KR101670749B1 - Method for efficiently performing Coverage Loss Operation during Sleep Mode in a Broadband Wireless Access System - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates generally to a broadband wireless access system, and more particularly, to a method for detecting an area outage during operation of a mobile terminal in a sleep mode and a subsequent operation procedure therefor. A method for detecting a region out of a terminal operating in a sleep mode in a broadband wireless access system according to an exemplary embodiment of the present invention includes detecting whether a sleep mode of a sleep cycle is a sleep window at a first time point when a super frame header (SFH) A step waking up; Detecting the superframe header; And operating the sleep window or the listening window according to the sleep cycle if the detection result is successful, and awake until the detection result indicates that the superframe header is successfully detected if the detection result is unsuccessful.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for performing a zone-departure operation in a sleep mode in a broadband wireless access system,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates generally to a broadband wireless access system, and more particularly, to a method for detecting an area outage during operation of a mobile terminal in a sleep mode and a subsequent operation procedure therefor.

For mobility, it is very important to reduce power consumption of terminals that rely on battery power. Therefore, various methods for reducing power consumption have been proposed, and sleep mode is one of them.

The sleep mode is a state in which the terminal stops operation of a terminal that no longer has traffic to transmit / receive to / from the base station, thereby reducing power consumption.

The MS communicates with the BS in a normal mode or an active mode and transmits a sleep request message (MOB_SLP-REQ or AAI_SLP-REQ) message to enter a sleep mode when there is no more traffic to be transmitted / To the base station. The base station receiving the sleep request message transmits a sleep response (MOB_SLP-RSP or AAI_SLP-RSP) message including parameters related to the sleep mode of the terminal such as an initial sleep cycle, a listening window (LW) send.

The terminal receiving the sleep response message enters the sleep mode using the parameters related to the sleep mode.

During the sleep mode, the terminal alternately repeats a sleep interval and a listening interval. The UE can transmit / receive data to / from the BS during the listening interval, and can not transmit / receive data to / from the BS during the sleep interval, thereby buffering data arriving at the BS during the sleep interval.

The above-described sleep mode operation will be described in more detail with reference to FIG.

1 is a diagram illustrating an example of a sleep mode operation procedure of a UE in a general IEEE 802.16 system.

Referring to FIG. 1, after a UE transitions from a normal mode to a sleep mode, a first sleep cycle includes only a sleep window. From the second sleep cycle, the sleep window and the listening window are included. The length of the first sleep cycle is the initial sleep cycle included in the sleep response message.

During the listening window, the terminal receives a traffic indication (TRF-IND) message from the base station to inform the base station whether there is traffic to be transmitted to the terminal. If the traffic indication message includes a negative indication, it means that there is no traffic to be transmitted to the terminal, and if the traffic indication message includes a positive indication, the base station has traffic to be transmitted to the terminal.

1, when the MS receives a traffic indication message including an indefinite indication during the listening window of the second sleep cycle, it determines that there is no traffic to be transmitted on the downlink, and increases the sleep cycle to twice the previous sleep cycle.

Upon receiving a traffic indication message including an indefinite indication, the UE increases the sleep cycle according to Equation (1) below.

Referring to Equation (1), the UE sets the current sleep cycle to twice the previous sleep cycle and the last sleep cycle included in the sleep response message, whichever is smaller. That is, the UE can not set a sleep cycle larger than the last sleep cycle. This is to prevent the slip cycle from continuously increasing.

During the listening window of the third sleep cycle, the MS resets the sleep cycle to the initial sleep cycle upon receipt of the traffic indication message including the positive indication.

The terminal may then transmit and receive traffic to and from the base station during the listening window included in the MOB_SLP-RSP message. At this time, if the traffic transmission / reception with the base station can not be terminated during the listening window included in the sleep response message, the mobile station continues to transmit / receive traffic with the base station by extending the listening window. During the extended listening window, the terminal transmits and receives traffic to and from the base station, and upon receiving the last PDU indicator or listening window termination flag from the base station, it can stop extending the listening window and enter the sleep window.

