CN1992957A

CN1992957A - Wireless access network framework and method for realizing real-time service nondestructive emigration thereof

Info

Publication number: CN1992957A
Application number: CNA2005100034244A
Authority: CN
Inventors: 王宗杰; 许炳; 梁欣刚
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2005-12-30
Filing date: 2005-12-30
Publication date: 2007-07-04
Anticipated expiration: 2025-12-30
Also published as: CN1992957B

Abstract

The invention relates to a wireless access network and relative real-time service non-damage transfer method, wherein said network comprises ERS (edge wireless base station) and IAGW (IP access network gate). And the method comprises that: when UE has region switch, source ERS reports the setting information of wireless interface protocol stack to the IAGW; IAGW via said setting information builds relative wireless interface protocol stack to receive and store the real-time service data of UE; when the UE region switch is completed, IAGW sends the setting information of said wireless interface protocol stack to the target ERS of UE; target ERS via setting information builds relative wireless interface protocol stack to receive the real-time service data from IAGW. The invention can confirm the real-time property of UE switch and realize non-damage transfer between source base station and target base station.

Description

The implementation method of Radio Access Network framework and real-time service nondestructive migration thereof

Technical field

The present invention relates to network communication field, relate in particular to the implementation method of a kind of Radio Access Network framework and real-time service nondestructive thereof migration.

Background technology

UMTS (Universal Mobile Telecommunications System, universal mobile telecommunications system) is a kind of employing WCDMA (Wideband Code Division Multiple Access, Wideband Code Division Multiple Access (WCDMA)) 3-G (Generation Three mobile communication system) of air interface technologies also calls the WCDMA communication system to the UMTS system usually.The UMTS system has adopted and the similar system configuration of second generation mobile communication system, and its system configuration as shown in Figure 1.This system configuration mainly comprises RAN (Radio AccessNetwork, Radio Access Network) and CN (Core Network, core network).Wherein RAN is used to handle all and wireless function associated, and CN handles that all voice calls are connected with data in the UMTS system, and the exchange of realization and external network and routing function.CN from be divided in logic circuit commutative field (Circuit Switched, CS) and PS (Packet Switched, packet-switched domain).UTRAN (UMTS Territorial Radio Access Network, UMTS Terrestrial radio access network), CN have constituted whole UMTS system with subscriber equipment.

The network configuration of UTRAN comprises one or several RNS (RNS) as shown in Figure 2.A RNS is made up of a RNC (Radio Network Controller, radio network controller) and one or more NodeB (base station).Interface between RNC and the CN is the Iu interface, and NodeB is connected by Iub interface with RNC.In UTRAN inside, interconnected by Iur between the RNC, Iur can connect or connect by transmission network by the direct physical between the RNC.RNC is used for distributing and is attached thereto with control or the Radio Resource of relevant NodeB.NodeB then finishes the conversion of the data flow between Iub interface and the Uu interface, also participates in a part of RRM simultaneously.

NodeB is the base station (being radio receiving-transmitting unit) of WCDMA system, comprises radio receiving-transmitting unit and Base-Band Processing parts.By the Iub interface and the RNC interconnection of standard, mainly finish the processing of Uu interface physical layer protocol.Its major function is spread spectrum, modulation, chnnel coding and despreading, demodulation, channel-decoding, also comprises the functions such as mutual conversion of baseband signal and radiofrequency signal.

RNC is used to control the Radio Resource of UTRAN, mainly finishes functions such as connection foundation and disconnection, switching, the merging of grand diversity, RRM control.Specific as follows:

1, executive system information broadcast and system's access control function;

2, mobile management function such as switching and RNC Relocation (migration) or reorientation;

3, RRM and controlled function such as grand diversity merging, power control, radio bearer distribution.

3GPP (Third Generation Partnership Projects, third generation partnership project) considers the competitiveness of future network, considering that at present network is in this how evolution in future, have a variety of evolution schemes to launch discussion at 3GPP, the purpose of network evolution is to be desirable to provide a kind of low time delay, high data rate, high power system capacity and covering, low cost, complete IP-based network.

Existing a kind of network evolution scheme is the two-layer node framework, and the schematic diagram of this framework as shown in Figure 3.Under this framework, ERS (Edge Radio Station, wireless station, border) be the NodeB after the evolution, the function of most RNC before having, and take new physical-layer techniques, as OFDM (orthogonal frequency division multiplexing, OFDM), IAGW (IPAccess GateWay, the IP IAD) has part SGSN (Serving GPRSSupporting Node, service universal grouping wireless business supporting node) function of function and former GGSN (Gateway GPRS Supporting Node, ggsn).

In order to guarantee the smooth evolution of existing UTRAN framework, the two-layer node framework has been reused existing protocol to greatest extent.At the wireless interface oral-lateral, ERS is owing to merged the function of most RNC in the past, except keeping original physical layer function (L1), added MAC (Mdium Access Control again, medium access control layer) layer, RLC (Radio Link Control, Radio Link control) layer, PDCP (Packet Data Convergence Protocol, packet data convergence protocol) layer, RRC (Radio Resources Control, radio resource control) layer wait the function of protocol layer.Between ERS and IAGW, adopt GTP-U (GPRS Tunneling Protocol for User Plane, GPRS Tunnel Protocol user plane) tunnel transmission agreement.Two-layer node framework after the evolution because moving down of Radio interface protocols stack or user face protocol stack reduced transmission node, makes call setup time-delay and transmission delay shorten, and has improved data transmission performance.

Under above-mentioned two-layer node framework, because being displaced downwardly to ERS, handles in the air protocol stack, and when the switching flow between generation ERS, source ERS must be forwarded to the UE context of preserving in it among target ERS through IAGW, and whole migration flow process is as shown in Figure 4.In flow process shown in Figure 4, SERS is source ERS, and TERS is target ERS.Comprise the steps:

1, SERS needs to switch to TERS according to collected measurement data judgement UE.Because in evolution architecture, no Iur interface can't exchange data between SERS and TERS.So SERS adjudicates in direct-cut operation, the Iu interface need carry out reorientation, sends RELOCATION REQUIRED (needing reorientation) message to IAGW, triggers the Relocation process.

2, after IAGW receives above-mentioned RELOCATION REQUIRED message, send RELOCATION REQUEST (re-positioning request) message to TERS, request TERS is the required resource of UE preassignment.

3, after TERS receives RELOCATION REQUEST message, start relevant resource allocator, set up RRC connection, RAB (Radio Access Bearer RAB) carrying.Concrete processing procedure is: set up the PDCP/RLC/MAC entity, set up new Radio Link, and start transmission and reception on the new Radio Link; Start simultaneously and set up GTP-U Tunnels for PSRABs (setting up the GTP_U tunnel of PS territory RAB) transmission bearer, set up the user plane bearer between TERS and the IAGW.After all essential resources are successfully set up, distributed, target ERS will send RELOCATION REQUEST ACKNOWEDGE (re-positioning request affirmation) message to IAGW, confirm the resource allocation success.

4, after IAGW received RELOCATION REQUEST ACKNOWEDGE message, the resource allocation of judgement goal systems was ready, and decision continues the reorientation flow process.IAGW will send RELOCATION COMMAND (reorientation order) message to source ERS, the execution of notification source ERS trigger re-positioning this moment.

5, after source ERS receives RELOCATION COMMAND message, stop the reorientation set-up procedure, and read the switching-related parameters of RELOCATION COMMAND message, prepare PHYSICAL CHANNEL RECONFIGURATION (physical channel reconfigures) message of direct-cut operation, by the Uu interface this PHYSICAL CHANNEL RECONFIGURATION message is sent to UE, triggers UE and insert Target cell.

6, after UE receives PHYSICAL CHANNEL RECONFIGURATION message, will insert Target cell according to the information that PHYSICAL CHANNEL RECONFIGURATION message provides.After successfully inserting Target cell, UE will send PHYSICAL CHANNELRECONFIGURATION COMPLETE (physical channel reconfigures and finishes) message and give TERS, and notice TERS handover success triggers the execution of TERS reorientation.

7, after TERS receives PHYSICAL CHANNEL RECONFIGURATIONCOMPLETE message, begin to carry out the SERS function; And send RELOCATION DETECT (reorientation detection) message to IAGW, point out to detect SRNS (Serving Radio NetworkSubsystem, SRNS Serving Radio Network Subsystem) and carry out reorientation.After IAGW receives this message, user's face is switched to TERS by SERS.

