WO2008145610A2

WO2008145610A2 - Method, system and server for domain selection in communication system

Info

Publication number: WO2008145610A2
Application number: PCT/EP2008/056362
Authority: WO
Inventors: Li Zhu
Original assignee: Nokia Siemens Networks Oy
Priority date: 2007-05-29
Filing date: 2008-05-23
Publication date: 2008-12-04
Also published as: WO2008145610A3; CN101316218A

Abstract

The present invention discloses a method for achieving a domain selection in a communication system, a system for achieving a domain selection in a communication system, and an domain selection apparatus. In the method of the present invention, a terminal side domain selection preference and a network side domain selection preference are first obtained, and then the domain selection is carried out according to the obtained terminal side and network side domain selection preferences. The system of the present invention comprises a terminal side domain selection preference storage unit, a network side domain selection preference storage unit, a domain processing unit, and a domain selection execution unit. The IMS universal domain selection server proposed in the present invention comprises a terminal side domain information exchange unit, a network side domain information exchange unit, and a domain decision-making unit. The present invention is capable of ensure that a selected domain can satisfy at the same time the service requirements both by user equipment and by a network side, so as to greatly improve the overall performance of a system.

Description

DESCRIPTION

TITLE

Method, system and server for domain selection in communication system

Technical Field

The present invention relates to network communication technology, and more particularly to a method, a system and a server for achieving domain selection in a communication system.

Background Art With the development of communication technologies, the inter-linking and inter-communication between mobile networks, fixed-line networks and Internet have become the trend of current network developments. Aiming at this development trend regarding the inter-linking and inter- communication now emerges an IP multi-media sub-system (IMS) . An IMS network is a network sub-system introduced on the basis of a grouping loading network for carrying out the IP multi-media communication control, it is capable of facing various access techniques, and of providing experiences of IP multi-media communication according to personalized user data and an access approach by shielded users to control a degree of opening in the service capability, thereby making fundamental changes to the vertical structure of one-service- one-network in conventional networks .

Since the IMS network can face various access networks, and can integrate various service domains for providing operation services, the IMS network is capable of providing a domain selection function to users, so as to enable the users to select different domains for achieving operations in the IMS network. At present, the basic process for achieving domain selection by means of the domain selection function provided by the IMS networks to users is: when implementing a voice call continuity (VCC) service in an IMS network, in order to ensure that a voice call between the calling and called users is not interfered by various factors such as the locations of the users and the transmission performance of the network, which may lead to the failure in establishing a connection or to an interruption, in the IMS network the access domain used for accessing the network can be selected by user equipment (UE) , and the service domain for providing particular services to the users is selected by the network side.

However, the method for achieving domain selection in the prior art has the following drawbacks:

1. When selecting an access domain, it is selected by the UE according to a terminal side preference , for example according to the UE' s own capability and the preferences of a user, furthermore, when the UE selects an access domain, it will not take into consideration current service demands in the network; therefore, the access domain finally selected is probably not capable of satisfying the service demands of the UE and the network side at the same time, so the performance of the system as a whole cannot be improved. For example, if a UE prefers to select the circuit switching (CS) domain as the access domain for accessing the network, but at the network side the CS domain is overloaded by the access service while the access service load of the IMS domain is relatively small, therefore, it will not meet the requirements by the network side for a load-balanced service, and as a result the performance of the system as a whole is degraded.

2. When selecting a service domain, it is carried out by the network side according to the network side preference , for example, according to the requirements of load-balanced services or the quality of service (QoS) on the network side. Moreover, when the network side selects a service domain it may not take into consideration of the current service demands by the terminal side. Therefore, the service domain finally selected is probably not capable of satisfying the service requirements by the UE and the network side as the same time, so that it is not capable of improving the performance of the system as a whole. For example, when the network side selects the circuit switching (CS) domain as the service domain for providing the service to the UE according to the load-balanced services requirements while the UE may not wish to obtain the operation service in the CS domain for considerations regarding the service costs, then the service demand by the UE side is not satisfied, and the performance of the system as a whole is degraded.

3. Currently, only practical solutions for selecting between the IMS domain and the CS domain are available, however, with the rapid development of the communication technologies, the types of access domain and service domain are not limited to the IMS domain and the CS domain, for example, currently there are also available various access domains such as the worldwide interoperable microwave access network (Wimax) , the fixed broadband accesses such as the Digital Subscriber Line Access Multiplexer (DSLAM) network, the wired television network based on IP such as the packet cable network, etc., therefore, the method for selecting domain only between the IMS domain and the CS domain realized within the capability of the prior art also reduces the flexibility of service, restricts the service developments, and degrades the operations' quality of service.