In the IEEE 802.16m system, the MOB_SLP-REQ / RSP message can be replaced with the AAI_SLP-REQ / RSP message, respectively. In addition, when the UE enters the sleep mode, the UE receives a Sleep Cycle Identifier (SCID) corresponding to the traffic characteristic through the exchange of AAI_SLP-REQ / RSP. SCID is an identifier for a sleep mode terminal to which all parameters (Initial Sleep cycle, Listening window length, TIMF flag, LWEF flag, Final sleep cycle, NSCF, T_AMS Timer, etc.) are mapped after the UE enters the sleep mode. Also, the UE and the BS can switch the SCID (SCID switching) or change the parameter value (mapped to the SCID) in consideration of the traffic characteristics of the UE during the sleep mode.

On the other hand, uplink data may not be transmitted from the UE for a predetermined time or feedback (ACK or NACK) for downlink data may not be transmitted to the BS. At this time, the base station can trigger a resource retention timer and facilitate the re-entry of the terminal's network by storing the terminal's connection context. This method is implicitly provided in a general mobile communication system. Since the point of time when the base station judges that the mobile station has left the coverage of the network and the reference are not clear, the base station unnecessarily stores the connection information of the mobile station You may have to.

For this reason, in a general IEEE 802.16m system, when a mobile station moves out of a coverage area of a serving base station, synchronization delays between a base station and a mobile station may occur, resulting in a DCR (Deregistration) with Context Retention mode and Coverage loss recovery mode are defined.

However, since the terminal operating in the sleep mode and operating in the sleep mode performs normal data transmission / reception only in the listening window, it is determined through a certain procedure whether or not the terminal is out of the area. As a result, Is not defined.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for determining whether or not a terminal operating in a sleep mode is out of the area and an apparatus for performing the same.

It is another object of the present invention to provide an efficient network re-entry procedure and an apparatus for performing the same when a terminal operating in a sleep mode detects an area out.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, unless further departing from the spirit and scope of the invention as defined by the appended claims. It will be possible.

In order to solve the above problems, a method for detecting an area outage of a terminal operating in a sleep mode in a broadband wireless access system according to an embodiment of the present invention includes a step of transmitting a superframe header (SFH) A step of waking up at any one time point regardless of whether the sleeping window of the sleep cycle is present; Detecting the superframe header; And operating the sleep window or the listening window according to the sleep cycle if the detection result is successful, and awake until the detection result indicates that the superframe header is successfully detected if the detection result is unsuccessful.

In this case, it is preferable that the first time point is a time point at which a superframe header immediately before the sleep window ends is transmitted.

Scanning the new channel if the detection of the superframe header fails consecutively for a predetermined number of times; And a ranging target indication field set to a value indicating the network re-entry by the coverage loss (Coverage Loss) in association with the connection information of the terminal to the base station found as a result of the scan Transmitting a first message to the discovered base station; And receiving a second message from the discovered base station, the second message including optimization information indicating a procedure that can be omitted from the network re-entry.

Transmitting a handover ranging code to the found base station; Receiving a third message including a transmission result of the handover ranging code from the found base station; And receiving uplink resource allocation information from the found base station if the transmission result is successful, wherein the step of transmitting the first message includes: receiving uplink resource indicated by the uplink resource allocation information . ≪ / RTI >

The first message is a ranging request message (AAI_RNG-REQ) message, the second message is a ranging response message (AAI_RNG-RSP) message, the third message is a ranging acknowledgment message ) Message, the identifier is a context preservation identifier (CRID), the value indicating the network re-entry due to the zone shift is 0b1000, and the optimization information is a reentry process optimization parameter.

A method for determining whether a coverage loss of a terminal operating in a sleep mode in a broadband wireless access system according to an exemplary embodiment of the present invention is a method for determining whether a coverage loss of a terminal Transmitting first UL resource allocation information (UL grant) from the listening window closest to the MS to the MS; And resetting the first timer when a response signal is received from the terminal through an uplink resource indicated by the first uplink resource allocation information, and when the response signal is not received, And transmitting at least one second uplink resource allocation information to the UE.

Transmitting a first message for requesting a ranging operation to the terminal and starting a second timer when the response signal is not received from the terminal for a predetermined number of times; And restarting the first timer if the second message indicating that the ranging is successful is received from the terminal before the expiration of the second timer.

The method may further include starting a third timer if the second message is not received before the second timer expires.

Also, the response signal may include a Medium Access Control Protocol Data Unit (MAC PDU) including predetermined data and a bandwidth request header (BR Header) having a requesting BR size of zero.

