MXPA99010399A - Processing of emergency calls in wireless communications system with fraud protection - Google Patents

Abstract

A call processing system for a wireless communications network comprises means (30, 52) for detecting a call placed from a mobile station in the network to a multi-digit number dialed by a user of the mobile station;means (32-34, 60-62) for determining whether the call is indicated to be fraudulent;means (36-38, 54-56) for determining whether the dialed number is a predefined multi-digit emergency number;means (40, 66) for completing the call if the call is indicated not to be fraudulent, or if the dialed number is determined to be an emergency number even if the call is indicated to be fraudulent;and means (42, 68) for blocking the call if the call is indicated to be fraudulent and the dialed number is determined not to be an emergency number.

Description

PROCESSING EMERGENCY CALLS IN A WIRELESS PROTECTIVE WIRELESS COMMUNICATIONS SYSTEM BACKGROUND OF THE INVENTION Technical Field The present invention relates to the processing of emergency calls in a wireless communication system that implements fraud detection and management procedures and, more specifically to prevent such calls from being blocked due to the implementation of procedures of this type. Related Prior Art The prior art includes cellular radio systems that have been operating in the United States of America and in Europe for the last two decades. A cell phone service operates much like a wired telephone service, fixed in homes and offices, except that radio frequencies are used instead of telephone wires to connect telephone calls between mobile subscribers. Each mobile subscriber receives a private directory phone number (10 digits) and the service is usually charged on the basis of the amount of "airtime" it uses when communicating via cell phone, monthly. Many of the service features available to landline phone users (for example, call waiting, call transfer, tripartite calls, etc.) are also usually available to mobile phone subscribers. In each market area, mobile subscribers are usually free to subscribe to services from at least two systems. The local system from which a service is subscribed is known as the "domicile" system. When moving outside the domicile system, a mobile subscriber can obtain the service in a distant system if there is a "move" agreement between the domiciliary system operators and the "visited" systems. The architecture for a typical cellular radio system is presented in Figure 1. A geographic area (eg, a metropolitan area) is divided into several contiguous, smaller radio coverage areas, which are referred to as "cells" as, for example, C1-C10 cells. The C1-C10 cells are serviced by a corresponding group of fixed radio stations, which are known as "base stations", B1-B10, each of which includes a plurality of radio frequency (RF) channel units (transceivers) operating in a subset of RF channels assigned to the system, as is known in the art. The RF channels assigned to a given cell can be reassigned to a distant cell in accordance with a frequency reuse plan, as is well known in the art. In each cell, at least one RF channel, known as "control" channel or "paging / access" channel, is used to carry supervision or control messages. The other RF channels are used to carry voice conversations and are therefore known as "voice" or "phonic" channels. Mobile phone users (mobile subscribers) in C1-C10 cells are equipped with portable (hand-held), transportable (hand-carried) or mobile (vehicle-mounted) telephone units, collectively known as "mobile stations", as for example the mobile stations M1-M5, each of them is in communication with a nearby base station. Each of the mobile stations M1-M5 includes a controller (microprocessor) and a transceiver, as is known in the art. The transceiver in each mobile station can tune to any of the RF channels specified in the system (while each of the transceivers in the base stations B1-B10 usually operates only in one of the different RF channels used in the corresponding cell With reference still to figure 1, the base stations B1-B10 are "connected and controlled by a mobile telephone switching office (MTSO) 20. The MTSO 20, in turn, is connected to a central office (not specifically illustrated in Figure 1) in a public switched telephone network (PSTN) 22 of landline (wired), or to a similar facility such as a digital network of integrated services (ISDN). The MSTO 20 transfers calls between subscribers of wireline and mobile subscribers, controls signaling to mobile stations M1-M5, compiles statistics for billing, stores subscriber service profiles, and provides operation, maintenance and testing of the system. An important function of the MTSO 20 is to carry out