CN100461960C

CN100461960C - Method for realizing active state inter-AN switching in network

Info

Publication number: CN100461960C
Application number: CNB2006100568458A
Authority: CN
Inventors: 高全中
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2005-07-18
Filing date: 2006-03-07
Publication date: 2009-02-11
Anticipated expiration: 2026-03-07
Also published as: CN1933661A

Abstract

A method for realizing switch-over between multiple active state AN in network includes confirming that switch-over operation is required to be carried out between multiple active state access network AN and starting up switching-over course, setting up connection of destination packet control function PCF side to packet data service network PDSN then sending data message carried with double cast indicating information simultaneously to both source PCF side and destination PCF side by PDSN and buffer-storing received data separately by both sides.

Description

Method for realizing active state inter-AN switching in network

Technical Field

The present invention relates to the field of network communication technologies, and in particular, to a method for implementing active inter-AN handover in a network.

Background

With the development of communication technology, in order to solve the bottleneck problem on the air interface in the CDMA system, 3GPP2 (international organization for standardization of third generation mobile communication) issued a standard of HRPD (HRPD-high rate Packet Data) network technology. The main purpose is to increase the data transmission rate of the radio interface, which can provide forward data rates up to 2.4Mbit/s compared to 153.6kbit/s for cdma20001 x.

In the HRPD network, new modulation technology is adopted on the air interface by the HRPD network, and methods such as data rate control, scheduling optimization, time division multiplexing and the like are added, so that the data transmission rate on the air interface is greatly improved. The HRPD technology can adopt a special data channel to support high-speed packet data service on a CDMA carrier frequency (1.25MHz), the forward highest data rate can reach 2.4576Mbit/s, and the reverse direction supports the peak data rate of a single user of 153.6 kbit/s.

When HRPD network deployment is carried out, an independent carrier frequency is required to support HRPD. This makes it possible for a user terminal to move from one AN to another AN in the HRPD network when the user terminal moves in the HRPD network, and at this time, a handover process from the source AN to the target AN is required.

Currently, in the 3GPP2 standard, handover in Dormant state between ANs (access networks) is only supported, and the corresponding handover process specifically includes: when a terminal develops data service in AN HRPD (high rate packet data) network and moves to a cell coverage edge zone, the terminal needs to be switched to another AN to continue to develop the data service, and at the moment, the system switches the packet data service from AN activated state to a Dormant state in a source AN and then switches the packet data service to a target AN in the Dormant state; after entering the target AN, the system switches the packet data service from the Dormant state to the active state again at the target AN.

The above-mentioned handoff method between ANs can realize the handoff operation from the source AN to the target AN. However, for data services with high real-time requirements, such as VoIP (voice over IP), Video Phone, PTT (push to talk), streaming media, etc., if the above switching process is adopted, service interruption is likely to occur, which seriously affects the use of the service by the user.

That is, in the current standard method for implementing dormant handoff between AN and PCF, in the handoff process, the PPP (point-to-point protocol) connection in use needs to be released, and the PDSN needs to allocate a new PPP connection to the destination network. In the process of reallocating the PPP connection, on one hand, the newly-allocated PPP connection may cause failure in the allocation process due to reasons such as resource problems, so that the user service is interrupted; on the other hand, the PDSN needs a certain time to reestablish a PPP connection, and therefore, a relatively large delay effect is also caused to the current service of the user.

For this reason, it is necessary to provide a hard handoff process that can ensure uninterrupted service during handoff between ANs. However, in the current standard, only the above-mentioned dormant inter-AN handoff processing procedure is implemented, and the active hard handoff procedure between the HRPD system AN and the PCF is not defined.

Disclosure of Invention

In view of the above problems in the prior art, AN object of the present invention is to provide a method for implementing AN active inter-AN handover in a network, so as to effectively improve reliability of data transmission during the handover.

