United States Patent 5,854,975
Fougnies , et al. December 29, 1998
Prepaid security cellular telecommunications system
Abstract
A cellular telecommunications system having a security feature which allows only
pre-authorized users to complete cellular telephone calls. The system and method
recognizes a cellular radiotelephone's pre-programmed and pre-selected telephone
number and an automated number identification code (ANI). The pre-selected
telephone number is reserved to the pre-paid cellular telecommunications system.
The cellular radiotelephone transmits the ANI and a dialed number identification
system code (DNIS) to a cellular switch, which contacts a host computer for call
validation by the pre-paid service provider. This system also allows
pre-authorized users to receive and pay for incoming calls as well as purchase
additional air time and monthly access fees with convenient pre-paid cards.
Inventors: Fougnies; Douglas V. (Tempe, AZ); Harned; Dan B. (Tempe, AZ)
Assignee: Freedom Wireless, Inc. (Las Vegas, NV)
Appl. No.: 559283
Filed: November 15, 1995
Current U.S. Class:455/408; 379/112; 379/114; 379/127; 379/128; 455/405;
455/406
Intern'l Class: H04Q 007/00; H04M 015/00
Field of Search: 455/408,406,409,405,407,403
379/112-114,120,121,127,128,144,130 235/380-382.5 380/23
References Cited [Referenced By]
U.S. Patent Documents
4399330Aug., 1983Kuenzel340/825.
4756020Jul., 1988Fodale379/112.
4776000Oct., 1988Parienti379/144.
4776003Oct., 1988Harris379/91.
4831647May., 1989D'Avello et al.379/91.
4845740Jul., 1989Tokuyama et al.379/91.
4852149Jul., 1989Zwick379/67.
4852155Jul., 1989Barraud379/145.
4860341Aug., 1989D'Avello et al.379/91.
4951308Aug., 1990Bishop et al.379/144.
5003585Mar., 1991Richer379/144.
5046088Sep., 1991Margulies379/211.
5127040Jun., 1992D'Avello et al.379/58.
5128938Jul., 1992Borras370/311.
5138648Aug., 1992Palomeque et al.379/219.
5138650Aug., 1992Stahl et al.379/61.
5144649Sep., 1992Zicker et al.379/91.
5220593Jun., 1993Zicker et al.379/59.
5233642Aug., 1993Renton379/59.
5265155Nov., 1993Castro379/112.
5274802Dec., 1993Altine395/600.
5291543Mar., 1994Freese et al.379/59.
5297189Mar., 1994Chabernaud379/58.
5301223Apr., 1994Amadon et al.379/58.
5301234Apr., 1994Mazziotto et al.380/23.
5309501May., 1994Kozik et al.379/58.
5321735Jun., 1994Breeden379/58.
5325418Jun., 1994McGregor et al.379/59.
5327144Jul., 1994Stilp et al.342/387.
5341414Aug., 1994Popke379/142.
5353335Oct., 1994D'Urso379/67.
5359182Oct., 1994Schilling235/380.
5359642Oct., 1994Castro379/121.
5440621Aug., 1995Castro379/112.
5465289Nov., 1995Kennedy379/59.
5517555May., 1996Amadon et al.455/408.
5517559May., 1996Hayashi et al.379/112.
5570416Oct., 1996Kroll379/144.
5592535Jan., 1997Klotz455/406.
Primary Examiner: Cumming; William
Assistant Examiner: Legree; Tracy M.
Attorney, Agent or Firm: Fish & Richardson P.C.
Parent Case Text
This is a continuation-in-part of application Ser. No. 08/364,479 filed on Dec.
23, 1994, now U.S. Pat. No. 5,722067.
Claims
I claim:
1. A cellular telecommunications system, comprising, in combination:
(a) a plurality of cellular radiotelephones each having a predetermined
subscriber telephone number;
(b) at least one local exchange carrier;
(c) at least one cellular carrier;
(d) at least one cellular switch in communication with at least one local
exchange carrier;
(e) at least one host computer in communication with said at least one cellular
switch;
(f) processing means resident in the cellular switch for receiving signals from
both the at least one local exchange carrier and the cellular carrier and
sending signals to both the at least one local exchange carrier and cellular
carrier;
(g) processing means resident in the at least one host computer for accepting
and evaluating a subscriber database comprising a plurality of records
representing subscribers to the cellular telecommunications system and including
pre-paid account balance information for each subscriber; and
(h) at least one prepaid calling card having an encrypted number which allows a
set value of air time to be added to a prepaid subscriber account balance by
entering the encrypted number into the prepaid subscriber's cellular
radiotelephone.
2. The telecommunication system of claim 1 wherein said subscriber database
further comprises activation and deactivation times for subscriber's telephone
numbers.
3. The cellular telecommunications system of claim 2 wherein the at least one
host computer communicates over a local area network.
4. The cellular telecommunications system of claim 2 wherein the at least one
host computer communicates over a wide area network.
5. The cellular telecommunications system of claim 2 wherein the subscriber
database connected to the at least one host computer is resident on a redundant
array of independent devices operably associated with and readable and writable
by the at least one host computer.
6. The cellular telecommunications system of claim 2 wherein the processing
means outputs an adjusted subscriber account balance information upon completion
of the telecommunications event with the dialed number and writes the adjusted
subscriber account balance information to the subscriber database thereby
updating the subscriber database with the adjusted subscriber account balance
information.
7. The cellular telecommunication system of claim 1 wherein the at least one
local exchange carrier communicates with the at least one cellular switch and at
least one host computer over land based telecommunication lines.
8. The telecommunication system of claim 1 wherein the at least one host
computer further includes a memory which is used to unload subscriber account
information into the memory from the subscriber database, which subscriber
account information is decremented in memory during a telecommunications event
upon connection with a dialed number.
