Method for preventing delivery of call to mobile unit and method for ristricting call terminations and mobile switching center

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to wireless communication systems, and particularly relates to methods and devices for limiting incoming calls when the mobile unit is roaming.

【0002】

[Conventional technology]

In current wireless communication systems, a location request message typically arrives at a mobile unit via the mobile switching center's roamer access port (MSC), which is the home system of the mobile unit. Sent to MSC. This requires that intersystem messages be exchanged when the home system determines that calls to its mobile unit over the Roman access port are not allowed.

【0003】

For example, if the visited system prohibits incoming calls to a particular mobile unit registered, the location request message will still be initiated for the home system. As a result, network and system resources are unnecessarily used even if the home system a priori decides that incoming calls to the mobile unit are not allowed. If a wireless intelligent network (WIN) service application such as prepaid is not part of a call (eg, RAN call), there is potential for uncertain or optimal service.

【0004】

FIG. 1 shows a ladder diagram 100 of a call flow for denying access to a conventional roaming mobile unit. This method of roaming mobile unit call restriction is performed by sending a message from the serving MSC to the HLR and requesting the status of the incoming restriction code field. This mechanism requires an extra SS7 message to be issued for every switch-based RAN call. As a result, prior art methods require additional messages to be sent, which can delay the initiation of calls to roaming mobile units and consume additional system resources.

【0005】

Conventional communication systems include an originating system (home) MSC, a home location register (HLR), a visitor location register (VLR), a serving (visited) MSC, and a mobile unit. The mobile unit preferably joins the originating MSC as its home system, and the subscriber record is thereby included in the HLR. In the call flow of FIG. 1, the determination of the incoming access code parameter does not occur until a call request for the mobile unit on the RAN port arrives. Therefore, the serving MSC must send a location request message asking for the status of the incoming access code parameter each time a Roman port call occurs.

【0006】

When moving out of the coverage area of the originating MSC, the mobile unit is considered roaming. The mobile unit can then communicate with the serving MSC, which will generate a user record associated with the mobile unit and store the user record in the VLR.

【0007】

By entering and registering in the service area covered by the serving MSC, the VLR sends a registration notification message (REGNOT) 101 to the HLR. The registration notification message 101 includes the identification number of the mobile unit and other parameters.

【0008】

The HLR looks up the subscriber record of the mobile unit and sends the registration notification response message 103 back to the VLR. In the prior art, the incoming call restriction code parameter is set by default to allow Roman access number (RAN) calls to the mobile unit. This can be done by setting the value of the incoming call restriction code parameter to a value of "unrestricted". The unrestricted value is the default, so at this point calls to the mobile unit through the RAN port of the serving MSC are allowed without further confirmation.

【0009】

Now the RAN call request 105 arrives at the serving MSC for the mobile unit. The serving MSC must determine whether the mobile unit is allowed to receive RAN calls by its originating MSC. In the prior art, this is done when a call request is received. Also, in the prior art, this is done each time a call request is received for a mobile unit that uses the RAN port. The serving MSC must send another message, location request message 107, to the HLR.

【0010】

The location request message 107 typically contains a request for the value of the incoming restriction code parameter stored in the TerminationAccessType field, among other fields. If the incoming restriction code parameter field is sent to reject a (RAN) call to the mobile unit, the RAN call request 206 is rejected and the mobile is rejected, as shown in Figure 1 by the value "TerminationsDenied". Not sent to the unit. If the incoming restriction code parameter was sent to the mobile unit to reject the (RAN) call, the RAN call 105 was sent to the mobile unit, preferably by having a value other than "TerminationsDenied". It will be.

【0011】

[Problems to be Solved by the Invention]

Therefore, there is a need for methods and devices for limiting incoming calls when the mobile unit roams. There is also a need for methods and devices to minimize the number of messages that pass through the communication system while eliminating fraudulent opportunities and limiting incoming calls that use less system resources.

【0012】

[Means for solving problems]

One object of the present invention is to provide methods and devices for limiting incoming calls to roaming mobile units. As used herein, the term "termination" refers to the reception of a call request by a target subscriber or the completion of a call to a target subscriber. The term "roaming" refers to a mobile using or requesting a Cellular Metwork service other than the mobile's home network.

【0013】

Roaming typically requires the mobile unit to communicate with its non-home MSC mobile exchange center (MSC). However, it is also intended that the mobile unit can roam within its home system. In such a case, the mobile unit will be connected to the home MSC by the RAN number associated with the home MSC. In this way, the mobile unit can be prevented from using services that the home MSC wants to prevent from being used by the mobile unit from other systems, such as prepaid services.

