CN101653026B - Handoff of data attachment point - Google Patents

Abstract

In a communication system in which a gateway entity is linked to a plurality of infrastructure entities which in turn are operable to communicate with an access terminal, the access terminal needs first to establish a data attachment point (DAP) with one of the infrastructure entities. Handoff of the DAP from one infrastructure entity to another infrastructure entity is initiated by the access terminal. The access terminal weighs factors such as the link conditions with the various infrastructure entities, the time since the last DAP handoff, and time duration communicating with the current infrastructure entity before proceeding with the DAP handoff.

Description

Switching to data attachment point

Claimed priority according to 35 U.S.C. § 119

U.S. that patent application claims were submitted to respectively on April 6th, 2007, on April 13rd, 2007 and on June 12nd, 2007 State's provisional application No.60/910,628,60/911,858 and 60/943,459 priority, these provisional applications are assigned to this The assignee of application, therefore explicitly by being incorporated by the application.

Technical field

The present invention is generally related to communication, in particular to switch data attachment point in a wireless communication system.

Background technology

In telecommunications, especially in radio communication, communication environment be not it is static, but dynamically.Set in mobile communication In putting, such as some communication entities of access terminal (AT) can be moved from a position to another position in different time points It is dynamic.

With reference to Fig. 1, which illustrates the sketch illustrated to example communication system.In the following description, used with The associated term of Ultra-Mobile Broadband (UMB) system.The basic terminology and operating principle of UMB systems can be from telecommunications industry association (TIA) entitled " Interoperability published by the third generation partner program 2 (3GPP2) set up Find in the publication of Specification " 3GPP2-A.S0020.As shown in figure 1, in the interior of Radio Access Network (RAN) 12 Portion, for example, in Ultra-Mobile Broadband (UMB) system, AT 14 within the system via evolution base station (eBS) 18 wirelessly Access core network 16.EBS 18 is between AT 14 and access gateway (AGW) 20 as data exchange entity.AGW 20 is direct Access core network 16.For example, core network 16 can be the Internet.

In FIG, eBS 18 as AT 14 data attachment point (Data Attachment Point) (DAP).More Body ground, for example, there is forward link traffic to bind (binding) as the eBS 18 and AGW 20 of DAP, such as exists, according to Proxy-mobile IP (PMIP) agreement announced by Internet Engineering Task group (IETF) is operated.According to PMIP agreements, AGW Forward link data business is sent to DAP (being eBS 18 in this instance) by 20, and then data service is sent to AT 14 by DAP. The network entity with 20 last bindings of AGW is carried out as the eBS 18 of DAP.

In wireless environments, AT 14 is mobile.That is, AT 14 can be moved in same RAN 12 from a position Another interior position, or move to different RAN.

Below with reference to Fig. 2, ambulant another sketch of explanation AT 14 is shown.

In FIG. 2, it is assumed that the AT 14 for originally communicating with eBS 18 now moves away from eBS 18 and beginning is led to eBS 22 Letter.EBS 22 is referred to as forward link service eBS (FLSE) of AT 14 now, because eBS 22 is directly communicated with AT 14 And exchange data.However, updating with the still no any bindings of AGW 20.That is, the net of last binding is carried out with AGW 20 Network entity remains eBS18, and any binding hereafter no with AGW 20 updates.Similarly, the still conducts of eBS 18 DAP.In this case, the data is activation from AGW 20 is given eBS 18 in this case as DAP, then by data road By to AT 14, the eBS 20 as FLSE is reached.According to the data path 24 pairs shown in Fig. 2 from AGW 20 to AT 14 number It is route according to packet.

Even if AT 14 is had roamed into outside the overlay area serviced by eBS 18, eBS 18 remains the DAP of AT 14.Its Reason is, in wireless setting, depending on the mobility of AT 14, eBS 18 is possible to the FLSE for becoming AT 14 again.For example, AT 14 is likely located on the boundary line of the overlay area that both eBS 18 and eBS 22 are provided.So, AT 14 may only with eBS 22 are provisionally communicated.If however, the communication between AT 14 and eBS 22 is not interim, at least from utilization of homeward voyage From the perspective of, it is not the effectively utilizes to the communication resource by tortuous 24 routing of data of data path packet.In addition, This also affects grouped data delay.Alternatively, DAP is preferably switched to eBS 22 from eBS 18.Switch for the DAP, eBS 22 carry out forward link traffic binding firstly the need of with AGW 20.After forward link traffic binding procedure is successfully completed, eBS 22 become current DAP.Then, packet is routed to into AT 14 from AGW 20 via eBS 22, the data path in such as Fig. 2 Shown in 26.DAP is switched to from BS 18 by eBS 22 based on specified criteria, for example, the communication that AT and eBS 22 is carried out is being determined After continue for predetermined amount of time.

