Background technology
Extensive use along with the flourish and wireless network of internet service; Mobile subscriber's number rapidly increases; Thereupon; User's demand also improves rapidly, and this requires wireless technology undoubtedly, like GPRS (General Packet Radio Service GPRS), 3G, WiMAX and B3G (Beyond 3G; Back 3G) etc. wireless technology can be supported big capacity, the multiple business that big data quantity and different service quality require.
Wireless access technology is as the bridge between wireless user and existing cable network or other business networks, mainly accomplishes that the Packet Service that provides between network and the mobile subscriber is transmitted or the function of route.
Be example with WiMAX network architecture system as shown in Figure 1 below, the function of each network element in the WiMAX wireless access system that adopts wireless access technology be described:
In Fig. 1, said WiMAX wireless access system comprises MSS (Mobile Subscribe Station mobile subscriber station), ASN (Access Service Network; Access service network) and CSN (Connectivity Service Network; Connectivity serving network).
Wherein, said MSS is a mobile subscriber terminal equipment, and the user uses this devices accessing WiMAX network.
Wherein, said ASN comprises BS (Base Station; The base station) and ASN-GW (Access Service Network GateWay; Access service network gateway) etc., be used to the network function set that the WiMAX terminal equipment provides the wireless access service.As, the functions such as compression and encryption of being connected of BS and MSS, RRM, measurement and power control, the data of eating dishes without rice or wine are provided based on said BS; Based on said ASN-GW, for MSS authentication function provides the proxy function, supports the network of NSP to find and select, provide for MSS the functions such as Relay function (like IP address assignment), RRM of L3 information.
Wherein, said CSN is used to the WiMAX terminal IP is provided Connection Service.As; For MSS distributing IP address, provide Internet to insert, AAA proxy or server are provided, authorization control based on the user is provided, ASN be provided the tunnel to CSN; Be equivalent to the tunnel between the CSN, the switching between the different ASN under the HA (home agent) in the mobile IP technology, the charging that WiMAX user is provided and the clearing between the operator, the roaming condition, and various WiMAX service (like location-based business, multi-medium multi-packet broadcasting and broadcasting service, IP Multimedia System business) etc.
Still combine Fig. 1 to describe the process of transfer of data between each network element below:
The grouping busihess data message of descending MSS is through HA among the CSN and the Interface R3 between the ASN-GW among the ASN; Be sent to the ASN from the HA of CSN; And by the ASN-GW of ASN-GW process ASN inside and the R6 interface between the BS, and the R1 interface between BS and the MSS sends to the MSS data on the MSS.
Can find out by Fig. 1, along with moving of mobile subscriber, the access device between user and the ASN; Like the BS among Fig. 1; And all might change with ASN-GW between this user-dependent access network and the business network (also being core network, like the CSN among Fig. 1), switching has just taken place.
Under the situation that ASN-GW changes; Possibly exist some to send to the downlink grouped data message on the original ASN-GW; If take these grouped data report are all abandoned this moment; Guarantee that through the retransmission mechanism of waiting for the upper strata these grouped data report send to the method for the mobile phone users of MSS through new BS then; Then need transmitting terminal mobile subscriber and receiving terminal mobile subscriber to participate in simultaneously and could realize, therefore will cause than higher packet loss and long professional propagation delay time.
In order to reduce packet loss and traffic transmission time delay, each wireless system has all been taked the corresponding techniques strategy.
The technical scheme of the prior art one relevant with the present invention:
In ASN-GW, for each BS under the corresponding scope with it formation is set all, be used to store do not have relevant and send or do not receive the business (frame) of affirmation with MSS.When Intra ASN-GW switching takes place when; Be that the target BS that switches to of MSS and source BS are in same ASN-GW control range the time; Said ASN-GW at first finds the formation of the BS corresponding with it; Then that send and that the do not receive affirmation business (frame) relevant with this MSS in it deleted, and, perhaps directly said business (frame) is transferred to the formation of corresponding new BS through on CSN, adopting the harmless transmission of retransmission mechanism assurance end to end professional (frame).