The purpose of the invention is realized by the following technical scheme:

the invention provides a method for realizing active state inter-AN switching in a network, which comprises the following steps:

A. determining that switching operation is required between access networks AN in AN activated state, and starting a switching process;

B. in the switching process, establishing the connection between a target packet control function PCF side and a packet data service network PDSN;

C. the PDSN sends data messages carrying the double-broadcasting indication information to a source PCF side and a target PCF side at the same time, and the two sides respectively cache the received data carrying the double-broadcasting indication information; if the connection is established between the terminal and the target AN, the target AN sends the time delay sensitive service which is not overtime and all the non-time delay sensitive service data to the terminal, otherwise, the source AN sends the cached effective data to the terminal.

In the present invention, when switching between ANs belonging to different PCFs, said step B comprises:

after receiving the switching request message from the source AN, the target AN sends a connection establishing request to the target PCF, establishes the connection between the target AN and the target PCF, and meanwhile, the target PCF also needs to register to the packet data service network PDSN to establish the connection between the PCF and the PDSN.

The step C further comprises the following steps:

c1, the source AN sends channel assignment message to the terminal according to the switching response message sent by the target AN.

In the present invention, before executing step C1, the method further includes:

c0, the source AN determines the time for sending the channel assignment message to the terminal according to the channel condition and the service attribute of the terminal, and performs the step C1 at the determined time.

The step C0 includes:

if the delay sensitive service exists in the service developed by the terminal and the allowed delay is not exceeded, immediately executing step C1; if the service developed by the terminal does not have the delay sensitive service and the channel quality always meets the preset conditions, the source AN executes the step C1 after sending the cached data which does not carry the double-broadcasting indication information; if the channel quality does not meet the predetermined condition, step C1 is directly performed.

The step that the target AN sends the time delay sensitive service which is not overtime and all the non-time delay sensitive service data to the terminal comprises the following steps:

when the connection is established between the terminal and the target AN and the source AN finishes sending the cached reverse data, the connection between the source AN and the PDSN is released; meanwhile, after receiving the channel establishment completion message sent by the terminal, the target AN resets the RLP information and immediately starts to send the non-overtime delay-sensitive service data packets and all the non-delay-sensitive service data packets to the terminal.

The method of the invention also comprises the following steps:

the PDSN receives reverse data sent by the source AN and the target AN, and sends the reverse data after sequencing according to the self-caching condition and the service type, wherein the sequencing specifically comprises the following steps: for the delay sensitive service, the service packets from the source AN and the target AN are sequenced before overtime, and for the non-delay sensitive service, the reverse data sent by the source AN is sent firstly in the range allowed by the buffer area, and the reverse data sent by the target AN is sent later.

The time point when the PDSN starts to send the reverse data from the target AN is as follows:

the non-delay sensitive service data of the source AN is completely sent, and the connection between the source PCF and the PDSN is released at a time point;

or,

the data of the source AN is delay sensitive service, if the data packet is overtime, the data from the target AN is sent, and meanwhile, the connection between the source AN and the PCF and the PDSN is released;

or,

when the time delay sensitive service data from the target AN is about to time out, the data from the target AN is sent, and meanwhile, the connection between the target AN and the source PCF and the PDSN is released.

The step of sending the cached effective data to the terminal by the source AN further comprises the following steps:

when the timer is overtime, the target AN still does not receive the channel establishment response message from the terminal, the terminal is considered to fail to switch the channel, and the target AN sends a switching failure message to the source AN and releases the connection between the target PCF and the PDSN; when the source AN receives the message of switching failure, the source AN reestablishes the connection with the terminal and sends the cached forward valid data to the terminal;

or,

and when the source AN detects that the terminal recovers the channel parameters of the source AN, the source AN sends the cached effective data to the terminal.

The method of the invention also comprises the following steps:

when the PDSN releases a connection with the PCF, the PDSN will only send data to the PCF that has not released the connection, and will not carry the bi-cast indication information in the sent data.

The method further comprises the following steps:

D. and establishing a communication interface between the source AN and the target AN, and processing data between the source AN and the target AN based on the communication interface in the switching process.