a "transfer" of a call from one base station to another base station B1-B10 as one of the mobile stations M1-M5 moves between the cells. The MTSO 20 monitors the quality of the voice channel in the old cell and the availability of voice channels in the new cell. When the quality of which falls below a predetermined level (for example, the user moves out of the old base station towards the perimeter of the old cell), the MTSO 20 selects a voice channel available in the new cell - and then instructs the old base station to send to the mobile station on the current voice channel in the old cell a transfer message informing the mobile station to tune to the selected voice channel in the new cell. Access to the cellular system of Figure 1 by any of the mobile stations M1-M5 is controlled based on the mobile identification number (MIN) and an electronic serial number (ESN) that are stored in the mobile station. The MIN identifies the service subscription and is a binary representation of the mobile subscriber's 10-digit directory phone number. The MIN is assigned by the cellular service provider (home system operator) and is usually programmed in a mobile station either when it is acquired by the original user or when it is sold to another user (ie, at the time of the installation of the service). The valid subscriber MINs (which pay) are stored by the MTSO 20. The ESN uniquely identifies the mobile station and is a digital number that is supplied by the manufacturer and permanently stored in the mobile station (ie, factory-set) , so as not to be disturbed in the field). The ESNs of mobile stations that have been reported as rogado can be marked appropriately by the MTSO 20 and deny them the service permanently. A user authorization for cellular service is usually performed at each system access (eg, call origin) by a mobile station. When an access is carried out, the mobile station sends the MIN and ESN to the system. The MTSO 20 maintains a "white list" that contains the MIN / ESN pairs of valid address subscribers and a "black list" that contains the ESNs of stolen or otherwise unauthorized mobile stations. The MPSO 20 checks the received MIN / ESN pair in order to determine if it belongs to a valid subscriber of address, and, if not, if the MIN belongs to an authorized "subscriber in transit" from another system and if the ESN has been placed on the blacklist. If the MIN / ESN pair is not valid, either if the MIN is not recognized or if the ESN is on a blacklist, the mobile station may deny access. Otherwise, it is considered that the user is valid and access is accepted. The original cellular radio systems, in accordance with what is generally described above, used analog transmission methods, specifically frequency modulation (FM) and duplex RF channels (two directions) in accordance with the Advanced Mobile Phone Service standard.

(AMPS) (advanced mobile telephony service). The original architecture of AMPS (analog) formed the basis of an industry standard sponsored by Electronics Industries Association (EIA) (Association of Electronic Industries), and the Telecommunications Industry Association (TIA) (Association of Telecommunications Industry), and is known as EIA / TIA-553. Towards the mid-1980s and until the late 1980s, however, the cellular industry in both the United States of America and Europe began to move from an analog technology to a digital technology, motivated in large part by the need to solve the rapid growth in terms of the subscriber population and the growing demand for system capacity. The industry thus developed several air interface standards that employ digital voice coding techniques (analogue to digital data conversion and voice compression) and advanced digital radio techniques, such as time division multiple access (TDMA) or Multiple access by code division (CDMA), to multiply the number of voice circuits (conversations) per RF channel (that is, to increase capacity). In Europe, the GSM standard, which employs TDMA with "frequency hopping" has been widely implemented. In the United States of America, the EIA / TIA has developed several digital standards including IS-54 (TDMA) and IS-95 (CDMA), both are "double-mode" standards insofar as they support the use of digital channels. original AMPS analog voice and control in addition to digital voice channels defined within the existing AMPS framework (in order to facilitate the transition from analog to digital data and to allow continuous use of existing analog mobile stations). The double-mode IS-54 standard, in particular, has become known as the digital AMPS standard (D-AMPS) More recently, the EIA / TIA developed a new specification for D-AMPS, which includes a suitable digital control channel to support data services and an extended mobile