In addition, the first message is an unsolicited AAI_RNG-RSP message, the second message is a ranging acknowledgment (AAI_RNG-CFM) message, the first timer is an active BS timer (Active_BS_Timer) Preferably, the second timer is a T58 timer, and the third timer is a resource retention time.

A terminal device performing a sleep mode in a broadband wireless access system according to an embodiment of the present invention includes a processor; And a wireless communication (RF) module for transmitting / receiving a radio signal to / from the outside according to the control of the processor, wherein the processor is configured to perform a sleep cycle at a first time point at which a superframe header (SFH) The sleep window or the listening window according to the sleep cycle if the detection result is successful, and if the detection result is not successful, It can be controlled so as to be awake until the superframe header is successfully detected.

In this case, it is preferable that the first time point is a time point at which a superframe header immediately before the sleep window ends is transmitted.

In addition, when the detection of the superframe header fails consecutively for a predetermined number of times, the processor scans a new channel and transmits an identifier for identifying the terminal to the discovered base station in association with the connection information of the terminal And a ranging target indication field set to a value indicating a network re-entry by coverage loss, to be transmitted to the found base station, and instructs a procedure that can be omitted in the network re-entry A second message containing optimization information to be received from the found base station.

Also, the processor may transmit a handover ranging code to the found base station, receive a third message including a transmission result of the handover ranging code from the found base station, It is preferable that the uplink resource allocation information is received from the found base station, and the first message is transmitted using the uplink resource indicated by the uplink resource allocation information.

The first message is a ranging request message (AAI_RNG-REQ) message, the second message is a ranging response message (AAI_RNG-RSP) message, the third message is a ranging acknowledgment message ) Message, the identifier is a context preservation identifier (CRID), the value indicating the network re-entry due to the zone shift is 0b1000, and the optimization information is a reentry process optimization parameter.

According to the embodiments of the present invention, the following effects are obtained.

First, a terminal operating in a sleep mode can determine whether a region has departed by allowing the terminal to awake until it receives a superframe header normally.

Second, the UE operating in the sleep mode through the network reentry procedure disclosed in the embodiments of the present invention can efficiently perform an optimized network reentry procedure.

The effects obtained by the present invention are not limited to the above-mentioned effects, and other effects not mentioned can be clearly understood by those skilled in the art from the following description will be.

1 is a diagram illustrating an example of a sleep mode operation procedure of a UE in a general IEEE 802.16 system.
FIG. 2 shows an example of a method of detecting an area shift of a base station, which can be applied to embodiments of the present invention.
FIG. 3 shows an example in which a sleep mode terminal according to an embodiment of the present invention succeeds in receiving a super frame header in a sleep window.
FIG. 4 illustrates an example of a case where a sleep mode terminal fails to receive a superframe header in a sleep window according to an embodiment of the present invention.
FIG. 5 shows an example of the area release recovery procedure according to an embodiment of the present invention.
6 shows an example of a sleep mode operation procedure of a UE according to another embodiment of the present invention.
7 shows an example of a sleep mode operation procedure of a UE according to another embodiment of the present invention.
FIG. 8 shows an example of a sleep mode operation procedure of a terminal according to another embodiment of the present invention.
9 is a block diagram showing an example of a structure of a transmitting end and a receiving end as another embodiment of the present invention.

The present invention relates to a wireless access system. Embodiments of the present invention will now be described in detail with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown.

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

In the description of the drawings, there is no description of procedures or steps that may obscure the gist of the present invention, nor is any description of steps or steps that can be understood by those skilled in the art.

Herein, the embodiments of the present invention have been described with reference to the data transmission / reception relationship between the base station and the terminal. Herein, the base station is a terminal node of a network that directly communicates with the terminal. The specific operation described herein as performed by the base station may be performed by an upper node of the base station, as the case may be.

That is, various operations performed for communication with a terminal in a network consisting of a plurality of network nodes including a base station can be performed by a base station or other network nodes other than the base station. At this time, the 'base station' may be replaced by terms such as a fixed station, a Node B, an eNode B (eNB), an access point, and the like. In addition, 'Mobile Station (MS)' may be replaced with terms such as User Equipment (UE), Subscriber Station (SS), Mobile Subscriber Station (MSS) or Mobile Terminal.

Also, the transmitting end refers to a node that transmits data or voice service, and the receiving end refers to a node that receives data or voice service. Therefore, in the uplink, the terminal may be the transmitting end and the base station may be the receiving end. Similarly, in the downlink, the terminal may be the receiving end and the base station may be the transmitting end.

Meanwhile, the mobile terminal of the present invention may be a PDA (Personal Digital Assistant), a cellular phone, a PCS (Personal Communication Service) phone, a GSM (Global System for Mobile) phone, a WCDMA (Wideband CDMA) Etc. may be used.

Embodiments of the present invention may be implemented by various means. For example, embodiments of the present invention may be implemented by hardware, firmware, software, or a combination thereof.

For a hardware implementation, the method according to embodiments of the present invention may be implemented in one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs) , Field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, and the like.

In the case of an implementation by firmware or software, the method according to embodiments of the present invention may be implemented in the form of a module, a procedure or a function for performing the functions or operations described above. The software code can be stored in a memory unit and driven by the processor. The memory unit may be located inside or outside the processor, and may exchange data with the processor by various well-known means.

Embodiments of the present invention may be supported by standard documents disclosed in at least one of the IEEE 802 systems, 3GPP systems, 3GPP LTE systems and 3GPP2 systems, which are wireless access systems. That is, the steps or portions of the embodiments of the present invention that are not described in order to clearly illustrate the technical idea of the present invention can be supported by the documents. In addition, all terms disclosed in this document may be described by the standard document. In particular, embodiments of the present invention may be supported by one or more of the documents P802.16-2004, P802.16e-2005 and P802.16Rev2, which are standard documents of the IEEE 802.16 system.

The specific terminology used in the following description is provided to aid understanding of the present invention, and the use of such specific terminology may be changed into other forms without departing from the technical idea of the present invention.

This specification assumes an IEEE 802.16 system. In particular, the following terminal is an AMS (Advanced Mobile Station) satisfying a standard defined by the IEEE 802.16m standard, and the base station is assumed to be an Advanced Base Station (ABS) of the same standard standard.

Coverage Loss

First, we define "coverage loss" that can be applied to embodiments of the present invention.

The area offset refers to a situation where a temporary signal loss occurs due to fading due to movement of the mobile station to an area outside the service area (i.e., coverage) of the base station.

Next, an active base station timer (active_ABS_timer) is defined.

The active base station timer is a timer that the base station maintains for each terminal. The active base station timer can be started upon completion of the completion of the initial network entry upon completion of the exchange of the registration request / response (AAI_REG-REQ / AAI_REG-RSP) message between the mobile station and the base station. Alternatively, the active base station timer may be started according to the completion of network reentry according to the HO process Optimization included in the ranging response message. This active base station timer can be reset when the base station receives data from the terminal. Examples of the data include an MPDU (Medium Access Control Protocol Data Unit) or feedback information.

In another case where the active base station timer starts, when the mobile station serving as the serving base station performs handover to another target base station, the base station notifies the handover completion notification (HO completion notification) from the network through the backbone network And can not be started until a preset time is reached. At this time, it is preferable that the predetermined time is a time point indicated by the ranging starting deadline (Ranging_Initiation_Deadline) information.

Next, a resource retention timer is defined.

When the Active_ABS timer for a specific terminal expires, the base station goes through a predetermined procedure to determine whether the terminal is out of the area. Such a procedure is hereinafter referred to as "coverage loss detection" for convenience. The detailed process of the area departure detection operation will be described later. If there is no response from the mobile station after completing the procedure, the base station can start the resource retention timer. If the resource retention timer expires, the base station can release the context of the corresponding mobile station.

It also defines an active terminal timer (Active_AMS_Timer).

Like the active base station timer described above, the active terminal timer is configured to transmit the AAI_REG-REQ-RSP message to the mobile station according to the completion of the initial network entry upon completion of the AAI_REG-REQ / AAI_REG- Lt; / RTI > Alternatively, the active base station timer may be started according to the completion of network reentry according to the HO process Optimization included in the ranging response message. While the active terminal timer is being maintained (i.e., before the expiration of the active terminal timer), the terminal can know that its own connection context is stored in the network.

Next, a context preservation identifier (CRID) is defined.

