MXPA00012451A - Broadcast service access control - Google Patents

Abstract

Techniques and systems for controlling access to information broadcast over point-to-multipoint resources in radiocommunication systems are described. These techniques can be used to provide controllable access to broadcast information services, e.g., security quote services, sports information services, etc., which broadcast services can be provided in conjuction with more conventional cellular radiocommunication services, e.g., voice calls. Exemplary embodiments of the present invention enable subscribing users'equipment to output broadcast information using, for example, either a status variable within the remote equipment or encryption for which subscribing devices have a corresponding decryption key.

Description

DISTRIBUTION SERVICE ACCESS CONTROL BACKGROUND The present invention relates generally to the provision of information services in radiocommunication systems and, more particularly, to techniques for controlling access to broadcast information services provided in conjunction with existing radiocommunication services and systems. The growth of radiocommunications Commercials has been dramatic over the past fifteen years. Callers and cell phones, in particular are now relatively common equipment in many urban facilities. These two different types of communication devices, and support systems have evolved from different fundamental purposes namely, callers to traditionally provide limited information, in a sense to one or more end users and cell phones to traditionally provide two-way voice communication service. As time and technology progress, traditional functional dividing lines between these two different types of radio communication devices have grown callers have acquired some of the functionality that was traditionally provided by cell phones and vice versa. For example, two-way callers have been developed that allow the caller 5 to transmit messages to the call system whose messages can then be sent to other parties. cell phones have acquired the ability to transmit and receive short text messages (v gr, of the order of 160 characters to the fanuméricos) that can appear in the presentation of a cell phone This evolution in radio communication devices has led to the development and market of a host of new information services As services are developed _5 dissemination information for application to conventional cellular systems, the applicant expects that it will be I wish to implement techniques that allow network operators and / or service providers to control access to these new services. Historically, the _y access control / security for wireless services varies between four general types of wireless services (1) point-to-point services, v gr voice connections between two remote terminals, (2 i group calls, v gr, voice connections between more than two remote terminals (3) user services of no end point to multipoint v gr, system control broadcast information, and (4) point to multipoint end user services, v gr, material repeat services, sports scoreboard services etc. Point-to-point services consist of currently, mostly spoken calls made to the landline network or to other mobile users In order to reduce fraud and limit call drop ] _Q authentication and enforcement are now supported in all digital cellular systems, including satellite systems designed for personal communication that will soon be in operation. Each mobile phone (or SIM card in mobile phones operating in accordance with the GSM standard) has a secret key This key is the root for both the authentication and the encryption of the secret key of each user is unique This key, known as the key A in the security specifications promulgated by the Telecornmunications Industry Association (TÍA) can be accessed by the user through a board or sent or generated in the process of a process of Activation Teleservice through the ÍOATS Air) as described in the specifications of TIA In GSM, the key lies in the "smart card" (SIM card) and can not be changed Authentication allows the system to verify the user (or more > specifically the phone or SIM card) Encryption of transmissions also limits the illegitimate use of the system, v gr, sending false information to the mobile station Bilateral authentication where the base station must also verify its legitimacy, reduces the risk of having a illegitimate base station sending false data to mobile > Similar to communication services IQ point-to-point are group calls If the group call is established by having each member assigned to an individual traffic channel, as for a "normal" call between two individuals the key of the individual A based on authentication and encryption can be use and j_5 there is no difference between group calls and conventional voice calls that would require additional protective procedures If there is a common channel assigned to the group, which is feasible in particular in the downlink, all users p must be able of listening to this channel Therefore the downlink encryption in this case can not be based on a key A of a particular user A common encryption key for the group (key G) should be used instead for encryption Each user 5 it can still be authenticated on an individual basis, v gr using the conventional A key However, the encryption key must not be the root key to the A key of either The key G can be input to the mobile station through the board or sent to the mobile station under the protection of the encryption based on normal A key For point-to-multipoint, non-end-user services, the information provided in a > Broadcast control channel (BCCH) in a system cellular there are no protection mechanisms in the current wireless systems This is the case because system designers want to make it fast and easy for mobile stations to find and read the control information found in this type of resource For this type of service there is little or no incentive to prevent non-subscribers from reading the information from > control that is spreading in the BCCH, however techniques can be provided to validate the integrity of the data In this way the encryption for Prevent access of point control channels to multiple points is not needed or provided Point services to multiple end-user points v gr, the material repetition services and title described in the two requests of 2 Utility patent incorporated above, differ from the point-to-point services, non-end-user services in which the service operator does not necessarily need to be the same as the cellular operator, and does not want non-subscribing individuals to be able to read the dissemination of information to subscribers through the Internet. For example, if repeats of material are provided in the broadcast channel, users who do not pay a monthly subscription fee should not be able to access the information. As with dissemination control information, the integrity protection of data may also be desirable for dissemination of data services to subscriber end users. Thus, it can be seen that it would be desirable to provide methods and systems for controlling access to broadcast information services that provide appropriate information integrity and a level of control. of access, where said concerns are balanced against the ease of operation (v gr, faci activation / deactivation of suscpptor) COMPENDI The example modalities of the present invention provide techniques that support control of access to broadcast information services provided through radio communication systems Access control techniques in accordance with the present invention attempt to achieve a number of objectives Specifically, only eligible users should be able to receive services will be simple and easy to allow a service for a particular user It will be simple and fast to disable a service for a particular user, it must be difficult to insert false messages to the broadcast channel or subchannel, it must be possible for the operator to verify a user's claim that he is not able to access a service and for therefore the invoice is being questioned. The end-user's computer v gr mobile station can be a receiving device only, similar to a simple caller, or can be a reception / transmission device, such as a mobile phone In accordance with a purely illustrative example mode of the present invention, the broadcast information service can be a security repeater service which is provided in a system according to IS-136 having broadcast short message service (SMS) capability The portion of the broadcast control channel that has been reserved in IS-136 for SMS can be further separated into a plurality of logical subchannels to carry various portions of the data used to implement the security relay service More specifically, these example subchannels may include a Security Name Channel, a Home Value Channel, and a Delta Channel Access to these channels may be provided using different techniques In accordance with a first example mode, a variable state can be maintained in the remote device that informs the remote device if the user is authorized to have information associated with a particular broadcast service. The remote device checks this variable state and selectively outputs information according to the same A service provider can periodically send training / incapacitation signals to update this variable status. In accordance with another example embodiment of the invention the information transmitted in broadcast channels can be applied. Then, the subscribers will receive periodically you see usable to describe broadcast information BRIEF DESCRIPTION OF THE DRAWINGS The objects and previous features of the present invention will be more evident from the following description of the preferred embodiments with reference to the accompanying drawings, wherein: Figure 1 illustrates a hyperframe structure in accordance with which it can be used to implement the present invention; Figure 2 illustrates the logical channels of the DCCH that can be used to implement the present invention; Figure 3 illustrates exemplary subdivisions of logical channels used to broadcast information associated with a security relay service in accordance with the present invention; Figure 4 illustrates an exemplary radiotelephone system in which the present invention can be implemented; Figure 5 illustrates a signaling timeline used to describe a variable mode example state of the present invention; and Figures 6 and 7 illustrate signaling timelines used to describe an example embodiment of encryption (tachoneo) of the present invention.

