KR20080089729A - Re-entry method on broadband wireless access system and mobile terminal supporting the same - Google Patents

Abstract

A method for net reconnection in a broadband wireless connection system and a mobile terminal supporting the same are provided to secure prompt network reconnection by storing necessary connection information in a nonvolatile storage area at the time of initial network connection and reusing the stored information at the time of network reconnection. Connection information, which a mobile terminal obtains during an initial network connection process, is stored/updated in a nonvolatile storage area(S203). When reconnection to the same network is started between a releasing time of initial connection and a predetermined time, reconnection is performed by using the connection information(S206). If the reconnection is performed between the releasing time of initial connection and the predetermined time, a message of requesting the optimization of reconnection is transmitted to a base station, and then a necessary connection procedure is performed according to the optimization of reconnection of the base station.

Description

Re-entry method on broadband wireless access system and mobile terminal supporting the same}

1 is a flowchart illustrating a conventional first network entry procedure of a broadband wireless access system.

2 is a signal flowchart sequentially illustrating a process of reconnecting to the same base station before the access information maintenance timer expires.

3 and 4 are signal flow diagrams sequentially illustrating a process of reconnecting to the same base station after the access information maintenance timer expires.

5A and 5B are signal flow diagrams sequentially illustrating a process of reconnecting to the same base station when it is unknown whether the access information maintenance timer ends.

6 is a signal flowchart sequentially illustrating a process of reconnecting to a new base station before the access information maintenance timer expires.

7 and 8 are signal flow diagrams sequentially illustrating a process of reconnecting to a new base station after the access information maintenance timer expires.

9A and 9B are signal flow diagrams sequentially illustrating a process of reconnecting to a new base station when it is unknown whether the access information maintenance timer ends.

FIG. 10 conceptually illustrates an error of a connection information maintenance timer that may occur between a mobile terminal and a base station.

FIG. 11 is a signal flowchart sequentially illustrating a process of synchronizing a connection information maintaining timer before network disconnection.

12 is a signal flow diagram sequentially illustrating a process of asking whether current connection information of a current terminal exists in the same base station after network disconnection.

FIG. 13 is a signal flow diagram sequentially illustrating a process of asking whether a new base station has access information of a current terminal after network release.

14 is a block diagram showing the configuration of a mobile terminal of the present invention.

The present invention relates to a method for quickly performing network reentry in a broadband wireless access system and a mobile terminal supporting the same.

1 is a flowchart illustrating a conventional initial network entry procedure in a broadband wireless access system.

When the mobile terminal is powered on for the first time, it first searches whether there is a valid downlink channel (S101). In operation S102, a downlink map message (DL-MAP) and an uplink map message (UL-MAP) message are received from the base station, and downlink synchronization and uplink synchronization are respectively adjusted. Then, downlink channel descriptor (Downlink Channel Description); Receives a DCD) message and an Uplink Channel Description (UCD) message to complete the physical channel setup for the downlink channel and the uplink channel, and interprets various information transmitted through the uplink channel and the downlink channel. Use to

The mobile station performs initial ranging with the base station to adjust parameters for uplink transmission such as timing offset and transmission power, and basic management connection identifier required for transmission of various management messages (Basic). management CID) and a first management connection identifier (Primary management CID) are allocated (S103).

The mobile terminal checks the transmission modes currently supported by the mobile terminal and the transmission modes supported by the base station through message exchange with the base station, and sets a communication mode to be performed in this access (S104).

The mobile terminal performs mutual authentication with the base station to determine whether they are compatible with each other, and when determined to be suitable, generates and exchanges encryption keys (S105). Subsequent transmission messages may include a message authentication code generated through the encryption key so that the base station may perform authentication on the message transmitted by the terminal.

The mobile terminal receives a network entry from a network service provider (NSP) of the network to which the base station belongs, and then receives a second management connection identifier (Secondary management CID) from the base station (S106).

The mobile terminal receives an IP address for transmitting an IP packet from a DHCP server (S107), and updates the current date and time through communication with a time server (S108). In operation S109, the TFTP server receives a system configuration file including information for operating the mobile terminal.

The base station allows a service provider to generate a pre-provisioned service flow for providing a specific service to the mobile terminal so that the service provider can provide a pre-provisioned service for the mobile terminal. (S110).

Conventionally, when the mobile terminal initially connected to the network is disconnected from the network and attempts to connect again (Network Re-entry), the same steps as those of the initial network connection, that is, the steps S101 to S110 described above are the same. Run it all. That is, the same network entry time is required for the initial connection and reconnection, so the continuity of the network connection cannot be guaranteed in a communication environment in which the network connection is frequently released, and resources are unnecessary for reconnection even when viewed throughout the communication system. It tends to be wasted.

In order to solve the above problems, it is proposed to ensure fast network reconnection by storing predetermined access information required for initial network access in a nonvolatile storage space of the terminal and reusing the stored information when reconnecting.

One aspect for achieving the above object is, by the mobile terminal to store the predetermined connection information obtained in the initial network connection process in a nonvolatile storage area, and when the initial connection is released, by using the stored connection information The present invention relates to a network reconnection method in a broadband wireless access system including a step of performing reconnection.

