CA1236532A - Method of detecting the unauthorized use of an identification assigned to a mobile radio station in a radio transmission system - Google Patents
Method of detecting the unauthorized use of an identification assigned to a mobile radio station in a radio transmission systemInfo
- Publication number
- CA1236532A CA1236532A CA000482867A CA482867A CA1236532A CA 1236532 A CA1236532 A CA 1236532A CA 000482867 A CA000482867 A CA 000482867A CA 482867 A CA482867 A CA 482867A CA 1236532 A CA1236532 A CA 1236532A
- Authority
- CA
- Canada
- Prior art keywords
- radio station
- mobile radio
- data
- exchange
- radio
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W12/00—Security arrangements; Authentication; Protecting privacy or anonymity
- H04W12/12—Detection or prevention of fraud
- H04W12/126—Anti-theft arrangements, e.g. protection against subscriber identity module [SIM] cloning
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W12/00—Security arrangements; Authentication; Protecting privacy or anonymity
- H04W12/60—Context-dependent security
- H04W12/69—Identity-dependent
- H04W12/72—Subscriber identity
Abstract
ABSTRACT
The identification of a mobile radio station in a radio transmission system can be based on a subscriber's number assigned to the mobile radio station which sub-scriber number is registered in, for example, the tele-phone directory and on an identification code which is formed in accordance with a secret enciphering rule from the subscriber number. By copying the identification signal generator, for example, a magnetic card on which the subscriber's number and the identification code are stored, or by listening-in on the exchange of information via the radio transmission channel between a mobile radio station and a stationary radio station (radio exchange) an intended fraudulent user can imitate and use an external identifi-cation. So as to enable detection of this imitation addi-tional data which change during operation of the mobile radio station are combined with fixed data, which depend on the different procedures in the system (subscriber's number and identification code of the mobile radio station, and are evaluated in the radio exchange. Such variable data can be constituted by, for example, the number of successful accesses of the mobile radio station to a radio transmission channel. There may be a fixed or a variable relationship between the number of radio messages and the number of fixed data, assigning being time-dependent in the event of a variable assigning, because of the depen-dence on the number of accesses of the mobile radio station onto the radio transmission channel.
The identification of a mobile radio station in a radio transmission system can be based on a subscriber's number assigned to the mobile radio station which sub-scriber number is registered in, for example, the tele-phone directory and on an identification code which is formed in accordance with a secret enciphering rule from the subscriber number. By copying the identification signal generator, for example, a magnetic card on which the subscriber's number and the identification code are stored, or by listening-in on the exchange of information via the radio transmission channel between a mobile radio station and a stationary radio station (radio exchange) an intended fraudulent user can imitate and use an external identifi-cation. So as to enable detection of this imitation addi-tional data which change during operation of the mobile radio station are combined with fixed data, which depend on the different procedures in the system (subscriber's number and identification code of the mobile radio station, and are evaluated in the radio exchange. Such variable data can be constituted by, for example, the number of successful accesses of the mobile radio station to a radio transmission channel. There may be a fixed or a variable relationship between the number of radio messages and the number of fixed data, assigning being time-dependent in the event of a variable assigning, because of the depen-dence on the number of accesses of the mobile radio station onto the radio transmission channel.
Description
"Method of detecting the unauthorized use of an identifi-cation assigned to a mobile radio station in a radio transmission system."
The invention relates to a method of detecting the unauthorized use of an identification assigned to a mobile radio station in a radio transmission system as claimed in the introductory part of the Patent Claim 1.
~i-th radio transmission systems cost registrat-ion for telephone conversations via a moblle radio s-ta-tion is effected in an exchange. For all domestic calls a uniform rate is used and for calls abroad the rates are used which are valid for international-direct subscriber dialling services. In additlon to -these call fees there is an extra fee for the use of a radio transmission channel.
The data of all successful and attempted calls are, for example, recorded on magnetic tape in the ex-change. In addition to other statistical details the fol-lowing data are also recorded: data on -the radio trans-mission arrangemen-t effecting a call set-up, the tim0, the call fees~ -the identification of the mobile radio station7 the diallecl subscriber~s number - for example the call n~m'ber of a subscriber station of -the public -telephone 20 network - when the call is made from the mobile station to the stationary sta-tion, the reasons why the comlection has not been es-tablished and -the channel number of -the radio transmission channel~
German Paten-t Specification 2~ 19 615 discloses 25 a method o~ identifying a subscriber's station (mobile radio station) by means of which the unauthorized use of the identification (subscriber number and identifica-tion code) of the mobile radio station in the radio transmission sys-tem can be detected. The moblle radio station comprises 30 inter alia an identification code memory. ~ magne-tic car~l, ~hich is in the form of a check card and contains t~
essential data ~n a rnaglletic strip, can, -for example, be used as an iden-tification code mernor~. To enable operation ~23~532 PHD 84 326 7~5-1985 of the mobile radio sta-tion, the identifica-tion code memory card is inserted into a slot of the control unit of the mobile radio station and t;he data are read by a read unit of the control unit and applied to a control arrangement in the control unit. To prevent fa~e coples of the ma~-ne-tic cards from being made using detail~s from the tele-phone directory, a second "secret" subscriber's number (identifica-tion code) :is assigned to each subscriber on the magnctic card.
To check the idendity, it is checked whether a re identification signal and the subscriber's number are in ag*eement. Then, the identification signal trans~it-ted by a mobile radio station to allow checking of its iden-tidy, wh:ioh identification signal i~s Pormed by a code unknown to the subscriber from the subscriber's number, is transmitted to the exchange. In the exchange the iden-tification signal received from the mobile subscriber's station is decoded using the opposite code. The decoding operation provides by way of re-identification the call 20 number (subscriber's number) of the relevan-t mo'bile radio station.
Forged identifications, that is -to say iden-ti-fications wh:ich are ~ormed wi-thout the use of the en-coding rule which is unknown to the su'bscriber, are indeed 25 also deooded :Ln the exchange and transm:itted as a re~
identification signal to the mobile station. ~Iowever, the re~identification thlls obtained is not in agreement with the re-~dentification corresponding to the subscriber's number of the mobile radio station. The re-identification 30 signal received in the mobile radio station is compared wi-th the subscriber~s number - which is, for example, recorded on the magnetic card - and when it is found that there is no agreement in the re-identification signal receiver the call connection se-t-up in the mobile radio 35 station is discontinued.
Such a method, in which a fixed encoding rule is used, hard,y offers however any protection against forged identifications obtained by copying the identification code ~236S3'~
PIID ~4 326 3 7-5-1985 generator of the mobile radio station or by listening-in on the exchange of information via the radio transmission channel. If the exchange of information via the radio transmission channel is listened-in to~ then by manipulating 5 the iden-tification code generator~ that is to say, fo-r example, the magnetic card, and by tampering with the identification code receiver in the mobile radio station, it is possible to operate the mobile rad o station with an external identification code a~d the call charges for this mobile rad:io station are charged to the account of another subscriber of the radio transmission systems.
