CN101653026A - 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 the data attachment point

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

Present patent application requires the U.S. Provisional Application No.60/910 respectively on April 6th, 2007, on April 13rd, 2007 and submission on June 12nd, 2007,628,60/911,858 and 60/943,459 priority, these provisional application have transferred the application's assignee, so incorporate the application clearly by reference into.

Technical field

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

Background technology

In telecommunications, especially in the radio communication, communication environment is not static, but dynamic.In mobile communication is provided with, can move to another position from a position at different time points such as some communication entities of access terminal (AT).

With reference to Fig. 1, it illustrates the sketch that example communication system is described.In the following description, used the term that is associated with Ultra-Mobile Broadband (UMB) system.The basic terms of UMB system and operating principle can find from the publication that is called " Interoperability Specification " 3GPP2-A.S0020 that the third generation partner program 2 (3GPP2) that telecommunications industry association (TIA) sets up is published.As shown in Figure 1, in the inside of Radio Access Network (RAN) 12, for example, in Ultra-Mobile Broadband (UMB) system, AT 14 inserts backbone network 16 via evolution base station (eBS) 18 with wireless mode in this system.EBS 18 between AT 14 and IAD (AGW) 20 as the exchanges data entity.AGW 20 directly inserts backbone network 16.For example, backbone network 16 can be the internet.

In Fig. 1, eBS 18 as the data attachment point (Data Attachment Point) of AT 14 (DAP).More specifically, for example, have forward link traffic binding (binding) as eBS 18 and the AGW 20 of DAP, as, operate according to proxy-mobile IP (PMIP) agreement that the Internet engineering duty group (IETF) is announced.According to the PMIP agreement, AGW 20 sends to DAP (being eBS 18 in this example) with the forward link data business, and DAP is sent to data service AT 14 then.EBS 18 as DAP carries out the 20 last network entities of binding with AGW.

In wireless environment, AT 14 moves.That is, AT 14 can move to another position in same RAN 12 from a position, perhaps moves to different RAN.

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

In Fig. 2, suppose that the AT 14 that originally communicates by letter with eBS 18 leaves eBS 18 now and begins to communicate with eBS 22.The forward link service eBS (FLSE) that now eBS 22 is called AT 14 is because eBS 22 directly communicates also swap data with AT 14.Yet, with AGW 20 still without any Binding Update.That is to say that the network entity of binding at last with AGW 20 remains eBS18, and hereafter with AGW 20 without any Binding Update.Similarly, eBS 18 is still as DAP.In this case, will send to from the data of AGW 20 in this case, route data to AT 14 then, arrive eBS 20 as FLSE as the eBS 18 of DAP.Route is carried out in 24 pairs of packets from AGW 20 to AT 14 according to the data path shown in Fig. 2.

Even AT 14 has roamed into outside the overlay area that eBS 18 served, eBS 18 remains the DAP of AT 14.Its reason is, in wireless setting, depends on the mobility of AT 14, and eBS 18 might become the FLSE of AT 14 once more.For example, AT 14 may be positioned on the boundary line of eBS 18 and eBS 22 the two overlay area that provide.Like this, AT 14 may only communicate with eBS 22 provisionally.Yet if the communication between AT 14 and the eBS 22 is not interim, at least from the angle of utilization of homeward voyage, it is not effective utilization to the communication resource that the data path 24 by complications comes the route packet.In addition, this has also influenced the grouped data delay.Alternatively, DAP preferably switches to eBS 22 from eBS 18.Be used for this DAP and switch, eBS 22 at first needs to carry out the forward link traffic binding with AGW 20.After completing successfully the forward link traffic binding procedure, eBS 22 becomes current DAP.Then, packet is routed to AT 14 via eBS 22 from AGW 20, shown in the data path among Fig. 2 26.Based on specified criteria DAP is switched to eBS 22 from BS 18, for example, after communicating by letter of having determined that AT and eBS 22 carry out continued predetermined amount of time.