According to another aspect of the present invention, there is provided a method in which a mobile station stores predetermined access information acquired in an initial access procedure to a first base station in a nonvolatile storage area, and the initial access is released and a reconnection is started to a second base station. In this case, the present invention relates to a network reconnection method in a broadband wireless access system comprising performing reconnection by using the stored connection information.

Another aspect of the present invention provides a non-volatile memory for storing predetermined connection information acquired during an initial network connection, a timer for measuring an elapsed time from when the initial connection is released, and a memory stored in the memory. The present invention relates to a mobile terminal performing network reconnection in a broadband wireless access system including a control unit performing reconnection using access information.

In still another aspect of the present invention, there is provided a non-volatile memory for storing predetermined access information obtained during an initial access process to a first base station, a timer for measuring an elapsed time from when the initial access is released; The present invention relates to a mobile terminal performing network reconnection in a broadband wireless access system including a control unit for reconnecting to a second base station using the access information stored in the memory.

Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings.

When the connection between the mobile terminal and the base station is released, the connection termination procedure is normally performed, such as when the power is turned off by the user, the power is terminated due to low battery, or when the base station instructs the terminal to initialize or connects to another base station. The first case that can be performed may be divided into a second case where the connection is abnormally terminated, such as disconnection due to sudden power off or sudden deterioration of the connection environment. In particular, there is a difference in that the previous connection information is not maintained in the mobile terminal in case of sudden power-off in the second case.

The base station periodically checks the flow of uplink data transmission of the mobile station to check whether the mobile station is in a connected state. If the mobile station is determined to be in an unconnected state, the base station performs a resource retaining timer. To start. At this time, the mobile terminal also starts its own connection information maintenance timer when the base station is disconnected. Since an error may occur between the access information maintenance timer of the base station and the access information maintenance timer of the mobile terminal for various reasons, a technique for synchronizing the two is required. The connection information maintenance timer mentioned below indicates a synchronized timer in which the error is corrected, and a method of correcting the error will be described later.

The base station resumes communication with the mobile terminal if the data flow of the mobile terminal is detected again before the access information maintenance timer expires, but if the data flow of the mobile terminal is not detected until the access information maintenance timer expires, It no longer maintains connection information. Therefore, the first case and the second case may be divided into cases before or after the connection information maintenance timer ends.

In addition, the first case and the second case may be divided into a case where the base station to which the mobile terminal will perform reconnection is the same as the case where the base station is not the same as the previous base station.

On the other hand, in order to quickly reconnect, it is necessary to save the previous access information with the network including the base station in the storage space of the mobile terminal in advance, and reuse the valid information among them in order to omit the redundant reconnection procedure. In particular, the access information is preferably stored in a nonvolatile storage space in preparation for an abnormal termination such as an unexpected power shutdown, and is always kept up to date by performing an update whenever all or part of the stored access information is changed. It is desirable to.

The information to be stored in the nonvolatile storage space by the mobile terminal can be classified into two types.

First, information about a currently connected base station and neighbor base stations including DCD, UCD information. Such base station information is periodically transmitted to all terminals currently connected to the base station by the base station.

Secondly, when the terminal accesses the base station, the access information between the base station and the terminal is generated through message transfer between the base station and the terminal. Such access information includes 1) Basic Capability Information, 2) Authentication Keys and Message Authorization Keys, and 3) Operation Parameters. When the connection information is disconnected between the base station and the mobile terminal, it is determined whether the base station maintains the information by the resource information retainer (Resource Retain Timer).

Hereinafter, a procedure of performing reconnection in the above-described combination of various cases will be described in detail according to circumstances.

Network reconnection method in broadband wireless access system

First, Embodiments 1 to 3 below describe a case in which the mobile terminal reconnects to the same base station as the base station before disconnection.

<Example 1>

This embodiment relates to the case where the mobile terminal reconnects to the base station before the access information maintenance timer expires. 2 is a signal flowchart sequentially illustrating a reconnection process in this case.

The base station periodically transmits DL-MAP, UL-MAP, DCD, and UCD messages to the mobile terminal (S201). The mobile terminal receives the messages when the power is turned on by the user, and sets timing parameters and physical channel settings by setting related parameters so as to exchange information through uplink and downlink using the information of the corresponding messages. .

The mobile terminal stores base station information including the base station including the DCD and UCD information in its nonvolatile storage space in preparation for a subsequent reconnection (S202).

The mobile terminal performs data communication with the base station after performing the series of initial network entry processes S102 to S110 of FIG. 1 (S203). At this time, the basic performance information, the authentication key and the message authentication code, the operation parameters, etc. of the terminal obtained during the first entry into the network or communicating with the base station are also stored in the nonvolatile storage space. On the other hand, whenever any one or more of the access information is updated and delivered from the base station, it is preferable to update the information.

When the connection with the base station is released due to power off of the mobile terminal or deterioration of the link state (S204), the base station monitors the mobile terminal for a predetermined time and maintains the access information for the mobile terminal if no data flow is detected. Start the timer (S205).

When the power of the mobile terminal is turned on or the link condition improves, re-connection procedure is started while performing channel search with the base station again (S206).

That is, the mobile station receives the DL-MAP and UL-MAP messages from the base station, and stores configuration change count values of DCD and UCD previously stored before disconnection and the received DL-MAP and UL-. Compare the DCD count and UCD count of the MAP. If both are the same, since the pre-stored DCD and UCD information is valid, the base station including the pre-stored DCD and UCD information is used without waiting for a new DCD and UCD message from the base station (S207). However, if the DCD, UCD information stored in the mobile terminal is invalid, the base station receives the DCD, UCD message again.

