PCT
`
`International Bureau
`WORLD INTELLECTUAL PROPERTY ORGANIZATION
`
`
`
`INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)
`
`
`(51) International Patent Classification 5 :
`26 November 1992 (26.11.92)
`
` (43) International Publication Date:
`H04Q 7/00
`
`(11) International Publication Number:
`
`W0 92/21214
`
`(21) International Application Number:
`
`PCT/US92/02536
`
`(22) International Filing Date:
`
`30 March 1992 (30.03.92)
`
`(74) Agents: NICHOLS, Daniel, K. et 211.; Motorola, Inc., In-
`tellectual Property Department, 8000 West Sunrise
`Boulevard, Ft. Lauderdale, FL 33322 (US).
`
`(30) Priority data:
`703,428
`
`17 May 1991 (17.05.91)
`
`US
`
`(71) Applicant: MOTOROLA, INC. [US/US]; 1303 E. Algon-
`quin Road, Schaumburg, IL 60196 (US).
`
`; 9324 N.W. 18th Street,
`(72) Inventors: PATSIOKAS, Stelios, J.
`Plantation, FL 33322 (US). D’AMICO, Thomas, V.
`g
`2707 North Ocean Boulevard #302, Boca Raton, FL Published
`33431 (US). SUTER, Charles, D.
`; 4408 Main Street,
`With international search report.
`Lake Worth, FL 33461 (US). POMBO, Raul, A. ; 8361-D
`Trent Court, Boca Raton, FL 33433 (US).
`
`(81) Designated States: AT (European patent), AU, BE (Euro-
`pean patent), BR, CA, CH (European patent), DE, DE
`(European patent), DK (European patent), ES (Euro-
`pean patent), FI, FR (European patent), GB (European
`patent), GR (European patent), HU, IT (European pa-
`tent), KR, LU (European patent), MC (European pa-
`tent), NL (European patent), NO, SE (European patent).
`
`
`
`(54) Title: CHANNEL ACQUISITION METHOD AND APPARATUS FOR A COMMUNICATION SYSTEM
`
`
`
`
`
` 14
` /
`
`IKE]
`
`BSl
`
`BSZ
`
`
`COVERAGE
`COVERAGE
`
`AREA
`AREA
`
`OF BS1
`OF 852
`
`
`
`
`(57) Abstract
`
`A method and apparatus whereby a communication unit (10) transmits a communication channel request and the nearest
`base site (12) makes the communication channel grant or allocation. A base site receives the channel request signal, measures the
`received signal strength (RSSI) level of the received signal, and if that level is above a threshold level, a communication channel
`is allocated to the requesting communication unit, thus establishing a communication link. If the channel request signal does not
`have an RSSI level above the threshold, the base site delays the grant of a communication channel for a period inversely propor-
`tional to the measured RSSI level to allow other base sites the opportunity to grant a communication channel to the requesting
`communication unit. If the base site determines that another base site has granted a communication channel to the requesting
`communication unit, the allowtion process is stopped, and the base site continues scanning for channel request signals.
`
`1
`
`APPLE 1007
`
`1
`
`APPLE 1007
`
`

`

`FOR THE PURPOSES OF INFORMATION ONLY
`
`Codes used to identify Slates party to the PCT on the front pagcs of p
`applications under the PCT.
`
`amphlets publishing international
`
`United States of America
`
`l‘inland
`hunt:
`Gabon
`Unncd Kingdum
`Guincu
`(iruccu
`Hungary
`Ireland
`huly
`Japan
`Democratic Pcuplc'a chnhlit:
`of Korea!
`chuhliu of Korea
`I icclnunsluin
`Sri [Ania
`Luxembourg
`Moudcn
`Matinguscur
`
`A'l'
`
`BB
`BE
`8?
`BG
`8.]
`BR
`
`Axulrid
`Analrniiu
`Barbuda)
`Bulglunx
`Burkinu hm)
`Bulgaria
`Benin
`Brazil
`('anudu
`(‘unlral African Republic
`('ungu
`Sn IIIIZK land
`('61:: d'Ivmu:
`(‘amuruon
`(‘wchosluvnkin
`(icrmuny
`[)unmnrk
`Spain
`
`Muli
`Mongolia
`Muuritnnin
`Malawi
`Nuthcrland:
`Norway
`Pulnnd
`Romania
`Russian Fudurution
`Sudan
`Sweden
`Scncgnl
`Soviet Union
`(‘hud
`Togo
`
`2
`
`

`

`W0 92/21 21 4
`
`PCT/US92/02536
`
`10
`
`CHANNEL ACQUISITION METHOD AND APPARATUS
`
`7 FOR A COMMUNICATION SYSTEM
`
`hni
`
`I
`
`i
`
`15
`
`This invention relates generally to communication systems
`
`and more specifically to radio telephone communication systems .
`
`5.3mm
`
`Radio telephone communication systems (such as second
`
`20
`
`generation cordless telephone, or Digital European Cordless
`
`Telephone) comprise a plurality of base sites (also known as
`
`telepoints) and a plurality of radio telephones (also known as
`
`handsets). Taking second generation cordless telephone (CT2)
`
`as an example, the users of the CT2 radio telephones
`
`25
`
`communicate with users of other radio telephones or subscribers
`
`in a public switched telephone network (PSTN) via the base
`
`points. A large number of base points is desirable in certain
`
`areas (such as shopping malls) where many persons are likely to
`
`place radio telephone calls because that eliminates gaps in
`
`30
`
`coverage by the base site network. However, these base sites
`
`are not synchronized with each other. When a radio telephone
`
`user wishes to place a call, he or she causes the radio telephone
`
`unit to transmit a channel request signal. Since each base site is
`
`monitoring the channels of the CT2 system independently, the
`
`35
`
`base site that grants the channel request is not necessarily the
`
`one closest to the radio telephone unit transmitting the channel
`
`3
`
`

`

`WO 92/21214
`
`PCT/US92/02536
`
`2
`
`request signal. That may be a problem because the user may
`move out of range of the base site, thus causing the
`communication link to be dropped. On the other hand, if the
`nearest base station had made the channel grant, the radio
`telephone user would have been able to continue the
`communication while moving in a greater area. Accordingly, a
`need exists for a method and apparatus for acquiring a
`communication channel that overcomes the above problem.
`
`10
`
`15
`
`20
`
`Summary of the Invention
`Briefly, according to the invention, a method and apparatus
`are provided whereby a communication unit transmits a
`communication channel request and the nearest base site makes
`the communication channel grant. A base site receives the
`channel request signal, measures the received signal strength
`(RSS) level of the received signal, and if that level is above a first
`threshold level, a communication channel is granted to the
`requesting unit, thus establishing a communication link. Then,
`the base site maintains the communication link as long as RSSI
`level does not drop below a second threshold level that is
`substantially lower than the first threshold level.
`
`Brief Description of the Drawing§
`FIG. 1 is a simplified block diagram of a communication
`
`25
`
`system in accordance with the invention.
`FIG. 2 is a simplified block diagram of a base site in
`
`accordance with the invention.
`FIG. 3 is a flow chart of a channel acquisition method in
`
`accordance with the invention.
`FIG. 4 is a flow chart of another channel acquisition method
`
`30
`
`in accordance with the invention.
`
`Detailed Description of the Preferred Embodiment
`Referring to FIG. 1, there is shown a simplified block
`diagram of a communication system in accordance with the
`invention. A communication unit 10 (preferably, a radio
`
`35
`
`4
`
`

