Background technology
Along with the 3G network commercialization at hand, mobile multi-media service also begins to get more and more people's extensive concerning as the characteristic service of 3G network.If characteristics such as mobile network's mobility, the property roamed are attached in the multimedia service of conventional fixed communication network, based on two net multimedia resources, develop comprehensive multimedia service, can bring bigger facility to the user undoubtedly.
But mainly by Internet Protocol (IP) carrying, the procotol of use comprises the multimedia service of fixed communication network: H.323 agreement, session initiation protocol (SIP), real time streaming protocol (rtsp).Wherein, being most widely used of agreement H.323.And the procotol that the 3G multimedia service adopts is agreement H.324M therefore, to need finish the intercommunication of controlling signaling and multi-medium data between two nets by video gateway (VIG, Video Gateway), to realize described comprehensive multimedia service usually.
Fig. 1 has shown that 3G network and fixed communication network realize the network diagram of two net interconnectings by VIG.Wherein, mobile switching centre (MSC) and RNS (RNS) that 3G network comprises attaching position register (HLR), is made of Media Gateway Controller (MGC) and media gateway (MG), wherein, message transmitted will be carried by IP between MGC and MG.
Typical fixed communication network will comprise Media Resource Server (MRS, Multimedia ResourceServer).In the application of Ring Back Tone service, MRS will use as the multimedia color ring back tone platform.
As shown in Figure 1, by VIG equipment is set, can realize the multimedia interconnection of 3G network and fixed communication network in 3G network and fixed communication network.Wherein, the MG in the 3G network communicates by IP or time-multiplexed E1 mode and VIG equipment, the network element in VIG equipment and the fixed communication network, and for example MRS communicates by the IP mode.
In the network shown in fig. 1, when the MSC of 3G network detects the calling of being initiated by the 3G portable terminal is multimedia service calling, and in the time of this call proceeding need being arrived fixed communication network, MSC arrives VIG equipment with this call proceeding, VIG is behind the capability negotiation of finishing respectively with fixed communication network and 3G portable terminal, fixed communication network is arrived in call proceeding, and in calling procedure, finish H.324M agreement to agreement H.323, the conversion of SIP or RTSP agreement realizes the multimedia interconnection between 3G network and the fixed communication network.
Though above-mentioned this method has solved the problem of multimedia interconnection between 3G network and the fixed communication network, can realize the comprehensive multimedia service of two nets, also there is following problem:
1, the method for above-mentioned realization 3G network and fixed communication net interconnecting need be provided with VIG equipment between two networks, thereby causes investment and operation, maintenance cost higher;
2, for some special business Multimedia Ring Back Tone service for example, when the mobile subscriber calls out the mobile subscriber who has customized Ring Back Tone service, MSC need at first route the call to VIG, again by the intercommunication of VIG realization with the multimedia color ring back tone platform, thereby be calling subscriber's coloring ring back tone playing, and after caller and called users is connected, though do not needed VIG at calling procedure, but VIG will exist as the relaying of calling out always, thereby, cause to call out to have alternate route, and can take the resource of VIG, cause the wasting of resources;
3, in said process, VIG can be earlier and MRS carry out capability negotiation, and then carry out capability negotiation with 3 G portable terminals, in this case, if twice negotiation result is inconsistent, VIG carries out capability negotiation with MRS again with regard to needs, thereby causes the call flows complexity; Yet, if MRS do not support to consult again, need VIG at first to finish capability negotiation with the 3G portable terminal, still, this situation can cause the charging of MSC mistake to occur usually.
Summary of the invention
In order to solve the problems of the technologies described above, the invention provides a kind of mobile switching centre of built in video gateway, finish the mutual of 3G network and fixed communication network by this mobile switching centre, realize multimedia business intercommunication between two nets.
The present invention also provides a kind of method that realizes multimedia interconnection between 3G network and fixed communication network, can avoid the alternate route that occurs in the calling procedure, and conserve system resources simultaneously improves the communication quality of multimedia service.