station battery life. This new specification, which is based on the IS-54B standard (the current revision of IS-54), is known as IS-136. In addition to providing a new digital radio transmission format, many of the newest digital standards (including IS-156 and IS-95) specify the use of an authentication procedure to confirm the identity of mobile stations that require service in a cellular system. This procedure, which has also been imported into more recent analog standards, such as "IS-91 AMPS narrow-band pair (N-AMPS) and revision A of EIA / TIA-553 (EIA / TIA-533A currently in process) of development), was developed in response to the widespread fraudulent use of MIN / ESN pairs to steal cellular service from existing analog systems Many of the mobile stations that have been sold to date do not meet the requirement to be proof of manipulation by unauthorized persons for ESN, and, therefore, can be easily programmed with an ESN (there is no requirement to be tamper proof by persons not authorized for MIN and, therefore all mobile sections can be easily programmed Thus, these mobile stations can be programmed to transmit any MIN / ESN pair in order to "trick" the system into granting access. Additional information about this "imbalance" of MIN / ESN and the resulting loss of revenue and service can be found in the article entitled "Cellular Fraud" by Henry M. Kowalczyk, in Cellular Business, dated March 1991, in pages 32-35. Fraud in the form of mismatch of MIN / ESN arises primarily in a "manual displacement" environment where cellular systems are not interconnected on a real-time basis. Since each MTO usually contained only a list of valid MIN / ESN pairs that belonged to home subscribers, did not have immediate access to the corresponding lists in the other systems. Accordingly, by using a MIN of a scrolling subscriber (ie, a 10-digit directory telephone number that contains an area code other than the local area code of the home address operator) and an ESN Not belonging to a blacklist, a fraudulent mobile station could receive service from the local cellular system until the reception of an indication of validity of the MIN / ESN pair (perhaps hours later) of the residence system of the subscriber in transit (or a clearing house). In an "automatic scrolling" environment, however, cellular systems are interconnected with each other based on real time in accordance with the provisions of an industry standard such as, for example, IS-41 EIA / TIA (or through its own signaling protocol). Accordingly, the serving cellular system can obtain a MIN / EFN pair verification from the address system virtually immediately and can therefore deny service to a person wishing to cheat MIN / ESN without significant delay. Of most concern recently has been a type of fraud known as "cloning" where a fraudulent user adopts the MIN / ESN bona fide pair of a valid (paying) subscriber. The fraudulent user can surreptitiously acquire a MIN / ESN bona fide pair, or even a list of valid MIN / ESN pairs, in several ways. For example, in some cases, MIN / ESN bona fide numbers are printed and can be read from a label that is fixed to a mobile station belonging to a valid subscriber. In other cases, a list of MIN / ESN bona fide pairs can be purchased on the "black market" or directly from an employee of the cellular operator. In addition, since each mobile station transmits the MIN / ESN pair to the service exchange at each system access, one or more pairs of MIN / ESN bona fide can be intercepted by listening to the radio transmissions on the control channel (analog) . The cellular industry has developed several provisional solutions to detect fraud. For example, current cellular systems track suspicious activities that indicate cloning-type fraud, such as when a particular MIN / ESN is shown simultaneously participating in two flames, or, alternatively, has made two calls from two different locations within a shorter time interval than normally required to travel between these locations. However, the long-term solution to the problem of fraud seems to be found in the prevention of fraud rather than in the simple detection of fraud. Authentication procedures in the latest industry standards focus on fraud prevention by requiring mobile stations to have the appropriate authentication data (in addition to an appropriate MIN / ESN) in order to receive system service. The authentication data is generated from identical sets of shared secret data (SSD) that are periodically stored and updated in a mobile station and its service system. The authentication data generated in the mobile station is sent to the service system to be compared with the authentication data generated internally for the purpose of confirming the identity of the mobile station.