`

`_ W0 92/21214
`
`PCI‘/US92/02536
`
`J
`
`telephone) operates in a CT2 communication system that
`
`comprises at least first and second base sites, 12 and 14,
`respectively. The system may also comprise several other base
`
`sites. communication units, and a public switched telephone
`
`network (PSTN) 16. The communication unit 10 is closer to the
`
`first base site 12 than to the second base site 14. When the user
`
`of the communication unit 10 wishes to make a call, he or she
`
`causes the communication unit to transmit a channel request
`
`signal (which includes the unit's identification number) requesting
`
`10
`
`a communication channel. The communication unit 10 is within
`
`the coverage areas (i.e., ranges) of both the first base site 12 and
`
`the second base site 14. Thus, in a conventional CT2 system,
`
`either of the base sites could grant a communication channel to
`
`the communication device, establishing a communication link.
`
`in
`
`15
`
`the event that the second base site 14 is the first to receive the
`
`channel request signal, it would grant the channel to the
`
`communication unit 10. That would create a problem for the user
`
`of the communication unit 10 because if the user moves any
`
`further away from the second base site 14, the unit would move
`
`20
`
`out of the range of the second base site 14 and consequently the
`
`communication link would be lost. However, in accordance with
`
`the invention the first base station 12 would be the one granting
`
`the communication channel to the communication unit 10, thus
`
`solving the problem that would have been caused by a more
`
`25
`
`distant base site granting the communication channel.
`
`Referring to Figure 2, a public base site (or wireless
`
`phonebooth) 20, in accordance with the invention, is shown in
`
`block diagram form. Each of the components of the base site 20
`
`represented by a block is conventional. The base site 20, which
`
`3O
`
`is coupled to a network controller 38, comprises a radio
`
`transceiver 30, an RSSI detector 32, and a memory 36 for storing
`
`information (including the identification numbers corresponding to
`
`communication units sending channel request signals, and
`
`memory templates containing information relating to subscribers).
`
`35
`
`The RSSI detector 32 is used to determine the R881 level of
`
`signals received by the base site 20. The base site 20 also
`
`5
`
`

`

`W0 92/21214
`
`PCT/US92/02536
`
`4
`
`includes a controller 38 (e.g.. a conventional microprocessor)
`which is capable of scanning the CT2 channels to search for
`channel request signals. The controller 38 also includes'the
`capability for determining whether received signals have received
`signal levels (or strengths) at predetermined thresholds and may
`also include digital signal processing (DSP) capabilities for
`turning voice signals into digital form and processing those
`signals using well-known DSP methods. A module 40 provides
`call authentication and statistic functions for the base station 20,
`and a service command module processes requests for services
`and informs the network controller 18 what services are required.
`A PSTN interface module 34 provides an interface with the public
`
`switched telephone network 16 (shown in FlG. 1).
`The base station 20 enables a communication unit to
`
`1O
`
`15
`
`communicate with other communication units within the same or
`other communication networks, and to acquire access to any of
`
`the information and services available through the network
`
`controller. Moreover, since the base station 20 has its own
`memory, memory templates relating to a subscriber may be
`transferred to it, thus allowing the base station 20 to provide the
`requested services and/or information to the requesting
`subscriber without a continuous coupling to the network
`
`controller.
`Referring to FIG. 3, there is shown a flow chart of a channel
`acquisition method in accordance with the invention.
`ln step 100,
`a base site (e.g., base site 20) scans the CT2 channels for
`channel request signals.
`In decision 102. the base site
`determines whether a channel request signal is detected. The
`base site detects channel request signals having an RSSl level at
`or above a first threshold. The first threshold corresponds to the
`full sensitivity of the base site.
`If the base site detects a channel
`request signal in decision 102, then a further decision 104 is
`made to determine whetherthe RSSI level of the channel request
`
`signal is above a predetermined threshold level. The
`predetermined threshold level is a predetermined value of
`decibels above the maximum sensitivity level of the base site.
`
`20
`
`25
`
`3O
`
`35
`
`6
`
`