The mobile switching centre of built in video gateway of the present invention comprises: media gateway and Media Gateway Controller two parts; Described media gateway is built-in with and realizes multimedia interconnection video gateway unit between third generation network and the fixed communication network, this video gateway unit will be decomposed into H.245 signaling, audio stream and video flowing from the H.324M multimedia data stream of 3G portable terminal, H.245 signaling is wherein sent to Media Gateway Controller, wherein audio stream and video flowing sent to fixed communication network; Be used for simultaneously and will become H.324M that multimedia data stream sends to the 3G portable terminal from the H.245 signaling of Media Gateway Controller and from the audio stream of fixed communication network and video flowing are multiplexing.
Video gateway of the present invention unit comprises: end points T1, audio endpoint Ra, video endpoint Rb and Multiplexing module Mux;
Wherein, end points T1 is used for transmitting H.324M multimedia data stream between 3G portable terminal and Multiplexing module;
Multiplexing module Mux is used for the H.324M multimedia data stream from end points T1 is decomposed into H.245 signaling, audio stream and video flowing, and H.245 signaling sends to Media Gateway Controller, audio stream and video flowing are sent to audio endpoint Ra and video endpoint Rb respectively, be used for simultaneously sending to end points T1 with from the audio stream of audio endpoint Ra, become H.324M multimedia data stream from the video flowing of video endpoint Rb and from the H.245 signal multiplex of Media Gateway Controller;
Audio endpoint Ra is used for transmitting audio stream between Multiplexing module Mux and fixed communication network;
Video endpoint Rb is used for transmitting video flowing between Multiplexing module Mux and fixed communication network.
The method of realization multimedia interconnection of the present invention comprises:
A, portable terminal make a call, after the mobile switching centre that starts that is built-in with the video gateway unit detected and this call proceeding need be arrived fixed communication network multimedia service network element, making its built-in video gateway unit was this call distribution Multiplexing module, audio endpoint and video endpoint;
B, the described mobile switching centre that starts carry out capability negotiation with portable terminal and fixed communication network multimedia service network element respectively;
After c, capability negotiation were finished, portable terminal and described fixed communication network multimedia service network element carried out multimedia communication by Multiplexing module, audio endpoint and the video endpoint that is distributed by the built-in video gateway unit of the mobile switching centre that starts.
The mobile switching centre that starts of the present invention comprises media gateway and Media Gateway Controller, and wherein said media gateway is built-in with described video gateway unit;
Step a is described to be that this call distribution Multiplexing module, audio endpoint and video endpoint comprise:
A1, Media Gateway Controller are this call distribution Multiplexing module, audio endpoint and video endpoint by H.248 message built-in video gateway unit requests in media gateway of standard;
Built-in video gateway unit is this call distribution Multiplexing module, audio endpoint and video endpoint in a2, the media gateway, and by response message return distribute the Session Description Protocol attribute of Multiplexing module and audio endpoint, video endpoint to Media Gateway Controller.
Step b is described, and start mobile switching centre and portable terminal carries out capability negotiation and comprises:
B11, mobile terminal reporting self multimedia tenability are to Media Gateway Controller, the mobile switching centre that starts distributes corresponding resource according to the ability of mobile terminal reporting and the multimedia tenability of self, and to the multimedia tenability of portable terminal feedback self;
B12, portable terminal and the mobile switching centre that starts consult this calling procedure sound intermediate frequency stream and the multiplexing rule of video flowing and relevant parameter;
B13, portable terminal and the mobile switching centre that starts distribute corresponding logic channel according to the multiplexing rule of described audio stream of step b12 and video flowing for the audio stream and the video flowing of this calling.
The described multimedia tenability of step b11 is by the terminal capabilities set message bearing of signaling H.245;
The multiplexing rule of described audio stream of step b12 and video flowing is by H.245 principal and subordinate's decision message carrying of signaling;
The described assignment logic channel of step b13 is realized by the logic channel message of opening of signaling H.245.
Step b is described, and start mobile switching centre and portable terminal carries out capability negotiation and comprises:
The H.245 signal multiplex that portable terminal will comprise described terminal capabilities set message, principal and subordinate's decision message or open logic channel message is in multimedia data stream H.324M, send to the Multiplexing module of media gateway, described Multiplexing module demultiplexing from multimedia data stream H.324M goes out H.245 signaling, sends to Media Gateway Controller;
Media Gateway Controller sends to the Multiplexing module of media gateway by the H.245 signaling that will comprise capability set message, principal and subordinate's decision message or open logic channel message, described Multiplexing module in multimedia data stream H.324M, sends to described portable terminal with the H.245 signal multiplex that received.