9. A cellular telecommunications system, comprising, in combination:
(a) a plurality of cellular radiotelephones each having a predetermined
subscriber telephone number;
(b) at least one local exchange carrier;
(c) at least one cellular carrier;
(d) at least one cellular switch in communication with at least one local
exchange carrier;
(e) at least one host computer in communication with said at least one cellular
switch;
(f) processing means resident in the cellular switch for receiving signals from
both the at least one local exchange carrier and the cellular carrier and
sending signals to both the at least one local exchange carrier and cellular
carrier;
(g) processing means resident in the at least one host computer for accepting
and evaluating a subscriber database comprising a plurality of records
representing subscribers to the cellular telecommunications system and including
pre-paid account balance information for each subscriber; and
(h) a prepaid account card having an encrypted number which allows a set value
corresponding to a monthly access fee to be added to a prepaid subscriber
account balance by entering the encrypted number into the prepaid subscriber's
cellular radiotelephone.
10. A method of cellular telecommunications comprising the steps of:
establishing a prepaid subscriber account balance linked to a predetermined
cellular telephone number assigned to a subscriber;
writing the established prepaid subscriber account balance to a database;
initiating a cellular telecommunications event by calling a subscriber's
cellular telephone number;
receiving the subscriber's cellular telephone number at a cellular switch from a
local exchange carrier, the cellular switch recognizing the subscriber's
cellular telephone number as belonging to a pre-paid subscriber;
sending a first signal from the cellular switch indicating readiness to receive
digits comprising the subscriber's cellular telephone number that was called;
receiving the first signal at the local exchange carrier and sending a
multi-frequency digit string comprising at least a portion of the subscriber's
cellular telephone number to the cellular switch;
receiving the multi-frequency digit string at the cellular switch and accessing
a host computer which is in communication with the subscriber database;
validating existence of a pre-determined subscriber account balance in the
subscriber database that is not subject to any current restrictions based upon
the time of day of the telecommunications event;
establishing communications between the host computer and the cellular carrier
to obtain an available telecommunications line and out pulsing the called
subscriber's cellular telephone number only if an affirmative validation at step
(h) occurs;
checking for a connection with the subscriber's cellular telephone number and,
upon occurrence thereof, decrementing the subscriber account balance at regular
intervals during the telecommunications event until there is a disconnection
with the subscriber's cellular telephone number; and
disconnecting the telecommunications event at the host computer upon occurrence
of a negative validation at step (h) or a disconnection condition at step (j).
11. The method of cellular telecommunications in claim 10 further comprising the
step of adding a set value of air time to the subscriber's prepaid account
balance by entering an encrypted number from a prepaid calling card into a
prepaid subscriber's cellular telephone.
12. The method of cellular telecommunications in claim 10 further comprising the
step of adding a set value corresponding to a monthly access fee to the
subscriber's prepaid account balance by entering an encrypted number from a
prepaid calling card into a prepaid subscriber's cellular telephone.
Description
BACKGROUND OF THE INVENTION
The present invention relates generally to a cellular telecommunications system
having a security feature which allows only pre-authorized users to complete
cellular telephone calls. More particularly, the cellular telecommunications
system of the present invention permits cellular telecommunications providers to
obtain pre-paid subscribers and eliminate credit-risk problems. In addition, the
present invention provides anti-fraud protection for cellular service providers
by allowing subscribers to designate protection codes which must be dialed
before a telecommunications event will be completed. Further, the present
invention provides pre-paid calling cards which allow subscriber's to purchase
air-time and pay monthly access fees.
Conventional cellular telecommunications systems require the cellular provider
to undertake credit screening and certify credit-worthy subscribers before
enabling a user to access the cellular telecommunications system. Customarily, a
potential subscriber will apply to the cellular service provider, who then
undertakes a verification process to determine whether the potential subscriber
is credit-worthy. If the potential subscriber has a positive credit rating, the
subscriber is given access to the cellular system and is able to initiate or
receive unlimited cellular telecommunications events during a certain period of
time or during a certain number of billing cycles. If the subscriber regularly
pays invoices for the telecommunications services, the subscriber's access to
the telecommunications system continues unfettered. If the subscriber fails to
pay invoices as they become due, the cellular service provider has the ability
to discontinue the subscriber's access until the invoice is paid. Thus, pre-paid
telecommunications access is a desirable feature to prevent fraudulent use of
the telecommunications system. Additionally, the present invention provides
anti-fraud capabilities by requiring that a pass-code or personal identification
number (PIN) be dialed along with the called number before a telecommunications
event will be completed.
Up to now, the cellular service provider had no means available to offer
cellular telecommunications services on a prepaid basis, monitor the
subscriber's cellular telecommunications usage in real time and discontinue
access to the cellular telecommunications services immediately upon exhaustion
of a prepaid account balance. Additionally, up to now, cellular service
providers had no means available to prevent cellular theft by unscrupulous
persons retrieving equipment serial numbers from cellular signal transmissions
and "cloning" or reprogramming other cellular equipment to replicate a
subscriber's telecommunications profile.
Also, to date, cellular service providers do not have a means to allow current
pre-paid subscribers to purchase additional air time and pay for additional
monthly access fees in real time at a purchase point other than a cellular
service center in order to provide continued use of the cellular service to the
subscriber.
DESCRIPTION OF THE PRIOR ART
Land-based telecommunication systems have devised a method for allowing pre-paid
telephone usage and limiting telecommunications usage to only a period of time
equivalent to the pre-paid value. Perhaps the best example of such a land-based
telecommunications system is found in U.S. Pat. No. 5,353,335 issued Oct. 4,
1994 to D'Urso (hereinafter the "D'Urso" patent).