So far, switching or the selection (being called DAP switches) to DAP is that AN initiates mostly.In the switching that AN initiates, handoff procedure is transparent for AT 14.Yet, do not know at AN 14 under the situation of switching and can go wrong.For example, expection DAP the possibility of result is the DAP of non-expectation.Especially like this, wherein various communication entities are the phase mutually synchronization not under asynchronous environment.Return Fig. 2, suppose that once more AT 14 is positioned on the border of eBS 18 and eBS 22 the two overlay area.In the switching that AN initiates, for example sense the existence of AT 14 via downlink signal strength, eBS 18 and eBS22 attempt by becoming DAP with AGW 20 registration forward link binding.Suppose that also AT 14 is positioned at the overlay area that eBS 18 provides fully, thereby eBS 18 should be AT 14 optimal DAP.Yet, if the registration message that sends between AGW 20 and the eBS 22 and receive is faster than the registration message between AGW 20 and the eBS 18, eBS 22 may be had precedence over eBS 18 and be appointed as DAP, just in time opposite with expectation.The recovery that the DAP of wrong appointment is carried out, even be not fatal to the communication session that relates to, it requires extra signaling and message transmission, thereby has unnecessarily hindered the communication resource.

Correspondingly, need provide to have more high accuracy and deterministic DAP specified scheme, thereby can more effectively utilize the communication resource.

Summary of the invention

In communication system, gateway entity is linked to a plurality of communication entities, and these a plurality of communication entities then can be operated and access terminal and communicate, described access terminal at first need with described communication entity in one set up data attachment point (DAP).Described accessing terminal initiates described DAP is switched to another communication entity from a communication entity.Carrying out before described DAP switches, described accessing terminal can be considered multiple factor, such as and the link circuit condition between a plurality of communication entity, the last DAP time since switching, and with current communication entity between duration of communicating by letter.For fear of any race condition that a plurality of communication entities are registered as DAP occurring, accessing terminal can be with reference to the timestamp that receives message from a plurality of communication entities.In addition, a plurality of communication entities can also be at current DAP login state interchange messages.

According to the detailed description that provides below in conjunction with accompanying drawing, those skilled in the art will know feature of the present invention and advantage, and in the accompanying drawings, identical Reference numeral is represented identical parts.

Description of drawings

Fig. 1 is the sketch that example communication system is shown;

Fig. 2 illustrates ambulant another sketch that accesses terminal in the communication system;

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

Fig. 4 shows the call flow chart of the different communication inter-entity message stream of operating in the asynchronous system, and DAP wherein switches does not have AT auxiliary;

Fig. 5 shows the call flow chart of the different communication inter-entity message stream of operating in the synchro system, and it is that AT is auxiliary that DAP wherein switches;

Fig. 6 shows the flow chart of the process that AT carries out in determining the process that the auxiliary DAP of AT switches;

Fig. 7 shows the call flow chart of message flow between the different communication entity of operating in synchro system, wherein DAP switches under the request that is subjected to auxiliary but the communication entity in a plurality of communication entities of AT and carries out;

Fig. 8 shows the flow chart of process performed in the process that the auxiliary DAP of definite AT that carries out under one the request of AT in should a plurality of network entities switches; And

Fig. 9 is the schematic diagram that is used to carry out its hard-wired part of device of DAP handoff procedure according to exemplary embodiment.

Embodiment

For making those skilled in the art can realize or use the present invention, provided description below.For purpose of explanation, some details have been set forth in the following description.Should be appreciated that those of ordinary skills will appreciate that, can realize the present invention under the situation of not using these details.In other example,, do not elaborate some known structure and processes for fear of because of inessential details causes vague description to the present invention.Therefore, the present invention is not limited to shown embodiment, but consistent with the widest scope of disclosed principle of the application and feature.

In addition, in the following description, for the purpose of simple and clear, the term that has used Ultra-Mobile Broadband (UMB) technology announced by third generation partner program 2 (3GPP2) with telecommunications industry association (TIA) to be associated.Should be emphasized that the present invention also is applicable to other technology, such as technology that relates to code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), OFDM (OFDMA) etc. and the standard that is associated.

Referring now to Fig. 3, its according to an exemplary embodiment of the present schematically illustrated and relations between a plurality of communication entities of arranging.

In Fig. 3, whole communication system briefly adopts Reference numeral 30 to represent.In communication system 30, IAD (AGW) 32 is linked to a plurality of evolution base stations (eBS), and wherein two are shown eBS 34 and eBS 36.EBS 34 and eBS 36 can be installed among same access network (AN) or the different AN.In this example, eBS 34 and 36 is respectively the part of AN 41 and AN 43.Among AN 41 and the AN 43 each can comprise one or more eBS and other entity.For clarity and conciseness, in Fig. 3, only illustrate and have an eBS for each AN.Among the embodiment shown in Figure 3, eBS 34 user in overlay area 35 provide wireless access.Similarly, eBS 36 provides the wireless access in the overlay area 37.AGW 32 has to the link of backbone network 38, and backbone network 38 for example can be the Internet.In another example, backbone network 38 can be the Intranet in the close network.