Step b is described, and start mobile switching centre and fixed communication network multimedia terminal carried out capability negotiation and is:
B21, the mobile switching centre that starts send invitation message to fixed communication network multimedia service network element, and in this message, carry and be the audio endpoint of this call distribution and the Session Description Protocol attribute of video endpoint, notify the described fixed communication network multimedia service network element Voice ﹠ Video resource of mobile switching centre that start for this call distribution;
After b22, described fixed communication network multimedia service network element knew that the mobile switching centre that starts is for the audio frequency of this call distribution, video resource, response 180 and 200 message finished described capability negotiation process.
Multiplexing module, audio endpoint and video endpoint that described portable terminal of step c and described fixed communication network multimedia service network element distribute by the mobile switching centre that starts carry out multimedia communication and comprise:
The Multiplexing module of mobile switching centre of starting will be H.245 signaling, audio stream and video flowing from the H.324M multimedia data stream demultiplexing of portable terminal, and wherein audio stream and video flowing sent to described fixed communication network multimedia service network element by audio endpoint and video endpoint respectively;
The Multiplexing module of mobile switching centre of starting will receive by audio endpoint and video end office (EO), audio stream and video flowing from described fixed communication network multimedia service network element, reaching the H.245 signal multiplex that self produces becomes H.324M multimedia data stream, sends to described portable terminal.
Fixed communication network multimedia service network element of the present invention is: multimedia resource server, multimedia color ring back tone platform or fixed communication network multimedia terminal.
Method of the present invention can realize the intercommunication of two net multimedia services by in mobile switching centre's built in video gateway function between 3G network and fixed communication network; And compare with the method for existing external VIG equipment, because the video gateway function is built among the MSC, therefore, do not need to increase extra networking and operation maintenance cost, and,, adopt the MSC of built in video gateway not have alternate route to the particular service of for example Ring Back Tone service, thereby conserve system resources greatly improves the communication quality of multimedia service simultaneously.
Embodiment
In order to solve the problem that prior art exists, core concept of the present invention is, in the inner built-in VIG of MSC unit, realizes the function of VIG, thereby can be directly by the multimedia interconnection between MSC realization 3G network and the fixed communication network.
For this reason, the invention provides the MSC of a kind of built-in VIG, this MSC comprises the MG that is responsible for the adaptive conversion of media formats between the heterogeneous networks and MGC two parts of realizing all controlled function, and wherein, MG further comprises the VIG unit that is used to realize multimedia interconnection between 3G network and the fixed communication network.
The internal structure of this VIG unit mainly comprises as shown in Figure 2: end points T1, audio endpoint Ra, video endpoint Rb and Multiplexing module Mux.Wherein, end points T1 is used to receive the H.324M multimedia data stream from the 3G portable terminal on the one hand, and with this H.324M multimedia data stream send to Multiplexing module Mux, be used on the other hand and will mail to the 3G portable terminal by RNS by the multiplexing synthetic H.324M multimedia data stream of Multiplexing module Mux; Multiplexing module Mux is used for the H.324M multimedia data stream from end points T1 is decomposed into H.245 signaling, audio stream and video flowing on the one hand, and H.245 signaling sends to MGC, audio stream and video flowing are sent to audio endpoint Ra and video endpoint Rb respectively, be used on the other hand from the audio stream of audio endpoint Ra, become H.324M multimedia data stream, and send to end points T1 from the video flowing of video endpoint Rb and from the H.245 signal multiplex of MGC; Audio endpoint Ra is used for transmitting audio stream between Multiplexing module Mux and fixed communication network; Video endpoint Rb is used for transmitting video flowing between Multiplexing module Mux and fixed communication network.
The MSC that is built-in with above-mentioned VIG unit on the one hand can will be H.245 signaling, audio stream and video flowing from the H.324M multimedia data stream demultiplexing of 3G portable terminal, and audio stream and video flowing sent to fixed communication network, on the other hand can also be with audio stream and the multiplexing H.324M multimedia data stream that becomes of video flowing from fixed communication network, send to corresponding 3G portable terminal, thereby can realize the multimedia interconnection between 3G network and the fixed communication network.