Since a cloned mobile station does not have access to the initial value of the SSDs or to the subsequent history of SSD updates in a valid mobile station, the authentication data sent by the cloned mobile station will not correspond to the authentication data in the system, and therefore the system will be able to recognize the cloned mobile station and deny it the service. In the authentication process, the base station generates and sends to the mobile station a random bit pattern, which is known as RAND or RANDU, in the analog control channel (ACCH), digital control channel (DCCH), analog voice channel (AVCH) or digital traffic channel (DTCH). Each of the mobile stations and base stations uses RAND or RANDU, a portion of SSD called SSD-A (the remaining portion SSD-B, is used for encryption, and not for authentication), along with other parameters ( for example the MIN and ESN of the mobile station) as inputs to a Cellular Authentication and VOICE Coding (CAVE) algorithm, which is defined in appendix A of each of IS-54 and IS-136, to generate a response of authentication called AUTHR or AUTHU (depending on whether RAND or RANDU is used, respectively). The authentication response calculated in the mobile station is sent to the base station to be compared with the authentication response calculated in the base station. If the authentication responses correspond, the authentication is considered to be successful (ie, the base station and the mobile station are considered to have identical sets of SSDs). However, if the comparison in the base station fails, the base station may deny the service to the mobile station or start the SSD update process. The procedure for updating SSD for another mobile station includes the generation of a new SSD value through the initialized KB application with mobile station specific information (ESN), certain random data (RANDSSD), and a secret, permanent authentication key (key A), assigned uniquely to the mobile station. While the original MIN / ESN screening procedures and the most recent authentication procedures are useful in dealing effectively with the fraud problem, these procedures also cause certain complications in practice. Specifically, these procedures may result in the blocking of an emergency call made through a mobile station mistakenly suspected of fraud. As is known in the art, a lack of correspondence MIN / ESN or AUTHR / AUTHU in the system can be caused, for example, by a formatting or transmission error in the mobile station. In this case, a valid subscriber who makes an emergency call may be denied service when it is most urgently required. Furthermore, even if the lack of correspondence MIN / ESN or AUTHR / AUTHU truly reflects the existence of a cloned mobile station, it may nevertheless be desirable to allow the emergency call in order to protect the health or well-being of the user of the cloned mobile station. The risk of blocking an emergency call is somewhat reduced in some systems such as those that implement the IS-136 standard. In these subtopics, a mobile subscriber can initiate an emergency call by pressing an emergency call button on the mobile station which, in turn, activates an emergency call dialer in the call originating message from the mobile station towards the system. Upon receiving this message, the system will ignore the number field of the calling party in the message, either it will not apply fraud detection procedures for this call or it will still process the call even if an indication of fraud is detected with the object of routing the emergency call to the appropriate emergency center. Nevertheless, in these systems there are no provisions to avoid blocking an emergency call made by dialing an emergency number (for example, "911") if the call fails in one or several of the revisions used by the various procedures of fraud detection and / or fraud prevention. COMPENDIUM OF THE INVENTION Taking into account the shortcomings of the prior art approach to the processing of calls while also applying fraud protection, the present invention offers new techniques for processing calls in such a way that any emergency call is carried out at despite the use of fraud protection. In one aspect, the present invention provides a first method for processing calls in a wireless communication system. The first method comprises the steps of detecting a call made from a mobile station in the system to a multi-digit number dialed by a user of the mobile station; determine if the call is indicated as fraudulent; if the call is indicated as fraudulent, determine whether the dialed number is a predefined multi-digit emergency number; if the call is indicated as non-fraudulent or if the dialed number is determined as an emergency number, carry out the call; and if the call is indicated as fraudulent and the dialed number is indicated as a non-emergency number, invoke a predetermined fraud handling procedure selected by a system operator. In another aspect, the present invention offers a second method for processing calls in a wireless communication system. This second method comprises the steps of detecting a call made from a mobile station in the system to a multi-digit number dialed by a user of the mobile station; determine whether the dialed number is a predefined multi-digit emergency number; if the dialed number is determined as an emergency number, make the call; if the dialed number is determined as not being an emergency number, determine if the call is considered fraudulent; if the call is indicated as non-fraudulent, carry out the call; If the call is indicated as fraudulent, invoke a predetermined fraud handling procedure selected by a system operator. In the first method or in the second method of the present invention in accordance with the above, the step of determining whether the dialed number is an emergency number may comprise the step of comparing the digits of the number dialed with the digits of the number of emergency. For example, if the emergency number is "911," the check step may include the sub-steps of determining whether the first digit of the dialed number is 9; and if the first digit of the dialed number is "9", determine if each of the second digit and the third digit of the dialed number is "1". In addition, in any method, the selected fraud handling procedure may comprise blocking the call.