DETAILED DESCRIPTION The following description is written in terms of a cellular radiotelephone system, but it will be understood that the applicant's invention is not limited to that environment Likewise, the following description is written in the context that complies with IS-136, TDMA cellular communication systems, but (as mentioned above) it will be understood by those skilled in the art that the present invention can be implemented in other digital communication applications including those that are designed in accordance with other standards, v gr, GSM or PDC, and those that use CDMA as a methodology of In particular, the example modalities of the present invention describe techniques and systems for providing broadcast information services whose access is controlled by the service operator. To provide some context within which to discuss the techniques of broadcasting. access control, we first describe an example broadcast service whose service is intended is directed by an operator using the broadcast resources available in IS-136, in particular the broadcast SMS channel (S-BCCH). Some of the details associated with the IS-136 systems generally and the broadcast SMS channel are specifically described below while that others are omitted to avoid obscuring present invention However, the interested reader may refer to U.S. Patent No. 5 603,081 to Raith et al, and U.S. Patent Application Serial No. 08 / 482,754 also to Raith et al for additional information pertaining to systems related to IS-136 generally and diffusion-specific SMS techniques, respectively The exposures of both US Patent and US Patent Application mentioned above are expressly incorporated herein by reference In example embodiments of Applicant's invention, the transmission of information from base stations to mobile stations is structured in successions of different classes of logical frames Figure 1 illustrates the frame structure of a forward DCCH (base station to mobile station) in accordance with IS-136 and shows two successive hyperframes (HF) each of which preferably comprises a primary superframe (SF) and a respective secondary superframe. It will be recognized, of course, that a hyperframe could include two more superframes Three successive superframes are illustrated in Figure 1, each comprising a plurality of time slots that are organized as logical channels F-BCCH E-BCCH S-BCCH and SPACH which are described with more detail later. At this point, it is sufficient to note that each superframe in a forward DCCH includes a complete set of F-BCCH information (ie, a Layer 3 message set), using as many slots as necessary, and that each superframe begins with one slot F-BXXH. After the F-BCCH slot or slots, the remaining slots in each superframe include one or more (or none) slots for the E-BCCH logical channels. S-BCCH, and SPACH. Referring to Figure 1, and more particularly to Figure 2, each superframe of the downlink DCCH (forward) preferably comprises a broadcast control channel BCCH and a short message service / call / access SPACH channel. The BCCH comprises a fast BCCH (the F-BCCH shown in Figure 1); a prolonged BCCH (the E-BCCH); and a short message service BCCH (the S-BCCH), some of which are used. in general, to carry generic information related to the system from base stations to mobile stations. The logical channel F-BCCH carries critical time system information, so that the structure of the DCCH, other parameters that are essential to gain access to the system, and a change flag of E-BCCH that is described in greater detail in the Patent request of E U A No 08 / 482,754, which is commonly assigned to > incorporated herein by reference, as noted above, a complete set of F-BCCH information is sent in each superframe. The logical channel E-BCCH carries 5 system information that is less critical in time than the information sent in the F- BCCH, a complete set of E-BCCH information (ie, a Layer 3 message set) can expand several superframes and does not need to be aligned to start at the first 0 E-BCCH slot of a superframe. The logical channel S- BCCH carries short broadcast messages, such as material information, announcements and other information of interest to various kinds of mobile subscriber. In accordance with exemplary embodiments of the present invention, this The logical channel may be used to support point-to-multipoint information services, for example, a security relay service, by dividing the S-BCCH channel into at least three logical sub-channels that support this broadcast information service.

Security Name Channel, a Home Value channel and a Delta channel as seen in Figure 3, wherein various portions of the information needed to output repeating information to remote subscriber user devices are - < 5 transmit in each of the three subchannels For more details regarding how these three subchannels S-BCCH are used to provide an example broadcast information service, the interested reader can refer to the patent application of "Channeling and Coding Techniques for Information Services Transmitted through Systems Radio Communication System Incorporated The foregoing provides a brief overview of portions of an air array that can be adapted to provide a broadcast information service (i.e., point to multiple dots) to subscriber users by radio signal transmissions in the Of course the suscpptor user will also need network equipment to make these transmissions and terminal equipment with which to receive this information. Such equipment, for example, can include conventional cellular equipment. For example, Figure 4 is a block diagram of a system of example cellular mobile radiotelephone, which includes a station 1 Example base 10 and mobile station 120 The base station includes a control and processing unit 130 which is connected to the MSC 140 which in turn is connected to the PSTN (not shown) The general aspects of said cellular radio telephone systems are known in the art, as described by US Pat. No. 5 175,867 to Wejke v. col., entitled "Neighbor Aided Passage in a Cellular Communication System", and U.S. Patent Application No. 07 / 967,027, entitled "Multimode Signal Processing," which was filed on October 27, 1992, both of which are incorporated in this application by reference The base station 110 handles a plurality of voice channels through a voice channel transceiver 150, which is controlled by the control unit V processing 130 Likewise, each base station includes a control channel transceiver 160, which may be capable of handling more than one control channel Control channel transceiver 160 is controlled by the control and processing unit 130 Control channel transceiver 160 broadcasts control information to through the control channel of the base station or cell to mobiles subject to that control channel It will be understood that the transceivers 150 and 160 can be implemented as a single device, such as voice and control transceiver 70, for use with DCCHs and DTCs that share the same radio carrier frequency The user may receive information from the broadcasting service that it describes using a conventional mobile station 120 Mobile station 120 receives the information broadcast on a channel of control in your transceiver 170 of voice channel and control Then, the > processing unit 175 evaluates the received control channel information, which includes the characteristics of cells that are candidates for attachment to the mobile station, and determines in which cell the mobile must be held Mobile station 120 also includes memory 180 as well as a device 185 input, such as a numeric board, that allows a user to interact with the mobile station A display device 190, such as an LCD system, provides a visual display of information to the user. Although the present invention is certainly applicable to conventional remote terminals such as the mobile station 120, it is also applicable to other types of information. remote receiving devices For example while the present invention is applicable to systems where the remote devices have both reception and transmission capabilities, it is also applicable to 2nd systems that have only receivers and gr devices, such as traditional remote caller devices In fact, there may be a substantial incentive to provide at least some remote receiving devices only when it is "considered that (1) the reception of the type of information - 1' for those who want diffusion services, v.gr. , sports markers, repetitions of material, etc. , in themselves they do not require transmission capacity in a remote device and (2) the remote devices can be made smaller and less expensive, excluding the transmission capacity. In any case, knowledge of the capabilities of the remote device (or lack thereof) to be supported can be useful in determining what type of Access Control Service Dispatch scheme (B-SAC) to implement. For example, in some of the following exemplary B-SAC embodiments, it may be desirable for a subscriber to acknowledge access control information, eg, an encryption key, 5 thus requiring transmission capability. . In addition to transmission capacity, the I / O interfaces associated with remote devices can also differ significantly. For example, a remote device intended to operate in conjunction or with a repeating service of broadcast material may not need an elaborate board. In this way, the dialing board as found in a regular voice telephone may not be sustained and the remote device may not have the means to input general data to the device. Instead, they can only a few "soft keys" are required for the user to search and select files. Consequently, remote devices that can be used in conjunction with broadcast information services can usually be placed in categories in the following table in terms of presence or absence of transmission capacity (TX) and local data entry capacity (LDE). ). When appropriate, it »Provide comments regarding the category of 0 remote device that is supported by (or preferably used in conjunction with) a particular B-SAC modality.