Yet in the switching that Inter ASN-GW takes place; Be the target BS that switches to of MSS and source BS not in same ASN-GW control range the time, send and unacknowledged frame can not shift, therefore; Must wait for when the mobile subscriber is in a certain position; Rebulid being connected of data surface of new ASN-GW and CSN, then all data messages directly are dealt on the new ASN-GW from CSN, transmit or be routed to the mobile subscriber through new BS at last.
Technical scheme by above-mentioned prior art one can be found out:
1, the method that the not transmission in the formation and unacknowledged business (frame) are directly deleted of above-mentioned employing causes packet loss than higher when ASN-GW switches.Even on CSN, adopt retransmission mechanism end to end, also can cause excessive time delay expense, and accordingly for supporting to retransmit system signaling and the data transfer overhead that increases.
2, the method for the formation of said business (frame) being transferred to corresponding new BS of above-mentioned employing; Though can guarantee less packet loss; But no matter whether can switch; In ASN-GW, all a formation buffered packet business datum message to each BS must be set, therefore this method requires ASN-GW to have bigger memory space when traffic carrying capacity is bigger.
3, prior art one has changed the be connected link of ASN-GW with CSN, has increased the signaling exchange expense between ASN-GW and CSN.
The technical scheme of the prior art two relevant with the present invention:
Pass through ASN-GW; A buffering area is set on each mobile subscriber's Packet Service passage; Distribute a unique sequence number corresponding for the grouped data report that sends over from CSN simultaneously, be used for indicating a copy of this data message that is stored at present among the CSN with CSN.
When the mobile subscriber switches; The data message that has received for ASN-GW; If also not through send or also do not receive the affirmation information of bringing in from the user from ASN-GW; Then need all the data deletions in the buffering area perhaps be handled according to condition of different through source ASN-GW, Intra ASN-GW switches to take place below, Inter ASN-GW switches to the concrete processing procedure of example explanation:
If Intra ASN-GW switches, then ASN-GW does not change, this moment directly from the ASN-GW of source, but pass through the new BS that it manages and send to the mobile subscriber also not sending or sent the downlink business frame that not have to confirm.
If Inter ASN-GW switches; Then at first under the situation that is connected link that does not change between ASN and CSN; Set up the data channel between a new ASN-GW and the source ASN-GW; Then through this newly-built data channel, all data that are stored in the buffering area of source ASN-GW are sent among the new ASN-GW, last new ASN-GW sends to the mobile subscriber through new BS with said data message.
Technical scheme by above-mentioned prior art two can be found out:
1, prior art two need be set up the mechanism that storage is transmitted at the CSN end; Therefore will increase the burden of CSN; And under the situation of complete IP network, need CSN some router relevant with ASN to have the memory space of larger capacity, the large user measures to deal with, the requirement of big data quantity.Again the content of transmitting all need send to new ASN-GW from CSN, has increased internetwork flow, has increased network overheads such as signaling and data.
2, prior art two exists and prior art one similar problem equally: spatial cache cancels perhaps switching among other ASN-GW serving just necessary at first foundation up to mobile subscriber's service, therefore require ASN-GW to have bigger memory space.
3, for sending among the BS but not sending to data on the MSS can only take the method that abandons when switching, so the packet loss of data is than higher.
Embodiment
The embodiment of the invention provides and can't harm the method for switching in a kind of wireless access technology; When switching; Through the data channel between source network element and target network element; Give corresponding target network element with the data message forwarding of the mobile subscriber station MSS of giving to be sent that is buffered in the source network element, and the connectivity serving network CSN that passes through to set up will send said target network element to from the data message that sends to MSS that CSN transmits to the data channel between target network element; Further, said target network element can send the data message that receives to corresponding MSS.
