WO2008025708A2

WO2008025708A2 - Method and device for adjusting service carrier modes for mbms services in ims

Info

Publication number: WO2008025708A2
Application number: PCT/EP2007/058719
Authority: WO
Inventors: Li Zhu
Original assignee: Nokia Siemens Networks GmbH and Co KG
Current assignee: Nokia Solutions and Networks GmbH and Co KG
Priority date: 2006-08-28
Filing date: 2007-08-22
Publication date: 2008-03-06
Anticipated expiration: 2009-02-28
Also published as: CN101136814B; CN101136814A; WO2008025708A3

Abstract

This invention provides a type of communication method and device which supports MBMS services within IMS systems, including: providing UE with basic information for available services via a signal control channel; receiving competence information from UE to confirm that MBMS services are supported; receiving a service request from UE issued on the basis of said basic information; based on the competence information and service request, assisting UE and the MBMS service nodes to establish service carriers; receiving requests to adjust the service carrier mode from UE which are transmitted by the signal control channel; based on the requests to adjust the service carrier mode, instructing MBMS service nodes to change the service carrier mode for transmitting MBMS service data. Using the communications method and device in this invention, the service carrier mode may be adjusted in real time according to the current status of UE, thereby providing mobile clients with a superior mobile application service.

Description

A type of method and device for supporting MBMS services

Technical field

This invention involves a type of communications method and device, specifically a type of communications method and device for supporting MBMS services.

Technical background

As mobile communications technology has rapidly developed and mobile communications networks have continued to spread, people's demands on mobile communications have ceased to be satisfied by simple telephone answering and basic messaging services. A number of multimedia services which have developed rapidly on the internet, such as video on demand, TV broadcasts, video conferencing, online education and interactive games, are in the process of becoming part of the service expectations of mobile users.

In order to adjust to the development of mobile multimedia services and effectively use mobile network resources, the global standards organization 3GPP (3^rd Generation Partner Project) has proposed MBMS (Multimedia Broadcast / Multicast Services) . MBMS technology refers to point-to-multipoint transmission of data to multiple users from a data source via a shared transmission link.

Taking WCDMA (Wideband Code Division Multiple Access) networks as an example, in order to implement MBMS, it is necessary to add MBMS functionality to existing packet area nodes within the WCDMA network, such as SGSN (Serving GPRS Support Node) , GGSN (Gateway GPRS Support Node) , RNC (Radio Network Controller) and UE (User Equipment) ; it is also necessary to add an MBMS service node, i.e. a broadcast and multicast service centre (BM-SC) . A simplified model of the MBMS system structure is shown in Figure 1.

The reference points Gmb and Gi in Figure 1 show the interfaces between BM-SC and GGSN, with the Gmb interface providing control panel functions, while the Gi interface provides user interface functions. As a newly added node, BM- SC is the input for MBMS service providers, and is used to authorize and initiate services.

With regard to the existing nodes within the WCDMA network, required additional MBMS-related functions include:

(1) UE, which supports activating and deactivating MBMS services, supports parallel processing of MBMS services and non-MBMS services.

(2) UTRAN (Universal Mobile Telecommunications System (UTMS) Terrestrial Access Network, which includes RNC and Node B) , selects suitable service carrier modes according to the number of UEs subscribing to MBMS services and the usable wireless resources in the current zone. The service carrier modes include PTP (point-to-point) and PTM (point-to-multipoint) . In PTP service carrier mode, MBMS services are transmitted by a dedicated physical downward channel, while in PTM service carrier mode, MBMS services are transmitted by secondary public controlled physical channels. UTRAN supports core network initialization and termination of MBMS service transmission, supports receiving movements of MBMS service UEs between RNCs, and also supports other services which are transmitted in parallel to MBMS services.

(3) SGSN, which carries out network control of UEs which are receiving MBMS services, sends MBMS services to UTRAN, and completes the charge calculation functionality for MBMS services .

(4) GGSN, which establishes or releases user interface and control panel carriers for MBMS services according to instructions from BM-SC.

In addition to UTRAN, as shown in Figure 1, a UE located within a mobile network may also receive MBMS service data via wireless access networks GERAN (GSM/EDGE Radio Access Network, EDGE: Enhanced Data rates for GSM Evolution).

MBMS services have two working modes, which are broadcast and multicast. Broadcast mode means that multimedia data is sent unidirectionally from a service source to all UEs within the broadcast service zone, and in this mode, it is not necessary for UEs to register to receive broadcast data; multicast mode is similar to broadcast mode, however, the UEs which may receive the group broadcast data are limited to registered UEs, and when the number of UEs receiving multicast data within a zone is too low, the PTP service carrier mode may be selected to send multicast data, thereby reducing interference with other wireless links.

The process of implementing MBMS services within WCDMA grouped networks is described briefly below with the aid of Figure 2. - Registration stage (not required for broadcast mode) : Establish a relationship between the UE and the MBMS service provider (step SlO) . Once registration is complete, the UE may receive multicast data, and the MBMS service provider charges for the MBMS services provided.