Device Capabilities 5 Capabilities TX Capabilities without TX LDE type A type Bl > Without LDE type A2 type B2 For example, the transfer of data that involves teleservices (as opposed to voice) between the network 2o and the remote device typically requires a reconnaissance signal in return from the remote device, and occasionally, additional recognition to a dedicated teleservice server. In this way, for Type B devices, basing B-SAC in a implementation similar to teleservice, where the Access control requires some reaction from the remote device, it is not feasible Even when teleservice protocols are related to allow operation without recognition signals, the system will still have to handle the dispatch to ensure that the remote device actually receives the control information Access that has been sent to it, v gr, repeatedly retransmitting this information This problem is further accentuated by the fact that Type B devices can not perform conventional registration processes, ie, it is more difficult for the system to know the location of the remote device and, therefore, the system would probably need to transmit the information to a greater number of different transmitting stations than if the general position of the remote device were known Given these general considerations of different types of remote devices, some or all can be used for reci bir diffusion user information v gr, material repetition information through subchannels of S-BCCH, various B-SAC example embodiments will now be described in accordance with a first example embodiment of B-SCA, which provides a relatively low level of access control, but it is applicable to both types A and B of remote devices, access control is provided through a variable state monitored by the remote device More specifically, the remote device maintains a variable state associated with each broadcast service, whose variable is enabled or disabled depending on whether the device remote has subscribed to the associated broadcast service If the variable state is enabled, then the remote device will present or otherwise give output to the information associated with this broadcast service, that is, repeats of material If the state variable is incapacitated then the remote device will not output the information associated with this service, even though the remote device may be able to read the information, that is, the information may be unenclosed in this example mode. The variable state can be kept in memory 180 of the remote device The memory 180 may comprise a register or register Those that use portions of a non-volatile memory or may comprise a removable smart card associated with the remote device In any case, the variable state may be enabled or disabled by receipt of special messages transmitted through the air interface A However, the diffusion service itself, the message of training / special incapacitation is directed, that is, it is device-specific, so that individual remote devices can be trained or easily incapacitated. example, remote devices can be manufactured or sold in a way where one or more state variables are previously set to "enable" over a period of time, eg, one month, 0 to allow the new device user remote a free trial period for certain services The trained state of the state variable can remain trained only for a predetermined period of time after a training message, eg, each receipt of a state variable training signal can readjust one > date that will be the date of receipt of the training signal. This date can be compared to a current date, eg. , as it is received in the channel -2 control or is followed by the internal clock of the remote device. As long as the current date is within some predetermined period of time (told j of receipt of the training message, the trained state is maintained and the remote device will output the broadcast of information in conjunction with this service. This In this way, these training messages can be considered to be similar to "beats" in the sense that they breathe life into the suscpptor's ability to continue receiving information from the broadcasting service. When a subscriber ends his subscription, the system can send signals of Capabilities addressed to the subscriber's remote device This will reset the state variable to a disabled value, in view of which the remote device will not output data associated with this service. Of course, if a subscriber becomes aware of the fact that the state variable is changed from trained to incapacitated by the reception of the training signal, you may decide to try to eliminate this process by interrupting your equipment during periods when a disabling signal is expected to be sent through the system, v gr, after the subscription is terminated The effectiveness of this type of activity can be reduced by employing a period of validation in conjunction with the training signal This exemplary use of a state variable in a B-SAC technique in accordance with the present invention can be more easily understood by reference to the following example in conjunction with Figure 5 - > 5 In it, a subscription is activated at time t0 and the service server starts transmitting periodically training messages, as represented in Figure 5 by the arrows pointing to the timeline. Initially, the frequency with which these training messages are > transmit can be relatively high. Even though the subscription was activated by the service operator at time t0, due to various reasons such as channel errors or the remote device being deactivated, the remote device does not receive its first training message until the time t3. In this way, the remote device can then store the > date / time of receipt of the training message in an i < 3 record associated state variable and start reading the information associated with the service that has been trained, eg, material repetition information in the S-BCCH subchannels illustrated in Figure 3. During the period of time that is active 13 ir5 subscription, the service server will periodically send training signals to readjust the date / time of receipt stored in the state variable record against which the current date plus the validation period can be compared, as described below. At some point in the future t22, the subscription is terminated. At that moment, or some time soon after, the service server will begin to send disabling messages as represented by 5 arrows pointing away from the line of error. weather. As soon as the remote device receives one > of these messages, readjust your status variable stored to disabled so that it will no longer output information associated with this service. At some point in time, the service server will stop sending disabling messages directed to this particular remote station, assuming that at least one was received, in order to conserve the use of > bandwidth. I 'Q However, suppose the user disconnects his remote device at time t20. that is, before the subscription ends at time t2 :, and before a disabling message can be received. Absent any other control mechanism of access, the user may not receive a signal of incapacitation, assuming that the system eventually \ stop sending disabling signals directed to that particular remote device. In this way, after the last disabling signal is transmitted by Q the service server, eg, the time t30 in the Figure , the user could theoretically activate his device and again be able to read the broadcast information since the state variable in his device would still be enabled. This potential disadvantage of ? this example modality is addressed by the provision for the stated period of validity In accordance with example modalities, the state variable will only retain its trained state with respect to this service until it receives a training message or until the date / time of its last training signal received at the last said exceeds. the current date / time As seen in Figure 5 told, therefore begins when the subscriber's equipment receives its last training signal (which may not be the last training signal transmitted by the system, as illustrated by the two arrows "upwards" subsequent in Figure 5 after told starts) Once t0? d ends in time t34, the state variable is readjusted to disabled since no additional training signals were received. At this time, the information of material repetition will not have output to user The parameter 0? d can be stored previously in the remote device Alternatively, it can be If it is changeable, t0? d must not be allowed to be larger than some time tmax maximum to avoid fraud To determine the bandwidth utilization associated with the access of the remote device. diffusion service In accordance with this example mode, the following example is considered. Assume 1 million users, with the service adding 50,000 new users each month and ending 50,000 subscriptions each month. This way, there would be 1 million users who need to receive a training message with a told. Suppose that t0? D is a month, and that five training messages need to be sent to each user within this time period for redundancy purposes. This requires 5 0 million messages per month = 166,000 messages per day = 7600 messages per hour = 2 messages per second. For the example IS-136 system described above and assuming approximately 100 payload bits available per slot S-BCCH (every 0.64 second), a length of 5 address of 32 bits to identify each subscriber equipment and 1 bit for the flag training/ I mcapaci tation, this results in 3 training messages per slot or approximately 4.7 messages per second. In this way, the training message / incapacitation requires approximately the capacity of half S-BCCH slot. During out-of-peak hours, one or more S-BCCH slots may be assigned for this purpose and, correspondingly, none during peak hours. If there are multiple services with multiple 5 associated state variables, only one bit per The service needs to be transmitted However, a service identifier may also have to be transmitted if a fixed map formation position in the message is not used, whose service identifier can provide a more flexible protocol. The format for the message could then be address, SV1 SV2 SV3 that uses a fixed mapping of bit position and service number or address Sil, SV1, SI2, SV2, where SI is the service identifier In addition to being feasible the bandwidth of the requestor intends that this B-SAC modality of state variable is also commercially possible given current industry practices Whereas most users are not technically proficient enough to tamper with a remote device schedule, v gr, to manually reset the state variable, it seems unlikely that this type of fraud will impact the service provider commercially. Also, given the size of the companies that manufacture these remote devices, the price subsidization associated with remote devices as an incentive to sell services and distribution channels for these devices, it seems unlikely that "black" market devices that have permanently trained state variables would be sufficiently valuable to impose problems. Even though the state variable B-SAC mode provides a beneficial balance between ease of use and access control, some service providers / system operators may desire additional access control and some level of data integrity to provide these types of broadcasting services. Therefore, in accordance with another example embodiment of the present invention, the information broadcast by a service provider can be encrypted. Remote devices can download a description (service) key that can change, eg, on a monthly basis. A special teleservice can be developed for the download or it can be an additional element in the Teleservice of Activation Through the Air (OATS) exposed in EIA / TIA IS-136. Along with the description key, a validity time can be included. Alternatively, a key index is provided. In the broadcasting information service channel itself (eg, replay of material) or in a general location in the BCCH, the current key index or validity time is provided. This allows the remote device to determine that the service key has is valid. This is important when, eg, the device has been disconnected for a long time. If he key index or validity time do not match > the data stored in the device, the user is alerted Note that the term service key as used herein does not necessarily imply strong algorithmic encryption techniques. In its simplest form, the service key may be a "PIN number" or, in this context, a Service Identification Number (SIN) This is not the same as the identi fi er Service that identifies a particular service from a service palette If there is no provision to enter the service key through some easy means for a typical user, the service key and the key index can be joined, it is say, the SIN can be sent clearly in the BCCH However, a validity period must still be provided.