First embodiment provided by the invention, as shown in Figure 2, comprising:
Step 101, in said source ASN-GW, set up buffer.
This process specifically comprises two kinds of situation.
One of which is: according to the qos requirement of business and/or user's grade, static state is set up buffer in said source ASN-GW.
It two is: when ASN-GW taking place switch, according to the qos requirement of business and/or user's grade, in said source ASN-GW, dynamically set up buffer.This process specifically comprises:
Step 1, source BS and MSS consult to trigger when switching, and switch message informing source ASN-GW through sending;
Step 2, when said source ASN-GW receives said switching message, according to the qos requirement of said business and/or user's grade, in said source ASN-GW, dynamically set up buffer.
BS moves to the scope that target BS covers from the source at MSS, perhaps in the scope that source BS and target BS are covered simultaneously, has been triggered when switching by MSS or network side; Source ASN-GW will be through for the qos requirement of business and/or user's grade; Whether decision need adopt buffer mechanism to support the harmless switching of Packet Service; If desired; Then in the ASN-GW of source, dynamically set up a buffer to this MSS, the downlink data newspaper of this MSS that all tunnels between CSN process CSN and ASN-GW send over will be buffered in the said buffer; Confirm the parameter of buffer simultaneously according to qos requirement.
Step 102, send to the downlink data message of MSS through said buffer buffer memory.
Under normal circumstances, source BS sends to the part downlink data message of MSS according to the actual conditions buffer memory.BS moves to the scope that target BS covers from the source at MSS; Perhaps in the scope that source BS and target BS are covered simultaneously; When having triggered switching by MSS or network side; Said source ASN-GW launches buffer mechanism: source ASN-GW no longer sends the downlink data packet of this MSS to source BS, the MSS data message that the buffer buffer memory through said foundation transmits from CSN.
Step 103, in when, ASN-GW taking place switching when; CSN through setting up arrives the data channel between target ASN-GW; Send the data message of the MSS that sends to said target ASN-GW, and said data in buffer message is sent to target ASN-GW through the data channel between source ASN-GW and said target ASN-GW.
The process of step 103 specifically comprises following two kinds of situation.
One of which is: when the ASN-GW switching takes place; After source ASN-GW and target ASN-GW consult; Target ASN-GW notice CSN sets up said CSN to the data channel between target ASN-GW, and through said newly-built data channel, sends the data message that sends to MSS to said target ASN-GW; Simultaneously, target ASN-GW notification source ASN-GW sets up source ASN-GW to the data channel between target ASN-GW, and notification source ASN-GW sends to target ASN-GW with the data in buffer message through said data channel.
This process is switched to Inter ASN-GW; At first as shown in Figure 3; Target ASN-GW notice CSN sets up CSN to the R3 data channel between the target ASN-GW, and target ASN-GW notification source ASN-GW sets up source ASN-GW to the R4 data channel between target ASN-GW simultaneously;
Then, through said newly-built R3 data channel, send the data message that sends to MSS to said target ASN-GW; Through said newly-built R4 data channel, the data message that is buffered among the ASN-GW of source is sent to target ASN-GW.
It two is: when the ASN-GW migration takes place; After source ASN-GW or target ASN-GW trigger the data channel of decision change from CSN to source ASN-GW; By the newly-built data channel of said target ASN-GW notice CSN from CSN ASN-GW to the source; And, send the data message that sends to MSS to said target ASN-GW through said newly-built data channel; Simultaneously, said source ASN-GW sends to the data in buffer message among the target ASN-GW through the data channel between said source ASN-GW and target ASN-GW.