It is an object of the invention to extend the method disclosed in German Patent Specifica-tion 24 19 615 in such a way that it is no longer possible -tha-t call chc~rges are charged to the account of other subscribers of the radio transmission system by using false identif-L-cation codes obtained in an unauthorized manner by copy-ing the ident:ifica-tion code generator of the mobile radio station or by listening-in on the exchange of information on the radio transmission channel.
This object is accomplished by the measures described in the charac~erizing part of the Pat~n-t Clairrl 1.
Manipulated icLen-tifications can be obtained in an unauthorized manner by copying the stored fixed data or by listening--in on the exchange of information over -t~
transmission channel. In the first case -the unauthorized use of the fixed data of a mobile radio station can be detected by combining fixed data, such as the subscriber's numbe r and identification code, with variable data. Even if the stored fixed data are copied, the manipulator cannot make calls at the expense of another subscriber as he does not know the stored variable data. Making calls at the ex-pense of other subscribers of the radio transmlssion system is only pos,ible after copying of the stored fixed da-ta and o-verhearing the variable data. However, -the variable data are changed during operation of the two mobile radio stations, so that in certain circumstances such fraudulent use might no-t be detected the first -time a call is made.
. ~
~LZ~65~
PIID 84 326 Ll 7-5-1905 During further operation of the two mobile radio stations unequal variable data are produced which result in dif-ferent comparison results in the radio exchange, Con-sidered over a longer period of time~ the fraudulent user cannot carry on conversations anymore without these mani-pulations being detected.
In a majority of cases false identification codes are obtained in an unauthorized manner by listening-in on the exchange of information on the radio transmission channel (second case). Given the fact that data are used which depend on the system operation, the manipulator must listen-in a long time on the exchange of information over the radio transmission channel for a very long time to acquire knowledge of the different fixed data assigned to the different radio messages (or the number of times the channel is accessed), I~ a method as claimed in the Patent Claim 2, the mobile radio station is only required to supply second fixed data s-tored in the mobile radio station (for example 20 the identification code) when there is inequality between the variable data. The first and second identification code~ can be optionally agreecl. A fraudulent user cannot o~erhear the second identificatlon code of the authorizecl mobile raclio sta-t:Lon since this second identifioation 25 code :Ls otherw~se not transmitted~ so that checking the socond identi~ication code in the radio exchange by com-paring it with the identifica-tion code transmitted by the fraudulent user results in an alarm.
If the fraudulent user has obtained the fixed 30 data by copying the memory, then upon subsequent operation of the mobile radio station different variable data occur in the two mobile stations. As claimed in Claim ~, when there i5 inequality between the variable data, the sub-scriber number dialled by the mobile radio station are 35 stored. By calling back to these subscribers it is possible to detect fraudulent use in a simple way using simple means.
If, as claimed in Claim 4~ the number of success-. "
lZ3~;53Z
PHD 8L1 326 5 7~ 1985 ful accesses to the mobile radio station (entering, andcost charging, free-channel number transmission) are used as the varia~le data, then the comparison and evaluation procedure in the radio exchange can also be effected in a simple way. With each successful access the counting position of a counter provided in the mob le radio station and also a counter assigned in the radio exchange to this mobile radio station is incremented by, for example, 1.
The comparison of variable data can also be effected in a simple manner.
A further simplification is accomplished when, as claimed in Claim 5 only a portion of the counting po-sition is transmitted when the connection from the mobile radio station is set-up. In the case of inequality between these portions~ the total counting position of the counters in the mobile radio station is transmitted with o-ther fixed data to the exchange and the counter present there is adjusted to this counting position so that a brief interference has no effect on the further operation of the 20 mobile radio station.
There are only a predetermined number of differ-ent radio messages for the overall procedure. Given the fact that it is sufficient -to choose the number of differ-ent fixed data assigned to the mobile radio s-tation to be 25 not more than e~ual to the number of all the di~ferent radio messages~ -the volume of the fixed data can be lim:ited (Claim 11). The assignment of data between the radio message and the fixed data may be fixed or variable (Claims 12, 13). When the assignment is variable, it is 30 in practice hardIy possible for an unauthorized user, also when he listens for a long period of ti~ to the ex-change of information over the transmission channel, to detect the rules governing the assignment of data~ when after each successful access a different assignment is 35 used (Claim 13). Such assigning rules can be laid down n a simple manner when, starting from the first access during operation of the system ("entering~ the access), further accesses after each successful access are effected using . . . . .
3~53Z
PI-ID 8L~ 326 7-5-1985 different fixed data, for example -the subsequen-t data stored in the memory.
The invention will now be described in grea-ter detail by way of example with reference to the embodiment shown in the drawing. Therein:
Figure 1 shows the block circuit diagram of a radio transmission system and Figures 2a and 2b shows -the assigning of radio messages and access, respectively and fixed data in accordance with the invention.
Figure 1 shows the arrangements, used in a method according to the invention, provided in a mobile radio sta-tion MS and a radio exchange BS.
The radio exchanges BS are often spatially arranged in a radio transrnission system in accordance with a cellular system A plurality of duplex-transm ssion channels, alternatively referred to as radio channels, are assigned to each radio exchange. At least one of these channels, the service channel, is used for signalling pur-20 poses for the control of the system fwlctions. Thesesystem functions comprise, for example, the transmission of free-channel numbers during the call set-up from and to the mobile radio sta-tion, as well as reports about the whereabouts of the mobile radio station~ to report thelr availability. Each service channel may be divided Ln each transmission direction into a sequ~nce of time slots of equal lengths. Assigned to each time slot in the return direction, that is to say from the radio exchange BS -to the mobile radio station MS, is a later time slot 30 in the forward direction, tha-t is to say from the mobile radio station MS to the radiG exchange BS. In the return direction the radio exchange BS continuously transmits reports of a fixed duration, this duration being equal to the duration of a -time slot. These reports comprise 35 marks which provide information about the use of the time slots of the forward direction~ assigned to the mobile station MS.
If a mobile radio station MS wants to access ~236S3;~
P~ID 84 326 7 7-5-1985 the ser~ice channel and a call set-up must be ef~ected, then bv means of a request for identification the radio exchange requires the mobile radio station MS to transmit the selection information by way of identifica-tion~ For the purpose of identification of the mobile radio sta-tion the fixed data, for example the first subscriber's number mid 1 and the first identification code K1 of -the mobile radio station MS stored in a s-tore SP~ are transmitted to the radio exchange BS during the call set-ting-up stage.