The step D comprises the following steps:

d1, determining a data switching reference point between the source AN and the target AN;

d2, processing data between the source AN and the target AN based on the switching datum point and the established communication interface.

The step D1 includes:

after the source AN finishes sending the forward data, the last reset radio link protocol RLP serial number sent by the source AN is used as a forward data switching reference point to be sent to the target AN;

after receiving the switching start message, the source AN immediately sends a channel assignment TCA message to the user terminal, and determines a switching reference point for reverse data processing with the target AN.

The step D2 includes:

d21, carrying out retransmission processing on the forward data before the switching reference point by the source AN, and informing the target AN to carry out retransmission processing on the forward data after the switching reference point after the source AN sends the corresponding forward data;

or,

d22, the last data sent to the source AN is identified by the PDSN indicating that it is no longer sending forward data to the source AN.

The step D21 further includes:

when the data cached by the target AN reaches a preset value or the terminal is judged to no longer need the retransmission processing of the source AN, the source AN is informed to empty the cached data.

The step D2 includes:

the reverse data before the switching reference point is sent to the PDSN by the source AN, and after the source AN sends all the reverse data to the PDSN, the target AN is instructed to send the reverse data after the switching reference point to the PDSN;

or,

reverse data is simultaneously transmitted by the source AN and the target AN, and is sequenced by the PDSN in AN order in which the reverse data received from the source AN precedes the reverse data received from the target AN.

The step D also comprises the following steps:

when the target AN determines that the switching reference point of the reverse data is smaller than the RLP sequence number of the RLP data expected to be received by the target AN, the source AN actively transfers the received reverse data to the target AN for processing after processing the data before the switching reference point is completed, or the target AN requests the user terminal to retransmit the data between the switching reference point and the sequence number of the RLP data expected to be received by the target AN.

The step D also comprises the following steps:

if the source AN does not transfer the received reverse data to the target AN for processing after processing the data before the switching reference point, the corresponding data will be discarded.

The step D also comprises the following steps:

for multiple RLP instances, data processing between the source AN and the target AN of the RLP instance is performed via one or more signaling.

The service switched between the source AN and the target AN comprises:

real-time traffic and/or non-real-time traffic.

It can be seen from the above technical solutions that the implementation of the present invention enables the source PCF and the destination PCF to perform the caching processing of the data packet according to the corresponding bi-cast indication information, thereby improving the reliability of data transmission in the switching process.

Meanwhile, as the double-broadcasting indication information is transmitted along with the message, the source PCF and the target PCF can be ensured to effectively identify the data needing to be cached, and the caching processing is only carried out on the corresponding data; in this way, not only the network resource occupied by the dual-cast indication message sent separately can be avoided, but also the data loss caused by the dual-cast indication message not arriving in time at the PCF can be avoided, for example, the situation that the data that should be cached at the destination PCF is not cached due to the dual-cast indication message not arriving in time at the destination PCF is inevitably caused.

Drawings

FIG. 1 is a schematic diagram of a normal handover process according to the present invention;

FIG. 2 is a schematic diagram illustrating a process of data processing between the source AN and the target AN in FIG. 1;

fig. 3 is a schematic diagram of a processing procedure when handover fails according to the present invention.

Detailed Description

The invention mainly aims to ensure the reliability of data transmission in the process of active inter-AN switching in AN HRPD network. In the following, a description will be first given of several main technical points involved in the present invention, so as to better understand the whole handover process.

In the present invention, when the a10 connection between the PDSN and the destination PCF is successfully established, the PDSN sends data to the source PCF and the destination PCF at the same time, it should be noted that in the present invention, a bi-cast indication message is also added in the header of the data packet sent to indicate that the data has been sent to the source AN and the destination AN at the same time, the source PCF/AN receives the part of data and then does not continue sending to the terminal, but just buffers it, and at the same time, in order to simplify the processing of the PDSN, the same processing mode is also adopted in the destination PCF/AN.