In another aspect, the present invention offers a call processing system for a wireless communication network. The call processing system comprises means for detecting a call made from a mobile station in the network to a multi-digit number dialed by a user of the mobile station; a means to determine if the call is considered fraudulent; means for determining whether the dialed number is a predefined multi-digit emergency number; means to carry out the call if the call is considered as not fraudulent, or if the dialed number is determined as an emergency number even if the call is considered fraudulent; and a means to block the call if the call is indicated as fraudulent and the dialed number is not an emergency number. For applications in which the mobile station is identified by a mobile identification number (MIN) and an electronic serial number (ESN), the means of determining whether the call is fraudulent may comprise a means to determine whether the MIN / ESN pair it is valid or it is indicated that you are making another call. In addition, for applications in which each of the network and the mobile station generates an authentication response, with the authentication response generated in the mobile station sent to the network, the means to determine whether the call is indicated as fraudulent may be comprising a means for determining whether the authentication response sent from the mobile station corresponds to the authentication response generated in the network. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be better understood and its various objects and advantages will be apparent to those skilled in the art with reference to the following drawings in which: Figure 1 is a block diagram of a radio communications system copy; Figure 2 is a flow diagram illustrating the steps for processing calls in the system of Figure 1, in accordance with a first embodiment of the present invention; and Figure 3 is a flow chart illustrating the steps for processing calls in the system of Figure 1, in accordance with a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION _ Referring now to Figure 2, there is shown a flow diagram of the steps executed by the system (for example, the MTSO 20 in Figure 1) in accordance with a first embodiment of the present invention. In step 30, the system determines whether a new call from a mobile subscriber has been detected. For purposes of illustrating the present invention, it is considered that any call detected by the system in step 30 represents a multi-digit number that has been dialed by the mobile subscriber (ie, the dialed number is sometimes referred to herein as the " number B "). However, it will be understood that the system can also support the function of the prior art which allows the placement of an emergency call or of another type by pushing a corresponding corresponding button in the mobile station. With reference to Figure 2, if a new call is detected in step 20, the system proceeds to step 32 and reviews the call to determine if the fraudulent one. Revisions employed in known fraud detection and / or prevention procedures, including those previously discussed, can be applied in step 32. In step 34, the system determines whether or not fraud has been detected from one or several of the revisions applied in step 32. If there is no indication of fraud, the system skips to step 40 and carries out the call. On the other hand, if fraud is indicated, the system proceeds from step 34 to steps 36-38 and carries out an abbreviated ("mini") analysis of number b in order to determine whether the called number is an emergency number (that is, if this call is an emergency call). In the preferred mode, the mini-analysis of number B tries to quickly and efficiently check the digits of the number dialed with the emergency number (s) defined for the service area of the system. In the United States of America, for example, the series of digits "911", "0911" and / or "1911" can be used to make emergency calls. Thus, if the system is operating in the United States of America, the system can begin the mini-analysis of number B by determining whether the first digit of the dialed number is "9", "0", or "1". If the first digit is "9", the system can then determine if the second and third digits are both "1". Similarly, if the first digit is found to be "0" or "1", the system can then determine whether the second digit is "9" and, if the second digit is "9", if the third digit and the fourth digit are both "1". Returning to figure 2, based on the results of the mini-analysis of number B, the system can determine, in step 38, whether the dialed number is an emergency number, or, alternatively, a non-emergency number. . If the dialed number is an emergency number, the system will carry out the call in step 40. On the other hand, if the call is not an emergency call, the system will proceed to step 42 and invoke the procedures for handling the emergency call. fraud (that is, against fraud measures) selected by the system operator. Thus, for example, in step 42, the system can deny (block) the call, route the call to a human being or carry out an SSD update. Referring now to Figure 3, a flow chart of the steps executed by the system in accordance with a second embodiment of the present invention is illustrated. The mode illustrated in Figure 3 employs an emergency call dialer that is set (ie, is set to the value "1") if a call processed by the system is determined as an emergency call. Before each new call, the system resets the emergency call dialer (ie, the "0" value) in step 50. In step 52, the system determines whether a new call has been detected. If a new call has been detected, the system proceeds to steps 54-56 and uses the mini B-number analysis to determine if the call is an emergency call, similar to steps 36-38 in the Figure 2. If the call is found to be an emergency call, the emergency call dialer will be set in step 58 and the call will be reviewed to determine the existence of a fraud in step 60. On the other hand, if the call is not an emergency call, the system