Session reference network controller (SRNC) 40 is linked to AGW 32.SRNC 40 has multiple function.For example, SRNC 40 provides authentication function for access terminal (AT) (example is AT 44 as shown in Figure 3).In addition, SRNC 40 stores the communication session of AT 44 for any new eBS for preparing to communicate by letter with AT 44.Usually, SRNC 40 also controls the paging of idle condition.

Suppose that AT 44 can move, and comprises AN 41 and AN 43 between a plurality of radio nets.In order to allow AT 44 insert backbone network 38, AT 44 at first needs the data attachment point (DAP) of foundation and communication entity (for example eBS34 or eBS 36).In this explanation and claims, term " data attachment point " is interpreted as directly or indirectly to network gateway or from the communication entity of network gateway grappling data.As shown in Figure 3, for example, if eBS 34 is appointed as DAP, then from the data of backbone network 38 by after the gateway entity (being AGW 32 in this case), before via data path 62 other communication entities of arrival (for example eBS 36), be used as communication entity (the being eBS 34 in this case) grappling of DAP.In this example, eBS 34 via data path 62 directly from AGW 32 grappling data.It is also set up for reverse data flow.That is to say that the data that receive from other communication entity arrive before the gateway entity by the DAP grappling.

The DAP that initiates at AN carries out in the configuration of appointment, if satisfied certain criterion, then each among eBS34 and the eBS 36 all carried out the DAP assignment procedure.For example, when eBS 34 became the forward link service eBS (FLSE) of AT 44, it can begin the DAP assignment procedure.Therefore, if eBS 34 is current FLSE, then eBS 34 sends to AGW 32 with login request message.Afterwards, the process that proxy-mobile IP (PMIP) agreement of being announced according to the Internet engineering duty group (IETF) provides, AGW 32 and eBS 34 carry out Binding Update.

Suppose that communication system 30 is synchro system.That is, all communication entities (such as AGW 38, eBS34 and eBS 36 etc.) are operated according to main time reference.For example, primary standard can be global positioning system (GPS) time.In this case, predefined DAP log-in protocol can be set, for example by allowing that DAP is handled and ratifies to be in the request that arrives at first, till next one approval.Yet, if system 30 can go wrong when being asynchronous system.Because lack main time reference, can produce wrong DAP and specify.

Come with reference to figure 3 below in conjunction with Fig. 4, it shows the message flow sequence between the different entities.Suppose that system 30 is to use the system of the DAP handover scheme of AN initiation.Suppose that also AT 44 moves to overlay area 35 and 37 overlapping regions 46 at its binding site place.EBS 34 senses the existence of AT 44, sends login request message at time t1 to AGW 32, attempts to be registered as to AGW 32 DAP of AT 44, shown in the message flow among Fig. 4 48.Suppose in the system 30 rule that adopts " service earlier first ".Under this rule, at first send the eBS 34 of login request message, expectation becomes the DAP of AT 44.

When AT 44 is arranged in covering overlapping area 46, suppose that eBS 36 also senses the existence of AT 44.In this example, eBS 36 also sends login request message to AGW 32 at time t2, shown in the message flow among Fig. 4 50.Here, t2 is later than t1.

Based on some reason, the message that sends via message flow 50 arrives AGW 32 early than the message of message flow 48.More specifically, the message that eBS 36 sends arrives AGW 32 at time t3, and the message that corresponding eBS 34 sends arrives AGW 32 at time t6.Under this situation, time t6 is later than time t3.For example, in eBS 36 has the communication environment of better communication conditions than eBS 34 aforementioned circumstances can appear.

For AGW 32, because it receives registration message at time t3 from eBS 36, according to " service earlier first " rule, AGW 32 ratifies these requests and sends the message that succeeds in registration at time t4 to eBS 36, and arrives eBS 36 at time t5.Thereby eBS 36 successfully is registered as the DAP of AT 44.

Suppose that AGW 32 also receives login request message at time t6 from eBS 34.Time t6 is later than time t5, and wherein t5 is eBS 36 successfully is registered as time from the DAP of eBS 34 to AGW 32.

Depend on the log-in protocol that realizes among the AGW 32, AGW 32 may suppose that eBS 34 wants to replace current DAP eBS 36 as new DAP.

Then, AGW 32 sends the answer of succeeding in registration at time t7 to eBS 34, and it arrives eBS 34 at time t8.Then, eBS 34 is as new DAP.

In the example in front, being to want eBS 34 to become DAP at the beginning, that is, is not to be to want eBS 36 to bear middle DAP role.Such DAP specifies and may have problems.Even supposition is to the not infringement of data of communication session, this type of DAP specifies the professional route that can cause lasting and poor efficiency, thereby has unnecessarily taken the communication resource.Any trial of carrying out the mistake recovery will inevitably require extra time and resource and extra complexity.

Although it shall yet further be noted that eBS 34 and eBS 36 can have timestamp via message flow 48 and the 50 PMIP binding messages that send respectively and prevent out of order Binding Update.Yet because system 30 moves asynchronously, timestamp may be invalid for the function of carrying out them.Reason is that each communication entity in asynchronous system (for example eBS 34 and eBS 36) moves according to the time reference of himself.Send to timestamp on the binding message of AGW 32 not at main time reference but at the benchmark of single entity.The time reference of a plurality of entities can have big side-play amount each other.Therefore, previously described problem still can occur.

Fig. 5 shows AT message flow diagram auxiliary or the DAP handover scheme that AT initiates according to an exemplary embodiment of the present.Hereinafter, use term " AT assists " and " AT initiates " interchangeably.

Come with reference to figure 5 in conjunction with Fig. 3 now.Supposing that AT 44 is initial communicates with eBS 34, and wherein eBS 34 carries out the last entity that PMIP binds with AGW 40.Thereby eBS 34 is current DAP of AT 44.

AN 44 has set of routes (RS) in its memory.RS comprises a group communication entity, for example eBS 34 and eBS 36, and it has the air interface route with AT 44, and each entity can be handled with 44 pairs of link layer packet of AT and IP grouping carrying out tunnel among the RS whereby, and vice versa.In AT DAP auxiliary or that AT initiates switched, the communication entity among the AT 44 auxiliary RS decided which entity among the RS should be DAP.

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

At first, as mentioned before, in asynchronous system (for example front system shown in Figure 4) race condition can appear.The auxiliary DAP of AT switches more can avoid this problem.For example, AT does not need to initiate another DAP migration, finishes up to the response and this response that receive from DAP migration early.

Secondly, DAP is from the data anchor that is used for AT of AGW among the RAN.DAP is preferably among the RS of AT.Thereby, when needs, can obtain flexibility and renewal fast.For example, suppose that AGW need upgrade the strategy that is used for AT, and this variation need be carried out in the current communication session of AT.This variation can send to DAP from AGW, and it should change relaying subsequently and give AT to upgrade rapidly.On the other hand, if DAP not in the RS of AT, this variation can not be upgraded so easily and apace.

In addition, AT has first-hand information for the link circuit condition of each eBS among itself and the RS.Correspondingly, AT has more advantage and determines that whether enough stable the current eBS that communicates (being FLSE) as DAP.

In addition, the auxiliary DAP of AT switches the DAP that initiates than AN and switches simplyr, is included in that institute exchanges messages quantitatively and in realization.

Below with reference to Fig. 3 and Fig. 5.Suppose that AT 44 moves to the overlay area 37 of eBS 36.Then, AT 44 communicates with eBS 36.Thereby eBS 36 is as the FLSE of AT 44.

In the auxiliary switching of the described AT of this embodiment, whether AT begins can weigh and assess some criterion or situation before the DAP handoff procedure in decision.Mainly, AT can consider whether the duration that communicates with current FLSE has reached predetermined length.This is for fear of only being under the provisional situation FLSE to be appointed as DAP with communicating by letter of FLSE.In addition, before the auxiliary handoff procedure of beginning AT, AT can determine whether passed through preset time since the last time switching.Its reason is, does not wish that AT switches DAP too continually, because frequent and unnecessary switching can cause the consumption to communication resource poor efficiency.It is also important that AT can assess the communications link condition of each eBS, whether have reason to carry out DAP with decision and switch.Certainly, allowing AT that DAP is switched to AT has unfavorable communication condition with it FLSE, is unadvisable.

In this example, suppose after the radio link situation of having determined to have passed through a certain amount of time and eBS 36 is favourable that the AT44 decision switches to eBS 36 with DAP from eBS 34.In the following description, eBS 34 is called source DAP eBS.EBS 36 is called target DAP eBS.Handoff procedure starts from AT 44 and sends a request message (being called DAPMoveRequest message here) to target DAP eBS 36.The flow path of request message is by 52 expressions of the reference number shown in Fig. 5.Target DAP eBS 36 can accept or refuse this request, for example, determines according to the congestion level that enters calling by eBS 36.

If target DAP eBS 36 accepts request, then target DAP eBS 36 sends the PMIP-login request message by for example adopting the PMIPv4 agreement to AGW 32, upgrades with the data of AGW 32 and adheres to binding.Message flow is represented by the reference number shown in Fig. 5 54.

AGW 32 confirms Binding Update by send PMIP-registration answer message to target DAP eBS 36, shown in the message flow among Fig. 5 56.After this, can between AGW32 and AT 44, set up data tunnel via target DAP eBS 36.Reply the life parameter that comprises data tunnel in the message in the PMIP-registration.Life parameter is used to prevent the appearance of following state, promptly still the tunnel is kept when AT 44 is static and is caused invalid use to the communication resource.If AT 44 needs to keep movable communication after arriving the life-span, AT 44 need expire in the life-span and send another DAPMoveRequest message with forward direction eBS 36.

After having finished the Binding Update process, target DAP eBS 36 responds AT 44 with DAPAssignment message, shown in message flow path among Fig. 5 58.Whether DAPAssignment message is switched successful to AT 44 notice DAP.In addition, DAPAssignment message can comprise that mainly AGW 32 carries out the timestamp that the PMIP registration is sent because of success to target DAP eBS 36, and the residual life that also has the binding data tunnel.If the set numerical value of the timestamp of DAPAssigmnent message is lower than the timestamp of the DAPAssignment message of corresponding previous AT 44 processing, then AT 44 discardable these DAPAssignment message promptly, abandon the message that sends via flow path 58.Adopt in such a way and operate, can avoid the race condition described in the prior figures 4.

On the other hand, if the timestamp via the DAPAssignment message of flow path 58 has nearest value, that is, be higher than the value of the previous AT 44 any correspondent time of DAPAssignment message of handling, then AT 44 can be the DAP route with the data path routing label to target eBS 36.In addition, AT 44 can be non-DAP route with other data path routing label to other eBS.Meanwhile, AT 44 can start self the timer that is associated with the DAP route of mark recently, adjusts the frequency that DAP switches.As previously described, had better not carry out DAP too continually and switch, for example when link circuit condition only has minor variations.For example, frequent and unnecessary DAP switches the load that can influence AGW 32.

After this, target DAP eBS 36 all eBS notices in the RS of AT 44 have been taken over the role of the DAP of AT 44.This notice sends with the related entities of form in the RS of all eBS and AT 44 of the Internet protocol tunnel (IPT)-notification message.One of them sends at target eBS 36 shown in the message pathway 60 of session reference network controller (SRNC) 40.The IPT-notification message that sends via path 60 has a plurality of purposes.At first, to notify other eBS target DAP eBS 36 be current DAP to target DAP eBS 36 now.In addition, the IPT-notification message also comprise message sequence numbering and target DAP eBS 36 formerly with AGW 32 more new data adhere to the timestamp that uses in the binding.

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

Especially, shown in the message flow path among Fig. 5 66, born DAP role institute differently with aforesaid to other eBS notice, target eBS 36 comes to have born to source DAP 34 notices the role of current DAP by sending the IPT-notification message to source DAP eBS 34.IPT-notification message notification source DAP eBS 34, target eBS 36 is current DAP eBS.Equally, the IPT-notification message can comprise message sequence numbering and target DAP eBS 36 with AGW 32 more new data adhere to the timestamp that uses in the binding.

In order to allow source DAP eBS 34 confirm that eBS 36 is current DAP, source DAP eBS 34 needs to send the IPT-notification acknowledgement, shown in message flow path among Fig. 5 68.Randomly, but the IPT-notification acknowledgement Indication message transmit leg current FLSE that whether is AT 44.After receiving the IPT-notification acknowledgement, target eBS 36 finishes the DAP handoff procedure.After this, and as shown in Figure 3, by the packet path 62 rather than tortuous through eBS 34 of flowing, the IP stream of packets directly flows through eBS 36 by the packet path 64 of flowing.

Fig. 6 shows the flow chart that performed process is summarized in determining the process that the auxiliary DAP of AT switches to AT 44.

Fig. 7 shows the message flow diagram of another embodiment of the another kind of method that the auxiliary DAP of AT switches.In this embodiment, switching is initiated by AT but is carried out according to the request of infrastructure entities.

Come with reference to figure 7 below in conjunction with Fig. 3.Suppose that eBS 34 is the last entities that are used for AT 44 that carry out the PMIP binding with AGW 40.Like this, eBS 34 is current DAP of AT 44.

It is described to be similar to preamble, and in AT DAP auxiliary or that AT initiates switched, it should be DAP that the eBS among the AT 44 auxiliary RS decides which eBS among the RS.

Exist communication or infrastructure entities request AN 44 to initiate the multiple situation that DAP switches.For example, current DAP (being eBS 34 in this case) can transship because of calling.Congested in order to alleviate, any infrastructure entities (for example eBS 34 or eBS 36) can be initiated handoff procedure to AT 44 requests.

As another example, suppose that AT roams into the overlay area of communicating by letter with new eBS, wherein this new eBS is associated with new AGW, and this new eBS need switch via AGW and sets up PMIP and connect, and no matter whether new eBS is the FLSE that is used for AT.In this case, aforesaid any infrastructure or network entity also can ask AT 44 to initiate the DAP handoff procedure.

Suppose that in this case target DAP eBS 36 switches to eBS 36 with DAP from eBS 34 to AT 44 requests.Below with reference to Fig. 7.Target DAP eBS 36 can ask by the DAPMoveRequestRequest message that sends to AT 44, shown in the message flow path among Fig. 7 70.For example, the link ID that is associated with IP grouped data route can be included in the DAPMoveRequestRequest message, and IP grouped data route wherein is associated with eBS 36.

AT44 can accept or refuse this request.If AT 44 these requests of refusal, then AT44 sends refuse information to eBS36.Alternatively, AT 44 can not respond eBS 36 by making default timer expiration and refuses this request.

Among the embodiment as the front, still refuse to consider several factors in the request process in definite acceptance.Suppose eBS 36 current for the FLSE of AT 44 be not its DAP.If satisfy aforesaid one group of predetermined condition, then AT can accept to switch to from eBS 34 the DAP handoff request of eBS 36.On the other hand, for example, suppose that perhaps communication conditions is unfavorable if AT 44 does not think to use for a long time eBS 36 as FLSE, then AT 44 can refuse request.

If request is rejected, then the DAP handoff procedure finishes, and does not have the variation of DAP.That is, AT 44 continues to use eBS 34 as current DAP by IP flow data path 62 (Fig. 3).

Suppose that AT 44 accepts this request.In this embodiment, by sending DAPMoveRequest message to EBS36, send this acceptance to target eBS 36 via message flow path 72.

Should be noted that the DAPMoveRequest message that sends in the set time dimension of timer that AT 44 is not taken in the message to be preset more than one.In addition, in the DAP handoff procedure that the AT that carries out under the request of the infrastructure entities described in this embodiment assists, target eBS 36 should not send any DAPAssignment message, unless eBS 36 receives DAPMoveRequest message (for example DAPMoveRequest message that sends by message flow path 70).

Fig. 8 shows AT 44 is carried out the flow chart that performed process is summarized in the process that the auxiliary DAP of AT switches determining to answer the request of network entity.

After this DAP handoff procedure is similar to the handoff procedure of describing among the previous embodiment in fact.For clear and simple and clear purpose, no longer the remaining step shown in Fig. 7 is further described.

Fig. 9 illustrates a hard-wired part that is used to carry out as the device of above-mentioned handoff procedure.Circuit arrangement indicates that by Reference numeral 90 it can be realized in AT or any communication entity (for example eBS or AGW).

Device 90 comprises the central data bus 92 that some electrical chains are connected together.Circuit comprises CPU (central processing unit) or controller 94, receiving circuit 96, transtation mission circuit 98 and memory cell 100.

If installing 90 is parts of wireless device, then receiving circuit and transtation mission circuit 96 and 98 can be connected to RF (radio frequency) circuit, but do not illustrate in the drawings.Before sending to data/address bus 92, receiving circuit 96 is handled to the received signal and is cushioned.On the other hand, before slave unit 90 sent out, 98 pairs of data from data/address bus 92 of transtation mission circuit were handled and are cushioned.CPU/ controller 94 is carried out the data management function of data/address bus 92, and also carries out general data processing function, comprises the command content of run memory unit 100.

Replacedly, different with the independent layout institute shown in Fig. 9, transtation mission circuit 98 and receiving circuit 96 can be the parts of CPU/ controller 94.

Memory cell 100 comprises a pack module and/or the instruction of briefly being represented by Reference numeral 102.In this embodiment, modules/instructions mainly comprises handoff functionality 108.Handoff functionality 108 comprises the computer instruction or the code of the treatment step that is used for shown in execution graph 5-Fig. 8 and describes.The specific instruction that is exclusively used in entity can optionally realize in handoff functionality 108.For example, are parts of AT if install 40, then can be used for execution graph 6 with shown in Fig. 8 with the treatment step of describing and Fig. 5 with shown in Fig. 7 and the message of describing relevant with AT is prepared and the command coding of processing to handoff functionality 108.Similarly, are parts of communication entity (for example eBS) if install 40, then the treatment step that is exclusively used in this communication entity can be encoded in the handoff functionality 108.

In this embodiment, memory cell 100 is RAM (random access memory) circuit.Exemplary functions such as handoff functionality 108 is software routines, module and/or data set.Memory cell 100 can be connected to another memory circuitry (not shown), and it 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 memory), ASIC (application-specific integrated circuit (ASIC)), disk, CD and other device well known in the art.

It shall yet further be noted that and described creative method can also be encoded into computer-readable instruction, carry on this computer-readable instruction any computer-readable medium known in the art.In this specification and appending claims, term " computer-readable medium " refer to participation to any processor (such as, shown in the diagram of Fig. 9 and the CPU/ controller of describing 94) any medium of providing instruction to be used to carry out.As previously mentioned, this medium can be a storage class, and also can adopt the form of previously described volatibility or non-volatile memory medium, for example, in Fig. 9 to the form of the description of memory cell 100.This medium can also be a transport-type, and the air interface that can comprise coaxial cable, copper conductor, optical cable, carry sound wave, electromagnetic wave or the light wave that can carry the signal that is read by machine or computer.Computer-readable medium can be and the part that installs 90 computer products that separate.

At last, in protection scope of the present invention, can carry out other change.Except mentioned above, any other box, circuit and the algorithm steps of Miao Shuing can be implemented in hardware, software, firmware or its combination in conjunction with the embodiments.It will be apparent to one skilled in the art that and to make these and other change to it in form and details, and do not deviate from scope and spirit of the present invention.

Claims (41)

1, a kind of by the method for operating in communication system that accesses terminal, comprising:

Set up data attachment point with first communication entity;

Communicate with the second communication entity;

Assessment to one group of predetermined condition of described first communication entity and second communication entity is provided; And

Initiate described data attachment point is switched to described second communication entity from described first communication entity based on described assessment.

2, method according to claim 1 also is included in and initiates to communicate with described second communication entity after preset time before the described switching.

3, method according to claim 1, also be included in initiate to allow before the described switching to switch from the last time since through time enough.

4, method according to claim 1 also comprises one group of criterion that a described group communication condition is provided, and initiates described switching after satisfying described one group of criterion.

5, method according to claim 1 also is included in and initiates to send a request message to described second communication entity in the described handoff procedure.

6, method according to claim 1 also is included in and initiates to receive handoff request from described second communication entity before the described switching.

7, method according to claim 1 also is included in described switching receives the specific data attachment point before from described second communication entity notice.

8, method according to claim 7 also is included in the timestamp in the described notice of specific data attachment point.

9, a kind of method of in communication system, carrying out by communication entity, described communication system comprises another communication entity and user terminal, described method comprises:

From the described reception request message that accesses terminal, described request message is used for data attachment point is switched from described another communication entity;

Notify described switching to described another communication entity; And

Described another communication entity as described data attachment point is replaced.

10, method according to claim 9, also comprise with described communication system in gateway entity communicate to come described another communication entity as described data attachment point is replaced.

11, method according to claim 9 also comprises to described another communication entity sending the notification message that has timestamp on it.

12, a kind of device of operating in communication system comprises:

Be used for setting up the module of data attachment point with first communication entity;

Be used for the module that communicates with the second communication entity;

Be used to provide module to the assessment of one group of predetermined condition of described first communication entity and second communication entity; And

Be used for initiating described data attachment point is switched to from described first communication entity module of described second communication entity based on described assessment.

13, device according to claim 12 also comprises being used for before initiating described switching in the later module that communicates with described second communication entity of preset time.

14, device according to claim 12 also comprises the module that has been used for process time enough since permission was switched from the last time before the described switching of initiation.

15, device according to claim 12 also comprises being used to provide one group of criterion of a described group communication condition and the module of initiating described switching after satisfying described one group of criterion.

