CA2155019A1

CA2155019A1 - Call completion system and method

Info

Publication number: CA2155019A1
Application number: CA002155019A
Authority: CA
Inventors: August Frederick Fath
Original assignee: Individual
Current assignee: Boeing Co
Priority date: 1993-01-29
Filing date: 1994-01-21
Publication date: 1994-08-04
Also published as: AU675108B2; AU5884994A; CN1116894A; KR960700615A; TW229344B; JPH08506702A; FI953614A; NO952978L; CN1047906C; EP0681777A1; US5479478A; WO1994017641A1; FI953614A0; NO952978D0

Abstract

A communication system enables a call from a calling party to a called party to be completed directly, irrespective of the location of the called party within a cellular telephone system. In a preferred embodiment, a calling signal is directed to a central office that creates switching information used to connect the called party to the calling party. The central office includes a switch for receiving the calling signal at a first port. The central office also includes a switch controller in communication with the switch, the switch connecting the switch controller to the calling signal. The switch controller obtains a called party identifier from the calling party. The switch controller creates a call request signal that includes the switching information and the called party identifier. The switch controller causes a switch transmitter to transmit the call request signal to the called party and when the called party responds with a call acceptance signal, at a second port, connects the second port to the first port, thereby completing the call.

Description

WO 94/17641 21~ 5 ~19 PCT/EP94/00135 Description CALL COMPLETION SYSTEM AND METHOD

Technical Field The present invention relates to telephone communications and more particularly to a pull communications method and system for accessing cellular telephones and the like.

Back~round of the Invention Both paging systems and mobile telephone systems are widely used forms of communication. These systems allow individuals to keep in contact while away from a fixed telephone.
Existing paging systems are one-way radio communication systems.
Typically, a paging system includes a centrally located control unit and a plurality of mobile pagers carried by individuals within a region. When a paging party wishes to contact an individual carrying a pager, the paging party dials the telephone number of the pager. The call is routed to the central control unit, which may be an automatic device or 20 a human-operated device (for example, a telephone answering service). The paging party can either leave a voice m~s~ge for the person being paged or key in the paging party's telephone number or other message. The central control unit will then transmit a radio signal addressed to the appropriate pager. Upon receipt of this radio signal, the receiving pager will either prompt the individual to call the central control unit to receive a message 25 or display the calling telephone number or other m~s~ge. Current paging systems are national in scope and are expected to become international in the near future.
Many prior art mobile telephone systems are cellular in nature. That is, the service area of the compa--y providing the telephone system is divided into cells or regions. A central switching office connected to each cell allows mobile telephones 30 within the cell to be contacted. Typically, an individual places a telephone call to an individual cellular phone, which is routed to the cellular central office. The central office signals the called party either directly or through a number of other cells and completes the call if the called party answers the called mobile telephone.
Many existing cellular telephone systems suffer from the problem that a 35 cellular telephone cannot receive telephone calls if it is outside its local cellular service area. This is so because none of the cell transmitters within the local network has enough WO 94117641 ~ '. PCTIEP94/00135 ~

2~5~19 range to establish communication with the cellular teiephone. Another problem is that if the cellular telephone is turned of f or tl)e user is away from the cellular telephone when a call is madc to that ~levice, tlle call will be misse(l. Another problem is that ~i1e cellular telephol1e user typically pays for incomh1g as well as outgoin~ calls. lf an unwanted call is made to the cellular telephone, the cellular telephone user must pay for it.
Several solutions have been proposed to remedy the problem of cont~cting a cellular telephone that is outside of its local cellular service area. One system ,.,~ i"s a cl~t~h~ce that stores the location of each cellular telephone. When a cellular telephone makes a call, the l~t~ba~e stores the calling telephone number and cell location of the cellular telephone in order to locate that telephone when it is called in the future.
Alternatively, each cellular telephone can be programmed to automatically send a signal to the database to update the database instead of waiting for each telephone to make an actual telephone call. Database systems of this type are undesirable because there is a relatively high overhead in creatin~ and maintaining such a ~l~t~hace. Further, the m~intPr~ ce of such ~ haces raise privacy and sccurity issues for individual cellular telephone users.
An alternative to the ~l~t~b~ce system is described in U.S. Patent No. 5,117,449 to Metroka et al. The system described therein combines a paging receiver with a cellular telephone. To contact a pager/cellular telephone outside of the local cellular service area, a calling telephone places a first call to a paging control unit, which pages the pager/cellular telephone and ~ s",iLs the telephone number of the calling telephone to the pager portion of the pager/cellular telephone. If desired, the cellular telephone user may then place a second call back to the calling telephone using the telephone number. While this system relieves some of the problems in locating distant cellular telephone users, it is undesirable because it requires a separate telephone call to be placed by the pager/cellular telephone user to connect with the calling party.

Summary of the Invention The present invention is directed to a pull comm-Jnic~tion system and components thereof for completing a call directly from a calling device to a receiving cellular telephone or comparable device. In a pr~Ç~"~d embodiment, a call is directed to a pull central office that creates switching information used to connect the receiving cellular telephone to the call placed by the calling telephone. thereby completing the original call.