And, because MSC of the present invention is built-in with the VIG unit, can realize the VIG function in the inside of MSC, therefore, compare with the method for external VIG in the prior art, can reduce networking and operation and maintenance cost, and for particular services such as for example multimedia color ring back tones, there is not alternate route in its calling procedure, thereby can additionally not take the resource of MSC yet.
To utilize the MSC of built-in VIG function to realize the 3G network and the method for network multimedia intercommunication H.323 by specific embodiment explanation below.Fig. 3 has shown that MRS in 3G portable terminal and the fixed communication network carries out the idiographic flow of multimedia interconnection, may further comprise the steps:
A1:3G portable terminal (MS) sends the MGC of SETUP (foundation) message to MSC when making a call;
A2:MGC goes out this calling according to the SETUP message detection that receives and is multimedia call, and analyze should be with call proceeding behind the MRS of fixed communication network, by the standard Add (Mux of agreement H.248, Ra, Rb) message (increasing end points message) is distributed Multiplexing module Mux, audio endpoint Ra and video endpoint Rb to the built-in VIG request of MG for this multimedia call;
Wherein, (Rb) Mux, Ra in the message bracket and Rb are the entrained parameter of described increase end points message to Add for Mux, Ra;
A3:MG by standard H.248 the Add-Ack of agreement (Rb) message (increase end points response message) is returned by described built-in VIG and is distributed Session Description Protocol (SDP) attribute of Multiplexing module Mux and audio endpoint Ra, video endpoint Rb to MGC for Mux, Ra;
(Rb) message is that the Multiplexing module Mux of this call distribution and the SDP attribute of audio endpoint Ra, video endpoint Rb send to MGC by the Mux in the bracket, Ra and Rb parameter with MG to above-mentioned Add-Ack for Mux, Ra;
A4:MGC sends INVITE (invitation) message to MRS, and carries the SDP attribute of audio endpoint Ra and video endpoint Rb in this message, will inform MRS from the resource as this call distribution, carries out capability negotiation with MRS;
After A5~A7:MRS was known the resource allocation conditions of this calling, response 180 (rings) and 200 (called party answer) message were to MGC, and next MGC sends Connect (connection) message to MS, and instruct MS MRS replys, and this calling is set up;
A8~A10:MS start and MGC between H.324M capability negotiation handling process, by TCS (terminal capabilities set) message in the signaling H.245, MSD (principal and subordinate's decision) message and OLC (opening logic channel) message and MGC carry out capability negotiation;
Need to prove, in this step, described TCS, MSD and OLC message all are multiplexing H.245 signalings in described H.324M multimedia data stream, because VIG function that the MG in the present embodiment is built-in, therefore, MG calls out the Multiplexing Unit Mux that is distributed for this can go out H.245 signaling message by demultiplexing from described H.324M multimedia data stream, and these signaling messages are sent to MGC, finishes described capability negotiation process;
Described capability negotiation process specifically comprises:
At first, the ability that MS supports by TCS information reporting portable terminal self Voice ﹠ Video in the signaling message H.245, ability that MGC reports according to MS and the corresponding resource of self supporting of capability distribution are fed back the Voice ﹠ Video tenability of this MGC itself again to portable terminal by the TCS message in the signaling message H.245;
Then, MS and MGC consult H.324M multiplexing rule and other relevant parameters of multimedia data stream sound intermediate frequency stream and video flowing by the MSD message in the signaling message H.245 again, for example the code encoding/decoding mode that is adopted etc.; Described multiplexing rule promptly be H.324M in the multimedia data stream which logic channel carrying be audio stream, which logic channel carrying be video flowing;
At last, MS and MGC are the corresponding logic channel of this call distribution by the OLC message in the signaling message H.245;
In this step, if the result of this capability negotiation is consistent with the capability negotiation result of MRS with MGC, then directly carry out the multimedia communication process, if and negotiation result is inconsistent, then need by between Multiplexing module Mux, the audio endpoint Ra of MG and video endpoint Rb, inserting corresponding encoding and decoding conversion resource TC, finish the conversion of Streaming Media coding, realize the adaptive of multimedia tenability between MS and the MRS;
In the described capability negotiation process of above-mentioned A4~A10, MGC also can at first carry out capability negotiation with MS, carries out capability negotiation according to negotiation result and MRS again, and can not exceed the scope that this invention is intended to protect, in this case, the inconsistent situation of negotiation result can not appear;
A11: after capability negotiation was finished, MS and MRS carried out the multimedia communication process;
Before carrying out the multimedia conversation, MGC has been known the multiplexing rule of described H.324M multimedia data stream sound intermediate frequency stream and video flowing according to the MSD message of transmitting in the negotiations process, like this, in the multimedia communication process, Multiplexing module Mux among the configuration MG will resolve into audio stream and video flowing from the H.324M multimedia data stream of MS according to described multiplexing rule, and send to MRS by audio endpoint Ra and the video endpoint Rb that distributes among the MG, or will be from MRS, audio stream and the multiplexing H.324M multimedia data stream that becomes of video flowing by audio endpoint Ra and video endpoint Rb reception, send to MS, thereby realize the multimedia interconnection between MS and the MRS;
A12~A15: when this end of conversation, MS closes the logic channel that this multimedia communication is set up by CLC (closing logic channel) message request MGC, sends REL (release) message then and carries out normal call-closure flow process to MGC; MGC and MRS finish this multimedia call by BYE (goodbye) message and response message 200.
In above-mentioned steps, CLC message also is multiplexing H.245 signaling in described H.324M multimedia data stream, therefore, also needs the Multiplexing Unit Mux among the MG that described H.324M multimedia data stream is carried out demultiplexing, just can obtain described CLC message.
Because the described method of present embodiment has realized the function of VIG in the inside of MG, therefore, MSC does not need and external VIG carries out just can realizing alternately and fixed communication network between multimedia interconnection, the construction and the operation maintenance cost of having saved network greatly; In addition, because MG can insert corresponding TC between Multiplexing module Mux, audio endpoint Ra and video endpoint Rb, carry out transcoding, coding transform, therefore, MSC and MRS and with the inconsistent situation of the capability negotiation of MS under still can realize multimedia interconnection, and do not need negotiations process again, and simplified the handling process of MGC greatly, also can avoid simultaneously the problem of the MSC billing error that occurs in the existing method.
The foregoing description only is the method for carrying out multimedia interconnection with 3G portable terminal and fixed communication network MRS, use said method MS can also with fixed communication network in can carry out capability negotiation fixed communication network multimedia service network element directly carry out multimedia interconnection.H.323 or the multimedia terminal of other fixed communication networks for example, described fixed communication network multimedia service network element can be.
Utilize the MSC of built-in VIG function to realize the method for Multimedia Ring Back Tone service by the specific embodiment explanation more below, in the present embodiment, portable terminal will carry out the multimedia interconnection process with the multimedia color ring back tone platform (MRBT) as fixed communication network multimedia service network element, as shown in Figure 4:
B1: when the portable terminal that starts (MO) was initiated multimedia call, MO sent SETUP message to originating MS C (O_MSC);
The originating terminal of described MO for calling out can be the 3G portable terminal that makes a call;
B2:O_MSC knows that the called subscriber also for behind the mobile subscriber, asks for called subscriber's roaming number to HLR;
In this step, O_MSC will be by the roaming number of SRI (transmission routing iinformation) message to HLR request called subscriber, the reciprocal process that HLR responds by PRN (Providing Roaming Number) and PRN obtains called subscriber's roaming number, and the roaming number that responds the called subscriber by SRI sends to O_MSC again;
B3:O_MSC knows that in the process of asking for called subscriber's roaming number the called subscriber has contracted behind the Multimedia Ring Back Tone service, is this call distribution Multiplexing module Mux, audio endpoint Ra and video endpoint Rb;