The situation that this process is moved to ASN-GW: promptly be directed against as shown in Figure 4; MSS has switched; And ASN-GW, target ASN-GW and target BS need to change the R3 passage to the passage of MSS through the source to have set up CSN, make data channel become CSN arrives MSS through target ASN-GW and target BS passage; This situation can be called the ASN-GW migration; When the ASN-GW migration takes place, after source ASN-GW or target ASN-GW trigger the data channel of decision change from CSN to source ASN-GW, by the newly-built R3 data channel from CSN ASN-GW to the source as shown in Figure 4 of said target ASN-GW notice CSN.Keep the R4 data channel between original source ASN-GW and target ASN-GW simultaneously.
Then, through said newly-built R3 data channel, send the data message that sends to MSS to said target ASN-GW; Through the R4 data channel of said maintenance, the data message that is buffered among the ASN-GW of source is sent to target ASN-GW.
Step 104, said target ASN-GW send the data message that receives to corresponding MSS.
Said target ASN-GW receives the MSS downlink data message that sends from said CSN, and the data message that sends over from said source ASN-GW; Then said data message is sent to said target BS through the data channel between said target ASN-GW and said target BS; Last said target BS sends to corresponding MSS with air interface between said MSS with said data message through it.
Step 105, after the data message in the buffer disposes; Discharge the buffer among the said source ASN-GW and discharge the data channel between said source ASN-GW and said target ASN-GW, and the downlink data message of the said MSS that sends from CSN that continues to receive of the data channel through said foundation sends to corresponding MSS.
Said step 105 specifically comprises:
Step 1, after the data message in the buffer disposes, discharge the buffer among the said source ASN-GW;
Step 2, from the downlink data message that CSN sends to the said MSS of source ASN-GW, send to target BS through the passage between said target ASN-GW and target BS;
Step 3, said target BS send among the MSS through the air interface between itself and MSS.
Second embodiment provided by the invention, as shown in Figure 5, comprising:
Step 201, according to the situation of utilizing of service dispatching strategy or interface-free resources, buffer memory waits to issue the data message among the MSS by said source BS in the BS of source.
Under normal circumstances; The downlink data newspaper of this MSS that sends over through the tunnel between CSN and the ASN-GW from CSN directly is forwarded to source BS through source ASN-GW; Send on the MSS through air interface through source BS; Because factors such as service dispatching and interface-free resources utilizations, the datagram that sends to this MSS among the BS of source might be by temporary cache.
For example, for the datagram of receiving from network terminal, if temporary transient interface-free resources is limited, the said data message of first buffer memory in the BS of source so just is up to there being certain interface-free resources can this datagram be sent to the MSS of appointment.Perhaps sometimes, for the datagram that some specific service quality requires, need in BS, take retransmission mechanism; After these data sent from BS, first buffer memory was up to the affirmation message of the correct reception of receiving this MSS; Just data in buffer is deleted; Source BS receives the Nack (affirmation failed message) that MSS beams back or behind certain hour, does not still receive any acknowledge message of MSS else if, just need data in buffer be retransmitted, up to receiving acknowledge message.
Step 202, in said source ASN-GW, set up buffer.With first embodiment, be not described in detail.
Step 203, send to the downlink data message of MSS through said buffer buffer memory.
The downlink data message that said buffer buffer memory sends to MSS comprises: the downlink data message of the MSS that from said CSN, sends over, and the data message that is transmitted to said source ASN-GW from said source BS.
Still be untreated the processing method of data message of this MSS according to corresponding tupe information decision the switching message between source ASN-GW and the source BS for what source BS received from source ASN-GW: abandon the data message among the BS of source or the data message transmitted among the BS of source returns source ASN-GW control.If select to abandon, source BS will directly abandon the datagram of untreated this MSS still of the transmission of the ASN-GW from the source of receiving so; Otherwise will these datagrams be transmitted back in the buffer among the ASN-GW of source again through the passage of source BS and source ASN-GW.