The CRID may be assigned to the terminal from the base station via the Registration Response (AAI_REG-RSP) message. The CRID is an identifier that can be used to identify a corresponding terminal on a network (in particular, a base station or an entity (e.g., Authenticator ASN-GW) that preserves the connection context of the terminal. And may be used to identify a terminal operating in a DCR (Deregistration with Context Retention) mode. The CRID may be assigned to a UE through a registration response message as described above, (AAI_RNG-RSP) message or a deregistration response (AAI_DREG-RSP) message upon entering the DCR mode.

Hereinafter, a method of detecting a zone-departure of a terminal and a base station using the timers defined above will be described with reference to FIG.

FIG. 2 shows an example of a method of detecting an area shift of a base station, which can be applied to embodiments of the present invention.

Referring to FIG. 2, a base station transmits an active base station timer for a corresponding mobile station, and an active mobile station timer for a mobile station according to completion of an initial network entry of the mobile station or completion of network reentry (S201).

In this case, the network initial entry can be completed by completing the exchange of the AAI_REG-REQ / AAI_REG-RSP message, and the network re-entry can be completed by the HO process Optimization ) May be determined according to the following equation. In case of initial entry into the network, a context retention identifier (CRID) may be allocated to the UE through a AAI_REG-RSP message. In case of network re-entry, a new CRID is transmitted to the UE through a ranging response (AAI_RNG- Can be assigned.

At this time, if the active BS timer for the MS expires, the BS may allocate an UL burst to confirm the status of the MS (S202).

The MS can transmit an MPDU or a bandwidth request header (BR Header) having a requested bandwidth size of 0 through an uplink resource (UL grant) allocated thereto in response to the UL grant. The active base station timer can be reset when the BS receives the bandwidth request header .

However, it is also possible for the BS to transmit certain data (including MAC PDUs or BRs including data) from the UE through uplink resources indicated by consecutive UL grants (Coverage Loss Detection UL grants) of a predetermined number (N _{CLD_UL_Grant} ) Header) may not be received (S203, S204).

In this case, the BS may transmit an Unsolicited AAI_RNG-RSP message to the UE to allow the UE to perform periodic ranging using a periodic ranging code. For this, the base station can set the ranging request bit of the ranging response message to '1' (S205).

At this time, the base station may start a timer (e.g., a retry timer or a T58 timer) indicating a time to wait for reception of a message (AAI_RNG-CFM) for confirmation of ranging.

In response to the ranging request of the base station, the terminal may transmit the periodic ranging code to the base station (S206).

The base station transmits a ranging acknowledgment (AAI_RNG-ACK) message to the mobile station in response to the ranging code (S207). In this case, the ranging acknowledgment message may include a ranging status indicating whether or not the ranging is successful and a corresponding ranging code transmitted from the terminal.

The MS may transmit a ranging acknowledgment (AAI_RNG-CFM) message to the BS in response to the ranging acknowledgment message (S208). At this time, the terminal can include its station identifier (STID) in the ranging acknowledgment message.

Upon receiving the ranging acknowledgment message transmitted by the mobile station, the base station can update the active base station timer (S209).

If the AAI_RNG-CFM message is not received until the T58 timer expires, the base station starts resource retention time, releases the dynamic context of the corresponding terminal, and transmits the static context to the context of the terminal To the network object that stores it.

On the other hand, when the mobile station loses the physical layer synchronization (PHY synchronization), the downlink synchronization (DL sync), or the uplink synchronization (UL sync) with the base station, For example, if the UE can not continuously receive a superframe header (SFH) of a predetermined number of times (N _LOST-SFH ) from the base station, it can determine that the base station has deviated from the base station.

First Embodiment

According to an embodiment of the present invention, it is proposed that the terminal operating in the sleep mode determines whether or not the area is out of service through the successful reception of the superframe header.

Hereinafter, a method of receiving a superframe header according to the present embodiment and a method of determining whether or not a region has departed will be described.

The UE periodically updates the SFH in the sleep mode. That is, when the UE recognizes that the SFH has been updated through the P-SFH IE, the UE transmits the updated S-SFH SP IE at the time of transmission (for example, the corresponding S-SFH SP IE immediately before the end of the sleep window is transmitted Time) to update the SFH. However, when the terminal operating in the sleep mode wakes up to check the SFH but does not receive the SFH (for example, the listening window set on a frame-by-frame basis does not overlap with the SFH transmission position). In this case, the sleep mode terminal can wake up to confirm the SFH in the sleep window.