So far, switching or selection (referred to as DAP switchings) to DAP is that AN is initiated mostly.In the switching that AN is initiated, cut Process is changed for AT 14 is transparent.However, problem occurs in the case where AT 14 is unaware of switching.For example, it is contemplated that DAP As a result it is probably unexpected DAP.Under asynchronous environment especially so, wherein various communication entities are not mutually in step.Return Return Fig. 2, it is again assumed that AT 14 is on eBS 18 and the border of overlay area both eBS 22.In the switching that AN is initiated, example Such as sense the presence of AT 14 via downlink signal strength, eBS 18 and eBS 22 all attempt by with 20 notes of AGW Volume forward link binding is becoming DAP.It is also assumed that AT 14 is fully located in the overlay area of the offers of eBS 18, so as to eBS 18 Should be 14 optimal DAP of AT.If however, the registration message sent and received between AGW 20 and eBS 22 compares AGW EBS 22 faster, then may be had precedence over eBS 18 and be appointed as DAP by the registration message between 20 and eBS 18, just with it is desired On the contrary.The recovery that the DAP specified to mistake is carried out, even if the communication session to being related to is not fatal, which requires extra letter Order and message transmission, so as to unnecessarily hinder the communication resource.

Accordingly, it is desirable to provide that there is more high accuracy and deterministic DAP specified schemes, such that it is able to more effectively Using the communication resource.

The content of the invention

In a communications system, gateway entity is linked to multiple communication entities, and the plurality of communication entity is then operable and accesses Terminal is communicated, and the access terminal sets up data attachment point (DAP) firstly the need of with the communication entity.Institute State access terminal to initiate for the DAP to be switched to another communication entity from a communication entity.Carry out the DAP switchings with Before, the access terminal can consider many factors, such as：With the link circuit condition between multiple communication entities, the last time DAP Time since switching, and the persistent period communicated between present communications entity.In order to avoid there are multiple communication entities Any race condition of DAP is registered as, access terminal refers to from multiple communication entities the timestamp for receiving message.Additionally, Multiple communication entities can also be for current DAP login states interchange messages.

According to the detailed description for being given below in conjunction with the accompanying drawings, those skilled in the art will be clear that the feature and excellent of the present invention Gesture, in the accompanying drawings, identical reference represents identical part.

Description of the drawings

Fig. 1 is the sketch for illustrating example communication system；

Fig. 2 is the ambulant another sketch for illustrating access terminal in communication system；

Fig. 3 is the sketch of the relation for illustrating each communication entity for arranging according to an exemplary embodiment of the present；

The call flow chart of the different communication inter-entity message stream that Fig. 4 is operated in showing asynchronous system, DAP therein Switching does not have AT to aid in；

The call flow chart of the different communication inter-entity message stream that Fig. 5 is operated in showing synchronization system, DAP therein Switching is AT auxiliary；

The flow chart that Fig. 6 shows the process that AT is performed during it is determined that the DAP of AT auxiliary switches；

Fig. 7 shows the call flow chart of message flow between the different communication entity operated in synchronization system, wherein DAP switchings aided in but carried out under the request of a communication entity in multiple communication entities by AT；

Fig. 8 shows the DAP of the determination AT auxiliary carried out under the request of AT one in multiple network entities are answered and cuts The flow chart of performed process during changing；And

Fig. 9 is for performing showing for its hard-wired part of device of DAP handoff procedures according to exemplary embodiment It is intended to.

Specific embodiment

To enable those skilled in the art to realize or using the present invention, shown below is description.For explanation Purpose, some details are elaborated in explained below.It should be understood that ordinary skill will recognize that, Ke Yi These details are not used in the case of realize the present invention.In other examples, in order to avoid because Unnecessary detail is to this Invention causes vague description, does not elaborate structure known to some and process.Therefore, the present invention is not limited to shown Embodiment, but it is consistent with the widest scope of principle disclosed in the present application and feature.

Additionally, in the following description, for simple and clear for the sake of, used with telecommunications industry association (TIA) by the 3rd For the term that Ultra-Mobile Broadband (UMB) technology that partner program 2 (3GPP2) is announced is associated.It is emphasized that this It is bright to be also applied for other technologies, it is all such as relating to CDMA (CDMA), time division multiple acess (TDMA), frequency division multiple access (FDMA), orthogonal The technology of frequency division multiple access (OFDMA) etc. and associated standard.

Referring now to Fig. 3, which is schematically shown between the multiple communication entities for arranging according to an exemplary embodiment of the present Relation.

In figure 3, whole communication system briefly adopts reference 30 to represent.In communication system 30, access network Close (AGW) 32 and be linked to multiple evolution base stations (eBS), two therein are shown as eBS 34 and eBS 36.Can be by 34 Hes of eBS EBS 36 is arranged in same access network (AN) or different AN.In this example, eBS34 and 36 is 41 Hes of AN respectively A part of AN 43.Each in AN 41 and AN 43 may include one or more eBS and other entities.For clear and letter For the sake of bright, in figure 3 for each AN is only illustrated with an eBS.In the embodiment illustrated in figure 3, eBS 34 is to covering User in region 35 provides wireless access.Similarly, eBS36 provides the wireless access in overlay area 37.AGW 32 has To the link of core network 38, core network 38 can for example be the Internet.In another example, core network 38 can be envelope The Intranet closed in network.