Summary of the Present Invention:

A main object of the present invention is to provide a method for achieving domain selection in a communication system, a system for achieving domain selection in a communication system, and an IMS universal domain selection server, so as to ensure that a selected domain is capable of satisfying at the same time the service requirements of the UE and the network side, and to improve the performance of the system as a whole . In order to achieve the object described above, the solution of the method according to the present invention is implemented in such a way that: a method for achieving a domain selection in a communication system, said communication system comprises a terminal side and a network side, the method comprising: obtaining a terminal side domain selection preference and a network side domain selection preference ; and carrying out the domain selection according to the obtained terminal side and network side domain selection preferences.

Preferably, the method also comprises carrying out said obtaining step by a pre-defined universal domain selection server in an IP multimedia sub-system (IMS) .

Wherein, said step for obtaining the terminal side domain selection preference by the IMS universal domain selection server comprises: transmitting by the terminal a terminal side domain selection preference previously configured therein to the IMS universal domain selection server, and obtaining by the IMS universal domain selection server the terminal side domain selection preference by receiving the same .

Wherein, said step for obtaining the network side domain selection preference by the IMS universal domain selection server comprises: transmitting by any one or more of a home location server (HSS) , an operation maintenance (O&M) system, and an IMS network application server (AS) a network side domain selection preference previously configured therein to the IMS universal domain selection server, and obtaining by the IMS universal domain selection server the network side domain selection preference by receiving the same.

Optionally, after a message for requesting a domain selection preference transmitted by the IMS universal domain selection server has been received, said step for transmitting said domain selection preference previously configured therein to the IMS universal domain selection server is carried out.

Wherein, said domain selection preference comprises an access domain selection preference; and said step for carrying out the domain selection comprises: determining by the IMS universal domain selection server an access domain corresponding to the terminal according to an obtained terminal side access domain selection preference and an obtained network side access domain selection preference , transmitting the information of the terminal' s corresponding access domain to the terminal, and selecting by the terminal the corresponding access domain according to the received access domain information.

Wherein, said domain selection preference comprises a service domain selection preference, and said step for carrying out the domain selection comprises: the IMS universal domain selection server determining a service domain corresponding to the terminal according to an obtained terminal side service domain selection preference and an obtained network side service domain selection preference; after the IMS network application server in the IMS network having received a conversation message corresponding to said terminal, updating an original terminal identification carried in the conversation message to be a previously saved terminal identification of the terminal in the determined service domain according to the determined service domain corresponding to the terminal; and the IMS network application server in the IMS network selecting the determined service domain corresponding to the terminal according to said updated terminal identification in the conversation message, and routing the conversation message to the service domain corresponding to the terminal.

Optionally, after the IMS universal domain selection server has determined the service domain corresponding to the terminal and before it carries out said updating step, it further comprises the following steps: transmitting by the IMS universal domain selection server the determined service domain information corresponding to the terminal to the IMS network application server in said IMS network; and carrying out by the IMS network application server in the IMS network said step for updating the original terminal identification carried in the conversation message to the previously saved terminal identification of the terminal in the determined service domain.

Optionally, after the IMS network application server in the IMS network has received the conversation message corresponding to the terminal and before it carries out said updating step, it further comprises: transmitting by the IMS network application server in the IMS network the received conversation message corresponding to said terminal to the IMS universal domain selection server; carrying out by the IMS universal domain selection server said step for updating the original terminal identification in the conversation message to the previously saved terminal identification of the terminal in the determined service domain; and after said updating step having been carried out, and before selecting by the IMS network application server in the IMS network the determined service domain corresponding to the terminal, it further comprises: transmitting by the IMS universal domain selection server the conversation message with the updated terminal identification to the IMS network application server in the IMS network.

Optionally, said terminal and the IMS universal domain selection server carry out said information exchange by messages of a hypertext transmission protocol (HTTP) .

Optionally, the terminal carries out said obtaining step.

Wherein, said step for obtaining the terminal side domain selection preference by the terminal comprises: obtaining by the terminal the terminal side domain selection preference according to information of a terminal side domain selection preference previously configured therein.

Wherein, said step for obtaining the network side domain selection preference by the terminal comprises: transmitting by any one or more of HSS, O&M, and an IMS network application server in an IMS network a network side domain selection preference previously configured therein to the terminal, and obtaining by the terminal the network side domain selection preference by receiving the same.

Wherein, said domain selection preference comprises an access domain selection preference, and said step for carrying out the domain selection comprises: determining by the terminal an access domain corresponding thereto according to an obtained terminal side access domain selection preference and an obtained network side access domain selection preference, and selecting the corresponding access domain.

Wherein, said domain selection preference comprises a service domain selection preference; and said step for carrying out the domain selection comprises: determining by the terminal a service domain corresponding to the terminal according to the obtained terminal side service domain selection preference and network side service domain selection preference, and transmitting the determined service domain information corresponding to the terminal to the IMS network application server in the IMS network; and after the IMS network application server having received a conversation message corresponding to the terminal, updating the original terminal identification in the conversation message to a previously saved terminal identification of the terminal in the determined service domain according to the determined service domain information corresponding to the terminal; and selecting by the IMS network application server in the IMS network a service domain corresponding to said terminal according to said updated terminal identification in the conversation message, and routing the conversation message to the service domain corresponding to the terminal.