The D'Urso patent discloses a public switched telephone network (PSTN) which
operates on a pre-payment system and has multilingual capabilities. A telephone
user purchases a predetermined quantum of service, i.e., telecommunications time
before access and is provided a card imprinted with a unique account number. The
user is also given a series of toll free, commonly known as "1-800" numbers
which allows the user to access the prepaid telephone system. Activation of each
of the toll free numbers causes the system described in the D'Urso patent to
interact with the user in the user's native language or in a language which the
user desires to interact with the telecommunications system. Upon dialing an
appropriate toll free telephone number at a PSTN node, the user is connected
through a switching system with a host computer. The host computer prompts the
user, typically by digital voice commands, to enter the user's account number,
using the PSTN node keypad, imprinted on the user's account card. The
authenticity of the entered account number and the available amount of credit is
determined by the host computer. Account authentication and credit balance
checking is accomplished by local area network connection with a service
management computer which manages a card database containing account information
for each outstanding account card. If the account card is valid and an available
balance is verified, the host computer prompts the user to enter a speed dialing
alias or destination telephone number. The user is given a pre-set number of
attempts to enter a valid alias or destination number. The system performs
editing checks on the alias or destination number. Improper entry of a speed
dialing alias or destination for the pre-set number of attempts will cause the
host computer to disconnect the user. Upon proper entry of a speed dialing alias
or destination number, the host computer compares the available card balance
against the balance required to make a one minute phone call to the desired
destination. If the available call balance is greater than or equal to the
balance required to make that one minute call, a voice responds unit (VRU) plays
an announcement in the user's chosen language informing the user that the call
is being processed. The VRU computer uses a stored call rate associated with the
caller's destination number and the available credit balance to determine the
available call duration. A call duration timer is set in response to the
determination of the available call duration.
The VRU computer is then directed to out pulse the digits of the destination
number to a network node. When the host computer detects an off-hook condition
from the destination, the call duration timer is started and the available call
balance is depleted while the call is in progress. When the host computer
detects that the available call balance is close to depletion, the VRU computer
is bridged onto the call and plays a pending disconnect announcement in the
users chosen language. Upon exhaustion of the call balance, the VRU plays a
disconnect announcement, the call is disconnected and the host computer sends a
message to the service management computer and database that the balance on the
card is depleted.
Alternatively, if an on-hook condition at the destination occurs before the card
balance is depleted, the host computer calculates the remaining available
balance based upon the condition of the call timer and compares the computed
balance to the minimum credit threshold. The host computer then causes a VRU
computer to notify the caller, in the chosen language, whether the remaining
balance exceeds the minimum credit threshold, and the value of the available
balance and then disconnects the calling party. The host computer then sends an
update message to the service management computer and the database, notifying
them of the calculated remaining balance. The service management computer then
overwrites the present balance on the database with the calculated balance sent
by the host computer.
While the D'Urso telecommunications system allows for prepaid telecommunications
activity, it is wholly dependent upon user first calling a toll free number,
inputting account information, waiting for account validation, inputting the
called destination, waiting for destination validation and then either being
connected or not. The D'Urso system requires a plurality of input events by the
user before a call can be passed to the destination. Moreover, the D'Urso system
lacks direct interface with the remote database for real time account balance
adjustment during a telecommunications event. Rather, in the D'Urso system a
host computer queries a remote management server database to determine an
available credit balance. The host computer then looks up a telecommunications
rate for the destination number called, calculates a time value corresponding to
the credit balance for the destination number and either authorizes or rejects
the attempted call on the basis of the calculated time value. If the attempted
call is authorized, a calculated time value timer is set. Upon occurrence of an
off-hook condition at the destination called, the calculate time value timer at
the host computer is decremented until a pre-determined threshold value. As the
threshold value is reached, a voice messaging is bridged onto the call to advise
the user of the remaining calculated time value. Upon expiration of the
calculated time value, the call is disconnected. After disconnection due to
either 1) expiration of the calculated time value, or 2) an on hook condition at
the called destination, the host computer recalculates the credit balance from
the remaining time value and sends an update record to the management server and
database and overwrites the previous credit balance information stored at the
database. In this manner, the database is not actively updated as the
telecommunications activity is occurring.
Those skilled in the art will understand and appreciate that the prepaid
land-based telecommunications system described in the D'Urso patent is
fundamentally different from the cellular-based telecommunications system of the
present invention.
SUMMARY OF THE INVENTION
A need has been recognized for a cellular telecommunications system which
permits access by pre-paid users, without the need for modifying the cellular
radiotelephones commonly in use. The present invention provides a system and
method which recognizes cellular radiotelephones pre-programmed with a
pre-selected telephone number and an automated number identification code (ANI).
The pre-selected telephone number is reserved to the prepaid cellular
telecommunications system. The user merely enters the destination telephone
number and activates an off-hook condition, typically by depressing a "send"
button on the keypad of the cellular radiotelephone. The cellular radiotelephone
then transmits the ANI and a dialed number identification system code (DNIS).
Because all cellular systems operate on the basis of discrete cell sites, which
re-transmit the received signal to a central cellular service organization
cellular switch, both the ANI and the DNIS are transmitted to the cellular
switch. At the cellular switch, the ANI is recognized as one reserved to the
pre-paid cellular system and is re-directed, along with the DNIS, to the
pre-paid cellular system switch via T1 and lines or via cellular
re-transmission.
At the pre-paid cellular system switch, a host computer authenticates both the
ANI and DNIS. Upon recognition of a valid ANI, the host computer establishes
communications via either a local area network (LAN) or wide-area network (WAN)
with a remote computer database server. At the remote computer database server,
a database is maintained with pre-paid subscriber information. The pre-paid
subscriber database contains records of each pre-paid subscriber. Each
subscriber record in the database includes, at least the ANI assigned to that
pre-paid subscriber, a pre-paid account balance and a time rate for
telecommunications charges.