In this step, O_MSC also is divided into MGC and MG two parts, and described distribution Multiplexing module Mux, the method of audio endpoint Ra and video endpoint Rb is identical with the described method of steps A 2~A3, the MGC that is O_MSC is by Add (Mux, Ra, Rb) message is distributed Multiplexing module Mux, audio endpoint Ra and video endpoint Rb to the built-in VIG request of MG for this multimedia call, MG is by Add-Ack (Mux, Ra, Rb) message is returned the SDP attribute that is distributed Multiplexing module Mux and audio endpoint Ra, video endpoint Rb by built-in VIG;
B4~B6:O_MSC arrives called mobile terminal (MT) according to called subscriber's roaming number with call proceeding, and after the MT ring and returning ACM (address is complete) message, carries out capability negotiation with MO and MRBT respectively;
Described O_MSC and MO reach the capability negotiation process of carrying out with MRBT and can realize by following dual mode:
First kind: at first carry out capability negotiation, carry out capability negotiation with MRBT again with MO;
Second kind: at first carry out capability negotiation, carry out capability negotiation with MO again with MRBT;
Wherein, O_MSC is identical with the described capability negotiation method of steps A 7~A10 with the method that MO carries out capability negotiation; O_MSC is identical with the described capability negotiation method of steps A 4~A6 with the method that MRBT carries out capability negotiation;
In the capability negotiation process of MO and O_MSC, MO is by the TCS information reporting portable terminal tenability in the signaling message H.245, and O_MSC is the Voice ﹠ Video tenability by the TCS message informing portable terminal O_MSC itself in the signaling message H.245 also; MO and O_MSC consult the H.324M multiplexing rule of multimedia data stream sound intermediate frequency stream and video flowing by the MSD message in the signaling message H.245;
B7:MRBT is a MO play multimedia CRBT;
In this step, MRBT is MO play multimedia CRBT by O_MSC for Multiplexing module Mux, audio endpoint Ra and the video endpoint Rb of this call distribution, the Multiplexing module Mux that is O_MSC will re-send to described MO from audio stream and the multiplexing H.324M multimedia data stream that becomes of video flowing of MRBT.At this moment, MO just can see the multimedia video image that Multimedia Ring Back Tone service provides, and hears multimedia audio sound;
B8~B11: when MT replied, O_MSC removed the connection of O_MSC to MRBT;
In this step, when MT replys, MT will send Connect message to T MSC, T_MSC sends ANM (replying) message to O MSC, and notice O_MSC called subscriber replys, at this moment, O_MSC and MRBT remove the connection of O_MSC to MRBT by BYE (goodbye) and response message 200;
B12:O_MSC and MT carry out capability negotiation, if this capability negotiation result is consistent with the capability negotiation result of MO with O_MSC, then delete Multiplexing module Mux, audio endpoint Ra and video endpoint Rb that O_MSC sets up at step B3, otherwise, between Multiplexing module Mux, audio endpoint Ra and video endpoint Rb, insert corresponding TC, carry out code conversion;
In this step, it is identical with the described capability negotiation process of steps A 7~A10 that O_MSC and MT carry out the capability negotiation process, the purpose of carrying out capability negotiation with MT is, knows audio frequency and the video tenability of MT, is convenient to media gateway and finishes Streaming Media conversion between MO and the MT;
Under the consistent situation of the capability negotiation result of O_MSC and MT and MO, owing to do not need Multiplexing module Mux, audio endpoint Ra and video endpoint Rb to carry out code conversion, therefore, in order to save resource, avoid communication quality to sustain damage, should delete Multiplexing module Mux, audio endpoint Ra and video endpoint Rb that O_MSC sets up at step B3;
B13~B15:MO and MT converse, and behind end of conversation, O_MSC sends REL (release) message to T_MSC, and T_MSC sends RLC (release is finished) message to O_MSC, discharge the link that this multimedia conversation is set up.
From said process as can be seen, the described method of present embodiment can realize the multimedia interconnection between 3G network and the fixed communication network by realized the function of VIG in MG inside.In addition, because video gateway is built in MSC, under the O_MSC situation consistent with the capability negotiation result of MT and MO, do not need Multiplexing module Mux, audio endpoint Ra and video endpoint Rb to carry out code conversion, make calling procedure not have alternate route, thereby avoided the waste of resource effectively, simultaneously owing to do not exist alternate route can also improve the communication quality of multimedia service between the portable terminal.