Session reference network controller (SRNC) 40 is linked to AGW 32.SRNC 40 has several functions.For example, SRNC 40 is that access terminal (AT) (such as the AT 44 illustrated in Fig. 3) provides authentication function.Additionally, SRNC 40 is preparation and AT 44 Any new eBS of communication stores the communication session of AT 44.Usually, SRNC 40 also controls the paging of idle condition.

It is assumed that AT 44 can be moved between multiple radio nets, including AN 41 and AN 43.In order to allow AT 44 to connect Enter core network 38, AT 44 is firstly the need of the data attachment point (DAP) set up with communication entity (such as eBS34 or eBS 36). In this explanation and claims, by term " data attachment point " be construed to directly or indirectly to network gateway or Communication entity of the person from network gateway grappling data.As shown in Figure 3, for example, if eBS 34 is appointed as DAP, Data from core network 38 are arrived via data path 62 after by gateway entity (being AGW 32 in this case) Up to other communication entities (such as eBS 36) in the past, by communication entity (the being eBS 34 in this case) grappling as DAP. In the example, eBS 34 is via data path 62 directly from 32 grappling data of AGW.Which is also set up for reverse data flow.Also It is to say, the data received from other communication entities are before gateway entity is reached by DAP grapplings.

In the configuration specified by the DAP that AN is initiated, if meeting certain criterion, in eBS34 and eBS 36 Each carry out DAP assignment procedures.For example, when eBS 34 becomes forward link service eBS (FLSE) of AT 44, which can To start DAP assignment procedures.Therefore, if eBS 34 is current FLSE, login request message is sent to AGW by eBS 34 32.Afterwards, the process for being given according to proxy-mobile IP (PMIP) agreement announced by Internet Engineering Task group (IETF), AGW 32 carry out binding renewal with eBS 34.

It is assumed that communication system 30 is synchronization system.That is, all communication entities (such as AGW 38, eBS 34 and eBS 36 etc.) Operated according to main time reference.For example, primary standard can be global positioning system (GPS) time.In this case, may be used To arrange predefined DAP log-in protocols, for example, DAP is processed and is approved as by allowing the request to reaching at first, directly To next approval.If however, system 30 occurs problem when being asynchronous system.Because lacking main time reference, meeting The DAP for producing mistake is specified.

Fig. 3 is referred to reference to Fig. 4, the message flow sequence between different entities is it illustrates.It is assumed that system 30 is to make The system of the DAP handover schemes initiated with AN.It is also assumed that AT 44 moves to overlap of the overlay area 35 and 37 at its binding site Region 46.EBS 34 senses the presence of AT 44, sends login request message to AGW 32 in time t1, it is intended to AGW 32 The DAP of AT 44 is registered as, as shown in the message flow 48 in Fig. 4.It is assumed that the rule of " prerequisite variable " is adopted in system 30. The eBS 34 of login request message under the rule, is sent first, expects to become the DAP of AT 44.

When AT 44 is positioned in overlapping region 46, it is assumed that eBS 36 also senses the presence of AT 44.In the example In, eBS 36 also sends login request message to AGW 32 in time t2, as shown in the message flow 50 in Fig. 4.Here, t2 is late In t1.

Based on some reasons, AGW 32 is reached earlier than the message of message flow 48 via the message that message flow 50 sends.More Body ground, the message that eBS 36 sends reach AGW 32 in time t3, and the message that corresponding eBS 34 sends reaches AGW in time t6 32.In this case, time t6 is later than time t3.For example, there are more preferable communication conditions than eBS 34 in eBS 36 Aforementioned circumstances occur in communication environment.

For AGW 32, as which receives registration message from eBS 36 in time t3, according to " prerequisite variable " rule, AGW 32 ratifies the request and sends succeed in registration message to eBS 36 in time t4, and reaches eBS 36 in time t5.So as to, EBS 36 is successfully registered the DAP for AT 44.

It is assumed that AGW 32 also receives login request message from eBS 34 in time t6.Time t6 is later than time t5, wherein T5 is times of the eBS 36 to the DAP that 32 successful registrations of AGW are eBS 34.

Depending on the log-in protocol realized in AGW 32, AGW 32 may assume that eBS 34 wants to come as new DAP Replace current DAP eBS 36.

Then, AGW 32 sends succeed in registration reply to eBS 34 in time t7, and which reaches eBS 34 in time t8.So Afterwards, eBS 34 is used as new DAP.