The host computer validates the received ANI by comparison to the ANI
information in the database. Upon validation of the received ANI, account
balance information for the account associated with the received ANI is queried
to determine if there is a positive credit balance. Upon verification that the
account has a positive credit balance, the host computer out pulses the dialed
destination telephone number to a local exchange carrier, such as one of the
Regional Bell Operating Companies.
During the call progress, the account balance information at the computer
database server is decremented based upon elapse of pre-determined time periods
at the predetermined time value for cellular telecommunications. It is important
to note the time value is deducted from the account balance at regular intervals
of time while the call is in progress.
The present invention allows a pre-paid user to access the cellular
telecommunication system and have authentication and accounting occur
transparently without any preliminary input by the user. The present invention
accomplishes this by using the ANI as the file link to identify and authenticate
the cellular telephone against the database. Thus, cellular telephone users are
freed of the need to carry and use cards, are freed of the need to enter account
information as a first step in the authentication process and the possibility of
fraud on the cellular service providers is minimized.
The present invention also allows pre-paid subscribers to accept incoming calls
from landline callers and provide a prepaid calling card procedure to
subscribers so that the system's subscribers can conveniently purchase
additional air time and pay monthly access fees. Finally, the present invention
provides a unique interface between the system cellular switch and point-of-sale
(POS) so that messages and data packets can be passed back and forth to perform
specifically desired transactions.
These and other objects, features, and advantages of the present invention will
become more apparent to those skilled in the art from the following more
detailed description of the present invention when taken with reference to the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagrammatic view of a typical cellular telecommunications system
interfaced with the cellular telecommunications system of the present invention.
FIG. 2 is a diagrammatic call flow of the prior art prepaid land-based
telecommunications system.
FIG. 3 is a call flow diagram from a typical cellular radiotelephone.
FIG. 4 is a call flow diagram at a cellular switch in accordance with the
present invention.
FIG. 5 is flow diagram illustrating call validation processing at a host
computer in accordance with the present invention.
FIG. 6 is a flow diagram illustrating call processing at the central office in
accordance with the present invention.
FIG. 7 is a flow diagram illustrating call accounting processing at a host
computer in accordance with the present invention.
FIG. 8A is a flow diagram illustrating incoming call processing in accordance
with the present invention.
FIG. 8B is a flow diagram illustrating account validation.
FIG. 9 is a flow diagram illustrating prepaid calling and processing.
FIG. 10 is a flow diagram illustrating interface processing between the system
cellular switch and the point-of-sale (POS).
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The prepaid cellular telecommunications system of the present invention is best
illustrated with reference to the accompanying drawings in which FIGS. 1 and 3
through 8B generally describe the system of the present invention and FIG. 2
depicts the prior art system described in the D'Urso patent.
With particular reference to FIG. 1, the pre-paid cellular system 10 of the
present invention is illustrated. The pre-paid cellular system, 10 interfaces
with a conventional cellular telecommunications switched network 2. Conventional
cellular telecommunications switched network 2 is a network consisting of a
plurality of cellular antennae, such as antenna 4, capable of receiving cellular
band RF signals 5, with each antenna being located in a discrete cell site such
as site 6. Each antenna is electrically linked to cellular switch 8 which
governs the operation of the cellular telecommunications switched network 2 and
links the network 2 to local exchange carrier 20 via T1 land line 12.
In accordance with the present invention, a cellular service provider 14 is
linked to the cellular telecommunications switched network 2 cellular switch 8
via T1 land lines 15. The cellular service provider 14 has a plurality of
cellular telephone numbers reserved to it for pre-paid subscribers. Each
reserved cellular telephone number has a unique automated number identifier
(ANI) associated with the reserved telephone number. These reserved cellular
telephone numbers are stored in a switch computer resident at switch 8. The
cellular service provider 14 is electrically linked to the local exchange
carrier 20 via T1 land lines 7 to communicate cellular telephone calls from the
service provider 14 to the local exchange carrier's regular network.
The service provider 14 has host computer 16 which is preferably networked
through either a local area network (LAN) or wide area network (WAN) 21 to a
remote server computer 18. In this manner a plurality of service providers may,
within a single cellular service, operate from the same remote server computer
18. The remote server computer 18 has an associated database 19 of pre-paid
subscribers, which is independently accessible by each of the service providers.
The host computer is preferably based upon a multi-processor platform such as
those made by Intel Corporation and based upon the 486 or PENTIUM
microprocessor, with each host computer having a plurality of modems and network
interface circuit boards capable of simultaneous bi-directional processing of
telecommunications data between the T1 land lines 15 and the modems and between
the host computer and the remote server. The remote server is also preferably a
multi-processor based platform capable of distributed load processing, and
fitted with a plurality of network interface circuit boards. The database is
preferably stored across a plurality of hard disk drives configured as a
redundant array of independent drives (RAID).
In the foregoing manner, a cellular transmission 5 received by an antenna 4
within a cell site 6 is received at switch 8. If the ANI and DNIS transmitted
with the cellular transmission 5 is one of the reserved pre-paid cellular
telephone numbers, the switch 8 re-directs the transmission 5 to the service
provider via the T1 and line 15. The transmission 5 is communicated to the
service providers' host computer 16, which then authenticates the ANI and DNIS
by accessing the server computer 18 and database 19. Upon valid authentication
of the ANI and DNIS, the subscriber identity is validated. The database 19 will
have records indicative of the subscriber's account balance. A check of the
subscriber's account balance in the database 19 is made to validate the presence
of a pre-paid balance sufficient to supply a pre-determined quantum of
telecommunications, e.g., one minute, at a predetermined telecommunications
charge rate associated with both the dialed number and the time of day in which
the call is placed. Upon account balance validation, the host computer 16
validates the call and passes it to the local exchange carrier 20 via the T1
land line 17.