3 5 In a pr~ ed embodiment illustrated herein, the pull central office includes a switch and switch controller for receiving a calling signal originating from the WO 94/17641 21~ ~ 019 PCTIEP94/00135 calling telephone at a first s~vitch port. The switch controller obtains a receiving telephone identifier from the calling party and creates a call request signal that includes the receiving telephone identifier~ identifier of a second switch port for receiving a call acceptance signal from the receiving telephone, and a message identifier for connc.,lh~g the second switch port with the first s-vitch port. The switch controller causes a switch transmitter to transmit the call request signal to the receiving telephone, and when the receiving telephone responds with a call acceptance signal at the second switch port, connects t~e second switch port to the rlrst switch port, thereby completing the call.
A receiving cellular telephone, in accordance with the p, ~l l ed embodiment described herein~ includes a receiver for receiving the call request signal from the pull central office and a pull controller that receives and decodes the call request signal. The pull controller causes a transmitter to tlahsllliL a call accel)tallce signal to the second switch port of the pull central office. Once the call acceptance signal is connectel1 the pull controller sends the message identifier to the pull central office to enable the pull central office to conne,_L the receiving telephone to the calling telephone.
In an alternate embodiment the pull controller sends the call accepLance signal only if the user indicates a desire to accept the call.

~rief Description of the Drawin~s Figure l is a block diagram of a p~ er~., ed embodiment of a pull communications system according to the present invention.
Figure 2 is a detailed block diagram of the pull communications system of Figure l.
Figure 3 is a flow diagram of the proceCcing pe~ru",led by the p,.,relled embodiment of a pull central office of the pull communication system shown in Figure l.
Figure 4 is a flow diagram of the ploce~ g pelrulllled by a pl~r~,.led embodiment of a receiving cellular telephone of the pull comm-lnic~tion system shown in Figure 1.
Figure 5 is a..flow diagram of further processing pelrull"ed by the 30 ~ fe,led embodiment of the pull central office of the pull communication system shown in Figure 1.
Figure 6 is a detailed block diagram of an alternate embodiment of the pull communications system of Figure l .
Figure 7 is a detailed bloc~; diagram of an alternate embodiment of the pull 35 communications system of Figure l.

WO 94/17641 PCT/EP94/00135 ~

S5~9 I;igurc ~ is a blocl; diagram comparin~ ~t-e operation of pull communications systen- of Figure I with a prior art system Detailed Description of the Invention An overview of the operation of pull communication system 10 according to a preferred embodiment of the present invention is illustrated in Figure 1. The pull communic~ion system includes a pull central office 12 that receives a calling signal 13 origin~tin~ from a calling telephone 14 that can be either fixed or cellular. The pull central office 12 bro~dc~ct~ a call request signal 15 to a cellular receiving telephone 16.
The receiving telephone 16 transmits a call acceptance signal 17 to the pull central office 12. A switch 18 in the pull central o~lce 12 conne~Ls the call acceptance signal 17 to the calling signal 13 to establish communication between the calling telephone 14 and the receiving telephone 16, thereby completing the original call placed by the calling party.
As shown in the more detailed illustration of Figure 2, the calling lS telephone 14 can be a fixed calling telephone 14A or a cellular calling telephone 14B.
The receiving telephone 16 includes all functional elements of conventional cellular telephones and conventional radio pagers. Since the cellular receiving telephone 16 inr~lu~es a conventional cellular telephone, it can be used as the calling telephone 14 to access another cellular receiver telephone 16. Aithough the ,~lefe"t;d embo~ nentc diccuesed herein illustrate communications between telephones, it will be obvious to those of sicill in the art that communications between other devices, such as portable computers equipped modems~ portable fax machines, etc. could be handled in the same manner.
Thus, as used herein, "telephone" includes any device for two-way voice or data communication.
As ~iccllcsed above, the pull central office 12 receives a calling signal 13 from the calling telephone 14. When the calling telephone 14 is the fixed calling telephone 14A~ it sends the calling signal to a standard central office 20 ope,aLed by a locai telephone company, such as U.S. West. When the calling telephone is the cellular calling telephone 14B, it sends the calling signal to a conventional cellular central office 22, which passes the calling signal to the standard central office 20. The standard central office passes the calling signal to the pull central office 12, regardless of whether the calling signal originated in the fixed calling telephone or the cellular calling telephone. It shouid be noted that the pull central office could include a cellular signal receiver so that the calling signal could pass directly from the cellular central office to the pull central office. At this time~ such a system is needlessly expensive for most applications because 2 ~ 9 cellular communications are much more eAycnsive than standard fixed-line communicatlons.
The switch 18 of the pull central office 12 includes a plurality of switch ports 24, one of which receives the calling signal from the standard central office 20. The 5 switch 1~ is a conventional switch such as a Private Branch Exchange (PBX) or central office switch such as an AT&T SESS or Northern Telecom DMS1000. Each of the switch ports can be internally connected to other switch ports by numerous rnini-switches 26 contained within the switch to provide selective commnnic~tion between switch ports.
The pull central office 12 includes a controller 28 in communication with 10 the switch 18 via a command line 30. The controller can be any modern workstation such as an Intel 486-based personal computer that is programmed to provide, among other things, switching cornm~ncls to the switch to selectively connect any two switch ports 24.
The controller preferably inclndPc an analog to digital (A/D) converter (not shown) to convert analog calling signals from the fixed calling telephone 14A into digital forrn for 15 use by the controller if the fixed calling telephone does not have digital capabilities.
The pull central offlce IZ includes a local tr~n~mitt~r 32 and a global tr~ncmitter 34 that are coupled to the controller 28 via respective signal lines 36, 38.
;Ihe local transmitter sends call request signals to the cellular receiving telephone 16 via one or more land-based relay towers (not shown). The global L,~ tPr sends call 20 request signals to a global network 40 that incl~ldPs one or more C~tPllitP~ that convey signals across great ~ist~nces. such as across the United States. The local and global ,dnsl,li~Lers can be those used with current nationwide paging systems.
The cellular receiving telephone 16 incll1des a local receiver 42 and a global rçceiver 44. The local receiver 42 receives the call request signals from the local 25 L~ cln;Ller 32 of the pull central office 12. The global receiver receives the call request signals from the global network 40. The local and global receivers are corinected to a computer controller 46 via rea~Jel;Live signal lines 48, 50. The controller inchlclPs a memory 52, a portion of which is non^volatile, that stores telephone idPntific~tion il,r."ll,aLion, such as a telephone identifi~ ~fion number, that allows the receiving 30 telephone 16 to verify call request signals received by the receiving tclcphone. The telephone iden~;r.~l;on h~f~""alion can additionally include an idPntific~tion of a class of users to which the user of the receiving telephone belongs. A controller interface 54 allows the controller to output to a user inforrnation or queries, such as an identification of the calling party or a query whether to accept a call, and to receive responses and other 35 control information from the user.
As is conventional. the cellular receiving telephone 16 inrludes a cellular L,ansn,iLLer 56 and cellular receiver 58 to provide normal cellular conncclions via an WO 94/17641 : PCT/EP94/00135 ~
2 ~