goes directly to step 60 without setting the emergency call dialer. After the application of the fraud reviews in step 60, the system determines whether a fraud is indicated in step 62. If a fraud is indicated, the system then determines in step 64, whether the emergency call dialer has been established, indicating that the call in progress is an emergency call. If -the emergency call dialer has been set, the system will make the call in step 66. The system will also make the call if no fraud was detected in step 62 regardless of whether or not the call in progress is a call of emergency. On the other hand, if a fraud was detected in step 62 and if the call was found not to be an emergency call in step 64, the system will invoke the appropriate fraud handling procedures in step 68. It will be noted that, in the modality illustrated in figure 2, the system initially determines if the call is indicated as fraudulent, and, if so, if it is an emergency call. In contrast, in the embodiment illustrated in Figure 3, the system initially determines whether the call is an emergency call, and, if so, whether said call is indicated as fraudulent. In both modalitiesHowever, if the call is an emergency call, it will not be blocked despite not passing fraud reviews applied to the system. People with certain knowledge in the art will note that the mini-analysis of number B of the present invention may have to be performed less frequently in the embodiment of figure 2 compared to the embodiment of the figure. 3, since it is expected that the vast majority of calls will normally pass fraud reviews in such a way that only a relatively small number of calls will be submitted to the mini-analysis of number B in Figure 2, while the analysis of number B will be will apply to all calls in Figure 3. While some forms or embodiments of the present invention have been illustrated above, those skilled in the art will readily recognize that many modifications and variations may be made with respect to the forms and embodiments of the present invention presented. here ~ without substantially departing from the spirit and scope of the present invention. Thus, for example, the modality illustrated in Figure 3 can be modified in such a way that once determined in step 56 that the dialed number is an emergency number, the system will go to step 66 and make the call without making any revision to determine if it is a fraud. If such a modification were made, it would be possible to eliminate steps 50, 58 and 64, and replace the branch from step 56 to step 58 with a branch from step 56 to step 66, and the branch from step 62 to step 64 with a branch from step 62 to step 68 in figure 3.

Accordingly, the form of the present invention presented herein is exemplary and is not intended to limit the scope of the invention in accordance with that defined in the following claims.

Claims (25)

1. CLAIMS 1. A method for processing calls in a wireless communication system, the method comprising the steps of: detecting a call made from a mobile station in said system to a multi-digit number dialed by a user of said mobile station; determine if said call is indicated as fraudulent; if said call is indicated as fraudulent, determine whether said dialed number is a predefined multi-digit emergency number; if said call is not indicated as fraudulent, or if said dialed number is determined as an emergency number, carry out said call; and if said call is indicated as fraudulent and if said dialed number is not determined as an emergency number, invoke a predetermined fraud management procedure selected by an operator of said system. The method of claim 1, wherein said step of determining whether said dialed number is an emergency number comprises the step of collating the digits of the dialed number with the digits of said emergency number. The method of claim 2, wherein said emergency number is 911 and said matching step comprises the substeps of: determining whether the first digit of the dialed number is 9; and if the first digit of the dialed number is determined as 9, determine whether each of the second digit and the third digit of the dialed number is 1. The method of claim 2, wherein said emergency number is 0911 and said comparison step comprises the substeps of: determining if the first digit of the dialed number is 0; if the first digit of the dialed number is 0, determine if the second digit of the dialed number is 9; and if the second digit of the dialed number is 9, determine whether each of the third digit and fourth digit of the dialed number is 1. The method according to claim 2, wherein said emergency number is 1911 and said comparison step comprises the substeps of: determine if the first digit of the dialed number is 1; if the first digit of the dialed number is 1, determine if the second digit of the dialed number is 9; and if the second digit of the dialed number is 9, determine whether each of the third digit and fourth digit of the dialed number is 1. The method according to claim 1, wherein said mobile station is identified by a mobile identification number (MIN). ) and an electronic serial number (ESN) and said determination step if said call is indicated as fraudulent comprises the step of determining whether said MIN / ESN pair is valid. The method according to claim 1, wherein said mobile station is identified by a mobile identification number (MIN) and an electronic serial number (ESN), and -this step of determining whether said call is indicated as fraudulent comprises the ' step of determining if said MIN / ESN pair is indicated as occupied in another call. The method according to claim 1, wherein each of said system and said mobile station generates an authentication response, the authentication response generated in said mobile station is sent to said system, and said step of determining whether said call is indicated as fraudulent comprises the step of determining whether the authentication response sent from said mobile station corresponds to the authentication response generated in said system. The method according to claim 8, wherein