Said step 203 specifically comprises:
The MSS data message that step 1, the said source ASN-GW buffer buffer memory through said foundation transmits from CSN; Source ASN-GW is according to the resource usage degree and/or the user gradation of the data channel between QoS quality requirement, source BS and the source ASN-GW of the service of the user in the switching message between said source ASN-GW and the source BS; Notification source BS is discarded among the BS of source the data in buffer message or data in buffer message in the said source BS is transmitted back source ASN-GW control; When selecting to abandon; Then notify said source BS to abandon data in buffer message in it, finish this step then; When selecting to transmit, notify said source BS that data in buffer message in it is forwarded among the said source ASN-GW, execution in step two then;
Step 2, the said source BS data channel through setting up between itself and said source ASN-GW sends to said source ASN-GW with data in buffer message in it;
Step 3, said source ASN-GW are kept at the data message that receives in the buffer of said foundation.
Step 204, in when, ASN-GW taking place switching when; CSN through setting up arrives the data channel between target ASN-GW; Send the data message of the MSS that sends to said target ASN-GW, and said data in buffer message is sent to target ASN-GW through the data channel between source ASN-GW and said target ASN-GW.
The practical implementation process of said step 204 is described with the associated description among first embodiment here no longer in detail.
Step 205, said target ASN-GW send the data message that receives to corresponding MSS.
Said target ASN-GW receives the MSS downlink data message that sends from said CSN, and the data message that sends over from said source ASN-GW; Then said data message is sent to said target BS through the data channel between said target ASN-GW and said target BS; Last said target BS sends to corresponding MSS with air interface between said MSS with said data message through it.
The practical implementation process of said step 205 is described with the associated description among first embodiment here no longer in detail.
Step 206, after the data message in the buffer disposes; Discharge the buffer among the said source ASN-GW and discharge the data channel between said source ASN-GW and said target ASN-GW, and the downlink data message of the said MSS that sends from CSN that continues to receive of the data channel through said foundation sends to corresponding MSS.
The practical implementation process of said step 206 is described with the associated description among first embodiment here no longer in detail.
The 3rd embodiment provided by the invention; Be with the first embodiment difference; When the tunnel of CSN and ASN is based upon certain equipment among BS (replacing the function of ASN-GW as FA) and the CSN (like HA; The perhaps equipment of identity function) in the time of between, buffer can be placed on above the BS, is equivalent to the storage that BS accomplishes ASN-GW among part the present invention this moment and transmits the harmless function of switching.
The 3rd embodiment provided by the invention comprises:
Step 301, in said source BS, set up buffer.
This process specifically comprises two kinds of situation.
One of which is: according to the qos requirement of business and/or user's grade, static state is set up buffer in said source BS.
It two is: when switching, according to the qos requirement of business and/or user's grade, in said source BS, dynamically set up buffer.This process specifically comprises:
Step 1, source BS and MSS consult to trigger and switch;
Step 2, when said source BS and MSS consult to finish, according to the qos requirement of said business and/or user's grade, in said source BS, dynamically set up buffer.
BS moves to the scope that target BS covers from the source at MSS, perhaps in the scope that source BS and target BS are covered simultaneously, has been triggered when switching by MSS or network side; Source BS will be through for the qos requirement of business and/or user's grade; Whether decision need adopt buffer mechanism to support the harmless switching of Packet Service; If desired; Then in the BS of source, dynamically set up a buffer to this MSS, the downlink data newspaper of this MSS that all tunnels between CSN process CSN and BS send over will be buffered in the said buffer; Confirm the parameter of buffer simultaneously according to qos requirement.
Step 302, send to the downlink data message of MSS through said buffer buffer memory.
Under normal circumstances, source BS sends to the part downlink data message of MSS according to the actual conditions buffer memory.BS moves to the scope that target BS covers from the source at MSS; Perhaps in the scope that source BS and target BS are covered simultaneously; Triggered when switching by MSS or network side, said source BS launches buffer mechanism: the MSS data message that the buffer buffer memory through said foundation transmits from CSN.
Step 303, when switching; Through the CSN that sets up to the data channel between target BS; Send the data message of the MSS that sends to said target BS, and said data in buffer message is sent to target BS through the data channel between source BS and said target BS.