In particular, in the present embodiment, it is proposed that the terminal keeps awake to receive the SFH regardless of the sleep cycle (that is, awake in the sleep window) when the terminal can not receive. Thereafter, when the SFH is received, the terminal can operate again according to the sleep cycle. Conversely, if the terminal can not continuously receive the SFH for a predetermined number of times (i.e., N _LOST-SFH ), it can be determined that the terminal is in the out _-of- area state. In this case, the UE can perform a coverage loss recovery procedure. The area departure recovery procedure will be described later.

The sleep mode operation method according to the present embodiment will be described with reference to Figs. 3 to 5. Fig.

FIG. 3 shows an example when the sleep mode terminal according to the present embodiment succeeds in receiving a super frame header in the sleep window, and FIG. 4 shows an example when the super frame header reception fails. 5 shows an example of the area release recovery procedure according to the present embodiment.

Referring to FIG. 3, since the frame to which the SFH is transmitted is located in the frame before the start of the listening window, the terminal operating in the sleep mode wakes up to receive the SFH although the sleep window is not terminated. However, if the UE fails to receive the SFH, the UE continuously awakes (Awake) regardless of the listening window until the next SFH transmission time, and operates according to the sleep cycle when the SFH is received. In FIG. 3, since the time when the SFH is received is the sleep window, the terminal operates in a sleep state.

On the other hand, assuming that the N _LOST-SFH value is 4 as shown in FIG. 4, if the SFH reception fails three times and the SFH reception fails after the first SFH reception fails, Recovery procedure.

Hereinafter, the area release recovery procedure according to the present embodiment will be described in detail with reference to FIG.

FIG. 5 shows an example of a network reentry procedure of a terminal according to an embodiment of the present invention.

If it is determined that the UE is in the out-of-area state, a new channel is scanned to find the BS. If the base station is found, the mobile station can synchronize the physical (PHY) and downlink (DL) synchronization with the found base station and transmit the handover ranging code to the base station (S501). At this time, the found base station may be the same base station as the previous serving base station, or may be another base station.

The base station successfully receives the ranging code, sets a ranging acknowledgment (AAI_RNG_ACK) message as a success status, transmits the AAU_RNG_ACK message to the UE, and allocates UL BW allocation to the UE (S502, S503).

In step S504, the MS transmits a ranging request message to the BS in which the ranging target indicator is set to a value indicating a network re-entry according to the area outage (for example, 0b1000) through the allocated uplink resources. At this time, the terminal may include a CRID in the ranging request message and protect the identifier with a Cipher-based Message Authentication Code (CMAC) key generated by a new authentication key (AK) when security connection information is valid.

In step S505, the base station can request the network entity that stores the connection information of the corresponding terminal using the CRID transmitted through the ranging request message to obtain the connection information of the terminal.

In step S506, the BS determines a MAC control message that can be omitted using the acquired connection information of the MS, sets a handover optimization parameter according to the MAC control message, and transmits a ranging response (AAI_RNG-RSP) message to the MS.

That is, the reentry process can be simplified by omitting an optional procedure (Signaling, Control MAC message) through the Reentry Process Optimization parameter of the AAI_RNG-RSP message.

At this time, the ranging response message may include a station identifier (STID) for identifying a terminal in the corresponding base station, and a new CRID may be further included when the CRID is updated. If the CMAC value of the ranging request message transmitted by the UE is valid, the ranging response message can be transmitted to the UE in an encrypted form.

The terminal may then perform the network reentry procedure according to the optimization parameters.

Second Embodiment

In another embodiment of the present invention, it is proposed that the mobile station judges whether or not the mobile station is leaving the area using the active base station timer value.

The active base station timer value may be transmitted to the terminal through a predetermined MAC message in the process of entering the sleep mode of the terminal. In more detail, the UE receives an active base station timer value from the base station through an AAI_SLP-RSP message during a sleep mode initiation process. The UE can know when the UL grant is allocated to the base station to detect whether the UE is out of the area through the active BS timer value. At this time, the active base station timer is applied at a time point at which the mobile station starts to operate in the sleep mode after the sleep mode start procedure is completed (i.e., a frame indicated by the start frame number value, included in the AAI_SLP-RSP message) .

An operation procedure of the UE when the active base station timer value is included in the AAI_SLP-RSP message will be described with reference to FIG.