16, device according to claim 12 also comprises being used for initiating the module that described handoff procedure sends a request message to described second communication entity.

17, device according to claim 12 also comprises the module that is used for receiving from described second communication entity handoff request before initiating described switching.

18, device according to claim 12 also comprises the module that is used for receiving from described second communication entity the notice of specific data attachment point before described switching.

19, device according to claim 18, wherein, the notice of described specific data attachment point also comprises timestamp.

20, a kind of communication entity of in communication system, operating, described communication system comprises another communication entity and user terminal, described communication entity comprises:

Be used for receiving the module be used for request message that data attachment point is switched from described another communication entity from described accessing terminal;

Be used for notifying the module of described switching to described another communication entity; And

Be used for the module of replacing to as described another communication entity of described data attachment point.

21, communication entity according to claim 20 comprises that also the gateway entity that is used for described communication system communicates next module to replacing as described another communication entity of described data attachment point.

22, communication entity according to claim 21 also comprises the module that is used for sending to described another communication entity the notification message that has timestamp on it.

23, a kind of accessing terminal of operating in communication system comprises:

Processor; And

Circuit, it is coupled to described processor, is used for: set up data attachment point with first communication entity, communicate with the second communication entity, the assessment to one group of predetermined condition of described first communication entity and second communication entity is provided; And, initiate described data attachment point is switched to described second communication entity from described first communication entity based on described assessment.

24, according to claim 23 accessing terminal, wherein, described circuit and described processor also are used for communicating with described second communication entity after preset time before initiating described switching.

25, according to claim 23 accessing terminal, wherein, described circuit and described processor also have been used for since permission was switched from the last time before the described switching of initiation through time enough.

26, according to claim 23 accessing terminal, wherein, described circuit and described processor also are used to one group of criterion of a described group communication condition is provided and initiate described switching after satisfying described one group of criterion.

27, according to claim 23 accessing terminal, wherein, described circuit and described processor also are used for sending a request message to described second communication entity at the described handoff procedure of initiation.

28, according to claim 23 accessing terminal, wherein, described circuit and described processor also are used for receiving handoff request from described second communication entity before initiating described switching.

29, according to claim 23 accessing terminal, wherein, described circuit and described processor also are used for receiving from described second communication entity the notice of specific data attachment point before described switching.

30, according to claim 29 accessing terminal, wherein, the notice of described specific data attachment point also comprises timestamp.

31, a kind of communication entity of in communication system, operating, described communication system comprises another communication entity and user terminal, described communication entity comprises:

Processor; And

Circuit, it is coupled to described processor, be used for: from described access terminal to receive be used for request message that data attachment point is switched from described another communication entity, notify described switching to described another communication entity, and, described another communication entity as described data attachment point is replaced.

32, communication entity according to claim 31, wherein, described processor and described circuit also are used for communicating described another communication entity as described data attachment point is replaced with the gateway entity of described communication system.

33, communication entity according to claim 31, wherein, described processor and described circuit also are used for sending the notification message that has timestamp on it to described another communication entity.

34, a kind of computer product, it has computer-readable medium, and described computer-readable medium comprises computer-readable instruction, is used for:

Set up data attachment point with first communication entity;

Communicate with the second communication entity;

Assessment to one group of predetermined condition of described first communication entity and second communication entity is provided; And

Initiate described data attachment point is switched to described second communication entity from described first communication entity based on described assessment.

35, computer product according to claim 34, wherein, described computer-readable medium also comprises and being used for before initiating described switching at the later computer-readable instruction that communicates with described second communication entity of preset time.

36, computer product according to claim 34, wherein, described computer-readable medium also comprises the computer-readable instruction that has been used for process time enough since permission was switched from the last time before the described switching of initiation.

37, computer product according to claim 34, wherein, described computer-readable medium also comprises and is used to provide one group of criterion of a described group communication condition and the computer-readable instruction of initiating described switching after satisfying described one group of criterion.

38, computer product according to claim 34, wherein, described computer-readable medium also comprises and is used for initiating the computer-readable instruction that described handoff procedure sends a request message to described second communication entity.

39, computer product according to claim 34, wherein, described computer-readable medium also comprises the computer-readable instruction that is used for receiving from described second communication entity handoff request before initiating described switching.

40, computer product according to claim 34, wherein, described computer-readable medium also comprises the computer-readable instruction that is used for receiving from described second communication entity the notice of specific data attachment point before described switching.

41, computer product according to claim 34, the notice of described specific data attachment point also comprises timestamp.

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