The process of step 303 specifically comprises following two kinds of situation.
One of which is: when switching, after source BS and target BS were consulted, target BS notice CSN set up said CSN to the data channel between target BS, and through said newly-built data channel, sends the data message that sends to MSS to said target BS; Simultaneously, target BS notification source BS sets up source BS to the data channel between target BS, and notification source BS sends to target BS with the data in buffer message through said data channel.
It two is: when migration takes place; After source BS or target BS trigger the data channel of decision change from CSN to source BS; By the newly-built data channel from CSN to the target BS of said target BS notice CSN; And, send the data message that sends to MSS to said target BS through said newly-built data channel; Simultaneously, said source BS sends to the data in buffer message in the target BS through the data channel between said source BS and target BS.
Step 304, said target BS send the data message that receives to corresponding MSS.
Said target BS receives the MSS downlink data message that sends from said CSN, and the data message that sends over from said source BS; Then with said data message through said target BS with said MSS between air interface said data message is sent to corresponding MSS.
Step 305, after the data message in the buffer disposes; Discharge the buffer among the said source BS and discharge the data channel between said source BS and said target BS, and the downlink data message of the said MSS that sends from CSN that continues to receive of the data channel through said foundation sends to corresponding MSS.
The 4th embodiment provided by the invention; Be with the difference of said second embodiment; When the tunnel of CSN and ASN is based upon certain equipment among BS (replacing the function of ASN-GW as FA) and the CSN (like HA; The perhaps equipment of identity function) in the time of between, buffer can be placed on above the BS, is equivalent to the storage that BS accomplishes ASN-GW among part the present invention this moment and transmits the harmless function of switching.Its practical implementation process comprises:
Step 401, according to the situation of utilizing of service dispatching strategy or interface-free resources, buffer memory waits to issue the data message among the MSS by said source BS in the BS of source.
Under normal circumstances; The downlink data newspaper of this MSS that sends over through the tunnel between CSN and the BS from CSN directly is forwarded to source BS; Send on the MSS through air interface through source BS; Because factors such as service dispatching and interface-free resources utilizations, the datagram that sends to this MSS among the BS of source might be by temporary cache.
For example, for the datagram of receiving from network terminal, if temporary transient interface-free resources is limited, the said data message of first buffer memory in the BS of source so just is up to there being certain interface-free resources can this datagram be sent to the MSS of appointment.Perhaps sometimes, for the datagram that some specific service quality requires, need in BS, take retransmission mechanism; After these data sent from BS, first buffer memory was up to the affirmation message of the correct reception of receiving this MSS; Just data in buffer is deleted; Source BS receives the Nack (affirmation failed message) that MSS beams back or behind certain hour, does not still receive any acknowledge message of MSS else if, just need data in buffer be retransmitted, up to receiving acknowledge message.
Step 402, in said source BS, set up buffer.Describe with the related content among the 3rd embodiment, be not described in detail.
Step 403, send to the downlink data message of MSS through said buffer buffer memory.
The downlink data message that said buffer buffer memory sends to MSS comprises: the downlink data message of the MSS that from said CSN, sends over, and the data message that from the BS buffer memory of said source, is uploaded to said source BS.
Treating method for from the BS buffer memory of said source, being uploaded to the data message of said source BS is:
When switching; The MSS data message that the buffer buffer memory of said source BS through said foundation transmits from CSN; And according to the handover management information of BS inside data in buffer message or data in buffer message in the said source BS is kept in the buffer of said foundation in decision is discarded among the BS of source; When selecting to abandon, then notify said source BS to abandon data in buffer message in it, finish this step then; When selecting to transmit, notify said source BS that data in buffer message in it is saved in it and switch in the buffer of setting up for harmless, said then source BS is kept at the data message that receives in the buffer of said foundation.