Preferably, whenever timing has reached a preset length of time for updating, said step for obtaining the terminal side domain selection preference and the network side domain selection preference is carried out.

Preferably, when the terminal side domain selection preference and the network side domain selection preference comprise the same preference, selecting according to this same preference an access domain or an service domain satisfying the preference's requirements; when the terminal side domain selection preference and the network side domain selection preference do not have the same preference, finding out the preference with the highest priority according to preset priorities of the terminal side domain selection preference and of the network side domain selection preference, and selecting the access domain or the service domain satisfying the preference with the highest priority.

The present invention also discloses a system for achieving a domain selection in a communication system, which communication system comprises a terminal side and a network side, said system for achieving the domain selection comprising: a terminal side domain selection preference storage unit for saving a terminal side domain selection preference; a network side domain selection preference storage unit for saving a network side domain selection preference; a domain processing unit, for respectively obtaining the terminal side domain selection preference and the network side domain selection preference from the terminal side domain selection preference storage unit and the network side domain selection preference storage unit, determining a domain corresponding to the terminal according to the obtained terminal side domain selection preference and the obtained network side domain selection preference, and transmitting the determined domain information corresponding to the terminal to a domain selection execution unit; and the domain selection execution unit for carrying out a domain selection according to the domain information corresponding to the terminal.

Wherein, said terminal side domain selection preference storage unit can be provided in the terminal.

Wherein, said network side domain selection preference storage unit can be provided in any one or more of an HSS, O&M, and an IMS network application server in an IMS network.

Wherein, said domain processing unit can be provided in existing equipment or newly added equipment in the IMS network .

Wherein, said domain selection execution unit can be provided in the terminal and/or in the IMS network application server in an IMS network.

According to another aspect of the present invention, the present invention also provides an IMS universal domain selection server, comprising: a terminal side domain information exchange unit for obtaining a terminal side domain selection preference, and for transmitting the terminal side domain selection preference to a domain decision-making unit; a network side domain information exchange unit for obtaining a network side domain selection preference, and for transmitting the network side domain selection preference to the domain decision-making unit; and said domain decision-making unit for determining a domain corresponding to the terminal according to the received terminal side domain selection preference and the received network side domain selection preference. Wherein, said terminal side domain information exchange unit comprises a terminal side access domain information exchange sub-unit and a terminal side service domain information exchange sub-unit, said network side domain information exchange unit comprises a network side access domain information exchange sub-unit and a network side service domain information exchange sub-unit, and said domain decision-making unit comprises an access domain decision- making sub-unit and a service domain decision-making sub- unit, and wherein the terminal side access domain information exchange sub-unit is used for obtaining the terminal side access domain selection preference from the terminal and for transmitting the terminal side access domain selection preference to the access domain decision-making sub-unit; the network side access domain information exchange sub-unit is used for obtaining the network side access domain selection preference from any one or more of an IMS network application server, HSS and O&M in the IMS network, and for transmitting the network side access domain selection preference to the access domain decision-making sub-unit; the access domain decision-making sub-unit is used for determining an access domain corresponding to the terminal according to the received terminal side access domain selection preference and the received network side access domain selection preference; the terminal side service domain information exchange sub- unit is used for obtaining the terminal side service domain selection preference from the terminal and for transmitting the terminal side service domain selection preference to the service domain decision making sub-unit; the network side service domain information exchange sub-unit is used for obtaining the network side service domain selection preference from any one or more of the IMS network application server, HSS, and O&M in the IMS network, and for transmitting the network side service domain selection preference to the service domain decision-making sub-unit; and the service domain decision-making sub-unit is used for determining a service domain corresponding to the terminal according to the received terminal side service domain selection preference and the received network side service domain selection preference.

Preferably, said access domain decision-making sub-unit further transmits the access domain information corresponding to the terminal to the terminal side access domain information exchange sub-unit; said terminal side access domain information exchange sub- unit further transmits to the terminal the access domain information corresponding to the terminal; said service domain decision-making sub-unit further transmits the service domain information corresponding to the terminal to the terminal side service domain information exchange sub-unit; and said terminal side service domain information exchange sub- unit further transmits to the terminal the service domain information corresponding to the terminal.

Preferably, the server can further comprise a network side domain result exchange unit used for transmitting the access domain information and the service domain information corresponding to the terminal transmitted by the access domain decision-making sub-unit and the service domain decision-making sub-unit to the IMS network application server in the IMS network; wherein the access domain decision-making sub-unit is further used for transmitting the access domain information corresponding to the terminal to the network side domain result exchange unit; and the service domain decision-making sub-unit is further used for transmitting the service domain information corresponding to the terminal to the network side domain result exchange unit . Thus it can be seen that, in the present invention, whether the access domain or service domain is to be selected, it is according to both the terminal side domain selection preference and the network side domain selection preference to carry out the selection, so that it can ensure that the selected domain satisfy at the same time the service requirements of the UE and the network side, thereby it greatly improves the performance of the system as a whole.

Furthermore, whatever is the type of the access domain and service domain they all can use the solutions provided by the present invention for domain selection, therefore, the flexibility in achieving services is increased greatly, the developments of the services are facilitated and the operations' quality of service is improved.

Brief Description of the Drawings

The aforementioned and other features and advantages of the present invention will become more apparent to those skilled in the art by way of the exemplary embodiments explained below with reference to the accompany drawings, in which:

Figure 1 is a flowchart for achieving the domain selection in a first embodiment of the present invention;

Figure 2 is a flowchart for achieving the domain selection in a second embodiment of the present invention;

Figure 3 is a schematic view of a basic structure of the system proposed in the present invention for achieving domain selection;

Figure 4 is a schematic view of a preferred structure of the system proposed in the present invention for achieving domain selection;

Figure 5 is a schematic view of a basic structure of the IMS universal domain selection server proposed in the present invention; and Figure 6 is a schematic view of a preferred structure of the

IMS universal domain selection server proposed in the present invention . Detailed Description of the Preferred Embodiments

The present invention proposes a method for achieving a domain selection in a communication system. In the method, a terminal side domain selection preference and a network side domain selection preference are first obtained; and then the domain selection is carried out according to the obtained terminal side and network side domain selection preferences.

Wherein, the obtained domain selection preference can be an access domain selection preference, so the domain selection carried out can comprise the selection of an access domain; and the obtained domain selection preference can also be a service domain selection preference, so the domain selection carried out can comprise the selection of a service domain. That is to say, in the present invention, it is possible to select, according to the domain selection preferences of both the terminal side and the network side at the same time, only the access domain to be used by the terminal to access the network, or only the service domain for providing services to the terminal, and it is also possible to select at the same time the access domain to be used by the terminal to access the network and the service domain for providing services to the terminal.

In the present invention, the process for obtaining the domain selection preference and determining the result of the domain selection can be executed either by the network side or by the terminal side. Regarding each of the cases of executing by the network side and by the terminal side, the implementation of the present invention will be explained by way of a respective embodiment for each case.

Embodiment one :

In this embodiment, the process for obtaining the domain selection preference and determining the result of the domain selection are carried out by a preset IMS universal domain selection server at the network side. The term "strategy" used in some of the drawings shall be understood as "preference" used thought the description.

Fig. 1 is a flowchart for achieving the domain selection in the first embodiment of the present invention. Referring to Fig. 1, in this embodiment the process for achieving the domain selection can comprise the following steps:

Step 101: Set a terminal side domain selection preference in the terminal in advance, and set a network side domain selection preference in any one or more of a home location server (HSS) , an operation maintenance (O&M) system, and an IMS network application server (AS) .

Here, the terminal side domain selection preference set in the terminal can comprise: a terminal side access domain selection preference and/or a terminal side service domain selection preference. Furthermore, when the terminal side access domain selection preference and the terminal side service domain selection preference are set, both of them can be set in accordance with the service capability of the terminal and the preference of a user.

Moreover, the network side domain selection preference set in any one or more of the HSS, the O&M, and the IMS network application server can comprise: a network side access domain selection preference and/or a network side service domain selection preference. Furthermore, when the network side access domain selection preference and the network side service domain selection preference are set, both of them can be set in accordance with the actual service requirements of the network side, for example, the setting can be made in accordance with the requirements of balanced loads between various domains at the network side or in accordance with the requirements to the operation's quality of service (QoS) . Step 102: the IMS universal domain selection server obtains the terminal side domain selection preference from the terminal .

Here, the terminal side domain selection preference can be transmitted by the terminal in it own initiative to the IMS universal domain selection server, or the IMS universal domain selection server can also first transmit a message for requesting the domain selection preference to the terminal, and after having received the message for requesting the domain selection preference, the terminal transmits the terminal side domain selection preference to the IMS universal domain selection server; and in this way, the IMS universal domain selection server can obtain the terminal side domain selection preference by receiving the same.

During the process, the terminal can transmit the terminal side domain selection preference to the IMS universal domain selection server by means of a Hypertext Transfer Protocol (HTTP) message.

SteplO3: the IMS universal domain selection server obtains the network side domain selection preference.

Here, the network side domain selection preference can be transmitted by any one or more of the HSS, the O&M, and the

IMS network application server in their own initiative to the IMS universal domain selection server, or the IMS universal domain selection server can also first transmit a message for requesting the domain selection preference to any one or more of the HSS, the O&M, and the IMS network application server, and after having received the message for requesting the domain selection preference, any one or more of the HSS, the O&M, and the IMS network application server transmit (s) the network side domain selection preference to the IMS universal domain selection server; and in this way, the IMS universal domain selection server can obtain the domain selection preference of network side by receiving the same. SteplO4: when the domain selection preference comprises the access domain selection preference, the IMS universal domain selection server determines the access domain corresponding to the terminal according to the obtained terminal side access domain selection preference and network side access domain selection preference.

Here, for example, if the terminal side access domain selection preference obtained by the IMS universal domain selection server comprises selecting a Wimax or a CS domain as the access domain for a terminal 1, while the network side access domain selection preference obtained by the IMS universal domain selection server comprises selecting the CS domain or a DSLAM domain as the access domain for the terminal 1, then, after having taken these two preferences into consideration at the same time, the IMS universal domain selection server can decide that the CS domain is the access domain corresponding to the terminal 1.

SteplO5: the IMS universal domain selection server transmits to the terminal the access domain information corresponding to the terminal, and the terminal selects a corresponding access domain according to the received access domain information .

In this step, the IMS universal domain selection server can transmit to the terminal the access domain information corresponding to the terminal by means of a HTTP message.

After the terminal has selected a corresponding access domain, the terminal can access the corresponding access domain when it needs to access the network.

It should be noted that, the HTTP message mentioned in the description of step 102 and step 105 above can be an existing HTTP message, for example, in step 105, the access domain information corresponding to the terminal can be transmitted to the terminal by means of a HTTP 200 OK message; or the HTTP message mentioned in the description of the step 102 and step 105 above can also be another new message used in the present invention.

SteplOβ: when the domain selection preference comprises a service domain selection preference, the IMS universal domain selection server determines the service domain corresponding to the terminal according to the obtained terminal side service domain selection preference and the network side service domain selection preference.

Here, for example, if the terminal side service domain selection preference obtained by the IMS universal domain selection server comprises selecting a service domain with relatively low service fee rates as the service domain for the terminal 1, while the network side service domain selection preference obtained by the IMS universal domain selection server comprises selecting a service domain with the lowest current service load as the service domain of the terminal 1, then, after having taken these two preferences into consideration at the same time, the IMS universal domain selection server can decide that a service domain with both relatively low service fee rates and small service load as the service domain corresponding to the terminal 1.

SteplO7: after having received a conversation message corresponding to a terminal, the IMS network application server of an IMS network transmits a domain selection request that carries the information of the terminal to the IMS universal domain selection server.

SteplOδ: the IMS universal domain selection server transmits the determined service domain information corresponding to the terminal to the IMS network application server in the IMS network, according to the terminal information carried in the domain selection request. SteplO9: the IMS network application server in the IMS network updates an original terminal identification carried in the conversation message to a terminal identification of the terminal saved in advance in the determined service domain according to the determined service domain information corresponding to the terminal.

Here, because the identifications of a terminal in different service domains are different, in order to ensure that it is capable of provide service to the terminal by the service domain selected according to the service domain selection preference, then, it is necessary to ensure that the terminal identification carried in the conversation message is the identification of the terminal in the determined service domain, and for this reason, the IMS network application server in the IMS network needs to execute the process for updating terminal identification in this step. Wherein, the specific meaning of updating is that: if the identification of the terminal in the determined service domain is identified according to the received service domain information to be the same as the identification of the terminal in the service domain originally routing the conversation message, i.e. the original terminal identification carried in the conversation message, then there is no need to modify the conversation message, while if they are different, the identification of the terminal in the determined service domain is used to replace the original terminal identification carried in the conversation message.

It is to be noted that, in the process of the above step 107 to step 109, it is the IMS network application server in the IMS network that carries out the process for updating terminal identification. During the process of achieving a particular service, the process for updating terminal identification can also be carried out by the IMS universal domain selection server, correspondingly, the process of the above step 107 to step 109 can be replaced as: after having received a conversation message corresponding to a terminal, the IMS network application server of an IMS network transmits the conversation message to the IMS universal domain selection server; the IMS universal domain selection server updates an original terminal identification carried in the conversation message to a terminal identification of the terminal saved in advance in the determined service domain according to the determined service domain corresponding to the terminal, and then transmits the conversation message with the updated terminal identification to the IMS network application server in the IMS network.

Step 110: the IMS network application server in the IMS network selects the service domain corresponding to said terminal according to said updated terminal identification in the conversation message, and routes the conversation message to the service domain corresponding to the terminal.

After this, operation services can be provided to the terminal via the service domain selected by combining the terminal side service domain selection preference and the network side service domain selection preference.

Embodiment two:

In this embodiment, the process for obtaining domain selection preference and determining the result of the domain selection are carried out by the terminal.

Fig. 2 is a flowchart for achieving the domain selection in the second embodiment of the present invention. Referring to Fig. 2, in this embodiment the process for achieving the domain selection comprises particularly the following steps:

The complete descriptions for step 201 are identical to the complete descriptions for step 101.

Step 202: the terminal obtains the terminal side domain selection preference according to its own configuration. Step 203: the terminal obtains the network side domain selection preference.

Here, the network side domain selection preference can be transmitted to the terminal by any one or more of the HSS, the O&M, and the IMS network application server in their own initiative, or the terminal can also first transmit a message for requesting the domain selection preference to any one or more of the HSS, the O&M, and the IMS network application server, and after having received the message for requesting the domain selection preference, any one or more of the HSS, the O&M, and the IMS network application server then transmits the network side domain selection preference to the terminal; and in this way, the terminal can obtain the network side domain selection preference by receiving the same .

Step 204: when the domain selection preference comprises the access domain selection preference, the terminal selects the access domain corresponding to the terminal according to the obtained terminal side access domain selection preference and network side access domain selection preference.

Here, after the terminal has selected a corresponding access domain, the terminal can access the corresponding access domain when it needs to access the network.

Step 205: when the domain selection preference comprises a service domain selection preference, the terminal determines the service domain corresponding to the terminal according to the obtained terminal side service domain selection preference and the obtained network side service domain selection preference.

Step 206: the terminal transmits the service domain information corresponding to itself to the IMS network application server in the IMS network. Step 207: after having received a conversation message corresponding to the terminal, the IMS network application server in the IMS network updates an original terminal identification carried in the conversation message to a terminal identification of the terminal saved in advance in the determined service domain according to the determined service domain corresponding to the terminal.

Step 208: the IMS network application server in the IMS network selects the service domain corresponding to the terminal, and routes the conversation message with the updated terminal identification to the selected service domain corresponding to the terminal.

It is to be noted that, in the above first embodiment and the second embodiment, a user can update in real-time the terminal side domain selection preference set in the terminal, and an operator of the network side can also update in real-time the network side domain selection preference set in any one or more of the HSS, the O&M and the IMS network application server, therefore, in order to ensure that the domain selection preference on which the execution of the domain selection is base is the updated version of the domain selection preference, in the above mentioned embodiments, it is also possible to set a updating time period, so that whenever a timing reaches the length of set updating time period, the process in aforementioned example will be carried out once for obtaining the terminal side domain selection preference and the network side domain selection preference. In this way, it is ensured that the access domain and service domain are selected according to the updated domain selection preference .

It also needs mentioning that, when determining the access domain or service domain corresponding to the terminal according at the same time to both of the terminal side domain selection preference and the network side domain selection preference, terminal side domain selection preference and the network side domain selection preference are considered in a comprehensive way. For example, when the terminal side domain selection preference and the network side domain selection preference comprise the same preference, such as a preference requiring the smallest time delay, then the access domain or service domain satisfying the preference requirement can be selected according to this same preference; when the terminal side domain selection preference and the network side domain selection preference do not comprise the same preference, then according to priorities preset to the terminal side domain selection preference and the network side domain selection preference, the preference with the highest priority is searched, and the access domain or the service domain satisfying the preference with the highest priority is selected.

Correspondingly, the present invention also proposes a system for achieving domain selection in a communication system. Fig. 3 is a schematic view of the basic structure of the system proposed in the present invention for achieving domain selection. Referring to Fig. 3, the system proposed in the present invention mainly comprises: a terminal side domain selection preference storage unit for saving a terminal side domain selection preference; a network side domain selection preference storage unit for saving a network side domain selection preference; a domain processing unit, for respectively obtaining the terminal side domain selection preference and the network side domain selection preference from the terminal side domain selection preference storage unit and the network side domain selection preference storage unit, determining a domain corresponding to the terminal according to the obtained terminal side domain selection preference and the obtained network side domain selection preference, and transmitting the domain information corresponding to the terminal to a domain selection execution unit; and the domain selection execution unit for carrying out a domain selection for the terminal according to the domain information corresponding to the terminal.

In the system proposed in the present invention, the terminal side domain selection preference storage unit can be arranged in the terminal; the network side domain selection preference storage unit can be arranged in any one or more of a HSS, O&M, and an IMS network application server in an IMS network; the domain processing unit is arranged in existing equipment or newly added equipment in the IMS network, and when it is arranged in existing equipment, since the service CSCF (S- CSCF) in an IMS network is located in the home domain, and it is the control node of the whole IMS and is the execution node of the IMS session management, the domain processing unit can be arranged in this existing S-CSCF equipment, of course, the domain processing unit can also be arranged in any newly added special equipment according to the present invention; also, the domain selection execution unit can be arranged in the terminal and/or in the IMS network application server. In this way, a preferred structure of the system according to the present invention can be seen to Fig. 4.

Correspondingly, the present invention also proposes an IMS universal domain selection server. Fig. 5 is a schematic view of the basic structure of the IMS universal domain selection server proposed in the present invention. Referring to Fig. 5, in the present invention, the basic structure of the IMS universal domain selection server comprises: a terminal side domain information exchange unit for obtaining a terminal side domain selection preference, and for transmitting the terminal side domain selection preference to a domain decision-making unit; a network side domain information exchange unit for obtaining a network side domain selection preference, and for transmitting the network side domain selection preference to the domain decision-making unit; and the domain decision-making unit for determining a domain corresponding to the terminal according to the received terminal side domain selection preference and the received network side domain selection preference.

Figure 6 is a schematic view of a preferred structure of the IMS universal domain selection server proposed in the present invention. Referring to Fig. 5 and Fig. 6, in the IMS universal domain selection server proposed in the present invention, preferably, said terminal side domain information exchange unit can comprise particularly a terminal side access domain information exchange sub-unit and a terminal side service domain information exchange sub-unit, said network side domain information exchange unit comprises particularly a network side access domain information exchange sub-unit and a network side service domain information exchange sub-unit, and said domain decision- making unit comprises particularly an access domain decision- making sub-unit and a service domain decision-making sub- unit, and wherein the terminal side access domain information exchange sub-unit is used for obtaining the terminal side access domain selection preference from the terminal and for transmitting the terminal side access domain selection preference to the access domain decision-making sub-unit; the network side access domain information exchange sub-unit is used for obtaining the network side access domain selection preference from HSS and/or O&M, and for transmitting the network side access domain selection preference to the access domain decision-making sub-unit; the access domain decision-making sub-unit is used for determining an access domain corresponding to the terminal according to the received terminal side access domain selection preference and the received network side access domain selection preference; the terminal side service domain information exchange sub- unit is used for obtaining the terminal side service domain selection preference from the terminal and for transmitting the terminal side service domain selection preference to the service domain decision making sub-unit; the network side service domain information exchange sub-unit is used for obtaining the network side service domain selection preference from HSS and/or O&M, and for transmitting the network side service domain selection preference to the service domain decision-making sub-unit; and the service domain decision-making sub-unit is used for determining a service domain corresponding to the terminal according to the received terminal side service domain selection preference and the received network side service domain selection preference.

Referring to Fig. 6, said access domain decision-making sub- unit further transmits the access domain information corresponding to the terminal to the terminal side access domain information exchange sub-unit; said terminal side access domain information exchange sub- unit further transmits to the terminal the received access domain information corresponding to the terminal; said service domain decision-making sub-unit further transmits the service domain information corresponding to the terminal to the terminal side service domain information exchange sub-unit; and said terminal side service domain information exchange sub- unit further transmits to the terminal the received service domain information corresponding to the terminal.

Referring to Fig. 6, the server can also further comprise a network side domain result exchange unit used for transmitting the access domain information and the service domain information corresponding to the terminal transmitted by the access domain decision-making sub-unit and the service domain decision-making sub-unit to the IMS network application server in the IMS network; wherein the access domain decision-making sub-unit is further used for transmitting the access domain information corresponding to the terminal to the network side domain result exchange unit; and the service domain decision-making sub-unit is further used for transmitting the service domain information corresponding to the terminal to the network side domain result exchange unit .

Referring to Fig. 6, it is to be noted that, in the present invention, the terminal side access domain information exchange sub-unit can obtain the terminal side access domain selection preference by means of carrying out the information exchange process with the terminal through a pre-defined Sl interface; the terminal side service domain information exchange sub-unit can obtain the terminal side service domain selection preference by means of carrying out the information exchange with the terminal through a pre-defined S3 interface; the network side access domain information exchange sub-unit can obtain the network side access domain selection preference by means of carrying out the information exchange with any one or more of the HSS, the O&M and the IMS network application server via a pre-defined S2 interface; the network side service domain information exchange sub-unit can obtain the network side service domain selection preference by means of carrying out the information exchange with any one or more of the HSS, the O&M and the IMS network application server via a pre-defined S4 interface; and the network side domain result exchange unit can carry out the information exchange with the IMS network application server in the IMS network via a previously defined S5 interface. Wherein, each of the interfaces can be configured according to practical service requirements, for example, the Sl interface can be a Ut interface, the S5 interface can be a SIP protocol interface and so on.

Currently, the networks based on fixed or mobile access approaches are developing towards a full IP network based on IMS, for this reason, the solutions proposed in the present invention can be applied in various IP networks that are capable of providing load bearing, transmitting and signaling controls in telecom level services, that is to say they can be applied in various communication systems which use IMS networks for achieving service controls.

Generally, what described above are merely the preferred embodiments of the present invention, which are not for defining the protective scope of the present invention. Any modification, equivalent substitution, and improvement made within the spirit and principles of the present invention should be covered in the protective scope of the present invention .

In one aspect of the invention as depicted in Fig.7, a domain selection application server (AS) may retrieve user subscription information and operator access domain selection preference setting for each user equipment from a home subscriber server (HSS) . A user equipment (UE) may transmit its access domain preferences, e.g. a list of XML items containing priority of access networks, to the domain selection AS by using e.g. HTTP post message. The domain selection AS may, based upon the obtained information regarding the access domain selection preference from the both sides, determine a set of access domain selection rules for the UE and transmit the determined access domain rules to the UE by using, e.g. HTTP 200 OK message. Upon the receipt of the access selection rules from the domain selection AS, the UE may store them and follow the rules when accessing e.g. an IMS network. Alternately, the operator access domain selection preference setting may be obtained by configuring O&M system and transmitting them to the domain selection AS.

In another aspect of the invention as depicted in Fig.8, network service capabilities may be configured by an operator, which can be used to generate a set of service domain selection rules on the network side. The rules are transmitted to the domain selection AS. The domain selection AS may obtain the service capability of a UE by e.g. using IMS signaling message. The UE may transmit its service domain preferences to the domain selection AS by using e.g. HTTP post message. Likewise, the domain selection AS may determine a set of service domain selection rules for the UE based upon the obtained information from the both sides. The determined service domain selection rules may be transmitted to the UE by using, e.g. HTTP 200 OK message. Alternatively, the service domain selection rules may also be obtainable to a server, e.g. an IMS AS, by issuing a domain selection request for the UE to the domain selection AS. The domain selection AS may transmit the requested service domain selection rules in a message to the server. It is possible that domain selection AS may redirect the message to another domain with replaced UE identity as a tel URI (Uniform Resource Identifier) of the UE in the other domain. It is common in the art that a SIP URI request is replaced by a telephone number in PSTN if a user sets the domain selection preference with PSTN reachable. The server may adopt the service domain selection rules when accessing the UE. The modified request to UE may be routed to CSCF. CSCF may route the message to MGCF (Media Gateway Controller Function) for CS (Circuit Switched) or PSTN (Public Switched Telephone Network) breakout .

Functions of the domain selection apparatus and the user equipment described above may be implemented by code means, as software, and loaded into memory of a computer.

Claims

1. A method for domain selection in a communication system, the method comprising: obtaining domain selection preference from a user equipment, obtaining domain selection preference from a server, and determining a domain for the user equipment based on the domain selection preferences obtained from the user equipment and the server.

2. The method according to claim 1, further comprising transmitting information of the determined domain to the user equipment.

3. The method according to claim 1 or 2, further comprising receiving a domain selection request for the user equipment from an application server.

4. The method according to claim 3, further comprising transmitting information of the determined domain to the application server.

5. The method according to any of preceding claims, wherein the domain selection preference from the user equipment comprising at least one of service domain selection preference and access domain selection preference.

6. The method according to any of preceding claims, wherein the domain selection preference from the server comprising at least one of service domain selection preference and access domain selection preference.

7 The method according to any of preceding claims, wherein the determined domain comprising at least one of service domain and access domain.

8. The method according to any of preceding claims, wherein the server comprises one of a home subscriber server, a server responsible for operation and maintenance of the communication network or an application server.

9. The method according to any of preceding claims, wherein obtaining domain preference from the user equipment comprises receiving a hypertext transfer protocol message containing said domain preference.

10. A domain selection apparatus, comprising: a first unit configured to obtain domain selection preference from a user equipment; a second unit configured to obtain domain selection preference from a server; a domain decision-making unit configured to determine a domain for the user equipment based on the domain selection preferences obtained from the user equipment and the server.

11. The domain selection apparatus according to claim 10, wherein the domain selection preference from the server comprising at least one of service domain selection preference and access domain selection preference.

12. The domain selection apparatus according to claim 10 or 11, wherein the domain selection preference from the user equipment comprising at least one of service domain selection preference and access domain selection preference.

13. The domain selection apparatus according to any of claims 10 to 12, further comprising a third unit configured to receive a domain selection request for the user equipment from an application server and to transmit information of the determined domain to the application server.

14. The domain selection apparatus according to any of claims 10 to 13, wherein the first unit is further configured to transmit information of the determined domain to the user equipment .

15. The domain selection apparatus according to any of claims 10 to 14, wherein the determined domain comprising at least one of service domain and access domain.

16. The domain selection apparatus according to any of claims 10 to 15, wherein the server comprises one of a home subscriber server, a server responsible for operation and maintenance of the communication network or an application server.

17. The domain selection apparatus according to any of claims 10 to 16, wherein the first unit for obtaining domain selection preference from the user equipment, is configured to receive a hypertext transfer protocol message containing said domain preference.

18. A system for performing domain selection in a communication system, said system comprising:

a user equipment, a server, and a domain selection apparatus; wherein

the user equipment is configured to provide its domain selection preference to the domain selection server;

the server is configured to provide its domain selection preference to the domain selection server; and

the domain selection apparatus is configured to obtain domain selection preference from the user equipment, obtain domain selection preference from the server, determine a domain for the user equipment based on the domain preferences obtained from the user equipment and the server and transmit information of the determined domain to the user equipment .

19. The system according to claim 18, wherein the domain selection preference from the server comprising at least one of service domain selection preference and access domain selection preference.

20. The system according to claim 18 or 19, wherein the domain selection preference from the user equipment comprising at least one of service domain selection preference and access domain selection preference.

21. The system according to any of claims 18 to 20, wherein the determined domain comprising at least one of service domain and access domain.

22. The system according to any of claims 18 to 21, wherein the server comprises one of a home subscriber server, a server responsible for operation and maintenance of the communication network or an application server.

23. A computer program product comprising code means adapted to produce the steps of any one of claims 1-9 when loaded into the memory of a computer.