JP5221814B2 - How to perform uncontrolled handover - Google Patents

Description

  The present invention relates to an efficient and reliable handover method and apparatus applicable to various wireless connection systems.

  Hereinafter, the handover and ranging procedure will be briefly described.

  Handover (HO) means that when a moving terminal moves in a communication area (zone) such as a cell of a base station, it moves out of the cell area of the serving base station with which it is talking. This means a function for continuing a call (such as a function for exchanging a channel or a line and maintaining a call in progress) when entering the cell area of the base station.

  A handover can be classified into a soft handover, a soft handover, and a hard handover.

  Here, the softer handover is a handover performed within one cell, and means that a terminal switches a channel used to a good channel or the like within a cell coverage. Soft handover refers to a method in which two adjacent channels are used simultaneously, and finally one channel is gradually cut. In the case of soft handover, the same frequency band is used in the CDMA system, which is easy to implement. Hard handover refers to a method of disconnecting a currently talking channel and immediately connecting to another channel.

  The terminal moves from the cell area of the currently serving base station to the cell area of another base station, and can perform a ranging procedure for performing handover to the other base station.

  Ranging refers to a collection of processes for maintaining connection quality (especially synchronization) of RF (Radio Frequency) communication between a base station and a terminal in IEEE 802.16 or the mobile Internet. When ranging is a multiple connection based on OFDMA (Orthogonal Frequency Division Multiple Access) / TDD (Time Division Duplexing), there is no problem because the base station transmits to a large number of terminals at one reference timing in the downlink.

  However, in the uplink, since a large number of terminals each transmit a signal, the propagation delay may vary from terminal to terminal. For this reason, the base station and the terminal perform ranging using a separate timing synchronization method. That is, ranging is a procedure for accurately adjusting synchronization with respect to transmission time by a large number of terminals.

  There are Initial Ranging, Periodic Ranging, and Hand-over Ranging for uplink synchronization acquisition and power control between the terminal and the base station. In addition, there is bandwidth request ranging (Bandwidth Request (BR) Ranging) for a terminal to request a bandwidth from a base station.

  Initial ranging is used for initial network entry and connection procedures when a terminal first enters a base station (eg, when the terminal is powered on or switched from a long sleep mode to an idle mode). Periodic ranging is periodically transmitted by the terminal to the base station for synchronization tracking. Handover ranging is performed by the terminal for synchronization with the target base station while the terminal performs handover. Bandwidth request ranging is used to request an uplink allocation from a base station. Bandwidth request ranging is performed by the terminal after synchronization with the system is established.

  When the base station receives the ranging request message from the terminal, the base station generates a connection identifier (CID: Connection IDentifier) of the corresponding terminal. Thereafter, the base station performs renegotiation, re-authentication and re-registration processes with the terminal.

  The connection identifier (CID) is an address for identifying a connection (connection) mapped to a service flow (Service Flow) required between peers on a medium access control (MAC) sublayer. Say. The CID is included in a MAC PDU (MAC Protocol Data Unit) header. That is, any connection between a base station and a terminal is identified by a CID included in the MAC header, and the CID is associated with an SFID (Service Flow IDentifier) that defines a service flow QoS parameter associated therewith.

  The management CID can be received from the base station at the time of initialization when all terminals connect to the base station. That is, the management CID may be allocated from the base station to the terminal through a series of ranging and registration processes. The management CID can be classified into a basic CID (Basic CID, BCID), a main CID (Primary CID, PCID), and a secondary CID (Secondary CID, SCID).

  Here, the basic CID (BCID) is used by the base station to identify the terminal in the initial connection stage. That is, the MAC address of the terminal is mapped to the basic CID. The primary CID (PCID) may be used in authentication messages and dynamic resource allocation related messages. Further, the sub CID (BCID) is optional, and whether or not it is used may be determined in the terminal capability negotiation process.

  In addition to the management CID, there are a transfer CID (Transport CID, TCID) for distinguishing service of user traffic, a broadcast CID (Broadcasting CID) and a multicast CID (Multicasting CID) for distinguishing broadcast traffic. Here, the transfer CID (TCID) may be assigned for each connection established between the terminal and the base station.

  In the handover technique, when a mobile terminal moves from a serving base station to another target base station, a data context (data context) that the mobile terminal is currently communicating with the serving base station is reduced to a minimum interruption time ( It means moving to a target base station with interruption time) and maintaining communication. That is, it is a technique for ensuring service continuity of mobile terminals.

  However, when a mobile terminal performs an uncontrolled handover instead of a general handover procedure, a clear procedure has not been developed. In addition, in order to perform the ranging procedure at the time of non-control handover, the medium access control address for identifying the mobile terminal must be transferred to the target base station. In this case, it may be difficult to ensure the location confidentiality of the mobile terminal.

  That is, a procedure for ensuring the location privacy of the mobile terminal needs to be considered in order to block malicious security threats to the mobile terminal during non-controlled handover.

  In order to provide location confidentiality of the mobile terminal, the use of the mobile terminal's hashed MAC address and temporary station identifier can be considered. However, in this case, it is necessary to assign the hashed MAC address and / or temporary station identifier of the mobile terminal in the ranging process, and the ranging procedure may become extra long.

  The present invention has been devised to solve the above problems, and an object of the present invention is to provide a method and apparatus for performing an efficient and reliable handover.

  Another object of the present invention is to provide a method for supporting location confidentiality of a mobile terminal when the mobile terminal performs an uncontrolled handover.

  Still another object of the present invention is to efficiently receive an identifier (STID: Station Identifier) of a mobile terminal used in a handover target base station when performing a non-controlled handover from a serving base station to another base station. Is to provide.

  The technical problem to be achieved by the present invention is not limited to the above technical problem, and other technical problems that are not mentioned can be derived from the embodiments of the present invention described below, based on the technique to which the present invention belongs. It will be clearly derived and understood by those with ordinary knowledge in the field.

  In order to solve the above technical problem, the present invention provides various systems, methods, and apparatuses for performing an efficient and reliable handover applicable to various wireless connection systems.

  In an embodiment of the present invention, uncontrolled handover is performed when the candidate base station recommended by the serving base station does not include the first target base station desired by the mobile terminal, or with the candidate base station and the handover ranging procedure. Can be performed when the mobile terminal cannot reach the candidate base station.

  As a first embodiment of the present invention, a method of performing an uncontrolled handover (Uncontrolled HO) includes a serving base station identifier (BSID = BSID =) for a mobile terminal to enter or re-enter the network at a first target base station. 3) and a ranging request (AAI_RNG-REQ) message including the first identifier (STID) used in the serving base station, the security target information valid from the first target base station, Receiving a ranging response message including a second identifier for identifying the mobile terminal.

  The first embodiment may further include the step of the mobile terminal receiving a handover command (AAI_HO-CMD) message including handover related information and information on candidate base stations from the serving base station. Here, the handover related information includes one or more of an operation time (Action Time) parameter indicating a start point of performing the network (re) entry procedure, a dedicated handover ranging code used in the candidate base station, and a ranging opportunity. be able to.

  In the first embodiment, when the mobile terminal performs a non-controlled handover, the mobile terminal uses the event code (Code 2) indicating the non-controlled handover and the identifier of the first target base station desired by the mobile terminal (BSID = The method may further include forwarding a handover indication (AAI_HO-IND) message including 5) to the serving base station.