However, since the access information maintenance timer expires, the mobile terminal checks whether the previously stored access information is valid. If all access information is valid, the mobile terminal immediately reconnects to the base station without performing a separate access procedure again (S208). If part of the access information is not valid, the terminal reconnects to the base station after further performing a procedure for requesting the corresponding information.

<Example 2>

This embodiment describes the case where the mobile terminal reconnects to the base station after the access information maintenance timer expires. However, even if the access information maintenance timer expires, the base station may continue to maintain the access information of the terminal for a predetermined time according to the network management policy. FIG. 3 illustrates a case in which the entire initial network access procedure is repeated immediately after the access information maintenance timer is disregarded and the above-described possibility is repeated. FIG. In this case, RNG-REQ is sent to skip certain procedures.

First, the case of FIG. 3 will be described.

Steps S301 to S305 are the same as steps S201 to S205 described above, and a description thereof will be omitted.

When the power of the mobile terminal is turned on or the link condition is improved, the procedure for reconnection is started while performing channel search with the base station again (S307), but after the connection information maintenance timer has already expired (S306).

The mobile station receives the DL-MAP and UL-MAP messages from the base station, and stores configuration change count values of DCD and UCD previously stored before disconnection, and the received DL-MAP and UL-MAP. Compare DCD count and UCD count. If both are the same, since the pre-stored DCD and UCD information is valid, the base station including the pre-stored DCD and UCD information is used without waiting for a new DCD and UCD message from the base station (S308). However, if the DCD, UCD information stored in the mobile terminal is invalid, the base station receives the DCD, UCD message again.

However, since the access information maintenance timer expires and the access information previously stored in the mobile terminal is no longer valid, all subsequent initial network entry procedures are performed again (S309).

Next, the case of FIG. 4 will be described.

Since the steps S401 to S408 are the same as the above-described steps S301 to S308, description thereof will be omitted.

When the power of the mobile terminal is turned on or the link condition is improved, the procedure of reconnection is started while performing channel search with the base station again, but the access information maintenance timer has already expired. However, even when the access information maintenance timer expires, the access information may still remain in the base station, and thus the mobile station transmits a predetermined message requesting network re-entry optimization to the base station. The RNG-REQ message can be used as such a message. In this case, it is preferable that the message includes a message authorization code for authenticating the validity of the mobile terminal.

Upon receiving the RNG-REQ message, the base station checks whether it is storing access information of the mobile terminal (S409). If there is access information, the base station examines the message authentication code of the RNG-REQ message to determine whether it is valid, and if it is a valid message authentication code, makes an optimization decision on reconnection of the mobile terminal. Such an optimization decision may set the HO process optimization parameter to a specific value suitable for the situation of the corresponding mobile terminal and notify the mobile terminal of this through an RNG-RSP message. Table 1 shows an example of setting values for each item of the handover process optimization parameter.

Name Type (One byte ) Length Value  ( variable - length ) HO Process Optimization 21 2 For each Bit location, a value of '0' indicates the associated re-entry management messages shall be required, a value of '0' indicates the re-entry man-agement message may be omitted. Bit # 0: Omit SBC-REQ management messages during current re-entry processing Bit # 1: Omit PKM Authentication phase except TEK phase during current re-entry processing Bit # 2: Omit PKM TEK creation phase during re-entry processing Bit # 3 : Omit Network Address Acquisition man-agement messages during current reentry pro-cessing Bit # 4: Omit Time of Day Acquisition management messages during current reentry processing Bit # 5: Omit TFTP management messages during current re-entry processing Bit # 6: Full service and operational state transfer or sharing between Serving BS and Target BS (ARQ, timers, counters, MAC state machines, etc.) Bit # 7: post-HO re-entry MS DL data pending at target BS Bit # 8: BS shall send an unsolicited SBC-RSP management message with updated capabilities information in case capabilities of Target BS are different from the ones of Serving BS Bit # 9: Omit REG-REQ management message during current re-entry processing Bit # 10: BS shall send an unsolicited REG- RSP management message with updated capabilities information Bit # 11: (Target) BS supports virtual SDU SN. If Bit # 11 = 1 and MS supports SDU SN, it shall issue SN_REPORT upon completion of HO to this BS. Bit # 12: MS shall send Bandwidth Request header with zero BR as a notification of MS's successful re-entry registration. Bit # 13: If this bit is set to 1, MS shall trigger a higher layer protocol required to refresh its traffic IP address (e.g. DHCP Discover [IETF RFC 2131] or Mobile IPv4 re-registration [IETF RFC 3344]). Bit # 14-15: Reserved

On the other hand, if the user does not store the access information of the mobile terminal or if the message authentication code is not valid, the mobile terminal can be instructed to perform the initial network access procedure again through a predetermined message. Such an indication may be implemented by transmitting an RNG-RSP message with all of the handover process optimization parameters set to 0 to the mobile terminal.

In addition, the base station may not transmit a response message to the RNG-REQ message (not shown in the figure). In this case, the mobile station starts a separate timer at the same time as transmitting the RNG-REQ message to the base station, and if there is no response message from the base station for a predetermined time, the base station does not store the access information of the mobile terminal or the message It is determined that the authentication code is invalid.