In example above, it is to want eBS 34 to become DAP at the beginning, i.e. be not intended to the DAP that eBS 36 undertakes centre Role.Such DAP is specified and may be produced problem.Even if assuming not damage the data of communication session, such DAP is specified Lasting and poorly efficient business can be caused to route, so as to unnecessarily take up the communication resource.It is any to carry out tasting for Error Resiliency Examination necessarily may require that extra time and resource and extra complexity.

Although it shall yet further be noted that the PMIP binding messages that eBS 34 and eBS 36 are sent via message flow 48 and 50 respectively can have There is timestamp to prevent out of order binding from updating.However, as system 30 runs asynchronously, timestamp is for their work(of execution Can be probably invalid.Reason is, in asynchronous system each communication entity (such as eBS 34 and eBS 36) according to its from The time reference of body is running.The timestamp being sent on the binding message of AGW 32 is not for main time reference but is directed to The benchmark of single entity.The time reference of multiple entities can have big side-play amount each other.Therefore, previously described problem Still occur.

Fig. 5 is the message of the DAP handover schemes for showing that AT auxiliary or AT are initiated according to an exemplary embodiment of the present Flow graph.Hereinafter, term " AT auxiliary " and " AT is initiated " are interchangeably used.

Fig. 5 is referred to presently in connection with Fig. 3.It is assumed that AT 44 is initially communicated with eBS 34, wherein eBS 34 is and AGW The 40 last entities for carrying out PMIP bindings.So as to eBS 34 is the current DAP of AT 44.

AT 44 has set of routes (RS) in its memory.RS includes one group of communication entity, such as eBS 34 and eBS 36, there is the air interface with AT 44 to route for which, and in RS, each entity can be with AT 44 to link layer packet and IP point whereby Group carries out tunnel process, and vice versa.In DAP switchings AT auxiliary or that AT is initiated, the communication entity in the auxiliary RS of AT 44 Which entity to determine in RS should be DAP.

The many aspects that switch in of AT auxiliary are better than the switching that corresponding AN is initiated.

First, as it was noted above, competition shape occurs in asynchronous system (such as the system that above figure 4 illustrates) Condition.The DAP switchings of AT auxiliary are more avoided that the problem.For example, AT need not initiate another DAP migration, until receive from The response and the response of more early DAP migrations terminates.

Secondly, DAP is the data anchor for AT in RAN from AGW.DAP is preferably in the RS of AT.So as to work as needs When can obtain motility and quickly renewal.For example it is assumed that AGW needs to update the strategy for AT, and the change needs Carry out in the current communication sessions of AT.The change can be sent to DAP from AGW, and the change is subsequently relayed to AT by which To be updated rapidly.On the other hand, if DAP is not in the RS of AT, the change would be impossible to so easy to quickly enter Row updates.

Additionally, AT has first-hand information for its link circuit condition with each eBS in RS.Correspondingly, AT has more advantage It is whether sufficiently stable as DAP to determine the eBS for currently being communicated (i.e. FLSE).

In addition, AT auxiliary DAP switching than AN initiate DAP switching it is simpler, be included in institute's exchange message quantity with In realization.

Below with reference to Fig. 3 and Fig. 5.It is assumed that AT 44 moves to the overlay area 37 of eBS 36.Then, AT 44 and eBS 36 enters Row communication.So as to FLSEs of the eBS 36 as AT 44.

In the switching of the AT auxiliary described by the embodiment, AT can weigh before deciding whether to start DAP handoff procedures Measure and assess some criterions or situation.Mainly, AT is contemplated that whether the duration communicated with current FLSE has been reached and makes a reservation for Length.This be in order to avoid with the communication of FLSE be only it is provisional in the case of FLSE is appointed as into DAP.Additionally, opening Before the handoff procedure of beginning AT auxiliary, AT can determine that from the last time whether have passed through the predetermined time since switching.Its reason It is, it is undesirable to which AT excessively continually switches DAP, because frequent and unnecessary switching can cause to communication resource poor efficiency Consumption.It is equally important that AT can assess the communications link condition of each eBS, to decide whether to have reason to carry out DAP to cut Change.Certainly, allow AT DAP to be switched to the FLSE that AT has unfavorable communication condition with which, be unadvisable.

In the example it is assumed that being have the radio link situation that have passed through a certain amount of time and eBS 36 is determined After profit, AT 44 determines for DAP to switch to eBS 36 from eBS 34.In the following description, eBS 34 is referred to as into source DAP eBS.EBS 36 is referred to as into target DAP eBS.Handoff procedure starts from AT 44 and sends request message to target DAP eBS 36 (referred to herein as DAPMoveRequest message).The flow path of request message is represented by the reference number 52 illustrated in Fig. 5.Mesh Mark DAP eBS 36 may accept or deny the request, for example, determine according to by the congestion level for entering calling of eBS 36.

If target DAP eBS 36 receives request, target DAP eBS 36 for example, by using PMIPv4 agreements to AGW 32 sends PMIP- login request messages, updates the data attachment binding with AGW 32.Message flow is by illustrating in Fig. 5 Reference number 54 is representing.