  At this time, the first identifier is a station identifier (STID) that uniquely identifies the mobile terminal at the serving base station, and the second identifier is a station identifier that uniquely identifies the mobile terminal at the first target base station, or mobile It may be any temporary station identifier (T-STID) used to protect the location confidentiality of the terminal.

  In the first embodiment, a mobile terminal transfers a ranging code for performing a network (re) entry procedure to a first target base station, and an allocation related to a resource area for performing the ranging procedure as a response to the ranging code. Receiving a ranging response message that includes the information. Here, the ranging request message may be transferred through the resource area represented by the allocation information.

Valid security-related information may include a Cipher-based message authentication code (CMAC) tuple.
As a second embodiment of the present invention, a system, apparatus, and method for performing uncontrolled handover (Uncontrolled HO) are used in a serving base station identifier and serving base station in a network (re) entry procedure with a mobile terminal. Receiving a ranging request message including the first identifier from the mobile terminal, and transferring a ranging response message including the security-related information valid at the target base station and the second identifier for identifying the mobile terminal to the mobile terminal. And can be included.

  Here, the first identifier is a station identifier (STID) that uniquely identifies the mobile terminal at the serving base station, and the second identifier is a station identifier that uniquely identifies the mobile terminal at the first target base station, or mobile It may be any temporary station identifier (T-STID) used to protect the location confidentiality of the terminal.

  Valid security related information may include CMAC tuples.

  In the second embodiment, the first target base station receives a ranging code for performing the network (re) entry procedure from the mobile terminal, and the allocation of the resource region for performing the ranging procedure as a response to the ranging code. Forwarding a ranging response message including the information to the mobile terminal. Here, the ranging request message may be received through the resource area represented by the allocation information.

  In the second embodiment, the first target base station transmits a request message for requesting information on the mobile terminal to the serving base station indicated by the serving base station identifier (BSID = 3), and the mobile base station moves from the serving base station. Receiving a response message including information about the terminal. At this time, the information regarding the mobile terminal may include a medium access control address of the mobile terminal.

  As a third embodiment of the present invention, a mobile terminal that performs uncontrolled handover (Uncontrolled HO) includes a transmission module that controls transmission of a message used for non-controlled handover, and reception of a message used for non-controlled handover. A receiving module for controlling the data, a memory for storing parameters and information elements used for uncontrolled handover, and a processor for controlling uncontrolled handover operations.

  Here, the processor sends a ranging request message including the identifier of the serving base station and the first identifier used by the serving base station to transmit the network (re-entry) at the first target base station via the transmission module. Control the uncontrolled handover operation by receiving the ranging response message including the valid security-related information and the second identifier for identifying the mobile terminal from the first target base station via the receiving module. can do.

  The receiving module may receive a handover command (AAI_HO-CMD) message including handover related information and information on candidate base stations from a serving base station and transmit the received handover command (AAI_HO-CMD) message to a processor. The processor can store handover related information included in the handover command message in a memory and perform an uncontrolled handover procedure accordingly.

  Here, the handover related information may include one or more of an operation time parameter indicating a start time of performing a network (re) entry procedure, a handover ranging code used in a candidate base station, and a ranging opportunity.

  When the mobile terminal of the third embodiment performs an uncontrolled handover, the processor of the mobile terminal includes an event code (Code 2) indicating the uncontrolled handover and an identifier of the first target base station desired by the mobile terminal The handover instruction message can be forwarded to the serving base station via the transmission module.

  Here, the first identifier is a station identifier (STID) that uniquely identifies the mobile terminal at the serving base station, and the second identifier is a station identifier that uniquely identifies the mobile terminal at the first target base station, or mobile It may be any temporary station identifier used to protect the location confidentiality of the terminal.

  Valid security related information may include CMAC tuples.

  The processor of the mobile terminal transfers the ranging code for performing the network (re) entry procedure to the first target base station via the transmission module, and performs the ranging procedure as a response to the ranging code via the reception module. Receiving a ranging response message including allocation information related to the resource area for controlling uncontrolled handover. At this time, the processor can control the transmission module to transfer the ranging request message through the resource area represented by the allocation information.

  According to the embodiment of the present invention, the following effects can be obtained.

  First, the user can perform an efficient and reliable handover by using the embodiment of the present invention.

  Second, when the mobile terminal performs an uncontrolled handover, the location privacy of the mobile terminal can be supported.

  Third, when the mobile terminal performs an uncontrolled handover, the mobile terminal identifier (STID) used in the handover target base station can be efficiently allocated.

  The effects obtained from the examples of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be derived from the following description of the examples of the present invention in the technical field to which the present invention belongs. It will be clearly derived and understood by those with ordinary knowledge.

3 is a flowchart illustrating a general handover procedure performed in an IEEE 802.16e system. FIG. 2 is a diagram illustrating a general procedure for handover performed in an IEEE 802.16m system. It is a figure which shows the case where a mobile terminal performs non-control handover to a neighboring base station desired by itself. It is a figure which shows the method of performing a non-control handover to a neighboring base station when the mobile terminal fails in the handover to the handover target base station. FIG. 6 is a diagram illustrating a method for performing an uncontrolled handover to a neighboring base station when a handover to a handover target base station fails according to an embodiment of the present invention. FIG. 10 is a diagram illustrating an example of a method for performing uncontrolled handover to a neighboring base station when handover to a handover target base station fails in another embodiment of the present invention. FIG. 10 is a diagram illustrating another example of a method for performing an uncontrolled handover to a neighboring base station when handover to a handover target base station fails in another embodiment of the present invention. FIG. 10 is a diagram showing still another example of a method for performing an uncontrolled handover to a neighboring base station when a handover to a handover target base station fails in another embodiment of the present invention. FIG. 9 is a diagram illustrating a mobile terminal and a base station that are still another embodiment of the present invention and that can execute each embodiment of the present invention described in FIGS. 2 to 8.

  The embodiments of the present invention disclose various methods and apparatuses for performing an efficient and reliable handover applicable to various wireless access systems.

  The following embodiment is a combination of the components and features of the present invention in a predetermined form. Each component or feature may be considered optional unless otherwise explicitly stated. Each component or feature may be implemented in a form that is not combined with other components or features. In addition, some embodiments and / or features may be combined to form an embodiment of the present invention. The order of operations described in the embodiments of the present invention can be changed. Some configurations or features of one embodiment may be included in other embodiments and may replace corresponding configurations or features of other embodiments.

  In the description of the drawings, procedures or steps that obscure the gist of the present invention are not described, and descriptions of procedures or steps that can be understood by those skilled in the art are omitted.

  In the present specification, the embodiments of the present invention have been described centering on the data transmission / reception relationship between the base station and the mobile station. Here, the base station has the meaning of a terminal node (terminal node) of the network that communicates directly with the mobile station. In this document, the specific operation that is performed by the base station may be performed by an upper node of the base station in some cases.

  That is, various operations performed for communication with a mobile station in a network including a large number of network nodes including a base station can be performed in the base station or another network node other than the base station. Here, the “base station” can be replaced with a term such as a fixed station, a Node B, an eNode B (eNB), an advanced base station (Advanced Base Station), or an access point (Access Point). .