The mobile radio station MS comprises a control STMS
which inter alia reads the memory SP and transmits the stored fixed data using a transmitter SMS. In radio transmission systems it is often laid down that, in the direction from the radio exchange PS -to the mobile radio station MS, the identification code K assigned to the mobile radio station MS is no-t transmitted.
The transmitted fixed data are received by a receiver EBS provided in the exchange BS, and applied to a central con-trol unit STBS. In the stationary radio 20 station the fixed da-ta stored there in a data file D
with the aid of the control unit STBS, is compared there with the received fixecl data and evaluated. In a methocL
disclosed in Gerrnan Patent Specification 24 19 615 an acknowledge s:ignal is transmitted to the mo'bile radio 25 sta-tlon MS when there is agreement between the fixed data f`rom the radio exchange BS and the connec-tion is established~ the radio exchange assigrning a speech channel selected for the conversation to the mobile radio station MS by means of a channel command.
In the method according to the invention addit-ional data which change during operation of the mobile radio station MS are stored in the mobile radio s-tation.
In -the embodiment shown in Figure 1, the number of success-ful accesses of the mobile radio station MS are used as 35 the variable data. The counting posi-tion of a counter ZMS1 provided in -the mobile radio station MS is incremeneted, for example by 1, at each successful access. The counting positions, which can be taken from -the outputs QO -to Qn are nZ, .
~Z3653~
interrogated by the control unit STMS and transmitted to the radio exchange BS via the transmitter SMS.
The radio exchange BS comprises a counter ZBS1 which is assigned to this mobile radio station MS. The counting position of the counter ZBS1 is, for example, incremented by one by means of the central control unit STBS at each successful access of this mobile radio station MS. The counting positions of the counters ZMS1 and ZBS1 may alternatively be increased by linearly in-creasing steps, it then being necessary that the size ofthe step used last in the mobile radio station ~IS or in the radio exchange BS is known. Increasing the step size may be effected cyclically, it -then being possible to use a counter to determine the at that instant actual step size.
To set~up a conversation, an identification, formed by fixed data such as, for example, the subscriber's number mid and identification code K and variable data, i _ the counting position of the counter ZSM1~ are 20 transmitted under -the control of the control unit STMS to the radio exchange BS and compared there wi-th the fixed data stored in a data file D~ the subscriber~s number mid and identlfication code K, and also with -the counting posi.-tlon of the counter ZBS1.
As variable data~ the mobile radio station MS
can, for example, only transmit a portion of the counting posi-tion~ obtained by selecting predetermined bit positions of the counting position or by combining the counting position .with a key (for example E~OR-combination). If a 30 fraudulen-t user listens-in on the exchange of information via the radio transmi.ssion channel, he can only ov~rhear a portion of the counting position, but not the whole counting position. Consequently, the fraudulent user can only try and guess the total counting position, so 35 that as a rule his first trial can already be detected.
If the fixed data, subscriber~s.number mid and identification code K transmit-ted by the mobile radio station MS, do no-t agree with the fixed data, the sub-;3~
P~ID 8~ 326 9 7-~-198~
scriber's number mid and the iden-tlfication code K stored in data file D, then the radio exchange BS ignores the report from the mobile radio station MS.
If the subscriber~s number mid~ identification code K and the variable data, for example, the counting position, are equal to each other then the connection is established.
If the counters ZMS1 and ZBS1 have different counting positions, for example the positions ZMS1 = 38 l and ZBS 1 = 20, shown in the drawing, that is to say the variable data are unequal, then the radio exchange BS
requests the mobile station MS by means of an identifica-tion command to supply a further identification~ consist-ing, for example, of the fixed data mid5 and/or the iden-tification code K5 and the complete counting position(variable data). The radio exchange BS compares the received fixed data mid5 and/or identification code K5) with the fixed data s-tored in the store SP.
If the fixed data do not agree, then the central control STBS triggers an alarm.
If the fixed data are in agreement, then the cen-tral control STBS adJusts -the coun-ter ZBS1 -to the counting position of the oounters ZMS1 of the mobile radio statlon MS. ~-t each subsequent and successful access the two countLng positLons are :Lncremeneted by 1. The sub-scrlber's numbers and the coun-ting position selected by the mobile radio sta-tion MS are stored ln the radio ex-change BS . If during the subsequen-t accesses the counting positlons are in agreement, then the subscriber numbers 30 selected by the mobile radio station MS are removed from a store.
When also the subsequent comparisons have a negative result, no connection is established for the mobile radio st~tion MS. Using the subsdriber numb~rs pre-~5 viously dialled by fraudulent users, it is possible tode-tect the name and consequently the fraudulent user by making inquiries at these subscribers. Any error in the mobile radio station MS can then be eliminated.
f~r~
P~ID 8~ 326 10 7-5-198~
To simplify the evaluation procedure of -the counting positions ZMS1 and ZBS1 only a portion of the binary encoded counting position may be included in the comparison operation. For setting the counter ZBS1 to the counting position of the counter ZMS1 the mobile radio station MS is requested by the radio exchange BS to supply the complete counting position. Thus~ it can be achieved that normally the report is short and the transmission capacity of the service channel is fully utilized for a plurality of mobile radio stations MS.
For a number M of mobile radio stations MS a counter ZBSx (x = 1, ..., M) is provided in the radio exchange BS. The drawing illustrates this for a second mobile radio station MS by a counter ZBS2.
Obtaining identifications and assigning them to a mobile radio station MS is further made more diffi-cult in that fixed data which depend on the different procedures in the system are assigned to each mobile radio station MS in addition to the variable data. The fraudulent 20 user must listen-in for a long periocl of time on the exchange of information on the radio transmission channel -to know the different fixed data assigned to -the mobile radio station ~S. ~Iring the different procedures in the system there are only a predetermined number of different 25 radio messages, of which Figure 2a shows, for example, the messages "enter into store"~ "remove from s-tore"~ ... .
With a view to limiting the data volume of fixed data, the number of different, fixed da-ta assigned to the mobile radio station MS can be chosen to be equal to the number 30 of different radio messages~
The assignment between the radio message and the fixed data, as shown in ~igure 2a, may be a fixed assignment. Entering the data of the mobile radio station MS into or removing them from interior and foreign data 35 filed of the radio exchanges BS is effected, for example, as soon as the fixed data "mid1, K1" or "mid2, K2l'-trans-mi-tted as a constituent part of the identification for the radio messages "enter into store" or "remove from s-tore"
.:, PIID 8~ 326 11 7-~-138~
agree to the fixed da-ta stored in the data file D of the radio exchange BS.
