CN101001446A

CN101001446A - Switching method and system

Info

Publication number: CN101001446A
Application number: CNA2006100055245A
Authority: CN
Inventors: 郑潇潇
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2006-01-09
Filing date: 2006-01-09
Publication date: 2007-07-18

Abstract

This invention discloses a switch method including: A, a terminal sends a measurement report to a source play node, which exchanges information with a target play node for preparing terminal switch, B, the source node transmits context data to the target node and stores them, C, the target node carries out the switch operation, D, the terminal judges if the switch is succeeded, if so, the terminal sends the confirmation message to the target node, otherwise enters into step E, E, the terminal sends a fault message to the source node. This invention also discloses a switch system.

Description

A kind of changing method and system

Technical field

The present invention relates to the communications field, relate in particular to a kind of changing method and system.

Background technology

Universal mobile telecommunications system (UMTS Universal Mobile Telecommunication Systems) is to adopt the 3-G (Generation Three mobile communication system) of WCDMA access system (WCDMA Wide-band Code Division MultipleAccess) air interface.Usually also the UMTS system is called the WCDMA communication system.

On function, network element can be divided into Radio Access Network (RAN RadioAccess Network) and core net (CN Core Network).Wherein Radio Access Network is used to handle all and wireless function associated, and CN handles that all voice calls in the UMTS system are connected with data and the exchange and the route of external network, and its system configuration as shown in Figure 1.

The network element of UMTS system comprises terminal (UE User Equipment), UMTS Terrestrial radio access network (UTRAN UMTS Terrestrial Radio Access Network), CN, operation maintenance center (OMC Operation and Maintenance Center) functional entity, and grid constitutes as shown in Figure 2.

Fig. 2 has illustrated the main interface of WCDMA system simultaneously.Wherein, the Uu interface is the wave point of WCDMA.UE is linked into the fixed network part of UMTS system by the Uu interface, and the Iu interface is the interface that connects UTRAN and CN.The Iur interface is the interface that connects between the RNC, and the Iur interface is the distinctive interface of UMTS system, is used to the mobile management to travelling carriage among the RAN.Iub interface is the interface that connects Node B and RNC.

Wave point refers generally to the Uu interface between UE and the network, the protocol architecture of wave point as shown in Figure 3, wherein:

GC: general controls;

BMC: broadcasting/multileaving control protocol;

Nt: notice;

RLC: Radio Link control;

DC: special-purpose control;

MAC: medium access control;

RRC: Radio Resource control;

PHY: physical layer;

PDCP: packet data convergence protocol.

This wave point is divided into three protocol layers, is respectively physical (L1), data link layer (L2) and network layer (L3).

Wherein L2 comprises four sublayers such as MAC, RLC, PDCP, BMC.

Real time business is generally used RLC UM mode transfer in the existing UMTS R6 system, and the MAC layer can be according to service selection HSDPA or DCH carrying.The division cascade of RLC UM PDU is that indication is finished according to the MAC layer.

In 3GPP TSG RAN#26 meeting, having passed through research project " Evolved UTRA andUTRAN " is LTE (Long Term Evolution).The reason of setting up this project is: along with the introducing of enhancement techniques such as HSDPA, Enhanced Uplink, the 3GPP wireless access technology is that very high competitiveness is arranged in a few years from now on.And in order to guarantee the competitiveness of more longer time (as 10 years or longer), the Long Term Evolution of 3GPP wireless access technology need be considered.

The pith of this Long Term Evolution comprises the time delay of reduction, higher user data rate, improved power system capacity and covering and for the cost of operator's reduction.In order to reach above-mentioned target, the wave point of evolution and wireless network architecture all should be considered.

For the demand of the various performances of network that satisfy this Long Term Evolution, corresponding improvement all can take place in network configuration, wave point, protocol stack function.Existing protocol layer structure causes the function of a lot of repetitions, such as the re-transmission of RLC and media access control sublayer, division cascade or the like.In order to reduce to postpone and simplify agreement, the function of these repetitions must be considered to simplify.In addition, the all-IP requirement that the LTE system proposes, it is professional that promptly Network Transmission all is based on the IP bag, and the mechanism that this brand-new demand also needs to respond goes to guarantee.