said authentication responses are generated from the shared secret data (SSD) stored in each of said system and said mobile station, respectively, and said fraud handling procedure comprises the SSD update in said mobile station. The method according to claim 1, wherein said fraud handling method comprises blocking said call. A method of processing calls in a wireless communication system, the method comprises the steps of: detecting a call made from a mobile station in said system to a multi-digit number dialed by a user of said mobile station; determine if said dialed number is a predefined multi-digit emergency number; if said dialed number is determined as an emergency number, carry out said call; if said dialed number is not determined as an emergency number, determine if said call is indicated as fraudulent; if said call is not indicated as fraudulent, make the call; and if said call is indicated as fraudulent, invoke a predetermined fraud handling procedure selected by an operator of said system. The method according to claim 11, wherein said step of determining whether said dialed number is an emergency number comprises the step of collating the digits of the dialed number with the digits of said emergency number. The method of claim 12, wherein said emergency number is 911 and said matching step comprises the substeps of: determining whether the first digit of the dialed number is 9; and if the first digit of the dialed number is 9, determine if each of the second digit and third digit of the dialed number is 1. The method of claim 12, wherein said emergency number is 0911 and said comparison step comprises the substeps of: determine if the first digit of the dialed number is 0; if the first digit of the dialed number is 0, determine if the second digit of the dialed number is 9; and if the second digit of the dialed number is 9, determine whether each of the third digit and fourth digit of the dialed number is 1. 15. The method according to claim 12, wherein said emergency number is 1911 and said check step it includes the substeps of: determining if the first digit of the dialed number is 1; if the first digit of the dialed number is 1, determine if the second digit of the dialed number is 9; and if the second digit of the dialed number is 9, determine whether each of the third digit and fourth digit of the dialed number is 1. 16. The method according to claim 11, wherein said mobile station is identified by a mobile identification number. (MIN) and an electronic serial number (ESN), and said step of determining whether said call is indicated as fraudulent comprises the step of determining whether said MIN / ESN pair is valid. The method according to claim 11, wherein said mobile station is identified by a mobile identification number (MIN) and an electronic serial number (ESN) and said step of determining whether said call is indicated as fraudulent comprises the step to determine if said MIN / ESN pair is indicated as occupied in another call. The method of claim 11, wherein each of said system and said mobile station generates an authentication response, the authentication response generated in said mobile station is sent to said system, and said step of determining whether said call is indicated as fraudulent comprises the step of determining whether the authentication response sent from said mobile station corresponds to the authentication response generated in said system. 19. The method according to claim 18, wherein said authentication responses are generated from shared secret data (SSD) stored in each of said system and said mobile station, respectively, and said fraud management procedure comprises updating of SSD in said mobile station. 20. The method according to claim 11, wherein said fraud handling method comprises blocking said call. The method according to claim 11, further comprising the step of determining whether said call is indicated as fraudulent if said dialed number is determined as an emergency number, and where said call is made if said dialed number is determined as an emergency number even when said call is indicated as fraudulent. 22. In a wireless communication network, a call processing system comprising: a device for detecting a call established from a mobile station in said network to a multi-digit number dialed by a user of said mobile station; a device to determine if said call is indicated as fraudulent; a device for determining whether said dialed number is a predefined multi-digit emergency number; a device to make this call if said call is indicated as non-fraudulent or if said dialed number is determined as an emergency number even when said call is indicated as fraudulent; and a device to block said call if said call is indicated as fraudulent and said dialed number is not determined as emergency. 23. The system of claim 22, wherein said device for determining whether said dialed number is an emergency number comprises a device for collating the digits of the number dialed with the digits of said emergency number. The system according to claim 22, wherein said mobile station is identified by a mobile identification number (MIN) and an electronic serial number (ESN) and said device for determining whether said call is indicated as fraudulent comprises a means to determine if said MIN / ESN pair is valid. 25. The system according to claim 22, wherein said mobile station is identified by a mobile identification number (MIN) and an electronic serial number (ESN) n and said means for determining whether said call is indicated as fraudulent comprises a means to determine if said MIN / ESN pair is indicated as busy in another call. The system of claim 22, wherein each of said network and said mobile station generates an authentication response, the authentication response generated in said mobile station is sent to said network, and said device to determine if said call is indicated as fraudulent. it comprises a means for determining whether the authentication response sent from said mobile station corresponds to the authentication response generated in said network.