`

`W0 92/21 214
`
`PCI‘/US92/02536
`
`5
`
`That value is selected in accordance with the desired distance
`
`from the base site on which the communication channel is
`
`granted. For example, a distance of 15 meters or less from the
`
`granting base station may be desired.
`
`If the base site determines,
`
`in decision 104, that the RSSI level is at or above the second
`
`threshold, in step 106 it grants a channel to the requesting
`
`communication unit, thus establishing a commtinication link
`
`between the base site and the communication unit. The
`
`communication link is maintained as long as the signals received
`
`from the communication unit do not drop below the first threshold.
`
`The base site then continues scanning at full sensitivity.
`
`Referring to FIG. 4 there is shown a flow chart of another
`
`channel acquisition method in accordance with the invention.
`
`in
`
`step 200 the base site scans for channel request signals. A
`
`decision 202 is then made as to whether a valid channel request
`
`10
`
`15
`
`is detected (i.e., one containing the appropriate digital
`
`information). The base site continues to scan until a valid
`
`channel request signal is detected .
`
`In step 204, when the base
`
`site receives a channel request on a specific channel. it reads the
`
`20
`
`R881 of the received channel request signal. A decision 206 is
`
`then made as to whether the RSSl level measured in step 204 is
`
`below a predetermined threshold level. The predetermined
`
`threshold corresponds to the maximum distance from the base
`
`site required for establishing a communication link with that base
`
`25
`
`site.
`
`if the RSSI is not below the threshold (i.e., it is at or above
`
`the threshold), a channel is granted to the requesting
`
`communication unit (step 208).
`
`It the measured RSSI is below
`
`the threshold, a decision 210 is made as to whetherthe
`
`identification number of the requesting communication unit has
`
`30
`
`been stored. The identification number is included in the channel
`
`request signal.
`
`if the communication unit's identification number
`
`is not stored in the base site memory, the controller in the base
`
`calculates a delay time in step 212. The delay time is inversely
`
`proportional to the measured RSSl level. Thus, the higher the
`
`35
`
`RSSl level, the shoner the delay.
`
`In decision 218 it is determined
`
`whether the delay time period has expired.
`
`if it has expired, the
`
`7
`
`

`

`WO 92/21214
`
`PCI'/US92/02536
`
`(0
`
`identification number (lD) of the requesting communication unit is
`stored in the base site memory in step 222, and the channel
`allocation process returns to step 200.
`If the delay time period
`has not expired, a decision 220 is made to determine whether a
`communication channel has been granted to the requesting unit
`by another base site or by another transceiver within the same
`base site. The base site may do this by detecting the
`synchronization data (i.e., the handshake information) transmitted
`by the communication unit when a channel has been granted to it.
`In decision 210, if it is determined that the ID of the
`communication unit has been stored, then a decision 214 is made
`to determine whether a communication channel has been
`granted to the requesting communication unit by a second base
`site unit.
`If the channel was not granted, a channel grant is sent
`(224) to the communication unit.
`if decision 214 determines that
`the channel was granted, the communication unit ID is cleared
`from memory, and the channel allocation process returns to step
`200.
`‘
`Similarly, other base sites close enough to receive the
`channel request signals perform the above method. When one
`base site is closer to the requesting communication device than
`another, the closer base site has a shorter delay so that it will
`establish the communication link earlier than the more distant
`base. Once the farther base site detects the communication link
`between the communication unit and the closer base site (e.g., by
`
`detecting synchronization signals) it will not attempt to grant a
`communication channel to the communication unit. Therefore,
`the longer delay of the second base site allows the first base site
`to establish the desired communication link, and the problems
`arising from a more distant base site granting the channel request
`have been solved.
`
`What is claimed is:
`
`‘10
`
`15
`
`20
`
`25
`
`30
`
`8
`
`