A pre-payment telecommunications system 30 of the prior art is illustrated with
reference to FIG. 2. The system 30 requires that a pre-paid user first dial a
toll free access number at block 32. Upon connection with the toll free access
number, the user must enter an assigned account number imprinted on a card at
block 34. After the card account number is validated at block 36, a counter is
set at block 44 and a check is made at block 46 to determine whether a call on
the entered account is in progress. A negative validation at block 36 will cause
an invalid card flag to be initiated at block 38 and an appropriate voice
message from a voice response unit (VRU) announced at block 40. If an
affirmative response is not elicited from the check at block 46, the VRU prompts
the user to enter a destination telephone number at block 48. A validation check
is made at block 50 of the dialed number entered in response to the VRU prompt
at block 48. If the validation check at block 50 is affirmative, a database
associated with a management computer is called at block 54 and the account's
records are retrieved for credit balance determination. A check is made of the
credit associated with the card account to determine whether the user's account
has any available credit at block 56 and whether the available credit exceeds a
pre-determined minimum threshold at block 52. An additional check is made to
determine whether sufficient credit in the user's account balance to pay for a
threshold time value of a call, e.g., one minute, based upon a time value rate
for the destination being called is determined at block 58. If the
determinations made at blocks 52, 56 and 58 are negative for block 52 and
affirmative for blocks 56 and 68 the call is passed by out pulsing the dialed
number at block 60. If a negative determination at any of blocks 56 or 58 or an
affirmative determination at block 52 is made, an appropriate voice message is
played by the VRU at block 40 and the user is disconnected at block 42.
Upon connection with the destination number, an off-hook condition of the
destination is sensed at block 62. If an off-hook condition exists at the
destination, a timer is started at block 64 which continues until an off-hook
condition exists at the destination and the timer is stopped at block 66. Upon a
stop timer condition at block 66, the management computer is called and updated
by overwriting the user's account record with updated information based upon the
elapsed time of the call and the time value of the call at block 68. The VRU
then issues an appropriate voice message 40 to advise the user of the revised
account balance and whether the user is disconnected at block 42.
As will be understood by those skilled in the art, the foregoing description of
the pre-paid telecommunications system of the prior art 30 requires the user to
first access a toll-free n umber to be linked to a host computer, and then must
enter an account code and wait for validation and then enter a destination
number, and wait for validation before the call is passed. The present invention
operates advantageously with a cellular telecommunications system to eliminate
the need for a toll free host computer to interact directly with the user, and
eliminate the need for the pre-paid user to make multiple keypad entries.
Rather, as will be more apparent from the following description of the preferred
embodiment, the user only enters the destination number and all call processing
is handled by the host computer in conjunction with the cellular switch.
Turning now to FIGS. 3-8B, call flow in the pre-paid cellular telecommunications
system of the present invention is illustrated. It is important to note that the
cellular radiotelephones used by pre-paid subscribers are of a conventional
type, without special circuitry, modification or programming. Rather, each
cellular radiotelephone used by prepaid subscribers is programmed, in the normal
manner, with a predefined cellular telephone number reserved to the pre-paid
cellular telecommunications system 10.
FIG. 3 illustrates call initiation by a pre-paid cellular telecommunications
subscriber. The subscriber initiates a cellular call at block 72 by entering the
destination number directly at the keypad of the cellular radiotelephone. After
the subscriber enters the called number, the subscriber sends the destination
number (DNIS) by activating a send key on the keypad of the cellular
radiotelephone at block 74. The cellular radiotelephone then transmits the DNIS
and an ANI unique to the transmitting cellular radiotelephone at block 76 as
cellular signals 5 to the nearest antenna within the cell site.
FIG. 4 illustrates call processing by the cellular switch 8. The cellular switch
8 is constantly in a wait condition for receipt of cellular transmission from a
plurality of subscribers within the coverage area of the cellular switch. The
cellular switch receives the transmitted DNIS at block 78 and the transmitted
ANI at block 79. Upon recognition of the ANI as a unique ANI identifying a
subscriber in the inventive pre-paid cellular system, the cellular switch routes
the cellular call through a direct line to a host computer of the inventive
cellular system at block 80 and goes off-hook to the host computer at block 82.
The cellular switch then waits for receipt of a wink signal at block 84. Upon
receipt of a first wink signal at block 84, the cellular switch sends the ANI to
the host computer at block 88. Those skilled in the art will understand that the
sequential order of sending the DNIS and ANI may be reversed. After sending the
DNIS and ANI, the cellular switch waits for an off-hook condition from the host
computer to connect the cell. If the host computer fails to go off-hook within a
pre-determined period of time, the cellular switch drops the caller.
Call processing at the host computer is illustrated in FIG. 5. The host
computer's initiated zero state is to wait for a cellular switch off-hook
condition to the host computer. Upon receipt of an off-hook condition from the
cellular switch, the host computer send a first wink signal to the cellular
switch at block 102 which tells the cellular switch to send the DNS. The host
computer then receives the DNIS 103 from the cellular switch at block 104. After
receiving the DNIS at block 104, the host computer sends a second wink signal to
the cellular switch at block 106 which tells the cellular switch to send the
ANI. The host computer then receives the ANI 107 from the cellular switch at
block 108. The host computer accesses the subscriber database from the remote
server 11 and loads the database record corresponding to the received ANI to
memory at block 109. The received ANI is validated against the database record
in memory as one belonging to a pre-paid subscriber at block 110. Upon ANI
validation at block 110, the host computer then validates the subscriber's
pre-paid balance based upon the DNIS and time of day rate, e.g., peak or
off-peak time rates, at block 112.