To provide a variable assignment of radio message and fixed data, more specifically to provide a time-dependent assignment, it is possible, as shown in Figure 2, to have each successful access be succeeded by an access with o-ther fixed data. To simplify the laying-down of assignment instructions, it can be agreed tha-t the first access of -the mobile radio station MS to the radio transmission channel, usually the radio message "en-ter into store", is effected using first fixed data9 formed by the first subscriber's number mid1 and the first iden-tification code K1. The second access of the mobile radio station MS during a system procedure 9 for example for "removing data from store" or "star-t dialling procedure", is then effected using a second subs~riber~s number mid2 and a second identification code K2. As a fraudulent user does not known how many times the mobile radio s-tation MS has been accessed, assigning -the fixed da-ta is hardly 20 possible. Sending identifications by trial and error using random fixed data usually results in an alarm report in -the radio exchange BS and storage of the subscri'ber's numbers dialled by the fraudulent user, so that 'by call-:ing bacl~ to said subscribers the frauclulent user can 'be 25 found in a simple way.
The invention relates to a method of detecting the unauthorized use of an identification assigned to a mobile radio station in a radio transmission system as claimed in the introductory part of the Patent Claim 1.
~i-th radio transmission systems cost registrat-ion for telephone conversations via a moblle radio s-ta-tion is effected in an exchange. For all domestic calls a uniform rate is used and for calls abroad the rates are used which are valid for international-direct subscriber dialling services. In additlon to -these call fees there is an extra fee for the use of a radio transmission channel.
The data of all successful and attempted calls are, for example, recorded on magnetic tape in the ex-change. In addition to other statistical details the fol-lowing data are also recorded: data on -the radio trans-mission arrangemen-t effecting a call set-up, the tim0, the call fees~ -the identification of the mobile radio station7 the diallecl subscriber~s number - for example the call n~m'ber of a subscriber station of -the public -telephone 20 network - when the call is made from the mobile station to the stationary sta-tion, the reasons why the comlection has not been es-tablished and -the channel number of -the radio transmission channel~
German Paten-t Specification 2~ 19 615 discloses 25 a method o~ identifying a subscriber's station (mobile radio station) by means of which the unauthorized use of the identification (subscriber number and identifica-tion code) of the mobile radio station in the radio transmission sys-tem can be detected. The moblle radio station comprises 30 inter alia an identification code memory. ~ magne-tic car~l, ~hich is in the form of a check card and contains t~
essential data ~n a rnaglletic strip, can, -for example, be used as an iden-tification code mernor~. To enable operation ~23~532 PHD 84 326 7~5-1985 of the mobile radio sta-tion, the identifica-tion code memory card is inserted into a slot of the control unit of the mobile radio station and t;he data are read by a read unit of the control unit and applied to a control arrangement in the control unit. To prevent fa~e coples of the ma~-ne-tic cards from being made using detail~s from the tele-phone directory, a second "secret" subscriber's number (identifica-tion code) :is assigned to each subscriber on the magnctic card.
To check the idendity, it is checked whether a re identification signal and the subscriber's number are in ag*eement. Then, the identification signal trans~it-ted by a mobile radio station to allow checking of its iden-tidy, wh:ioh identification signal i~s Pormed by a code unknown to the subscriber from the subscriber's number, is transmitted to the exchange. In the exchange the iden-tification signal received from the mobile subscriber's station is decoded using the opposite code. The decoding operation provides by way of re-identification the call 20 number (subscriber's number) of the relevan-t mo'bile radio station.
Forged identifications, that is -to say iden-ti-fications wh:ich are ~ormed wi-thout the use of the en-coding rule which is unknown to the su'bscriber, are indeed 25 also deooded :Ln the exchange and transm:itted as a re~
identification signal to the mobile station. ~Iowever, the re~identification thlls obtained is not in agreement with the re-~dentification corresponding to the subscriber's number of the mobile radio station. The re-identification 30 signal received in the mobile radio station is compared wi-th the subscriber~s number - which is, for example, recorded on the magnetic card - and when it is found that there is no agreement in the re-identification signal receiver the call connection se-t-up in the mobile radio 35 station is discontinued.
Such a method, in which a fixed encoding rule is used, hard,y offers however any protection against forged identifications obtained by copying the identification code ~236S3'~
PIID ~4 326 3 7-5-1985 generator of the mobile radio station or by listening-in on the exchange of information via the radio transmission channel. If the exchange of information via the radio transmission channel is listened-in to~ then by manipulating 5 the iden-tification code generator~ that is to say, fo-r example, the magnetic card, and by tampering with the identification code receiver in the mobile radio station, it is possible to operate the mobile rad o station with an external identification code a~d the call charges for this mobile rad:io station are charged to the account of another subscriber of the radio transmission systems.
It is an object of the invention to extend the method disclosed in German Patent Specifica-tion 24 19 615 in such a way that it is no longer possible -tha-t call chc~rges are charged to the account of other subscribers of the radio transmission system by using false identif-L-cation codes obtained in an unauthorized manner by copy-ing the ident:ifica-tion code generator of the mobile radio station or by listening-in on the exchange of information on the radio transmission channel.
This object is accomplished by the measures described in the charac~erizing part of the Pat~n-t Clairrl 1.
Manipulated icLen-tifications can be obtained in an unauthorized manner by copying the stored fixed data or by listening--in on the exchange of information over -t~
transmission channel. In the first case -the unauthorized use of the fixed data of a mobile radio station can be detected by combining fixed data, such as the subscriber's numbe r and identification code, with variable data. Even if the stored fixed data are copied, the manipulator cannot make calls at the expense of another subscriber as he does not know the stored variable data. Making calls at the ex-pense of other subscribers of the radio transmlssion system is only pos,ible after copying of the stored fixed da-ta and o-verhearing the variable data. However, -the variable data are changed during operation of the two mobile radio stations, so that in certain circumstances such fraudulent use might no-t be detected the first -time a call is made.
. ~
~LZ~65~
PIID 84 326 Ll 7-5-1905 During further operation of the two mobile radio stations unequal variable data are produced which result in dif-ferent comparison results in the radio exchange, Con-sidered over a longer period of time~ the fraudulent user cannot carry on conversations anymore without these mani-pulations being detected.
In a majority of cases false identification codes are obtained in an unauthorized manner by listening-in on the exchange of information on the radio transmission channel (second case). Given the fact that data are used which depend on the system operation, the manipulator must listen-in a long time on the exchange of information over the radio transmission channel for a very long time to acquire knowledge of the different fixed data assigned to the different radio messages (or the number of times the channel is accessed), I~ a method as claimed in the Patent Claim 2, the mobile radio station is only required to supply second fixed data s-tored in the mobile radio station (for example 20 the identification code) when there is inequality between the variable data. The first and second identification code~ can be optionally agreecl. A fraudulent user cannot o~erhear the second identificatlon code of the authorizecl mobile raclio sta-t:Lon since this second identifioation 25 code :Ls otherw~se not transmitted~ so that checking the socond identi~ication code in the radio exchange by com-paring it with the identifica-tion code transmitted by the fraudulent user results in an alarm.