In the LTE network, network configuration becomes 2 node layer structures by 3 original node layer structures, and the RNC function is split in Node B (Node B) and the gateway node (GW Gateway).In the evolvement network in future, the business of how different demands also needs to satisfy the requirement of low packet loss ratio, such as Video Phone or the like with the needs design that is considered for some special real time business.In the discussion of evolvement network, because the utilization of shared channel, soft handover is cancelled simultaneously.Therefore, the data interruption brought of direct-cut operation or the problem optimization that need be considered break period.Some companies have proposed the scheme of some solutions, such as data forwarding mode (UE from an enode b (NB) direct-cut operation to another NB, source NB with do not send in the buffer memory and retransmit the data (ARQ business) that are not identified in the buffer memory and all issue target NB.) or the bi-casting mode (before switching, GW sends data to source NB and target NB.) etc.But the while is owing to real time business and non-real-time service characteristic is different, require also inequality, such as for non-real-time service, the harmless handover scheme of data forwarding scheme can well be finished its demand, but for real time business, break period in the data forwarding scheme, can not satisfy its demand, so some new schemes will be considered.

In UMTS R6 system, hard handover scheme does not have the auxiliary of data forwarding or bi-casting, can cause certain loss of data or interrupt time delay, and when striding the switching of RNC, the RLC entity of receiving terminal can be reset, and parameter will be refreshed.And the direct-cut operation in the system mainly contains with two kinds of frequently direct-cut operation and alien frequencies direct-cut operations, is used to not have the RNC co-frequency cell of striding of Iur interface to switch or the Iur interface is arranged with direct-cut operation frequently, but Iur interface resource anxiety.Alien frequencies has no idea to do soft handover, can only direct-cut operation.

In the research process of LTE network, there are some companies to propose the scheme of big data forwarding.

As shown in Figure 4 and Figure 5, be the schematic flow sheet that first company proposes solution, Fig. 5 has shown the process that time delay forms, and as seen from the figure, mainly may further comprise the steps:

S011, UE send measurement report to SNB;

S012, source enode b (SNB) are done and are measured judgement;

S013, SNB send handover preparation request to target enode b (TNB), comprising some capacity informations and contextual information;

S014, TNB reserved resource are given UE;

S015, TNB set up user's face with GW and are connected;

S016, TNB transmission is ready to complete message and switches indication to GW to SNB and transmit path;

After S017, SNB receive and be ready to complete indication, send and switch indication to UE;

S018, while SNB stop to transmit and send not send in the own buffer memory in data and the re-transmission buffer memory does not have the data of affirmation to TNB;

S019, since two NB between do not have interface, data need be transmitted from GW;

GW began to send data to TNB after S0110, SNB data all sent to GW;

S0111, these data of TNB buffer scheduling;

S0112, UE begin the L1 synchronizing process after receiving switching command, prepare to connect with new NB;

S0113, finish synchronous back and send H/O confirm message to NB;

After receiving, S0114, NB begin to send data;

S0115 and transmission H/O finish indication to SNB;

S0116, SNB discharge and are connected with the GW data surface accordingly.

As shown in Figure 6, be the schematic flow sheet that second company proposes solution, there is interface can directly transmit data in this scheme between SNB and the TNB.

In the above-mentioned prior art, data forwarding scheme is primarily aimed at be the RLC function at NB, the mobile management function is also at NB, so Handover decision is finished by NB.It is not have interface between the Node B that the scheme of first company is primarily aimed at, and what the scheme of second company was primarily aimed at is to have interface can directly transmit data between the Node B.These schemes all are to stop to carry out dataforward after the transmission at transmitting terminal, though Data forwarding has solved the problem of harmless switching, have the breaktime of long period.Here Break time is defined as the time that SNB stops to transmit and begins the transmission time to TNB, causes mainly be break period because the transmission time of data from SNB to TNB, and the TNB scheduling time.Also have a problem to be simultaneously if handoff failure, UE feeds back to SNB after receiving HO command message is failure, and this moment, SNB stopped transmission, and carries out data forward and can make UE longer break period.For some non-real-time service, also time delay is had higher requirements, therefore consider to optimize this break period, consider simultaneously to make data forwarding also can be used for some real time business.