8, TERS sends RELOCATION COMPLETE (reorientation is finished) message to IAGW, and notice IAGW target ERS has finished the RELOCATION process.IAGW receives RELOCATION COMPLETE message, carries out Iu release order, and the Iu interface that is discharged into SERS connects.Under real-time condition, source ERS will abandon the Frame of its preservation,

The shortcoming of above-mentioned migration flow process is: whole migration flow process more complicated.In order to guarantee the time-delay of handoff procedure, in the process that realizes migration, the data among the ERS of source, such as, the UE contextual information of its preservation can't be transferred to target ERS from source ERS like that according to the lossless migration flow process, thereby cause lot of data to lose.

Summary of the invention

In view of above-mentioned existing in prior technology problem, the implementation method that the purpose of this invention is to provide the migration of a kind of Radio Access Network framework and real-time service nondestructive thereof, thereby can when guaranteeing UE handoff procedure real-time, realize real time business data lossless migration between source base station and purpose base station of UE.

The objective of the invention is to be achieved through the following technical solutions:

A kind of Radio Access Network framework, comprise wireless base station, border ERS and IP IAD IAGW, air protocol stack among the ERS comprises the medium access control layer E-MAC of expansion and the wireless chain control layer E-RLC of expansion, E-MAC has also added cutting apart/cascade function of rlc layer except having the MAC layer function;

IAGW has comprised the Radio interface protocols stack of E-RLC and the Radio interface protocols stack of radio resource control rrc layer, the Radio interface protocols stack of described E-RLC and the Radio interface protocols stack of rrc layer activate the back by source ERS and use when user equipment (UE) switches, adopt GPRS Tunnel Protocol user plane GTP-U tunnel or mobile IP host-host protocol carrying high-level signaling and data between ERS and IAGW.

Described E-RLC comprises:

Cache module: the real time business for adopting unacknowledged mode UM and telecommunication management pattern TM carrying provides the buffer memory ability;

Automatic repeat request module:, provide the execution buffering of rlc layer and the automatic repeat request ARQ function of retransmission mechanism for adopting answer-mode AM data carried by data business;

Sequence number maintenance module: by RLC Service Data Unit SDU sequence number being safeguarded the maintenance function of the PDCP sequence number that packet data convergence protocol PDCP layer is provided.

Real time business data migration method in a kind of Radio Access Network comprises step:

A, the sub-district takes place when switching as UE, source ERS will be uploaded to IAGW at the configuration information of the Radio interface protocols stack of this UE, IAGW sets up corresponding Radio interface protocols stack example according to this configuration information, by this example, receives and preserve the real time business data of UE;

B, when described UE sub-district switch finish after, IAGW will be handed down to the target ERS of UE at the configuration information of the Radio interface protocols stack of this UE, target ERS sets up corresponding Radio interface protocols stack example according to this configuration information, by this example, receives the described real time business data that IAGW issues.

Described steps A specifically comprises:

A1, the sub-district takes place when switching as described UE, source ERS sends the context migration request Context TransferRequest message that comprises at the configuration information of the Radio interface protocols stack E-RLC layer of this UE and rrc layer example to IAGW;

A2, IAGW are according to the described Context Transfer Request message that receives, set up corresponding Radio interface protocols stack E-RLC layer and rrc layer example, send context migration response Context Transfer Response message to source ERS at described UE;

After A3, source ERS receive described Context Transfer Response message, at control plane, the RRC message of this UE is passed through IAGW, at user plane, with the real time business data that issue be buffered in the E-RLC layer that its inner E-RLC frame passes to IAGW and carry out buffer memory.

Described steps A 3 also comprises:

After source ERS receives described Context Transfer Response message, stop of the work of its internal needle to the Radio interface protocols stack example of described UE, at user plane, when continuing to issue the real time business data, stop its inner E-RLC layer protocol stack caching function.

Described steps A also comprises:

A4, after the described Radio interface protocols stack example that IAGW sets up is started working, IAGW notification target ERS is that described UE sets up Radio Link and Iu+ transmission bearer, IAGW also notifies described UE to carry out the air protocol stack by source ERS and reshuffles, switch to the sub-district that target ERS is covered;

A5, UE reshuffle after its air protocol stack finishes, and send handoff completion message to IAGW, comprise the frame number of the descending E-RLC frame that the UE expectation receives in this handoff completion message, after IAGW receives this message, delete the E-RLC frame that has issued in its buffer area.