AGW 32 is updated to confirm to bind by sending PMIP- registrations and replying message to target DAP eBS 36, in such as Fig. 5 Message flow 56 shown in.Hereafter, data tunnel can be set up via target DAP eBS 36 between AGW 32 and AT 44. PMIP- registrations reply message the life parameter for including data tunnel.Life parameter is used to prevent the appearance of following state, i.e., when AT 44 is still maintained to tunnel and is caused the invalid use to the communication resource when static.If AT 44 is after the life-span is reached The communication of maintenance activity, AT 44 is needed to need to expire in the life-span and send another DAPMoveRequest message with forward direction eBS 36.

After binding renewal process is completed, target DAP eBS 36 responds AT with DAPAssignment message 44, as shown in message flow path 58 in Fig. 5.To AT 44, DAPAssignment message notifies whether DAP switchings are successful.Additionally, DAPAssignment message mainly may include that AGW 32 is successfully made what PMIP being registered and being sent because of target DAP eBS 36 Timestamp, and the also residual life in binding data tunnel.If the number set by the timestamp of DAPAssignment message The timestamp of the DAPAssignment message that value is processed less than corresponding previous AT 44, then AT 44 is discardable should DAPAssignment message, i.e. abandon the message sent via flow path 58.Adopt in such a way to operate, can keep away Exempt from the race condition above described in Fig. 4.

On the other hand, if the timestamp via the DAPAssignment message of flow path 58 has nearest value, That is, higher than the value of any correspondent time of DAPAssignment message handled by previous AT 44, then AT 44 can be by target The data path routing label of eBS 36 is route for DAP.In addition, AT 44 can be by other the data path route marks to other eBS It is designated as non-DAP routes.At the same time, AT 44 can start the timer of itself being associated with the DAP routes of labelling recently, come The frequency of adjustment DAP switchings.As previously described, DAP switchings excessively had better not be continually carried out, for example, is only had in link circuit condition During minor variations.For example, frequent and unnecessary DAP switchings can affect the load of AGW 32.

Hereafter, the role of the DAP that target DAP eBS 36 notifies to have taken over AT 44 to all of eBS in the RS of AT 44. The notice is entered to the related entities in the RS of all eBS and AT 44 in the form of the Internet protocol tunnel (IPT)-notification message Row sends.One of them shows in target eBS 36 is sent to the message pathway 60 of session reference network controller (SRNC) 40 Go out.The IPT- notification messages sent via path 60 have multiple purposes.First, target DAP eBS 36 notifies other eBS mesh Mark DAP eBS 36 are current DAP now.Additionally, IPT- notification messages also include message sequence numbering and target DAP eBS 36 Timestamp attachment binding used in is updated the data with AGW 32 previously.

In order to allow SRNC 40 to confirm that eBS 36 is current DAP, SRNC 40 sends IPT- Notification Validations, in Fig. 5 Shown in message flow path 62.

Especially, as shown in the message flow path 66 in Fig. 5, notify to assume responsibility for DAP role institute to other eBS with aforesaid Differently, target eBS 36 is by sending IPT- notification messages to source DAP eBS 34, to notify to assume responsibility for working as to source DAP 34 The role of front DAP.IPT- notification messages notify source DAP eBS 34, and target eBS 36 is current DAP eBS.Equally, IPT- Notification message may include message sequence numbering and target DAP eBS 36 used in attachment binding is updated the data with AGW 32 Timestamp.

In order to allow source DAP eBS 34 to confirm that eBS 36 is current DAP, source DAP eBS 34 needs to send IPT- and notifies true Recognize message, as shown in message flow path 68 in Fig. 5.Optionally, IPT- notification acknowledgements may indicate that whether message sender is AT 44 current FLSE.After IPT- notification acknowledgements are received, target eBS 36 completes DAP handoff procedures.Hereafter, IP Stream of packets directly flows through eBS 36 by packet path 64 of flowing, rather than as shown in figure 3, is flowed road by packet 62 complications of footpath are through eBS 34.

Fig. 6 is shown to AT 44 it is determined that performed process is summarized during the DAP of AT auxiliary switches stream Cheng Tu.

Fig. 7 shows the message flow diagram of another embodiment of another kind of method of the DAP switchings of AT auxiliary.In the reality Apply in example, switch and initiated by AT but according to the request of infrastructure entities carrying out.

Fig. 7 is referred to reference to Fig. 3.It is assumed that eBS 34 be with AGW 40 carry out PMIP bindings for AT 44 most Entity afterwards.So, eBS 34 is the current DAP of AT 44.

Similar to described previously, in DAP switchings AT auxiliary or that AT is initiated, the eBS in the auxiliary RS of AT 44 is determining Which eBS in RS should be DAP.

There is communication or infrastructure entities request AT 44 to initiate various situations of DAP switchings.For example, current DAP (being eBS 34 in this case) can be transshipped because of calling.In order to mitigate congestion, any infrastructure entities (such as eBS 34 or 36) eBS can initiate handoff procedure to the requests of AT 44.

As another example, it is assumed that AT roams into the overlay area communicated with new eBS, the wherein new eBS with it is new AGW be associated, the new eBS needs to switch to set up PMIP connections via AGW, but regardless of whether new eBS is for AT FLSE.In this case, aforesaid any infrastructure or network entity can also ask AT 44 to initiate DAP switchings Process.

It is assumed that in this case, target DAP eBS 36 asks for DAP to be switched to eBS 36 from eBS 34 to AT 44.Under Face refers to Fig. 7.Target DAP eBS 36 can be carried out by being sent to the DAPMoveRequestRequest message of AT 44 please Ask, as shown in the message flow path 70 in Fig. 7.For example, the link ID being associated with IP packet routings can include In DAPMoveRequestRequest message, IP packet routings therein are associated with eBS 36.

AT 44 may accept or deny the request.If AT 44 refuses the request, AT 44 sends refusal to eBS 36 and disappears Breath.Alternatively, AT 44 can be not responding to eBS 36 to refuse the request by making default timer expire.

In embodiment above, it is determined that receiving or refusing in request process, it may be considered that several factors.It is assumed that The 36 current FLSE for AT 44 of eBS are not its DAP.If meeting aforesaid one group of predetermined condition, AT is acceptable from eBS The 34 DAP handover requests for being switched to eBS 36.On the other hand, for example, it is assumed that if AT 44 is not desired to use eBS 36 for a long time Used as FLSE, or communication conditions are unfavorable, then AT 44 is rejected by request.

If request is rejected, DAP handoff procedures terminate, without the change of DAP.That is, AT 44 passes through IP flow datas Path 62 (Fig. 3) and be continuing with eBS 34 as current DAP.

It is assumed that AT 44 receives the request.In this embodiment, by sending to EBS 36 via message flow path 72 DAPMoveRequest message, sends the acceptance to target eBS 36.

It should be noted that AT 44 should not be preset in the message timer set by send more than one in time dimension DAPMoveRequest message.Additionally, the AT auxiliary carried out under the request of infrastructure entities described in the embodiment DAP handoff procedures in, target eBS 36 should not send any DAPAssignment message, unless eBS 36 is received DAPMoveRequest message (the DAPMoveRequest message for for example being sent by message flow path 72).

Fig. 8 show to AT 44 it is determined that answer network entity request and carry out AT auxiliary DAP switch during institute The flow chart summarized by implementation procedure.

Hereafter DAP handoff procedures are substantially similar to the handoff procedure described in preceding embodiment.For clear and letter Bright purpose, the no longer remaining step to illustrating in Fig. 7 are further described.

Fig. 9 is illustrated for performing the hard-wired part of the device of handoff procedure described above.Circuit arrangement passes through Indicating, which can realize in AT or any communication entities (such as eBS or AGW) reference 90.

Device 90 includes the central data bus 92 for linking together some circuits.Circuit includes that (central authorities are processed CPU Device) or controller 94, receiving circuit 96, transtation mission circuit 98 and memory cell 100.

If device 90 is the ingredient of wireless device, receiving circuit and transtation mission circuit 96 and 98 may be connected to RF (radio frequency) circuit, but be not shown.Before sending to data/address bus 92, the signal that receiving circuit 96 pairs is received is carried out Process and buffer.On the other hand, before sending out from equipment 90,98 pairs of data from data/address bus 92 of transtation mission circuit are carried out Process and buffer.CPU/ controllers 94 perform the data management function of data/address bus 92, and also perform general data processing work( Can, including the command content of run memory unit 100.

Alternatively, different from the independent arrangement institute shown in Fig. 9, transtation mission circuit 98 and receiving circuit 96 can be CPU/ controls The ingredient of device processed 94.

Memory cell 100 includes one group of module and/or the instruction generally represented by reference 102.In the enforcement In example, modules/instructions mainly include handoff functionality 108.Handoff functionality 108 includes illustrating and describing for performing in Fig. 5-Fig. 8 Process step computer instruction or code.The specific instruction for being exclusively used in entity can optionally be come in handoff functionality 108 Realize.For example, if device 40 is the ingredient of AT, can be by the process for illustrating and describing in performing Fig. 6 and Fig. 8 The message preparation relevant with AT for illustrating in step and Fig. 5 and Fig. 7 and describing and the instruction encoding of process are to handoff functionality 108 In.Similarly, if device 40 is the ingredient of communication entity (such as eBS), the communication entity can be will be specific to Process step is encoded in handoff functionality 108.

In this embodiment, memory cell 100 is RAM (random access memory) circuit.Such as handoff functionality 108 Exemplary functions are software routines, module and/or data set.Memory cell 100 may be connected to another memory circuitry (not Illustrate), which can be volatibility or nonvolatile type.Alternatively, memory cell 100 can be made up of other circuit types, Such as：EEPROM (Electrically Erasable Read Only Memory), EPROM (EPROM), ROM (read-only storages Device), ASIC (special IC), disk, CD and other devices well known in the art.

It shall yet further be noted that described creative method can also be encoded into computer-readable instruction, the computer-readable refers to Making.In this description and in the appended claims, term " computer-readable medium " refers to participate in any processor that (CPU/ for such as, illustrating in the diagram of Fig. 9 and describe is controlled 94) device provides any medium of the instruction for performing.As it was previously stated, the medium can be storage class, and before may also be employed The form of the volatibility or non-volatile memory medium of face description, for example, the shape to the description of memory cell 100 in fig .9 Formula.The medium can also be transport-type, and may include that coaxial cable, copper conductor, optical cable, carrying can be carried by machine or meter Calculate the air interface of the sound wave, electromagnetic wave or light wave of the machine-readable signal for taking.Computer-readable medium can be separated with device 90 Computer product ingredient.

Finally, other changes can be carried out within the scope of the present invention.Except mentioned above, describe in conjunction with the embodiments Any other box, circuit and algorithm steps can be realized in hardware, software, firmware or its combination.The skill of this area Art personnel be readily apparent that, can make these and other change in form and details to which, without departing from the scope of the present invention and Spirit.

Claims (21)

1. a kind of method for being performed by access terminal in a wireless communication system, including：

Communicated with the first evolution base station, first evolution base station be configured to it is direct communicate with the access terminal, it is described First evolution base station is further configured to the data attachment point of the access terminal；

Communicated with the second evolution base station, second evolution base station is configured to direct communication with the access terminal and straight Connect and communicate with the data attachment point；

Judge after second evolution base station becomes the serving BS of the access terminal access terminal whether with Second evolution base station has communicated at least predetermined time；

For being estimated with the link condition of first evolution base station and second evolution base station；And

Based on the judgement and the assessment, initiated the data attachment point from the first evolution base by the access terminal Station is switched to second evolution base station, wherein, it is described to initiate to wrap during operation is based further on the set of routes of the access terminal Second evolution base station is included, the set of routes includes the communication entity with the air interface route with the access terminal, And by the set of routes, the communication meeting of the access terminal is maintained when the set of routes includes second evolution base station Words.

2. method according to claim 1, also including one group of criterion for assessing the link condition and described meeting The switching is initiated after one group of criterion.

3. method according to claim 1, sends out to second evolution base station in being additionally included in the initiation handoff procedure Send request message.

4. method according to claim 1, receives from second evolution base station before being additionally included in the initiation switching Handover request.

5. method according to claim 1, receives from second evolution base station before being additionally included in the switching and specifies The notice of data attachment point.

6. method according to claim 5, the timestamp being additionally included in the notice of specified data attachment point.

7. it is a kind of by be configured to the access terminal in communication system carry out direction communication target evolution base station perform side Method, the communication system include being configured to drill with the access terminal and also with the source of the target evolution base station direction communication Enter base station, methods described includes：

Handover request message is received from the access terminal, the handover request message is for data attachment point is drilled from the source Enter base station and be switched to the target evolution base station, wherein, the handover request message is based on to the source evolution base station and institute The assessment for stating the link condition of target evolution base station and the service base for becoming the access terminal in the target evolution base station Predetermined length is exceeded with the persistent period of the communication of the target evolution base station after standing；

After the handover request message is received, received from the source evolution base station described in will being sent to before the handover The first data transmission of access terminal；

The first data transmission is forwarded to into the access terminal；

Receive in the case where the source evolution base station is not related to after the handoff and will be sent to the second of the access terminal Data transfer；And

Second data transfer is forwarded to into the access terminal,

Wherein, the set of routes that the operation for receiving the handover request message is based further on the access terminal includes institute Target evolution base station is stated, the set of routes includes the communication entity with the air interface route with the access terminal, and By the set of routes, the communication meeting of the access terminal is maintained when the set of routes includes the target evolution base station Words.

8. it is a kind of to configure the access terminal for operating in a wireless communication system, including：

For the module communicated with the first evolution base station, first evolution base station is configured to direct logical with the access terminal Letter, first evolution base station are further configured to the data attachment point of the access terminal；

For the module communicated with the second evolution base station, second evolution base station is configured to direct with the access terminal Communicate and directly communicate with the data attachment point；

For judging after second evolution base station becomes the serving BS of the access terminal access terminal whether Communicated the module of at least predetermined time with second evolution base station；

For providing the module of the assessment to first evolution base station and the link condition of second evolution base station；

For storing the module of set of routes, wherein the set of routes is included with the air interface route with the access terminal Communication entity；

For based on the judgement and the assessment and being based further on the set of routes of the access terminal and including described the Two evolution base stations, are initiated for the data attachment point to be switched to described second from first evolution base station by the access terminal The module of evolution base station, wherein by the set of routes, remaining described when the set of routes includes second evolution base station The communication session of access terminal.

9. access terminal according to claim 8, also include one group of criterion for providing the link condition and The module of the switching is initiated after meeting one group of criterion.

10. access terminal according to claim 8, is also included for drilling to described second in the handoff procedure is initiated Enter the module that base station sends request message.

11. access terminals according to claim 8, also include for before the switching is initiated from second evolution Base station receives the module of handover request.

12. access terminals according to claim 8, are also included for before the handover from second evolution base station Receive the module of the notice for specifying data attachment point.

13. access terminals according to claim 12, wherein, the notice of the specified data attachment point also includes the time Stamp.

A kind of 14. target evolution base stations for being configured to direction communication is carried out with the access terminal in communication system, the communication System includes being configured to the access terminal and the source evolution base station also with the target evolution base station direction communication, described Target evolution base station includes：

For receiving for data attachment point is switched to the target evolution from the source evolution base station from the access terminal The module of the handover request message of base station, wherein, the handover request message is based on to the source evolution base station and the mesh Mark evolution base station link condition assessment and the target evolution base station become the access terminal serving BS it Predetermined length is exceeded with the persistent period of the communication of the target evolution base station afterwards and has sent；

For, after the handover request message is received, receiving and will be sent to from the source evolution base station before the handover The module of the first data transmission of the access terminal；

For the first data transmission received from the source evolution base station to be forwarded to the module of the access terminal；

The access terminal will be sent to for receiving in the case where the source evolution base station is not related to after the handoff The module of the second data transfer；And

For second data transfer to be forwarded to the module of the access terminal,

Wherein, the set of routes of the access terminal includes the target evolution base station, the set of routes include with it is described The communication entity of the air interface route of access terminal, and by the set of routes, when the set of routes includes the target The communication session of the access terminal is maintained during evolution base station.

A kind of 15. access terminals for being configured to operate in a wireless communication system, including：

Processor；And

Circuit, which is coupled to the processor, is used for：

Communicated with the first evolution base station, first evolution base station be configured to it is direct communicate with the access terminal, it is described First evolution base station is further configured to the data attachment point of the access terminal；

Communicated with the second evolution base station, second evolution base station is configured to direct communication with the access terminal and straight Connect and communicate with the data attachment point；

Judge after second evolution base station becomes the serving BS of the access terminal access terminal whether with Second evolution base station has communicated at least predetermined time；

Assess the link condition of first evolution base station and second evolution base station；And,

Based on the judgement and the assessment, initiated the data attachment point from the first evolution base by the access terminal Station is switched to second evolution base station, wherein, it is described to initiate to wrap during operation is based further on the set of routes of the access terminal Second evolution base station is included, the set of routes includes the communication entity with the air interface route with the access terminal, And by the set of routes, the communication meeting of the access terminal is maintained when the set of routes includes second evolution base station Words.

16. access terminals according to claim 15, wherein, the circuit and the processor are additionally operable to assess the chain One group of criterion of travel permit part and the switching is initiated after one group of criterion is met.

17. access terminals according to claim 15, wherein, the circuit and the processor are additionally operable to initiating described Request message is sent to second evolution base station in handoff procedure.

18. access terminals according to claim 15, wherein, the circuit and the processor are additionally operable to initiating described Handover request is received from second evolution base station before switching.

19. access terminals according to claim 15, wherein, the circuit and the processor are additionally operable in the switching Receive the notice for specifying data attachment point before from second evolution base station.

20. access terminals according to claim 19, wherein, the notice of the specified data attachment point also includes the time Stamp.

A kind of 21. target evolution base stations for being configured to direction communication is carried out with the access terminal in communication system, the communication System includes being configured to the access terminal and the source evolution base station also with the target evolution base station direction communication, described Target evolution base station includes：

Processor；And

Circuit, which is coupled to the processor, is used for：

Receive for data attachment point is switched to the target evolution base station from the source evolution base station from the access terminal Handover request message, wherein, the handover request message is based on to the source evolution base station and the target evolution base station Link condition assessment and after the target evolution base station becomes the serving BS of the access terminal with the mesh The persistent period of the communication of mark evolution base station has exceeded predetermined length and has sent；

After the handover request message is received, received from the source evolution base station described in will being sent to before the handover The first data transmission of access terminal；

The first data transmission received from the source evolution base station is forwarded to into the access terminal；

Receive in the case where the source evolution base station is not related to after the handoff and will be sent to the second of the access terminal Data transfer；And

Second data transfer is forwarded to into the access terminal, and

Wherein, the set of routes of the access terminal includes the target evolution base station, the set of routes include with it is described The communication entity of the air interface route of access terminal, and by the set of routes, when the set of routes includes the target The communication session of the access terminal is maintained during evolution base station.