- Service announcement stage: The MBMS service source provides basic information regarding the MBMS services which will be sent, to the UE (step S20)

- UE joining stage (not required for broadcast mode) : Based on the service information provided during the service announcement stage, the UE becomes a member of the multicast group for an MBMS service (step S30) . As the UE will be charged for the MBMS services received after joining the multicast group, it is also necessary to execute an identity authentication operation between the UE and the MBMS service provider during this stage.

- Dialog start stage: UTRAN allocates resources for MBMS, and establishes service carriers, and BM-SC prepares to transmit MBMS services (step S40) .

- MBMS instruction stage: The UE is instructed to carry out preparatory tasks for receiving MBMS services (step S50).

- Data transmission stage: MBMS service data is sent to the UE. In multicast mode, the MBMS service data is encrypted

(step S60) .

- Dialog end stage: After transmission of MBMS service data is complete, the resources used for MBMS service transmission are released (step S70).

- UE leaving stage (not required in broadcast mode) : The UE cancels its registration for multicast services, and ceases to receive the multicast services (step S80). It is evident from the process for implementing MBMS services described above that, as the carrier which transmits MBMS service data is established during the dialog start stage, it is extremely difficult to adjust the service carrier mode in real time based on the current state of the UE during the MBMS service transmission process.

For example, when a UE which is currently receiving MBMS service data moves outside the MBMS service coverage area, even if the UE is in a state in which it is unable to receive MBMS service data at this moment, as no dialog end message has been received from the UE, BM-SC continues to transmit MBMS service data, and the client will therefore continue to pay the corresponding service charges.

As another example, if a UE which is currently receiving MBMS service data wishes to increase the quality of service (QoS) of the MBMS services under transmission, or the client does not wish the services that are currently being used (such as mobile TV or mobile telephone conferencing) to be cut off as a result of leaving the MBMS service coverage area, as existing MBMS system structures are often unable to adjust the service carrier mode in real time, it is inevitable that the user experiences certain shortcomings within the mobile service.

Content of the invention

The object of this invention is to provide a type of communication method which supports MBMS services and a device which is used to implement the method in the invention, which is capable of adjusting the service carrier mode in real time according to the current state of the UE, thereby providing a superior mobile application service for mobile users.

The object of this invention is achieved using the following technical solution: A type of communication method which supports MBMS services within IMS systems, including the following steps: a) It provides UE with basic information for available services via a signal control channel; b) It receives competence information from UE to confirm that MBMS services are supported, in which said competence information indicates that the UE has the capability to receive the available services through the MBMS mode; c) It receives a service request from UE issued on the basis of said basic information; d) Based on the competence information and service request, it assists UE and the MBMS service nodes to establish service carriers, in order to allow the MBMS service node to transmit service data to the UE via the service carrier; e) It receives requests to adjust the service carrier mode from UE which are transmitted by the signal control channel; f) Based on the requests to adjust the service carrier mode, it instructs MBMS service nodes to change the service carrier mode for transmitting MBMS service data.

In step (a) , broadcast mode, PUSH mechanism or URL mode can all be used to provide basic information to the UE. The basic information includes at least: Media information for available services. Step (d) includes:

Based on the service request, the information used for MBMS service transmission is transmitted to the MBMS service node;

The corresponding parameters for use in MBMS service transmission are received from the MBMS service node;

These parameters are transmitted to the UE via said signal control channel, in order to allow the UE to establish service carriers with the MBMS service node in accordance with the parameters .

The information used for MBMS service transmission includes at least the media information and the deployment information for the UE.

The parameters used for MBMS service transmission include at least: Information used to transmit said media information and information used to allow the UE to become a member of the

MBMS service node multicast group.

Step (f) includes:

Based on the request to adjust the service carrier mode, the

MBMS service node is instructed to cease transmitting MBMS service data.

Step (f) includes:

Based on the request to adjust the service carrier mode, the

MBMS service node is instructed to change the service carrier mode, to allow the UE to receive MBMS service data through the changed service carrier.

The service carrier modes include: PTP mode and PTM mode.

A type of communications method which supports MBMS services within IMS systems, which is executed by one UE, including the following steps: a) Basic information is received on available services from an application server via a signal control channel; b) Based on the basic information, it detects whether the available services can be received through the MBMS mode. c) If it is possible to receive the available services through the MBMS mode, then a competence information message is sent to the application server, to indicate that the UE has the capability to receive the available services through the MBMS mode . d) Based on said basic information, a service request is sent to the application server. e) Parameters used for MBMS service transmission are received from the application server, to allow the establishment of service carriers with an MBMS service node, and thereby receiving service data transmitted by the MBMS service node through the service carrier. f) A request to adjust the service carrier mode is sent to the application server via the signal control channel.

Step (b) includes:

Based on the deployment information for the UE, it determines whether the UE is able to receive the available services through the MBMS mode.

The basic information includes at least the media information for the available services, and step (b) also includes the following:

Based on the deployment information for the UE, it determines whether the UE has the capability for parallel processing of services, in order to ascertain whether the UE is able to receive the media information in parallel through the MBMS mode .