  In addition, a “mobile station (MS)” includes a UE (User Equipment), an SS (Subscriber Station), an MSS (Mobile Subscriber Station), a mobile terminal (Mobile Terminal), an advanced mobile terminal (AMS) ) Or terminal (Terminal).

  The transmitting end means a fixed and / or mobile node that provides a data service or a voice service, and the receiving end means a fixed and / or mobile node that receives a data service or a voice service. Therefore, in the uplink, the mobile station may be the transmitting end and the base station may be the receiving end. Similarly, in the downlink, the mobile station may be the receiving end and the base station may be the transmitting end.

  Embodiments of the present invention may be supported by standard documents disclosed in at least one of the IEEE 802 system, the 3GPP system, the 3GPP LTE system, and the 3GPP2 system which are wireless connection systems. In other words, in the embodiment of the present invention, a stage or a part that is not described for clarifying the technical idea may be supported by the above document.

  In addition, all the terms disclosed in this document can be explained by the above standard documents. In particular, embodiments of the present invention may be supported by one or more of the IEEE 802.16 system standard documents P802.16e-2004, P802.16e-2005 and P802.16 Rev2 and P802.16m standard documents. .

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The detailed description disclosed below in connection with the appended drawings is intended as a description of exemplary embodiments of the invention and is not intended to represent the only embodiments in which the invention may be practiced.

  In addition, specific terms used in the embodiments of the present invention are provided to assist the understanding of the present invention, and the use of such specific terms is not limited to the scope of the technical idea of the present invention. The form can be changed.

  For example, in an embodiment of the present invention, uncontrolled handover is also referred to as uncoordinated handover or uncoordinated handover.

  FIG. 1 is a diagram illustrating a general handover procedure performed in an IEEE 802.16e system.

  Referring to FIG. 1, a mobile terminal selects a cell during handover and initial network entry (S101, S102). The cell selection is a procedure in which a mobile terminal performs scanning or ranging with one or more base stations in order to search for an appropriate base station for network connection or handover. The mobile terminal must schedule a scan interval or a sleep interval to determine the initial network entry to the base station or the possibility of handover to the target base station.

  When the mobile terminal enters the initial network, it acquires synchronization and downlink parameters with the serving base station (S103). A service base station refers to a base station that provides a service in a network to which a mobile terminal is currently entering, and is also called a serving base station. The mobile terminal that has acquired synchronization with the serving base station obtains an uplink parameter to the serving base station (S104), and adjusts the uplink parameter while performing a ranging procedure with the serving base station (S105). Through the above procedure, the mobile terminal and the serving base station form a basic function for communication (S106). The serving base station authorizes the mobile terminal and exchanges a key for encryption (S107). Thus, the mobile terminal is registered with the serving base station (S108), and IP connection is set up (S109).

  The service base station transfers the operation parameters to the mobile terminal so that the mobile terminal performs a communication procedure (S110), the connection between the mobile terminal and the service base station is established (S111), and the mobile terminal and the base station Can perform a normal operation (S112). The mobile terminal continues to search for an adjacent base station even during normal operation at the serving base station (S113).

  The reason for performing S113 is that as the mobile terminal moves away from the service base station while moving, the quality of service provided from the service base station becomes weaker, and therefore, a base station that can provide better service is searched. . Therefore, an adjacent base station that provides a better service than the serving base station is called a target base station, and the mobile terminal can search for the target base station and perform handover.

  In general, handover occurs when a mobile terminal moves from a serving base station to a cell area of a target base station. Handover refers to a mobile terminal switching a radio interface, a service flow, a network access point, and the like from a service base station to a target base station, and starts when the mobile terminal, the service base station, or a network administrator determines a handover. (S114).

  The mobile terminal selects a target base station (S115), acquires synchronization with the target base station, and acquires downlink parameters (S116). The mobile terminal acquires the uplink parameters of the target base station (S117), and adjusts the ranging and uplink parameters with the target base station (S118). At this time, if the mobile terminal receives an NBR-ADV message including the target base station identifier, frequency, and uplink / downlink channel descriptor (UCD / DCD) in advance, the scanning process and the synchronization procedure can be simplified. . If the target base station receives a handover report from the serving base station through the backbone network, an initial contention opportunity in a non-contention scheme can be provided in an uplink map (UL-MAP) message.

  Through the above procedure, the mobile terminal and the target base station form a basic function (S119), the mobile terminal and the target base station perform ranging, and start a network re-entry procedure. Also, the mobile terminal performs re-registration and reconnection to the target base station (S120). Thus, the mobile terminal is registered in the target base station (S121), and the IP connection of the target base station is also reset in the mobile terminal (S122). Thus, the target base station becomes a service base station and can provide a service to the terminal.

  Referring again to the case of performing handover in FIG. 1, the mobile terminal selects a cell based on information on neighboring base stations obtained from scanning and decides to perform handover from the serving base station to the target base station. Can do. When the handover is determined, the mobile terminal performs synchronization with the target base station and performs a ranging procedure. Thereafter, reauthorization for the mobile terminal is performed, and at this time, the target base station can request information on the mobile terminal from the serving base station through a backbone message.

  Handover and network reentry procedures may be greatly reduced due to information about the mobile terminal held by the target base station. Also, some network entry procedures may be omitted depending on the amount of information about the terminal held by the target base station.

  Although FIG. 1 mainly describes the case where handover is started by the mobile terminal, the serving base station may determine the handover of the mobile terminal in consideration of the communication environment with the mobile terminal. When the handover is determined by the serving base station, a procedure similar to that shown in FIG. 1 may be performed.

General of IEEE 802.16m handover

  FIG. 2 is a diagram illustrating a general process of a handover performed in the IEEE 802.16m system.

  In the IEEE 802.16m system, handover is mainly performed by (1) handover determination and initiation (HO decision and initiation), (2) handover preparation (HO preparation), and (3) handover execution (HO). (Execution) can be included.

  Before performing these three procedures, a mobile terminal (AMS: Advanced Mobile Station) needs to perform a scanning procedure for collecting information on neighboring base stations. Such a scanning procedure is similar to the scanning process in an IEEE 802.16e network. For example, in the IEEE 802.16m system, when there is a section in which the mobile terminal does not communicate with a serving base station (S-ABS), the neighboring base stations may be scanned using this section.

  In the handover decision and start procedure, the mobile terminal or base station can start HO. In the IEEE 802.16m system, the conditions for the mobile terminal to start HO are defined as follows.

1. 1. Conditions for the mobile terminal to define the scanning measurement report time to the serving base station 2. Conditions under which a mobile terminal initiates a handover by transferring an AAI_HO-REQ message Conditions in which a mobile terminal cannot maintain communication with a serving base station

  At this time, when the mobile terminal is handed over to the target base station according to the determination of the serving base station, it is determined whether to perform entry before interruption (EBB: Entry Before Break) or interruption before entry (BBE: Break Before Entry). Is done.

  In FIG. 2, part (A) shows the case where the serving base station starts handover, and part (B) shows the case where the mobile terminal starts handover.

  Referring to part (A) of FIG. 2, the serving base station (S-ABS) has a condition for one or more target base stations and a future handover execution (HO execution) procedure in order to perform cooperative handover. , And resources allocated to the mobile terminal can be negotiated.

  The serving base station may transmit information on the mobile terminal (AMS information) to one or more target base stations through a handover request (HO-REQ) message (S210).