I when a peak can easily read the SIN there is no easy way to give input to the device for ordinary users 20 In order to avoid service interrupted when the service key is changed, the system can issue the subsequent service key in advance v gr, a week in advance In this way, the remote device will store both the current service key and '5 the subsequent service key The mobile will change automatically service keys according to the > information found in the BCCH. If the key index is used, the mobile will first check the index before trying to read the service content. If the validity time in the form of date of use, the mobile can look for a BCCH date or if it is not present, from an internal clock. If the user trains a service broadcast and the device determines that the service key is not > valid or that the state variable is disabled (if there is no encryption as described above), the user is informed with an indication in the presentation and / or an audible alert. A simpler way to protect data dissemination by the service provider is to use a form simple to mix instead of encryption. Even though mixing may not prevent peaks from reading the information, most potential subscribers will not try to access mixed data. The benefit achieved with mixing against encryption is = 'ti that reduces the complexity of computing. For example, the data or part of the data can be altered by a semi-secret variable, eg, the key itself. A cyclic redundancy check (CRC) in the service layer can be altered (eg, EXOR 'd with 5 the key) or the calculation of the CRC can include the key besides the data. A lower layer CRC should not > used for this purpose since the remote device can not then distinguish service denial channel errors. Figure 6 illustrates signaling associated with a B-SAC based on mixing (or encryption) in accordance with this example embodiment. The first event (identified by the leftmost arrow pointing > upwards towards the timeline) is that the system adjusts the key to kn. At the time ti, while kn is still valid, the user requests the broadcast service. The service server sends, through the wireless system, the service key a number of times, eg, whose procedure is particularly desirable when remote type B devices are being supported by the system. In this example. the third case of service key kn containing message (as indicated by the smaller arrows pointing to the time line subsequent to the moment ti) is correctly received by the remote device. This starts the period of time during which the remote device can read the repeats of material from the broadcast service. At a later point in time t20, while kn is still valid, the user requests the termination of the service.

The system does not need to do anything, but instead allows the user to use the service until the service key expires. At some predetermined time, the system changes the key to kn + 1 The user can no longer "5 decode the data and the service can not be presented to the user since the broadcast information is now transmitted in an encrypted form using a key that is unknown to this remote device. Those skilled in the art will appreciate that it is possible to combine the modality training signal. described above with respect to Figure 5 with this (mixed) encryption mode and having the system send a training signal to the device with the assumption that the devices are designed to respond to the request to be disabled. In Figure 7, illustrates another example where B-SAC is done by mixing (or encryption) The difference between the example of Figure 6 and that of the Figure 7, is that the user does not request to end the 0 service in the example of Figure 7 In this case, the system sends a new service key kn + 1, preferably before the new key becomes valid. examples of transmission is provided used in order to maximize the probability of having 5 to the device receiving at least one of them Since the key has an index or validity time, > the remote device would know that these are just repeats if it receives more than one. when the validity time kn + 1 ends, the system repeats the procedure and sends the service key = kn + 2 a number of times. This continues until the user wishes to terminate the subscription and the procedure defined in Figure 6 when applicable. > In both of the example modalities Above, that is, state variable and encryption (mixed), the system must send either a training / incapacitation message or a service key to the remote device. The sending of the status variable message or the service key can be done in a point-to-point channel, or in the broadcast channel. Even though the modalities of Figures 5-7 are described in the context of unrecognized state variable or B-SAC modes of encryption (mixed), note that other than the "trigger" approach of sending multiple messages to the remote devices, the other aspects of these figures are equally applicable to the B-SAC modes according to the present invention wherein the state variable messages or encryption key messages are recognized by the 55 remote devices.

For the B-SAC modalities that use encryption, the key service can be sent in the broadcast channel itself. Preferably, the transmission of the service key must also be encrypted, since otherwise the information content of the same service can also be decoupled if a remote device can read the service key Note that the service key is the same for all users since the service is a point-to-multipoint service By encrypting transmission of the service key, the Fraudulent users can not then read the service key and use it on their devices to read information from a broadcast service. In the broadcast channel, the service key can then be delivered as a directed message (ie, the device address is present in the message), encpptado with a personal key (only) associated with the remote device For devices of type A, the Conventional cellular encryption techniques can be applied when the v gr service key is sent, sent in an OATS message, or in a special-purpose message, enclosed as any other voice or message transaction (v gr, based on the key). A for TIA standards) However, it is also possible perform the encryption of the service key using a special key (for this purpose), mentioned here as the B key For a type B device, which does not reveal any information through its transmissions, the ESN or identifier similar equipment can be used as the B key For Type A and B devices, the B key can be loaded in the manufacturing or input through the dashboard if the remote device has this capability For devices of type '10 The OATS procedure, or some similar technique, can be used to download the B key. For Type A devices, conventional MIN / IMSI identifiers can be used for the address of the B key message. For Type B devices, the address can be a device identifier (ESN) or an assigned MIN / IMSI For both type A and B remote devices a dedicated identifier, here referred to as the Diffusion Identifier Number (BIN) can be assigned to the device and used for the However, the -, ESN must not be used in both BIN and B key, since otherwise the description key is transmitted in the clear and the purpose for encryption is lost In order to save channel capacity in B-SAC modes of example where the teleservice mechanisms -, ~ c recognized are not used to deliver the key service, the service key for the next period > Subscription can be sent when there is less broadcast service data to send, typically nights and early mornings. In this way the user must have the device connected during non-peak hours to change the service key. While leaving the remote device connected during off-peak hours may be undesirable, access control > increased and the data integrity associated with -20 encryption can be seen to divert this disadvantage For example, these B-SAC encryption (mixed) modalities provide mechanisms to prevent ineligible users from accessing broadcast information even when they have the ability to 1C5 handle records and signals within their remote devices Even when a user can remove the service key from a device, the knowledge necessary to enter the service key into multiple devices in a way that would allow others not to -20 suscpptores read broadcast information is highly specialized and is not easily provided to the public If the broadcast service is disabled, v gr, by lack of appropriate description key and having a state variable set 2 to become incapacitated, the user can be informed that By dialing a special number, the service can be activated. For example, the service provider may use the following activation information, which could be sent along with the billing statement.

Service Monthly rate activate deactivate 1. Repetition of material (all materials found in the US in the $ 19 .95 * 92 * 23 * 1 * 92 * 45 * 1 currency 10 2. Currency $ 0 .95 * 92 * 23 * 2 * 92 * 45 * 2 3. Options $ 4 .95 * 92 * 23 * 3 * 92 * 45 * 3 4. Mutual funds $ 9 .95 * 92 * 23 * 4 * 92 * 45 * 4 (all funds found in the USA today) 5 '5. Sports brands $ 4.95 * 92 * 23 * 5 * 92 * 45 * 5 (all major leagues, 30 minutes delayed) This table uses, purely as an example, the digit pair 23 as a code for activation of broadcast service, 45 as a code for deactivation, and the last digit indicates the broadcast service number For remote devices of type A, the user can receive an automatic voice warning system and be requested to confirm a choice by pressing a specified key-5 entry: the B-SAC teleservice, which contains the service key and other attributes described below, is then downloaded These attributes may include a following message displayed to the user saying that the service is now trained Alternatively, a regular SMS message may be sent together with the B-SAC teleservice for indicate successful activation The user can be notified during the subscription time If the user selects more than > a single minimum period of time, can be downloaded Multiple service keys and associated attributes Since there are multiple services that can subscribe on an individual basis, each service has its own key and its own service status variable When a signal is sent activation, you can include the following attributes service identifier, key, key index period of validity, text description changes to the service (planned or recent changes) v gr, additions of new types of securities, greeting text , number - > phone number if there is a problem when receiving the service, etc. The system can request to remove the key to tm from verifying the contents of the mobile phone In order to avoid false base stations that try for the mobile keys, only the key index or the date validity is enough to convey this too > can be used for maintenance, that is, using the form of communication from LDE However, there are no other mechanisms to protect against audible base stations, v gr, using strong encryption in the communication channel or specifically for the teleservice B-SAC When deactivation is requested the operator > you can just skip sending the next key of 0 description or if the state control technique is used send it immediately and the deactivation signal to put the disabled state If the user disconnects the phone, in an effort to avoid receiving the deactivation signal, the system can automatically send this message again when, for example, the device performs a registration (assuming a regular mobile, ie a remote type A device) For a remote type A2 device the service key, etc., can be entered locally. This can be -20 considered valuable when testing or performing device maintenance. For example. Consider that the user has a complaint regarding the operation of their current device and receives a new device while the original device is sent to -25 maintenance The user still wants to continue ^ receiving information dissemination for its subscribed services A key to (for regular authentication) can be entered through the keyboard The service description keys, however, should not be entered directly but rather a highly secure form of encryption or other Special equipment must be used Otherwise, someone could publish the description key on the WEB and any user could enter the key to the key. security to access protected program areas on mobile phones and are currently in use Other optional features associated with B-SAC can also be implemented The user can adjust the remote device to receive a sub-game of services subscribed to, for example, use the board > The user, for example, entering a special mode, can obtain information about remaining subscription time. This may be of special interest. for pay-per-view or pre-paid subscription type that has now become a popular method for acquiring users with questionable credit. On activation, the user may have accepted a one-time charge for a limited time of access from service The user may have subscribed to multiple time segments and therefore may have downloaded the keys several times for a particular service. The user may have provided a credit card number when the activation request was generated. For smart card applications, pre-paid service credentials can be stored on the smart card. A set of keys with attributes, potentially for multiple time segments, may have been programmed in the -10 card when the card was manufactured. In this case, the description key is provided on the card and can be sent to the device for description on the device or the data subject for description can be sent first to the card for description and then ^ 5 sent back to the device for presentation, In summary, to accommodate devices of type I B, in particular type B2, the modality described above with respect to Figure 5 is appropriate when, in the broadcast channel itself, the signals in the form of ~ 2Q status variables or keys are transmitted. An advantage of the state variable solution is that the device does not need to have any other parameter known to the system other than the address. The user requesting a service can inform the operator -25 about the address of the device (eg, printed on the device) The B key, however, can not be printed on the device The service operator then establishes a relationship between an address and a B key that the manufacturing entered into the device The same procedure that has been set to transfer a A key on cell phones present before OATS makes available, between manufacturers and operators can be used For B2 devices the »B key can not be changed If the link between the address and the B key is lost, the device becomes inoperable For remote devices type Bl a new relationship can be established between an address and a B key by entering a new key Once the operator has decided whether will support Type A remote devices only Type B devices only or both devices > type A and type B, a B-SAC methodology can be developed in accordance with the principles set forth herein If an operator preaches B-SAC design in support of only type A remote devices, v gr, in the interest of maintaining the location of a remote device, then probably most B-SAC applications would include the use of a recognized delivery teleservice, v gr OATS, for send either the training / incapacitation message of state variable or the service key to the remote device. This example mode (encryption) of having some or all of the following particularities. First, transmit the broadcast service information in an encrypted form. Second, encrypt the service key / used to decipher the encrypted service information) using a conventional encryption form (eg, based on key A). Third, use a mechanism that requires recognition10 of the remote device, eg, OATS or a dedicated teleservice to deliver the fourth service key, use the MIN / IMSI standard as the address for the message that includes the encrypted service key. Other variations of these concepts also are possible. For example, the service could also transmit an indicator as to whether a B-SAC of state variable as described above with respect to Figure 5 or a B-SAC of encryption as described above with respect to the Figures is used. 6-7. -, g Remote devices could quickly check the indicator to see if they are authorized to read the information broadcast on a particular subchannel. If not authorized, the remote device could output a conventional message provided by the service provider, e.g., "dial * 888 for information additional to activate this service. "Commercials for the broadcast service in a subchannel (or other types of commercials) could also be delivered, eg, as a titular banner in the presentation of the remote device. The remote device is not authorized to read the information disseminated, eg, if the variable state is disabled and does not have the designated key, then it can be provided commercially, or alternatively, the 0 commercials can be interspersed among other broadcast information. For example, a description of the content or a subset of the broadcast service being loaded may be provided in the broadcast channel itself or as a point-to-point message. The r-5 descriptions and / or quick views of the service is a form of commercial and provides a way to attract more lenses. Several example implementations for a quick preview mode will now be described. 0 Note that more than one of these techniques can be used at the same time. First, a commercial preview can be provided in the broadcast channel without access control. Even when the subscription form of the service is controlled using a B-SAC based on encryption or mixing, a preview version is not available. A Separate identifier for the preview portion of the information broadcast in the associated channel or sub-channel with respect to B-SAC is provided, that is, indicating the service and not being. use encryption for the preview portion. The value for the identifier for the preview may be different than for free services in general. In this way, the user and / or mobile can recognize that this is a preview of broadcast information content otherwise charged. Similar preview mechanisms can be provided that have access control using a state variable based on B-SAC. An identifier can be set to a value that indicates a free sub-game of the otherwise loaded service. A second example of B-SAC control for the loaded service is provided, that is, stable to the state variable for training. > As an example, the preview content may include most shares / withholding funds, most active stocks / funds, etc., instead of a full 0 game available in the loaded portion of the channel. As a second variation, the full broadcast service may be made not subject to B-SAC for a limited time. For example, once a month the full service can be free of charge. If used - 5 B-SAC based on encryption or mixed, the encryption of incapacitate The value of the control identifier of > B-SAC may be different from the general free service. In this way, the user and / or mobile can recognize that this is a free service temporarily than would otherwise be content loaded. A similar provision can be made for state variable based in B-SAC An identifier can be set to a value indicating a free service > As a third variation, you can provide a message, v gr, using a broadcast channel or a point-to-point channel indicating a description but without a real sample of the broadcast information service. For example, for a security service, it may manifest that the user will be provided with information regarding all the actions and mutual funds found in E U A in the I currently or in the Wall Street Journal or any other scope that the user can understand For a sporting results channel the scope listed may be that league markers are provided, v gr, NHL, NBA, etc. The user can input a command and the remote device will display both the available broadcast services and an indication as to which ~ 2 of these services is eligible the user to receive (or alternatively the remote device can simply present only those services to the user that is eligible to receive) A particular service may be available for a fee by an operator but available free by another operator The user may select a service displayed from the menu for more information. The remote device presents a description of the broadcasting service to the users. The information regarding the previous warning contained temporarily free, as well as a description of the content of the preview can be provided to the remote device or the user by means of, for example (1 ) including a commercial in the billing statement, v gr that there is a preview channel when the full channel is free and where and as [V gr what keyboard inputs use j to find the description channel preview channel and the Free channel (?) Send the information to the user who uses the system in wired, v gr an SMS message or a fax, (3) indicate, for example, in the raster site of the service operator a simulated version (v gr no current data) of the broadcast channel information or a replica of what is currently being transmitted on the wireless channel (with a potential delay between the two transmission media given the implementation and protocol restrictions) User content 5 that is updated to provide a realistic view of what it would look like the service if subscribed as a device between the wireless service and the user's equipment An alternative to the provision of an identifier that indicates an advance is to send the encryption key to all the mobile phones or mobile phones selected by the system or the service operator to obtain the progress The advance and the rest of the channel are connected with different keys The disadvantages ~ associated with this implementation include that the regular clients must have two service keys or that the content of the advance must be repeated within the regular service, fast view customers should receive an encryption key, which increases the demand a -20 distribution keys This same technique (and resulting disadvantages) apply to broadcast services that use the state variable based on B-SAC mechanism and for the free channel (as opposed to the advance) 25 A particular broadcast service It can deliver and / or sell with different attributes in order to »To do especially the service to diverse interests of the market, For example, a service of repetition of material can be delivered in real time or delayed. Since it takes some time to deliver a service through a wireless interface, a "real time" broadcast information service is denoted here as a Near Real Time (NRT) service. > say, in the service server the information is 0 real time but due to the delivery time, including channel errors, it may take some additional time to deliver the information to the end user, and therefore, it can not be offered as a service. real time . Alternatively, for a lower charge the user can subscribe to a delayed service. Two logical subchannels (or logical subchannel sets) may be distributed for the dual purposes of NRT service and delayed service associated with the immism broadcast information. State variables are used for each one separate or description keys. However, this parallel service transmission would increase the bandwidth requirement to be the sum of both the fast and the slow service. Another solution, more efficient, is only to transmit the NRT service. 25 If the B-SAC methodology implemented for ^ these broadcast services are based on the concept of state variable, each service level has its own service indicator (SI) One of the Sis allows the remote device to present the data as 5 arrives on the device without any restrictions, that is to say to provide NRT service The second SI involves, by designing the device, delaying the ^ presentation of information disseminated by a certain amount of time, that is, provide delayed service Both Sis are sent in the BCCH Alternatively, a common SI is used and an additional identifier, sent to the device when the SV is updated, is used to indicate delayed presentation The required delay can be sent together -15 with the service itself, v gr, in the BCCH Alternatively, the delay can be entered through manufacturing or sent as a point-to-point message through the wireless link If the implemented B-SAC methodology is based In the concept of encryption, both levels of service read on the same date and therefore use a common key. In the key delivery, an additional identifier is sent to the device informing if the remote device will impose a delay or not before to present the data An alternative solution, which protects more strongly the service of fraudulent use, is to provide a secret variable together with the service data. The variable changes periodically for non-NRT subscribers in an unpredictable way. In this way, in addition to the basic encryption, the contents of the complete broadcast information service are mixed or encrypted with this secret variable. This secret variable can be sent in the clear or send under the protection of the basic encryption when the required delay has occurred. The non-NRT suscpptor must wait until this variable is present in the channel until it can completely describe the service data. All previously received service data since the last presence of the variable is decoded using the variable and the basic description key. The variable can be sent repetitively around the time when the stipulated delay has occurred in order to be less sensitive to channel errors. The remote NRT subscription devices will receive information sent along with the key delivery so that it can decode the data without any delay. For example, a nonlinear shift register that outputs the secret variable can be used. The content of this displacement record for a given tic time (where tic is increased with respect to to delay) is known by the device, which can in this way calculate the current value of the secret variable and decode the service data as t.5 arrives. By making the delay not hard coded in the remote devices the operator is allowed ^ change the delay. More than two levels of delay can also be used since the delay can be -20 device-specific or multiple delays can be transmitted in the BCCH. The delayed delivery aspect is applicable to any of the broadcast service information that may be variable in time / cost, eg, sports results. - 5 The organization of the services can be such that the NRT provides only a summary of the information provided in the delayed service, v.gr .. market indexes, most heavily traded shares, most commonly withheld shares, etc. This summary 20 may or may not be provided by the delayed service as well, that is, the summary must be a subset of the delayed service. This organization may be of interest if the full scope of the service requires more than a feasible amount of bandwidth to transmit in NRT, that is, since the more fast is the information associated with a service that is going to be delivered, the cycle time is shorter and the bandwidth requirement is higher. If it is not feasible to provide all the broadcast information for a particular service in NRT mode, organizing the services as a summary in NRT mode and a more complete version in delayed mode still provides a way by which the service provider can offer multiple levels of service. In this way, the -ro user can only subscribe to the NRT summary service, just the most complete delayed service or both. Again, the appropriate number of keys or SI / SV are delivered to remote subscriber devices. 5 In addition to delineating different levels of service, remote devices can operate to read broadcast information services in a manner that is intended to reduce the power consumption of those devices. In this way, a remote device 0 may not always read the broadcast service information to which that remote device has access in view of having a valid key or having a qualified state variable. For example, the user can set their remote device to read a particular service 5 subscribed only once per hour or once every ten minutes. For broadcast services having different service levels or different parts (eg, the different sub-channels of the security repeat service described above), the reading frequency of the remote device may be varied by the level of service or part thereof. of service. The sample service parts also include indexes of ^ actions or securities that are part of a particular portfolio. In addition, the reading can be triggered by smarter mechanisms than simply predetermined time intervals. Using the more complete summary and delayed service NRT example described above, the user could adjust their remote device to read the NRT summary each cycle or periodically. v.gr., every ten minutes. Then, if the information associated with a particular security / index of interest > was read in the NRT summary, the remote device could be adjusted by the user to read the delayed, more complete version of the service. Alternatively, instead of automatically reading the most complete delayed version of the service, recognition of a preset user trigger condition has occurred could result in the remote device outputting a question to the user as to whether the version should be read delayed, more complete service. The user can ask the remote device to read, v gr, a cycle of the desired information This request can be limited to a subset of a cycle based on, for example, a predetermined amount of reading time, an effort to read a complete cycle, but if they occur bit errors limited to a predetermined amount of reading time, a minimum percentage of information in a complete cycle, etc. When information is available, the user is alerted or an icon is presented on the screen of the remote device Of course, simply because the remote device has acquired new information from a broadcast information service, the immediate presentation to the user can not be justified. Consequently, the remote device may have several options for presenting information that are selectable by the user. In one mode, The information can be presented automatically as it is acquired In another way, when you acquire new in training, the device can provide an audible or visual indicator, v gr, an icon, which requires some additional input from the user before outputting the newly acquired information As mentioned in the above-incorporated US Patent Application, entitled "Channeling Y Coding Techniques for Information Services Transmitted through Radiocommunication Systems ", the information provided by the broadcast information services can be transmitted by the system using diffusion resources (ie, point to multiple points) and / or resources of no broadcast (ie, point-to-point that includes package data) For example, consider the scenario where a mobile has received, through the download of this information from a server • 10 accessible via the Internet, an association between a company name and an action symbol (or just a number), that is, the type of information found in the Security Name sub-channel in the example mode of the Figure 3. through a directed message.

Then, the system can only broadcast the start value sub-channel and the delta sub-channel. Alternatively, the information found in the home value subchannel can also be provided to remote devices using targeted messages. 20 Even all three subchannels can be provided as directed messages. For example, once a remote device has downloaded the information associated with the security name and the start value subchannels, you can request through of the delta channel information, eg, for symbols or numbers of specific actions. However, another alternative is to allow the user to define a portfolio with a service server. Then, a request initiated by a remote device can simply ask for information about the entire portfolio. Upon receiving this request, the service server can provide this information through a teleservice including the information associated with both the start and delta value channels or only the delta channel. Another possibility is a previously defined trigger could result in the downloading of this information. Although the present invention has been described with respect to a security replay service, one skilled in the art will appreciate that the invention would apply equally to said other systems wherein the information is broadcast to a user. In addition, the LDE described herein may be a cable, an infrared device, a board. or a short scale wireless communication link. The LDE can communicate with a PC (the user may have obtained the description key as an email, and an application program communicates with the device) or a special programming unit owned and operated by the operator or a representative. Many variations and combinations of the techniques taught above can be designed by a person skilled in the art without abandoning the spirit or scope of the invention as described by the following claims. -10 1

Claims (9)

1. A method for controlling access to a broadcast information service in a radio communication system, comprising the steps of: encrypting information associated with the broadcast information service; spread. by the system, the information encrypted through an air interface, wherein the encrypted information is available to a plurality of remote units; transmitting, through the system, a service key usable to describe the encrypted information as part of the message addressed to the 5 subscribers of the plurality of remote stations; and periodically change the service key.

2. The method according to claim 1. wherein it further comprises the step of: encrypting the service key before transmission by the system,

3. The method according to claim 2, wherein the step of Encrypting the service key also includes the step of: encrypting the service key using a key technique A.

4. - The method according to claim 1, further comprising the step of: recognizing, by the subscribers of the plurality of remote stations, the reception of the service key.

5. The method according to claim 4, wherein the step of transmitting the service key also comprises the step of: using Air-to-Air Activation Teleservice to deliver the service key.

6. The method according to claim 1, wherein the step of transmitting the service key further comprises the step of. transmit the service key in a di fusion channel.

7. The method according to claim 1, wherein the step of transmitting the service key further comprises the step of: transmitting the service key in a point-to-point channel.

8. The method according to claim 1, further comprising the step of: transmitting the changed service key to the current subscribers of the plurality of remote stations a predetermined time period of anticipation of using the changed service key to encrypt the information. 9 - The method according to claim 1, wherein the step of enclosing r5 information further comprises the step of mixing the information using a predetermined variable 10 - The method according to claim 1, wherein the step of transmitting the key 0 of service further comprises the step of transmitting, with the service key, a validity time during which the service key can be used to decipher the information 11 - The method according to claim 5, wherein the step of transmitting the service key further comprises the step of transmitting, with the service key, a key index that can be used by a remote station to determine if the service key is valid 0 12 - The method according to the claim 1, wherein the step of transmitting the service key further comprises the step of providing, as the service key one of an identification number per sonal (PIN) and a 5 service identification number (SIN) 13 -. 13 - The method according to claim 8 further comprising the steps of storing in the currently subscribed of the plurality of remote stations the service key changed and the service key and using the service key changed to decipher the information in a time broadcast by the system 14 - The method according to claim 1 wherein the step of transmitting the service key further comprises the steps of repeatedly retransmitting the service key at periodic intervals 15 - A method for controlling access to a service diffusion information service in a radio communication system comprising the steps of broadcasting information associated with the diffusion information service through the system through an air interface where the information is available to a plurality of remote units transmitted by the system a training signal as part of the message addressed to subscribers of the plurality of remote stations and output in one of the plurality of remote units to the information if said one of the plurality of remote units has received a directed training signal thereof 16 - The method according to claim 15, further comprising the step of recognizing, by the subscribers of the plurality of remote stations the reception of the training signal 17 - The method according to claim 15, wherein the step of transmitting the training signal further comprises the step of transmitting the training signal in a broadcast channel 18 - The method according to claim 15 wherein the step of transmitting the training signal further comprises the step of transmitting the training signal in a point-to-point channel 19 - The method according to claim 15, wherein the step of transmitting the training signal further comprises the steps of repeatedly retransmitting the training signal at periodic intervals 20 - A mobile station comprising a receiver for rec ibir broadcast information associated with an information service of diffusion in at least one dissemination resource and to receive training and training messages associated with the broadcast information service a memory device for storing a trained / incapacitated state variable having a value that is varied based on the receipt of the training and training messages and an output device for outputting the broadcast information only when the trained / disabled state variable has a trained value 21 - The method of claim 1 wherein the remote subscriber stations incur in a rate to have access to the information enpptada 22 - The method according to claim 21 wherein the rate is deducted from one of a bank account and a previously paid account 23 - The method according to claim 21 wherein the fee is charged to a credit card account 24 - A mobile station they buy of a receiver to receive encrypted broadcast information associated with a broadcast information service on at least one broadcast resource and to receive a service key that is you can use to describe the encrypted information; a memory device for storing the service key; and an output device for outputting the information broadcast after the description of the encrypted information. by the service key. 25. The mobile system according to claim 24. wherein the service key is encrypted before transmission of the broadcast information service. 26. The mobile system according to claim 25, wherein the service key is encrypted in accordance with a key technique A. 27.- The mobile system according to claim 5, wherein the service key it is valid for a predetermined period of time 28.- The mobile system according to claim 27, wherein the receiver receives a subsequent service key before the expiration of the predetermined period of time. 2

9. A radio communication system for providing broadcast information services to subscribers of the services, the system comprising: a means of encryption to encrypt the broadcast information; a transmission means for transmitting the encrypted broadcast information and for transmitting a key that can be used to decipher the encrypted broadcast information, and at least one remote receiving means for receiving the encrypted broadcast information and for receiving the transmitted key , where the means of ^ reception also comprises a processor element to use the key to describe the information -10, and an output means for outputting the deciphered information at a predetermined time after the deciphered information is received. 30 - The radio communication system according to claim 29, wherein the - 5 information includes financial market activity 31 - The radio communication system of »According to claim 29, wherein the information includes sports markers 32 - The radio communication system of -20 according to claim 29, wherein the information includes news headlines 33 - A method to provide access to an information service of broadcasting in a radio communication system, comprising the steps of -25 encrypting associated information portions with the diffusion information service; disseminating, through the system, information associated with the broadcast information service through an air interface, where the information is available to a plurality of remote units, transmitting, through the system, a service key that can be used to describing the encrypted portions of information as part of the message addressed to the selected ones of the plurality of 10 remote stations; and periodically change the service key. 34.- The method according to claim 34. wherein the key is transmitted to the subscribers of remote stations 15 35.- The method according to claim 34, wherein the broadcast information includes commercial messages for the service of broadcast information, messages being transmitted to non-subscribers of remote stations. 'twenty 25