The parameters used in MBMS service transmission include at least: Information used to transmit said media information and information used to allow the UE to become a member of the MBMS service node multicast group, in addition to which step (e) includes:

Based on these parameters, it joins the MBMS service node multicast;

Based on the wireless resources allocated by the access network, it establishes service carriers with the MBMS service node;

MBMS service data transmitted by the MBMS service node is received via the service carrier. Step (f) includes:

When the UE leaves the MBMS service coverage area, a request is sent to adjust the service carrier mode to the application server via the signal control channel. Step (f) includes:

When the UE wishes to adjust the service quality of the MBMS services, a request is sent to adjust the service carrier mode to the application server via the signal control channel. Step (f) includes:

When the UE wishes to receive different media resource information, a request is sent to adjust the service carrier mode to the application server.

The media resource information includes at least: background services and stream media services.

The service carrier modes include: PTP mode and PTM mode. The access network may be any one of WLAN, GPRS, WCDMA, TD- SCDMA and CDMA2000.

A type of communication method for supporting MBMS services within IMS systems, which includes the following steps: a) The information used in MBMS service transmission is received from an application server; b) Based on the information used in MBMS service transmission, the corresponding parameters for use in MBMS service transmission are provided to the application server; c) Using these parameters, service carriers are established with a UE for use with MBMS services, in order to transmit service data to the UE via the service carrier, during which the UE obtains the parameters through the application server. d) The instruction to adjust the service carrier mode which transmits the MBMS service data, is received from the application server. e) Based on this instruction, the service carrier is adjusted. The information used for MBMS service transmission includes at least the media information and the deployment information for the UE.

The parameters used in MBMS service transmission include at least: Information used to transmit said media information and information used to allow the UE to become a member of the

MBMS service node multicast group.

Step (c) includes:

Based on said parameters, the UE is permitted to join the MBMS service multicast;

Based on the wireless resources allocated by the access network, service carriers are established with the UE.

MBMS service data is transmitted to the UE via the service carrier .

The access network may be any one of WLAN, GPRS, WCDMA, TD-

SCDMA and CDMA2000.

Step (e) includes: Transmission of MBMS service data is stopped in accordance with said instruction.

Step (e) includes:

The service carrier mode is changed according to the instruction, and the MBMS service data is transmitted using the changed service carrier.

The service carrier modes include: PTP mode and PTM mode.

A type of communications device for supporting MBMS services in IMS systems, including:

MBMS service initiation module, which includes:

A module which provides basic information for available services to a UE via a signal control channel;

Competence information is received from the UE, in order to determine the module which supports MBMS services, in which the competence information indicates that the UE has the capability to receive said available services via the MBMS mode . MBMS service assistance module, including:

A module which receives a service request issued by the UE based on the basic information;

In accordance with the competence information and the service request, a module which assists the UE to establish service carriers with an MBMS service node, in order that the MBMS service node is able to transmit service data to the UE through the service carrier;

A module which receives requests to adjust the service carrier mode transmitted by the UE through the signal control channel;

In accordance with requests to adjust the service carrier mode, a module which instructs the MBMS service node to adjust the service carrier mode which transmits the MBMS service data.

The basic information includes at least: Media information for said available services, a module which assists the UE to establish service carriers with the MBMS service node, including :

In accordance with the service request, a module which transmits the information used for MBMS service transmission to the MBMS service node;

A module which receives the corresponding parameters used for

MBMS service transmission from the MBMS service node;

A module which transmits the parameters to the UE via the signal control channel, so that the UE establishes service carriers with the MBMS service node based on the parameters.

The information transmitted by the MBMS service node includes at least the media information and deployment information for the UE; the parameters used for MBMS service transmission include at least: information used to transmit the media information and information used to allow the UE to become a member of the MBMS service node multicast group.

A module which instructs the MBMS service node to adjust the service carrier mode which transmits MBMS service data, which is able to instruct the MBMS service node to cease transmission of MBMS service data in accordance with the request to adjust the service carrier mode; and/or is able to instruct the MBMS service node to change the service carrier mode in accordance with the request to adjust the service carrier mode, so that the UE receives MBMS service data through the changed service carrier.

A type of client terminal which is used to execute the communications method for supporting MBMS service within IMS systems, including:

Competence information exchange module, which includes:

A module which receives basic information on available services from an application server via a signal control channel; and

A module which detects whether the available services can be received through the MBMS mode, in accordance with the basic information;

In addition, a module, which, if it is possible to receive the available services through the MBMS mode, sends a competence message to the application server, in order to indicate that the UE is capable of receiving the available services through the MBMS mode; An MBMS service execution module, which includes:

A module which is used to send a service request to the application server based on the basic information; and

A module which is used to receive parameters used for MBMS service transmission from the application server, in order to establish service carriers with an MBMS service node, in order to receive service data from MBMS service node transmission through the service carrier;

An adjust service carrier request module, used to send a request to adjust the service carrier mode to the application server via the signal control channel.

A module which detects whether is possible to receive the available services through the MBMS mode, including: a module which determines whether the UE is able to receive the available services through the MBMS mode based on the deployment information for the UE; and/or a module which determines whether the UE is capable of parallel processing of services based on the deployment information for the UE, in order to ascertain whether the UE is able to receive the media information for the available services involved in the basic information in parallel through the MBMS mode.