Summary of the invention

The invention provides a kind of changing method and system, in order to solve the excessive problem of time delay in the handoff procedure that exists in the prior art.

The inventive method comprises:

A kind of changing method comprises:

A, terminal send measurement report to the source enode b, and source enode b and target enode b interactive information are carried out terminal and switched preparation;

B, source enode b are to transmission of target enode b and preservation terminal context data;

C, target enode b are carried out handover operation;

Whether D, terminal judges are switched successful, if terminal sends switch acknowledgment message to the target enode b, otherwise enters step e;

E, terminal send switch failure information to the source enode b.

Described steps A further comprises:

A1, terminal send measurement report to the source enode b, and the source enode b is done switch decision according to described measurement report;

A2, source enode b send handover preparation request to the target enode b;

A3, target enode b after gateway node is done routing update, upgrade indication to source enode b transmit path to gateway node transmit path update request;

A4, source enode b send switching command to terminal.

Described step B also comprises:

B1, described source enode b continue to send context data to terminal.

Described step B1 further comprises:

B11, source enode b stopped to send context data to terminal after the very first time.

Among the described step B11, the described very first time is the preset threshold time.

Described threshold time is that required time is finished in the terminal switching.

Among the described step B, also comprise source enode b zhang information about the transmission of target enode b, comprise the numbering plan information that adopts in the described contextual information;

Among the described step C, the terminal context data that the target enode b sends to terminal is according to described numbering plan numbering.

Described numbering plan comprises:

The source enode b sends to the target enode b with the first terminal context data, first numbering in the buffer memory;

The target enode b is numbered the terminal context data that receives from the source enode b according to described first and is numbered, and according to described numbering the terminal context data is sent to terminal.

Among the described step B, described source enode b transmits by the IP transmission or by gateway forwards to target enode b transmission terminal context data.

Among the described step D,, then also comprise the terminal context data that source enode b deletion is preserved if described terminal sends switch acknowledgment message to the target enode b.

Among the described step D,, comprise also then that terminal is preserved the switching state report if described terminal sends switch acknowledgment message to the target enode b.

In the described step e, also comprise and return steps A.

A kind of changing method comprises:

B, source enode b are to target enode b and terminal transmission context data;

C, target enode b are carried out the terminal handover operation.

Described steps A further comprises:

A2, source enode b send handover preparation request to the target enode b;

A3, target enode b after gateway node B does routing update, upgrade indication to source enode b transmit path to gateway node B transmit path update request;

A4, source enode b send switching command to terminal.

Described step B further comprises:

B1, source enode b stopped to send the terminal context data to terminal after the very first time.

Among the described step B1, the described very first time is the preset threshold time.

Among the described step B, described source enode b starts numbering plan when target enode b transmission terminal context data;

Described numbering plan comprises:

Among the described step B, described source enode b directly transmits by IP or passes through gateway forwards to target enode b transmission context data.

Among the described step B, comprise that also the source enode b preserves described terminal context data.

Described method also comprises step:

E, terminal send switch failure information to the source enode b.

Among the described step D, if described terminal sends switch acknowledgment message to the target enode b, then the source enode b is deleted the terminal context data of preserving.

Switched system of the present invention comprises:

A kind of switched system comprises terminal, for terminal provides the source enode b and the target enode b of access and gateway node;

Described terminal is provided with:

The measurement report transmitting element is used for sending measurement report to the source enode b, and triggering terminal is switched;

The switching result performance element according to the terminal switching result, sends switch acknowledgment message to the target enode b, perhaps sends switch failure information to the source enode b;

Described source enode b is provided with:

Terminal context transfer unit is used for to target enode b transmission terminal context data;

Described source enode b also is provided with terminal context memory cell, is used to store the terminal context data to the transmission of target enode b.