6 shows an example of a sleep mode operation procedure of a UE according to another embodiment of the present invention.

Referring to FIG. 6, the UE awakes at a time point when the BS allocates a UL Grant for detecting an out-of-area, allocates a UL Grant, and transmits a pending PDU through the UL resource indicated by the corresponding UL grant BR header) to the BS. After that, the terminal operates again according to the sleep cycle.

Third Embodiment

In another embodiment of the present invention, the base station proposes an effective transmission point of the UL grant allocated to the UE in order to determine whether the UE operating in the sleep mode is out of the area.

Specifically, when the active base station timer expires, the base station proposes to assign UL Grant to the terminal in the nearest listening window at the time when the active base station timer expires. This will be described with reference to FIG.

7 shows an example of a sleep mode operation procedure of a UE according to another embodiment of the present invention.

Referring to FIG. 7, since the third superframe end point at which the active base station timer expires is the sleep window period, the BS allocates UL Grant to the UE in the listening window existing in the second superframe nearest to the expiration time . Accordingly, the UE allocates a UL Grant in the listening window and transmits a pending PDU (BR header with a BR size of 0) to the BS through the UL resource indicated by the corresponding UL grant. The present embodiment is advantageous in that since the UL grant is allocated in the listening interval of the UE, it is not necessary to know the active base station timer value in the UE and it is not necessary to wake up in the sleep window.

Fourth Embodiment

In the present exemplary embodiment, the BS determines a next periodic ranging parameter indicating a time point at which the UL grant is allocated to detect whether the UE is out of the sleep mode, through a predetermined MAC message or header, It is suggested to transmit to the terminal in the listening window during the step or sleep mode operation.

Here, the next periodic ranging parameter may be an unsolicited sleep response message, and the header may be a sleep control header (SCH) or a sleep control extended header (SCEH). This will be described with reference to FIG.

FIG. 8 shows an example of a sleep mode operation procedure of a terminal according to another embodiment of the present invention.

Referring to FIG. 8, when the active BS timer ends in the sleep window of the MS, the BS transmits the next periodic ranging parameter to the MS in the previous listening window to inform the UL grant transmission time. Accordingly, the UE awakes at the point indicated by the next periodic ranging parameter, allocates a UL Grant, and transmits a pending PDU (BR header with a BR size of 0) to the base station through an uplink resource indicated by the corresponding UL grant do. After that, the terminal operates again according to the sleep cycle.

Table 1 below shows an example of the following periodic ranging parameters.

Name Value Usage Next periodic ranging This value indicates the offset of the frame in which the AMS shall be ready to perform a periodic ranging with respect to the frame where AAI_SLP-RSP / SCH / SCEH is transmitted.

Terminal and base station structure

Hereinafter, a terminal and a base station (FBS, MBS) in which the embodiments of the present invention can be performed will be described as another embodiment of the present invention.

The terminal may operate as a transmitter in an uplink and as a receiver in a downlink. In addition, the base station can operate as a receiver in an uplink and operate as a transmitter in a downlink. That is, the terminal and the base station may include a transmitter and a receiver for transmission of information or data.

The transmitter and receiver may comprise a processor, module, part and / or means, etc., for performing embodiments of the present invention. In particular, the transmitter and receiver may include a module (means) for encrypting the message, a module for interpreting the encrypted message, an antenna for transmitting and receiving the message, and the like. An example of such a transmitting end and a receiving end will be described with reference to FIG.

9 is a block diagram showing an example of a structure of a transmitting end and a receiving end as another embodiment of the present invention.

Referring to Fig. 9, the left side shows the structure of the transmitting end, and the right side shows the structure of the receiving end. Each of the transmitting end and the receiving end includes antennas 5 and 10, processors 20 and 30, transmission modules (Tx modules 40 and 50), reception modules (Rx modules 60 and 70), and memories 80 and 90 . Each component can perform a function corresponding to each other. Each component will be described in more detail below.

The antennas 5 and 10 transmit the signals generated by the transmission modules 40 and 50 to the outside or receive radio signals from the outside and transmit the signals to the reception modules 60 and 70. If a multi-antenna (MIMO) function is supported, more than two may be provided.

The antenna, the transmitting module and the receiving module can together form a wireless communication (RF) module.