The mobile terminal receiving the former RNG-RSP message performs reconnection by performing only some connection procedures necessary according to the reconnection optimization decision of the base station among the network access procedures (S410). The mobile terminal which receives the latter RNG-RSP message or the response message from the base station for a predetermined time re-connects to the base station by performing the initial network access procedure again.

<Example 3>

This embodiment relates to a case in which a mobile terminal cannot perform a normal connection termination procedure such as a connection release due to a sudden power off or a connection release due to a sudden deterioration of a communication environment, and thus does not know its own connection information maintenance timer information. In this case, similarly to the second embodiment, the access information may or may not remain valid in the base station. Therefore, the mobile station sends a predetermined message (eg, RNG-REQ) to the base station to inquire whether the access information is valid or whether to perform an optimization procedure for network reentry, and proceeds with the reconnection procedure according to the response message.

5A and 5B sequentially illustrate the reconnection procedure according to the third embodiment. In particular, FIG. 5A illustrates a case of notifying whether the RNG-REQ message is valid as an RNG-RSP message, and FIG. 5B illustrates whether the RNG-REQ message is valid as a predetermined time without a response message. The case is shown.

Since steps S501 to S504 are the same as the above-described steps S401 to S404, description thereof will be omitted.

When the power of the mobile terminal is turned on or the link condition is improved, the procedure for reconnection is started while performing channel search with the base station again (S505).

That is, the mobile terminal receives the DL-MAP and UL-MAP messages from the base station, and stores configuration change count values of DCD and UCD previously stored before disconnection, and the received DL-MAP and UL-. Compare the DCD count and UCD count of the MAP. If both are the same, since the pre-stored DCD and UCD information is valid, the base station including the pre-stored DCD and UCD information is used without waiting for a new DCD and UCD message from the base station (S506). However, if the DCD, UCD information stored in the mobile terminal is invalid, the base station receives the DCD, UCD message again.

However, since the mobile terminal cannot know its access information maintenance timer information due to an unexpected disconnection, the mobile terminal inquires whether to store valid access information or performs a network re-entry optimization procedure accordingly. Send the requested message. The RNG-REQ message can be used as such a message. In this case, it is preferable that the message includes a message authorization code for authenticating the validity of the mobile terminal. Since the following procedure is the same as the above-described S409 to S410 will not be described.

Next, Embodiments 4 to 6 below relate to a case where the mobile terminal reconnects to a second base station different from the first base station before disconnection.

<Example 4>

This embodiment describes a case where the mobile terminal reconnects to the base station before the access information maintenance timer expires, but reconnects to a second base station different from the previously connected first base station.

FIG. 6 is a signal flowchart sequentially illustrating a reconnection procedure of Embodiment 4. FIG.

The first base station periodically transmits a DL-MAP, UL-MAP, DCD, UCD message to the mobile terminal (S601). The mobile terminal receives the messages when the power is turned on by the user, and performs synchronization and physical channel setting by adjusting related parameters so as to exchange information through uplink and downlink using the information of the corresponding messages.

The mobile terminal stores base station information including DCD and UCD information of the first base station in its nonvolatile storage space in preparation for a subsequent reconnection (S602).

Meanwhile, the second base station located in the neighborhood of the first base station transmits to the base station first base station including its own DCD and UCD information, and the first base station receiving the base station transmits the received information through a predetermined message (for example, a MOB_NBR-ADV message). Deliver to mobile terminal. The mobile terminal also stores DCD and UCD information of the second base station in the nonvolatile storage space (S603).

The mobile terminal performs data communication with the first base station after performing the series of initial network entry processes S102 to S110 of FIG. 1 (S604). At this time, the connection information (previous connection info.) Of the terminal obtained during the first entry into the network or communicating with the first base station is also stored in the nonvolatile storage space. Also in this case, it is preferable to update the information whenever at least one of the access information is updated and transmitted from the first base station.

When the connection with the first base station is released due to the power of the mobile terminal being turned off or the deterioration of the link state (S605), the first base station monitors the mobile terminal for a predetermined time and if the data flow is not detected, the mobile station is connected to the corresponding mobile terminal. The connection information maintenance timer is started (S606).

When the power of the mobile terminal is turned on again or the link condition improves, a procedure for reconnection is started while performing channel search again with the second base station to which the mobile station belongs (S607).

That is, the mobile station receives the DL-MAP and UL-MAP messages from the second base station, and stores configuration change count values of DCD and UCD previously stored before disconnection and the received DL-MAP and UL. -Compare the DCD count and UCD count of the MAP. If both are the same, since the pre-stored DCD and UCD information is valid, the base station including the pre-stored DCD and UCD information is used without waiting for a new DCD and UCD message from the second base station (S608). However, if the DCD, UCD information stored in the mobile terminal is not valid, the DCD, UCD message is transmitted again from the second base station.

Subsequently, the mobile terminal transmits a predetermined message for requesting network re-entry optimization to the second base station. The RNG-REQ message can be used as such a message. In this case, it is preferable that the message includes a message authorization code for authenticating the validity of the mobile terminal.

When the second base station that has received the RNG-REQ message requests the first base station for access information of the mobile terminal, the first base station transmits the stored access information to the second base station. In this case, since the access information maintenance timer of the first base station is before the end, the access information is still valid.

Subsequently, the second base station examines the message authentication code of the received RNG-REQ message to determine whether it is valid, and if it is a valid message authentication code, makes an optimization decision on reconnection of the mobile terminal (S609). Such an optimization decision may be notified to the mobile terminal through an RNG-RSP message.

On the other hand, if the message authentication code is not valid, the mobile terminal may be instructed to perform the initial network access procedure again through a predetermined message. Such an indication may be implemented by transmitting a RNG-RSP message in which all HO process optimization parameter values are set to 0 to the mobile terminal.

In addition, the second base station may not transmit a response message to the RNG-REQ message (not shown in the figure). In this case, the mobile terminal starts a separate timer at the same time as transmitting the RNG-REQ message to the second base station, and determines that the message authentication code is invalid when there is no response message from the second base station for a predetermined time. .

The mobile terminal which has received the former RNG-RSP message performs reconnection by performing only a partial access procedure necessary according to the reconnection optimization decision of the second base station among network access procedures (S610). The mobile station, which has received the latter RNG-RSP message or has not received a response message from the second base station for a predetermined time, performs all initial network access procedures again and reconnects to the second base station.

Example 5

This embodiment describes a case in which the mobile terminal reconnects to the base station after the access information maintenance timer expires, but reconnects to a second base station different from the first base station to which the mobile station previously connected. However, even if the access information maintenance timer expires, the first base station may continue to maintain the access information of the terminal for a predetermined time according to the network management policy. Accordingly, the second base station can receive the access information that is still valid from the first base station and use it for reconnection.

FIG. 7 illustrates a case in which the entire initial network access procedure is immediately repeated after disregarding the above possibility when the access information maintenance timer expires.

Since the steps S701 to S706 are the same as the above-described steps S601 to S606, description thereof will be omitted.

When the power of the mobile terminal is turned on or the link condition is improved, the procedure of reconnection is started while performing channel search with the second base station again (S708), but the access information maintenance timer of the first base station is already expired (S707). .

The mobile station receives the DL-MAP and UL-MAP messages from the second base station, and receives configuration change count values of DCD and UCD of the second base station previously stored before disconnection and from the second base station. Compares the DL-MAP, UL-MAP DCD count and UCD count. If both are the same, since the pre-stored DCD and UCD information is valid, the base station including the pre-stored DCD and UCD information is used without waiting for a new DCD and UCD message from the second base station (S709). However, if the DCD, UCD information stored in the mobile terminal is not valid, the DCD, UCD message is transmitted again from the second base station.

However, since the access information maintenance timer of the first base station expires and the access information previously stored in the mobile terminal is no longer valid, all subsequent initial network entry procedures are performed again (S710).

FIG. 8 illustrates a case in which a mobile station sends a predetermined message (eg, RNG-REQ) for requesting network entry optimization to a second base station to omit certain procedures for network re-entry.

Since steps S801 to S809 are the same as the above steps S701 to S709, description thereof will be omitted.

When the mobile terminal is powered on or the link condition improves, the reconnection procedure is started while performing channel search with the second base station to which the mobile station currently belongs, but the access information maintenance timer of the first base station has already expired. However, even if the access information maintenance timer expires, valid access information may still remain in the first base station, and thus the mobile station transmits a predetermined message for requesting network re-entry optimization to the second base station. The RNG-REQ message can be used as such a message. In this case, it is preferable that the message includes a message authorization code for authenticating the validity of the mobile terminal.

Upon receiving the RNG-REQ message, the second base station requests access information of the mobile terminal from the first base station, and if the access information of the mobile terminal exists. The first base station transmits the access information stored in the first base station to the second base station.

Subsequently, the second base station examines the message authentication code of the received RNG-REQ message to determine whether it is valid, and if it is a valid message authentication code, makes an optimization decision regarding reconnection of the mobile terminal (S810). Such an optimization decision may be notified to the mobile terminal through an RNG-RSP message.

On the other hand, if the message authentication code is not valid, the mobile terminal may be instructed to perform the initial network access procedure again through a predetermined message. Such an indication may be implemented by transmitting a RNG-RSP message in which all HO process optimization parameter values are set to 0 to the mobile terminal.

In addition, the second base station may not transmit a response message to the RNG-REQ message (not shown in the figure). In this case, the mobile terminal starts a separate timer at the same time as transmitting the RNG-REQ message to the second base station, and determines that the message authentication code is invalid when there is no response message from the second base station for a predetermined time. .

The mobile terminal receiving the former RNG-RSP message performs reconnection by performing only some access procedures necessary according to the reconnection optimization decision of the second base station among network access procedures (S811). The mobile station, which has received the latter RNG-RSP message or has not received a response message from the second base station for a predetermined time, performs all initial network access procedures again and reconnects to the second base station.

<Example 6>

In this embodiment, since the mobile terminal cannot perform the normal connection termination procedure such as disconnection due to sudden power off or disconnection due to sudden deterioration of the communication environment, the present embodiment does not know its own connection information maintenance timer information. The present invention relates to a case of reconnecting to a second base station different from the first base station which has been connected to the first base station. In this case, similarly to the fifth embodiment, access information may or may not remain valid in the first base station. Accordingly, the mobile station sends a predetermined message (eg, RNG-REQ) to the second base station to inquire whether the access information stored in the first base station is valid or whether to perform an optimization procedure for network reconnection by the second base station. Then, proceed with the reconnection procedure according to the response message.

9A and 9B sequentially illustrate the reconnection procedure according to the sixth embodiment. In particular, FIG. 9A illustrates a case of notifying whether the RNG-REQ message is valid through an RNG-RSP message, and FIG. 9B illustrates whether the RNG-REQ message is valid as a predetermined time without a response message. The case is shown.

Since steps S901 to S905 are the same as the above-described steps S801 to S805, description thereof will be omitted.

When the power of the mobile terminal is turned on or the link condition is improved, the procedure for reconnection is started while performing channel search with the second base station again (S906).

The mobile station receives the DL-MAP and UL-MAP messages from the second base station, and receives configuration change count values of DCD and UCD of the second base station previously stored before disconnection and from the second base station. Compares the DL-MAP, UL-MAP DCD count and UCD count. If both are the same, since the pre-stored DCD and UCD information is valid, the base station including the pre-stored DCD and UCD information is used without waiting for a new DCD and UCD message from the second base station (S907). However, if the DCD, UCD information stored in the mobile terminal is not valid, the DCD, UCD message is transmitted again from the second base station.

However, since the mobile terminal cannot know its access information maintenance timer information due to an unexpected disconnection, the mobile terminal inquires whether to store valid access information or the network re-entry optimization accordingly. Send a message requesting a procedure. The RNG-REQ message can be used as such a message. In this case, it is preferable that the message includes a message authorization code for authenticating the validity of the mobile terminal. Since the following procedure is the same as the above-described procedure of S809, a description thereof will be omitted.

Next, a method of synchronizing between the access information maintenance timer of the mobile terminal and the access information maintenance timer of the base station will be described.

FIG. 10 conceptually illustrates an error of a connection information maintenance timer that may occur between a mobile terminal and a base station.

Unlike the handoff situation in which the mobile terminal explicitly informs the access information maintenance timer time through the MOB_HO-IND message, it is difficult to synchronize the access information maintenance timer time between the terminal and the base station in the reconnection situation. In other words, an error as shown in FIG. 10 is detected between the time when the mobile terminal starts the access information maintenance timer due to disconnection from the base station and the time when the base station starts the access information maintenance timer by detecting an abnormality as a result of monitoring the signal flow of the mobile terminal. Since (T _{Retain _ Time _ Gap} ) may occur, the error should be taken into account when examining the value of the connection information maintenance timer to determine whether the mobile terminal performs the network reconnection procedure.

A method of synchronizing between the connection information maintenance timers of both the first method according to when the base station informs the mobile terminal of its timer time, the first method to inform the base station before disconnection and the second to inform after starting the reconnection Can be divided into ways. Here, the first method may be commonly applied to the first, second, fourth, and fifth embodiments, and the second method may be applied to the third and sixth embodiments.

11 is a signal flowchart sequentially illustrating an embodiment of a synchronization process according to the first method.

The first method may be classified into three types according to the type of message used to inform the timer time.

The first method is a method in which the base station synchronizes the access information maintenance timer of the mobile station and the base station using the RES-CMD message as shown in [Method 1] of FIG. 11. The base station transmits an RES-CMD message to instruct initialization of the mobile terminal and reconnection with the base station when a repetitive error occurs in the information sent by the mobile terminal for a predetermined time or there is no response from the mobile terminal.

At this time, the base station starts its own connection information maintenance timer at the time when the RES-CMD message is transmitted, and the mobile station starts its own connection information maintenance timer in consideration of the message transmission time from the base station to the terminal. The connection information maintenance timer can be synchronized with each other. When reconnecting, the mobile terminal may perform reconnection by selecting an appropriate method according to a situation from among the reconnection methods described above in consideration of the access information maintenance timer.

The second method is a case in which the base station instructs the mobile station to reconnect to another base station through a DREG-CMD message as shown in [Method 2] of FIG. 11. When the base station includes a plurality of mobile terminals to the extent that the base station deviates from its capability range, the base station may instruct a specific terminal to release the connection. When the base station transmits the action code of the DREG-CMD message to 0x00 to a specific mobile terminal, the terminal receiving the message disconnects from the current base station and searches for a channel of another accessible base station to attempt access. do. At this point, the base station starts the terminal information maintenance timer at the time when the base station transmits the DREG-CMD, and the terminal starts the access information maintenance timer in consideration of the message transmission time from the base station to the terminal to synchronize the terminal information maintenance timer of the base station with the terminal. Can be adjusted.

The third method is a power down indicator of the RNG-REQ message when the mobile terminal is disconnected from the base station due to the user's power shutdown or low battery, as shown in [Method 3] of FIG. 11. By transmitting the parameter value of 1 as 1, it informs that the connection with the base station is released. The base station receiving the message starts the terminal information maintenance timer and transmits the RNG-RSP message including the terminal information maintenance timer information and the status code to synchronize the terminal information maintenance timer between the terminal and the base station.

In the RES-CMD message, the DREG-CMD message, and the RNG-RSP message, a connection information retention indicator (Resource Retain Indicator = 0 or 1) and / or a start time of a timer for designating whether to maintain the connection information at the base station is specified. The connection information maintenance start time may be included. Here, the access information holding start time may specify an absolute value of a start frame number or a relative value such as offset information of the start time.

12 is a signal flowchart sequentially showing an embodiment of a synchronization process according to the second method.

According to the present embodiment, when the mobile terminal cannot perform the normal connection termination procedure such as disconnection due to sudden power off or the like, and thus does not know its own access information maintenance timer information, the base station may not be able to access the mobile terminal after the network reconnection starts. It's about how to tell your timer time.

The present embodiment further includes the step of transmitting an RNG-REQ message including its own identification information to the base station and receiving an RNG-RSP message including predetermined synchronization information from the base station in response to the above-described embodiment 3; Everything is the same except for the point.

That is, before transmitting the second RNG-REQ message including the message authentication code to the base station, the mobile terminal transmits the first RNG-REQ message including its MAC address to the base station for the first access with the base station. Whether the base station maintains the access information of the terminal by receiving a first RNG-RSP message including the terminal information status indicator (Resource_Retain_Status = 0 or 1) according to whether there is currently access information of the mobile station from the terminal. Figure out.

13 is a signal flowchart sequentially illustrating another embodiment of a synchronization process according to the second method.

In this embodiment, as shown in FIG. 12, when the mobile terminal cannot perform a normal connection termination procedure such as disconnection due to a sudden power off or the like, and does not know its own connection information maintenance timer information, the first base station which has previously connected The present invention relates to a method in which a second base station informs a mobile terminal of its timer time after initiating reconnection to another second base station.

This embodiment transmits an RNG-REQ message including its own identification information and the identification information of the first base station to the second base station in comparison with the above-described embodiment 6 and includes an RNG including predetermined synchronization information from the second base station in response thereto. All are the same except that it further comprises the step of receiving an RSP message.

That is, the mobile terminal prior to transmitting the second RNG-REQ message including the message authentication code to the second base station, the first RNG including its MAC address and the ID of the first base station for the first access with the second base station. The base station by transmitting a -REQ message to the second base station and receiving a first RNG-RSP message including a terminal information status indicator (Resource_Retain_Status = 0 or 1) according to whether the access information of the mobile station currently exists from the base station; It is grasped whether or not connection information of this terminal is maintained.

Mobile terminal supporting fast network reconnection

Hereinafter, a configuration of a mobile terminal supporting the aforementioned network reconnection method will be described. 14 is a block diagram showing the configuration of a mobile terminal of the present invention.

The mobile terminal includes an input unit 110 for selecting a desired function or receiving information, a display unit 120 for displaying various information for operating the mobile terminal, various programs and a receiving side for operating the mobile terminal. A memory unit 130 storing data to be transmitted to the wireless communication unit, a wireless communication unit 140 for receiving an external signal and transmitting data to the receiving side, and converting and amplifying a digital voice signal into an analog voice signal to a speaker SP. A voice processing unit 150 for outputting or amplifying a voice signal from a microphone MIC and converting the voice signal into a digital signal, and a controller 160 and a timer 170 for controlling the overall driving of the mobile terminal.

The memory unit 130 stores predetermined connection information acquired in the initial network connection process and makes it available again when reconnecting. In particular, in order to securely retain the access information even when the network connection is released for an unexpected reason, the memory unit 130 may be formed of a nonvolatile storage medium.

Information stored in the nonvolatile storage medium of the memory 130 may be classified into two types. First, information about a currently connected base station and neighbor base stations including a base station including DCD and UCD information. Second, information about a current connection between a base station and a terminal generated through message transfer between the base station and the terminal when the terminal accesses the base station. This information includes 1) Basic Capability Information, 2) Authentication Keys and Message Authorization Keys, and 3) Operation Parameters.

The timer 170 is a first timer (connection information maintenance timer, drawing) to start an operation from the time of disconnection to maintain the connection information stored in the memory unit 130 for a predetermined time when the connection is released from the current network. (Not shown), and the mobile station makes an optimization request for re-entry to the base station, but without the response from the base station, the base station does not have valid access information or the optimization request to determine that the optimization request has failed authentication. And it may further include a second timer (Tx timer, not shown in the figure) to start the operation at the same time.

When the connection of the current network is released, the controller 160 reconnects to the same base station or a new base station using the access information stored in the memory unit 130. Specific functions of the controller 160 are the same as those described in detail in the first to sixth embodiments, and a description thereof will be omitted.

In addition, when the synchronization information regarding the first timer is received from the base station before or after the connection with the current network is released or after the connection is released, the controller 160 synchronizes the timer with the base station according to the corresponding synchronization information. Detailed functions of the control unit 160 in this regard are also the same as those described in the description of FIGS. 11 to 13, and thus description thereof will be omitted.

On the other hand, the mobile terminal of the present invention PDA (Personal Digital Assistant), cellular phone, PCS (Personal Communication Service) phone, GSM (Global System for Mobile) phone, WCDMA (Wideband CDMA) phone, MBS (Mobile Broadband System) phone And the like can be used.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the technical spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited by these.

According to the present invention, the procedure required for reconnection can be omitted as much as possible by reusing connection information during initial network connection, thereby ensuring continuity of network connection and preventing unnecessary waste of communication resources.

Claims (25)

Storing, by the mobile terminal, predetermined access information acquired in an initial network access process in a nonvolatile storage area; And Performing reconnection by using the stored connection information when reconnection is initiated to the same network before a preset time from when the initial connection is released. Network reconnection method in a broadband wireless access system comprising a. The method of claim 1, When reconnection starts after a preset time from when the initial connection is released, Transmitting a message requesting reconnection optimization to the base station; And And performing a necessary access procedure according to the reconnection optimization decision result of the base station. The method of claim 2, wherein the reconnection optimization The network reconnection method in a broadband wireless access system performed when the request message is authenticated as being legitimate and the access information of the mobile terminal is stored in the base station. The method of claim 3, At least one of when the authentication of the request message fails and when the access information of the mobile terminal is not stored in the base station, Receiving a response message denying the request; And And performing the initial network access procedure again. The method of claim 3, At least one of when the authentication of the request message fails and when the access information of the mobile terminal is not stored in the base station, If the response message is not received within a predetermined time from the transmission of the request message, performing the initial network access procedure again. The method of claim 1, When the mobile terminal starts to reconnect in the state of losing time information from the initial disconnection, Transmitting a message requesting reconnection optimization to the base station; And And performing a necessary access procedure according to the reconnection optimization decision result of the base station. 7. The method of claim 6, wherein the reconnection optimization The network reconnection method in a broadband wireless access system performed when the request message is authenticated as being legitimate and the access information of the mobile terminal is stored in the base station. The method of claim 7, wherein At least one of when the authentication of the request message fails and when the access information of the mobile terminal is not stored in the base station, Receiving a response message denying the request; And And performing the initial network access procedure again. The method of claim 7, wherein At least one of when the authentication of the request message fails and when the access information of the mobile terminal is not stored in the base station, If the response message is not received within a predetermined time from the transmission of the request message, performing the initial network access procedure again. The method according to any one of claims 1 to 9, Receiving synchronization information between the elapsed time after disconnection measured by the base station and the elapsed time after disconnection measured by the mobile terminal, before the connection with the base station is released. . The method according to any one of claims 1 to 9, Requesting synchronization information between the elapsed time after disconnection measured by the base station and the elapsed time after disconnection measured by the mobile terminal, after the connection with the base station is released. . Storing, by the mobile terminal, predetermined access information acquired in an initial access procedure to the first base station in a nonvolatile storage area; Performing a reconnection by using the stored access information when the initial access is released and a reconnection is started to a second base station. Network reconnection method in a broadband wireless access system comprising a. The method of claim 12, wherein the reconnecting step is Transmitting a message requesting reconnection optimization to a second base station; And performing, by the second base station, a necessary access procedure according to the reconnection optimization decision result obtained by using the access information received from the first base station. The method of claim 13, wherein the reconnection optimization The network reconnection method in a broadband wireless access system performed when the request message is authenticated as being legitimate and the access information of the mobile terminal is stored in a second base station. The method of claim 14, At least one of when the authentication of the request message fails and when the access information of the mobile terminal is not stored in the second base station, Receiving a response message denying the request; And And performing all of the initial access procedure for the second base station. The method of claim 14, At least one of when the authentication of the request message fails and when the access information of the mobile terminal is not stored in the second base station, And performing a complete initial access procedure for a second base station if a response message is not received within a predetermined time from the transmission of the request message. The method of claim 12, When reconnection starts after a preset time from when the initial connection is released, And performing all of the initial access procedure for the second base station. The method according to any one of claims 12 to 17, And before the connection with the first base station is released, receiving synchronization information between the elapsed time after disconnection measured by the first base station and the elapsed time after disconnection measured by the mobile terminal from the second base station. Network reconnection method in system. The method according to any one of claims 12 to 17, After the connection with the first base station is released, requesting, by the second base station, synchronization information between the elapsed time after disconnection measured by the base station and the elapsed time after disconnection measured by the mobile terminal; And And receiving, by the second base station, the synchronization information received from the first base station from the second base station. A nonvolatile memory for storing predetermined connection information obtained during an initial network connection process; A timer for measuring elapsed time from when the initial connection was released; And Control unit for performing the reconnection by using the connection information stored in the memory when the reconnection is started to the network before the timer expires A mobile terminal performing network reconnection in a broadband wireless access system comprising a. The method of claim 20, wherein the control unit If reconnection is started after the timer expires, A mobile terminal for performing network reconnection in a broadband wireless access system further comprising a function of transmitting a message for requesting reconnection optimization to a base station and performing a necessary access procedure according to the reconnection optimization determination result of the base station. The method of claim 21, wherein the reconnection optimization And performing the network reconnection in the broadband wireless access system performed when the request message is authenticated as being legitimate and the access information of the mobile terminal is stored in the base station. The method of claim 22, wherein the control unit At least one of when the authentication of the request message fails and when the access information of the mobile terminal is not stored in the base station, The mobile terminal performing network reconnection in the broadband wireless access system further comprising the function of performing the initial network access procedure again when a response message rejecting the request is received. The method of claim 22, wherein the control unit At least one of when the authentication of the request message fails and when the access information of the mobile terminal is not stored in the base station, And performing a network reconnection in a broadband wireless access system, the function of performing the initial network access procedure again if a response message is not received within a predetermined time from the transmission of the request message. The method of claim 20, When reconnection is started while the timer information is lost, The control unit transmits a message for requesting reconnection optimization to the base station, and performs a network reconnection in the broadband wireless access system further comprising the function of performing the necessary connection procedure according to the reconnection optimization determination result of the base station.

Images