`

`W0 92/21214
`
`PCT/US92/02536
`
`glaims
`
`1.
`
`In a communication system having a plurality ot base sites
`
`capable of allocating a communication channel for use by a
`
`communication unit in response to a request from the
`
`communication unit, and any of the base sites receiving the
`
`request being capable of allocating the communication channel
`
`without regard to the availability of a base site closer to the
`
`requesting communication unit, a method facilitating the use of a
`
`particular base site comprising the step of:
`
`10
`
`allocating a communication channel to the communication
`
`unit requesting the communication channel after determining that
`other base sites have not allocated the communication channel to
`
`the communication unit requesting the communication channel.
`
`9
`
`

`

`WO 92/21214
`
`PCI'/US92/02536
`
`8
`
`In a communication system having a plurality of base sites
`2.
`capable of allocating a communication channel for useby a
`communication unit in response to a request from the
`'
`communication unit, and any of the base sites receiving the
`request being capable of allocating the communication channel
`without regard to the availability of a base site closer to the
`requesting communication unit, a method facilitating the use of a
`particular base site comprising the steps of:
`(a) determining whether a communication channel is
`available for allocation to a communication unit requesting the
`
`communication channel; and
`(b) allocating the communication channel to the
`communication unit requesting the communication channel after
`determining that other base sites have not allocated the
`communication channel to the communication unit requesting the
`communication channel when it is determined that the
`
`communication channel is available.
`
`10
`
`15
`
`10
`
`10
`
`

`

`W0 92/21214
`
`7
`
`PCI'/US92/02536
`
`‘7
`
`In a communication system comprising a plurality of
`3.
`communication units and base sites, a method for allocating
`
`communication channels comprising the steps of:
`
`5
`
`with one of the communication units:
`
`(a) transmitting a channel request signal requesting a
`
`communication channel;
`
`‘
`
`with one of the base sites:
`
`(b) receiving the channel request signal, the channel
`
`10
`
`request signal having a received signal strength level;
`
`(0) measuring the received signal strength level of the
`
`channel request signal;
`
`(d) granting a communication channel to the
`
`communication unit that transmitted the channel request signal
`
`15 when the received signal level is above a first threshold to
`
`establish a communication link with the communication unit;
`
`(e) measuring the received signal level of signals received
`
`from the communication unit; and
`
`(f) maintaining the communication link as long as the
`
`20
`
`received signal level of signals received from the communication
`
`unit is above a second threshold level having a value
`
`substantially lower than the value of the first threshold level.
`
`11
`
`11
`
`

`

`WO 92/21214
`
`PCT/US92/02536
`
`I"?
`
`5
`
`10
`
`In a communication system comprising a plurality of
`4.
`communication units and base sites, a method for allocating
`communication channels comprising the steps of:
`~
`’
`
`with one of the base sites:
`
`(a) scanning for channel request signals;
`(b) detecting a channel request signal from a
`communication unit, the channel request signal having a received
`
`signal strength level;
`(0) measuring the received signal strength level of the
`channel request signal received from the communication unit;
`and
`
`(d) granting a channel to the communication unit, and
`establishing a communication link with the communication unit,
`when the received signal level is above a predetermined
`
`15
`
`threshold level.
`
`12
`
`12
`
`

`

`W0 92/21214
`
`PCT/US92/02536
`
`I!
`
`5. The method for allocallng communication channels of
`claim 4, comprising the step of:
`'
`
`(e) continuing scanning for channel request signals.
`
`13
`
`13
`
`

`

`W0 92/21214
`
`PCP/US92/02536
`
`A1
`
`in a communication system comprising a plurality of
`6.
`communication units and base sites, a method for allocating
`communication channels comprising the steps of:
`-
`'
`
`with one of the base sites:
`
`(a) scanning for channel request signals;
`(b) detecting a channel request signal having a received
`signal strength level, from a communication unit, the channel
`request signal including an identification number corresponding
`to the communication unit;
`(c) measuring the received signal strength level of the
`channel request signal;
`(d) determining whether the channel request signal has a
`received signal strength level above a predetermined threshold;
`(e) granting a communication channel to the
`communication unit, when the channel request signal has a
`received signal level above the predetermined threshold;
`(f) determining whether the identification number has been
`stored;
`(g) calculating a delay time interval when the identification
`number has not been stored;
`(h) determining whether the delay time period has expired;
`(i) storing the identification number, when the time period
`
`expires;
`(j) determining whether a communication channel has
`been allocated to the communication unit;
`(k) returning to step (a) when it is determined in step (j) that
`a communication channel has been allocated to the
`
`communication unit; and
`(l) returning to step (h) when a communication channel
`has not been allocated to the communication unit.
`
`10
`
`15
`
`20
`
`25
`
`30
`
`14
`
`14
`
`

`

`WO 92/21214
`
`PCI‘/US92/02536
`
`/3
`
`7. The method for allocating communication channels of
`claim 6, further comprising the following steps following step (t):
`
`(it) determining whether a communication channel has
`
`been allocated to the communication unit, when the identification
`
`number has been stored;
`
`(f2) allocating a communication channel'to the
`
`communication unit, when it is determined in step (it) that a
`
`communication channel has not been allocated to the
`
`10
`
`communication unit.
`
`8. The method for allocating communication channels oi
`
`claim 7, further comprising the steps of:
`
`(t3) clearing the identification number that was stored,
`
`15
`
`when it is determined in step (it) that a communication channel
`
`has been allocated to the communication unit; and
`
`(i4) returning to step (a).
`
`15
`
`15
`
`

`

`WO 92/21214
`
`PCT/US92I02536
`
`H—I
`
`9. A base site, for establishing communication links with
`_
`communication units, comprising:
`
`means for scanning for channel request signals;
`
`means for detecting a channel request signal from a
`communication unit, the channel request signal having a received
`
`signal strength level;
`means for measuring the received signal strength level of
`the channel request signal received from the communication unit;
`and
`
`1O
`
`means for granting a channel to the communication unit,
`and establishing a communication link with the communication
`unit, when the received signal level is above a predetermined
`
`threshold level.
`
`16
`
`16
`
`

`

`W0 92/21214
`
`PCI‘/US92/02536
`
`1%
`
`
`
`12\IE
`
`BS1
`
`6/14
`
`Bsz
`
`
` COVERAGE
`
`
`AREA
`OF BS1
`
`
`
`COVERAGE
`AREA
`OF 382
`
`PSTN
`
`16
`
`’//
`
`FIG. 1
`
`17
`
`17
`
`

`

`WO 92/21214
`
`7
`
`PCI‘/US92/02536
`
`am
`
`TRANSCEIVER
`
`N
`MODULE
`
`PSTN
`16
`
`
`
`
`//
`
`MEMORY
`
`
`
`
`CONTROLLER
`
`
`
`CALL
`
`SERVICE
`AUTHENTICATION
`
`COMMAND
`AND
`
`
`STATISTICS
`MODULE
`
`
`
`
` PUBLIC BASE SITE
`
`
`
`20
`
`F1012
`
`18
`
`18
`
`

`

`W0 92/21214
`
`PCl"/ US92/02536
`
`3%
`
`100
`
`105
`
`SCAN FOR CHANNEL
`REQUEST SIGNALS
`
`104
`
`RSSI AT
`PREDETERMINED
`LE¥EL
`
`
`
`102
`
`CH. REQ.
`
`DETECTED
`
`
`
`
`
`GRANT COMMUNICATION
`LINK AND CONTINUE
`OPERATION AT FULL
`SENSITIVITY
`
`FIG.3
`
`19
`
`19
`
`