Step 404, when switching; Through the CSN that sets up to the data channel between target BS; Send the data message of the MSS that sends to said target BS, and data in buffer message in the said buffer is sent to target BS through the data channel between source BS and said target BS.
The practical implementation process of said step 404 is described with the associated description among the 3rd embodiment here no longer in detail.
Step 405, said target BS send the data message that receives to corresponding MSS.
Said target BS receives the MSS downlink data message that sends from said CSN, and the data message that sends over from said source BS; Then said data message is sent to corresponding MSS with air interface between said MSS with said data message through said target BS.
Step 406, after the data message in the buffer disposes; Discharge the buffer among the said source BS and discharge the data channel between said source BS and said target BS; And the downlink data message of the said MSS that sends from CSN that continues to receive to the data channel between target BS of the CSN through said foundation sends to target BS, through the air interface between the target BS set up and said MSS the downlink data message of said MSS sent to corresponding MSS then.
Below in conjunction with Fig. 6, MSS is triggered Inter ASN-GW switch, and the R4 data channel between source ASN-GW and target ASN-GW sets up failure for a long time, trigger the situation that the Interface R3 between CSN and ASN-GW moves and describe.
Under normal circumstances, source BS sends to the part downlink data message of MSS according to the actual conditions buffer memory; When source BS and MSS negotiation triggering switching, through the switching message informing source ASN-GW that sends.
Said source ASN-GW is during according to the data message of corresponding tupe information decision forwarding cache in the switching message between source ASN-GW and source BS in the BS of source; Then the R6 passage through setting up between source ASN-GW and source BS notifies said source BS that data in buffer message in it is transmitted back source ASN-GW control.
Said source BS to the passage between the ASN-GW of source, transmits back source ASN-GW with data in buffer message in it through source BS; Simultaneously, the downlink data message that from the HA of CSN, or has sent to all MSS of source ASN-GW all is saved in the buffer.
The relevant handover information of source ASN-GW and target ASN-GW exchange MSS is set up the R4 passage between target ASN-GW and source ASN-GW, and is set up the R6 passage between target ASN-GW and target BS, sets up the R1 passage of target BS and MSS.
When the R4 passage that can't set up for a long time between target ASN-GW and source ASN-GW; Perhaps because resource problem or target ASN-GW trigger when changing CSN to ASN-GW; Source ASN-GW/ target ASN-GW decision triggers the Interface R3 migration between CSN and ASN-GW: set up the R3 data channel between the HA of target ASN-GW and CSN; And will send to target ASN-GW from the MSS data message that CSN sends through newly-built R3 passage; Through the R4 passage between newly-built target ASN-GW and source ASN-GW, give corresponding target ASN-GW simultaneously with the data message forwarding among the said source ASN-GW.
Then, said target ASN-GW sends to said data message in the target BS through newly-built target ASN-GW and the R6 passage between target BS, is sent among the MSS through the air interface (newly-built R1 data channel) between itself and MSS by target BS at last.
After the data message in the buffer disposes, discharge the buffer among the said ASN-GW, and the R4 passage between newly-built target ASN-GW and source ASN-GW.
The downlink data message of the said MSS that sends from CSN; Said data message is sent in the target BS to the R6 passage between target BS through said newly-built source ASN-GW, send among the MSS through the air interface (newly-built R1 data channel) between itself and MSS at last by target BS.。
Below in conjunction with Fig. 7, after MSS triggering Inter ASN-GW switching, set up the R4 passage between target ASN-GW and source ASN-GW earlier, the situation that the Interface R3 migration between CSN and ASN-GW takes place again describes.
