United States Patent [19J
`Coursey
`
`I 1111111111111111
`
`
`11111 111111111111111 IIIII 1111111111 11111 111111111111111111
`US005950130A
`[11] Patent Number:
`[45] Date of Patent:
`
`5,950,130
`Sep.7,1999
`
`[54]
`
`MOBILE STATION WITH INTELLIGENT
`ROAMING AND OVER-THE-AIR
`PROGRAMMING FEATURES
`
`Release Notes, Recommendation GSM 02.11-DCS, Service
`Accessibility, Version 3.0.1, Release 92, Phase 1, Released
`by ETSI/PT12 12 V, Feb. 1992.
`
`[75]
`
`Inventor: Cameron Kelly Coursey, Austin, Tex.
`
`[73]
`
`Assignee: SBC Technology Resources, Inc.,
`Austin, Tex.
`
`[21]
`
`Appl. No.: 08/828,172
`
`[22]
`
`Filed:
`
`Mar. 18, 1997
`
`[51]
`[52]
`[58]
`
`[56]
`
`Int. Cl. 6
`H04Q 7/22
`.......................................................
`U.S. Cl. ........................... 455/432; 455/419; 455/552
`Field of Search
`..................................... 455/432-435,
`455/461, 550---552, 403, 422, 426, 419,
`418
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`4,916,728
`5,020,091
`5,093,926
`5,101,500
`5,159,625
`5,276,905
`5,297,191
`5,297,192
`5,301,223
`5,357,561
`5,428,666
`5,442,806
`5,463,675
`5,504,803
`5,524,135
`5,551,058
`5,615,248
`5,642,398
`5,734,980
`5,761,618
`
`4/1990 Blair .
`5/1991 Krolopp et al. .
`3/1992 Sasuta .
`3/1992 Marni .
`10/1992 Zicker .
`1/1994 Hurst et al. .
`3/1994 Gerszberg .
`3/1994 Gerszberg .
`4/1994 Amadon et al. .
`10/1994 Grube .
`6/1995 Fyfe et al. .
`8/1995 Barber et al. .
`10/1995 Gerszerg .
`4/1996 Yamada et al. .
`6/1996 Mizikovsky et al. .
`8/1996 Hutcheson et al. .
`3/1997 Norimatsu ............................... 455/566
`6/1997 Tiedemann, Jr. et al. .......... 455/435 X
`3/1998 Hooper et al. .......................... 455/434
`6/1998 Lynch et al. ............................ 455/419
`
`OIBER PUBLICATIONS
`
`Update Note, Recommendation GSM 02.11, Service Acces(cid:173)
`sibilty, Version 3.7.0, Released by ETSI/PT12, Nov. 1992.
`Document Change Control Record, Recommendation GSM
`02.11-DCS, Service Accessibility, Version 3.1.0, Released
`by ETSI/PT12, Nov. 1992.
`
`Stage 1 Description for System Selection for Pref erred
`Roaming, Version 1.7, Telecommunications Industries Asso(cid:173)
`ciation (TIA), TR45.5 Sub-Committee, Santa Barbara, CA,
`Feb. 9, 1996.
`
`System Selection for Preferred Roaming/Stage 2 & 3
`Description, Version 1.2, Telecommunications
`Industries
`Association (TIA), Enhanced Roaming Team, Feb. 9, 1996.
`
`Primary Examiner-Dwayne D. Bost
`Assistant Examiner-William G. Trost
`Attorney, Agent, or Firm----Greenblum & Bernstein P.L.C.
`
`[57]
`
`ABSTRACT
`
`A method of intelligent roaming wherein a Systems Access
`List (SAL), programmed
`into the memory of a mobile
`station over-the-air or via a physical interface, is used to
`select a preferred system for service. When the mobile
`station is powered on, it scans the home band first, then a
`secondary band if a control channel is not found on the home
`band. If the mobile station determines that it is located in its
`home system, it remains on that band and obtains service
`from the home system. If the mobile station is not located
`within its home system, the SAL is searched to determine if
`there is a preferred system in the same area as the current
`system. If not, then the mobile station obtains service on the
`current system. If the SAL indicates there is a preferred
`system in the same area as the current system, then the SAL
`also indicates the exact band(s) where a preferred system
`may be located. The SAL may include information on the
`blocks of channels to scan. The SAL may indicate the air
`interface technology supported on each of the preferred
`bands, to assist the mobile station in finding a system of a
`given technology type. The SAL may include information
`for the mobile station to use in determining whether to
`display a roaming indicator and/or an alphanumeric name
`when operating on a given system.
`
`73 Claims, 12 Drawing Sheets
`
`Dell Inc., Ex. 1024
`Page 1 of 34
`
`

`

`U.S. Patent
`
`Sep.7,1999
`
`Sheet 1 of 12
`
`5,950,130
`
`co ,.,,,
`
`~:z:
`...JO co i=
`oc::c
`~t;::;
`
`0 .....
`
`1-(cid:173)
`~
`
`:z:
`1-(cid:173)......
`c....
`
`0 .....
`
`1-(cid:173)
`~
`
`Dell Inc., Ex. 1024
`Page 2 of 34
`
`

`

`U.S. Patent
`
`Sep.7,1999
`
`Sheet 2 of 12
`
`5,950,130
`
`00 '°
`
`r(cid:173)
`-.0
`
`u.J :z:
`---1 0
`cii:ii=
`Oj5
`::E:...,..
`
`l~..;__J
`0~
`I ::E: -~~
`
`L-
`
`<(
`C\J
`
`(!)
`
`LL
`
`0 ......
`1-(cid:173)
`::E:
`
`r1
`
`,......
`/Y'\
`
`:z:
`I-(cid:173).....
`
`Q..
`
`r1
`
`,......
`M
`
`0 ......
`1-(cid:173)
`::E:
`
`Dell Inc., Ex. 1024
`Page 3 of 34
`
`

`

`U.S. Patent
`
`Sep.7,1999
`
`Sheet 3 of 12
`
`5,950,130
`
`FIG. 2B
`
`62
`
`DISPLAY ~
`
`(
`----~65
`
`KEYPAD
`
`IMEMORY I
`
`I W/SAL ~
`L.---..1
`\
`'-67
`
`(_~.~=========-=-)
`r
`69
`
`Dell Inc., Ex. 1024
`Page 4 of 34
`
`

`

`U.S. Patent
`
`Sep.7,1999
`
`Sheet 4 of 12
`
`5,950,130
`
`FIG. 2C
`
`62
`
`63
`
`68~
`
`ANTENNA
`
`64
`SPEAKER
`
`TRANSCEIVER
`
`DISPLAY
`
`65
`
`CONTROL SYSTEM
`
`61
`
`66
`
`KEYPAD
`
`67
`MEMORY
`W/SAL
`
`69
`MICROPHONE
`
`Dell Inc., Ex. 1024
`Page 5 of 34
`
`

`

`U.S. Patent
`
`Sep.7,1999
`
`Sheet 5 of 12
`
`5,950,130
`
`FIG. 3
`S.2
`
`INITIALIZATION STATE
`
`S.4
`
`SCAN HOME BAND
`
`YES
`
`S.8
`OBTAIN SERVICE
`FROM HOME SYSTEM
`
`S.14
`
`YES
`
`OBTAIN SERVICE
`FROM CURRENT SYSTEM
`
`S.10
`SEARCH SAL FOR
`CURRENT SYSTEM
`
`NO
`
`S.16
`OBTAIN SERVICE
`FROM BAND(S)
`INDICATED BY ~AL
`
`Dell Inc., Ex. 1024
`Page 6 of 34
`
`

`

`U.S. Patent
`
`Sep.7,1999
`
`Sheet 6 of 12
`
`5,950,130
`
`FIG. 4
`
`S.20
`SID
`CHANGE
`
`S.28
`POWER
`ON
`
`S.32
`NO SERVICE
`
`S.34
`IR MODE
`SELECTED
`
`NO
`
`NO
`
`YES
`
`USE NORMAL
`
`PREFERRED SYSTEM
`
`SELECTION LOGIC
`
`S.36
`
`SCAN HOME BAND
`FOR CCh
`
`NO
`
`YES
`
`NO
`
`S.40
`
`SCAN SECONDARY
`BAND FOR CCh
`
`NO
`
`S.44
`DISPLAY
`NO SERVICE
`INDICATION
`
`Dell Inc., Ex. 1024
`Page 7 of 34
`
`

`

`U.S. Patent
`
`Sep.7,1999
`
`Sheet 7 of 12
`
`5,950,130
`
`FIG. 5
`
`S.58
`P_Scan=O
`
`S.60
`
`CHECK SID
`AGAINST SAL
`
`S.50
`P _Scan=O
`
`S.52
`COMPLETE
`
`INITIALIZATION TASK OR
`CONTROL CHANNEL
`
`SELECTION PROCEDURE
`
`S.72
`COMPLETE
`
`INITIALIZATION TASK OR
`CONTROL CHANNEL
`
`SELECTION PROCEDURE
`
`DISPLAY
`ROAM
`INDICATOR &
`ROAMING SID
`ALPHA TAG
`
`COMPLETE
`
`INITIALIZATION TASK OR
`CONTROL CHANNEL
`
`SELECTION PROCEDURE
`
`NO
`
`Dell Inc., Ex. 1024
`Page 8 of 34
`
`

`

`U.S. Patent
`
`Sep.7,1999
`
`Sheet 8 of 12
`
`5,950,130
`
`FIG. 6
`
`NO
`
`S.76
`
`P Scan= I
`S Count=O
`T Scan=2 1/2 min
`- OR 5 min
`
`YES
`
`NO
`
`INCREMENT
`S Count
`
`YES
`S.86
`
`CHOOSE NEXT
`TARGET SYSTEM
`
`S.88
`FOR THE TARGET BAND,
`SCAN THOSE CHANNELS
`
`IDENTIFIED IN THE
`
`PROBABILITY BLOCK
`MAP FOR ACCs OR
`DCCHs, AS INDICATED
`BY THE TECHNOLOGY
`MAP
`
`NO
`
`Dell Inc., Ex. 1024
`Page 9 of 34
`
`

`

`U.S. Patent
`
`Sep.7,1999
`
`Sheet 9 of 12
`
`5,950,130
`
`FIG. 7
`
`S.94
`
`ENTER IDLE STATE OR
`
`DCCH CAMPING STATE
`ON THIS SYSTEM
`
`NO
`
`NO
`
`NO
`
`S.104
`
`WAIT FOR MS TO
`
`RE-ENTER IDLE OR
`CAMPING STATE
`
`YES
`
`Dell Inc., Ex. 1024
`Page 10 of 34
`
`

`

`U.S. Patent
`
`Sep.7,1999
`
`Sheet 10 of 12
`
`5,950,130
`
`FIG. 8
`
`MS
`
`Configuration Data Request
`...
`
`BMI
`
`S.200
`
`_..
`-
`
`~
`
`-
`
`~
`
`~
`
`S.204
`
`S.212
`
`S.220
`
`S.228
`
`S.236
`
`Download Request
`
`NAM Commit Request
`
`CSC Challenge Response
`
`...
`
`~
`
`CSC Challenge Request . .
`
`CSC Challenge Response
`
`Configuration Data Response
`
`. .
`
`S.208
`
`S.216
`
`S.224
`
`S.232
`
`Download Result . .
`
`CSC Challenge Request . -
`
`NAM Commit Result . -
`
`Dell Inc., Ex. 1024
`Page 11 of 34
`
`

`

`U.S. Patent
`
`Sep.7,1999
`
`Sheet 11 of 12
`
`5,950,130
`
`MS
`
`.... SOC Specific Request
`-
`
`BMI
`
`S.300
`
`FIG. 9
`
`Potential multiple instances
`of SOC Specific Request
`
`•
`
`•
`
`•
`
`_ SOC Specific Request
`
`_ NAM Commit Request
`-
`
`- CSC Challenge Response
`-
`
`S.312
`
`S.320
`
`S.304
`
`S.308
`
`S.316
`
`CSC Challenge Request _ .
`
`NAM Commit Result
`
`-.
`
`Dell Inc., Ex. 1024
`Page 12 of 34
`
`

`

`U.S. Patent
`
`Sep.7,1999
`
`Sheet 12 of 12
`
`5,950,130
`
`FIG. 10
`
`192
`
`MASTER SAL
`
`
`
`186 OTAF/SLAVE SAL----------
`
`MTSO
`
`154
`
`175
`
`168
`
`Dell Inc., Ex. 1024
`Page 13 of 34
`
`

`

`5,950,130
`
`1
`MOBILE STATION WITH INTELLIGENT
`ROAMING AND OVER-THE-AIR
`PROGRAMMING FEATURES
`
`BACKGROUND OF THE INVENTION
`
`1. Field of the Invention
`The present invention relates to the field of telecommu(cid:173)
`nications. More particularly, the present invention relates to
`cellular or Personal Communications Services (PCS) net(cid:173)
`work systems, and mobile stations having intelligent roam(cid:173)
`ing and over-the-air programming features.
`2. Acronyms
`The written description provided herein contains acro(cid:173)
`nyms which refer to, for example, various telecommunica(cid:173)
`tion services, components and techniques, as well as features
`relating to the present invention. Although some of these
`acronyms are known, use of these acronyms is not strictly
`standardized in the art. For purposes of the written descrip(cid:173)
`tion herein, acronyms will be defined as follows:
`Advanced Mobile Phone Service (AMPS)
`Analog Control Channel (ACC)
`Base Station/Mobile Switching Center/Interworking
`Function (BMI)
`Code Division Multiple Access (CDMA)
`Complimentary Metal Oxide Semiconductor (CMOS)
`Control Channel (CCh)
`Customer Service Center (CSC)
`Digital Control Channel (DCCH)
`Digital Traffic Channel (DTC)
`Electronically
`Erasable Programmable Read Only
`Memory (EEPROM)
`Federal Communications Commission (FCC)
`Group System for Mobile Communications (GSM)
`Home Location Register (HLR)
`International Mobile Station Identity (IMSI)
`Intelligent Roaming Mode (IR Mode)
`Interim Standard (IS)
`Liquid Crystal Display (LCD)
`Mobile Identification Number (MIN)
`Mobile Station (MS)
`Mobile Switching Center (MSC)
`Mobile Telephone Switching Office (MTSO)
`Number Assignment Module (NAM)
`Over-the-Air Activation Function (OTAF)
`Over-the-Air Activation Teleservice (OATS)
`Personal Access Communication System (PACS)
`Personal Communications Network (PCN)
`Personal Communications Services (PCS)
`Public Land Mobile Network (PLMN)
`Public Switched Telephone Network (PSTN)
`Random Access Memory (RAM)
`System Access List (SAL)
`System Identification Code (SID)
`System Operator Code (SOC)
`Transmission Control Protocol/Internet Protocol (TCP/
`IP)
`Time Division Multiple Access (TDMA)
`3. Background and Material Information
`The use of wireless or mobile communication devices has
`increased greatly in recent years. Mobile and cellular tele-
`
`2
`phones have enabled mobile station users to roam over large
`geographic areas while maintaining
`immediate access to
`telephony services. Mobile stations include portable units,
`units installed in vehicles and fixed subscriber stations.
`5 Mobile stations comprising cellular telephones or wireless
`handsets are operable in cooperation with cellular or Per(cid:173)
`sonal Communications Services (PCS) communications sys(cid:173)
`tems. Cellular communication systems typically provide
`service to a geographic area by dividing the area into many
`10 smaller areas or cells. Each cell is serviced by a radio
`transceiver (i.e., a transmitter-receiver base station or cell
`site). The cell sites or base stations may be connected to
`Mobile Telephone Switching Offices (MTSOs) or Mobile
`Switching Centers (MSCS) through landlines or other com-
`15 munication links, and the MTSOs may, in turn, be connected
`via landlines to the Public Switched Telephone Network
`(PSTN).
`FIG. 1 illustrates the basic components of a conventional
`cellular network. As shown in FIG. 1, a mobile station 38
`20 may place or receive calls by communicating with a cell site
`30 or a cell site 40, depending upon the geographic location
`of the mobile station and the cell coverage area that is
`provided by each cell site (i.e., cell coverage area 35 of cell
`site 30 or cell coverage area 45 of cell site 40). For purposes
`25 of illustration, mobile station 38 is depicted in FIG. 1 as
`being able to communicate with either cell site 30 or cell site
`40, even though the mobile station is not illustrated as being
`located within cell coverage area 35 or cell coverage area 45.
`Under normal operating conditions,
`the extent to which
`30 mobile station 38 will be able to communicate with cell site
`30 or cell site 40 will depend on the geographic location of
`the mobile station and the size of the cell coverage area of
`each cell site. Further, although only two cell sites are
`depicted in FIG. 1, the entire cellular network may include,
`35 for example, more than two cell sites. In addition, more than
`one cell site may be connected to each MTSO.
`Mobile station 38 may include a conventional cellular
`telephone unit with a transceiver and antenna (not shown) to
`communicate by, for example, radio waves with cell sites 30
`40 and 40. Various air-interface technologies may be imple(cid:173)
`mented to facilitate communication between the mobile
`station and the cell sites. Cell sites 30 and 40 may both
`include a radio transceiver (not shown) and be connected by
`landlines 16 or other communication links to MTSOs 24 and
`45 28. The PSTN 12 is also connected to each MTSO 24 and
`28 by landline 16 or other communication links.
`The MTSOs 24 and 28 may be conventional digital
`telephone exchanges that control the switching between
`PSTN 12 and the cell sites 30 and 40 to provide wireline-
`50 to-mobile, mobile-to-wireline and mobile-to-mobile call
`connectivity. The MTSOs 24 and 28 may also (i) process
`mobile station status data received from the cell site con(cid:173)
`trollers; (ii) handle and switch calls between cells; (iii)
`process diagnostic information; and (iv) compile billing
`55 information. The transceiver (not shown) of each cell site 30
`and 40 provides communications, such as voice and data,
`with mobile station 38 while it is present in its geographic
`domain. The MTSOs 24 and 28 may track and switch mobile
`station 38 from cell site to cell site, as the mobile station
`60 passes through various coverage areas. When mobile station
`38 passes from one cell to another cell, the MTSO of the
`corresponding cell may perform a "hand-off' that allows the
`mobile station to be continuously serviced.
`In the current North American cellular system, any given
`65 area may be serviced by up to two competing service
`providers of cellular air time communication services. By
`Federal Communications Commission (FCC) regulations,
`
`Dell Inc., Ex. 1024
`Page 14 of 34
`
`