Described source enode b also is provided with:

Terminal context transmitting element is used for sending the terminal context data of source enode b to the transmission of target enode b to terminal.

Described source enode b also is provided with:

Numbering plan is provided with the unit, is used for to target enode b transmission contextual information numbering plan information being set;

Described target enode also is provided with:

The number information extraction unit is used for extracting numbering plan information at source enode b transmission contextual information;

Numbering is provided with the unit, is used for according to described numbering plan, for the terminal context data that receives from the source enode b is numbered, and according to described numbering the terminal context data is sent to terminal.

A kind of switched system comprises terminal, for terminal provides the source enode and the target enode of access,

Described terminal is provided with:

Described source enode b is provided with:

Described source enode b also is provided with terminal context transfer unit,

Be used for sending the terminal context data of source enode b to the transmission of target enode b to terminal.

Described source enode b also is provided with:

Terminal context memory cell is used to store the terminal context data to the transmission of target enode b.

Described source enode b also is provided with:

Described target enode also is provided with:

Necessarily optimize the break period that the present invention is directed to direct-cut operation, makes direct-cut operation interrupt time delay and reduce, and especially when the UE handoff failure, still can keep the transmission of data, can not cause professional interruptions in transmissions.Make the subplan of this direct-cut operation of data forwarding can satisfy in real time and the transmission demand of non-real-time service.

Among the present invention program, because the source enode b is in handoff procedure, in the time of target enode b transmission terminal context data, also to preserve the terminal context data, like this, behind the terminal handoff failure, can carry out terminal switching process apace again, reduced the terminal time delay of direct-cut operation.

Among the present invention program, because the source enode b is in handoff procedure, in the time of target enode b transmission terminal context data, also to like this, just can make terminal in handoff procedure to terminal transmission terminal context, can interrupting service, give favorable user experience of terminal use.

Among the present invention program,, can significantly reduce handover delay by the use of numbering plan.

Description of drawings

Fig. 1 is the application schematic diagram of UMTS in the prior art;

Fig. 2 is the structural representation of UMTS in the prior art;

Fig. 3 is a radio interface protocol architecture schematic diagram in the prior art;

Fig. 4 and Fig. 5 provide the switching flow schematic diagram of scheme for first company in the prior art;

Fig. 6 provides the switching flow schematic diagram of scheme for second company in the prior art;

Fig. 7 is the schematic flow sheet of the embodiment of the invention 1;

Fig. 8 is the schematic flow sheet of the embodiment of the invention 2;

Fig. 9 is a system configuration schematic diagram of the present invention.

Embodiment

Below in conjunction with the specific embodiment of the present invention is described.

In the existing scheme, UE finish L1 synchronously before, SNB stops to transmit and the data forward that will remain in the buffer memory gives TNB, tentation data need be transmitted from GW, GW can not send data to TNB and arrive up to the data of SNB forward behind path swtich, have stopping of a transmission for GW, can cause extra time delay like this, especially behind handoff failure.

The present invention is after UE receives HO command, and before the successful switch, SNB carries out dataforwarding earlier but do not stop transmission.SNB is transferred to TNB with the context in the transmission buffer after the path switch indication that receives GW, make TNB know the data of getting off from GW need from which open numbering.(that store in the re-transmission buffer memory for the non-real-time service of ARQ here is the SDU that adds head, and need the SDU that high level gets off be numbered for real time business).Send to TNB with the data that are about to transmission and retransmit in the buffer memory, but SNB does not delete these data, send but preserve and continue.The Path Switch of GW can do in advance, and TNB can begin transmission immediately after obtaining the H/O confirm message of UE like this.Here TNB does not need the data of waiting for that SNB forward comes, and can earlier the data behind GW path switch be sent to UE earlier.If promptly after TNB receives the confirm message of UE, also do not receive the data of SNB, can be earlier the new data of GW be sent to UE.Here need the out of order transmission of transmitting terminal and the support that receiving terminal reorders.TNB sends complete message informing SNB after receiving the confirm message of UE, and at this moment SNB just stops transmission, and data in buffer is all deleted.