`

`W0 92/21214
`
`PCI‘/US92/02536
`
`2%
`
`
`
`SCANNING FOR
`CHANNEL REQ.
`SIGNALS
`
`
`
`202
`CH. REQ. ”
`SIQNAL
` 204
`
`YES
`
`READ RSSI
`
`206
`
`ZB\\
`
`
`RSSI <
`THREEHOLD
`
`
`
`/.
`
`
`234
`
`
`
`
`YES
`
`2&6
`
`//
`CLEAR
`STORED
`
`UNIT ID.
`
`SEND CH.
`
`20
`
`20
`
`

`

`
`....ernotional application No.
`PCT/U592 '02536
`
`
`A.
`CLASSIFICATION OF SUBJECT MATTER
`
`
`
`Minimum documentation searched (classification system followed by classification symbols)
`
`U.S.
`:
`455/33.1.33.2,33.454.1.54.2,56.1;379l59,60
`
`
`
` Documentation searched other than minimum documentation to the extent that such documents are included in the fields searched
`
`INTERNATIONAL SEARCH REPORT
`
`:H040 woo/z"
`lPClS)
`US CL 1455/34.“; '
`According to lntcmational Patent Classification (IPC) or to both national classification and IPC
`
`Electronic data base consulted during the international search (name of data base and, where practicable, search terms used)
`
`
`
`
`DOCUMENTS CONSIDERED TO BE RELEVANT
`
`
`
`
`
`
`
`
`
`
`
`
`
`US, A, 4,485,486 (WEBB ET AL.) 27 November 1984, See Abstract.
`
`US, A, 4,783,780 (ALEXIS) 08 November 1988, See 001. 11, lines 27-61.
`
`
`
`US, A, 4.881.271 (YAMAUCHI ET AL.) 14 November 1989. See col. 6, lines 4-47.
`
`IUS,A,5,050,234(OHTERU)17September1991,SeeAbstract,col.2.lines20-60.
`
`
`D Further documents are listed in the continuation of Box C.
` Specilmofciwddm: dit‘ll;r‘d.lt.:icI-naatpublished-ha:thehlermtiomlfilingdnteorpriority
`
`mhmfln‘wiflnbe
`lie-donbmcitedlmmdmndth
`ammuguflmofumvmimmflud
`pmkmmmmmifmm
`e
`lobepmofpsrtiarhrnlevuee
`.
`.
`.
`l
`.
`doannenlofpuficuhrrelevnneenhechimed nsvmtionunnothe
`earherdoampublahedenoraflerthemoulfilmgdne
`consideredmdorgnnotbeeouileredlnhvolveminvmflvenep
`donmtvhichmyhmdmbumpdmiryehfls)orwhichil
`whim-mm
`citedtoembl'nhthe
`lienfimdnenfmmhereihnanorothe
`.
`Wmhwrfig)
`r
`docunntofpsmhrrelevmeenhechimedmvmrionesnnotbe
`con-Henri to involve In invasive step when the dommt is
`doclm referring to on oral iii-clown. we. exhibhion or other
`combinedvilh meormoreothernrchdoctmn. such combination
`beingohvioutospeuonskilledhthem
`mum
`
` D See patent family annex.
`
`‘X'
`
`'Y'
`
`'A'
`,
`I
`
`E
`'L'
`
`'0'
`
`'P'
`
`dmmmmwmmmmmmm -&-
`”priority/duck“
`
`dmmofhmmmfly
`
`Date of the actual completion of the intemational search
`
`
` Date of mailing of the international search report
`
`1er tit"
`16 JULY 1992
`
`
`
`Authorized officer M, Wig
`Name and mailing address of the lSA/
`
`
`
`
`W53‘ ‘‘lC-OC." J
`gflioner of Patents and Tndemrh
`5)
`
`"1&9?!Eé‘gil
`Wfshington, o.c. 20931
`EDWARD URBAN
`
`
`
`(703) 305438532}
`Facsimile No. NOT APPLICABLE
`Telephone No.
`
`
`
`
`
`Form PCT/lSA/ZIO (second sheetXJulv 1992»:
`12
`
`21
`
`