`

`5,950,130
`
`3
`the two competing service providers are assigned different
`groups of frequencies through which services are provided.
`A frequency set typically
`includes control channels and
`voice channels. The control channels are used for prelimi(cid:173)
`nary communications between a mobile station and a cell 5
`site for setting up a call, after which a voice channel is
`assigned for the mobile station's use on that call. The
`assigned frequency sets are generally referred to as "A band
`frequencies" and "B band frequencies". Typically, the A
`band frequencies are reserved for non-wireline service
`providers, while the B band frequencies are reserved for
`wireline service providers. While each frequency set for a
`given cellular service area is assigned to only one service
`provider, in different service areas the same frequency set
`may be assigned to different service providers or companies.
`Depending upon which service provider is subscribed to
`by the user of the mobile station, the home frequency set of
`the user may correspond to the A frequency band or the B
`frequency band. Whenever a call is placed by the mobile
`station, the unit will ordinarily attempt to use the home 20
`frequency set to establish the call. If a call is handled outside
`of the user's home network area, then the unit is said to be
`"roaming" and service will be attempted through a fre(cid:173)
`quency set of a non-home service provider. Typically, the
`user's home service provider will have a roaming agreement 25
`or -reciprocal billing arrangement with the non-home ser(cid:173)
`vice provider to permit service to be extended to the user's
`mobile unit when it is roaming in the non-home service
`provider's service area.
`The mobile station may include a memory device, such as 30
`a number assignment module (NAM), in which an assigned
`phone number and a system identification code (SID) is
`stored to uniquely identify the home service provider for the
`unit. In the North American cellular system, each cellular
`market or provider is assigned a distinct, fifteen bit SID. In 35
`Europe, on the other hand, the Global System for Mobile
`Communications (GSM) standard (see, for example, Rec(cid:173)
`ommendation GSM 02.11, Service Accessibility, European
`Telecommunications Standards Institute, 1992) defines a
`process for network selection based on the mobile station 40
`reading the GSM equivalent of the SID, called the Public
`Land Mobile Network (PLMN) identity. The SID or equiva(cid:173)
`lent system
`identification number
`is broadcast by each
`service provider or cellular provider and is used by the
`mobile station to determine whether or not the mobile 45
`station is operating in it's home network or if it is operating
`in a roaming condition. The mobile station makes this
`determination by reading the SID that is broadcasted in the
`cellular market in which it is located, and comparing it to the
`home SID stored in the NAM of the cellular phone unit. If
`the SIDs do not match, then the mobile station is roaming,
`and the mobile station must attempt to gain service through
`a non-home service provider. Due to the imposition of a
`fixed surcharge or higher per unit rate, the air time charges
`when the mobile station is roaming are customarily higher 55
`than when it is operating within its home network.
`Operation under a roaming condition is often under the
`control of the mobile station user. The user can select
`whether the mobile station will operate in a Home System
`Only, A Band Only, B Band Only, A Band Preferred, or B
`Band Preferred operating mode. The user typically controls
`the system preference and mode operation through menu
`choice or selection. This current method of roaming control
`is conventionally known as "Preferred System Selection". In
`the most common roaming situation,
`the mobile station
`remains on the same band as the home cellular network. That
`is, if the mobile station is homed to a cellular network with
`
`4
`an odd numbered SID (which is normally assigned to an A
`band cellular service provider), then the mobile station will
`obtain service from the A band cellular service provider
`when roaming.
`Occasionally, the home service provider will program a
`mobile station with negative SIDs. Negative SIDs corre(cid:173)
`spond to SIDs on which the mobile station should not obtain
`service. Negative SIDs may be used, for example, if roaming
`agreements are not in place between different cellular ser-
`10 vice providers. An example of a mobile station that utilizes
`negative SIDs is disclosed in BLAIR, U.S. Pat. No. 4,916,
`728. As an alternative
`to negative SIDs, some mobile
`stations are programmed with positive or preferred SIDs.
`Positive or preferred SIDs are SIDs on which the mobile
`15 station should attempt to obtain service when selecting a
`cellular carrier frequency. An example of a mobile station
`that utilizes preferred SIDs is disclosed in BARBER et al.,
`U.S. Pat. No. 5,442,806. The use of preferred SIDs facilitate
`the selection of a preferred service provider when the mobile
`station is roaming.
`Presently, there is a need in the cellular and mobile
`network industries to provide some form of "intelligent" or
`"automatic" roaming in which the mobile station obtains
`service on the cellular network with which the home cellular
`service provider has the best roaming agreement ( or the
`cellular service provider's own network in the roaming area,
`if it is not in the same band as the home system). There are
`three factors that have primarily led to this need. First, large
`cellular service providers rarely operate in the same band in
`all markets. Secondly, cellular service providers have chosen
`to implement three distinct technologies at 800 MHz (i.e.,
`Analog Only, Time Division Multiple Access (TDMA), and
`Code Division Multiple Access (CDMA)), and the mobile
`station may have to change bands to obtain service on the
`preferred technology. Third, with the advent and develop(cid:173)
`ment of Personal Communications Services (PCS), there is
`an increasing desire for roaming to, for example, 1900 MHz
`PCS systems.
`As will be appreciated by those skilled in the art, PCS
`covers a broad range of individualized telecommunication
`services that let users communicate
`irrespective of where
`they are located. With PCS, personalized numbers are
`assigned to individuals rather than to the mobile stations,
`and call completion is performed regardless of the location
`of the user. PCS may be implemented through conventional
`macrocellular techniques or through Personal Communica-
`tions Networks (PCN) that utilize light, inexpensive hand(cid:173)
`held handsets and communicate via low-power antennas that
`are intended to operate in a similar fashion to that of large
`50 scale cellular telephone networks, but operate within small
`geographic or microcellular areas. It is anticipated that PCNs
`will operate within the same frequency band in most coun(cid:173)
`tries (e.g., 1850---1990 Mhz), while cellular systems will
`operate in different frequency bands in various countries.
`In the marketplace today, there is also a need to provide
`intelligent roaming capabilities in order to reduce scanning
`and acquisition time, and to permit a mobile station to more
`quickly determine which system it should obtain service on
`prior to registration. In conventional systems,
`including
`60 systems that utilize negative or preferred SIDs, the mobile
`station will typically scan a plurality or all of the available
`frequency bands before determining the preferred carrier for
`a present service locality. It would be desirable to provide
`intelligent
`roaming capabilities
`for a mobile station
`to
`65 reduce the time and amount of scanning that is required by
`the mobile station when seeking a non-home network ser(cid:173)
`vice provider. Prior systems do not provide, for example,
`
`Dell Inc., Ex. 1024
`Page 15 of 34
`
`

`

`5,950,130
`
`25
`
`30
`
`5
`in the mobile station to efficiently
`sufficient intelligence
`direct the mobile station to the particular band or bands
`where the mobile station may obtain service on a preferred
`system when it is roaming.
`Further, there is a need to provide intelligent roaming 5
`capabilities for a mobile station which will not require any
`changes to present network interface standards (e.g. IS-41)
`or air interface standards ( e.g., IS-136, IS-91A, IS-95), and
`which is independent of air interface technologies ( e.g.,
`Advanced Mobile Phone Service (AMPS), TDMA, CDMA, 10
`Personal Access Communication System (PACS) and PCS-
`1900 MHz). Such features are desirable in order to permit
`new intelligent roaming capabilities to be readily utilized by
`a mobile station and to allow seamless integration of such
`capabilities without modification to present industry stan- 15
`dards. For more information on network interface standards
`such as Interim Standard 41 (IS-41), see, for example,
`Cellular Radiotelecommunications
`TINEIA-IS-41.5-C,
`Intersystem Operations: Signaling Protocols, Telecommu(cid:173)
`nications Industry Association, February 1996. For more 20
`information on air-interface standards such as Interim Stan(cid:173)
`dards 95 and 136 (IS-95 and IS-136), see, for example,
`TINEIA-IS-95-A, Mobile Station-Base Station Compatibil-
`ity Standard for Dual-Mode Wideband Spread Spectrum
`Cellular
`Systems,
`Telecommunications
`Industry
`TDMA
`Association, May 1995; TINEIA-IS-136.1-A,
`Cellular/PCS-Radio Interface-Mobile Station-Base Station
`Compatibility-Digital Control Channel, Telecommunica(cid:173)
`tions Industry Association, October 1996; TINEIA-IS-
`136.2-A, TDMA Cellular/PCS-Radio
`Interface-Mobile
`Station-Base Station Compatibility-Traffic Channels and
`FSK Control Channel, Telecommunications
`Industry
`Association, October 1996; and TINEIA/IS-136.1-A-1,
`Addendum No. 1 to TIA/EIA/IS-136.l-A, Telecommunica(cid:173)
`tions Industry Association, November 1996.
`Another desirable feature is to provide over-the-air pro(cid:173)
`gramming of a mobile station to permit reprogramming of
`the mobile station with new intelligent roaming information
`as it becomes available. Such a feature would permit the
`"intelligence" that is incorporated into the mobile station to 40
`be updated and stored with ease, without requiring the user
`to bring the mobile station to a technician or operator for
`reprogramming.
`SUMMARY OF THE INVENTION
`In view of the foregoing, the present invention, through
`one or more of its various aspects, embodiments and/or
`specific features or subcomponents thereof, is thus intended
`to bring about one or more of the objects and advantages as
`discussed below.
`An object of the present invention is to provide a mobile
`station having intelligent roaming capabilities, such that the
`mobile station can readily obtain service on a preferred
`system when its home network system is not available.
`Another object of the present invention is to program a
`mobile station with sufficient intelligence
`to allow the
`mobile station to rapidly obtain service on a preferred
`cellular or PCS system when there are multiple bands and
`multiple technologies available.
`Still another object of the present invention is provide a
`mobile station with a System Access List (SAL) that directs
`the mobile station to the exact band or bands where a
`preferred system may be located. Further, an object of the
`present invention is to provide an SAL that includes infor(cid:173)
`mation on the air interface technology on each preferred
`band to assist the mobile station in finding a system of a
`given technology type.
`
`6
`Yet another object of the present invention is to reduce the
`amount of scanning required by a mobile station when
`operating in a "roaming" state. An object of the present
`invention is to provide a mobile station that has sufficient
`intelligent roaming capabilities, such that the mobile station
`is capable of readily obtaining service on the cellular or PCS
`network system with which its home system has the best
`roaming agreement or billing arrangement.
`Another object of the present invention is to provide an
`intelligent roaming process, wherein a System Access List
`(SAL) is searched by a mobile station when the mobile
`station is not operating in its home system, and wherein the
`SAL indicates the band(s) and/or channel(s) where the
`mobile station can scan and locate a preferred system when
`the current system is not a preferred system for that area. The
`SAL may also contain information for the mobile station to
`use in determining whether to display a roam icon or
`indicator, and what alphanumeric system name to display
`when operating in a given system.
`Further, an object of the present invention is to provide a
`mobile station having over-the-air programming capabili(cid:173)
`ties. According to an object of the invention, the over-the-air
`programming capabilities may allow a System Access List
`(SAL), containing intelligence for roaming, to be stored and
`updated in memory of a mobile station by interfacing with
`the mobile station over the air.
`According to one embodiment of the present invention, a
`mobile station is provided with intelligent roaming capa(cid:173)
`bilities. The mobile station, which may be implemented as
`a mobile, cellular or PCS telephone unit, includes a System
`Access List (SAL) that is stored in a memory of the mobile
`station. When the mobile station is initialized ( e.g., when the
`mobile station is powered ON, changes systems or SID area,
`operates in a "No Service" condition, or an Intelligent
`35 Roaming mode (IR Mode) is selected), the mobile station
`first scans the band of its home system. If the mobile station
`determines that it is located in its home system ( e.g., by
`analyzing the SID of the current system), the mobile station
`remains on that band and obtains service from the home
`system. If the mobile station cannot find a control channel on
`the home band, then it may scan a secondary band in which
`the mobile station is guaranteed to find a control channel.
`If the mobile station finds a control channel on its home
`band (but not in its home system) or the secondary band, the
`45 SAL is searched to determine whether the current system is
`a preferred system. This may be performed by comparing
`the SID of the current system with the entries and informa(cid:173)
`tion in the SAL. If the SAL indicates that the current system
`is a preferred system, then the mobile station obtains service
`50 on the current system. If the current system is not the
`preferred system, then the SAL indicates or directs the
`mobile station to the exact band or bands where a preferred
`system may be located for that area. The SAL may also
`indicate the air interface technology supported on each of
`55 the preferred bands to assist the mobile station in finding a
`system of a given technology type.
`According to an aspect of the present invention, the SAL
`that is stored in the mobile station may include information
`on the blocks of channels to scan in the preferred bands. The
`60 SAL contains sufficient intelligence to direct the mobile
`station to the exact band(s) and/or channel(s) where the most
`preferred systems are located when the mobile station is
`roaming. As a result, the mobile station may quickly obtain
`service on the preferred system in any area where there is
`65 cellular or PCS coverage.
`According to an aspect of the invention, an intelligent
`roaming process is provided for enabling a mobile station to
`
`Dell Inc., Ex. 1024
`Page 16 of 34
`
`

`

`5,950,130
`
`5
`
`7
`locate a preferred system within a communication network
`when a home system of the mobile station is not available.
`The communication network may comprise a plurality of
`service areas, wherein each of the service areas are assigned
`a system identification number. The intelligent roaming
`process may include: accessing, when the home system is
`not available, a system access list (SAL) stored in the mobile
`station; comparing a system identification number of the
`current service area to the SAL to determine if a preferred
`system exists for the current service area; and identifying,
`when a preferred system is determined
`to exist for the
`current service area, a frequency band where the mobile
`station can locate the preferred system for the current service
`area.
`The SAL may include a plurality of entries indicating a
`system identification number and corresponding frequency
`band for each preferred system. The entries of the SAL may
`also include air interface technology information that indi(cid:173)
`cates the air interface technology used by each preferred
`system. According to the intelligent roaming process of the 20
`invention, the entries of the SAL may be searched based on
`the system identification number of the current service area,
`and a preferred system may be determined to exist when a
`system identification number of one of the entries corre(cid:173)
`sponds to the system identification number of the current 25
`service area. When a preferred system is determined not to
`exist for the current service area, a "No Service" indication
`may be displayed to the mobile station user.
`According to another aspect of the invention, the intelli(cid:173)
`gent roaming process may further comprise scanning a home 30
`frequency band for a control channel and additionally
`scanning, when a control channel is not located on the home
`frequency band, a secondary frequency band where the
`mobile station can locate a control channel. The intelligent
`roaming process may also include programming the mobile 35
`station with the SAL over-the-air with a wireless interface,
`wherein the over-the-air programming includes storing the
`SAL in a memory of the mobile station. In order to perform
`the SAL information may be
`over-the-air programming,
`transmitted as information elements that are made part of an 40
`Over-the-Air Activation Teleservice (OATS). Over-the-air
`programming may also be achieved by embedding the SAL
`information within a System Operator Code (SOC) Specific
`Request message defined for OATS.
`In accordance with another aspect of the present 45
`invention, a process for selecting a preferred system within
`a communication network may be provided, wherein the
`process includes: scanning a home band to locate a control
`channel; obtaining, when the control channel is located, a
`system identification number corr