Those skilled in the art will understand and appreciate that the processing of
the DNIS and ANI signals may occur in reverse order, and that different cellular
service providers may use alternative signals to represent the dialed number and
the subscriber's cellular radiotelephone. For example, the cellular
radiotelephone's electronic serial number (ESN) may be transmitted instead of
the ANI. The ANI is referenced, herein only by way of example.
Upon balance validation at block 112, the host computer goes off-hook to the
cellular provider at block 113 and a predetermined minimum time rate is
decremented from the subscriber's balance in memory at block 114 and then the
call accounting loop is initiated at block D. While at present time, it is
preferable to use memory, those skilled in the art will understand that future
improvements in LAN and WAN communication speeds and database read-write speeds
may obviate the desirability of loading the accounting processing. The host
computer then out pulses the DNIS, or another host computer-modified signal
including the called telephone number, such as a pass-code or PIN number, or the
DNIS stripped of the area code, to the local exchange carrier for connection to
obtain a central office (CO) line at block 116.
Turning now to FIG. 6, the CO is in a zero state waiting for an off-hook from
the host computer at block 118. Upon an off-hook condition from the host
computer at block 118, the CO goes off hook to the most computer and presents a
dialtone at block 120. After the T1 land line has been seized, the DNIS or a
host-computer modified DNIS, is received and routed over the T1 land line to the
number dialed out by the host computer at block 122. The CO then waits for an
off-hook condition at the called telephone number at block 124 and connects the
call.
Immediately upon occurrence of an off-hook condition at the called number, the
call accounting flow illustrated in FIG. 7 is executed. while the CO negotiates
and seizes a T1 line from the local exchange carrier, the host computer waits at
block 126 for an off-hook condition at the called number. Immediately upon
occurrence of an off-hook condition at the called number, the account balance in
memory is decremented by a predetermined value, corresponding to a minimum time
rate based upon the DNIS and the time of day rate, e.g., $0.02 for each six
seconds of telecommunications time at an off-peak, i.e., after 7:00 p.m. local
time. Thus, for example, immediately upon occurrence of an off-hook condition at
the destination number, a minimum time value of one minute is decremented from
the account balance resident in memory.
In accordance with the preferred embodiment of the present invention, the
account balance read into memory is translated to a time value based upon the
caller number (DNIS) and the time of day rate applicable. In this manner, the
account balance is converted to a time value, e.g., number of second or number
of minutes, and the time value is decremented based upon elapse of
pre-determined time periods while either the subscriber's cellular telephone or
the called number are off-hook.
After the elapse of a time period equal to the predetermined minimum time value,
the account balance is queried at block 132 to determine if there is a
sufficient account balance for an additional quantum of the minimum time value.
If a sufficient account balance is determined to exist at block 132, the process
loops back 133 and decrement the account balance by the predetermined minimum
time value at block 128. Process loop 133 continues to execute until either the
subscriber or the called number are on-hook at block 130 or until a negative
response issues to the account balance validation at block 132. If either of an
on-hook condition at the subscriber the called party at block 130 or the account
balance is not validated at block 132, a disconnection occurs, accounting ceases
and the call, including the DNIS and the elapsed time of the call are logged to
the database resident at the remote server (not shown) and the remaining account
balance is written to the database at block 134. The system then bridges to a
voice response unit and issues a voice message to the subscriber advising the
subscriber of the remaining account balance at block 136. Where it is
technically feasible to decrement the account balance directly from the
database, without loading the account balance to memory at the host computer,
those skilled in the art will understand that the step of writing the adjusted
account balance to the database may not be a necessary step.
The foregoing describes the call handling process for outgoing calls from a
cellular subscriber. In those cellular service areas where the cellular service
is offered only a "calling party pays" basis, there is no need to monitor or
control telecommunications events incoming to the subscriber. However, in those
cellular service areas where a cellular service is offered on the basis that the
subscriber pays telecommunication charges irrespective of whether the subscriber
is originating or receiving a call, the present system provides a method for
monitoring and controlling incoming cellular telephone calls to the pre-paid
subscriber and adjusting the prepaid subscriber's account balance for incoming
calls.
Inbound Landline
The security cellular telecommunication system of the present invention also has
the ability to accept incoming calls from land-line callers. In general,
separate blocks of 10,000 cellular system subscribers' phone numbers are
allocated to direct inward dialing (DID) trunks from the local exchange carrier
to the cellular system switch. These numbers are the same numbers that are
loaded into the mobile telephone service organization (MTSO) or cellular carrier
switch as the phone numbers of the system subscribers. If the land-line caller's
dialed number matches a phone number dedicated to the inventive cellular system,
the call is routed to one of the DID trunks going to the cellular switch. The
LEC switch is on a rotation so it will hunt for any available channel at the
cellular switch. The signaling on the trunks that pass calls from the LEC to the
cellular switch and the cellular switch to the MTSO is a single stage wink-start
DID protocol.
FIG. 8A illustrates a flow diagram which depicts the steps to complete the
connection of a landline incoming call with a cellular subscriber number in
accordance with the present invention. The local exchange carrier (LEC) 200
signals that there is an inbound call from a landline phone attempting to
contact a pre-paid subscriber's telephone number unique to the pre-paid cellular
telecommunications system of the present invention as shown in Step One 202. The
LEC 200 can send signals on any of the available LEC trunk channels. If the
signaling for the inbound call is valid, the cellular switch 204 sends a wink
signal back to the LEC 200 in Step Two 206 indicating that it is ready to
receive digits which relate to the land-line caller's dialed number. In Step
Three 208, the LEC 200 sends a multi-frequency digit string comprised of either
the last four, seven, or ten digits of the land-line caller's dialed number. The
number of digits sent will depend on the direct inward dialing trunk setup. The
string of digits is prefaced by a key pulse (KP) digit and flanked by a stop
(ST) digit. The land-line caller's dialed number will be a cellular system
subscriber's telephone number that the land-line caller is trying to reach. The
number of digits sent may be appended to a system configurable default area code
and/or prefix depending on the number of digits that are initially sent by the
LEC 200. If the LEC 200 fails to send all of the digits within a specified
period of time, the error is logged and the system returns to waiting for the
LEC 200 to signal that it has an incoming call.