If the fraudulent user has obtained the fixed 30 data by copying the memory, then upon subsequent operation of the mobile radio station different variable data occur in the two mobile stations. As claimed in Claim ~, when there i5 inequality between the variable data, the sub-scriber number dialled by the mobile radio station are 35 stored. By calling back to these subscribers it is possible to detect fraudulent use in a simple way using simple means.
If, as claimed in Claim 4~ the number of success-. "
lZ3~;53Z
PHD 8L1 326 5 7~ 1985 ful accesses to the mobile radio station (entering, andcost charging, free-channel number transmission) are used as the varia~le data, then the comparison and evaluation procedure in the radio exchange can also be effected in a simple way. With each successful access the counting position of a counter provided in the mob le radio station and also a counter assigned in the radio exchange to this mobile radio station is incremented by, for example, 1.
The comparison of variable data can also be effected in a simple manner.
A further simplification is accomplished when, as claimed in Claim 5 only a portion of the counting po-sition is transmitted when the connection from the mobile radio station is set-up. In the case of inequality between these portions~ the total counting position of the counters in the mobile radio station is transmitted with o-ther fixed data to the exchange and the counter present there is adjusted to this counting position so that a brief interference has no effect on the further operation of the 20 mobile radio station.
There are only a predetermined number of differ-ent radio messages for the overall procedure. Given the fact that it is sufficient -to choose the number of differ-ent fixed data assigned to the mobile radio s-tation to be 25 not more than e~ual to the number of all the di~ferent radio messages~ -the volume of the fixed data can be lim:ited (Claim 11). The assignment of data between the radio message and the fixed data may be fixed or variable (Claims 12, 13). When the assignment is variable, it is 30 in practice hardIy possible for an unauthorized user, also when he listens for a long period of ti~ to the ex-change of information over the transmission channel, to detect the rules governing the assignment of data~ when after each successful access a different assignment is 35 used (Claim 13). Such assigning rules can be laid down n a simple manner when, starting from the first access during operation of the system ("entering~ the access), further accesses after each successful access are effected using . . . . .
3~53Z
PI-ID 8L~ 326 7-5-1985 different fixed data, for example -the subsequen-t data stored in the memory.
The invention will now be described in grea-ter detail by way of example with reference to the embodiment shown in the drawing. Therein:
Figure 1 shows the block circuit diagram of a radio transmission system and Figures 2a and 2b shows -the assigning of radio messages and access, respectively and fixed data in accordance with the invention.
Figure 1 shows the arrangements, used in a method according to the invention, provided in a mobile radio sta-tion MS and a radio exchange BS.
The radio exchanges BS are often spatially arranged in a radio transrnission system in accordance with a cellular system A plurality of duplex-transm ssion channels, alternatively referred to as radio channels, are assigned to each radio exchange. At least one of these channels, the service channel, is used for signalling pur-20 poses for the control of the system fwlctions. Thesesystem functions comprise, for example, the transmission of free-channel numbers during the call set-up from and to the mobile radio sta-tion, as well as reports about the whereabouts of the mobile radio station~ to report thelr availability. Each service channel may be divided Ln each transmission direction into a sequ~nce of time slots of equal lengths. Assigned to each time slot in the return direction, that is to say from the radio exchange BS -to the mobile radio station MS, is a later time slot 30 in the forward direction, tha-t is to say from the mobile radio station MS to the radiG exchange BS. In the return direction the radio exchange BS continuously transmits reports of a fixed duration, this duration being equal to the duration of a -time slot. These reports comprise 35 marks which provide information about the use of the time slots of the forward direction~ assigned to the mobile station MS.
If a mobile radio station MS wants to access ~236S3;~
P~ID 84 326 7 7-5-1985 the ser~ice channel and a call set-up must be ef~ected, then bv means of a request for identification the radio exchange requires the mobile radio station MS to transmit the selection information by way of identifica-tion~ For the purpose of identification of the mobile radio sta-tion the fixed data, for example the first subscriber's number mid 1 and the first identification code K1 of -the mobile radio station MS stored in a s-tore SP~ are transmitted to the radio exchange BS during the call set-ting-up stage.
The mobile radio station MS comprises a control STMS
which inter alia reads the memory SP and transmits the stored fixed data using a transmitter SMS. In radio transmission systems it is often laid down that, in the direction from the radio exchange PS -to the mobile radio station MS, the identification code K assigned to the mobile radio station MS is no-t transmitted.
The transmitted fixed data are received by a receiver EBS provided in the exchange BS, and applied to a central con-trol unit STBS. In the stationary radio 20 station the fixed da-ta stored there in a data file D
with the aid of the control unit STBS, is compared there with the received fixecl data and evaluated. In a methocL
disclosed in Gerrnan Patent Specification 24 19 615 an acknowledge s:ignal is transmitted to the mo'bile radio 25 sta-tlon MS when there is agreement between the fixed data f`rom the radio exchange BS and the connec-tion is established~ the radio exchange assigrning a speech channel selected for the conversation to the mobile radio station MS by means of a channel command.
In the method according to the invention addit-ional data which change during operation of the mobile radio station MS are stored in the mobile radio s-tation.
In -the embodiment shown in Figure 1, the number of success-ful accesses of the mobile radio station MS are used as 35 the variable data. The counting posi-tion of a counter ZMS1 provided in -the mobile radio station MS is incremeneted, for example by 1, at each successful access. The counting positions, which can be taken from -the outputs QO -to Qn are nZ, .
~Z3653~
interrogated by the control unit STMS and transmitted to the radio exchange BS via the transmitter SMS.
The radio exchange BS comprises a counter ZBS1 which is assigned to this mobile radio station MS. The counting position of the counter ZBS1 is, for example, incremented by one by means of the central control unit STBS at each successful access of this mobile radio station MS. The counting positions of the counters ZMS1 and ZBS1 may alternatively be increased by linearly in-creasing steps, it then being necessary that the size ofthe step used last in the mobile radio station ~IS or in the radio exchange BS is known. Increasing the step size may be effected cyclically, it -then being possible to use a counter to determine the at that instant actual step size.
To set~up a conversation, an identification, formed by fixed data such as, for example, the subscriber's number mid and identification code K and variable data, i _ the counting position of the counter ZSM1~ are 20 transmitted under -the control of the control unit STMS to the radio exchange BS and compared there wi-th the fixed data stored in a data file D~ the subscriber~s number mid and identlfication code K, and also with -the counting posi.-tlon of the counter ZBS1.
As variable data~ the mobile radio station MS
can, for example, only transmit a portion of the counting posi-tion~ obtained by selecting predetermined bit positions of the counting position or by combining the counting position .with a key (for example E~OR-combination). If a 30 fraudulen-t user listens-in on the exchange of information via the radio transmi.ssion channel, he can only ov~rhear a portion of the counting position, but not the whole counting position. Consequently, the fraudulent user can only try and guess the total counting position, so 35 that as a rule his first trial can already be detected.