Embodiment 1:

As shown in Figure 7, be the switching flow schematic diagram of the embodiment of the invention 1, there is not interface between SNB and TNB among the embodiment 1, data need be transmitted through GW, as seen from the figure, mainly may further comprise the steps:

S11, terminal send measurement report to SNB, the triggering terminal switching flow.

When terminal will be switched, it sent measurement report to SNB, by measurement report terminal related information is sent to SNB, with the triggering terminal switching flow.

S12, SNB carry out switch decision (HO decision).

SNB is HO decision according to described measurement report, and according to the related data information that provides in the measurement report, whether decision switches.

S13, SNB send handover preparation request Preparation Request to TNB.

SNB notice TNB preparation switches preparation by TNB.

S14, TNB send path switch reques to GW.

TNB finish be connected with the data surface of GW set up after, send path switch reques to GW, carry out path switch by GW.

S15, GW send Path switch indication to SNB.

GW sends indication to SNB after being Path switch, and begins to send data to TNB.

S16, SNB start the numbering function.

For real time business, after SNB receives Path switch indication, can start the numbering function, the numbering function promptly adds sequence number (common no ARQ transmits the PDU that can not get off to high level and is numbered) to each SDU, SNB sends to TNB with the numbering of last SDU among the buffer with the context form, TNB is numbered for the SDU that receives from GW then, and the numbering function can stop the numbering function after TNB receives the data of SNB forward.

For non-real-time service, after SNB receives path switch, the ARQ sequence number of last PDU in the transmission buffer is sent to TNB, TNB will be according to this sequence number for sending the SDU numbering of getting off from GW.Here that buffer memory is the SDU of process numbering in the ARQ re-transmission buffer memory.

S17, SNB send the context information of transmission to TNB.

SNB sends the context information of transmission to TNB after receiving the indication of GW, how the data that make TNB know to receive from GW this number.

S18, SNB send HO command to UE, and UE begins the L1 synchronizing process, prepare the wireless connections of foundation and TNB.

S19, SNB are to TNB and terminal transmission terminal context data.

In this step, SNB will transmit context and send to TNB, then data among the buffer (if the ARQ business comprises the data that do not have among the re-transmission of the ACKed buffer) be sent to TNB, but will not delete these data, and send these data of transmission to terminal simultaneously.

By this step, can keep professional continuity so that UE in the process of switching, still can receive the downlink data that network sends.

SNB can select immediately after these data of forward are given TNB, (is controlled by timer) after a period of time to stop to send to UE, does not perhaps stop to finish (receiving complete message) up to HO.

In this step, SNB sends data to GW, transmits by GW, and GW needn't wait for the data of SNB and new data can be sent to TNB, preferentially transmit if SNB is transferred to GW.Buffer scheduling waited for that the confirm of UE indicates after TNB received data from GW.

S110, UE send HO confirm to TNB.

UE begins the L1 synchronizing process after receiving switching command, prepares to connect with new NB, finishes synchronous back transmission HO confirm message to TNB, and UE indication TNB L1 finishes the handover success of eating dishes without rice or wine synchronously.

S111, TNB send data to UE.

Beginning sent data to UE after TNB received the HO confirm message that UE sends.

If TNB does not still receive SNB and transmits data after receiving UE confirm message, can send the new data of the GW that arrives scheduler earlier, if receive the data of receiving SNB before UE indicates, preferentially send the SNB legacy data.

TNB needs out of order transmission support among the embodiment 1, and for real time business, cancellation is to the numbering of high-rise SDU immediately or after a period of time after receiving the SNBforward data for TNB, and indication simultaneously gives the UE can be by to the sign of previous SDU etc.

S112, TNB send H/O complete and indicate to SNB.