【0014】

The present invention provides a method that allows a home system to automatically block roamer port calls to a particular mobile unit. This is preferably done by adding a new value for the incoming call restriction code parameter.

【0015】

The present invention provides a method that allows a serving system to deny access to a Roman access port call to a particular mobile unit.

【0016】

The present invention provides information to a serving MSC so that the serving MSC can limit incoming calls when a Roman Access Number (RAN) call is being attempted. This is preferably done without the need for subsequent messaging to determine if the mobile unit has RAN permissions.

【0017】

In a preferred embodiment of the invention, a predetermined parameter, the TerminationRestrictionCode, is used to inform the serving MSC that RAN access is denied. An additional value is assigned to this parameter, separating it from the rejected (value = 1) and unrestricted (value = 2) values. The TerminationRestrictionCode is an optional parameter sent during registration or in the mobile unit profile whenever a mobile unit profile is requested.

【0018】

By providing a simple and standard mechanism for blocking fraudulent calls, applications such as prepaid applications can proceed without sophisticated call-time workarounds for RAN restrictions. .. The present invention allows service providers to provision parameters in home location registers (HLRs) as part of a prepaid subscriber setup and eliminate the need for call-time interactions to handle calls. To do.

【0019】

The present invention provides an efficient and inexpensive solution to the problem of fraudulent calls made in prepaid cellular systems. The present invention provides methods and devices that do not allow incoming Roman port calls to roaming mobile units. The present invention eliminates the step of messaging from the serving MSC to the originating system when the originating system does not want to allow the Roman port call to be received by a particular subscriber.

【0020】

The present invention thereby reduces inter-system messages and reduces the potential for fraudulent calls to the serving system by the roaming mobile unit. The present invention also reduces network traffic in the communication system by blocking SS7 messages sent to the HLR of the originating system when a call arrives at the mobile unit via the Roman port.

【0021】

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention is better understood with reference to FIGS. 2 and 3. FIG. 2 shows a ladder diagram 200 of a call flow for denying access to a roaming mobile unit according to the present invention. The communication system includes an originating system (home) MSC, a home location register (HLR), a visitor location register (VLR), a serving (visited) MSC, and a mobile unit. The mobile unit is preferably the originating MSC as its home system and the HLR as its home registration database.

【0022】

The communication system is preferably an AMPS (Advanced Mobile Phone Service) / PCS (Personal Communications Service) wireless system, but alternatively, but not limited to, GSM (Global System for Mobile Communications) and CDMA (Code). It may be any wireless communication system including Division Multiple Access (TDMA), Time Division Multiple Access (TDMA), cdma2000, W-CDMA (Wideband CDMA) and UWC-136, and wideband TDMA technology.

【0023】

When traveling outside the coverage area of the originating MSC, the mobile unit is considered roaming. The mobile unit can then communicate with a serving MSC that generates a user record associated with the mobile unit and stores the user record in the VLR.

【0024】

The call flow for a mobile unit scenario that roams to a serving MSC and at the same time receives a call through the RAN port is as follows. By entering and registering in the service area covered by the serving MSC, the VLR sends a registration notification message (REGNOT) 202 to the HLR. The registration notification message 202 includes the identification number of the mobile unit and other parameters.

【0025】

The HLR looks up the subscriber record of the mobile unit and sends the registration notification response message 204 back to the VLR. Using the present invention, an incoming call restriction code parameter is set to reject a Roman access number (RAN) call to a mobile unit. In a preferred embodiment, the incoming restriction code parameter is a TerminationRestrictionCode field set to the value RANAccessDenied indicating that the mobile unit cannot receive RAN calls while roaming. The VLR stores the subscriber record for the mobile unit that contains the TerminationRestrictionCode field.

【0026】

The RAN call request 206 now arrives at the serving MSC for the mobile unit. Based on the registration of the mobile unit, the communication system knows that the mobile unit is located within the coverage area of the serving MSC. The serving MSC receives a RAN call request 206 directed to its mobile unit. The serving MSC searches the subscriber record associated with the mobile unit and searches the subscriber record for the value of the incoming restriction code parameter.

【0027】

If the incoming restriction code parameter field is set to reject (RAN) calls to the mobile unit, the RAN call request 206 is rejected and the RAN call request 206 is not sent to the mobile unit. If the incoming restriction code parameter, preferably the TerminationRestrictionCode, is not set to reject (RAN) calls to the mobile unit, preferably by being set to a value other than RANAccessDenied, the RAN request 206 moves. It will be sent to the body unit.

【0028】

Therefore, a preferred embodiment of the present invention provides faster access times for RAN calls for roaming mobile units. The invention also allows less system resources to be used and minimizes the potential for fraud in roaming mobile units, such as prepaid applications.

【0029】

FIG. 3 shows a flowchart 300 of a method for limiting incoming calls to a roaming mobile unit according to the present invention. In this embodiment, the mobile unit roams from its home coverage area supported by its originating (home) MSC to a roaming area supported by its serving MSC. In this embodiment, the roaming mobile unit is accessing the serving MSC through the Roman port and will send a request for the call to the serving MSC.

【0030】

The serving MSC receives a call request from the roaming mobile unit (301). The call request can be for a prepaid call.

【0031】

The serving MSC determines if the call request was received on the Roman port (303). If so, this indicates that the mobile unit receiving the request does not consider the serving MSC to be its home MSC. The serving MSC must then determine whether the mobile unit receiving the call request can receive such a call request.

【0032】

If the call request is not received on the Roman port, the serving MSC performs typical call processing for the call request (304). This may include processing the call and allowing the mobile unit to receive or connect the call. This can include rejecting the call request for a variety of reasons. Then, the process ends (399).

【0033】

If the call is received by the serving MSC at the Roman port as determined in step 303, the serving MSC determines if the roaming mobile unit has a service profile stored in the serving MSC (305). .. The service profile is preferably received by the serving MSC from the VLR when the roaming mobile unit enters the service area covered by the serving MSC. The service profile includes, among other things, the incoming call restriction code. The incoming call restriction code is a field indicating whether or not the mobile unit associated with the incoming call restriction code can receive a call in the visited MSC.

【0034】

If the mobile unit does not have the service profile present in the serving MSC determined in step 305, the serving MSC performs the initiating qualification function (306). This involves requesting and receiving a service profile for the roaming mobile unit from the HLR. The service profile preferably includes an incoming call restriction code for the mobile unit. Then the process ends (399).

【0035】

If the service profile of the mobile unit exists in the serving MSC determined in step 305, the serving MSC searches for the incoming restriction code of the mobile unit (307). The incoming call restriction code preferably contains 1 byte or octet information. In a preferred embodiment, a value of 1 indicates that the incoming call is denied, a value of 2 indicates an unrestricted value, and a value of 4 indicates that Roman port access is denied. It should be understood that different values can be chosen and can be used to represent the same information.

【0036】

The serving MSC then determines whether the incoming restriction code is set to allow Roman port access calls (309). If the value is set to an unrestricted value (a value of 2 in the preferred embodiment), the mobile unit is allowed to receive a Roman port call. If the mobile unit is not allowed to receive the Roman port call determined in step 309, the serving MSC rejects the call request received from the mobile unit (310).

【0037】

The mobile unit will not be able to receive Roman port calls if the incoming call restriction code is set to either the incoming call rejection value or the Roman port access blocking value. In a preferred embodiment, the incoming call rejection value is "1" and the Roman port access rejection value is "4". However, other expressions may be used to represent these values. Then the process ends (399).

【0038】

If the mobile unit is allowed to receive the Roman port call determined in step 309, the serving MSC receives the call request received from the mobile unit (311). In this manner, if the mobile unit indicates that it is preferably allowed to receive a Roman port call request before the serving MSC receives the call request, the Roman call to the roaming mobile unit will be. Incoming call, i.e. connected. The process of determining whether a mobile unit can receive a Roman port call ends (399).

【0039】

The present invention provides methods and devices for solving problems associated with prior art. The present invention provides methods and devices for limiting incoming calls when the mobile unit is roaming. By storing the incoming call restriction code in the serving MSC, this value check does not have to be done each time a call request enters the roaming mobile unit. In this way, messaging is done more efficiently in the communication system.

【0040】

The present invention makes it easier to embody techniques for limiting RAN access in support of prepaid deployments. The present invention is less bandwidth intensive than the current illegality used to solve the RAN fraud problem.

【0041】

[Effect of the invention]

As described above, according to the present invention, it is possible to provide a method and a device for limiting incoming calls when the mobile unit roams.

【0042】

The number in parentheses after the requirements of the invention in the claims indicates the correspondence of one embodiment of the present invention and should not be construed as limiting the scope of the invention. ..

[Simple explanation of drawings]

[Figure 1]

A ladder diagram showing a call flow for denying access to a roaming mobile unit according to the present invention.

[Figure 2]

A ladder diagram showing a call flow for denying access to a roaming mobile unit according to the present invention.

[Fig. 3]

The flowchart which shows the method for limiting the incoming call to the roaming mobile unit by this invention.

[Explanation of symbols]

101 Registration Notice 103 Registration notification response 105 RAN call to mobile unit 107 Location Request (= Rome Port Access ...) 109 Location Request Response 202 Registration Notice 204 Registration notification response 206 RAN call to mobile unit