  Each of the one or more target base stations provides handover-related information including at least one of a dedicated ranging code and a ranging opportunity that can be used by the mobile terminal in the target base station. Can be transmitted through a handover response (HO-RSP) message. At this time, the handover response message may further include one or more of a terminal identifier (STID: Station ID) and a security context (for example, nonce) used in the target base station (S212). .

  The serving base station uses the handover command (AAI_HO-CMD) message to transmit handover related information regarding one or more handover candidate base stations determined to be the handover target base station (that is, the target base station) to the mobile terminal. (S214).

  In step S214, the handover command message may further include an action time parameter and a disconnect time parameter. Here, the operation time parameter represents the time when the mobile terminal performs a network re-entry procedure, and the disconnection time parameter is the uplink and downlink (DL / UL) from the serving base station to the mobile terminal. ) Represents the time to stop resource allocation.

  Referring to FIG. 2B, when the mobile terminal satisfies the handover condition, the mobile terminal can request a handover to the serving base station using a handover request (AAI-HO-REQ) message (S220).

  The serving base station that has received the handover request message from the mobile terminal can transfer a handover request (HO-REQ) message including information on the mobile terminal (AMS information) to one or more target base stations (S222).

  Subsequent steps S224 and S226 are the same as steps S212 and S214, and thus a duplicate description is omitted. It can be said that the steps S210, S212, S214, S220, S222, S224, and S226 correspond to the handover preparation procedure. Through such a handover preparation procedure, the station identifier of the mobile terminal can be updated in advance between the mobile terminal and the target base station, and a security context (eg, nonce) can be transmitted through transmission / reception of security related information. It can be updated in advance. In addition, a dedicated ranging code used by the mobile terminal may be assigned.

  After the above-described handover preparation (HO preparation) procedure, the mobile terminal can selectively transfer a handover instruction (AAI-HO-IND) message to the serving base station (S228).

  Here, the handover instruction message may include an event code (event code) as shown in Table 1 below.

  Referring to Table 1, when a mobile terminal transfers a handover instruction message to a serving base station, the event code as described above can be set and transferred. When the event code is set to “1” (= code 1), this indicates that the mobile terminal has selected one target base station from a large number of candidate base stations. When the event code is set to “2” (= code 2), this indicates that the mobile terminal cannot reach any candidate base station, and the mobile terminal can subsequently perform an uncontrolled handover procedure. When doing so, it is preferable that the mobile terminal includes the newly determined target base station in the handover instruction message for transfer.

  In Table 1, when the event code is set to “3” (= code 3), it indicates that the mobile terminal cannot maintain the connection with the serving base station until the connection release time set by the serving base station expires. . Further, when the event code is set to “4” (= code 4), this indicates that the mobile terminal cancels the handover.

  That is, when the mobile terminal receives a handover command (AAI_HO-CMD) message including handover related information regarding a plurality of candidate base stations from the serving base station, the mobile terminal finally performs HO through the AAI_HO-IND message. Inform about the selection of the target base station.

  If the serving base station transmits to the mobile terminal only one target base station included in the AAI_HO-CMD message, the mobile terminal does not need to inform the selection of the target base station through the HO-IND. Also, when a handover is canceled or a problem occurs while the mobile terminal is performing a handover, information related thereto can be notified to the serving base station through HO-IND. That is, the HO-IND message only needs to be selectively transferred, and is not necessarily transferred.

  The handover execution (HO execution) procedure is performed at the time indicated by the operation time parameter. That is, the mobile terminal can perform a T-ABS and network re-entry procedure at the time indicated by the operation time parameter (S230).

  In step S230, the mobile terminal can perform a network re-entry procedure by transferring a CDMA ranging code or an AAI_RNG-REQ message to the target base station during operation time.

  When the mobile terminal performs EBB, the mobile terminal can perform communication with the S-ABS during a network re-entry procedure in a predetermined operable interval (AI). At this time, the mobile terminal can perform a network re-entry procedure to the T-ABS during an inoperable interval (UAI: Un-Available Interval) (S240).

  When the mobile terminal performs BBE, the AI or UAI is not defined, and the mobile terminal performs the same procedure as the hard handover of the existing IEEE 802.16e network.

  When the network re-entry procedure is completed, the target base station transfers a handover complete (HO-CMPLT) message to the serving base station (S250), and a data path is set up between the mobile terminal and the target base station ( S260).

  The handover execution scheme of FIG. 2 can be called a control handover or a cooperative handover. The messages and parameters described with reference to FIG. 2 can be similarly applied to each embodiment of the present invention described below, and may be changed or modified according to each condition.

Uncontrolled handover (Uncontrolled HO)

  In some cases, the mobile terminal (AMS) performs an uncontrolled or non-cooperative handover while performing a cooperative handover procedure. In this case, the mobile terminal must perform the same ranging process as when entering the initial network with the target base station.

  When a mobile terminal performs uncontrolled handover, that is, non-cooperative handover, there are two main types. The first type (Type 1) includes a desired target base station to be handed over by a mobile terminal to a handover candidate base station provided by a serving base station through a handover command (AAI-HO-CMD) message. This is the case (non-coordinated ABS). The second type (Type 2) is a case where the mobile terminal attempts to re-enter the target base station, but a CDMA ranging code transfer failure or a ranging message transmission / reception failure occurs (unreachable).

  FIG. 3 is a diagram illustrating a case where the mobile terminal performs the first type non-controlled handover to a desired neighboring base station.

  In FIG. 3, the station identifier (STID) assigned to the mobile terminal (AMS) is “2”, the identifier (BSID) of the serving base station is “3”, and among the candidate base stations, the first target base The identifier of the station is “4”, and the identifier of the second target base station to which the mobile terminal is to be handed over is “5”.

  The mobile terminal can transfer a handover request message to the serving base station to start handover (S301).

  Step S301 is performed only when the mobile terminal starts a handover, and need not be performed when the serving base station starts a handover. That is, step S301 may be selectively performed according to a handover situation.

  The serving base station (BSID = 3) can transfer a handover request (AAI_HO-REQ) message including information (AMS INFORMATION) about the mobile terminal to one or more candidate base stations. The information on the mobile terminal may include the medium access control address of the mobile terminal and / or the mobile terminal context (AMS context). However, in this document, for the sake of simplicity, it is assumed that the serving base station transfers a handover request message to a specific first target base station (BSID = 4) (S302).

  The first target base station (BSID = 4) has a dedicated ranging code, a ranging opportunity, an action time parameter, and UAI / AI used when the mobile terminal re-enters the network. A handover response message including handover related information can be transferred to the serving base station through the backbone network. In addition, the handover response message may further include an operation time parameter indicating a network entry time and / or a resource maintenance time parameter indicating a time for maintaining information related to the serving base station (S303).

  The serving base station can include handover related information and recommended candidate base station information in a handover command (AAI_HO-CMD) message and transfer it to the mobile terminal. Here, the information regarding the candidate base station recommended by the serving base station may be a candidate base station identifier (for example, BSID = 4) or a list of candidate base stations (S304).

  However, the candidate base station included in the handover command message may not have a target base station desired by the mobile terminal and may have another target base station desired by the mobile terminal. In that case, the mobile terminal may set the event code to 2 (code 2), and transfer a handover instruction (AAI_HO-IND) message including the desired target base station identifier (BSID = 5) to the serving base station. . Through this process, the mobile terminal can perform an uncontrolled handover with the second target base station (S305).