Described step B specifically comprises:

B1, when described UE sub-district switch finish after, IAGW sends Context TransferRequest message to target ERS, comprises among the IAGW configuration information at the Radio interface protocols stack of described UE in the described Context Transfer Request message;

After B2, target ERS receive described Context Transfer Request message, set up corresponding Radio interface protocols stack example, send Context Transfer Response message to IAGW at described UE;

B3, IAGW send the E-RLC frame that comprises the real time business data that is buffered in its inside to target ERS after receiving described Context Transfer Response message.

Described step B3 also comprises:

After IAGW will be buffered in its inner E-RLC frame and send target ERS to, delete the Radio interface protocols stack example of its internal needle, behind the E-RLC frame in emptying its buffer area, cancel this buffer area described UE.

Described step B also comprises:

After the switching of described UE sub-district is finished, IAGW starts the E-RLC buffer data and uploads timer in this locality, after the timing of the timing length of this timer arrives, IAGW notification source ERS deletion is at the Radio Link of described UE, be released to the transmission bearer resource that described UE distributes, after the Radio Link deletion of described UE, ERS deletion in source is at the contextual information of this UE.

Described step B also comprises:

When the UE that initiate to switch is in high-speed motion or when cell edge is roamed back and forth, after handoff procedure is finished, IAGW will not be handed down to the target ERS of described UE at the configuration information of the Radio interface protocols stack of described UE.

Described Context Transfer Request message and Context Transfer Response message realize by the RNS application protocol RANAP of revising the Iu interface.

Described step B also comprises:

After the folding process of described air protocol stack function is finished, accepting target ERS that air protocol stack function moves down is responsible for realizing at the management of the Radio Link of described UE and the buffer memory and the transmitting function of radio frames, UE is under the control of this target ERS, communicates and handoff procedure according to normal agreement flow process.

As seen from the above technical solution provided by the invention, the present invention is by redesigning the ERS of existing two-layer node network architecture and the function of IAGW, adopt the mode of moving and moving down on the air protocol stack to replace the contextual transfer of UE, simplified the migration flow process of the real time business data of UE.Can under the prerequisite of not interrupting the data transmission, finish the reconstruction of downlink data buffer memory at switching anchor point place, when guaranteeing the handoff procedure real-time, guarantee the real time business data lossless migration in the handoff procedure.

Description of drawings

Fig. 1 is the structural representation of UMTS system;

Fig. 2 is the schematic network structure of UTRAN;

Fig. 3 is the schematic diagram of existing wireless access network network two-layer node framework;

Fig. 4 is for following the flow chart of transition process in the existing wireless access network network two-layer node framework;

Fig. 5 is the user face protocol stack schematic diagram of Radio Access Network framework of the present invention in the normal transmission process;

Fig. 6 is the user face protocol stack schematic diagram of Radio Access Network framework of the present invention under switching state;

Fig. 7 is the process chart of the specific implementation of the method for the invention;

Fig. 8 is for moving past the flow chart of journey on the protocol stack function of eating dishes without rice or wine in the method for the invention;

Fig. 9 flows to schematic diagram for the user data that UE switches after finishing;

Figure 10 is the flow chart of the protocol stack function folding process of eating dishes without rice or wine in the method for the invention.

Embodiment

The invention provides the implementation method of a kind of Radio Access Network framework and real-time service nondestructive thereof migration, core of the present invention is: adopt the mode of moving and moving down on the air protocol stack to replace the contextual transfer of UE, simplified the migration flow process.

The Radio Access Network framework that the present invention proposes is a kind of new two-layer node network architecture.This framework designs again to the ERS of existing two-layer node network architecture and the function of IAGW.Specific as follows:

Air protocol stack among the ERS is evolved into E-MAC (MAC of expansion)/E-RLC (RLC of expansion) by original MAC/RLC/PDCP, and wherein E-MAC has added also that rlc layer is original to be cut apart/cascade function except that keeping original MAC layer function.For the data service of adopting AM (answer-mode) mode carrying.E-RLC has inherited ARQ (automatic repeat request) function of original execution buffering of rlc layer and retransmission mechanism, to guarantee the sequence delivery of data.

Described E-RLC comprises:

Cache module: the real time business for adopting unacknowledged mode UM and telecommunication management pattern TM carrying, the buffer memory ability is provided, in data transmission procedure, provide the flow-control mechanism between E-RLC protocol layer and E-MAC protocol layer.

Automatic repeat request module: for adopting answer-mode AM data carried by data business, provide the execution buffering of rlc layer and the automatic repeat request ARQ function of retransmission mechanism, to guarantee the sequence delivery of data.

IAGW has also comprised the radio protocol stack of E-RLC layer, rrc layer except realize original core net node function.But the Radio interface protocols stack among the IAGW only uses in some cases, is activated by source ERS during as switching, does not use generally speaking.Between ERS and IAGW, can adopt multiple transport protocols carrying high-level signaling and data such as GTP-U tunnel, mobile IP.

Fig. 5 is the user face protocol stack schematic diagram of Radio Access Network framework of the present invention in the normal transmission process, and Fig. 6 is the user face protocol stack schematic diagram of Radio Access Network framework of the present invention under switching state.

Based on above-mentioned Radio Access Network framework, the invention provides a kind of moving method of real time business data, the handling process of the specific implementation of this method comprises the steps: as shown in Figure 7

Step 7-1, source ERS carry out moving on the air protocol stack function.

In the Radio Access Network framework that the invention described above proposes, can be for the source ERS of UE service periodically to UE transmission measuring control information, request UE reports the measurement result of wireless propagation environment.When UE was in the edge of certain sub-district, source ERS will make switch decision according to the measurement report that UE reports, and this switch decision will trigger the generation of UE handoff procedure, and simultaneously, UE will carry out the transition process of real time business data.

When the transition process of real time business begins, at first carry out moving past journey on the air protocol stack function, the flow process that moves past journey on this air protocol stack function as shown in Figure 8.Specifically describe as follows:

Source ERS at first gives IAGW by sending a Context Transfer Request (context migration request) message with the IAGW interface, and request IAGW is the corresponding high-rise example of UE activation Radio interface protocols stack.Mainly comprise in this message among the present source ERS at the Radio interface protocols stack example E-RLC layer of this UE and the configuration information of rrc layer, after IAGW receives this message, can set up corresponding Radio interface protocols stack E-RLC layer and RRC example, after this example is started working, the E-RLC frame that beginning buffer memory when continuing to issue data is received, send Context Transfer Response (context migration response) message simultaneously and give source ERS, after source ERS receives this message, can stop the work of own inner Radio interface protocols stack example of being correlated with.At control plane, source ERS stops the RRC message of corresponding UE is handled, and only carries out the transparent transmission function between UE and IAGW.At user plane, source ERS is when continuing to issue the real time business data, stop own inner E-RLC layer protocol stack caching function, and these real time business data and E-RLC frame of being buffered in it are sent to IAGW by the interface between ERS and IAGW, the E-RLC layer of transferring to IAGW carries out buffer memory.

Step 7-2, target ERS are that UE sets up new Radio Link.

After the Radio interface protocols stack example of setting up for corresponding UE among the above-mentioned IAGW is started working, IAGW will by and the Iu+ interface of target ERS, notification target ERS is that UE sets up Radio Link and Iu+ transmission bearer, carry out the air protocol stack by source ERS notice UE simultaneously and reshuffle, switch to the sub-district that target ERS is covered.UE reshuffles after its air protocol stack finishes, and sends handoff completion message to IAGW, indicates its handoff procedure to finish.Contain the frame number of the descending E-RLC frame of UE expectation reception in the described handoff completion message, after IAGW receives this message, delete the E-RLC frame that has issued within it in the buffer area.Transfer of data after switching is finished is from first E-RLC frame that is not sent out.This first the E-RLC frame that is not sent out is the descending E-RLC frame that the UE expectation receives.

The user data that above-mentioned UE switches after finishing flows to schematic diagram as shown in Figure 9.

The old Radio Link of step 7-3, source ERS deletion UE.

After described UE handoff procedure is finished, IAGW starts the E-RLC buffer data and uploads timer in this locality, after the timing of the timing length of this timer arrives, IAGW can by and source ERS between the Iu+ interface, notification source ERS deletes the former Radio Link of described UE, is released to the transmission bearer resource that this UE distributes.After the former Radio Link deletion of UE, source ERS can delete the contextual information at this UE.

Step 7-4, IAGW carry out air protocol stack function and move down.

Because E-RLC air protocol layer is positioned at IAGW and can introduces certain data transmission problems, as on the back haul link between ERS and IAGW, producing a large amount of Flow Control frames.Therefore, after the transition process of UE was finished, IAGW can trigger the process that air protocol stack function moves down.The flow process of this air protocol stack function folding process as shown in figure 10.Specifically describe as follows:

In the folding process of air protocol stack function, IAGW can send Context Transfer Request message to target ERS by the Iu+ interface, and request target ERS is Radio interface protocols stack high-rise example, i.e. E-RLC and the rrc layer example that UE sets up a correspondence.Comprise Radio interface protocols stack configuration information relevant among the present IAGW in the described Context Transfer Request message.After target ERS receives this message, can set up relevant Radio interface protocols stack example, and send Context TransferResponse message to IAGW, after IAGW receives this message, with the E-RLC frame that comprises the real time business data that is buffered in its inside by and target ERS between the Iu+ interface be sent to target ERS, then, delete the Radio interface protocols stack example of own internal needle to this UE, and after emptying the interior E-RLC frame of its buffer area, cancel this buffer area.

After function folding process of air protocol stack and handoff procedure finish, accepting target ERS that air protocol stack function moves down is responsible for realizing at the management of the Radio Link of described UE and the buffer memory and the transmitting function of radio frames, UE is in this target ERS control down, communicates and handoff procedure according to normal agreement flow process.

In above-mentioned real time business transition process, if the UE that initiates to switch is in high-speed motion or roams back and forth at cell edge.If after handoff procedure is finished, IAGW is displaced downwardly to target ERS with air protocol stack example, will cause UE frequently to initiate to move flow process.For fear of in described two-layer node framework, wasting, can consider also that in such cases the air protocol stack function of not initiating described step 7-4 moves down flow process because of UE moves the interface-free resources that causes continually.And,, will carry out above-mentioned real time business transition process continuously because its switching frequency is lower for the UE that moves at low speed.

Context Transfer Request/Response message in the above-mentioned real time business transition process can realize by revising existing Iu interface RANAP (RNS Application Protocol, RNS application protocol) agreement.

In a word, switching flow in the two-layer node framework after the described improvement of the invention described above and real time business transition process are simpler than existing switching flow and real time business transition process, and can deal with more exception.

The above; only for the preferable embodiment of the present invention, but protection scope of the present invention is not limited thereto, and anyly is familiar with those skilled in the art in the technical scope that the present invention discloses; the variation that can expect easily or replacement all should be encompassed within protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection range of claim.

Claims

1, a kind of Radio Access Network framework comprises wireless base station, border ERS and IP IAD IAGW, it is characterized in that:

Air protocol stack among the ERS comprises the medium access control layer E-MAC of expansion and the wireless chain control layer E-RLC of expansion, and E-MAC has also added cutting apart/cascade function of rlc layer except having the MAC layer function;

2, Radio Access Network framework according to claim 1 is characterized in that, described E-RLC comprises:

3, real time business data migration method in a kind of Radio Access Network is characterized in that, comprises step:

4, method according to claim 3 is characterized in that, described steps A specifically comprises:

5, method according to claim 4 is characterized in that, described steps A 3 also comprises:

6, method according to claim 4 is characterized in that, described steps A also comprises:

7, according to claim 3,4,5 or 6 described methods, it is characterized in that described step B specifically comprises:

8, method according to claim 7 is characterized in that, described step B3 also comprises:

9, method according to claim 7 is characterized in that, described step B also comprises:

10, method according to claim 7 is characterized in that, described step B also comprises:

11, method according to claim 7 is characterized in that, described Context TransferRequest message and Context Transfer Response message realize by the RNS application protocol RANAP of revising the Iu interface.

12, method according to claim 7 is characterized in that, described step B also comprises: