The present invention relates to the mobile communication field, particularly to a CRP (the Proxy for Calls to a Roaming Subscriber) and a proxy method for calls to a roaming subscriber.
Presently, with the existing routing solution for roaming mobile telephones in the mobile networks, a voice bear has to be established between the mobile network in the home region and that in the visit region to support calls of a mobile subscriber in roaming state. Since the communication route is very long and the network resources are occupied severely, the call quality of roaming service is degraded greatly; in addition, the cost of the calls in roaming state is much higher than that in a state excluding roaming. Especially, for a subscriber in international roaming state, any call to the subscriber is an international long-distance call, i.e., that call has to be accomplished through a voice bear between the mobile network in the home country and that in the visit country; therefore, the subscriber has to pay the charge for international long-distance call between the home country and the visit country, even though the calling party is within a stone throw to the roaming subscriber (e.g., a companion in the same tourist party, or a mobile subscriber or fixed subscriber in the visit country), the voice bear has to be established to the home country and then detours. The international long-distance connection results in degraded call quality; in addition, the subscriber has to pay double charge for the international long-distance calls. Though the SOR (support of optimal route) method in GSM and 3GPP provide a solution, it requires modification to a large amount of network devices as well as coordination between network devices of operators in different countries. Therefore, the method is not used substantially at present.
An object of the present invention is to provide a CRP (the Proxy for Calls to a Roaming Subscriber), through which the calls to a roaming subscriber can be accomplished.
Another object of the present invention is to provide a proxy method for calls to a roaming subscriber in a visit region using said CRP, to avoid a detour to the home region.
The CRP of the present invention comprises: a voice bear and signaling management module, a call access control module, a message processing module, and a waiting call data storage module;
Said CRP also comprises a terminal input device, which is connected with the message processing module and designed to configure the content of the callback acknowledgement message.
The method of the present invention comprises: initiating a request to the Proxy for Calls to a Roaming subscriber, CRP; said CRP informing the roaming subscriber to call back; and then accomplishing the call switching for the calling subscriber and the called subscriber.
Said proxy method for calls to a roaming subscriber further comprises the following steps:
The proxy service request for calls to the roaming subscriber in step a may be accomplished by initiating a call request from the calling subscriber directly.
The call may be accomplished by dialing “the special service number of the CRP+the called number”.
If the called subscriber is an international roaming subscriber, a prefix of international dialing number and the home country code in which the called subscriber is registered need to be dialed before the called number.
The proxy service request for calls to the roaming subscriber in step a may be accomplished by sending a call subscription message.
Said sending the call subscription message is accomplished by Unstructured Supplementary Service Data, USSD.
Said sending the call subscription message is accomplished by short message.
The callback request message in step b comprises an indication, which indicates the way in which the called subscriber dials the calling subscriber.
In said proxy method for calls to a roaming subscriber, the callback number used by the called subscriber, after he/she receives the callback request message is the special service number of said CRP.
In said proxy method for calls to a roaming subscriber, the callback number used by the called subscriber, after he/she receives the callback request message is the special service number of said CRP+a number instructed by the system.
Said number instructed by the system represents an identification number of the call request that is assigned by the system or other indication that can be recognized by the CRP.
In said step d, if there is no call connection from the calling subscriber to the CRP, a connection may be established through the following steps:
With above device and method, the roaming subscriber being as the called party can be avoided, unnecessary long-distance call cost for the calling and the called subscribers can be saved and the call quality for roaming subscribers can be improved.
The detailed embodiments of the present invention will be hereinafter described with reference to the attached drawings.
Said voice bear and signaling management module receives call request signaling from other network elements and sends the signaling to the call access control module, which stores the call-relevant information into the waiting call data storage module and requests the message processing module to send an acknowledgement message to the called subscriber; the message processing module then sends a callback acknowledgement message to the called subscriber, the call access control module accomplishes the call switching.
Said CRP also comprises a terminal input device, which is connected to the message processing module and designed to configure the content of the callback acknowledgement message.
The proxy method for calls to a roaming subscriber according to the present invention comprises: initiating a request to the CRP, which requests the roaming subscriber to call back to it, and switches the call for the calling subscriber and the called subscriber, so that both the calling and the called subscriber are both calling parties when viewed from the CRP; thus the roaming subscriber being as the called party is avoided.
Suppose a subscriber B roams into a region where a subscriber A is registered in, and the subscriber A wants to call the subscriber B, the call process will comprises the following steps with the proxy method for calls to a roaming subscriber according to the present invention:
In step b, the callback request message contains the indication which indicates the way in which the called subscriber dialed the calling subscriber.
The indication may be one of the following cases as determined by CRP:
In above step d, if there is no call connection between the calling subscriber and the CRP, a connection may be established through the following steps:
In this embodiment, the subscriber A may initiate the request by call (i.e., dialing the special service number of CRP+the called number). If the called subscriber is an international roaming subscriber, a prefix of international dialing number and the home country code in which the called subscriber is registered need to be dialed before the called number.
As shown in
The relevant data in the waiting call data storage module will be cleared up after the call is switched successfully or switching timeout.
The present accomplish call access to the roaming subscriber by introducing a CRP in the traditional mobile communication systems. It provides a device and a method that can avoid detour to the home region while having no special requirement for the traditional network devices, so as to improve call quality of the roaming subscriber and save unnecessary long-distance call cost for the calling subscriber and the called subscriber.
Though the present invention is described with above preferred embodiments, it is understood the protection scope of the present invention is not defined by the embodiments. Those skilled in the art may easily make modifications or replacements within the disclosure of the present invention; however, any such modification or replacement shall be deemed as falling into the protection scope of the present invention. Therefore, the protection scope is only defined by the claims.
Number | Date | Country | Kind |
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02129228.0 | Sep 2002 | CN | national |
PCT/CN03/00772 | Sep 2003 | WO | international |