If the fixed data, subscriber~s.number mid and identification code K transmit-ted by the mobile radio station MS, do no-t agree with the fixed data, the sub-;3~
P~ID 8~ 326 9 7-~-198~
scriber's number mid and the iden-tlfication code K stored in data file D, then the radio exchange BS ignores the report from the mobile radio station MS.
If the subscriber~s number mid~ identification code K and the variable data, for example, the counting position, are equal to each other then the connection is established.
If the counters ZMS1 and ZBS1 have different counting positions, for example the positions ZMS1 = 38 l and ZBS 1 = 20, shown in the drawing, that is to say the variable data are unequal, then the radio exchange BS
requests the mobile station MS by means of an identifica-tion command to supply a further identification~ consist-ing, for example, of the fixed data mid5 and/or the iden-tification code K5 and the complete counting position(variable data). The radio exchange BS compares the received fixed data mid5 and/or identification code K5) with the fixed data s-tored in the store SP.
If the fixed data do not agree, then the central control STBS triggers an alarm.
If the fixed data are in agreement, then the cen-tral control STBS adJusts -the coun-ter ZBS1 -to the counting position of the oounters ZMS1 of the mobile radio statlon MS. ~-t each subsequent and successful access the two countLng positLons are :Lncremeneted by 1. The sub-scrlber's numbers and the coun-ting position selected by the mobile radio sta-tion MS are stored ln the radio ex-change BS . If during the subsequen-t accesses the counting positlons are in agreement, then the subscriber numbers 30 selected by the mobile radio station MS are removed from a store.
When also the subsequent comparisons have a negative result, no connection is established for the mobile radio st~tion MS. Using the subsdriber numb~rs pre-~5 viously dialled by fraudulent users, it is possible tode-tect the name and consequently the fraudulent user by making inquiries at these subscribers. Any error in the mobile radio station MS can then be eliminated.
f~r~
P~ID 8~ 326 10 7-5-198~
To simplify the evaluation procedure of -the counting positions ZMS1 and ZBS1 only a portion of the binary encoded counting position may be included in the comparison operation. For setting the counter ZBS1 to the counting position of the counter ZMS1 the mobile radio station MS is requested by the radio exchange BS to supply the complete counting position. Thus~ it can be achieved that normally the report is short and the transmission capacity of the service channel is fully utilized for a plurality of mobile radio stations MS.
For a number M of mobile radio stations MS a counter ZBSx (x = 1, ..., M) is provided in the radio exchange BS. The drawing illustrates this for a second mobile radio station MS by a counter ZBS2.
Obtaining identifications and assigning them to a mobile radio station MS is further made more diffi-cult in that fixed data which depend on the different procedures in the system are assigned to each mobile radio station MS in addition to the variable data. The fraudulent 20 user must listen-in for a long periocl of time on the exchange of information on the radio transmission channel -to know the different fixed data assigned to -the mobile radio station ~S. ~Iring the different procedures in the system there are only a predetermined number of different 25 radio messages, of which Figure 2a shows, for example, the messages "enter into store"~ "remove from s-tore"~ ... .
With a view to limiting the data volume of fixed data, the number of different, fixed da-ta assigned to the mobile radio station MS can be chosen to be equal to the number 30 of different radio messages~
The assignment between the radio message and the fixed data, as shown in ~igure 2a, may be a fixed assignment. Entering the data of the mobile radio station MS into or removing them from interior and foreign data 35 filed of the radio exchanges BS is effected, for example, as soon as the fixed data "mid1, K1" or "mid2, K2l'-trans-mi-tted as a constituent part of the identification for the radio messages "enter into store" or "remove from s-tore"
.:, PIID 8~ 326 11 7-~-138~
agree to the fixed da-ta stored in the data file D of the radio exchange BS.
To provide a variable assignment of radio message and fixed data, more specifically to provide a time-dependent assignment, it is possible, as shown in Figure 2, to have each successful access be succeeded by an access with o-ther fixed data. To simplify the laying-down of assignment instructions, it can be agreed tha-t the first access of -the mobile radio station MS to the radio transmission channel, usually the radio message "en-ter into store", is effected using first fixed data9 formed by the first subscriber's number mid1 and the first iden-tification code K1. The second access of the mobile radio station MS during a system procedure 9 for example for "removing data from store" or "star-t dialling procedure", is then effected using a second subs~riber~s number mid2 and a second identification code K2. As a fraudulent user does not known how many times the mobile radio s-tation MS has been accessed, assigning -the fixed da-ta is hardly 20 possible. Sending identifications by trial and error using random fixed data usually results in an alarm report in -the radio exchange BS and storage of the subscri'ber's numbers dialled by the fraudulent user, so that 'by call-:ing bacl~ to said subscribers the frauclulent user can 'be 25 found in a simple way.
Claims (14)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of detecting the unauthorized use of an identification assigned to a mobile radio station in a radio transmission system, in which, when the mobile radio station accesses a message transmission channel, fixed data (subscriber's number, identification code of the mobile radio station) assigned to this mobile radio station are compared in a stationary radio station, more specifically a radio exchange, with available fixed data, characterized in that in the mobile radio station MS and the radio exchange (BS) additional and during operation of the mobile radio station (MS) variable data are available, that during the access the mobile radio station (MS) transmits an identification, formed by fixed data, depend-ing on the system procedures, and variable data and that this identification is compared with data available in the radio exchange (BS).
2. A method as claimed in Claim 1, characterized in that when there is inequality between the variable data, the radio exchange (BS) asks by means of an identification request the mobile radio station (MS) to supply further fixed data stored in the mobile radio station (MS) and compares them with other fixed data also stored in the radio exchange (BS) and that at subsequent accesses it is checked in the radio exchange (BS) whether the further variable data are in agreement.
3. A method as claimed in Claim 1, characterized in that in addition to the variable data also the subscriber's numbers selected by the mobile radio station (MS) are stored in the radio exchange (BS), and that when there is repeatedly inequality between the variable data, a connection is no longer set-up for this mobile radio station (MS).
4. A method as claimed in Claim 1, characterized in that as variable data the number of successful accesses of the mobile radio station (MS) to a radio transmission channel are used and that the counting positions of counters (ZMS1, ZBS1) one of which is provided in the mobile radio station (MS) and the other one in the stati-onary radio station (BS), these counters being assigned to this mobile radio station (MS), are increased at each successful access.
5. A method as claimed in Claim 4, characterized in that only a portion of the counting position is trans-mitted by the mobile radio station (MS) as variable data in the case of access to a transmission channel.