The processors 20 and 30 typically control the overall operation of the mobile terminal as a whole. For example, a controller function, a service characteristic, and a MAC (Medium Access Control) frame variable control function, a handover function, an authentication and encryption function, and the like for performing the above- . More specifically, the processors 20 and 30 can perform overall control for performing the base station restart detection and the network reentry procedures shown in FIGS. 2 and 3.

In particular, the processor of the mobile terminal can awake to receive the SFH regardless of the sleep cycle at the time when the SFH is transmitted, in order to determine whether the area is out of the sleep mode. At this time, if the SFH reception fails, the processor does not switch to the sleep state and receives the next SFH in a continuously awake state. If the reception of the SFH fails a predetermined number of times, the processor of the terminal can perform the out-of-area recovery procedure. That is, the processor of the mobile terminal scans a new channel and controls the detected base station to transmit a ranging request message including a CRID and a ranging target indication field set to a value indicating a network re-entry in accordance with the field departure. Thereafter, when the ranging response message is received from the base station, the optimized network re-entry procedure can be performed according to the value of the HO Process Optimization field included in the ranging response message.

In addition, the processor of the terminal may perform an overall control operation of the operation procedure described in the above embodiments.

The transmission modules 40 and 50 may perform predetermined coding and modulation on the data to be transmitted to the outside and transmit the data to the antenna 10 after being scheduled from the processors 20 and 30.

The receiving modules 60 and 70 decode and demodulate the radio signals received from the outside through the antennas 5 and 10 to restore them in the form of original data and transmit them to the processors 20 and 30 .

The memories 80 and 90 may store a program for processing and controlling the processors 20 and 30 and may perform functions for temporary storage of input / output data (restart count, etc.). The memories 80 and 90 may be a flash memory type, a hard disk type, a multimedia card micro type, a card type memory (for example, SD or XD memory A static random access memory (SRAM), a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), a programmable read-only memory (PROM) Magnetic disk, magnetic disk, magnetic disk, or optical disk.

The base station includes a controller function for performing the above-described embodiments of the present invention, orthogonal frequency division multiple access (OFDMA) packet scheduling, time division duplex (TDD) packet scheduling and channel multiplexing , MAC frame variable control function according to service characteristics and propagation environment, high speed traffic real time control function, handover function, authentication and encryption function, packet modulation / demodulation function for data transmission, high speed packet channel coding function and real time modem control function Etc. may be performed through at least one of the modules described above, or may include additional means, modules, or portions for performing such functions.

The present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Accordingly, the above description should not be construed in a limiting sense in all respects and should be considered illustrative. The scope of the present invention should be determined by rational interpretation of the appended claims, and all changes within the scope of equivalents of the present invention are included in the scope of the present invention. In addition, claims that do not have an explicit citation in the claims may be combined to form an embodiment or be included in a new claim by amendment after the filing.

Claims (15)

A method for detecting a coverage loss of a terminal operating in a sleep mode in a broadband wireless access system,
Awake before a sleep window is terminated to receive a superframe header (SFH) transmitted from a serving base station immediately before a frame in which a listening window is located;
Awake in both the sleep window and the listening window until successfully receiving a next superframe header from the serving BS if the superframe header is not successfully received; And
And receiving uplink resource allocation information (UL grant) from the serving base station,
When the active BS is in the sleep window when the active timer expires when the serving BS receives data from the MS, the uplink resource allocation information is transmitted to the BS in the nearest listening window at the expiration of the active timer A method for detecting an area defect, which is received. delete delete delete delete delete delete delete delete delete A terminal apparatus operating in a sleep mode in a broadband wireless access system,
A processor; And
And a wireless communication (RF) module for transmitting and receiving a wireless signal to and from the outside under the control of the processor,
The processor wakes up before a sleep window is terminated to receive a superframe header (SFH) transmitted from a serving base station immediately before a frame in which a listening window is located, and transmits the superframe header successfully The base station is awake in both the sleep window and the listening window until it successfully receives a superframe header to be transmitted next from the serving base station and receives uplink resource allocation information (UL grant) from the serving base station Respectively,
When the active BS is in the sleep window when the active timer expires when the serving BS receives data from the MS, the uplink resource allocation information is transmitted to the BS in the nearest listening window at the expiration of the active timer A terminal device as claimed in claim 1, delete delete delete delete

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