antenna 60. The tr~nsmitter 56 c~n establish new telephone connections as is conventional or it can transmit the call accepta.nce signal 17 to complete a call made t;om the calling telephone 14. The cellular receiving telephone 16 also includes a telephone interface 62 that provides normal telephone conversation functions. The computercontroller 46 provides a functional connection between the telephone interface and the ,transmitters and receivers to allow all conventional telephone functions.
The pull communication system 10 uses a conventional cellular central office 61 that receives the call acceptance signal 17 from the receiving telephone 16. The cellular central office 61 and the cellular central office 22 are the same entity if the receiving telephone 16 is located in the same cellular area as the cellular calling telephone 14B. Otherwise the cellular central oftîce 61 is a separate entity located outside of the cellular area of the cellular central of ~lce 2 The operation of the pull communication system 10 can best be understood in connection with the flow diagrams shown in Figures 3-5. Operation of the pull communication system 10 begins when a calling signal 13 is Lldn~ ;U~d from the fixed telephone 14A in step 64 or the cellular telephone 14B in step 66. If the calling signal is from the fixed telephone 14~ then the calling signal is tr~n~rnitted directly to the sta~ndard central office 20. If the calling signal is from the cellular telephone 14B, then the calling signal is l~i.n~,.;ned to the cellular central office 22, and then ~ ed from the cellular central office to the standard central office in step 68. In step ~0, the standard central office l.ansn.iis the calling signal to the switch 18 ofthe pull central office 12.
In step 72 the pull central office switch 18 connects the controller 28 to the h~collling calling signal 13 via the command line 30. In step 74 the controller 28 obtains ca!ling inf llllaLion needed to complete the call. The calling hlrulllld1ion inrl~ldes an identifir~tion, such as telephone number, of an individual party or a class of parties being called. Further, the calling h~ru~---aLion plcr~lably inrlud~os an id~ ;r.~ ion of the call priority. The call priority allows a caller to inform the controller whether the called party should be contacted only locally or on a "global" basis, that is, within the reach of the global network 40.
There are at least two operational modes that can be used to obtain the calling h~foll--~.lion nece:.~a-y to complete a call from the calling telephone 14 to the receiving telephone 16. In a first mode, the calling telephone llan~lllil~ a ~landal(l teîephone number that uniquely identifies the receiving telephone. For example, assume that the receiving telephone is issued a telephone number of "555-~234." Stored in the standard central office 20 is a directory that identifies the first three digits "555" of the telephone number with the pull central office 12. Stored in the pull central office controller 28 is a directo~ that decodes the number "555-1234" into a digital called party WO 94117641 21 5 ~ O 19 PCT/EW4/0~l35 identification code. As a result, the standard central office and the pull central office route the calling signal from the calling telephone to the receiving telephone simply by using the telephone number issued to the receiving party.
In a second mode, the calling telephone 14 transmits a standard telephone S number that identifies the pull central office 12 rather than the receiving telephone 16. In the second mode, the standard central office 20 stores a directory that identifies a telephone number, such as "SSS-I000," with the pull central off~ce 12. The standard central office simply acts as if the pull central office were a fixed telephone 14A. When connected to the calling signal 13, the pull central office controller 28 queries the calling 10 telephone for further infommation identifying the receiving telephone.
In a preferred embodiment implementing the second mode, each receiving telephone 16 is associated with a 64-bit identification code ( 18 digits). If the calling party knows the identification code for the desired receiving telephone, or the identification code is stored in the calling telephone 14, the calling telephone t. ans,~ s that lS identification code to the pull central office controller. Since it is p~inct~king for a user of the calling telephone to input 18 digits each time the receiving telephone is called, the calling telephone preferably is equipped with programmable speed dialing capabilities so ~hat the 18 digit code is sent automatically.
Altematively, the pull central office controller 28 stores a directory of 64-20 bit identification codes associated with information regarding the user of the receivingtelephone 16, such as the user's name. The controller 28 p~o---~L~ the user of the calling telephone 14 to input the receiving telephone user's name, such as by spe~ing or keying in the name. If more than one user has the same name the controller asks the calling telephone user to input additional i~fo~ aLion to uniquely identify the receiving tele,phone 25 user. The technology for uniquely identifying a called party via one or more queries from a computer is presently implemented in voice mail systems. The controller converts the identific~tion information into the 64-bit identification code and incorporates the identification code into the call request signal.
I.lespe~;Li~fe of the opeldLillg mode, the process for cQl~nf~ .g the 30 receiving telephone 16 to the calling telephone 14 is autorn~tiç~lly activated url,e~ er a call request signal 15 is received in the receiving telephone. Altematively, a user of the receiving telephone is given a choice of whether to accept the call request signal. In order to make such a decision, the user needs to know the identity of the calling party. In some systems, the calling party identification is obtained automatically using Automatic 35 Number Identification (ANI), a system commonly used to identify a calling party in the event the calling party enters an emergency number such as 91 1. Alternatively, the pull central office controller 28 can be programmed to obtain the identification by ploll~ ing WO 94/17641 ~ PCT/EP94/0013 the calling party to input the int`ormation alLer the controller has been connected to the calling party.
In step 76 the pull centr~l office controller 28 creates ~ message identification for the incoming call that will allow the controller to connect the call acceptance signal 17 from the receiving telephone 16 to the pull central office switch port 24 containing the incoming calling signal, to complete the call. The mPcc~e identification can also identify how to reach the calling party in the event that the incoming call signal is no longer connected to its assigned switch port 24.
In step 78 the pull central office controller 28 creates the call request signal 15. The call request signal includes: (I) the called party idçntifis~tion; (2) the calling party identification (optional); (3) an identification of the switch port or ports 24 for receiving the call acceptance signal 17; and (4) the message identification. In step 80 the controller 28 adds a message integrity check sequence based on the information in the call request signal that allows the called parly controller 82 to determine whether the call request was received without errors. Message integrity check sequences are well known in the signal processing art and can be a simple ~heckcllrn or a cyclic redundancy check (CRC).
In step 82 the pull central office controller 28 sends the call request signal 15 to either the local L,;~ er 32 or the global Ll~ ç~ 34, or both. The ~ ;C~ Pris preferably sPIected based on the call priority received from the calling telephone 14. In step 84 the ~ ",i(ler ~tt~ Ps a broadcast header to the call request signal. Thebroadcast header identifies the beginninP or end of each call request signal so that several call request signals can be broadcast in series without confusing one call request signal with the next call request signal. In step 86 the call request is broadcast locally, globally, or both.
In order to broadcast as many call request signals as possible within a limited time period, it is desirable to limit the size of each call request. In a pl~;felled embodiment, each call request signal is 256 bits in length or less. A 256-bit call request signal allows, for example, 64 bits each for the called party identific~tion and the calling party identification, 48 bits for the switch port idPntific~tion, 32 bits for the message identification, 16 bits for the message integrity check sequPnce. 17 bits for the broadcast header and 15 bits for header protection bits. The header protection bits are added to each 16-bit segment of the call request signal to ensure that the header is not ~ccidçnt~lly repeated in the call request signal.
The operation of the receiving telephone 16 is shown in Figure 4. In step 88 one of the telephone receivers 42, 44 receives the call request signal 15, depPn~in~ on whether the call re~uest signal was broadcast locally or globally. In step 90 the receiving WO 941I7641 21 S ~i O i 9 PCT/EP94tO0135 telephone receiver transmits the call re(luest signal to the telephone controller 46. In step 92 the telephone controller decodes the call request signal and compares the called party identification in the call request signal to the called party identification(s) stored in the controller memory 52 in step 94. If the idPn~ifir~tions match, then the controller 5 determines that the receiving telephone 16 is the intended recipient of the call request signal.
After determining that the cellular receiving telephone is the intended le.,ipie.lL, the telephone controller 46 initiates a call acceptance procedure. In step 96 the telephone controller causes the cellular transmitter 76 to transmit a call accepLance signal 10 17 to one of the switch ports 24 in the pull central office 12 that were desiPn~ted in the call request signal 15 as potential receivers of the call acceptance signal. The call acce~)laI ce signal is Ll~llallliLled to the pull central office via the cellular central office 61 and the standard central office 20. Once the call acceptance signal is connc~,~ed to one of the design~ted switch ports, the telephone controller sends the message identification to 15 the pull central office via the cellular ~n~ er, cellular central office and standard central office (step 98).
As mentioned above, in an alternative embodiment, the callcd party is give~n a choice of whether to accept the call from the calling party. In such anembodiment, the call request signal in~ des a calling party identifi~tion. The receiving 20 telephone controller 52 causes the controller interface 54 to output the calling party identific~tion and to ~uery the user of the receiving telephone 16 as to whether to accept the call. The user of the receiving telephone can accept the call or accept a message from the calling party. If neither the call nor a message are accepted, then the call is not answered and the receiving telephone awaits a new call. The decicion~ can be made 25 autom~tic~lly by app.op.;ate programming of the receiving telephone controller 52. For inct~nc~, the telephone controller could easily be pro~,.al..".ed to reject the call or accept â n-e~C~ge if the user does not make a decision within a predeLc.",;"ed time.
Figure S shows the operation of the pull central office 12 upon receiving the call acceptance signal 17 from the standard central office 20. In step 100 the pull 30 central office switch 18 receives the call acceptance signal at one of the ports 24 identified by the call acceptance signal. In step 102 the pull central office controller receives the message identification from the cellular receiving telephone via the switch 18.
In step 104 the controller 28 decodes the call acceptance signal to determine which calling party the call acceptance signal is responding to. In step 106 the controller 35 determines whether the calling party still is connected to the switch 18. If the calling party is still connectcd, the controller causes the switch to connect the port that received the call acceptance signal to the port that received the call from the calling party, thereby WO 94/17641 215 5 01~ PCT/EW4/OC135 ~

1() completing the call (step 108). lf llle calliny party is no longer connected, then in step 110 the controller preferably either forwards the call to a message system (not shown) or calls the original calling party in an attempt to establish a link between tl1e port that received the call acceptance signal and a port 24 selected by the controller for the original 5 calling party.
Shown in Figure 6 is an alternate embodiment of a pull communication system 10' according to the present invention. The alternate pull comm~niC~tion system 10' operates identically to the pull communication system 10 shown in Figure 2, except that the cellular central office and the pull central office are combined into a single entity.
10 All elements shown in Figure 6 that are identical to corresponding Plementc shown in Figure 2 are labeled with the same number together with a prime symbol ('). Since those elements labeled with a prime symbol are identical in structure and function to corresponding elemenls shown in Fi~sure 2 ;---d dicc~lcsed above, many of those elements are not dicc--csed again below.
A pull central ot~lce 12' of the pull comm~lni~tion system 10' shown in Figure 6 is identical to the pull central office 12 shown in Figure 2 except tha t the pull central office 12' incl~ldes a cellular receiver 112 connected to the switch 18'. The cellular rec~eiver 112 allows the pull communication system 10' to complete a call from a calling telephone 14A', 14B' to a receiving telephone 16' without usin~ a separate cellular central 20 office. Alternatively, a separate cellular central office (not shown) is used when the cellular calling telephone 14B' and the receiving telephone 16' are loeated in separate cellular areas.
When a calling signal 13' originates from the fixed calling telephone 14A', the process of completing the call continues as ~isc~lssed above with respect to Figure 2 25 until the reeeiving telephone 16' attempts to respond to a call request signal 15' with a call aceeptance signal 17'. Instead of transmitting the call aeceptanee signal to a eellular central offiee 61, the receiving telephone 16' sends the call aeeeptanee signal directly to the eellular receiver 112 in the pull eentral office 12'. The cellular receiver passes the call aeceptance signal to a switeh port 24' of the pull eentral offiee switeh 18'. The pull 30 eentral office controller 28' causes the switch port with the call acceptance signal to be connected to a switch port that received the calling signal 13' frorn the standard central office 20', thereby completing the call from the fixed calling telephone 14A' to the receivingtelephone 16'.
When the calling signal 13' originates from the celluiar calling telephone 35 14B', tl1e process of completing the call is similar to that used for completing the call from the fixed calling telephone 1 4A'. The cellular calling telephone transmits the calling signal to the cellular receiver 1 12. The cellular receiver passes the calling signal to a switch port 5 ~ 1 9 24' of the pull central o~ice switch l ~' The process of completing the cail continues as discussed above with respect to the system of Figure 2 until the receiving telephone 16' attempts to respond to a call request signal 15' with a call acceptance signal 17'. The receiving telephone 16' sends the call acceptance signal directly to the cellular receiver 5 112 in the pull central office 12'. The cellular receiver passes the call acceptance signal to a switch port 24' of the pull central office switch 18'. The pull central office controller 28' causes the switch port with the call acceptance signal to be connected to the switch port that received the calling signal 13' from the cellular calling telephone 14B', thereby completing the call from the fixed calling telephone 14A' to the receiving telephone 16'.
Shown in Figure 7 is a second alternate embodiment of a pull communication system 10" according to the present invention. The alternate pull communication system 10" operates identically to the pull communication system 10 shown in Figure 2, except that a cellular receiving telephone 114 can choose whether to send its call acceptance signal directly to a cellular central office 61" or via a low-earth orbiting (LEO) satellite 116. Further, the second alternate system 10" allows the receiving telephone 114 to receive calls intended for various users depending on which user is currently in possession of the receiving telephone. All elements shown in Figure 7 that are identical to co"t;sponding elements shown in Figure 2 are labeled with the same number together witl) a double-prime symbol ("). Since those P,l-,~.r .1~ labeled with a double-prime symbol are identical in structure and filnction to cc~ onding elements shown in Figure 2 and lisc~cced above. many of those elelnPnts are not riiccllCcerl again below.
Conventional satellites used in global comm~ni~tions, such as the s~tellites in the global network 40" are positioned 22,240 miles above the Earth so that the satellites revolve about the Earth at the same rate as the Earth rotates. That height results in each satellite always being positioned above the same point on the Earth. In contrast, LEO satellites. such as the LEO s~tPllite 116 shown in Figure 7, are positioned somewhat less than 22, 240 miles above the Earth. As a result, several LEO satellites must be launched in order to provide nationwide coverage.
In order to utilized the LEO satellite 116, the receiving telephone 114 includes a satellite ll~ c~ r 118 and a satellite receiver 120 coupled to an antPnn~ 122.
Alternatively, the satellite L-~-,a---;lLer and receiver can be coupled to the same antenna 60" that the cellular transmitter and receiver 56", 58" use. In either case. the satellite transmitter are capable of sending and receiving signals via the LEO satellite 116.
When a call request signal 15 arrives from a pull central office 12", the receiving telephone controller 46" can give a user of the receiving tclephone a choice of response modes via the controller interface 54". If the receiving telephone 114 is within Wo 94/17641 2 ~ 19 PCT/EP94/00135 range of a cellular central ot~ice 61", the user can command the controller to transmit a call acceptance signal directly to the cellular central of~lce. If out of ran~e, the user can command tl-e controller to transmit thc call acceptance signal 17 to the cellular central office 6 l via the satellite transmitter l 18 and LEO satellite l 16.
In addition to the satellite transmitter and receiver l l8, 120, the receiving telephone l 14 shown in Figure 7 includes a card reader 124 coupled to the controller 46".
The card reader is a conventional device that reads information from a small smart card (not shown3 that is similar to an ordinary credit card or ATM card. Potential users of the receiving telephone can carry the smart card that has been coded, such as by a magnetic input or a bar code. to include an identification code. The card reader reads the identification code into the controller, which stores the code in the memory 52". After the identification code is stored in the memory, the receiving telephone will recognize a call request signal 15" that includes the iderltific~tion code as its called party identification code. In addition, the fixed and mobile calling telephones 14A", 14B" can be equipped 1~ with such a card reader to read an identification code from another user's smart card and pass the identification code to the pull central office 12" as a calling party identification code. By incorporating such a card reader into the calling telephones or the receiving te~lephone, the pull communication system l0" allows numerous users to share a single phone. Further, an owner of a smart card can use any tele~)hone with a card reader to send and receive telephone calls.
As is apparent from the foregoing discussion, by co...pl~li.,e the original call from the calling party rather than requiring a separate call to be i..;~ ed by the called party, the present invention provides several advantages over the prior art. Oneadvantage is the perception by the calling party that a "normal" telephone call has been 25 made. This is in colllldsl to the delays and additional effort occurring in the requ,l~,.,.e..L
of the prior art that a new call be initi~ted from the called party to the calling party.
Another advantage of the present system is that the calling party will not be busy with another call when the called party attempts to initiate a second call.
The pull comm~mic~tion system ofthe present invention provides an ability 30 to broadcast a call request to a class of called parties. For e,~ . if a user desires to call a merh~nic and does not care which of a number of nlec~ )ics is available, in step 74 of Figure 3 the user gives the pull central office controller 28 an identirlcdtion of the mechanic class rather than an identification of a single individual being called. The receiving telephones for all users in the mechanic class include a mechanic class 35 identification in addition to a unique user identific~tion. The call request signal would then include the nlech~nic class identification and the pull central off~ce wouid broadcast a call request to all cellular telephones having a mechanic class identification. Whichever 21 5~19 mectlanic is available .m(t responds (luicl;es~ a call accept~nce si~nal is connected to the calling party to complete tlle call. Sucll a class identification allows tile calling party to connect with an available member of the class without having to separately call each member of the ciass.
S Some of the advantages of the present invention over the prior art systems may best be appreciated with an e.Yample as shown in Figure 8 Fi~ure 8 shows twocellular telepilones 126 and 128 presently located in New York, each of whose normal local cellular area is centered in Seattle. Figure 8 shows how a call from the calling telephone 126 to the receiving telephone 128 is completed using the prior art system discussed above that employs a database of the location of each user compared to a system according to the present invention. Ttle signals passed using the prior art database system are depicted as dashed lines while ttle signals passed using a preferred embodiment of the present invention are depicted as solid lines.
Using the prior art database system~ a calling signal is transmitted via a New York cellular central office 130, and a New York standard central office 132 and a long distance carrier line 134 to a standard central of~lce 136 in Seattle. The Seattle standard central of~ice sends the calling signal to a Seattle cellular central office 138 which uses its ~t~b~ce to determine tlle location of the receiving telephone 128. The Seattle cellular central office 138 sends a connecting call back to New York via the Seattle standard central office 136 and a long ~ict~nce carrier line 140 to complete the call. As a result. two long-distance telephone calls must be made and paid for in order to complete a local call in New York.
In contrast, the p,e~ll~d embodiment of the present invention completes the call fron~ the calling telephone 126 to tlle receiving telephone 128 without making any long distance calls. The calling telephone 1~6 sends a calling signal 142 to a pull central office 144 via tt-e New York cellular central office 130 and the New York standard central office 132. The pull central office~ operating according to mode 2 ~licc~-ssed above, obtains an identification of the receiving telephone 128. The pull central office broadcasts a call request signal 14G locally to the receiving tcl~phone. The receiving telephone responds by sending a call acceptance signal 148 to the pull central office via the New York cellular and standard ccntral of~lces. The pull centra! of~tce connects the calling signal 142 with the call acceptance signal 148, thereby locally completing the call from the calling telephone to the receiving telephone.
Using the prior art page and call back system, the cellular calling telephone 126 pages the receiving telephone 128 via a local office (not shown) located in New York and gives the receiving telephotle the telephone number of tl-e calling telephone. The telephone number of the calling telephone is relative to the cell from which the page was WO 94/17641 PCT/EP94/00135 ~

9 1~

made, so the calling telephone cannot leave tl-e cell if the call back is to occur. Because of the high density of cellular telephone users in New York, each cell must be relatively small, so the calling telephone cannot move very far. If the user of the receiving telephone does not call back immediately, the user of the calling telephone becomes a 5 prisoner in the cell while waiting for the call back. Further, the user of the calling telephone can make other calls only at the risk of missing the call back.
In contrast, using the pull communication system of the present invention, the calling telephone 126 calls the receiving telephone 128 locally in New York. If the user of the receiving telephone can accept the call, the connecLion is made locally. The 10 calling telephone can move freely at all times because the calling telephone remains connected to the local pull central oflice 144 during the short time it takes to be connected to the receiving telephone party.
From the foregoing it will be appreciated that, although specific embodiments of the invention have been described herein for purposes of illustration, 15 various modifications may be made without deviating from the spirit and scope of the invention. Accordingly, the invention is not limited to the embodiments described herein but is defined by the appended claims and legal equivalents thereof.

Claims

1. A pull communication system for completing a call from a calling party to a called party, comprising:
a pull central office that receives the call from the calling party, the pull central office including:
a transmitter that transmits a call request signal via a first signaling channel, the call request signal including a called party identification identifying the called party; and means for connecting the called party to the calling party in response to a call acceptance signal received from the calling party, thereby completing the call;
a receiving device that receives the call request signal from the pull central office via the first signaling channel; and a two-way communication device including:
a transmitter that transmits the call acceptance signal via a second signaling channel to the pull central office, thereby causing the pull central office connecting means to connect the called party to the calling party, thereby completing the call, and:
a receiver cooperating with the transmitter to allow two-way communication between the called party and the calling party after the pull central office completes the call, the pull communication system characterized in that:
the called party is one of plural system users each of whom is assigned a user identification code;
the receiving device includes.
means for inputting a user identification code;
a memory unit that stores the user identification code; and a processor that determines whether the stored user identification code matches the called party identification received in the call request signal; and the transmitter of the two-way communication device transmits the call acceptance signal if the user identification code stored in the receiving device matches the called party identification.

2. The pull communication system of claim 1 further characterized in that the pull central office includes means for incorporating into the call request signal a message identification identifying the call from the calling party, the transmitter of the two-way communication device transmits the message identification in the call acceptance signal,

3. The pull communication system of claim 1 wherein the pull central office transmitter includes a global transmitter that broadcasts the call request signal from the pull central office to the receiving telephone via a global network.

4. The pull communication system of claim 3 wherein the pull central office transmitter includes a local transmitter capable of broadcasting the call request signal locally to the receiving telephone.

5. The pull communication svstem of claim 1 further including a low earth orbiting satellite wherein the receiving telephone transmitter includes a satellite transmitter for sending the call acceptance signal to the pull central ofhce via a low earth orbiting satellite

6. The pull communication system of claim 1, wherein the pull central office connecting the called party to the calling party includes.
a switch that receives the call from the calling party, the switch including a plurality of switch ports, the switch associating the call with a first one of the switch ports, and a switch controller in communication with the switch ports and the pull central office transmitter, the switch controller including:
means for creating the call request signal and including switching information identifying a second switch port in the call request signal;
means for causing the pull central office transmitter to transmit the call request signal to the called party; and means for connecting the second switch port of the switch to the first switch port when the call acceptance signal is received from the calling party at the second switch port, thereby completing the call.

7. The pull communication system of claim 6 wherein the pull central office includes means for obtaining a called party identifier from the calling party and means for incorporating the called party identifier in the call request signal.

8. The pull communication system of claim 1 wherein the receiving device is connected to the two-way communication device and includes means for enabling the two-way communication device to respond to the call request signal with the call acceptance signal.

9. The pull communication system of claim 1 further characterized in that the means for inputting a user identification code includes a card reader that reads the user identification code from a card of the called party and passes the user identification code to the memory unit of the receiving device.

10. The pull communication system of claim 1 further including a standard central office connected to the pull central office by a trunk line, the standard central office receiving the call from the calling party and passing the call to the pull central office.

11. The pull communication system of claim 1 wherein the pull central office transmitter includes a global transmitter capable of transmitting the call request signal via a global network to the receiving telephone and a local transmitter capable of transmitting the call request signal locally to the receiving telephone.

12. The pull communication system of claim 11 further characterized in that the pull central office includes means for receiving a call priority designation from the calling party, the call priority designation indicating whether the calling party would like the pull central offce to signal the called party via the global transmitter, means for causing the pull central office transmitter to transmit the call request signal using the local transmitter when the designation is of a first priority, and means for causing the switch transmitter to transmit the call request signal using the global transmitter when the designation is of a second priority.

13. The pull communication system of claim 1 further characterized in that the receiving device includes means for receiving and storing an alternate user identification code, the processor determines whether either of the stored user identification codes matches the called party identification received in the call request signal, and the transmitter transmits the call acceptance signal if either stored user identification code matches the called party identification.

14 The pull communication system of claim 1 further characterized in that the pull central offce includes means for receiving from the calling party a class identifier that identifies a plurality of called parties, the receiving means passing the class identifier to a creating means for creating the call request signal and the creating means including the class identifier in the call request signal.

15. The pull communication method of claim 1, further characterized in that the pull central office that transmits the call request signal is always whichever pull central office is closest to the calling party.

16. A pull communication method of completing a call from a calling party to a called party, the called party being one of plural system users, comprising:
receiving a calling signal from the calling party at a first switch port of a pull central office which has a plurality of switch ports;
transmitting a call request signal via a first signaling channel to a paging receiver in response to receipt of the calling signal at the pull central office, the call request signal including a called party identification;
receiving the call request signal at the paging receiver;
transmitting a call acceptance signal from a telephone via a second signaling channel to a second switch port of the pull central office, receiving the call acceptance signal at the second switch port of the pull central office; and connecting the second switch port to the first switch port to complete the call, the method characterized by:
assigning each system user a user identification code;
inputting into the paging receiver the user identification code of a first one of the system users;
storing the user identification code of the first system user in the paging receiver;
comparing the called party identification received in the call request signal with the stored user identification code; and transmitting the call acceptance signal only if the called party identification matches the stored user identification code.

17. The pull communication method of claim 16, further including incorporating in the call request signal a switching identification identifying the second switch port.

18. The pull communication method of claim 16, further characterized by incorporating in the call request signal a message identification that identifies the calling signal, and incorporating the message identification in the call acceptance signal to enable the pull central office to determine which switch port to connect with the second switch port to complete the call.

19. The pull communication method of claim 16, further characterized by:
inputting into the paging receiver the user identification code of a second one of the system users;
storing the user identification code of the second system user in the paging receiver;
comparing the called party identification received in the call request signal with the stored user identification codes; and transmitting the call acceptance signal only if the called party identification matches either of the stored used identification codes.

20. The pull communication method of claim 16 wherein the transmitting a call request signal step includes transmitting the call request signal via a global network

21 The pull communication method of claim 16 wherein transmitting a call acceptance signal step includes transmitting the call acceptance signal via a cellular central office.

22. The pull communication method of claim 16, further characterized by:
receiving from the calling party a designation of call priority, wherein when the designation is of a first priority, the transmitting step includes transmitting the call request signal locally and when the designation is of a second priority, the transmitting step includes transmitting the call request signal via a global network.

23. The pull communication method of claim 16, further including determining whether the calling party has remained connected to the first port before connecting the second port to the first port.

24. The pull communication method of claim 16, further characterized by receiving from the calling party a class identifier that identifies a plurality of called parties, integrating the class identifier into the call request signal, and recognizing the class identifier at the paging receiver as being associated with the stored user identification code.

25. The pull communication method of claim 16, further including decoding the calling signal to obtain the called party identification.

26. The pull communication method of claim 16, further including querying the calling party for the called party identification.

27. The pull communication method of claim 16 the step of transmitting a call acceptance signal includes transmitting the call acceptance signal via a low earth orbiting satellite.

28. The pull communication method of claim 16, wherein the step of inputting the user identification code is further characterized by reading an identification code from a smart card.

29. The pull communication method of claim 16, further characterized by always transmitting the call request signal from whichever pull central office is closest to the calling party.