6. A method as claimed in Claims 2 and 4, charac-terized in that together with the other fixed data the complete counting position of the counter (ZMS1) of the mobile radio station (MS) is transmitted to the radio ex-change (BS) and that the counter (ZBS1) arranged in said radio exchange is set to this counting position.
7. A method as claimed in Claim 2, characterized in that the request for identification by the radio ex-change (BS) only consists of a second subscriber's number (mid2).
8. A method as claimed in Claim 1, characterized in that in the mobile radio station (MS) the fixed and variable data are stored on a magnetic card.
9. A method as claimed in Claim 4, characterized in that in the case of access only a portion of the counting position is transmitted as variable data, whilst individual bit positions of the counting positions are selected or the counting position is subjected to combination with a key (for example an EXOR-combination).
10. A method as claimed in Claim 2, characterized in that an identification code of the mobile radio station (MS) is used as the second fixed data.
11. A method as claimed in Claim 1, characterized in that the number of fixed data assigned to each mobile radio station (MS) does not exceed the number of all the different radio messages.
12. A method as claimed in Claim 11, characterized in that the number of assigned fixed data and radio messages is fixed.
13. A method as claimed in Claim 11, characterized in that the number of assigned fixed data and the number of radio messages are variable, whilst a different allo-cation is used after each successful access.
14. A method as claimed in Claim 11 or 13, charac-terized in that the number of assigned fixed data and the number of radio messages depend on the number of successful accesses, that after the mobile radio station (MS) has been switched on the message "enter into store"
is performed with first fixed data (mid1, K1) and that after each successful access the mobile radio station (MS) accesses the radio transmission channel using dif-ferent fixed data (for example mid2, K2).
is performed with first fixed data (mid1, K1) and that after each successful access the mobile radio station (MS) accesses the radio transmission channel using dif-ferent fixed data (for example mid2, K2).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3420460.1 | 1984-06-01 | ||
| DE19843420460 DE3420460A1 (en) | 1984-06-01 | 1984-06-01 | METHOD FOR DETECTING THE UNAUTHORIZED USE OF AN IDENTIFICATION ASSIGNED TO A MOVABLE RADIO STATION IN A RADIO TRANSMISSION SYSTEM |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1236532A true CA1236532A (en) | 1988-05-10 |
Family
ID=6237390
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000482867A Expired CA1236532A (en) | 1984-06-01 | 1985-05-30 | Method of detecting the unauthorized use of an identification assigned to a mobile radio station in a radio transmission system |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0163358B1 (en) |
| JP (1) | JPH0828908B2 (en) |
| AT (1) | ATE63800T1 (en) |
| CA (1) | CA1236532A (en) |
| DE (2) | DE3420460A1 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5420910A (en) * | 1993-06-29 | 1995-05-30 | Airtouch Communications | Mehtod and apparatus for fraud control in cellular telephone systems utilizing RF signature comparison |
| US5557676A (en) * | 1993-11-24 | 1996-09-17 | Telefonaktiebolaget Lm Ericsson | Authentication for analog communication systems |
| GB2318484A (en) * | 1994-03-02 | 1998-04-22 | Fujitsu Ltd | Mobile communication systems |
| US5752189A (en) * | 1994-03-02 | 1998-05-12 | Fujitsu Limited | Mobile communication system which prohibits service to a mobile station having an ID number upon receiving a non-coincidence notice from the mobile station |
| US5950121A (en) * | 1993-06-29 | 1999-09-07 | Airtouch Communications, Inc. | Method and apparatus for fraud control in cellular telephone systems |
Families Citing this family (27)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0793663B2 (en) * | 1986-05-26 | 1995-10-09 | 日本電気株式会社 | Charge control device |
| JPS6352527A (en) * | 1986-08-22 | 1988-03-05 | Matsushita Electric Ind Co Ltd | Selective call method |
| FR2614162B1 (en) * | 1987-04-17 | 1993-12-10 | Flonic Sa | ANALOGUE AUTHENTICATION SYSTEM RECIPROCED BETWEEN A TERMINAL AND A TRANSMISSION LINE |
| FI77550C (en) * | 1987-07-29 | 1989-03-10 | Nokia Mobira Oy | FOERFARANDE FOER SAMMANKOPPLING TILL ANVAENDARENS KORT VID EN MOBILRADIOTELEFON. |
| US4992783A (en) * | 1988-04-04 | 1991-02-12 | Motorola, Inc. | Method and apparatus for controlling access to a communication system |
| JPH02158266A (en) * | 1988-12-12 | 1990-06-18 | Nippon Telegr & Teleph Corp <Ntt> | Connection control system for mobile communication |
| US5239294A (en) * | 1989-07-12 | 1993-08-24 | Motorola, Inc. | Method and apparatus for authenication and protection of subscribers in telecommunication systems |
| SE465800B (en) * | 1990-03-09 | 1991-10-28 | Ericsson Telefon Ab L M | PROCEDURE TO PERFORM PROPERTY CHECKING BETWEEN A BASE STATION AND A MOBILE STATION IN A MOBILE RADIO SYSTEM |
| US5390245A (en) * | 1990-03-09 | 1995-02-14 | Telefonaktiebolaget L M Ericsson | Method of carrying out an authentication check between a base station and a mobile station in a mobile radio system |
| GB9022347D0 (en) * | 1990-10-15 | 1990-11-28 | Smith Myer Communications Limi | System monitoring |
| TR26717A (en) * | 1991-03-01 | 1995-05-15 | Telefonaktienbalagat Lm Ericss | A METHOD FOR PERFORMING A VALIDITY CONTROL BETWEEN A MAIN STATION AND A MOVING STATION IN A MOVING RADIO SYSTEM |
| JPH05300088A (en) * | 1992-04-22 | 1993-11-12 | Fujitsu Ltd | Check system for communication between mobile sets |
| DE4242151C1 (en) * | 1992-12-14 | 1994-03-24 | Detecon Gmbh | Protecting mobile radio, e.g. telephone, against unauthorised use - comparing authentication parameter from input code to stored parameter, only allowing use if they match. |
| US5448760A (en) * | 1993-06-08 | 1995-09-05 | Corsair Communications, Inc. | Cellular telephone anti-fraud system |
| AU679546B2 (en) * | 1993-08-11 | 1997-07-03 | Kabushiki Kaisha Toshiba | Mobile radio communication apparatus |
| DE4336995A1 (en) * | 1993-10-29 | 1995-05-04 | Sel Alcatel Ag | Method and device for determining the assignment of a mobile radio device to device lists |
| DE4416598A1 (en) * | 1994-05-11 | 1995-11-16 | Deutsche Bundespost Telekom | Securing telecommunication connection against unauthorised use |