Finish if switch, TNB sends H/O complete message to SNB.

UE starts special re-ordering function (needing sliding window to wait for the data of out of order arrival) and supports the out of order transmission of TNB (needn't transmit from big to small according to the SN sequence number after sending H/O complete message, and it is little to pass the big back biography of SN earlier), if the ARQ business (business that need retransmit with ARQ), control status report sends, and the status report that is sent to transmitting terminal by receiving terminal is notified the other side reception condition.

After S113, SNB receive complete message, delete all data.

After SNB receives complete message, stop transmission if transmission does not stop, and delete all data, SNB release behind deleted data is connected with UE.

In the such scheme, TNB need support out of order transmission.The TNB scheduling can be supported and will transmit from the high priority data that SNB forward comes.

For the ARQ business, TNB can carry out invalid re-transmission protection (utilizing methods such as timer) for the status report of UE, keeps this status report.

Embodiment 2:

As shown in Figure 8, be the schematic flow sheet of the embodiment of the invention 2, as seen from the figure, embodiment 2 may further comprise the steps:

S21, terminal send measurement report to SNB, the triggering terminal switching flow.

S22, SNB carry out switch decision.

S23, SNB send handover preparation request Preparation Request to TNB.

S24, TNB send path switch reques to GW.

S25, GW send Path switch indication to SNB.

S26, SNB start the numbering function.

S27, SNB send the context information of transmission to TNB.

S28, SNB send HO command to UE, and UE begins the L1 synchronizing process, prepare the wireless connections of foundation and TNB.

S29, SNB are to TNB and terminal transmission terminal context data.

S210, UE send HO confirm to TNB.

S211, TNB send data to UE.

S212, UE send H/O failure and indicate to SNB.

If the UE handoff failure, then UE sends H/O failure to SNB, and SNB sends indication to TNB and GW, reselects and switches or continue transmission, and the business of UE just can not interrupted like this.

As shown in Figure 9, be the structural representation of switched system of the present invention, as seen from the figure, this switched system comprises terminal 100, for terminal provides the source enode b 200 and the target enode b 300 of access and gateway node 400;

Described terminal 100 is provided with:

Measurement report transmitting element 101 is used for sending measurement report to source enode b 200, and triggering terminal is switched;

Switching result performance element 102 according to the terminal switching result, sends switch acknowledgment message to target enode b 300, perhaps sends switch failure information to source enode b 200;

Described source enode b 200 is provided with:

Terminal context transfer unit 201 is used for to target enode b 300 transmission terminal context datas;

The present invention also is provided with at described source enode b 200:

Terminal context memory cell 202 is used to store the terminal context data to 300 transmission of target enode b.

Terminal context transmitting element 203 is used for sending the terminal context data of source enode b 200 to 300 transmission of target enode b to terminal 100.

The present invention also is provided with at described source enode b 200:

Numbering plan is provided with unit 204, is used for to target enode b 300 transmission contextual informations numbering plan information being set;

Described target enode 300 also is provided with:

Number information extraction unit 301 is used for extracting numbering plan information at source enode b 200 transmission contextual informations;

Numbering is provided with unit 302, is used for according to described numbering plan, for the terminal context data that receives from source enode b 200 is numbered, and according to described numbering the terminal context data is sent to terminal 100.

By this switched system, can be in the process that terminal is switched, terminal is stored and sent to the terminal context that the source enode b is sent to the target enode b, can reduce the terminal time delay for switching like this, and increase the fail safe that terminal is switched.

By number information extraction unit and the numbering that is arranged at source enode b and target enode b the unit is set, can be in the process that terminal is switched, for being is numbered from the terminal context data that the source enode b receives, and the terminal context data is sent to terminal according to described numbering.To reduce the terminal time delay for switching.

Obviously, those skilled in the art can carry out various changes and modification to the present invention and not break away from the spirit and scope of the present invention.Like this, if of the present invention these are revised and modification belongs within the scope of claim of the present invention and equivalent technologies thereof, then the present invention also is intended to comprise these changes and modification interior.