  However, there is no handover preparation procedure between the second target base station (BSID = 5) desired by the mobile terminal and the serving base station, and the second target base station and the mobile terminal Alternatively, the station identifier of the mobile terminal cannot be updated in advance. For this reason, there is a risk that the location confidentiality of the mobile terminal is exposed.

  Therefore, the mobile terminal and the second target base station use a hashed MAC address or the MAC address of the mobile terminal and a temporary station identifier (temporary STID) to support the location confidentiality of the mobile terminal. A re-entry procedure must be performed. This is because the second target base station and the serving base station cannot coordinate with each other, so that the base station cannot share the security context related to the mobile terminal, and handover optimization (HO optimization) is not performed at all. Because it is a situation.

  The mobile terminal enters the cell area of the second target base station (BSID = 5) desired by itself, and receives a preamble or superframe header (SFH: SuperFrame Header) periodically broadcast from the second target base station. be able to. That is, the mobile terminal can match downlink synchronization (DL synchronization) with the second target base station using a preamble or SFH (S306).

  In order to perform a network re-entry procedure at the second target base station, the mobile terminal transmits a contention-based CDMA ranging code to the second target base station at the earliest ranging opportunity after aligning the downlink synchronization. It can be transferred (S307).

  The second target base station that has received the CDMA ranging code can allocate a resource area for transmitting and receiving a ranging message to the mobile terminal. For this reason, the second target base station can transfer a ranging response (AAI_RNG-RSP) message including information on the assigned radio resource to the mobile terminal (S308).

  The mobile terminal can transfer a ranging request (AAI_RNG-REQ) message to the second target base station through the allocated resource area. At this time, the ranging request message may include a valid CMAC tuple (CMAC Tuple) (S309).

  The second target base station transfers a ranging response (AAI_RNG-RSP) message including the temporary station identifier for the mobile terminal used in the second target base station and the CMAC tuple valid in the second target base station to the mobile terminal. (S310).

  The mobile terminal and the second target base station can perform a performance negotiation procedure using the temporary station identifier (S311), and can update a nonce through an authentication phase (S312).

  Also, the second target base station can assign a station identifier that uniquely identifies the mobile terminal at the second target base station by exchanging management messages with the mobile terminal (S313).

  The mobile terminal that has established a connection with the second target base station can perform reliable data transmission / reception with the second target base station using the station identifier (S314).

  FIG. 4 is a diagram illustrating a method of performing a second type of uncontrolled handover to a neighboring base station when a mobile terminal fails to perform handover to a handover target base station.

  In other words, the mobile terminal (AMS) could not be handed over to the target base station recommended by the base station due to an error that was not intended, but this situation was not notified to the serving base station and other target base stations were not controlled. Shows a case where handover is performed in a conventional manner. Steps S401 to S404 in FIG. 4 are the same as steps S301 to S304 in FIG. 3, and refer to FIG.

  In order to perform handover to the first target base station (BSID = 4) recommended by the serving base station, the mobile terminal can transfer the CDMA ranging code to the first target base station during operation time. However, depending on the channel condition, the mobile terminal may not be able to successfully transfer the CDMA ranging code to the first target base station within the ranging opportunity time (S405).

  Therefore, the mobile terminal can perform an uncontrolled handover (uncontrolled HO) to the second target base station. Hereinafter, steps S406 to S414 for performing uncontrolled handover are the same as steps S306 to S314 of FIG. 3, and refer to FIG.

  3 and 4 have described the uncontrolled handover. The corresponding controlled handover (or cooperative handover) corresponds to the handover method described with reference to FIGS.

  FIG. 5 is a diagram illustrating a method for performing an uncontrolled handover to a neighboring base station when handover to a handover target base station fails, according to an embodiment of the present invention.

  FIG. 5 shows that when a mobile terminal (AMS) performs network re-entry to another target base station in an uncontrolled handover situation, a station identifier (STID) that uniquely identifies the mobile terminal at the target base station is efficiently Disclosed are methods to be assigned. FIG. 5 shows a case where a second type of uncontrolled handover similar to FIG. 4 is performed.

  In FIG. 5, even if the mobile terminal performs a handover, the serving base station may store only the resource maintenance timer without releasing the information on the mobile terminal immediately. This means that if the mobile terminal returns to the serving base station again or information about the mobile terminal is requested from another target base station at the time of uncontrolled handover, the mobile terminal can immediately provide the service again, This is for providing information on the mobile terminal to the base station.

  That is, when the mobile terminal performs an uncontrolled handover to the target base station, when the target base station knows from which serving base station the mobile terminal has moved, the target base station relates to the mobile terminal to the corresponding serving base station. By requesting information, it is possible to efficiently perform the remaining handover procedure or network re-entry procedure while ensuring the location confidentiality of the mobile terminal.

  However, when the resource maintenance timer of the serving base station that provided the service to the mobile terminal expires, the mobile terminal must perform a ranging procedure such as initial network entry with the target base station (AMS is an S-ABS resource maintenance timer). Knows when will expire). That is, the AMS can include the MAC address of the AMS instead of the CMAC tuple (Chiper-based Message Authentication Code Tuple). As an option for the T-ABS to request previous base station information regarding the AMS, the entry request / re-entry request may include an identifier of the S-ABS.

  Steps S501 to S507 in FIG. 5 are the same as steps S401 to S407 in FIG. 4. For the description of the corresponding parts, refer to the descriptions in FIGS.

  The second target base station (BSID = 5) that has received the contention-based CDMA ranging code from the mobile terminal can allocate a resource area for the mobile terminal to perform a network re-entry procedure. Such allocation information regarding the resource area may be included in the CDMA allocation information element (CDMA allocation IE). The second target base station may transfer a ranging response (AAI_RNG-RSP) message including the CDMA allocation information element to the mobile terminal (S508).

  The mobile terminal can transfer the ranging request message to the second target base station through the resource area represented by the CDMA allocation information element. At this time, the mobile terminal transfers the base station identifier (BSID = 3) of the previous serving base station and the station identifier (STID = 2) used in the previous serving base station to the second target base station through the ranging request message. (S509).

  The second target base station that has received the ranging request message from the mobile terminal can know the base station that the mobile terminal has previously received from the BSID included in the ranging request message. Accordingly, the second target base station can request the mobile terminal related information (AMS information) matched with the STID of the mobile terminal from the serving base station (S510).

  When the serving base station receives a request for mobile terminal related information from the second target base station within the resource maintenance timer, the serving base station can transfer information on the corresponding mobile terminal to the second target base station. Here, the mobile terminal related information includes a medium access control address (MAC address) of the mobile terminal, general performance (Capability) of the mobile terminal, security related parameters (for example, security performance and authentication key (AK), etc.) and nonce (Nonce). ) May be included (S511).

  The second target base station can authenticate the mobile terminal using the shared security related parameters, nonce, authentication key, and the like (S512a, S512b).

  In response to the step S509, the second target base station sends a ranging response (AAI_RNG-RSP) message including a new station identifier (STID) that uniquely identifies the mobile terminal at the second target base station and an updated nonce. Can be transferred to the mobile terminal. At this time, the ranging response message may further include a CMAC tuple valid at the second target base station (C513 Tuple) (S513).

  If the authentication procedure (steps S512a and S512b) is performed after the handover ranging procedure is completed, the second target base station may use a temporary to protect the MAC address for the mobile terminal instead of the new station identifier. The station identifier (Temporary STID) can be included in the ranging response message and transferred.

  The mobile terminal can perform normal information exchange with the second target base station using the assigned STID (S514).

  FIG. 6 shows another embodiment of the present invention, and shows one method for performing an uncontrolled handover to a neighboring base station when a handover to a handover target base station fails.

  FIG. 6 shows that when a mobile terminal (AMS) performs network re-entry to another target base station in an uncontrolled handover situation, a station identifier (STID) that uniquely identifies the mobile terminal at the target base station is efficient. The method assigned to is disclosed. FIG. 6 shows a case where a first type uncontrolled handover similar to that in FIG. 3 is performed.

  In FIG. 6, the station identifier (STID) assigned to the mobile terminal (AMS) is “2”, the serving base station identifier (BSID) is “3”, and the first target among the candidate base stations It is assumed that the identifier of the base station is “4” and the identifier of the second target base station to which the mobile terminal is to be handed over is “5”.

  The mobile terminal can transfer a handover request message to the serving base station to start handover (S601).

  Step S601 is performed only when the mobile terminal starts handover, and may not be performed when the serving base station starts handover. That is, step S601 may be selectively performed according to the handover situation.

  The serving base station (BSID = 3) can transfer a handover request (AAI_HO-REQ) message including information (AMS information) about the mobile terminal to one or more candidate base stations. However, in this document, for the sake of simplicity, it is assumed that the serving base station transfers a handover request message to a specific first target base station (BSID = 4) (S602).

  The first target base station (BSID = 4) has a dedicated ranging code, a ranging opportunity, an action time parameter, and UAI / AI used when the mobile terminal re-enters the network. A handover response message including handover related information can be transferred to the serving base station through the backbone network (S603).

  The serving base station can include handover related information and recommended candidate base station (for example, BSID = 4) in a handover command (AAI_HO-CMD) message and transfer it to the mobile terminal (S604).

  When the mobile terminal wants to perform a handover to a target base station other than the target base station recommended by the serving base station, a handover instruction (AAI_HO-IND) including information on the desired target base station (for example, BSID = 5) The message can be transferred to the serving base station. At this time, the handover instruction message may be transferred with the event code set to 2 (code 2) (S605).

  In this way, the serving base station knows that the target base station to which the mobile terminal performs handover is the second target base station. Therefore, according to user requirements, the serving base station can reset the resource maintenance timer and provide information on the mobile terminal to the second target base station.

  The mobile terminal may enter a cell region of the second target base station (BSID = 5) desired by itself and receive a preamble or superframe header (SFH) periodically broadcast from the second target base station. it can. That is, the mobile terminal can match downlink synchronization (DL sync.) With the second target base station using the preamble or SFH (S606).

  The mobile terminal may transfer a contention-based CDMA ranging code to the second target base station on the first ranging opportunity after aligning downlink synchronization to perform a network re-entry procedure to the second target base station. Yes (S607).

  The second target base station (BSID = 5) that has received the contention-based CDMA ranging code from the mobile terminal can allocate a resource area for the mobile terminal to perform a network re-entry procedure. Such allocation information regarding the resource area may be included in the CDMA allocation information element (CDMA allocation IE). The second target base station may transfer a ranging response (AAI_RNG-RSP) message including the CDMA allocation information element to the mobile terminal (S608).

  The mobile terminal can transfer the ranging request message to the second target base station through the resource area represented by the CDMA allocation information element. At this time, the mobile terminal transfers the base station identifier (BSID = 3) of the previous serving base station and the station identifier (STID = 2) used in the previous serving base station to the second target base station through the ranging request message. (S609).

  The second target base station that has received the ranging request message from the mobile terminal can know the base station that the mobile terminal has previously received from the BSID included in the ranging request message. Therefore, the second target base station can request the serving base station for information (AMS information) related to the mobile terminal matched with the STID of the mobile terminal (S610).

  When the serving base station receives a request for information on the mobile terminal from the second target base station within the resource maintenance timer, the serving base station can transfer the relevant mobile terminal related information to the second target base station. At this time, the mobile terminal related information includes the mobile terminal's medium access control address (MAC address), the mobile terminal's general performance (Capability), security related parameters (for example, security performance and authentication key (AK)), and nonce (Nonce). ) May be included (S611).

  The second target base station can authenticate the mobile terminal using the shared security related parameters, nonce, authentication key, and the like (S612a, S612b).

  In response to step S609, the second target base station sends a ranging response (AAI_RNG-RSP) message including a new station identifier (STID) that uniquely identifies the mobile terminal at the second target base station, an updated nonce, and the like. It can be transferred to the mobile terminal. At this time, the ranging response message may further include a CMAC tuple valid in the second target base station (C613 Tuple) (S613).

  If the authentication procedure (steps S612a and S612b) is performed after the handover ranging procedure is finished, the second target base station may use a temporary to protect the MAC address for the mobile terminal instead of the new station identifier. The station identifier (Temporary STID) can be included in the ranging response message and transferred.

  The mobile terminal can perform normal information exchange with the second target base station using the assigned STID or temporary station identifier (S614).

  FIG. 7 is a diagram showing another example of the present invention and another example of a method for performing an uncontrolled handover to a neighboring base station when a handover to a handover target base station fails.

  The non-control handover in FIG. 7 is basically the same as the non-control handover procedure in FIG. Therefore, for the description of steps S701 to S705 of FIG. 7, refer to the description of steps S601 to S605 of FIG.

  Since the serving base station receives the handover instruction message in step S705, the serving base station can know the second target base station to which the mobile terminal performs handover. Accordingly, the serving base station sends a handover request (HO-REQ) message including information on the mobile terminal and / or the serving base station identifier (BSID = 3) to the second target base station desired by the mobile terminal through the backbone network. Can be transferred. At this time, the information on the mobile terminal may include a mobile terminal context, a station identifier, a general capability of the mobile terminal, security related information, and a medium access control address (MAC address) of the mobile terminal (S706).

  In step S706, the target base station that has received the handover request message may store information on the mobile terminal during a predetermined period.

  The mobile terminal may enter a cell region of the second target base station (BSID = 5) desired by itself and receive a preamble or superframe header (SFH) periodically broadcast from the second target base station. it can. That is, the mobile terminal can match the downlink synchronization (DL sync.) With the second target base station using the preamble or SFH (S707).

  The mobile terminal may transfer a contention-based CDMA ranging code to the second target base station on the first ranging opportunity after aligning downlink synchronization to perform a network re-entry procedure to the second target base station. Yes (S708).

  The second target base station (BSID = 5) that has received the contention-based CDMA ranging code from the mobile terminal can allocate a resource area for the mobile terminal to perform a network re-entry procedure. Such allocation information regarding the resource area may be included in the CDMA allocation information element (CDMA allocation IE). The second target base station may transfer a ranging response (AAI_RNG-RSP) message including the CDMA allocation information element to the mobile terminal (S709).

  The mobile terminal can transfer the ranging request message to the second target base station through the resource area represented by the CDMA allocation information element. At this time, the mobile terminal may transfer the base station identifier (BSID = 3) of the previous serving base station and the station identifier (STID = 2) used in the previous serving base station to the second target base station through the ranging request message. Yes (S710).

  When receiving the identifier of the previous serving base station (BSID = 3) and the station identifier (STID = 2) used in the previous serving base station from the mobile terminal, the second target base station receives and stores them in step S706. The mobile terminal related information (e.g., MAC address) can be obtained in comparison with the information about the mobile terminal and / or the base station identifier.

  Thus, the second target base station and the mobile terminal can immediately perform the authentication procedure without any additional procedure (S711a, S711b).

  In response to the step S710, the second target base station sends a ranging response (AAI_RNG-RSP) message including a new station identifier (new STID) that uniquely identifies the mobile terminal in the second target base station and an updated nonce. Can be transferred to the mobile terminal. At this time, the ranging response message may further include a CMAC tuple valid in the second target base station (C712) (S712).

  If the authentication procedure (steps S711a and S711b) is performed after the handover ranging procedure is finished, the second target base station may use a temporary station for protecting the MAC address for the mobile terminal instead of the new station identifier. The identifier (Temporary STID) can be included in the ranging response message and transferred.

  The mobile terminal can perform normal information exchange with the second target base station using the assigned STID (S713).

  FIG. 8 is a diagram showing still another example of a method for performing non-controlled handover to a neighboring base station when handover to a handover target base station fails, according to another embodiment of the present invention. .

  The basic assumption of FIG. 8 is the same as that of FIG. Therefore, for the description of the steps S801 to S805, refer to the description of the steps S601 to S605 in FIG.

  The serving base station (BSID = 3) transfers a handover request (HO-REQ) message including mobile terminal related information (AMS INFORMATION) to the second target base station (BSID = 5) desired by the mobile terminal. (S806).

  The second target base station (BSID = 5) uses a dedicated ranging code, a ranging opportunity, an action time parameter, and / or UAI / AI used when the mobile terminal re-enters the network. A handover response (HO-RSP) message including handover related information such as can be transferred to the serving base station through the backbone network (S807).

  The serving base station can include the received handover related information in a handover command (AAI_HO-CMD) message and transfer it to the mobile terminal (S808).

  The mobile terminal may enter a cell region of the second target base station (BSID = 5) desired by itself and receive a preamble or superframe header (SFH) periodically broadcast from the second target base station. it can. That is, the mobile terminal can match downlink synchronization (DL sync.) With the second target base station using the preamble or SFH (S809).

  In order to perform the network re-entry procedure to the second target base station, the mobile terminal transmits a CDMA ranging code to the second target base station using the dedicated ranging code and ranging opportunity in the handover related information received in step S808. Can be transferred. Alternatively, the mobile terminal may forward the contention-based CDMA ranging code to the second target base station on the first ranging opportunity after the downlink synchronization with the second target base station (S810). .

  Thereafter, steps S811 to S817 related to the ranging procedure performed by the mobile terminal with the second target base station are the same as steps S608 to S614 of FIG. 6, respectively. Accordingly, FIG. 6 may be referred to for the description of steps S811 to S817.

  FIG. 9 is a diagram illustrating a mobile terminal and a base station that can execute the embodiments of the present invention described with reference to FIGS. 2 to 8 as still another embodiment of the present invention.

  The mobile terminal can operate as a transmitter in the uplink and as a receiver in the downlink. In addition, the base station can operate as a receiver in the uplink and operate as a transmitter in the downlink.

  That is, the mobile terminal and the base station include a transmission module (Tx module) 940 and 950 and a reception module (Rx module) 960 and 970, respectively, for controlling the transfer and reception of information, data, and / or messages. And may include antennas 900, 910, etc. for transmitting and receiving information, data and / or messages. In addition, each of the mobile terminal and the base station may include processors 920 and 930 for performing the above-described embodiments of the present invention, and memories 980 and 990 capable of temporarily or continuously storing the process of the processor. .

  In particular, the processors 920 and 930 include a handover module for performing a handover procedure disclosed in each embodiment of the present invention, an encryption module (or means) for encrypting a predetermined number of timer messages, and / or A decryption module (or means) for interpreting the encrypted message can be further included. In addition, the mobile terminal and the base station of FIG. 9 may further include a low power RF (Radio Frequency) / IF (Intermediate Frequency) module.

  A transmission module and a reception module included in a mobile terminal and a base station include a packet modulation / demodulation function for data transfer, a high-speed packet channel coding function, an Orthogonal Frequency Division Multiple Access (OFDMA) packet scheduling, and time division. Duplex (TDD) packet scheduling and / or channel multiplexing functions may be performed.

  The processor included in the mobile terminal and the base station depends on the control function for performing the non-cooperative handover of the present invention described above, the handover function, the authentication and encryption function, the service characteristics, and the propagation environment. A MAC (Medium Access Control) frame variable control function, a high-speed traffic real-time control function, and / or a real-time modem control function can be performed.

  The apparatus described with reference to FIG. 9 is a means that can implement the method described with reference to FIGS. The embodiment of the present invention can be implemented using the components and functions of the mobile terminal and base station apparatus described above.

  The processor 920 provided in the mobile terminal includes a handover module that can control handover. The mobile terminal can perform a handover function using a handover module.

  The mobile terminal processor 920 can monitor the handover conditions described in FIG. 1 and FIG. If the handover start condition is satisfied, the processor 920 may include the mobile terminal related information in the handover request message and control the transmission module 940 to transfer the handover request message from the antenna 900 to the serving base station. .

  Also, the receiving module 960 of the mobile terminal receives the handover command message transferred from the serving base station and transmits it to the processor 920. The processor stores the handover related information included in the handover command message in the memory. The handover operation can be performed using the handover related information.

  The processor of the mobile terminal can determine whether to perform the control handover or the non-control handover described above, and in the embodiment of the present invention, the non-control handover is performed. Accordingly, the mobile terminal can transfer the handover instruction message to the base station using the processor, the transmission module, and the antenna.

  The mobile terminal can perform the network re-entry procedure described in FIG. 3 to FIG. 8 with the target base station using the handover module included in the processor, and transmits the corresponding message to the transmission module, the reception module, and the antenna. Can be sent and received. The processor serves to control such a handover procedure.

  The receiving module 970 of the serving base station may transmit the handover request message and / or the handover instruction message received from the antenna 910 to the processor 930. The processor 930 may store the mobile terminal related information in the memory 990 and transfer a handover command message including the handover related information to the mobile terminal via the transmission module 950.

  The target base station can perform the network re-entry procedure described in FIGS. 3 to 8 with the mobile terminal using the antenna, the transmission module, and the reception module. That is, the target base station can manage the handover procedure using the handover module of the processor and can transmit / receive a message for performing an operation based on the procedure to / from the mobile terminal.

  On the other hand, in the present invention, a mobile terminal includes a personal digital assistant (PDA), a cellular phone, a personal communication service (PCS) phone, a GSM (Global System for Mobile) phone, and a WCDMA (dedicated WCDMA) phone. CDMA) phone, MBS (Mobile Broadband System) phone, handheld PC (Hand-Held PC), notebook PC, smart phone or multi-mode multi-band (MM-MB) terminal Can be used.

  Here, a smartphone is a terminal that combines the merits of a mobile communication terminal and a personal mobile terminal, and data such as schedule management, fax transmission / reception, and Internet connection, which are functions of the personal mobile terminal, are added to the mobile communication terminal. It means a terminal that combines communication functions. The multi-mode multi-band terminal incorporates a multi-modem chip, and is a mobile Internet system and other mobile communication systems (for example, a CDMA (Code Division Multiple Access) 2000 system, a WCDMA (Wideband CDMA) system, etc.). A terminal that can operate in either case.

  Embodiments according to the present invention can be implemented by various means such as hardware, firmware, software, or a combination thereof.

  In the case of implementation by hardware, the method according to an embodiment of the present invention may include one or more ASICs (application specific integrated circuits), DSPs (digital signal processor), DSPS (digital signal processing), DSPDs (digital signal processing). devices), FPGAs (field programmable gate arrays), processors, controllers, microcontrollers, microprocessors, and the like.

  In the case of implementation by firmware or software, the method according to the embodiment of the present invention may be in the form of a module, procedure, function, or the like that performs the function or operation described above. For example, software code may be stored in memory units 980 and 990 and driven by processors 920 and 930. The memory unit is provided inside or outside the processor, and can exchange data with the processor by various known means.

  It will be apparent to those skilled in the art that the present invention can be embodied in other specific forms without departing from the technical spirit and essential features of the invention. Accordingly, the above detailed description should not be construed as limiting in any respect and should be considered as exemplary. The scope of the invention should be determined by reasonable analysis of the appended claims, and thus all modifications within the equivalent scope of the invention are included in the scope of the invention. It is obvious that claims which do not have an explicit citation relationship in the claims can be combined to constitute an embodiment, or can be included as new claims by amendment after application.

  Each embodiment of the present invention can be applied to various wireless connection systems. Examples of various wireless access systems include 3GPP (3rd Generation Partnership Project), 3GPP2 and / or IEEE 802. xx (Institute of Electrical and Electronic Engineers 802) system. Each embodiment of the present invention can be applied to any technical field to which the various wireless connection systems are applied in addition to the various wireless connection systems.

Claims (18)

A method for performing uncontrolled handover in a mobile station (MS) , comprising:
The mobile station determining whether a serving base station resource maintenance timer has expired , the resource maintenance timer indicating a time during which the serving base station maintains the mobile station context; and ,
Used by the serving base station to identify the base station identifier of the serving base station and the mobile station during a network re-entry procedure to a target base station (TBS) if the resource maintenance timer has not expired. The mobile station transmitting a ranging request message including a station identifier to the target base station;
In response to the ranging request message, the mobile station receives a ranging response message from the target base station, the ranging response message identifying the mobile station when a new station identifier is not assigned. Including a temporary station identifier to be used for, or a new station identifier to be used by the target base station to identify the mobile station;
Have
The non-control handover method , wherein the ranging request message and the ranging response message are used for the non-control handover. If the target base station is determined in advance as the target base station desired by the mobile station and the target base station is not a candidate base station recommended by the serving base station, or the mobile station is If it can not reach the recommended which candidate base station, the non-control handover is started, uncontrolled handover method of claim 1.   The uncontrolled handover method according to claim 2, further comprising a step of receiving a handover command message including handover related information and information on the candidate base station from the serving base station. The handover related information includes at least one of an operation time parameter indicating the start of the network re-entry procedure, a handover ranging code used in the candidate base station, and a ranging opportunity used in the candidate base station. The uncontrolled handover method according to claim 3. The mobile station receives the handover instruction message including an event code instructing the start of the uncontrolled handover and an identifier for identifying that the target base station is the desired target base station of the mobile station. The non-controlled handover method according to claim 3, further comprising a step of transmitting to a base station. Transmitting a ranging code from the mobile station to the target base station to perform the network re- entry procedure;
As a response to the ranging code, the mobile station receiving from the target base station a ranging message including allocation information related to a resource region allocated to the ranging procedure;
Further comprising
The non-control handover method according to claim 2, wherein the ranging request message is transmitted in the resource region represented by the allocation information. The uncontrolled handover method according to claim 2 , wherein the ranging response message further includes a CMAC tuple. A method for performing an uncontrolled handover between a mobile station (MS) , a serving base station (SBS), and a target base station (TBS),
During a network re-entry procedure, the target base station sends a ranging request message including a station identifier used by the serving base station to identify the base station identifier of the serving base station and the mobile station from the mobile station. Receiving step;
In response to the ranging request message, the target base station transmits to the mobile station a ranging response message including a new station identifier that is to be used by the target base station to identify the mobile station. When,
Have
The non-control handover method , wherein the ranging request message and the ranging response message are used for the non-control handover. The target base station is determined in advance If it is desired to target base station of the mobile station, wherein if the target base station is not a candidate base station recommended by the serving base station, or the mobile station by the serving base station 9. The non-controlled handover method according to claim 8 , wherein if no recommended candidate base station is reachable, the non-controlled handover is triggered . In the target base station, the method comprising: a ranging code for performing the network re-entry procedure, receiving from the mobile station,
As a response to the ranging code, transmitting a ranging message including allocation information related to a resource region allocated to the ranging procedure from the target base station to the mobile station;
Further comprising
The non-control handover method according to claim 9 , wherein the ranging request message is transmitted in the resource region represented by the allocation information.   The uncontrolled handover method according to claim 9, wherein the security information includes a CMAC tuple. A mobile station (MS) that performs uncontrolled handover,
A transmission module;
A receiving module;
Memory,
A processor operatively connected to the transmitting module, the receiving module and the memory;
Have
The processor is
Determine if the serving base station resource maintenance timer has expired,
If the resource maintenance timer has not expired, a ranging request message including a base station identifier of the serving base station and a station identifier used by the serving base station to identify the mobile station during a network re-entry procedure To the target base station ,
A temporary station identifier used to identify the mobile station when no new station identifier is assigned in response to the ranging request message, or a new station identifier for the target base station to identify the mobile station Is configured to receive a ranging response message including the target base station,
The resource maintenance timer indicates a time during which the serving base station maintains the context of the mobile station ,
The ranging request message and the ranging response message are used for the uncontrolled handover . The target base station is determined in advance If it is desired to target base station of the mobile station, wherein if the target base station is not a candidate base station recommended by the serving base station, or the mobile station by the serving base station 13. A mobile station according to claim 12 , wherein if no recommended candidate base station is reachable, the uncontrolled handover is initiated . The mobile station according to claim 13 , wherein the processor is configured to receive a handover command message including handover related information and information on the candidate base station from the serving base station. The handover related information includes at least one of an operation time parameter indicating the start of the network re-entry procedure, a handover ranging code used in the candidate base station, and a ranging opportunity used in the candidate base station. The mobile station according to claim 14 . The processor transmits the handover instruction message including an event code instructing start of the uncontrolled handover and an identifier for identifying that the target base station is the desired target base station of the mobile station. The mobile station according to claim 13 , further configured to transmit to the serving base station using a module . The processor transmits a ranging code to the target base station to perform the network re- entry procedure, and receives a ranging message including allocation information regarding a resource region allocated to the ranging procedure as a response to the ranging code. Further configured as
The mobile station according to claim 13 , wherein the ranging request message is transmitted in the resource area represented by the allocation information. The mobile station according to claim 13 , wherein the security information includes a CMAC tuple.

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