In the invention, after receiving data carrying Bi-casting (double-casting indication) from PCF, source AN caches the data and decides when to send TCA (channel assignment) message according to channel condition and service attribute of terminal, and channel parameter information carried in TCA message is transmitted by target AN. If delay sensitive service exists in the service developed by the AT (terminal), a TCA message is immediately sent to the terminal. And if only the non-delay sensitive service exists and the channel condition is better, sending the TCA message after sending the cached data (non-retransmission data) which does not carry the Bi-casting information. For the buffered reverse data, the source AN continues to send to the PCF and PDSN.

In the present invention, a processing procedure of Inter-AN (interconnected AN)/Inter-PCF (interconnected PCF) hard handoff, that is, a processing procedure of active state AN hard handoff is shown in fig. 1, and specifically includes the following steps:

step 11: a terminal AT sends a Route Update message to a source AN, wherein the Route Update message comprises neighbor cell information with high signal intensity;

step 12: the source AN determines that hard switching is needed according to the routing update message, determines a corresponding target AN, and then sends a switching Request A13-handoff Request message to the target AN, wherein the message comprises session information and target cell information related to AT;

step 13: after receiving the switching request message, the target AN verifies the message; if the verification is passed, allocating resources, specifically including channel resources and processing resources, and then returning a corresponding response A13-handoff Request Ack message to the source AN;

step 14: the source AN locks the session configuration of the AT, namely, the update processing of the session configuration information is not carried out any more, so as to avoid that the updated session configuration in the switching process can not be known by the target AN;

step 15: after the locking session is configured, the source AN sends a switching command A13-handoff command message to the target AN, wherein the switching command message comprises parameters such as the address of the PDSN, the port number and the like;

step 16: the target AN responds to the A13-handoff command message after receiving the switching command and returns the channel assignment parameters to the source AN;

and step 17: after receiving the channel assignment switching parameter, the source AN sends a switching Start A13-handoff Start message to the target AN to indicate that the switching is started; (ii) a

Step 18: after receiving the switching start message, the target AN establishes A8 connection with the target PCF;

the message for establishing A8 can be added with AN indication that switching between ANs is required and data is required to be issued;

step 19: after receiving the message of establishing A9-Setup-A8 by the connection of A9-A8, the PCF initiates the establishment of A10 connection to the PDSN, namely, sends A11-Registration Request to the PDSN;

step 110: after the connection of A10 is established, the PDSN responds to A11 Registration Reply A11-Registration Reply message to the destination PCF;

step 111: the target PCF completes the A10 connection, completes the A8 establishment and feeds back AN A9-Connect-A8(A9-A8 communication) message to the target AN, and the target AN stops the timer TA 8-Setup;

step 112: after the PDSN judges that the a10 connection is established due to the handoff (i.e., the second a10 connection), the PDSN sends data to the target PCF and the source PCF at the same time, and adds B-signaling Indication information in the GRE (generic routing encapsulation) header of the data packet sent at the same time to indicate that the data has started to be sent to the target PCF and the source PCF at the same time;

the target PCF receives the data and then forwards the data to the target AN, and the source PCF receives the data and then forwards the data to the source AN;

step 113: the source AN receives the data carrying Bi-casting indication from the PCF, then buffers the part of data, and decides when to send TCA message according to the channel condition and service attribute of the terminal, the corresponding parameter is transmitted by the target AN;

the method specifically comprises the following steps: if the service is a delay sensitive service, a TCA message is sent to the terminal immediately, if the service is a non-delay sensitive service and the channel condition is better, the TCA message is sent after the cached data (non-retransmission data) which does not carry the Bi-casting indication is sent, and if the delay service, the non-delay sensitive service and the non-delay sensitive service exist at the same time, the TCA message is sent immediately;

for the cached reverse data, the source AN continues to send to the PCF and the PDSN;

step 114: and after receiving the TCA message, the terminal judges that the cell is the cell of the target AN, and returns a channel establishment completion message to the target AN. Target AN resets RLP after receiving channel completion message, then immediately starts to send forward data packet whose time delay does not exceed the requirement, i.e. sends non-overtime time delay sensitive service data packet and all non-time delay sensitive service data packets to terminal, in short, in this step, only sends cached effective data to terminal;

meanwhile, the reverse data is received and then sent to PCF and PDSN;

step 115: target AN sends UATI (management access terminal identification) assignment message to terminal;

step 116: the AT responds to the UATI assignment acknowledgement message to the target AN, and then the target AN and the AT switch the UATI AT the same time.

Step 117: the target AN sends a session configuration unlocking and fixing message to the terminal;

step 118: AT responds configuration unlocking response message to target AN;

step 119: the target AN sends AN A13 session release request to the source AN, indicating that the handoff has been completed;

step 120: the source AN responds to the target AN with AN A13 session release request response message;

step 121: the target AN sends a UATI releasing request to the source AN, and the UATI is released;

step 122: AT responds to the target AN to send UATI release request response message;

step 123: after the reverse data in the buffer is sent to the PCF/PDSN, the source AN sends AN A9-Release-A8 (Release A9-A8 connection) message, starts a timer TArel9 and releases AN A8 link;

the reverse data information from the source AN/PCF and the target AN/PCF can be received on the PDSN, and the PDSN carries out sequencing processing and then sends the data according to the self-caching condition and the service type, wherein the sequencing processing specifically comprises the following steps: for the time delay sensitive service, the service packets from the source AN/PCF and the target AN/PCF are sequenced before overtime, and for the non-time delay sensitive service, the reverse data sent by the source AN is sent firstly in the range allowed by the buffer area, and the reverse data sent by the target AN/PCF is sent later.

The time points to start sending reverse data from the target AN/PCF may be:

the non-delay-sensitive service data of the source AN/PCF is completely sent, and the A10 connection between the source AN/PCF and the PDSN is released;

the data of the source AN/PCF is delay sensitive service, if a data packet is overtime, the data from the target AN/PCF is sent, and the delay sensitive data from the source AN is not sent any more and is discarded completely. Simultaneously initiating the release of the a10 connection between the originating PCF and the PDSN;

when the time-sensitive service data from the target AN is about to time out, the data from the target AN/PCF is sent, and the time-sensitive data from the source AN/PCF is not sent any more and is discarded completely. At the same time, the release of the a10 connection between the originating PCF and the PDSN is initiated.

Step 124: after receiving the A9-Release-A8 message of the original AN, the source PCF sends AN A11-Registration Request (A11 Registration Request) message to the PDSN, and releases the A10 connection;

step 125: after releasing the a10 connection, the PDSN no longer sends data to the source AN/PCF, and meanwhile, the later sent data no longer carries the Bi-casting indication in the GRE header. Simultaneously, returning an A11-Registration Reply message to the source PCF, and releasing Al0 connection resources by the source PCF;

step 126: the source PCF releases the A8 connection and responds to the A9-Release-A8 Complete message to the source AN; the source AN stops the timer TArel 9.

In the above switching process, in order to implement the data processing between the source AN and the target AN, the invention also provides a hard switching processing method when adding the service interface, a corresponding service interface is established between the source AN and the target AN, and the hard switching between the source AN and the target AN can be implemented through the corresponding processing.

To this end, in the present invention, a service and signaling interface needs to be added between a source AN and a target AN, and the service and signaling interface is added between the source AN and the target AN, which will be described first:

(1) the signaling interface protocol stack may be:

IOS Application, input output system Application;

SCTP or TCP, stream control transmission protocol or transmission control protocol;

IP, IP protocol;

l2, two layers;

physical Layer, Physical Layer;

(2) the service interface protocol stack may be:

user Traffic, User Traffic flow;

RTP/UDP or TCP, real-time transport protocol/user datagram protocol or transmission control protocol;

IP, internet protocol;

link Layer, Link Layer;

physical Layer, Physical Layer.

Based on the interface added between the source AN and the target AN, the source AN sends TCA message to the terminal immediately after receiving the switching start message.

After TCA is sent to the terminal, the source AN and the target AN determine the point of reverse data processing, namely, a certain reverse data frame is taken as a reference to carry out switching processing. The data before reference is processed by the source AN and then sent to the PDSN, and the data after reference is processed by the target AN. When the reference point of the reverse data migration determined by the target AN is smaller than the sequence number of the RLP data expected to be received by the current AN, after the source AN finishes processing the data before the reference point, the data after the received reference point can be transferred to the target AN for processing, and if the source AN does not switch the data after the reference point to the target AN, the target AN requests the terminal to retransmit the data; for real-time traffic, if the source AN does not migrate the data after the reference point to the target AN, this portion of data will be discarded.

For the forward data processing, after the source AN sends the forward data, the last RLP sequence number sent by the source AN side is used as a reference sequence number to be sent to the target AN, and the target AN continues to send the data according to the reference RLP sequence number sent by the source AN after receiving the data without resetting the RLP. The packets with RLP sequence numbers smaller than the reference sequence number in the retransmission request of the terminal are retransmitted by the source AN, and the packets with RLP sequence numbers larger than the reference sequence number are retransmitted by the target AN. And when the cached data of the target AN reaches a certain degree or the terminal can be judged to no longer need retransmission of the source AN, the source AN is informed to empty the cached data.

In the handoff process, if there are multiple RLP instances, the RLP instances may be migrated simultaneously or handed off separately.

After the source AN sends all reverse data to the PDSN, indicating that the target AN can send the reverse data to the PDSN; or the source AN and the target AN simultaneously send reverse data to the PDSN, and the PDSN finishes sequencing, specifically, the reverse data received from the source AN is before and the reverse data received from the target AN is after. For forward data, the source AN informs the target AN that the buffered forward data from the PDSN can be processed after the data which is not sent before the handover is sent.

Meanwhile, the PDSN needs to identify the last data in the GRE (routing encapsulation) header of the last data sent to the source AN, i.e., S-AN; and sending signaling to indicate that the forward data is not sent to the source AN/PCF any more.

The following describes a corresponding handover procedure based on AN interface between a source AN and a target AN with reference to the accompanying drawings, specifically as shown in fig. 2, including:

step 21: the target AN, namely the T-AN starts to carry out the merging processing of the reverse data;

after merging, the T-AN detects SEQ (sequence number) of the received reverse RLP data, when the SEQ > is V (R), the T-AN determines that the data needs to be processed on the T-AN and caches the data, otherwise, the T-AN sends the RLP data to the S-AN for processing;

the T-AN further needs to record SEQ of the first RLP data buffered, and mark it as HO _ SEQ (handover sequence number), so that HO _ SEQ > ═ v (r), and v (r) is a reference point for reverse data handover;

step 22: the T-AN sends AN RLP migration starting message to the S-AN to indicate the S-AN to start RLP data migration operation;

the RLP migration start message comprises HO _ SEQ and is used for indicating that the S-AN only needs to process reverse data of reverse SLP data SEQ < HO _ SEQ when processing the reverse data;

step 23: after receiving the message for starting session migration, the S-AN continues to process the unsent forward data until the last unsent forward data is processed;

meanwhile, the S-AN sorts the received reverse data of SEQ < HO _ SEQ from SLP of T-AN according to SEQ and then sends the data to the PDSN;

step 24: after the S-AN finishes sending the forward data, sending a forward data migration completion message to the T-AN to indicate that the forward data is sent, wherein the message carries a next RLP sequence number V (S) to be sent as AN RLP initial sequence number of the forward data sent by the T-AN, and the RLP initial sequence number is a reference point of forward data switching;

T-AN returns ACK message to S-AN after receiving the message;

it should be noted that, when the target AN receives the data requested to be retransmitted from the terminal and determines that the corresponding data is cached in the source AN, the target AN requests the source AN to retransmit the data; the method for determining the corresponding data to be cached in the source AN is as follows: when the source AN finishes sending the forward data and indicates the target AN to start sending the data, the source AN tells the target AN the RLP sequence number V (S) of the data to be sent, when the target AN sends the forward data, if the sequence number of the data requested to be retransmitted by the terminal is smaller than V (S), the data to be retransmitted is in the source AN, otherwise, the retransmitted data is in the target AN;

if the source AN needs to retransmit the data, the source AN sends the encapsulated RLP data to the target base station so as to send the data to the terminal; or the source AN sends the data to the target AN, and the target AN encapsulates the data and then sends the data to the target base station;

in the target AN, the reference point of the reverse data handover may be smaller than the RLP sequence number of the data currently desired to be received by the source AN, in which case, after the source AN processes the data before the reference point, the unprocessed data after the reference point may be transferred to the target AN for processing, or the target AN requests the terminal to retransmit the data;

for real-time services, when the reference point of reverse data switching is smaller than the RLP sequence number of the data which the source AN currently wants to receive, the reverse data switching is directly discarded or transferred to a target side for processing;

in addition, in the invention, the real-time service has no retransmission processing condition, the target side starts to send the forward data after the source side processes the forward data, and the source side does not need to be requested to retransmit the data.

Step 25: after receiving the forward data migration completion message, the T-AN starts to send data to the terminal;

step 26: the S-AN sends a reverse data migration completion message to the T-AN after finishing sending the reverse data, and indicates that the reverse data is sent completely;

in the session migration process, the S-AN also needs to send reverse data before a reference point of reverse data switching to the PDSN, and after the sending is completed, a reverse data migration completion message is sent to the T-AN;

that is to say, after the S-AN completes processing the forward data or the reverse data that needs to be processed, it needs to send a corresponding forward data or reverse data migration completion message to the T-AN, the time for completing the processing of the two data has no fixed sequence, and the timing relationship shown in fig. 3 is only a specific example; for multiple RLP instances, the migration of RLP instances may be performed through one to multiple signaling.

In the present invention, a processing procedure when the inter-AN handover processing procedure in the active state fails is also provided, as shown in fig. 3, the processing procedure specifically includes the following operation processing procedures:

step 31: the AT sends a routing update message to the source AN, wherein the routing update message comprises neighbor cell information with high signal strength;

step 32: the source AN determines that hard switching is needed according to the routing update message, and then sends a switching request message to the target AN, wherein the message comprises session information related to the AT and target cell information;

step 33: after receiving the switching request message, the target AN verifies the message; if the verification is passed, resources, including channel resources and processing resources, are allocated. And then responds to the reply message.

Step 34: the source AN locks the session configuration of the AT.

Step 35: after the configuration of the locking session, the source AN sends a handover command to the target AN, and the message includes parameters such as the address and the port number of the PDSN.

Step 36: the target AN responds to the reply message and returns the channel assignment parameters to the source AN after receiving the handover command.

Step 37: after receiving the channel assignment switching parameter, the source AN sends a switching start message to the target AN to indicate that the switching has started.

Step 38: after receiving the handoff start message, the target AN establishes AN A8 connection with the destination PCF. The message for establishing A8 may be added with AN indication that AN inter-AN handoff is required to send down data.

Step 39: after the PCF receives the A9-Setup-A8 message, the destination PCF initiates the establishment of an A10 connection to the PDSN.

Step 310: after the connection of A10 is established, the PDSN responds to the A11-registration reply message to the destination PCF;

step 311: the target PCF completes the A10 connection, completes the A8 establishment and feeds back AN A9-Connect-A8 message to the target AN, and the target AN stops the timer TA 8-Setup;

step 312: the PDSN judges that A10 (second A10) established due to switching simultaneously sends data to the target PCF and the source PCF, and adds B-diagnosing Indication information in the GRE packet header of the simultaneously sent data packet to indicate that the data are sent to the target PCF and the source PCF simultaneously; the target PCF receives the data and then forwards the data to the target AN, and the source PCF receives the data and then forwards the data to the source AN;

step 313: the source AN receives the data carrying Bi-casting indication from the PCF, then buffers the part of data, and decides when to send TCA message according to the channel condition and service attribute of the terminal, the assignment parameter carried in the message is transmitted by the target AN;

the specific treatment process comprises the following steps: if the service is the delay sensitive service, sending a TCA message to the terminal immediately, if the service is the non-delay sensitive service and the channel condition is better (namely the channel quality always meets the preset condition), sending the TCA message after sending the cached data (non-retransmission data) which does not carry the Bi-casting indication, and if the channel quality does not meet the preset condition, sending the TCA message immediately; and if the delay and non-delay sensitive service and the non-delay sensitive service exist at the same time, immediately sending the TCA message. For the cached data, the source AN continues to send to the PCF and the PDSN;

step 314: after receiving the TCA message, the terminal automatically restores the cell channel under the source AN if the terminal can not be normally switched to the cell of the target AN;

step 315: the target AN does not receive the channel establishment completion message, and sends a switching failure message to the source AN after the timer is overtime;

step 316: after receiving the switching failure message, the source AN waits for the reverse indication of the terminal, starts to continuously send data with double wave indication and data needing to be retransmitted to the reverse direction after receiving a reverse indication signal recovered by the terminal, and continuously processes the reverse data;

step 317: the source AN responds to the target AN with a switching failure response message;

step 318: the target AN initiates the release of A8/A10 connection, after the PDSN releases A10 connection, the PDSN does not send data to the target AN/PCF any more, and meanwhile, the data sent to the source AN does not carry Bi-casting indication in the GRE packet header any more, namely, the switching process fails, and the data receiving and sending process of the terminal AT returns to the source PCF/AN side for processing.

In summary, it is obvious that the implementation of the present invention can effectively ensure the reliability of data transmission in the process of implementing active inter-AN handover in HRPD network, and can also avoid the transmission of some invalid data (such as data with time delay overtime) from occupying network resources, so the process of the active inter-AN handover provided by the present invention is simple and reasonable.

The above description is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions (including message names that can be arbitrary and the corresponding processing steps that can be different) that can be easily conceived by those skilled in the art within the technical scope of the present invention are also included in the scope of the present invention.

Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A method for performing AN inter-AN handoff in AN active state in a network, comprising:

2. The method of claim 1, wherein when performing handoff between ANs belonging to different PCFs, said step B comprises:

3. The method as claimed in claim 2, wherein the step C further comprises:

4. The method as claimed in claim 3, wherein the step C1 is further executed before the step C1:

5. The method as claimed in claim 4, wherein the step C0 comprises:

6. The method as claimed in any of claims 1 to 5, wherein the step of the target AN sending the delay-sensitive service that has not timed out and all non-delay-sensitive service data to the terminal comprises:

7. The method of claim 6, further comprising:

8. The method of claim 7, wherein the PDSN begins sending reverse data from the target AN at the time point:

or,

9. The method according to any of claims 1 to 5, wherein the step of the source AN sending the buffered valid data to the terminal comprises:

or,

10. A method for enabling AN active inter-AN handover in a network according to any of claims 1 to 5, the method further comprising:

11. The method of any of claims 1-5, wherein the method further comprises:

12. The method as claimed in claim 11, wherein the step D comprises:

13. The method of claim 12, wherein the step D1 comprises:

14. The method of claim 12, wherein the step D2 comprises:

or,

15. The method of claim 14, wherein the step D21 further comprises:

16. The method of claim 12, wherein the step D2 comprises:

or,

17. The method of claim 16, wherein step D further comprises:

18. The method as claimed in claim 17, wherein the step D further comprises:

19. The method of claim 11, wherein step D further comprises:

20. The method of claim 11, wherein the traffic for handover between the source AN and the target AN comprises:

real-time traffic and/or non-real-time traffic.