 8
`
`

`
`U.S. Patent
`
`Feb. 11, 1997
`
`Sheet 8 of 20
`
`5,602,903
`
`Server
`
`socket()
`
`
`
`.
`_
`btocks until connectaon
`from client
`
`client
`
`socket()
`
`connection established
`
`
`
`
`
`
`
`process request
`
`
`
`1”
`
`Apple Inc.
`
`Exhibit 1011
`
`Page 9
`
`

`
`U.S. Patent
`
`Feb. 11, 1997
`
`Sheet 9 of 20
`
`5,602,903
`
`794
`
`198
`
`202
`
`
`
`Determining RF measurements for each ofthe
`base stations as a scaled contour shape having
`minimum and maximum boundries which is
`capable of being projected on a digital
`orthophotograph
`
`Determining which of the base stations are
`neighborsofthemobileunit
`
`corresponding
`the
`Determining where
`contours
`of
`the neighbor base stations
`intersect so as to define a bounding poly%on
`area that describes the position of the mo ile
`unit interms ofa minimum and maximum error
`estimate
`
`stations
`
`the bounding
`Determining the center of
`polygon area formed by the intersection of the
`projected contours of
`the neighbor base
`
`
`
`Determining in cooperation with a run-time
`database. the exact street addresses contained
`within the bounding polygon area
`
`Calculating the latitude and longitude for the
`centerofthe bounding polygon
`
`192
`
`196
`
`zoo
`
`Apple inc.
`
`Exhibit 1011
`
`Page 10
`
`

`
`U.S. Patent
`
`Feb. 11, 1997
`
`Sheet 10 of 20
`
`5,602,903
`
`
`
`Amag
`
`—— Actual values
`— —— ~~ Predicted values
`
`
`
`has
`3
`
`300%
`‘
`
`i700
`500
`Distanoe in Feet
`
`900%
`'
`
`
`1100
`
`RS850
`
`Propagation
`Path Loss
`in dB
`
`'50
`
`WERdown
`
`Word Error
`Rate %
`
`3
`
`g"'2’fy,1é3
`
`0
`
`100
`
`300
`
`700
`500
`Distance in Feet
`
`900
`
`1100
`
`
`
`sliding window
`
`. 21'
`2¥§_ "
`‘mes
`deviation
`
`1000
`
`800
`
`Distance
`In Feet 600
`
`400
`
` avg. -2 times
`std. deviation
`
` 200
`-70
`-so
`-50
`-40
`-30
`
`3%?’ 1)’)
`
`Propagation Path Loss (dB)
`
`Apple Inc.
`
`Exhibit1011
`
`Page11
`
`

`
`U.S. Patent
`
`Feb. 11, 1997
`
`Sheet 11 of 20
`
`5,602,903
`
`0
`
`N‘‘CC’..."...v
`QOOOOOOOOOOQOQOOOOOOOOO
`’Q.‘......‘O.'...C'
`
`ouooo
`
`cocoon.
`:ococoonoa.
`99069.
`
`37.?» 14
`
`Apple Inc.
`
`Exhibit1011
`
`Page12
`
`
`
`
`

`
`5,602,903
`
`

`
`3wmmm
`:2Sim
`.2:m_nE<
`
`U.S. Patent
`
`Feb. 11, 1997
`
`Sheet 13 of 20
`
`5,602,903
`
`E
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`U.S. Patent
`
`bm
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`.41
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`309.,
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`mSN
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`U.S. Patent
`
`Feb. 11, 1997
`
`Sheet 15 of 20
`
`5,602,903
`
`%\
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`
`
`x:==;ou_mmm
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`

`
`U.S. Patent
`
`Feb. 11, 1997
`
`Sheet 17 of 20
`
`5,602,903
`
`400
`
`342.857
`
`285.714
`
`228.571
`
`Distance(m) 171.428
`
`114.286
`
`57.1428
`
`~11O
`
`-92.8571
`
`-75.7142
`
`-58.5714
`
`RSS1 upiink
`
`20
`
`21
`
`Apple Inc.
`
`Exhibit 1011
`
`Page 18
`
`

`
`U.S. Patent
`
`Feb. 11, 1997
`
`Sheet 18 of 20
`
`5,602,903
`
`2.?
`
`24
`
`
`
`Apple Inc.
`
`Exhibit 1011
`
`Page 19
`
`

`
`U.S. Patent
`
`Feb. 11, 1997
`
`Sheet 19 of 20
`
`5,602,903
`
`308
`
`Segmenting the coverage areas of each of the base stations into a plurality
`of arc segments
`
`370
`
`Performing a plurality of single or multiple regressions so as to convert actual
`data into a corresponding plurality of mathematical curve-tit equations each
`representing a relationship between a predetermined measurable variable and
`distance from the base station
`
`
`
`272
`
`Determining the degree of curve fit of each of the mathematical equations by
`comparrngthem with actual data
`
`214
`
`Optimizing the mathematical equations by determining which has the best
`correlation and least standard errorior a predetermined portion of each arc
`
`segment
`
`216
`
`E
`'
`
`Combining the optimized mathematical equations for each arc segment so as
`to form a scaled contour
`
`Max. Boundary
`
` 218
`
`Min. Boundary
`
`3&0
`
` 222
`
`Apple Inc.
`
`Exhibit 1011
`
`Page 20
`
`

`
`U.S. Patent
`
`Feb. 11, 1997
`
`Sheet 20 of 20
`
`5,602,903
`
`
`
`E‘/"‘..°/A‘: .lE''\‘T''
`.
`.. ~ EA 111
`
`
`
`\
`
`.
`
`TL:
`1»
`
`I
`
`I
`
`Apple Inc.
`
`Exhibit1011
`
`Page 21
`
`

`
`5,602,903
`
`1
`POSITIONING SYSTEM AND METHOD
`
`TECHNICAL FIELD
`
`The present invention relates generally to positioning
`systems. More particularly the invention relates to a method
`and system for determining the position of a mobile unit in
`a wireless communication system or public land mobile
`telecommunications system including a plurality of base
`stations by generating and analyzing scaled contour shapes
`having minimum and maximum boundaries for each of the
`base stations in accordance with their individual RF mea-
`surements.
`
`BACKGROUND ART
`
`Most metropolitan areas are now equipped with one or
`more forms of wireless communication networks which
`provide mobile telephone and other related services to
`customers across a broad frequency spectrum. Consider, for
`example, what has come to be known as “cellular” telephone
`services or Personal Communication Services “PCS", i.e.,
`radio transmissions in the frequency hand between approxi-
`mately SOO MHZ and 2.2 GHZ.
`As shown in FIG. 1, prior art cellular telephone systems
`10 include a Mobile Telephone Switching Center (MTSC)
`12 and a plurality of base stations such as cell site trans-
`ceivers 14a—14c. The cell site transceivers transmit radio
`signals to and receive radio signals from one or more mobile
`units 16 that move about a cellular service area 20. A mobile
`unit, as the term is used herein, refers to a wireless voice
`telephone or data receiver that can be permanently installed
`at a fixed location or within a vehicle or that can be portable.
`Each cell site transceiver 14 is able to broadcast and receive
`the radio signals within a geographic area 18 called the cell
`site coverage area. Together. the areas 18 comprise the entire
`cellular service area 20. Typically, a cellular service area
`comprises a metropolitan area or larger region.
`When a telephone call to :1 called mobile unit 16 origi-
`nates from either another mobile unit or a land-based
`telephone via aPublic Switched Telephone Network (PSTN)
`22, a caller must first access the cellular telephone system
`10. This task is accomplished by dialing the mobile uru't’s
`unique identification number (i.e., its phone number). The
`MTSC 12 receives the call request and instructs the control
`unit, i.e., the central call processor 7A to begin call process-
`ing. The central cull processor 24 transmits a signal over a
`dedicated line 26 (such as a telephone line or microwave
`link, etc.) to each of the cell site transceivers 14a—14c
`causing the cell site transceivers to transmit a page signal
`that the mobile unit 16 receives. The page signal alerts a
`particular mobile unit 16 that it is being called by including
`as part of the page signal the paged mobile unit’s identifi-
`cation or phone number.
`Each cell site transceiver 14 transmits the page signal on
`one or more dedicated forward control channels that carry
`all pages, as well as control signals, channel assignments,
`and other overhead messages to each mobile unit. The
`forward control channel is distinct from the voice channel
`that actually carries voice communications between a
`mobile and another mobile unit or a land~ba3cd telephone.
`Each cell site transceiver may have more than one forward
`control channel upon which pages can be carried.
`When 21 mobile unit is not engaged in a telephone call, it
`operates in an idle state. In the idle state, the mobile unit will
`tune to the strongest available forward control channel and
`monitor the channel for a page signal or other messages
`
`10
`
`I5
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`65
`
`2
`directed to it. Upon determining that a page signal is being
`transmitted,
`the mobile unit 16 again scans all forward
`control channels so as to select the cell site transceiver
`14a—14c transmitting the strongest signal. The mobile unit
`then transmits an acknowledgement signal
`to the cell site
`transceiver over a reverse control channel associated with
`the strongest forward control channel. This acknowledge-
`ment signal serves to indicate to the MTSC 12 which of the
`forward control channels (associated with the several cell
`site transceivers 14a-14c) to use for further call processing
`communications with mobile unit 16. This further commu-
`nication typically includes a message sent to the mobile unit
`instructing it
`to tune to a particular voice channel
`for
`completion of call processing and for connection with the
`calling party.
`The details of how the cell site transceivers transmit the
`signals on the forward and reverse control channels are
`typically governed by standard protocols such as the EIA/
`TIA-553 specification and the air interface standards for
`Narrowband Analog Mobile Phone Services (NAMPS)
`IF-88 and IS-95 air interface standards for digital commu-
`nications, all of which are well known to those of ordinary
`skill
`in the wireless telephone communications art and
`therefore will not be discussed.
`While cellular networks have been found to be of great
`value to mobile users whose travels span many miles. they
`have also been found to be prohibitively expensive to
`implement
`for small scale applications wherein system
`subscribers only desire wireless telephone services in lim-
`ited geographic areas, such as, for example, within ofiice
`buildings or in campus environments.
`The Personal Communications Network (PCN) is a rela-
`tively new concept in mobile communications developed
`specifically to serve the aforementioned applications. Simi-
`lar to cellular telephony goals, a Personal Communications
`Network goal is to have a wireless communication system
`which relates telephone numbers to persons rather than fixed
`locations. Unlike cellular telephones, however,
`the PCN
`telephones are directed to small geographic areas thus
`defining “microcellular" areas designed to operate in similar
`fashion to large scale cellular telephone networks. PCN
`technologies are also similar to residential cordless tclc-
`phones in that they utilize base stations and wireless hand-
`sets. Unlike the former, however, PCN technology utilizes
`advanced digital communications architecture, such as, for
`example, PACS, formerly called WACS, (Bellcorc), DECT
`(European), CDMA (Omni—point), PHS—Pl-JP (Japan), IS-54
`(TDMA), IS-95 (CDMA), PCS-1900 (GSM), and B-CDMA
`(Oki), and features which may be implemented either as
`private networks or regulated services. When offered by
`communications carriers as services, this PCN capability is
`generally referred to as Personal Communications Services
`(PCS), and may be situated in a wide variety of environ-
`ments,
`including, for example, outdoor urban, suburban,
`rural, indoor single-level and indoor mu1ti—leve1 areas.
`As shown in FIG. 2, prior art PCS systems 28 include one
`or more control units 30 which, in accordance with the
`American National Standards Institute (ANSI) TlPl work-
`ing document for stage 2 service description, as known to
`those skilled in the art, are termed Radio Port Controllers
`(R.PCs), Radio Access System Controllers (RASCS), access
`managers, etc. These control units 30 operate in similar
`fashion to the MTSC 12 of the cellular telephone network
`and,
`therefore, are provided in electrical communication
`with the Public Switched Telephone Network 22. Aplurality
`of base stations or Radio Ports (RPS) 32 are also provided
`which transmit radio signals to and receive radio signals
`
`Apple Inc.
`
`Exhibit 1011
`
`Page 22
`
`

`
`3
`from one or more subscriber wireless telephones 16, termed
`mobile units or Radio Personal Terminals (R.PTs) that move
`about a PCS service area 34. Each Radio Port 32, like cell
`site transceivers I4, is able to broadcast and receive radio
`signals within a geographic area 36 called the Radio Pon
`coverage area. Togedter, the areas 36 comprise the entire
`PCS service area 34.
`
`15
`
`25
`
`30
`
`35
`
`40
`
`45
`
`A generalized reference architecture for the PCS system
`of FIG. 2 is shown in further detail in FIGS. 3a—3b. The
`reference architecture includes reference elements which
`support radio access, wirelinc access, switching and control,
`mobility management, and Operations, Administration,
`Maintenance and Purchasing (OAM&P). As shown in the
`schematics,
`the PCS system includes a PCS Switching
`Center (PSC) 38 which supports access independent calll
`service control and connection control (switching) functions
`and is responsible for interconnection of access and network
`systems to support end-to-cnd services. The PCS switching
`center 38 represents a collection of one or more network
`elements. The system further includes a Radio Access Sys-
`tem Controller (RASC) 40 which supports the wireless
`mobility management and wireless access call control func-
`tions. It serves one or more subtending radio port controllers
`42 and may be associated with one or more PCS switching
`centers 38. As known to those skilled in the art, Radio Port
`Controllers 42 provide an interface between one or more
`subtending Radio Port Intermediaries (RPls), a PCS switch-
`ing centcr such as PSC 38, and RASC, air interface inde-
`pendent radio frequeucy transmission and reception func-
`tions.
`
`The system further includes a Radio Port Intermediary
`(RP!) 44 which provides an interface between one or more
`subtending Radio Ports 46 and the Radio Port Controller 42,
`and supports air interface dependent radio frequency trans-
`mission and reception functions. Radio Port 46 supports the
`transmission of signals over the air interface and is provided
`in communication with Radio Personal Terminal (RPT) 48.
`This is a light-weight, pocket-size portable radio terminal
`providing the capability for the user to be either stationary
`or in motion while accessing and using telecommunication
`services.
`
`The system further includes variations of RPTs which are
`in fixed locations, termed Radio Termination (Type I) 50
`and Radio Termination (Type 2) 52, which interface Termi-
`nal Equipment (Type I) 54 and Terminal Equipment (Type
`2) S6 to the Radio Access Interface.
`
`The system of FIG. 3 further includes aTerminal Mobility
`Controller (TMC) 58 which provides the control logic for
`terminal authentication, location management, alerting, and
`routing to RPT/RT‘s. There is also provided a Terminal
`Mobility Data—store (TMD) 60 which is operative to main-
`tain data associatcd with terminals.
`
`the system includes a Personal Mobility
`Still further,
`Controller (PMC) which provides the control logic for user
`authentication, service request validation, location manage-
`ment, alerting, user access to service profile, privacy, access
`registration, and call management PMC 62 is provided in
`communication with a Personal Mobility Datu—store (PMD)
`which maintains data associated with users.
`
`Finally, the system includes Operations, Administration,
`Maintenance, and Provisioning, (OAM & P) systems 66
`which monitor,
`test, administer, and manage traflic and
`billing information for personal communications services
`and systems. PCS 38 is also provided in communication
`with Auxiliary Services 68, Interworking Functions (IWF)
`70 and External Networks 72.
`In accordance with the
`
`65
`
`5,602,903
`
`4
`above-referenced working document for Stage 2 service
`description, Auxiliary Services 68 are defined as a variety of
`services such as voice mail, paging, etc. which may not be
`provided by the PCS 38. IWF 70 are further defined as
`mechanisms which mask the differences in physical, link
`and network technologies into consistent network and user
`services. Still further, External Networks 72 are defined as
`other voice, digital data, packet data, and broadband data
`networks.
`FIG. 4 provides a unified functional model of the detailed
`system of FIG. 3. This functional model is derived from the
`PCS reference architecture in FIGS. 311-312 by aggregating
`the terminal entities (RT and R171") into a single functional
`grouping Radio Terminal Function (RTF), and aggregating
`RP, RPI, and RFC into another single functional grouping
`RCF in accordance with the ANSI Stage 2 service descrip-
`tions for PCS. The model includes Call Control Function
`(CCF) 74, Service Switching Function (SSF) 76, Service
`Control Function (SCF) 78, Service Data Function (SDF)
`80, Service Resource Function (SRP) 82, Radio Access
`Control Function (RACF) 84, Radio Control Function
`(RCF) 86, and Radio Termination Function (RTF) 88. The
`functions of the terminal elements are more fully described
`in the Stage 2 service description for PCS.
`Wireless communication services such as the above cel-
`lular and PCS systems, have been quickly embraced by
`those people whose business requires them to travel fre-
`quently and to be in constant communication with their
`clients and associates. The increased use of wireless com-
`munication services, however, have caused headaches for
`emergency operators and other position dependent service
`providers who require precise location data. As known to
`those skilled in the art, under current wireless technology,
`position data is strictly limited to relatively large coverage
`areas and sectors thereof as defined by the RF characteris-
`tics,
`i.e.
`footprints, of the associated base station As
`explained below, these coverage areas are generally unsuit-
`able for most commercial and consumer applications.
`In the late l960’s, federal legislation was enacted which
`established the 9-1-1 telephone number as a national emer-
`gency resource. In land-based systems, Enhanced 9-l-l (E
`9-1-I) wirelinc technology provides the caller’s Automatic
`Location Identification (ALI) with reasonable accuracy, cost
`and reliability, to a Public Safety Answering Point (PSAP)
`via a defacto standard. ALI is generally accomplished by
`receiving the ANI, or Automatic Number Identification,
`during call setup to the PSAP. A database query, given ANI,
`provides ALI to the emergency call taker display terminal as
`both panics establish the voice channel.
`
`Currently wireless technology, however, does not provide
`ALI. As a result, an ever-increasing percentage of emer-
`gency telephone calls can be tracked no further than the
`originating base station. As readily seen, the heart of the
`problem for providing E9-1-lALI services for wireless
`communication customers lies in accurately and reliably
`determining the mobile unit, i.e., handset location, under any
`circumstance, at low cost.
`
`there have been previous
`this background,
`Against
`attempts to provide methods and systems which generally
`identify the positions of wireless communication system
`users in cell site coverage areas and sectors thereof. See, for
`example, U.S. Pat. No. 4,876,738 issued to Selby and
`assigned to U.S. Phillips Corporation. Selby discloses a
`registration procedure in which the base station monitors the
`location of the mobile unit by cell site. The effect is to allow
`enlargement of the registration area if the mobile unit
`consistently roams between two cells.
`
`Apple Inc.
`
`Exhibit 1011
`
`Page 23
`
`

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`5,602,903
`
`5
`See also, U.S. Pat No. 5,l79,72lissucd to Comroc et al
`and assigned to Motorola, lnc. Comroe discloses a method
`for inter-operation of a cellular communication system and
`trunking communication system by transmitting an access
`number for each system such that the mobile unit may be
`used as a cellular telephone and a trunking communication
`device.
`Still further, see U.S. Pat. No. 5,097,499 issued to Con-
`sentino and assigned to AT&T Bell Laboratories. Consen-
`tino teaches amethotl for preventing an overload in a reverse
`channel by delaying the time of the generation of tinting
`stamps on markers.
`These methods and systems, however, have proven
`unsuitable for commercial and consumer applications where
`users may, at any given time, travel through very small
`portions of numerous cell site coverage areas and sectors.
`Under current wireless technolog , and as described in the
`prior art referenced above, presently available positioning
`methods and systems are limited to a determination of
`whether the user is within one or more predetermined cell
`site coverage areas or sectors. These prior art systems are
`incapable of providing further detail, i.e. exactly where in
`tbc cell site coverage area the user is located.
`Prior art attempts to design higher accuracy positioning
`systems which utilize commercial broadcast transmissions,
`for example, have also met with limited success. See, for
`example, U.S. Pat. Nos. 4,054,880 (Dalabakis et al) and
`3,889,264 (Fletcher) which disclose what are known as
`“delta-position” systems. These prior art patents describe
`systems using three spectrally spaced-apart radio signals,
`each of which is an independent AM radio signal. The
`systems typically have a vehicle carried mobile receiver,
`with a separate tuner for each station, and a second receiver
`at a fixed, known position. As disclosed, these systems count
`“zero crossing counts”, each of which indicates that the user
`has moved a certain distance from his or her previous
`location. In operation, if it is desired to determine the current
`position of the user, a starting position must first be speci-
`fied. A fixed position receiver detects frequency drift of the
`transmitters, which is used to adjust and coordinate zero
`crossing counts made by the mobile receivers.
`These systems are termed “delta-position” systems
`because they determine only the distance and direction
`traveled by a mobile user from any particular starting point.
`Neither Dalabakis et al nor Fletcher actually determines the
`position of the mobile user.
`See also, U.S. Pat. No. 5,173,710 to Kelley et al which
`discloses the use of a fixed position receiver which is
`adapted to determine frequency drift along with the relative
`phases of various unsynchronized FM broadcast signals
`originating from known fixed locations. As disclosed by
`Kelley, each of the fixed transmitters transmits a beacon
`signal having a phase that is unsynchronized with the phases
`of the beacon signals of the other transmitters. These signals
`are 19 K112 analog pilot tones generated by commercial
`broadcast sterco FM stations. The fixed receiver receives the
`beacon signals, determines the relative phases of the beacon
`signals, and broadcasts data representing these relative
`phases for receipt by the mobile receiver which is at an
`unknown location. Each mobile receiver includes phase
`measurement circuitry that detects the phases of the beacon
`signals at the mobile receiver's current position on multiple
`distinct carrier frequencies such that the current position of
`the mobile unit may be determined when used in conjunc-
`tion with the fixed receiver broadcast data.
`Sec also, U.S. Pat. Nos. 5,055,851; 4,891,650; and 5,218,
`367, all issued to E. Shelfer and assigned to Traekmobile,
`
`10
`
`20
`
`30
`
`35
`
`45
`
`50
`
`55
`
`60
`
`65
`
`6
`Inc. Like the ’65O patent, the '85] patent utilizes measure-
`ments of the mobile unit’s signal strength which is detected
`by some number of neighboring base stations in order to
`calculate location. In operation, each base station transmits
`a special packet of data which includes this information for
`receipt by the MTSC. Another packet of information, the
`actual vehicle alarm distress call (this is not the same as a
`9-1 -l call), is also sent to the MTSC. The MTSC sends these
`two information packets to a Trackrnobile alann center
`personal computer. The computer matches both packets
`using a simple algorithm in order to find the vehicle‘s
`distance from the base station cell center point. As disclosed,
`this is done preferably with four neighboring base station
`cell site measurements along with arcuation or line inter-
`section techniques. The results are displayed on a computer
`screen map. A 9-1-1 call may then be initiated by a Track-
`mobile attendant, based on a verbal request from the origi-
`nating mobile user.
`The Trackmobile ‘B67 patent operatesin much the same
`way as the ’851 and '650 patents although it uses a modified
`handset including a modem, to send signal strength mea-
`surements received at the mobile unit, through the cellular
`network to the Trackmobile alarm center. Only the downlink
`signal strengths, received at the mobile unit, are used to
`estimate location. The location is determined from the same
`algorithm as in the ’85l patent, but includes a refinement—-
`antenna sector ID-——if known. As disclosed, the sector ID
`information reduces error by cfiectivcly slicing the cell
`circle into one of three pie—shaped sections. In the case of
`low power PCS installations, it is likely that omnidirectional
`antennas would be used,
`thus precluding the use of this
`sector refinement.
`
`None of the systems referenced above, as well as general
`time difference of arrival location systems such as LORAN,
`NAVSTAR, and GPS. as used for example in U.S. Pat. No.
`4,833,480, issued to Palmer at al, have proven suitable for
`commercial applications since, by design, they require spe-
`cially adapted receivers to receive and process the pilot
`tones, GPS signals, etc. at the mobile unit. This sophisticated
`end equipment, of course, significantly adds to the cost of
`the corresponding mobile unit. In the case of hand portable
`units, this additional equipment further results in a handset
`which is extremely bulky and difficult to handle. As a result,
`these systems have proven unsuitable for both large scale
`commercial applications, as well as ordinary consumer use.
`When applied to wireless communications of interest to
`the present invention, i.e. communications in the frequency
`band from 800 MHz to 2.5 GHz, these prior art systems are
`further considered unsuitable for commercial applications in
`View of their anticipated use of excessive frequency spec-
`trum. More specifically,
`it
`is anticipated that for proper
`operation, these systems would necessarily require trans-
`mission of signals on separate channels which would utilize
`an unacceptable amount of additional spectrum.
`The prior art systems also fail to account for changes in
`environmental conditions. For GPS receivers, it is known to
`those skilled in the art that the location calculation will not
`work unless there is a clear view of at least 3-4 satellites. In
`dense urban areas, especially at the street level, this condi-
`tion could easily prcvail as potential users move about in the
`environment, Thus, no location estimate would be available
`if less than three satcllitc signals can be received.
`In many ofiice buildings, the metal content of the win-
`dows is also suflicient to preclude effective satellite recep-
`tion. To this end, if all wireless antennas were isotropic and
`were located in flat and open terrain, estimating the location
`
`Apple Inc.
`
`Exhibit 1011
`
`Page 24
`
`

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`7
`
`5,602,903
`
`of a handset using the prior art strength technology might be
`sufiicient. Unfortunately.
`the known disadvantage of the
`PCS world, and to a reasonable extent, cellular, is that they
`do not operate in flat and open terrains. None of the prior an
`patents work in areas where there are obstructions to the
`radio signal’s path like buildings, trees, hills, and automo-
`biles, Seasons are also known to have a dramatic aflfect on
`propagation where radio waves are significantly attenuated
`by tree leaves in the summer, but less so in the winter. Thus,
`actual RF field data gathered in one season may not be
`accurate in another season.
`
`I0
`
`As readily seen, precisely predicting location based on RF
`propagation loss has generally been an intractable problem,
`due to the complexity of factors, as well as the data
`collection difliculties in constructing the necessary data-
`bases needed to supply the actual
`field data. Thus,
`the
`principles relied upon by the above-referenced patents, such
`as free space loss or clear access to satellites, rarely exists,
`as obstructions and interference increases daily, even in the
`most optimal RF environments.
`Consequently, a need has developed to provide a posi-
`tioning system and method which may be practically and
`economically implemented for use in wireless communica-
`tion systems and, in particular, in the frequency band from
`800 MHz to 2.5 GHz.
`
`Still further, a need has developed to provide such a
`positioning system which may be used by service providers
`t