Once the cellular switch 204 receives all of the digits, the cellular switch 204
checks for account validity 210 relating to the dialed digits. The cellular
switch 204 which enables access to the host computer for the cellular system
allows a check of whether the account is active, whether the account is subject
to restrictive dialing (e.g., restricted either by time of day that cellular
system is activated or by telephone numbers that cellular system is allowed to
connect with), and whether there is sufficient money in the account to pay for a
one minute call based on the subscriber's air-time rate table. If the account is
determined to be valid for use 212 in relation to the incoming call, the
cellular switch 204 signals the cellular carrier (CC) or mobile telephone
service organization (MTSO) 214 that there is a call coming. If the account is
not valid for use 216, the land-line caller is notified that the cellular system
subscriber is unavailable 218. The call is then logged and the system returns to
wait for the LEC to signal that it has a new incoming call. The steps involved
in checking for account validity are further detailed in FIG. 8B.
FIG. 8B shows a flow diagram for determining account validity. After the
cellular switch receives the dialed digits in block 230, the subscriber's data
record is retrieved from the host computer database in block 232. Next, the
subscriber's basic air-time rate table is extracted in block 234 from the
subscriber's data record. The rate table identifies peak and off-peak rates for
weekdays, weekends, and holidays. A real-time-clock runs on the cellular system.
The real-time-clock is used to identify the current time of day and the per
minute air-time rate for that time of day is selected in block 236.
The subscriber's remaining balance is extracted from the subscriber's data
record in block 238 and block 240 calculates whether the subscriber's account
balance holds an amount of money that is equal to the amount required for at
least a one minute call at that time of the day. If there is not an adequate
amount in the subscriber account for a one minute call, the land-line caller
receives a message in block 242 that the subscriber is unavailable. If there is
an adequate amount of money in the subscriber's account, the subscriber's
restricted access time is extracted from the subscriber's data record in block
244.
The subscriber record will contain a time-of-day that the subscriber's phone is
to be activated and a time-of-day that the subscriber's phone is to be
deactivated. The period of time falling outside of these parameters is the
subscriber's restricted access time and the time period falling within these
parameters is the subscriber's "active window". Block 245 determines whether the
current time of day falls within the subscriber's restricted access time. If the
current time of day falls within the subscriber's restricted access time, the
land-line caller receives notification in block 242 that the subscriber is
unavailable. If the current time of day falls outside of the subscriber's
restricted access time, the access payment due date is extracted from the
subscriber's data record in block 246. Block 247 determines whether the current
date is past the access payment due date. If the current date is past the
subscriber's access payment due date, the land-line caller is notified in block
242 that the subscriber is unavailable. If the current date is not past the
subscriber's access payment due date, the cellular switch signals the MTSO that
there is an incoming call in block 248.
Returning now to FIG. 8A, the next available MTSO trunk channel is used to
signal the MTSO 214 that there is an incoming call. If all of the MTSO channels
are unavailable, the land-line caller is notified by a busy signal and the
system returns to waiting for the LEC 200 to send a signal that there is an
incoming call. Once there is an available MTSO trunk channel and the cellular
switch 204 signals the MTSO 214 that there is an incoming call, the MTSO 214
winks back to the cellular switch 204 in Step Four 220 indicating that the MTSO
214 is ready to receive the dialed digits. If the MTSO 214 does not wink back in
a specified period of time, the error is logged and the system returns to
locating an available MTSO trunk channel and signaling the MTSO 214 that there
is an incoming call. In Step Five 222, the cellular switch 204 sends a
multi-frequency digit string to the MTSO 214 which comprises the cellular system
subscriber's telephone number that the land-line caller is trying to call. The
digit string is prefaced by a KP digit and flanked by a ST digit.
The inbound LEC trunk channel is then connected to the MTSO trunk channel in
Step Six 224, thereby providing an audio path for the call and allowing the
caller to hear ringing of the subscriber's telephone. If the MTSO 214 does not
detect a connection (i.e. there is either a busy signal or no answer) within a
specified period of time, the audio path between the LEC 200 and the MTSO 214 is
disconnected, the call is logged, and the system returns to waiting for the LEC
200 to signal that there is another incoming call. Alternatively, if the MTSO
214 detects a valid answer indicating that the subscriber has taken their phone
"off hook", the valid answer signal is sent to the cellular switch 204 in Step
Seven 226 so that the account balance can be debited. The subscriber account
balance is then debited per minute in accordance with previously described FIG.
7.
Prepaid Calling Cards
The security cellular telecommunication system of the present invention also
includes a prepaid calling card procedure. The purpose of the prepaid calling
card is to provide a convenient means for the cellular system subscribers to
purchase additional air-time and pay monthly access fees. Calling cards for use
with the inventive system are printed, bundled, and made widely available at
outlets such as convenience stores, grocery stores, etc. The calling cards are
sold in fixed denominations so that a subscriber can purchase a specific number
of cards in order to raise their account to a desired balance. However, the
prepaid calling cards do not allow a subscriber or user to start an account,
stop an account, or change restrictions or prompt language.
Calling cards for a specified area are printed with a unique and encrypted
number which allows them to be tracked by a point-of-sale (POS) system. The
encrypted number includes a special dialing string, the card type, possible card
value, local area code, and a form of checksum. The special dialing string is an
identifier to the system cellular switch that the incoming call is coming from a
calling card and is to be handled as such. The card type identifies whether the
card is an air-time credit or a monthly access credit. The card value provides
variable credit values. The local area code identifies where the card was
purchased so that cards purchased from the jurisdiction of one area's POS
database could not be used in another. The checksum provides a cursory way of
checking the entire number for a possible mis-dial when the subscriber calls the
number in.
The POS system holds a database of all "spent" or "used" calling cards for its
area. When a subscriber purchases a card and enters it into their telephone, the
POS checks to see that the card has not been previously used by checking the
card's number against a list of "spent" cards.
A flow diagram showing the prepaid calling card method is illustrated in FIG. 9.
A subscriber purchases one or more calling cards at block 250 from an outlet
such as a convenience store or a grocery store, as previously described above.
The prepaid calling cards are of two types, either air-time credit cards or
monthly access credit cards. After purchasing a card, the subscriber enters the
card number into the keypad of their system cellular telephone at block 252.
After entering the number, the subscriber presses the "send" key just as in
making a regular telephone call on the cellular telephone. The system cellular
switch receives the number at block 254 and uses the special dialing string to
determine that the call is to be processed as a calling card transaction.
The cellular switch then performs a cursory checksum check of the number entered
at block 256 to validate that the number was entered correctly and not
mis-dialed. If an invalid checksum results, a possible mis-dial is reported to
the subscriber at block 258 and the call is disconnected at block 260 without
incurring any charges. If a valid checksum results, the system cellular switch
reports the subscriber's current account balance to the subscriber at block 262
and the cellular switch sends the received card number and the subscriber's
telephone number to the POS system at block 264. At this point, air-time charges
begin to accrue and are incurred by the subscriber for the duration of the
transaction.
The card number is validated at block 266 where the card number entered is
compared with a list of card numbers that have already been "used" or "spent".
If the card number entered is found on the "used" list, the subscriber is
informed of the card's "spent" status at block 268 and the call is disconnected
at block 260. The validation step at block 266 also instructs the POS to check
that the card being entered is a card that is valid for the specific POS system
by comparing the local area code field of the card number with the POS area code
identifier. If the area code relating to the calling card is found to be invalid
for the area covered by the POS, the invalid area is reported to the subscriber
at block 268 and the call is disconnected at block 260.
If the card number is determined to be valid at block 266, the subscriber's
account is credited at block 272 according to the card type and value. The new
credit balance is then reported to the subscriber at block 274 and the call is
disconnected at block 260.
When a prepaid access fee credit card is entered into the system, the access fee
is covered for another month and the access fee due date is updated accordingly.
Multiple access fee due dates being entered during any one given month will
result in the access fee due date moving farther and farther out in time. The
entire procedure outlined in FIG. 9 must be repeated for each individual calling
card.
Interface Between System Cellular Switch and Point-of-Sale (POS)
The system cellular switch is connected to the Point-of-Sale system via an
Ethernet link. Messages and data packets are passed back and forth to perform
desired transactions. FIG. 10 illustrates the possible types of transactions
between the system cellular switch 300 and the POS 302.
A number of transactions are carried out by sending or transferring information
from the cellular switch 300 to the POS 302. For example, the call activity
logging function in block 304 involves passing information about a specific call
that was recently terminated from the cellular switch 300 to the POS 302 for
insertion into the database. The information is then archived in the system and
can be used to provide a detailed report on call activity. Further, the calling
card validation and account crediting function in block 306 transfers the
subscriber's telephone number and the calling card number they entered into
their cellular telephone from the cellular switch 300 to the POS 302 for card
validation and subsequent account crediting.
Also, the cellular switch 300 in block 308 confirms to the POS 302 that
requested updates to a subscriber's data record have been successfully executed.
Finally, the switch error annunciation function in block 310 sends information
about a switch error from the cellular switch 300 to the POS 302 so that those
viewing a terminal are alerted that there is a problem.
There are also s number of transactions that are carried out by sending or
transferring information from the POS 302 to the cellular switch 300. For
example, the call activity logging acknowledgment function in block 312 confirms
to the cellular switch 300 that the received activity record has been
successfully archived into the POS database. Also, the calling card validation
response function in block 314 informs the cellular switch 300 that the received
calling card number for a specified subscriber is either valid or invalid.
Further, acknowledgment for receiving an error message from the cellular switch
is sent from the POS 302 to the cellular switch 300 in block 316 to indicate
that the error message has been successfully archived and that the proper
notification has taken place. Finally, the subscriber update function in block
318 sends the modified subscriber data record which has been updated at the POS
302 from the POS 302 to the cellular switch 300 where it replaces the current
record information for that subscriber.
Thus, in the present invention, the disadvantages of the prior art are overcome,
particularly as those disadvantages would affect a cellular user. By eliminating
the need for the user to make unnecessary dialing entries and limit the user's
dialing entry only to the destination number the present invention represents a
valuable and needed advance in the art. Additionally, by using the ANI to
identify the subscriber, rather than the situs of the call, the present
invention provides for transparent call processing for the end-user and achieves
a fraud tolerance level not presently available to service providers.
Further, the present invention allows for prepaid cellular subscribers to accept
incoming calls even when their cellular service requires payment for incoming
calls. Also, the present invention includes a prepaid calling card means which
allows subscribers to conveniently purchase and add additional air time as well
as pay for monthly access fees. Finally, the present invention provides for a
unique interface between the system cellular switch and the pint-of-sale (POS)
which enables specifically desired transactions to take place such as: providing
particular reports, validating cards and crediting accounts, validating account
updates, and identifying problems within the system.
While the invention has been described with reference to its preferred
embodiments, those skilled in the art will understand and appreciate from the
foregoing that variations in equipment, operating conditions and configuration
may be made and still fall within the spirit and scope of the present invention
which is to be limited only by the claims appended hereto.
* * * * *