Claims

1, a kind of changing method is characterized in that, comprising:

C, target enode b are carried out handover operation;

E, terminal send switch failure information to the source enode b.

2, the method for claim 1 is characterized in that, described steps A further comprises:

A2, source enode b send handover preparation request to the target enode b;

A4, source enode b send switching command to terminal.

3, the method for claim 1 is characterized in that, described step B also comprises:

B1, described source enode b continue to send context data to terminal.

4, method as claimed in claim 3 is characterized in that, described step B1 further comprises:

5, method as claimed in claim 4 is characterized in that, among the described step B11, the described very first time is the preset threshold time.

6, method as claimed in claim 5 is characterized in that, described threshold time is that required time is finished in the terminal switching.

7, the method for claim 1 is characterized in that,

Among the described step B, comprise that also the source enode b to target enode b transmission contextual information, comprises the numbering plan information that adopts in the described contextual information;

8, method as claimed in claim 7 is characterized in that, described numbering plan comprises:

9, the method for claim 1 is characterized in that, among the described step B, described source enode b transmits by the IP transmission or by gateway forwards to target enode b transmission terminal context data.

10, the method for claim 1 is characterized in that, among the described step D, if described terminal sends switch acknowledgment message to the target enode b, then also comprises the terminal context data that source enode b deletion is preserved.

11, the method for claim 1 is characterized in that, among the described step D, if described terminal sends switch acknowledgment message to the target enode b, then also comprises, terminal is preserved the switching state report.

12, the method for claim 1 is characterized in that, in the described step e, also comprises and returns steps A.

13, a kind of changing method is characterized in that, comprising:

B, source enode b are to target enode b and terminal transmission context data;

C, target enode b are carried out the terminal handover operation.

14, method as claimed in claim 13 is characterized in that, described steps A further comprises:

A2, source enode b send handover preparation request to the target enode b;

A4, source enode b send switching command to terminal.

15, method as claimed in claim 13 is characterized in that, described step B further comprises:

16, method as claimed in claim 15 is characterized in that, among the described step B1, the described very first time is the preset threshold time.

17, method as claimed in claim 16 is characterized in that, described threshold time is that required time is finished in the terminal switching.

18, method as claimed in claim 13 is characterized in that,

19, method as claimed in claim 18 is characterized in that, described numbering plan comprises:

20, method as claimed in claim 13 is characterized in that, among the described step B, described source enode b directly transmits by IP or passes through gateway forwards to target enode b transmission context data.

21, method as claimed in claim 13 is characterized in that, among the described step B, comprises that also the source enode b preserves described terminal context data.

22, method as claimed in claim 21 is characterized in that, also comprises step:

E, terminal send switch failure information to the source enode b.

23, method as claimed in claim 22 is characterized in that, among the described step D, if described terminal sends switch acknowledgment message to the target enode b, then the source enode b is deleted the terminal context data of preserving.

24, method as claimed in claim 22 is characterized in that, among the described step D, if described terminal sends switch acknowledgment message to the target enode b, then also comprises, terminal is preserved the switching state report.

25, a kind of switched system comprises terminal, for terminal provides the source enode b and the target enode b of access and gateway node;

Described terminal is provided with:

Described source enode b is provided with:

It is characterized in that described source enode b also is provided with terminal context memory cell, be used to store terminal context data to the transmission of target enode b.

26, system as claimed in claim 25 is characterized in that, described source enode b also is provided with:

27, system as claimed in claim 26 is characterized in that, described source enode b also is provided with:

Described target enode also is provided with:

28, a kind of switched system comprises terminal, for terminal provides the source enode and the target enode of access,

Described terminal is provided with:

Described source enode b is provided with:

It is characterized in that described source enode b also is provided with terminal context transfer unit,

29, system as claimed in claim 28 is characterized in that, described source enode b also is provided with:

30, system as claimed in claim 29 is characterized in that, described source enode b also is provided with:

Described target enode also is provided with: