CN1951036B - Perform switchover by postponing IP address establishment - Google Patents

Abstract

In a broadband wireless access system, when handover is performed while receiving data, a method of deferring IP address establishment procedures is provided to allow such data to be delivered between the base stations. When the terminal receiving downlink data moves from a first base station region to a second base station region, the first base station delivers the downlink data to the second base station, and the second base station uses a particular message to inform that there is data to be delivered to the terminal such that the IP address establishment of the terminal is deferred.

Description

Perform switchover by postponing IP address establishment

technical field

The present invention relates to a method for maintaining data service continuity in a broadband wireless access system, in particular to a method for establishing an IP address of a mobile station for maintaining data service continuity during handover or in idle mode.

Background technique

Generally, in broadband wireless access systems, idle modes for mobile (or fixed) terminals (such as mobile stations, mobile subscriber stations (MSS), user terminals, user equipment (UE), etc.) are supported in order to minimize power consumption . In idle mode, a 'paging area' is defined as the entire area handled by a plurality of base stations called a 'paging group', and all base stations included in the same paging area have the same paging cycle value (paging cycle Paging_cycle, Paging_Cycle) and paging offset value (paging_offset, Paging_Offset).

The terminal can request the base station to change to idle mode, and the base station transmits its paging area identification (paging group ID) and its related paging cycle and paging offset to the terminal to allow the terminal to change to idle mode state. During the idle mode, the terminal may determine whether to maintain or end its idle mode based on paging transmitted from the base station in a broadcast format on each paging cycle.

Furthermore, a terminal can end its idle mode at any time when there is traffic (eg data, packets, etc.) that needs to be transmitted by the terminal in idle mode. In addition, when a terminal in idle mode does not receive paging within a set period of time due to some reasons such as moving to another paging area, losing synchronization, etc., the terminal ends its idle mode.

Hereinafter, a process of a terminal transitioning to an idle mode and a related art method of establishing an IP address when downlink data exists will be explained.

However, in FIG. 1 , a method of transmitting downlink traffic (data) received by a terminal to a registered base station (BS) is not defined in the prior art, that is, from a previous base station (serving BS) to a new base station (BS) Target BS). Furthermore, even if a method of transferring data between base stations is defined, when the terminal re-establishes the IP address, the transferred data will be useless from the perspective of the application program in the terminal.

For example, in Figure 1, if a terminal in idle mode moves into the paging area and is within the area of another base station BS#3, when downlink data arrives at base station BS#1 which performs a registration release for initial transition to idle mode , the base station BS#3 notifies the terminal through a paging message to perform network entry.

Next, data needs to be transmitted from the base station BS#1 where the terminal initially transitioned to idle mode to the base station #3 currently receiving paging, but the prior art does not define the method of this transmission.

In addition, even if the above-mentioned problems are solved, as shown in FIG. 2, in the prior art, since the terminal performs IP address establishment (or re-establishment) based on receiving paging when there is downlink traffic (data), the slave terminal From the point of view, the received data is useless.

Thus, in the above-mentioned operations of the related art, when there is traffic (data) that needs to be transmitted to the terminal in idle mode, a method of receiving data without the terminal performing the IP establishment process is not defined.

Meanwhile, when handover is performed in the broadband wireless access system, the terminal releases the connection with the serving base station (serving BS), and performs handover to the target base station (target BS) to be handed over to. When the terminal performs handover, The mobile terminal handover indicator (MOB-HO-IND) is transmitted to the serving BS, and if the handover indicator type (HO_IND_type) value is '00', it means that the serving BS is released (Serving BS Release, Serving BS Release).

In the prior art, if the handover indicator type (HO_IND_type) value is '00', the serving BS releases all connections, and the state machine and MAC PDU (protocol data unit) of the media control layer (MAC) of the relevant terminal can be neglect. In addition, it is defined that the serving BS can transmit the MAC state machine and MAC PDU to the target base station (target BS) for service continuity, or can be ignored by request via the backbone message of the target base station. However, the specific operations to be performed by the terminal to receive these have not been specified yet.

Accordingly, the present invention defines operations for receiving data transmitted by a previous base station to a target base station after the terminal has moved.

Figures 3 and 4 show two examples of a handover performed by a mobile terminal. As shown in Figures 3 and 4, in the handover process according to the request of the terminal or the request of the base station, after the terminal performs the initialization process of handover, a handover indicator (for example, MOB_HO_Indication) is sent to the base station currently receiving the service (serving base station ), and releases the association (connection) with the base station BS#1 receiving the service. Thereafter, the terminal performs the remaining procedures for accessing the target base station BS#3, that is, paging procedure and initial network entry.

Fig. 5 shows the format of the handover indicator (MOB_HO_Indication). HO_IND_type is set to '00' when the association (connection) with the base station BS#1 receiving the service is released.

Contents of the invention

technical problem

However, in the idle mode of the related art, if the serving base station transmits data to the target base station when the terminal performs handover, if the mobile terminal re-establishes an IP address during data reception, the received data becomes useless. That is, as shown in FIG. 2, regardless of whether there is transmitted data after switching, the terminal performs IP address establishment immediately, and even if transmitted data is sent to the terminal, from the viewpoint of the application program in the terminal, such Data is also useless. Therefore, in this case, it is necessary to clearly define when the establishment of the IP address should be performed, but the prior art fails to do so.

technical solution

In view of the problems in the prior art, when performing handover of the terminal (when the terminal changes its operating mode), data continuity should be maintained, and at the same time, for broadband wireless access systems, it is also necessary to properly perform IP address establishment to ensure that the terminal and the network normal communication between them.

In a broadband wireless access system, when a mobile or fixed terminal in idle mode has downlink data to receive or when handover is performed while receiving the data, the IP address establishment process is postponed (delayed) to allow send the data correctly.

Description of drawings

Figure 1 shows the IP address re-establishment operation when a mobile station transitions to idle mode according to the prior art.

Figure 2 shows the re-establishment of the IP address when a mobile station in idle mode changes to receive mode or when a handover occurs according to the prior art.

Fig. 3 shows an example in which handover is performed based on a request from a mobile station.

Fig. 4 shows an example of performing handover based on a request from a base station.

Fig. 5 shows the format of a handover indicator according to the prior art.

Figure 6 shows the format of a data transfer message used in the present invention.

Fig. 7 shows the format of the data transmission stop message used in the present invention.

Fig. 8 shows an example of a registration response message used in the present invention.

FIG. 9 shows an example of a ranging response message according to the present invention.

FIG. 10 shows a method of transferring data between base stations and delaying IP address assignment of a mobile station according to a first embodiment of the present invention.

Fig. 11 shows the format of the data transfer indicator used in the present invention.

Fig. 12 shows an example of registration response (RNG_RSP) message encoding according to the present invention.

13 shows a method of transferring data between base stations and delaying IP address assignment of a mobile station according to the first embodiment of the present invention, showing IP address establishment when the base station cannot clearly inform the mobile station whether data transfer is possible.

Fig. 14 shows the method of the second embodiment of the present invention, in which IP address establishment is performed when there is no explicit data transfer message from the base station during a certain time.

FIG. 15 shows the method of the second embodiment of the present invention, in which IP address establishment is performed when the base station can clearly notify the mobile station whether data transmission is possible.

FIG. 16 shows an example of a procedure for data transmission after a serving base station transmits an indicator based on a request from a mobile station in the method of the second embodiment of the present invention.

Detailed ways

Preferred embodiments of the present invention will now be explained. However, those skilled in the art should understand that the features of the present invention are not limited to the embodiments described herein.

The present invention is related to research and development conducted by various IEEE working groups, such as IEEE802.16, and as such, the concepts and teachings contained therein are applicable to the features of the present invention. Furthermore, as various efforts are made to achieve interworking of different types of networks and communication technologies, such as achieving compatibility between IEEE networks and cellular networks such as third generation (3G) The invention can also be applied in compatibility.

The Internet Protocol (IP) provides the necessary addressing and routing information for the packets, taking into account the communication protocols related to the wireless access system at the network layer to allow correct communication of data packets via the Internet. Here, each device (eg, user equipment, mobile handset, wireless connectivity device, etc.) connected via the Internet needs to establish a unique IP address in order for the device to be correctly identified and differentiated from other devices.

Internet protocols known as IP version 4 (IPv4) and IP version 6 (IPv6) have been developed. Due to the use of 32-bit addresses, it has been found that each device connected to the Internet requires its own unique IP address due to the increased popularity of Internet communications, and IPv4 has limitations. Also, since the available 32-bit addresses will soon be exhausted, an enhancement, namely IPv6, was developed which utilizes 128-bit addresses.

However, the fact that user terminals can have mobility (e.g. mobile terminals) makes IP address establishment more difficult. For example, to support mobility, user terminals undergo handover whereby a terminal served by one base station covering a defined area moves to new location and needs to be served by a different base station covering that new location. In other words, a mobile station which is part of a first subnet (i.e. part of the network) moves to a second subnet (i.e. another part of the network) Another example is when a user terminal changes its operating state from idle mode to receive mode, said idle mode being an example of a power saving mode of operation, which is important because a user terminal with mobility conserves It's limited battery power.

In the handover or idle mode change situations described above, IP address establishment must be performed at an appropriate time so that the user terminal can receive seamless data reception.

To address the problems of the prior art, in a broadband wireless access system in which a mobile terminal in idle mode moves to the area of a second base station within the paging area of a first base station, the IP address of the mobile terminal is established according to the present invention The method includes: when the downlink data arrives at the first base station, the first base station transmits the downlink data to the second base station through a first message; the second base station notifies the mobile terminal that there is data to be transmitted through a second message; and delaying IP address establishment according to the second message to allow data reception at the mobile terminal.

Preferably, the first message is a data transfer message. Preferably, the method for establishing the IP address of the terminal further includes a step: after the IP address is established, the first base station sends a data transmission stop message to the second base station. Preferably, the second message is a registration response message or a ranging response message. In this case, the registration response message includes a parameter to delay establishment of the IP address of the terminal by notifying that there is data to be transmitted.

To achieve the above object, in a broadband wireless access system in which a mobile terminal receiving downlink data moves to the area of a second base station located in the paging area of a first base station, the establishment of the mobile terminal according to the present invention The method of the IP address includes: by transmitting a switching indicator from the mobile terminal to the first base station, inquiring whether the first base station can transmit downlink data to the second base station; the first base station notifies the mobile terminal via the data transmission indicator whether the data can be transmitted transmitting, and transmitting downlink data to the second base station; and performing an IP address re-establishment procedure after receiving the downlink data from the second base station based on receiving the data transmission indicator.

Preferably, if the first base station cannot explicitly notify the data transfer capability, or if the data transfer indicator is not received within a determined amount of time, the mobile terminal performs an initial network entry, waiting for a timeout for receiving downlink data arrival Determine the amount of time, and then perform the IP address re-establishment process.

To achieve the above object, in a broadband wireless access system in which a mobile terminal receiving downlink data moves to the area of a second base station located in the paging area of a first base station, the establishment of the mobile terminal according to the present invention The method of the IP address includes: the mobile terminal transmits a transmission indicator to the first base station; the first base station transmits the downlink data to the second base station via the data transmission indicator; data to the mobile terminal; and receiving downlink data from the second base station after delaying IP address re-establishment by a determined amount of time in accordance with the first message.

Preferably, the first message is a registration response message or a ranging response message.

In a broadband wireless access system, as the first embodiment, the present invention proposes a method of transmitting data between base stations when there is downlink data to be received by a fixed/mobile terminal in an idle mode, and when A method of postponing (or delaying) the IP address establishment process when the mobile terminal changes to a receive mode for data reception.

That is, the present invention defines that when the mobile terminal transitions to the idle mode and moves from the area of the base station performing the transition process to the area of another base station, after the data arrives at the base station performing the initial idle mode transition process, the transmission of data process to the current base station. Also, if the IP address is changed when the terminal receives the message transmitted through the above-mentioned procedure, the data will be useless and thus the present invention defines the procedures so that the IP address establishment procedure is not performed in the above-mentioned case.

In another embodiment, the present invention provides a method of transferring data between base stations when handover is performed during data reception, and a method of postponing an IP address establishment process after a mobile terminal moves to a new location.

That is to say, in the broadband wireless access system, the present invention provides a method, wherein during the handover of the mobile terminal, the currently serving base station (serving BS) transmits the data being received by the mobile terminal to the desired BS through the backbone network. A target base station (target BS) to which to handover to ensure continuity of service after handover.

Furthermore, the present invention provides a method capable of delaying (delaying or delaying) an IP address establishment process while a mobile terminal receives data transmitted from a previous base station to a new base station after handover is performed.

Furthermore, the present invention provides a method that allows a mobile terminal to perform handover by explicitly knowing whether data currently explicitly received can be received after moving, and defines a message transmitted from a serving base station to a target base station.

In addition, when the mobile terminal completes the handover, the present invention defines a message sent by the target base station to the serving base station, which indicates whether data transmission should be stopped due to the completion of the handover.

First, a method of transferring data between base stations and a method of delaying (delaying) IP address assignment of a terminal according to a first embodiment of the present invention will be explained.

When handover is performed, the serving BS discards MSS-related MAC SDUs (Service Data Units) or forwards MAC SDUs for service continuity. However, the MSS shall decide whether to forward the MAC SDU to the target BS according to the service type. Therefore, the present invention proposes a new method for MSS to request serving MS release with data forwarding. For this reason, the present invention proposes to modify the MOB-HO-IND message format by adding a HO_IND_type for MSS to determine service continuation by forwarding the MAC SDU about the MSS, as shown in FIG. 5 .

In the case of data forwarding, if the MSS re-establishes the IP connection after handover, the forwarded data becomes useless due to the IP address change. Therefore, the MSS should postpone IP re-establishment if there is data forwarded from the serving BS.

If the BS decides whether to forward data and the MSS is not aware of the decision, the MSS requests the release of the serving BS by sending a MOB_HO_IND MACManagement message with a value of HO_IND_type indicating the release of the serving BS to the target BS, which decides whether to forward the data intended for the MSS to Target BS.

Since the MSS does not know whether the serving BS decides to forward the data of the MSS to the target BS, the MSS waits for any forwarded data for some predetermined time after handover. If data is received from the new BS within a predetermined time and is destined for the old IP address, the MSS may choose to defer IP address re-establishment until the session ends. If the MSS chooses to end the session, it establishes IP connectivity to obtain a new IP address.

When the MSS re-establishes IP connectivity, the new BS can send a Stop_Data_Forwarding trunk message to the old BS. When the serving BS receives the Stop_Data_Forwarding backbone message, the BS can close all connections and discard the state machine and MAC SDUs related to the MSS.

If the MSS can explicitly request the serving BS to release with data forwarding, the MSS does not need to wait for a predetermined time to check whether any forwarded data is received after handover. In this case, the BS indicates to the MSS its data forwarding capabilities. If the MSS receives an indication that data forwarding is supported, the MSS postpones re-establishment of the IP connection, and if the MSS receives an indication that data forwarding is not supported, the MSS re-establishes the IP connection after handover without waiting for a predetermined time.

After the MSS re-establishes the IP connection, the new BS can send a Stop_Date_Forwarding trunk message to the old BS. When the serving BS receives the Stop_Date_Forwarding message, the BS can close all connections and discard the MSS state machine and MAC SDU.

If the MSS that can explicitly request data forwarding requests the release of the serving BS by sending a MOB_HO_IND_type MAC Management message with a value of HO_IND_type indicating the release of the serving BS, the MSS will not pay attention to whether the data is forwarded to the target BS. As soon as the handover is completed, the MSS starts The IP is re-established and registered with the new BS.

After the handover request/response handshake has been completed, the MSS can start the actual handover (HO). At some stage during the HO process, the MSS interrupts the service with the serving BS with or without the option of data forwarding. This is done by sending a MOB-HO-IND MACManagement message with HO_IND_type value indicating release from the serving BS for no data forwarding, or MOB-HO-IND indicating HO_IND_type release by the serving BS with data forwarding for forwarding data to the target BS. IND MAC Management message to achieve.

If the HO_IND_type field indicates the serving BS release, the BS can close all connections and discard the MAC state machine and MAC PDUs related to the MSS, and if the HO_IND_type field indicates the serving BS release with data forwarding, it can be kept and forwarded to The connection, MAC state machine and MAC PDU related to the MSS of the target BS are in order to continue the service until the target BS requests the serving BS to stop forwarding through the backbone. When the handover of the MSS is successfully completed, the target BS can buffer forwarded data and transmit to the MSS, and at this time, send a backbone message to tell the serving BS to stop forwarding.

The MSS can request forwarding of currently received data by sending a MOB_HO_IND MAC Management message indicating the HO_IND_type value released by the serving BS with data forwarding. MSS makes this request if it wants to receive data currently received by the serving BS for service continuation, and defers IP re-establishment after handover until the process of currently received data is completed. Based on receiving the HO_IND_type released by the serving BS with data forwarding, the serving BS shall send MOB_FWD_IND to the MSS on the base CID indicating whether the BS can forward data or not. If the action code in MOB_FWD_IND indicates 'do not support data forwarding', the MSS will re-establish the IP address as soon as the handover is completed, and if the action code indicates 'support data forwarding', the MSS will postpone the IP re-establishment and receive the forwarded data. When the MSS re-establishes the IP connection during receiving forwarded data, the BS may send a backbone message to request the old BS to stop forwarding data.

In the first embodiment of the invention, the following messages are defined:

*Data transfer message: A message used by the serving base station when transferring received data when the mobile terminal is not moving to the target base station.

*Data transfer stop message: a message sent by the target base station to the previous base station to request to stop the data transfer via the mobile terminal.

*Registration Response Message: A message that additionally includes a parameter for postponing (delaying or hysteresis) IP address establishment.

*Ranging response message: A message that additionally includes a parameter for postponing IP address establishment by notifying that there is a message to be transmitted to the mobile terminal when the mobile terminal performs a ranging procedure.

6-9 respectively show examples of the above four types of messages, and the parameters used for each message are just examples and thus may be changed.

Here, the data transfer message shown in FIG. 6 may also be referred to as 'MSS-Data-Forwarding Message', which is a message sent from the serving BS to the target BS to forward the MAC SDU of the MSS during HO. This message is usually used when the MSS requests the serving BS to release the serving ZBS and data forwarding. Preferably, upon receipt of the Stop-Data-Forwarding message, the transmission of the message will be stopped, as described below.

The data transmission stop message shown in FIG. 7 may also be called 'Stop-Data-Forwarding Message', which is a message sent from the target BS to the serving BS so that the serving BS stops forwarding the MAC SDU of the MSS.

Next, a method of transferring data between base stations and delaying (delaying or delaying) IP address assignment (establishment) of a terminal according to the first embodiment will be explained with reference to FIG. 10 .

The process used to transfer data between base stations

If the mobile terminal transitions to the idle mode, and the mobile terminal moves from the area of the base station in which the mobile terminal performed the transition process to the idle mode to a different base station area, when data arrives at the base station that performed the initial idle mode transition process (serving BS: BS#1), the base station (BS#1) notifies other base stations (BS#2 and BS#3) that downlink data arrives at a mobile terminal (MSS) having a specific MAC (Medium Access Control) address.

Then, all base stations (BS#2 and BS#3) within the same paging area establish an action code to enter the network by using the MAC address of the paging mobile terminal. The mobile terminal (MSS) that received the paging performs a network entry procedure, and the base station (target BS: BS#3) that performs the network entry procedure notifies the base station (serving BS) that received the above data that there is a paging to it area mobile terminals.

Thus, the base station (BS#1) transmits data to the base station (BS#3) for the mobile terminal to perform network entry. Here, data is transferred by including it in a data transfer message, which is a backbone message.

Defer IP address establishment when performing network entry

When a mobile terminal performs network entry, because it has data to be received, the mobile terminal must postpone (delay) IP address establishment through the following two cases.

First, after being in idle mode, IP address establishment is deferred (delayed or delayed) based on network entry according to the opcode of paging (eg, enter network).

Second, when the base station explicitly performs the registration process or the paging process, the fact that there is data to be transmitted is notified to the mobile terminal through a registration response message or a ranging response message, and the mobile terminal delays (delays or delays) The IP address is established.

In addition, the mobile terminal can establish an IP address during data reception, and when the IP address is established, the base station receiving the data sends a data transmission stop message, which is a backbone message, to the base station transmitting the data.

Next, a method of transferring data between base stations and postponing (delaying or delaying) IP address assignment (establishment) of a mobile terminal according to a second embodiment of the present invention will be explained. The following messages are defined by the first embodiment of the present invention.

*Switch indicator: This indicator requests explicit notification whether the currently received data can be delivered or not.

* Data transfer indicator: This indicator allows the base station to inform the mobile terminal whether data transfer is possible.

*Data transfer message: This message is used when the serving base station transfers to the target base station data that should be received by the mobile terminal when it is not moving.

* Data transmission stop message: This message is used when the target base station requests that the previous base station should stop the data transmission of the mobile terminal.

*Registration Response Message: This message further includes a parameter to postpone IP address establishment by notifying that there is a message to be transmitted to the mobile terminal when the mobile terminal performs a registration procedure.

*Ranging Response Message: This message further includes parameters to postpone IP address establishment by notifying that there is a message to be transmitted to the mobile terminal when the mobile terminal performs the ranging procedure.

Figures 5 and 11A show the formats of the handover indicator and the data transfer indicator, respectively. The formats of the above four types of messages are shown in Figures 6-9 respectively. Here, the parameters for each message are just examples and thus may be changed.

In FIG. 11, MOB_FWD_IND_Message_Format is shown as an example of a data transfer indicator. When the MSS sends a MOB_HO_IND MAC Management message with the HO_IND_type value released by the serving BS with data forwarding, the BS sends this message to indicate its data forwarding capability. Sends an action code of 00 to indicate to the MSS that the BS can forward data to the target BS , and send 01 when the BS cannot support data forwarding.

Fig. 12 shows an example of registration response (RNG_RSP) message encoding according to the present invention.

Referring to Figure 12, during handover (HO), the MSS downlink (DL) data pending element of the HO process optimization TLV item in the RNG-RSP, the target BS can notify the MSS HO through Bit#7 before entering MSS DL data pending status. Upon successful re-entry of the MSS at the target BS (which has now become the new serving BS), and after the new serving BS completes receipt of any retained and forwarded MSS DL data to be sent, the MSS may re-establish IP connectivity , and the new serving BS may send a backbone message to request the old serving BS or other network entities to stop forwarding any MSS DL data pending before HO.

Next, a method of transferring data between base stations and postponing (delaying or delaying) IP address assignment (establishment) of a mobile terminal according to a second embodiment will be explained with reference to FIGS. 12-15. Here, it should be noted that in FIGS. 12-15, the step of releasing the terminal (MSS) is described before the initial MMS data forwarding step. However, the box showing the 'MMS release' step is shown as dashed lines to indicate the specific location of this step throughout the process, which can be changed as desired or if required. For example, the MSS release step can be performed near the end of the overall process rather than in the initial steps if it is more beneficial to do so.

In addition, in FIGS. 12-14, it should be noted that the data forwarding step can be continuously performed until the serving BS receives a message (Stop-Data-Forwarding) indicating that the data forwarding should be stopped from the target BS.

Moreover, since the features of the present invention have been described for the transfer (forwarding) of data between base stations, it will be appreciated that such data transfer (forwarding) can be performed directly between base stations or via intermediate network elements, such as access gateways , to proceed. In other words, as shown in FIG. 2, a part of the network (eg, a backbone) may include at least two base stations directly connected together or at least two base stations connected to each other via a gateway (or other network element). When the base station cannot clearly notify the terminal of the data transmission capability

Figure 13 shows the IP address establishment when the base station cannot explicitly inform the mobile terminal whether it can transmit data or not.

Referring to Fig. 13, if there is data currently being received, the mobile terminal sets HO_IND_type of MOB-HO-IND to '00' (=serving BS release) and transmits, or sets '11' (=serving BS release with data forwarding ) and can be sent to the base station (BS#1). If HO_IND_type is '00', the mobile terminal performs handover without expecting to receive an explicit data transfer indicator from the base station.

In this case, the terminal cannot know whether the previous base station (BS#1) can transmit data to the new base station (BS#2). Thus, after handover, the mobile terminal re-establishes the IP address after waiting a determined amount of time to see if there has been any data to transmit from the previous base station (BS#1). If there is data transmitted during a determined amount of time, the mobile terminal can postpone (delay) IP address establishment to receive the data, can stop data reception at any time, decide to receive data over a new path, and when IP re-establishment occurs , the new base station (BS#2) detects this and transmits a data transmission stop message to the previous base station (BS#1).

Based on the reception of the above-mentioned data transmission stop message, the previous base station stops the message being transmitted, releases (cancels) the state machine of the MAC of the mobile terminal related to the movement and thereafter ignores the MAC SDU transmitted from the upper layer.

Figure 14 depicts IP address establishment when the base station does not provide explicit data transfer messages.

Referring to FIG. 14, if the mobile terminal sends HO_IND_type as '11', it means that the mobile terminal expects the base station to explicitly notify whether data transfer will be made, and if the data transfer indicator is received from the base station, the mobile station communicates with when the base station can clearly Notification can be performed in the same way as data transmission, as shown in Figure 15.

However, if the base station does not support the data transfer indicator, the mobile station waits for a certain amount of time, and if the data transfer indicator is not received from the base station, performs subsequent operations in the same manner as when HO_IND_type is '00'.

When the base station can clearly notify the terminal of the data transmission capability

FIG. 15 describes IP address establishment when the base station can explicitly inform the mobile terminal whether data transmission is possible.

As shown in Figure 15, when the mobile terminal has data currently being received, when set to '11' (=serving BS release with data forwarding), the HO_IND_type of MOB-HO-IND can be sent in order to obtain from The base station receives an explicit indicator of whether data transfer is possible. If the base station (BS#1) supports HO_IND_type of the handover indicator (MOB-HO-IND), the base station (BS#1) transmits a data transfer indicator (MOB_FWD_IND) to the mobile station. Thus, the mobile station receiving the data transfer indicator (MOB_FWD_IND) performs an IP address re-establishment procedure after accepting data currently being received.

When notifying a new base station whether there is data to transmit

FIG. 16 describes the process of sending an indicator to a serving base station to transmit data upon request of an explicit indicator by a mobile station.

Referring to FIG. 16, when a mobile station that is receiving data moves, and when a new base station (BS#2) receives transmission data for a terminal to be handed over from a previous base station (BS#1), after the mobile terminal is handed over When the ranging procedure is performed, or when the registration procedure is performed, the new base station (BS#2) notifies the fact to the mobile terminal so that the mobile terminal postpones IP address establishment.

As described above, when a mobile terminal moves from the zone of a first base station in which an initial idle mode transition is made to the zone of a second base station and attempts to receive data, the present invention defines the procedure for transferring the received data from the first base station to the second base station. process, and defines a method for the mobile terminal to postpone the IP address establishment process in order to receive the above data, so as to achieve the effect of effectively executing data transmission.

In addition, the present invention has a method of transferring data between base stations after handover, and provides a mobile terminal by deferring IP address re-establishment when the mobile terminal receives data transferred from a previous base station to a new base station, so that service continuity can be guaranteed. Effect.

The present invention has been described above for wireless access technologies, and it should be clearly understood that various wireless access technologies currently being developed (such as WiMax, WiBro, Wi-Fi, etc.) can all benefit from the features and teachings of the present invention, They are applicable due to similarities involved in wireless communications involving user terminal mobility, handover and idle mode operation.

The foregoing preferred embodiments are provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments. Thus, the present invention is not limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (22)

1. changing method that is used for BWA, this method comprises:

When having session connection between mobile radio station and serving BS, the switching of determining mobile radio station is necessary;

From serving BS notification target base station: after switching, keep session by target BS;

Carry out handoff procedure to be associated by mobile radio station with target BS;

Notify mobile radio station from target BS: exist the mobile radio station down link data to wait to send out an element; With

Change the Internet protocol addressing if desired, then, postpone the Internet protocol addressing having received after down link data waits to send out element.

2. the method for claim 1 is wherein carried out described determining step by mobile radio station or by network entity.

3. the method for claim 1 is wherein carried out described postponement step by mobile radio station.

4. the method for claim 1 further comprises step:

Carry out new Internet protocol addressing or rebulid the internet protocol address by mobile radio station; With

Transmit transfer of data from target BS to serving BS and stop trunk message.

5. the method for claim 1, wherein the mobile radio station network that relates to mobile radio station that is associated with target BS enters or reenters.

6. the method for claim 1, wherein said handoff procedure comprise range finding and registration.

7. the method for claim 1, wherein said session comprises by the data forwarding of target BS to mobile radio station.

8. the method for claim 1, wherein said serving BS is previous serving BS, and described target BS is new serving BS.

9. the method for claim 1, wherein said BWA comprises IEEE network and cellular network.

10. changing method that is used for BWA, this method comprises:

When having session connection between mobile radio station and serving BS, it is necessary determining to switch;

By mobile radio station notification target base station, the serving BS that has the data forwarding indication with execution discharges;

From serving BS notification target base station: after switching, keep session by target BS;

Carry out handoff procedure to be associated by mobile radio station with target BS;

Notify mobile radio station from target BS: exist the mobile radio station down link data to wait to send out an element; With

Change the Internet protocol addressing if desired, then after receiving downlink data waits to send out element, postpone the Internet protocol addressing.

11. method as claimed in claim 10 is wherein carried out described determining step by mobile radio station or by network entity.

12. method as claimed in claim 10 is wherein carried out by mobile radio station and is postponed step.

13. method as claimed in claim 10 further comprises step:

Carry out new Internet protocol addressing or rebulid the internet protocol address by mobile radio station; With

Transmit transfer of data from target BS to serving BS and stop trunk message.

14. method as claimed in claim 10, wherein the mobile radio station network that relates to mobile radio station that is associated with target BS enters or reenters.

15. method as claimed in claim 10, wherein said handoff procedure comprise range finding and registration.

16. method as claimed in claim 10, wherein said session comprise by the data forwarding of target BS to mobile radio station.

17. method as claimed in claim 10, wherein said serving BS are previous serving BSs, described target BS is new serving BS.

18. method as claimed in claim 10, wherein said BWA comprises IEEE network and cellular network.

19. one kind is moved the method that retaining data during receives at mobile radio station in BWA, this method comprises:

When from the serving BS receiving downlink data, between serving BS and target BS, carry out switching for mobile radio station;

By the indication that other down link data will be transmitted in mobile radio station receiving target base station, this other down link data is with before relevant from the down link data of serving BS reception;

Postpone the internet protocol address by mobile radio station and set up, up to having received described other down link data; With

Receive described other down link data by mobile radio station from target BS.

20. method as claimed in claim 19 after having received described other down link data, further comprises step: set up based on the internet protocol address, rebulid the Internet protocol connectivity.

21. one kind is moved the method that retaining data during transmits at mobile radio station in BWA, this method comprises:

When with down link data when serving BS sends to mobile radio station, between serving BS and target BS, carry out switching for mobile radio station;

The indication that target BS will be transmitted other down link data sends to mobile radio station, and this other down link data is with before relevant from the down link data of serving BS reception;

Send described other down link data from target BS to mobile radio station, this mobile radio station is postponed the internet protocol address and is set up, up to receiving described other down link data fully.

22. method as claimed in claim 21 after having sent described other down link data, further comprises step: set up based on the internet protocol address, cooperate to rebulid the Internet protocol connectivity with mobile radio station.

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