The parameters used for MBMS service transmission include at least: Information used to transmit the media information and information used to allow the UE to become a member of the

MBMS service node multicast group, and said MBMS service execution module further includes:

A module which joins the MBMS service mode multicast according to the parameters;

A module which establishes service carriers with the MBMS service node in accordance with the wireless resources allocated by the access network;

A module which receives MBMS service data from MBMS service node transmission through the service carrier.

When the UE leaves the MBMS service coverage area, or the UE wishes to adjust the service quality of MBMS services, or the

UE wishes to receive different media resource information, said adjust service carrier request module sends the request to adjust the service carrier mode to the application server via the signal control channel.

A type of communication device to support MBMS services within

IMS systems, including:

An MBMS service support module, which includes:

A module used to receive information used in MBMS service transmission from an application server;

A module which provides the corresponding parameters for use in MBMS service transmission to the application server in accordance with the MBMS service transmission information; An MBMS service transmission module, which includes:

A module which uses the parameters to establish service carriers used for MBMS services with a UE (client terminal) , in order to transmit service data to the UE through the service carrier, in which the UE obtains the parameters from the application server; A service carrier adjustment module, which includes:

A module used to receive instructions to adjust the service carrier mode for transmitting MBMS service data from the application server;

A module which adjusts the service carrier in accordance with the instruction.

The information used in MBMS service transmission includes at least the media information and deployment information for the UE; the parameters used for MBMS service transmission include at least: Information used to transmit the media information and information used to allow the UE to become a member of the MBMS service node multicast group.

A module which established service carriers used for MBMS services with the UE, including:

A module which permits the UE to join the MBMS service multicast in accordance with the parameters; A module which establishes service carriers with the UE in accordance with the wireless resources allocated by the access network;

A module which transmits MBMS service data to the UE through the service carrier.

A module which adjusts the service carrier, including: a module which ceases transmission of data on MBMS services in accordance with the instruction; and/or a module which changes the service carrier mode in accordance with the instruction, and transmits data on MBMS services through the changed service carrier.

Explanation of the drawings

The following reference drawings are used to describe the invention in further detail using specific exemplary embodiments, in which:

Figure 1 is a schematic diagram of a conventional MBMS system structure .

Figure 2 is a schematic diagram of a conventional MBMS service implementation process.

Figure 3 is a schematic diagram of the integration of MBMS systems structures with IMS systems in accordance with a specific exemplary embodiment of this invention.

Figure 4 is a schematic diagram of the integration of a WCDMA network-based MBMS system with an IMS system.

Figure 5 is a flow chart of a communications method which supports MBMS services in accordance with a specific exemplary embodiment of this invention.

Figure 6 is a schematic diagram of a communications system for executing the method shown in Figure 5.

Identical symbols within all the diagrams indicate similar or corresponding characteristics or functions.

Specific exemplary embodiments In the communications method for supporting MBMS services proposed in this invention, the properties of a SIP (Session Initiation Protocol) -based, access and carrier technology- independent IMS system (IP Multimedia Subsystem) are used to allow the UE to send information on adjusting the service carrier mode to the IMS ' s application server AS via the IMS system's signal control layer during the MBMS service transmission process; in addition, information is forwarded to BM-SC by IMS AS, thereby allowing BM-SC, which is currently in the process of transmitting MBMS services, to adjust its carrier mode in real time, in order to meet user requirements.

Figure 3 is a schematic diagram of the introduction of an IMS subsystem into an MBMS system structure. This differs from the conventional MBMS system structure shown in Figure 2 in that in Figure 3 there is a client terminal located within the wireless communication network, for example: a mobile telephone establishes signal pathways with the access network GERAN, the IMBS carrier layer, which is made up of the SGSN and the GGSN, and the IMS signal control layer, which is made of up the CSCF (Call Session Control Function) and the HSS (Home Subscriber Server) . The SGSN and the GSGN which made up the IMS carrier layer may reuse the SGSN and GSGN within the MBMS system structure through the corresponding deployment. IMS AS itself, or third parties using IMS AS, provide MBMS services such as mobile television and mobile conferencing. BM-SC, which is located within the MBMS system structure, is not only able to receive control information from IMS AS, but is also capable of transmitting the MBMS service data provided by IMS AS to the client terminal through the grouped Communications networks (GGSN and SGSN) and the access network GERAN/UUTRAN.

Figure 4 schematically shows the interrelationship between the signal pathways established between IMS AS and the various UEs located within the wireless communications network, the WCDMA- based MBMS system, and the IMS system.

In the text below and Figure 5, an example using a WCDMA network as the access network is given, in order to describe in detail the communication method for supporting MBMS services within IMS systems in this invention. As the IMS system can reuse the carrier layer equipment of the MBMS system, in order to more clearly describe the process of the client terminal instructing BM-SC through the IMS AS and thereby adjusting the carrier mode used for MBMS service transmission, Figure 5 shows only the signal transmission relationship between the client terminal UE, the broadcast/multicast centre BM-SC and the IMS application server IMS AS, and disregards the active CSCF which initiates the pathways between IMS AS and UE, in addition to ignoring the wireless carrier established between UE and BM-SC and the RAN, SGSN and GGSN network entities required to transmit MBMS services .

As shown in Figure 5, the UE first establishes signal pathways with IMS AS through the carrier layer and signal control layer of the IMS system (step SlOO) . Once the signal pathways are established, the UE sends messages to the IMS AS via the signal control channel. During the process of establishing signal pathways, the IMS AS can carry out identity authentication of the UE using the user information stored by the user server HSS within the IMS system.

Once a UE moves into the MBMS service coverage area (SIl) 2, if the IMS AS detects that the UE has pre-ordered MBMS services, the IMS AS will provide basic information on available services to the UE via the signal control channel (S120) . The IMS AS may provide this basic information to the UE by any one of the following modes: broadcast, PUSH mechanism (e.g. wireless application protocol WAP, short messaging service SMS and multimedia messaging service MMS) and URL (universal resource locator, e.g. HTTP or FTTP) . This basic information must include at least the media information for the available services. The media information contains the specific application of the available services (e.g. weather forecasts, advertisements, news broadcasts, sports programs or audio^¬ visual entertainment) and the media type of the available services (e.g. text, audio channel, video channel or pictures) .

According to the basic information received, the UE detects whether it is able to receive the available service data through the MBMS mode based on the UE ' s deployment information. This deployment information includes whether the UE is capable of receiving the service data through the MBMS mode, i.e. whether the UE has the ability to activate and deactivate MBMS services, and whether the UE is capable of carrying out parallel processing of MBMS services and non-MBMS services. For example, some UEs are only capable of receiving MBMS service data in text format while a telephone call is being made.

If the UE has the capability of receiving the available services through the MBMS mode, the UE sends a competence message to the IMS AS to indicate that the UE is able to receive data for the available services through the MBMS mode (step S130) . Within this information, the UE can also further indicate that it wishes to increase the quality of service for the MBMS service.

After receiving the competence information from the UE, the IMS AS determines whether it is able to provide MBMS services to the UE in accordance with the request, for example, to provide the service quality requested by the UE. At this stage, the IMS AS may exchange competences for MBMS service transmission with the UE (step S140) .

Once the UE and the IMS AS have mutually confirmed that they are capable of supporting MBMS service transmission, the UE sends a service request to the IMS AS in accordance with said basic information on the available services (step S150) . The service request includes the media information selected by the user and the UE ' s deployment information. In addition, the service request may specify whether the UE wishes to switch to PTP service carrier mode to continue receiving service data after leaving the MBMS service coverage area.

Once the service request has been received, with regard to the selected media information, the IMS negotiates an encoding format (codec) for transmitting MBMS service data with the UE

(step 160) . In addition, the IMS AS sends information used for MBMS service transmission, such as the selected media information and the UE ' s deployment information, to the BM-SC

(step S170) . How the link between the IMS AS and the BM-SC herein is established does not fall within the scope of this invention. The IMS AS can establish a link with the BM-SC in a variety of ways. For example, if IP addresses are used for the network addresses for the BM-SC, the IMS AS can establish a link with the BM-SC using DNS (domain name server) .

After receiving the information for use in MBMS service transmission, the BM-SC allocates an MBMS service ID to be used in MBMS service transmission to the UE based on the user deployment information; based on the selected media information, the BM-SC determines the port number of the transmission layer used to transmit media information and the multicast address. Next, the BM-SC supplies information including the port number and MBMS service ID to the IMS AS as the parameters for MBMS service transmission use (step S180).

After receiving the parameters from the BM-SC, the IMS AS sends the parameters to the UE via the signal control channel (step S190) .

Using these parameters, a service carrier may be established between the UE and the BM-SC, so that the UE receives MBMS service data from the BM-SC through the service carrier (step S200) . The process of establishing a service carrier and transmitting MBMS service data includes:

First, the UE joins the corresponding MBMS service multicast group in accordance with the MBMS service ID in said parameters. As identity authentication of the UE has already been carried out during the signal pathway establishment stage (SlOO) above, the UE can use the results of this authentication stage during the joining stage to successfully join the MBMS service multicast group.

Once the UE becomes a member of the MBMS service multicast group, the RNC allocates wireless resources for executing the various functional entities of the MBMS services, thereby establishing service carriers for the UE and the BM-SC. The RNC may determine the service carrier mode based on the number of members of the multicast group and the current available wireless resource situation, or may choose the optimal service carrier mode for the UE ' s unique requirements.

Once a service carrier mode has been established between the UE and the BM-SC, the multimedia information from the IMS AC can then be transmitted to the UE in the MBMS mode using the codec that was negotiated.

The signal control channel between the UE and the IMS is maintained throughout the entire process of MBMS service transmission, so that if the UE wishes to change the service carrier mode, it can send a request to adjust the service carrier mode, which will be transmitted via the signal control channel to the IMS AS (step S210) . After receiving such a request, the IMS AS is able to immediately instruct the BM-SC to adjust the service carrier mode (step S220). Furthermore, the BM-SC can make the corresponding adjustment to its service carrier mode in accordance with the instruction from the IMS AS (step S220) .

Specifically, if the UE leaves the MBMS service coverage area, then in step S210, the UE sends a request to the IMS AS to request that it cease transmission of MBMS service data. Once this request has been received, in step S220, the IMS AS instructs the BM-SC to cease transmitting MBMS service information. Once the instruction has been received, in step S230, the BM-SC ceases transmission of MBMS services while also ceasing to accrue charges.

If the UE wishes to leave the MBMS service coverage area, the switch to PRP service carrier mode is made and the UE continues to receive the service data. In step S210, the UE can send an adjust service carrier mode request, requesting that the service carrier mode is switched to PTP mode. Once the request is received, in step S220, the IMS AC instructs the BM-SC to switch the service carrier mode. Next, in step S230, the BM-SC switches to PTP service carrier mode in accordance with the instruction, and transmits service data through the changed service carrier.

In addition, if the UE indicated in the service request it sent in step S150 that the service carrier mode should automatically be switched to PTP when the UE leaves the MBMS service coverage area to continue transmission of service data, when the UE leaves the MBMS service coverage area, the IMS may then automatically instruct the BM-SC to switch to PTP service carrier mode, so that the BM-SC uses PTP service carrier mode and continues to transmit service data to the UE.

In the same way, if the UE wishes to adjust the quality of service of MBMS services during the process of receiving MBMS service data, for example if the user wishes to make the video channel image clearer, then the UE may send an adjust service carrier mode request to the IMS AS through the signal control channel. After the IMS AS receives this request, it instructs the BM-SC to switch the service carrier mode. The BM-SC then starts to transmit server data using the switched service carrier mode in accordance with the request to improve quality of service made by the user.

In addition, the user can also alter which media resource information it wishes to receive via the signal control channel during the process of receiving MBMS service data. For example, suppose the UE is receiving download-type background services through the MBMS mode; if the user wishes to receive simultaneous download/broadcast streaming media services through the MBMS mode at this time, the UE can send an adjust service carrier mode request through the signal control channel, so that the IMS AS instructs the BM-SC to switch the service carrier mode; once the BM-SC switches to the corresponding service carrier mode in accordance with the IMS AS ' s instruction, the UE may then receive streaming media MBMS service data transmitted by the BM-SC through the switched service carrier. The communication method for supporting MBMS services in this invention, as described above with Figure 5, may be implemented via a software method or a hardware method, and may also be implemented using a method which combines software and hardware .

Figure 6 shows a system schematic diagram of the implementation of MBMS services within an IMS system for an exemplary embodiment of this invention. The formations of UE, BM-SC and IMS AS in this system are shown in the diagram, and components or modules which are identical to those of conventional UEs, BM-SCs and IM ASs are not shown.

As shown in Figure 6, the UE includes three modules, each of which carries out the corresponding steps of the communications method for supporting MBMS services described above. Specifically, competence information exchange module 10, used to exchange competence information regarding whether MBMS services are supported with the IMS AS (i.e. steps S130 and S140 above); MBMS service execution module 12, used to establish service carriers and receive MBMS service data through the established serviced carriers (i.e. steps S150, S160 and S200 above); and adjust service carrier request module 15, used to send requests to adjust the service carrier mode to the IMS AS via the signal control channel in accordance with the current state of the user (i.e. step S210 above) .

The IMS AS includes two modules, MBMS service initiation module 20, used to provide the UE with basic information for the available services and exchange competence information regarding whether MBMS services are supported with the UE (e.g. steps S120 and S160 above); and MBMS service assistance module 22, used to assist the UE to establish service carriers with the BM-SC, thereby enabling the BM-SC to transmit MBMS service data to the UE through the established service carriers, and to respond to requests from the UE to adjust the service carrier mode by instructing the BM-SC to adjust the carried mode for transmitting MBMS services (e.g. steps S170, S190 and S220 above) .

BM-SC includes three modules: MBMS service support module 30, used to provide IMS AS with parameters used for MBMS service transmission in accordance with the basic information for MBMS service transmission received from the IMS AS (e.g. step S180 above); MBMS service transmission module 32, used to establish service carriers and transmit MBMS service data through the established service carriers (e.g. step S200 above); and service carrier adjustment module 35, used to adjust the service carrier mode correspondingly in accordance with instructions from the IMS AS (e.g. step S220 above) .

As described above, during the MBMS service transmission process of the communications method and device for supporting MBMS services in this invention, as the control signal links within the IMS system can be reused, user requests to adjust the service carrier mode are sent to the BM-SC through the IMS AS; consequently, within the communications system which is executing the method, it is possible to adjust the carrier mode for transmitting MBMS services in real time, based on the user's current state (e.g. whether the user has left the MBMS service coverage area and whether the quality of service must be raised) . Thus, users located within the mobile network have access to a rich and varied selection of multimedia services, while also enjoying superior network service.

In addition, as the UE can share the results of carrying out identity verification with the IMS AS system when joining MBMS service multicast groups, the communications system in this invention avoids the complications of using multiple security keys .

The IMS system utilizes SIP, and this allows different multimedia service providers to provide a greater range of more attractive IP mobile services to users based on a single, standardized service platform.

Due to the fact that the IMS system is unconnected to the access network, MBMS services can be transmitted to mobile users through a variety of access networks. Such wireless access networks include, but are not limited to, WLAN

(Wireless Local Area Network) , GPRS, WCDMA and TD-SCSDMA (Time Division-Synchronous Code Division Multiple Access) . CDMA2000 may also be selected as the access network, as the broadcast and multicast mechanism and the working modes of its BCMS

(Broadcast and Multicast Service) technology are similar to MBMS.

Technical personnel working in this field should be aware that further improvements of various types may be made to the communications method for supporting MBMS services and the communications system for executing this method published in this invention, while continuing to operate based on the content of this invention. Consequently, the scope of protection of this invention should be determined by the content of the attached claims.

Claims

1. A type of communication method and device which supports MBMS services within IMS systems, including the following processes : a) it provides UE with basic information for available services via a signal control channel; b) it receives competence information from UE to confirm that MBMS services are supported, in which said competence information indicates that the UE has the capability to receive the available services through the MBMS mode; c) it receives a service request from UE issued on the basis of said basic information; d) based on the competence information and service request, it assists UE and the MBMS service nodes to establish service carriers, in order to allow the MBMS service node to transmit service data to the UE via the service carrier; e) it receives requests to adjust the service carrier mode from UE which are transmitted by the signal control channel; f) based on the requests to adjust the service carrier mode, it instructs MBMS service nodes to change the service carrier mode for transmitting MBMS service data.

2. The communications method as claimed in claim 1, characterized in that in step (a) , the broadcast mode, PUSH mechanism or URL mode can all be used to provide basic information to the UE.

3. The communications method as claimed in claim 1, characterized in that the basic information includes at least: media information for available services.

4. The communications method as claimed in claim 3, characterized in that step (d) includes:

Based on the service request, the information used for MBMS service transmission is transmitted to the MBMS service node; The corresponding parameters for use in MBMS service transmission are received from the MBMS service node; These parameters are transmitted to the UE via said signal control channel, in order to allow the UE to establish service carriers with the MBMS service node in accordance with the parameters .

5. The communications method as claimed in claim 4, characterized in that the information used for MBMS service transmission includes at least the media information and the deployment information for the UE.

6. The communications method as claimed in claim 4, characterized in that the parameters used for MBMS service transmission include at least: Information used to transmit said media information and information used to allow the UE to become a member of the MBMS service node multicast group.

7. The communications method as claimed in claim 1, characterized in that in step (f) : based on the request to adjust the service carrier mode, the MBMS service node is instructed to cease transmitting MBMS service data.

8. The Communications method as claimed in claim 1, characterized in that in step (f) : based on the request to adjust the service carrier mode, the MBMS service node is instructed to change the service carrier mode, to allow the UE to receive MBMS service data through the changed service carrier.

9. The communications method as claimed in claim 1, characterized in that the service carrier modes include: PTP mode and PTM mode.

10. A type of communications method which supports MBMS services within IMS systems which is executed by a single UE, including the following steps: a) it receives basic information on available services from an application server via a signal control channel; b) based on the basic information, it detects whether the available services can be received through the MBMS mode. c) if it is possible to receive the available services through the MBMS mode, it then sends a competence information message to the application server, to indicate that the UE has the capability to receive the available services through the MBMS mode . d) based on said basic information, it sends a service request to the application server. e) it receives parameters used for MBMS service transmission from the application server, to allow the establishment of service carriers with an MBMS service node, and thereby receive service data transmitted by the MBMS service node through the service carrier. f) it sends a request to adjust the service carrier mode to the application server via the signal control channel.

11. The communications method as claimed in claim 10, characterized in that step (b) includes:

Based on the deployment information for the UE, this determines whether the UE is able to receive the available services through the MBMS mode.

12. The communications method as claimed in claim 10, characterized in that the basic information includes at least the media information for the available services, and step (b) also includes the following: based on the deployment information for the UE, it determines whether the UE has the capability for parallel processing of services, in order to ascertain whether the UE is able to receive the media information in parallel through the MBMS mode .

13. The communications method as claimed in claim 10, characterized in that the parameters used in MBMS service transmission include at least: information used to transmit said media information and information used to allow the UE to become a member of the MBMS service node multicast group, in addition to which step (e) includes: based on these parameters, it joins the MBMS service node multicast; based on the wireless resources allocated by the access network, service carriers are established with the MBMS service node; MBMS service data transmitted by the MBMS service node is received via the service carrier.

14. The communications method as claimed in claim 10, characterized in that in step (f) : when the UE leaves the MBMS service coverage area, a request is sent to adjust the service carrier mode to the application server via the signal control channel.

15. The communications method as claimed in claim 10, characterized in that in step (f) : when the UE wishes to adjust the service quality of the MBMS services, a request is sent to adjust the service carrier mode to the application server via the signal control channel.

16. The communications method as claimed in claim 10, characterized in that in step (f) : when the UE wishes to receive different media resource information, a request is sent to adjust the service carrier mode to the application server.

17. The communications method as claimed in claim 10, characterized in that the media resource information includes at least: background services and stream media services.

18. The communications method as claimed in claim 10, characterized in that the service carrier modes include: PTP mode and PTM mode.

19. The communications method as claimed in claim 13 characterized in that the access network may be any one of WLAN, GPRS, WCDMA, TD-SCDMA and CDMA2000.

20. A type of communication method for supporting MBMS services within IMS systems, which includes the following steps : a) Receive the information used in MBMS service transmission from an application server; b) Based on the information used in MBMS service transmission, the corresponding parameters for use in MBMS service transmission are provided to the application server; c) Using these parameters, service carriers are established with a UE for use with MBMS services, in order to transmit service data to the UE via the service carrier, during which the UE obtains the parameters through the application server. d) The instruction to adjust the service carrier mode which transmits the MBMS service data, is received from the application server. e) Based on this instruction, it adjusts the service carrier.

21. The communications method as claimed in claim 20, characterized in that the information used for MBMS service transmission includes at least the media information and the deployment information for the UE.

22. The communications method as claimed in claim 20, characterized in that the parameters used in MBMS service transmission include at least: Information used to transmit said media information and information used to allow the UE to become a member of the MBMS service node multicast group.

23. The Communications method as claimed in claim 20, characterized in that in step (c) :

MBMS service data is transmitted to the UE via the service carrier .

24. The communications method as claimed in claim 23, characterized in that the access network may be any one of WLAN, GPRS, WCDMA, TD-SCDMA and CDMA2000.

25. The communications method as claimed in claim 20, characterized in that in step (e) : transmission of MBMS service data is stopped in accordance with said instruction.

26. The communications method as claimed in claim 20, characterized in that in step (e) : the service carrier mode is changed according to the instruction, and the MBMS service data is transmitted using the changed service carrier.

27. The communications method as claimed in claim 20, characterized in that the service carrier modes include: PTP mode and PTM mode.

28. A type of communications device for supporting MBMS services in IMS systems, including:

MBMS service initiation module, which includes:

In accordance with requests to adjust the service carrier mode, a module which instructs the MBMS service node to adjust the service carrier mode which transmits the MBMS service data .

29. The communication device as claimed in claim 28, characterized in that the basic information includes at least: media information for said available services, a module which assists the UE to establish service carriers with the MBMS service node, including: a module which transmits the information used for MBMS service transmission to the MBMS service node in accordance with the service request; a module which receives the corresponding parameters used for

MBMS service transmission from the MBMS service node; a module which transmits the parameters to the UE via the signal control channel, so that the UE establishes service carriers with the MBMS service node based on the parameters.

30. The communication device as claimed in claim 29, characterized in that the information transmitted by the MBMS service node includes at least the media information and deployment information for the UE; the parameters used for MBMS service transmission include at least: information used to transmit the media information and information used to allow the UE to become a member of the MBMS service node multicast group.

31. The communication device as claimed in claim 28, characterized in that a module which instructs the MBMS service node to adjust the service carrier mode which transmits MBMS service data, which is able to instruct the MBMS service node to cease transmission of MBMS service data in accordance with the request to adjust the service carrier mode; and/or is able to instruct the MBMS service node to change the service carrier mode in accordance with the request to adjust the service carrier mode, so that the UE receives MBMS service data through the changed service carrier.

32. A type of client terminal which is used to execute the communications method for supporting MBMS service within IMS systems, including:

A competence information exchange module, which includes:

33. The client terminal as claimed in claim 32, characterized in that a module which detects whether is possible to receive the available services through the MBMS mode, including: a module which determines whether the UE is able to receive the available services through the MBMS mode based on the deployment information for the UE; and/or a module which determines whether the UE is capable of parallel processing of services based on the deployment information for the UE, in order to ascertain whether the UE is able to receive the media information for the available services involved in the basic information in parallel through the MBMS mode.

34. The client terminal as claimed in claim 32, characterized in that the parameters used for MBMS service transmission include at least: Information used to transmit the media information and information used to allow the UE to become a member of the MBMS service node multicast group, and said MBMS service execution module further includes:

35. The client terminal as claimed in claim 32, characterized in that when the UE leaves the MBMS service coverage area, or the UE wishes to adjust the service quality of MBMS services, or the UE wishes to receive different media resource information, said adjust service carrier request module sends the request to adjust the service carrier mode to the application server via the signal control channel.

36. A type of communication device to support MBMS services within IMS systems, including:

An MBMS service support module, which includes:

A module which uses the parameters to establish service carriers used for MBMS services with a UE (client terminal), in order to transmit service data to the UE through the service carrier, in which the UE obtains the parameters from the application server; A service carrier adjustment module, which includes:

A module which adjusts the service carrier in accordance with the instruction.

37. The communication device as claimed in claim 36, characterized in that the information used in MBMS service transmission includes at least the media information and deployment information for the UE; the parameters used for MBMS service transmission include at least: Information used to transmit the media information and information used to allow the UE to become a member of the MBMS service node multicast group.

38. The communication device as claimed in claim 36, characterized as follows: a module which establishes service carriers used for MBMS services with the UE, including:

A module which permits the UE to join the MBMS service multicast in accordance with the parameters;

A module which establishes service carriers with the UE in accordance with the wireless resources allocated by the access network;

39. The communication device as claimed in claim 36, characterized as follows: A module which adjusts the service carrier, including: a module which ceases transmission of data on MBMS services in accordance with the instruction; and/or a module which changes the service carrier mode in accordance with the instruction, and transmits data on MBMS services through the changed service carrier.