| US5668876A (en) * | 1994-06-24 | 1997-09-16 | Telefonaktiebolaget Lm Ericsson | User authentication method and apparatus |
| FI108327B (en) * | 1996-12-23 | 2001-12-31 | Nokia Corp | Method of establishing a connection in a mobile network |
| US6073006A (en) * | 1997-05-05 | 2000-06-06 | Motorola, Inc. | Method and apparatus for detecting and preventing fraud in a satellite communication system |
| CA2236086A1 (en) * | 1997-06-12 | 1998-12-12 | At&T Wireless Services, Inc. | User assisted wireless fraud detection |
| AU3348599A (en) * | 1998-03-25 | 1999-10-18 | Telefonaktiebolaget Lm Ericsson (Publ) | System and method of authenticating a mobile station's identity and handling authentication failures in a radio telecommunications network |
| US6754490B2 (en) | 1999-08-27 | 2004-06-22 | At&T Wireless Services, Inc. | International roaming service for permitting a cellular/wireless telephone instrument to access different wireless telephone network/systems |
| GB2362543B (en) * | 2000-05-16 | 2003-12-03 | Sagem | Assembly of a cellular telephone and means for connection to a computer network |
| KR100576910B1 (en) * | 2003-09-27 | 2006-05-03 | 엘지전자 주식회사 | Interception Method For Simultaneous Communication Of Illegality Reproduction Terminal In The Mobile Communication System |
| JP4783615B2 (en) * | 2005-11-08 | 2011-09-28 | 富士通東芝モバイルコミュニケーションズ株式会社 | Mobile communication system |
| BRPI0706880A2 (en) | 2006-01-20 | 2011-04-12 | Verimatrix Inc | system and method for network security |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5915419B2 (en) * | 1980-02-01 | 1984-04-09 | 日本電信電話株式会社 | Method to prevent unauthorized use of mobile devices |
| DE3410936C2 (en) * | 1984-03-24 | 1997-09-18 | Philips Patentverwaltung | Method for recognizing the unauthorized use of an identification assigned to a mobile radio station in a radio transmission system |
-
1984
- 1984-06-01 DE DE19843420460 patent/DE3420460A1/en not_active Withdrawn
-
1985
- 1985-05-29 DE DE8585200857T patent/DE3582899D1/en not_active Expired - Lifetime
- 1985-05-29 EP EP85200857A patent/EP0163358B1/en not_active Expired - Lifetime
- 1985-05-29 AT AT85200857T patent/ATE63800T1/en not_active IP Right Cessation
- 1985-05-30 JP JP60115506A patent/JPH0828908B2/en not_active Expired - Lifetime
- 1985-05-30 CA CA000482867A patent/CA1236532A/en not_active Expired
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5420910A (en) * | 1993-06-29 | 1995-05-30 | Airtouch Communications | Mehtod and apparatus for fraud control in cellular telephone systems utilizing RF signature comparison |
| US5555551A (en) * | 1993-06-29 | 1996-09-10 | Airtouch Communications, Inc. | Method and apparatus for fraud control in cellular telephone systems |
| US5950121A (en) * | 1993-06-29 | 1999-09-07 | Airtouch Communications, Inc. | Method and apparatus for fraud control in cellular telephone systems |
| US6185416B1 (en) | 1993-06-29 | 2001-02-06 | Cellco Partnership | Method and apparatus for fraud control in cellular telephone systems |
| US6219538B1 (en) | 1993-06-29 | 2001-04-17 | Cellco Partnership | Method and apparatus for fraud control in cellular telephone systems |
| US5557676A (en) * | 1993-11-24 | 1996-09-17 | Telefonaktiebolaget Lm Ericsson | Authentication for analog communication systems |
| GB2318484A (en) * | 1994-03-02 | 1998-04-22 | Fujitsu Ltd | Mobile communication systems |
| US5752189A (en) * | 1994-03-02 | 1998-05-12 | Fujitsu Limited | Mobile communication system which prohibits service to a mobile station having an ID number upon receiving a non-coincidence notice from the mobile station |
| US5754959A (en) * | 1994-03-02 | 1998-05-19 | Fujitsu Limited | Mobile communication system with a load balancing feature |
| GB2287614B (en) * | 1994-03-02 | 1998-08-26 | Fujitsu Ltd | Mobile communication systems |
Also Published As
| Publication number | Publication date |
|---|---|
| DE3582899D1 (en) | 1991-06-27 |
| EP0163358A3 (en) | 1987-12-16 |
| EP0163358B1 (en) | 1991-05-22 |
| DE3420460A1 (en) | 1985-12-05 |
| ATE63800T1 (en) | 1991-06-15 |
| EP0163358A2 (en) | 1985-12-04 |
| JPH0828908B2 (en) | 1996-03-21 |
| JPS6129294A (en) | 1986-02-10 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA1236532A (en) | Method of detecting the unauthorized use of an identification assigned to a mobile radio station in a radio transmission system | |
| US4955049A (en) | Method of supervising mobile telephone subscriptions in a mobile telephone system | |
| US5822691A (en) | Method and system for detection of fraudulent cellular telephone use | |
| US5335278A (en) | Fraud prevention system and process for cellular mobile telephone networks | |
| US6434378B1 (en) | Pre-paid cellular telephone system | |
| US5392356A (en) | Mobile telephone terminal and method of preventing unlawful use thereof | |
| US5933773A (en) | Method and a device for mobile telephone supervision | |
| US5390245A (en) | Method of carrying out an authentication check between a base station and a mobile station in a mobile radio system | |
| JP4030588B2 (en) | Search for copied SIM card | |
| CN1087565C (en) | Authentication system and method for preventing wireless communication fraud | |
| EP0909524B1 (en) | Method for allocating a mobile station tmsi | |
| US6038440A (en) | Processing of emergency calls in wireless communications system with fraud protection | |
| EP1157582B1 (en) | Authentication method for cellular communications systems | |
| CA2087433A1 (en) | Method for authentication and protection of subscribers in telecommunication systems | |
| CN1284247A (en) | System and method for authorization of location services | |
| US6466777B1 (en) | Clone terminal detection system and method | |
| CN1279866A (en) | Private base station for mobile phone | |
| WO1991014348A1 (en) | A method of carrying out an authentication check between a base station and a mobile station in a mobile radio system | |
| CA1242501A (en) | Method of recognizing the unauthorized use of an identification | |
| CN1210654A (en) | Use of mobile station as cordless telephone | |
| GB1584579A (en) | Telecommunications system | |
| CN1319362C (en) | Call information output in a telecommunication network | |
| JPH05336109A (en) | Radio communication system | |
| NO163720B (en) | PROCEDURE FOR DETECTING THE UNAUTHORIZED USE OF AN IDENTIFICATION ASSIGNED TO A MOBILE RADIO STATION BY A RADIO TRANSMISSION SYSTEM. | |
| MXPA99010399A (en) | Processing of emergency calls in wireless communications system with fraud protection |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry | ||
| MKEX | Expiry |
Effective date: 20050530 |