After source or target ASN-GW trigger the passage of decision this MSS of change from CSN to ASN; Then only need the HA among the target ASN-GW notice CSN to send among the target ASN-GW through HA and the passage of setting up between the target ASN-GW, utilize R6 and the R1 passage set up that data are sent on the MSS then all about the downlink data newspaper of this MSS.For the R4 passage; Consider to remain before the transmit path that still has the HA of the descending data of part in target ASN-GW notice CSN to change MSS downlink data newspaper to send to source ASN-GW, target ASN-GW notification source ASN-GW continue on Interface R4, to transmit receive the Interface R3 that passes through HA and source ASN-GW that comes data in target ASN-GW.After this close the R4 passage between source ASN-GW and the target ASN-GW.The practical implementation process is following:
Step 1, under normal circumstances; The downlink data of MSS is subject to the Interface R3 of crossing between HA and the source ASN-GW; Interface R4 between source ASN-GW and the target ASN-GW, R6 interface between target ASN-GW and the target BS and the R1 interface between target BS and the MSS are to MSS.
In this case, among the said source ASN-GW, buffer can be set, also buffer can be set.Only listed the flow process when buffer not being set among Fig. 7.For the situation that is provided with buffer, identical with associated description in the foregoing description, be not described in detail.
Step 2, source/when target ASN-GW decision triggered R3 relocation, target ASN-GW notice HA set up the new R3 passage from HA to target ASN-GW to this MSS, and close from HA to the source ASN-GW to the R3 passage of this MSS.
Step 3, source ASN-GW report the downlink data of the MSS that receives through Interface R4 and are forwarded to target ASN-GW; (assurance was reported through the downlink data of the MSS of original Interface R3 transmission from HA and was all arrived source ASN-GW, and this time can be the fixed value of an estimated value or a configuration a period of time after target ASN-GW notification source ASN-GW has set up new Interface R3.The present invention controls the time that discharges the R4 passage through starting the timer that is provided with after successfully setting up new Interface R3.)
The downlink data packet of step 4, MSS is through the Interface R3 between HA and the target ASN-GW, and R6 interface between target ASN-GW and the target BS and the R1 interface between target BS and the MSS are to MSS.
Technical scheme by the invention described above provides can be found out; Method of the present invention is when switching; Through the data channel between source network element and target network element; Give corresponding target network element with the MSS data message forwarding that or sends to the source network element, and through the CSN that sets up to the data channel between target network element, send the data message of the MSS that sends to said target network element; Said target network element sends the data message that receives to corresponding MSS.Therefore the present invention can guarantee the harmless transmission of business datum; Solved in the prior art that the data packet loss compares problem of higher when ASN-GW taking place switching; And behind the employing retransmission mechanism, the time delay that causes is than problem long and system signaling and data transfer overhead increase; Solved and formation or buffer memory must be set in ASN-GW in the prior art and require ASN-GW to have the problem of bigger memory space; And lossless migration process of the present invention is carried out in ASN fully; Setting up new R3 does not need the additional functionality of CSN side apparatus, has therefore reduced requirement and the dependence to CSN.
In addition, the present invention with when service is set up, just distributed spatial cache to compare for Packet Service in the past, the method for dynamically setting up buffer has reduced the requirement for memory space, has improved the utilance of buffer.And, can improve the service feature of low packet loss ratio and low time delay through buffer forwarding lossless switch function.
Can't harm the optimum balance that the method for switching can reach system load and service quality according to the grade of service and quality of service requirement support, be unlikely to because all services are all increased storage forwarding lossless switch function and increase overhead; Also be unlikely to not support effectively harmless switching and can not reach the required service quality of user.
With technology in the past buffer memory is set in CSN and transmit to support switches and to compare, through the dynamic buffering device is set, can reduce the requirement for CSN device processes ability and memory on ASN-GW, minimizing is to the dependence of CSN equipment.To be distributed to the demand pressure of an equipment on a plurality of equipment, thereby reach effect of load balance.And the present invention realizes fairly simple.
The above; Be merely the preferable embodiment of the present invention, but protection scope of the present invention is not limited thereto, any technical staff who is familiar with the present technique field is in the technical scope that the present invention discloses; The variation that can expect easily or replacement all should be encompassed within protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection range of claim.